all: Add filesystem notification support

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3986

cmd/syncthing/main.go

@@ -1095,6 +1095,7 @@ func defaultConfig(myName string) config.Configuration {
 		defaultFolder = config.NewFolderConfiguration("default", fs.FilesystemTypeBasic, locations[locDefFolder])
 		defaultFolder.Label = "Default Folder"
 		defaultFolder.RescanIntervalS = 60
+		defaultFolder.FSWatcherDelayS = 10
 		defaultFolder.MinDiskFree = config.Size{Value: 1, Unit: "%"}
 		defaultFolder.Devices = []config.FolderDeviceConfiguration{{DeviceID: myID}}
 		defaultFolder.AutoNormalize = true

gui/default/index.html

@@ -368,7 +368,13 @@
                         <span translate>Yes</span>
                       </td>
                     </tr>
-                    <tr ng-if="folder.rescanIntervalS != 60">
+                    <tr ng-if="folder.fsNotifications">
+                      <th><span class="fa fa-fw fa-bolt"></span>&nbsp;<span translate>Filesystem Notifications</span></th>
+                      <td class="text-right">
+                        <span translate>Yes</span>
+                      </td>
+                    </tr>
+                    <tr ng-if="(folder.rescanIntervalS != 60 && !folder.fsNotifications) || (folder.rescanIntervalS != 3600 && folder.fsNotifications)">
                       <th><span class="fa fa-fw fa-refresh"></span>&nbsp;<span translate>Rescan Interval</span></th>
                       <td class="text-right">{{folder.rescanIntervalS}} s</td>
                     </tr>

gui/default/syncthing/core/syncthingController.js

@@ -50,7 +50,6 @@ angular.module('syncthing.core')
         $scope.neededPageSize = 10;
         $scope.failed = {};
         $scope.failedCurrentPage = 1;
-        $scope.failedCurrentFolder = undefined;
         $scope.failedPageSize = 10;
         $scope.scanProgress = {};
         $scope.themes = [];
@@ -66,6 +65,7 @@ angular.module('syncthing.core')
             selectedDevices: {},
             type: "readwrite",
             rescanIntervalS: 60,
+            fsWatcherDelayS: 10,
             minDiskFree: {value: 1, unit: "%"},
             maxConflicts: 10,
             fsync: true,

jenkins/build-macos.bash

@@ -25,6 +25,9 @@ platforms=(
 	darwin-amd64 darwin-386
 )
 
+# Mac builds always require cgo
+export CGO_ENABLED=1
+
 echo Building
 for plat in "${platforms[@]}"; do
 	echo Building "$plat"

lib/config/config.go

@@ -32,7 +32,7 @@ import (
 
 const (
 	OldestHandledVersion = 10
-	CurrentVersion       = 24
+	CurrentVersion       = 25
 	MaxRescanIntervalS   = 365 * 24 * 60 * 60
 )
 
@@ -326,6 +326,9 @@ func (cfg *Configuration) clean() error {
 	if cfg.Version == 23 {
 		convertV23V24(cfg)
 	}
+	if cfg.Version == 24 {
+		convertV24V25(cfg)
+	}
 
 	// Build a list of available devices
 	existingDevices := make(map[protocol.DeviceID]bool)
@@ -375,6 +378,14 @@ func (cfg *Configuration) clean() error {
 	return nil
 }
 
+func convertV24V25(cfg *Configuration) {
+	for i := range cfg.Folders {
+		cfg.Folders[i].FSWatcherDelayS = 10
+	}
+
+	cfg.Version = 25
+}
+
 func convertV23V24(cfg *Configuration) {
 	cfg.Options.URSeen = 2
 

lib/config/config_test.go

@@ -102,18 +102,20 @@ func TestDeviceConfig(t *testing.T) {
 
 		expectedFolders := []FolderConfiguration{
 			{
-				ID:              "test",
-				FilesystemType:  fs.FilesystemTypeBasic,
-				Path:            "testdata",
-				Devices:         []FolderDeviceConfiguration{{DeviceID: device1}, {DeviceID: device4}},
-				Type:            FolderTypeSendOnly,
-				RescanIntervalS: 600,
-				Copiers:         0,
-				Pullers:         0,
-				Hashers:         0,
-				AutoNormalize:   true,
-				MinDiskFree:     Size{1, "%"},
-				MaxConflicts:    -1,
+				ID:               "test",
+				FilesystemType:   fs.FilesystemTypeBasic,
+				Path:             "testdata",
+				Devices:          []FolderDeviceConfiguration{{DeviceID: device1}, {DeviceID: device4}},
+				Type:             FolderTypeSendOnly,
+				RescanIntervalS:  600,
+				FSWatcherEnabled: false,
+				FSWatcherDelayS:  10,
+				Copiers:          0,
+				Pullers:          0,
+				Hashers:          0,
+				AutoNormalize:    true,
+				MinDiskFree:      Size{1, "%"},
+				MaxConflicts:     -1,
 				Versioning: VersioningConfiguration{
 					Params: map[string]string{},
 				},

lib/config/folderconfiguration.go

@@ -22,6 +22,8 @@ type FolderConfiguration struct {
 	Type                  FolderType                  `xml:"type,attr" json:"type"`
 	Devices               []FolderDeviceConfiguration `xml:"device" json:"devices"`
 	RescanIntervalS       int                         `xml:"rescanIntervalS,attr" json:"rescanIntervalS"`
+	FSWatcherEnabled      bool                        `xml:"fsWatcherEnabled,attr" json:"fsWatcherEnabled"`
+	FSWatcherDelayS       int                         `xml:"fsWatcherDelayS,attr" json:"fsWatcherDelayS"`
 	IgnorePerms           bool                        `xml:"ignorePerms,attr" json:"ignorePerms"`
 	AutoNormalize         bool                        `xml:"autoNormalize,attr" json:"autoNormalize"`
 	MinDiskFree           Size                        `xml:"minDiskFree" json:"minDiskFree"`
@@ -157,6 +159,11 @@ func (f *FolderConfiguration) prepare() {
 		f.RescanIntervalS = 0
 	}
 
+	if f.FSWatcherDelayS <= 0 {
+		f.FSWatcherEnabled = false
+		f.FSWatcherDelayS = 10
+	}
+
 	if f.Versioning.Params == nil {
 		f.Versioning.Params = make(map[string]string)
 	}

lib/config/testdata/v25.xml

@@ -0,0 +1,16 @@
+<configuration version="25">
+    <folder id="test" path="testdata" type="readonly" ignorePerms="false" rescanIntervalS="600" fsNotifications="false" notifyDelayS="10" autoNormalize="true">
+        <filesystemType>basic</filesystemType>
+        <device id="AIR6LPZ-7K4PTTV-UXQSMUU-CPQ5YWH-OEDFIIQ-JUG777G-2YQXXR5-YD6AWQR"></device>
+        <device id="P56IOI7-MZJNU2Y-IQGDREY-DM2MGTI-MGL3BXN-PQ6W5BM-TBBZ4TJ-XZWICQ2"></device>
+        <minDiskFree unit="%">1</minDiskFree>
+        <maxConflicts>-1</maxConflicts>
+        <fsync>true</fsync>
+    </folder>
+    <device id="AIR6LPZ-7K4PTTV-UXQSMUU-CPQ5YWH-OEDFIIQ-JUG777G-2YQXXR5-YD6AWQR" name="node one" compression="metadata">
+        <address>tcp://a</address>
+    </device>
+    <device id="P56IOI7-MZJNU2Y-IQGDREY-DM2MGTI-MGL3BXN-PQ6W5BM-TBBZ4TJ-XZWICQ2" name="node two" compression="metadata">
+        <address>tcp://b</address>
+    </device>
+</configuration>

lib/fs/basicfs_test.go

@@ -7,12 +7,14 @@
 package fs
 
 import (
+	"errors"
 	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
 	"sort"
 	"strings"
+	"syscall"
 	"testing"
 	"time"
 )
@@ -484,3 +486,23 @@ func TestRooted(t *testing.T) {
 		}
 	}
 }
+
+func TestWatchErrorLinuxInterpretation(t *testing.T) {
+	if runtime.GOOS != "linux" {
+		t.Skip("testing of linux specific error codes")
+	}
+
+	var errTooManyFiles syscall.Errno = 24
+	var errNoSpace syscall.Errno = 28
+
+	if !reachedMaxUserWatches(errTooManyFiles) {
+		t.Errorf("Errno %v should be recognised to be about inotify limits.", errTooManyFiles)
+	}
+	if !reachedMaxUserWatches(errNoSpace) {
+		t.Errorf("Errno %v should be recognised to be about inotify limits.", errNoSpace)
+	}
+	err := errors.New("Another error")
+	if reachedMaxUserWatches(err) {
+		t.Errorf("This error does not concern inotify limits: %#v", err)
+	}
+}

lib/fs/basicfs_watch.go

@@ -0,0 +1,116 @@
+// Copyright (C) 2016 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// +build !solaris,!darwin solaris,cgo darwin,cgo
+
+package fs
+
+import (
+	"context"
+	"errors"
+	"path/filepath"
+
+	"github.com/zillode/notify"
+)
+
+// Notify does not block on sending to channel, so the channel must be buffered.
+// The actual number is magic.
+// Not meant to be changed, but must be changeable for tests
+var backendBuffer = 500
+
+func (f *BasicFilesystem) Watch(name string, ignore Matcher, ctx context.Context, ignorePerms bool) (<-chan Event, error) {
+	absName, err := f.rooted(name)
+	if err != nil {
+		return nil, err
+	}
+
+	absShouldIgnore := func(absPath string) bool {
+		return ignore.ShouldIgnore(f.unrootedChecked(absPath))
+	}
+
+	outChan := make(chan Event)
+	backendChan := make(chan notify.EventInfo, backendBuffer)
+
+	eventMask := subEventMask
+	if !ignorePerms {
+		eventMask |= permEventMask
+	}
+
+	if err := notify.WatchWithFilter(filepath.Join(absName, "..."), backendChan, absShouldIgnore, eventMask); err != nil {
+		notify.Stop(backendChan)
+		if reachedMaxUserWatches(err) {
+			err = errors.New("failed to install inotify handler. Please increase inotify limits, see https://github.com/syncthing/syncthing-inotify#troubleshooting-for-folders-with-many-files-on-linux for more information")
+		}
+		return nil, err
+	}
+
+	go f.watchLoop(name, absName, backendChan, outChan, ignore, ctx)
+
+	return outChan, nil
+}
+
+func (f *BasicFilesystem) watchLoop(name string, absName string, backendChan chan notify.EventInfo, outChan chan<- Event, ignore Matcher, ctx context.Context) {
+	for {
+		// Detect channel overflow
+		if len(backendChan) == backendBuffer {
+		outer:
+			for {
+				select {
+				case <-backendChan:
+				default:
+					break outer
+				}
+			}
+			// When next scheduling a scan, do it on the entire folder as events have been lost.
+			outChan <- Event{Name: name, Type: NonRemove}
+			l.Debugln(f.Type(), f.URI(), "Watch: Event overflow, send \".\"")
+		}
+
+		select {
+		case ev := <-backendChan:
+			relPath := f.unrootedChecked(ev.Path())
+			if ignore.ShouldIgnore(relPath) {
+				l.Debugln(f.Type(), f.URI(), "Watch: Ignoring", relPath)
+				continue
+			}
+			evType := f.eventType(ev.Event())
+			select {
+			case outChan <- Event{Name: relPath, Type: evType}:
+				l.Debugln(f.Type(), f.URI(), "Watch: Sending", relPath, evType)
+			case <-ctx.Done():
+				notify.Stop(backendChan)
+				l.Debugln(f.Type(), f.URI(), "Watch: Stopped")
+				return
+			}
+		case <-ctx.Done():
+			notify.Stop(backendChan)
+			l.Debugln(f.Type(), f.URI(), "Watch: Stopped")
+			return
+		}
+	}
+}
+
+func (f *BasicFilesystem) eventType(notifyType notify.Event) EventType {
+	if notifyType&rmEventMask != 0 {
+		return Remove
+	}
+	return NonRemove
+}
+
+// unrootedChecked returns the path relative to the folder root (same as
+// unrooted). It panics if the given path is not a subpath and handles the
+// special case when the given path is the folder root without a trailing
+// pathseparator.
+func (f *BasicFilesystem) unrootedChecked(absPath string) string {
+	if absPath+string(PathSeparator) == f.root {
+		return "."
+	}
+	relPath := f.unrooted(absPath)
+	if relPath == absPath {
+		panic("bug: Notify backend is processing a change outside of the watched path: " + absPath)
+	}
+	return relPath
+}

lib/fs/basicfs_watch_errors_linux.go

@@ -0,0 +1,18 @@
+// Copyright (C) 2016 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// +build linux
+
+package fs
+
+import "syscall"
+
+func reachedMaxUserWatches(err error) bool {
+	if errno, ok := err.(syscall.Errno); ok {
+		return errno == 24 || errno == 28
+	}
+	return false
+}

lib/fs/basicfs_watch_errors_others.go

@@ -0,0 +1,13 @@
+// Copyright (C) 2016 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// +build !linux
+
+package fs
+
+func reachedMaxUserWatches(err error) bool {
+	return false
+}

lib/fs/basicfs_watch_eventtypes_fen.go

@@ -0,0 +1,17 @@
+// Copyright (C) 2017 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// +build solaris,cgo
+
+package fs
+
+import "github.com/zillode/notify"
+
+const (
+	subEventMask  = notify.Create | notify.FileModified | notify.FileRenameFrom | notify.FileDelete | notify.FileRenameTo
+	permEventMask = notify.FileAttrib
+	rmEventMask   = notify.FileDelete | notify.FileRenameFrom
+)

lib/fs/basicfs_watch_eventtypes_inotify.go

@@ -0,0 +1,17 @@
+// Copyright (C) 2017 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// +build linux
+
+package fs
+
+import "github.com/zillode/notify"
+
+const (
+	subEventMask  = notify.InCreate | notify.InMovedTo | notify.InDelete | notify.InDeleteSelf | notify.InModify | notify.InMovedFrom | notify.InMoveSelf
+	permEventMask = notify.InAttrib
+	rmEventMask   = notify.InDelete | notify.InDeleteSelf | notify.InMovedFrom | notify.InMoveSelf
+)

lib/fs/basicfs_watch_eventtypes_kqueue.go

@@ -0,0 +1,17 @@
+// Copyright (C) 2017 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// +build dragonfly freebsd netbsd openbsd
+
+package fs
+
+import "github.com/zillode/notify"
+
+const (
+	subEventMask  = notify.NoteDelete | notify.NoteWrite | notify.NoteRename
+	permEventMask = notify.NoteAttrib
+	rmEventMask   = notify.NoteDelete | notify.NoteRename
+)

lib/fs/basicfs_watch_eventtypes_other.go

@@ -0,0 +1,21 @@
+// Copyright (C) 2017 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// +build !linux,!windows,!dragonfly,!freebsd,!netbsd,!openbsd,!solaris
+// +build !darwin darwin,cgo
+
+// Catch all platforms that are not specifically handled to use the generic
+// event types.
+
+package fs
+
+import "github.com/zillode/notify"
+
+const (
+	subEventMask  = notify.All
+	permEventMask = 0
+	rmEventMask   = notify.Remove | notify.Rename
+)

lib/fs/basicfs_watch_eventtypes_readdcw.go

@@ -0,0 +1,17 @@
+// Copyright (C) 2017 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// +build windows
+
+package fs
+
+import "github.com/zillode/notify"
+
+const (
+	subEventMask  = notify.FileNotifyChangeFileName | notify.FileNotifyChangeDirName | notify.FileNotifyChangeSize | notify.FileNotifyChangeCreation
+	permEventMask = notify.FileNotifyChangeAttributes
+	rmEventMask   = notify.FileActionRemoved | notify.FileActionRenamedOldName
+)

lib/fs/basicfs_watch_test.go

@@ -0,0 +1,295 @@
+// Copyright (C) 2016 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// +build !solaris,!darwin solaris,cgo darwin,cgo
+
+package fs
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strconv"
+	"testing"
+	"time"
+
+	"github.com/zillode/notify"
+)
+
+func TestMain(m *testing.M) {
+	if err := os.RemoveAll(testDir); err != nil {
+		panic(err)
+	}
+
+	dir, err := filepath.Abs(".")
+	if err != nil {
+		panic("Cannot get absolute path to working dir")
+	}
+	dir, err = filepath.EvalSymlinks(dir)
+	if err != nil {
+		panic("Cannot get real path to working dir")
+	}
+	testDirAbs = filepath.Join(dir, testDir)
+	testFs = newBasicFilesystem(testDirAbs)
+	if l.ShouldDebug("filesystem") {
+		testFs = &logFilesystem{testFs}
+	}
+
+	backendBuffer = 10
+	defer func() {
+		backendBuffer = 500
+	}()
+	os.Exit(m.Run())
+}
+
+const (
+	testDir = "temporary_test_root"
+)
+
+var (
+	testDirAbs string
+	testFs     Filesystem
+)
+
+func TestWatchIgnore(t *testing.T) {
+	name := "ignore"
+
+	file := "file"
+	ignored := "ignored"
+
+	testCase := func() {
+		createTestFile(name, file)
+		createTestFile(name, ignored)
+	}
+
+	expectedEvents := []Event{
+		{file, NonRemove},
+	}
+
+	testScenario(t, name, testCase, expectedEvents, false, ignored)
+}
+
+func TestWatchRename(t *testing.T) {
+	name := "rename"
+
+	old := createTestFile(name, "oldfile")
+	new := "newfile"
+
+	testCase := func() {
+		renameTestFile(name, old, new)
+	}
+
+	destEvent := Event{new, Remove}
+	// Only on these platforms the removed file can be differentiated from
+	// the created file during renaming
+	if runtime.GOOS == "windows" || runtime.GOOS == "linux" || runtime.GOOS == "solaris" {
+		destEvent = Event{new, NonRemove}
+	}
+	expectedEvents := []Event{
+		{old, Remove},
+		destEvent,
+	}
+
+	testScenario(t, name, testCase, expectedEvents, false, "")
+}
+
+// TestWatchOutside checks that no changes from outside the folder make it in
+func TestWatchOutside(t *testing.T) {
+	outChan := make(chan Event)
+	backendChan := make(chan notify.EventInfo, backendBuffer)
+
+	ctx, cancel := context.WithCancel(context.Background())
+
+	// testFs is Filesystem, but we need BasicFilesystem here
+	fs := newBasicFilesystem(testDirAbs)
+
+	go func() {
+		defer func() {
+			if recover() == nil {
+				t.Fatalf("Watch did not panic on receiving event outside of folder")
+			}
+			cancel()
+		}()
+		fs.watchLoop(".", testDirAbs, backendChan, outChan, fakeMatcher{}, ctx)
+	}()
+
+	backendChan <- fakeEventInfo(filepath.Join(filepath.Dir(testDirAbs), "outside"))
+}
+
+func TestWatchSubpath(t *testing.T) {
+	outChan := make(chan Event)
+	backendChan := make(chan notify.EventInfo, backendBuffer)
+
+	ctx, cancel := context.WithCancel(context.Background())
+
+	// testFs is Filesystem, but we need BasicFilesystem here
+	fs := newBasicFilesystem(testDirAbs)
+
+	abs, _ := fs.rooted("sub")
+	go fs.watchLoop("sub", abs, backendChan, outChan, fakeMatcher{}, ctx)
+
+	backendChan <- fakeEventInfo(filepath.Join(abs, "file"))
+
+	timeout := time.NewTimer(2 * time.Second)
+	select {
+	case <-timeout.C:
+		t.Errorf("Timed out before receiving an event")
+		cancel()
+	case ev := <-outChan:
+		if ev.Name != filepath.Join("sub", "file") {
+			t.Errorf("While watching a subfolder, received an event with unexpected path %v", ev.Name)
+		}
+	}
+
+	cancel()
+}
+
+// TestWatchOverflow checks that an event at the root is sent when maxFiles is reached
+func TestWatchOverflow(t *testing.T) {
+	name := "overflow"
+
+	testCase := func() {
+		for i := 0; i < 5*backendBuffer; i++ {
+			createTestFile(name, "file"+strconv.Itoa(i))
+		}
+	}
+
+	expectedEvents := []Event{
+		{".", NonRemove},
+	}
+
+	testScenario(t, name, testCase, expectedEvents, true, "")
+}
+
+// path relative to folder root, also creates parent dirs if necessary
+func createTestFile(name string, file string) string {
+	joined := filepath.Join(name, file)
+	if err := testFs.MkdirAll(filepath.Dir(joined), 0755); err != nil {
+		panic(fmt.Sprintf("Failed to create parent directory for %s: %s", joined, err))
+	}
+	handle, err := testFs.Create(joined)
+	if err != nil {
+		panic(fmt.Sprintf("Failed to create test file %s: %s", joined, err))
+	}
+	handle.Close()
+	return file
+}
+
+func renameTestFile(name string, old string, new string) {
+	old = filepath.Join(name, old)
+	new = filepath.Join(name, new)
+	if err := testFs.Rename(old, new); err != nil {
+		panic(fmt.Sprintf("Failed to rename %s to %s: %s", old, new, err))
+	}
+}
+
+func sleepMs(ms int) {
+	time.Sleep(time.Duration(ms) * time.Millisecond)
+}
+
+func testScenario(t *testing.T, name string, testCase func(), expectedEvents []Event, allowOthers bool, ignored string) {
+	if err := testFs.MkdirAll(name, 0755); err != nil {
+		panic(fmt.Sprintf("Failed to create directory %s: %s", name, err))
+	}
+
+	// Tests pick up the previously created files/dirs, probably because
+	// they get flushed to disk with a delay.
+	initDelayMs := 500
+	if runtime.GOOS == "darwin" {
+		initDelayMs = 900
+	}
+	sleepMs(initDelayMs)
+
+	ctx, cancel := context.WithCancel(context.Background())
+
+	if ignored != "" {
+		ignored = filepath.Join(name, ignored)
+	}
+
+	eventChan, err := testFs.Watch(name, fakeMatcher{ignored}, ctx, false)
+	if err != nil {
+		panic(err)
+	}
+
+	go testWatchOutput(t, name, eventChan, expectedEvents, allowOthers, ctx, cancel)
+
+	timeout := time.NewTimer(2 * time.Second)
+
+	testCase()
+
+	select {
+	case <-timeout.C:
+		t.Errorf("Timed out before receiving all expected events")
+		cancel()
+	case <-ctx.Done():
+	}
+
+	if err := testFs.RemoveAll(name); err != nil {
+		panic(fmt.Sprintf("Failed to remove directory %s: %s", name, err))
+	}
+}
+
+func testWatchOutput(t *testing.T, name string, in <-chan Event, expectedEvents []Event, allowOthers bool, ctx context.Context, cancel context.CancelFunc) {
+	var expected = make(map[Event]struct{})
+	for _, ev := range expectedEvents {
+		ev.Name = filepath.Join(name, ev.Name)
+		expected[ev] = struct{}{}
+	}
+
+	var received Event
+	var last Event
+	for {
+		if len(expected) == 0 {
+			cancel()
+			return
+		}
+
+		select {
+		case <-ctx.Done():
+			return
+		case received = <-in:
+		}
+
+		// apparently the backend sometimes sends repeat events
+		if last == received {
+			continue
+		}
+
+		if _, ok := expected[received]; !ok {
+			if allowOthers {
+				sleepMs(100) // To facilitate overflow
+				continue
+			}
+			t.Errorf("Received unexpected event %v expected one of %v", received, expected)
+			cancel()
+			return
+		}
+		delete(expected, received)
+		last = received
+	}
+}
+
+type fakeMatcher struct{ match string }
+
+func (fm fakeMatcher) ShouldIgnore(name string) bool {
+	return name == fm.match
+}
+
+type fakeEventInfo string
+
+func (e fakeEventInfo) Path() string {
+	return string(e)
+}
+
+func (e fakeEventInfo) Event() notify.Event {
+	return notify.Write
+}
+
+func (e fakeEventInfo) Sys() interface{} {
+	return nil
+}

lib/fs/basicfs_watch_unsupported.go

@@ -0,0 +1,15 @@
+// Copyright (C) 2016 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// +build solaris,!cgo darwin,!cgo
+
+package fs
+
+import "context"
+
+func (f *BasicFilesystem) Watch(path string, ignore Matcher, ctx context.Context, ignorePerms bool) (<-chan Event, error) {
+	return nil, ErrWatchNotSupported
+}

lib/fs/errorfs.go

@@ -6,7 +6,10 @@
 
 package fs
 
-import "time"
+import (
+	"context"
+	"time"
+)
 
 type errorFilesystem struct {
 	err    error
@@ -39,3 +42,6 @@ func (fs *errorFilesystem) Roots() ([]string, error)
 func (fs *errorFilesystem) Usage(name string) (Usage, error)                            { return Usage{}, fs.err }
 func (fs *errorFilesystem) Type() FilesystemType                                        { return fs.fsType }
 func (fs *errorFilesystem) URI() string                                                 { return fs.uri }
+func (fs *errorFilesystem) Watch(path string, ignore Matcher, ctx context.Context, ignorePerms bool) (<-chan Event, error) {
+	return nil, fs.err
+}

lib/fs/filesystem.go

@@ -7,6 +7,7 @@
 package fs
 
 import (
+	"context"
 	"errors"
 	"io"
 	"os"
@@ -33,7 +34,8 @@ type Filesystem interface {
 	Rename(oldname, newname string) error
 	Stat(name string) (FileInfo, error)
 	SymlinksSupported() bool
-	Walk(root string, walkFn WalkFunc) error
+	Walk(name string, walkFn WalkFunc) error
+	Watch(path string, ignore Matcher, ctx context.Context, ignorePerms bool) (<-chan Event, error)
 	Hide(name string) error
 	Unhide(name string) error
 	Glob(pattern string) ([]string, error)
@@ -82,6 +84,42 @@ type Usage struct {
 	Total int64
 }
 
+type Matcher interface {
+	ShouldIgnore(name string) bool
+}
+
+type MatchResult interface {
+	IsIgnored() bool
+}
+
+type Event struct {
+	Name string
+	Type EventType
+}
+
+type EventType int
+
+const (
+	NonRemove EventType = 1 + iota
+	Remove
+	Mixed // Should probably not be necessary to be used in filesystem interface implementation
+)
+
+func (evType EventType) String() string {
+	switch {
+	case evType == NonRemove:
+		return "non-remove"
+	case evType == Remove:
+		return "remove"
+	case evType == Mixed:
+		return "mixed"
+	default:
+		panic("bug: Unknown event type")
+	}
+}
+
+var ErrWatchNotSupported = errors.New("watching is not supported")
+
 // Equivalents from os package.
 
 const ModePerm = FileMode(os.ModePerm)

lib/fs/logfs.go

@@ -7,6 +7,7 @@
 package fs
 
 import (
+	"context"
 	"fmt"
 	"path/filepath"
 	"runtime"
@@ -127,6 +128,12 @@ func (fs *logFilesystem) Walk(root string, walkFn WalkFunc) error {
 	return err
 }
 
+func (fs *logFilesystem) Watch(path string, ignore Matcher, ctx context.Context, ignorePerms bool) (<-chan Event, error) {
+	evChan, err := fs.Filesystem.Watch(path, ignore, ctx, ignorePerms)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "Watch", path, ignore, ignorePerms, err)
+	return evChan, err
+}
+
 func (fs *logFilesystem) Unhide(name string) error {
 	err := fs.Filesystem.Unhide(name)
 	l.Debugln(getCaller(), fs.Type(), fs.URI(), "Unhide", name, err)

lib/model/folder.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/syncthing/syncthing/lib/config"
+	"github.com/syncthing/syncthing/lib/watchaggregator"
 )
 
 type folder struct {
@@ -22,6 +23,9 @@ type folder struct {
 	ctx                 context.Context
 	cancel              context.CancelFunc
 	initialScanFinished chan struct{}
+	watchCancel         context.CancelFunc
+	watchChan           chan []string
+	ignoresUpdated      chan struct{} // The ignores changed, we need to restart watcher
 }
 
 func newFolder(model *Model, cfg config.FolderConfiguration) folder {
@@ -92,3 +96,35 @@ func (f *folder) scanTimerFired() {
 
 	f.scan.Reschedule()
 }
+
+func (f *folder) startWatcher() {
+	ctx, cancel := context.WithCancel(f.ctx)
+	f.model.fmut.RLock()
+	ignores := f.model.folderIgnores[f.folderID]
+	f.model.fmut.RUnlock()
+	eventChan, err := f.Filesystem().Watch(".", ignores, ctx, f.IgnorePerms)
+	if err != nil {
+		l.Warnf("Failed to start filesystem watcher for folder %s: %v", f.Description(), err)
+	} else {
+		f.watchChan = make(chan []string)
+		f.watchCancel = cancel
+		watchaggregator.Aggregate(eventChan, f.watchChan, f.FolderConfiguration, f.model.cfg, ctx)
+		l.Infoln("Started filesystem watcher for folder", f.Description())
+	}
+}
+
+func (f *folder) restartWatcher() {
+	f.watchCancel()
+	f.startWatcher()
+	f.Scan(nil)
+}
+
+func (f *folder) IgnoresUpdated() {
+	select {
+	case f.ignoresUpdated <- struct{}{}:
+	default:
+		// We might be busy doing a pull and thus not reading from this
+		// channel. The channel is 1-buffered, so one notification will be
+		// queued to ensure we recheck after the pull.
+	}
+}

lib/model/model.go

@@ -48,6 +48,7 @@ type service interface {
 	BringToFront(string)
 	DelayScan(d time.Duration)
 	IndexUpdated()              // Remote index was updated notification
+	IgnoresUpdated()            // ignore matcher was updated notification
 	Jobs() ([]string, []string) // In progress, Queued
 	Scan(subs []string) error
 	Serve()
@@ -260,6 +261,7 @@ func (m *Model) startFolderLocked(folder string) config.FolderType {
 	ffs.Hide(".stignore")
 
 	p := folderFactory(m, cfg, ver, ffs)
+
 	m.folderRunners[folder] = p
 
 	m.warnAboutOverwritingProtectedFiles(folder)
@@ -1858,7 +1860,7 @@ func (m *Model) internalScanFolderSubdirs(ctx context.Context, folder string, su
 	defer func() {
 		if ignores.Hash() != oldHash {
 			l.Debugln("Folder", folder, "ignore patterns changed; triggering puller")
-			runner.IndexUpdated()
+			runner.IgnoresUpdated()
 		}
 	}()
 

lib/model/rofolder.go

@@ -34,11 +34,20 @@ func (f *sendOnlyFolder) Serve() {
 		f.scan.timer.Stop()
 	}()
 
+	if f.FSWatcherEnabled {
+		f.startWatcher()
+	}
+
 	for {
 		select {
 		case <-f.ctx.Done():
 			return
 
+		case <-f.ignoresUpdated:
+			if f.FSWatcherEnabled {
+				f.restartWatcher()
+			}
+
 		case <-f.scan.timer.C:
 			l.Debugln(f, "Scanning subdirectories")
 			f.scanTimerFired()
@@ -48,6 +57,10 @@ func (f *sendOnlyFolder) Serve() {
 
 		case next := <-f.scan.delay:
 			f.scan.timer.Reset(next)
+
+		case fsEvents := <-f.watchChan:
+			l.Debugln(f, "filesystem notification rescan")
+			f.scanSubdirs(fsEvents)
 		}
 	}
 }

lib/model/rwfolder.go

@@ -164,6 +164,10 @@ func (f *sendReceiveFolder) Serve() {
 	var prevSec int64
 	var prevIgnoreHash string
 
+	if f.FSWatcherEnabled {
+		f.startWatcher()
+	}
+
 	for {
 		select {
 		case <-f.ctx.Done():
@@ -174,6 +178,12 @@ func (f *sendReceiveFolder) Serve() {
 			f.pullTimer.Reset(0)
 			l.Debugln(f, "remote index updated, rescheduling pull")
 
+		case <-f.ignoresUpdated:
+			if f.FSWatcherEnabled {
+				f.restartWatcher()
+			}
+			f.IndexUpdated()
+
 		case <-f.pullTimer.C:
 			select {
 			case <-f.initialScanFinished:
@@ -278,6 +288,10 @@ func (f *sendReceiveFolder) Serve() {
 
 		case next := <-f.scan.delay:
 			f.scan.timer.Reset(next)
+
+		case fsEvents := <-f.watchChan:
+			l.Debugln(f, "filesystem notification rescan")
+			f.scanSubdirs(fsEvents)
 		}
 	}
 }

lib/watchaggregator/aggregator.go

@@ -0,0 +1,438 @@
+// Copyright (C) 2016 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package watchaggregator
+
+import (
+	"context"
+	"fmt"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/syncthing/syncthing/lib/config"
+	"github.com/syncthing/syncthing/lib/events"
+	"github.com/syncthing/syncthing/lib/fs"
+)
+
+// Not meant to be changed, but must be changeable for tests
+var (
+	maxFiles       = 512
+	maxFilesPerDir = 128
+)
+
+// aggregatedEvent represents potentially multiple events at and/or recursively
+// below one path until it times out and a scan is scheduled.
+type aggregatedEvent struct {
+	firstModTime time.Time
+	lastModTime  time.Time
+	evType       fs.EventType
+}
+
+// Stores pointers to both aggregated events directly within this directory and
+// child directories recursively containing aggregated events themselves.
+type eventDir struct {
+	events map[string]*aggregatedEvent
+	dirs   map[string]*eventDir
+}
+
+func newEventDir() *eventDir {
+	return &eventDir{
+		events: make(map[string]*aggregatedEvent),
+		dirs:   make(map[string]*eventDir),
+	}
+}
+
+func (dir *eventDir) eventCount() int {
+	count := len(dir.events)
+	for _, dir := range dir.dirs {
+		count += dir.eventCount()
+	}
+	return count
+}
+
+func (dir *eventDir) childCount() int {
+	return len(dir.events) + len(dir.dirs)
+}
+
+func (dir *eventDir) firstModTime() time.Time {
+	if dir.childCount() == 0 {
+		panic("bug: firstModTime must not be used on empty eventDir")
+	}
+	firstModTime := time.Now()
+	for _, childDir := range dir.dirs {
+		dirTime := childDir.firstModTime()
+		if dirTime.Before(firstModTime) {
+			firstModTime = dirTime
+		}
+	}
+	for _, event := range dir.events {
+		if event.firstModTime.Before(firstModTime) {
+			firstModTime = event.firstModTime
+		}
+	}
+	return firstModTime
+}
+
+func (dir *eventDir) eventType() fs.EventType {
+	if dir.childCount() == 0 {
+		panic("bug: eventType must not be used on empty eventDir")
+	}
+	var evType fs.EventType
+	for _, childDir := range dir.dirs {
+		evType |= childDir.eventType()
+		if evType == fs.Mixed {
+			return fs.Mixed
+		}
+	}
+	for _, event := range dir.events {
+		evType |= event.evType
+		if evType == fs.Mixed {
+			return fs.Mixed
+		}
+	}
+	return evType
+}
+
+type aggregator struct {
+	folderCfg       config.FolderConfiguration
+	folderCfgUpdate chan config.FolderConfiguration
+	// Time after which an event is scheduled for scanning when no modifications occur.
+	notifyDelay time.Duration
+	// Time after which an event is scheduled for scanning even though modifications occur.
+	notifyTimeout         time.Duration
+	notifyTimer           *time.Timer
+	notifyTimerNeedsReset bool
+	notifyTimerResetChan  chan time.Duration
+	ctx                   context.Context
+}
+
+func new(folderCfg config.FolderConfiguration, ctx context.Context) *aggregator {
+	a := &aggregator{
+		folderCfgUpdate:       make(chan config.FolderConfiguration),
+		notifyTimerNeedsReset: false,
+		notifyTimerResetChan:  make(chan time.Duration),
+		ctx:                   ctx,
+	}
+
+	a.updateConfig(folderCfg)
+
+	return a
+}
+
+func Aggregate(in <-chan fs.Event, out chan<- []string, folderCfg config.FolderConfiguration, cfg *config.Wrapper, ctx context.Context) {
+	a := new(folderCfg, ctx)
+
+	// Necessary for unit tests where the backend is mocked
+	go a.mainLoop(in, out, cfg)
+}
+
+func (a *aggregator) mainLoop(in <-chan fs.Event, out chan<- []string, cfg *config.Wrapper) {
+	a.notifyTimer = time.NewTimer(a.notifyDelay)
+	defer a.notifyTimer.Stop()
+
+	inProgress := make(map[string]struct{})
+	inProgressItemSubscription := events.Default.Subscribe(events.ItemStarted | events.ItemFinished)
+
+	cfg.Subscribe(a)
+
+	rootEventDir := newEventDir()
+
+	for {
+		select {
+		case event := <-in:
+			a.newEvent(event, rootEventDir, inProgress)
+		case event := <-inProgressItemSubscription.C():
+			updateInProgressSet(event, inProgress)
+		case <-a.notifyTimer.C:
+			a.actOnTimer(rootEventDir, out)
+		case interval := <-a.notifyTimerResetChan:
+			a.resetNotifyTimer(interval)
+		case folderCfg := <-a.folderCfgUpdate:
+			a.updateConfig(folderCfg)
+		case <-a.ctx.Done():
+			cfg.Unsubscribe(a)
+			l.Debugln(a, "Stopped")
+			return
+		}
+	}
+}
+
+func (a *aggregator) newEvent(event fs.Event, rootEventDir *eventDir, inProgress map[string]struct{}) {
+	if _, ok := rootEventDir.events["."]; ok {
+		l.Debugln(a, "Will scan entire folder anyway; dropping:", event.Name)
+		return
+	}
+	if _, ok := inProgress[event.Name]; ok {
+		l.Debugln(a, "Skipping path we modified:", event.Name)
+		return
+	}
+	a.aggregateEvent(event, time.Now(), rootEventDir)
+}
+
+func (a *aggregator) aggregateEvent(event fs.Event, evTime time.Time, rootEventDir *eventDir) {
+	if event.Name == "." || rootEventDir.eventCount() == maxFiles {
+		l.Debugln(a, "Scan entire folder")
+		firstModTime := evTime
+		if rootEventDir.childCount() != 0 {
+			event.Type |= rootEventDir.eventType()
+			firstModTime = rootEventDir.firstModTime()
+		}
+		rootEventDir.dirs = make(map[string]*eventDir)
+		rootEventDir.events = make(map[string]*aggregatedEvent)
+		rootEventDir.events["."] = &aggregatedEvent{
+			firstModTime: firstModTime,
+			lastModTime:  evTime,
+			evType:       event.Type,
+		}
+		a.resetNotifyTimerIfNeeded()
+		return
+	}
+
+	parentDir := rootEventDir
+
+	// Check if any parent directory is already tracked or will exceed
+	// events per directory limit bottom up
+	pathSegments := strings.Split(filepath.ToSlash(event.Name), "/")
+
+	// As root dir cannot be further aggregated, allow up to maxFiles
+	// children.
+	localMaxFilesPerDir := maxFiles
+	var currPath string
+	for i, name := range pathSegments[:len(pathSegments)-1] {
+		currPath = filepath.Join(currPath, name)
+
+		if ev, ok := parentDir.events[name]; ok {
+			ev.lastModTime = evTime
+			ev.evType |= event.Type
+			l.Debugf("%v Parent %s (type %s) already tracked: %s", a, currPath, ev.evType, event.Name)
+			return
+		}
+
+		if parentDir.childCount() == localMaxFilesPerDir {
+			l.Debugf("%v Parent dir %s already has %d children, tracking it instead: %s", a, currPath, localMaxFilesPerDir, event.Name)
+			event.Name = filepath.Dir(currPath)
+			a.aggregateEvent(event, evTime, rootEventDir)
+			return
+		}
+
+		// If there are no events below path, but we need to recurse
+		// into that path, create eventDir at path.
+		if newParent, ok := parentDir.dirs[name]; ok {
+			parentDir = newParent
+		} else {
+			l.Debugln(a, "Creating eventDir at:", currPath)
+			newParent = newEventDir()
+			parentDir.dirs[name] = newParent
+			parentDir = newParent
+		}
+
+		// Reset allowed children count to maxFilesPerDir for non-root
+		if i == 0 {
+			localMaxFilesPerDir = maxFilesPerDir
+		}
+	}
+
+	name := pathSegments[len(pathSegments)-1]
+
+	if ev, ok := parentDir.events[name]; ok {
+		ev.lastModTime = evTime
+		ev.evType |= event.Type
+		l.Debugf("%v Already tracked (type %v): %s", a, ev.evType, event.Name)
+		return
+	}
+
+	childDir, ok := parentDir.dirs[name]
+
+	// If a dir existed at path, it would be removed from dirs, thus
+	// childCount would not increase.
+	if !ok && parentDir.childCount() == localMaxFilesPerDir {
+		l.Debugf("%v Parent dir already has %d children, tracking it instead: %s", a, localMaxFilesPerDir, event.Name)
+		event.Name = filepath.Dir(event.Name)
+		a.aggregateEvent(event, evTime, rootEventDir)
+		return
+	}
+
+	firstModTime := evTime
+	if ok {
+		firstModTime = childDir.firstModTime()
+		event.Type |= childDir.eventType()
+		delete(parentDir.dirs, name)
+	}
+	l.Debugf("%v Tracking (type %v): %s", a, event.Type, event.Name)
+	parentDir.events[name] = &aggregatedEvent{
+		firstModTime: firstModTime,
+		lastModTime:  evTime,
+		evType:       event.Type,
+	}
+	a.resetNotifyTimerIfNeeded()
+}
+
+func (a *aggregator) resetNotifyTimerIfNeeded() {
+	if a.notifyTimerNeedsReset {
+		a.resetNotifyTimer(a.notifyDelay)
+	}
+}
+
+// resetNotifyTimer should only ever be called when notifyTimer has stopped
+// and notifyTimer.C been read from. Otherwise, call resetNotifyTimerIfNeeded.
+func (a *aggregator) resetNotifyTimer(duration time.Duration) {
+	l.Debugln(a, "Resetting notifyTimer to", duration.String())
+	a.notifyTimerNeedsReset = false
+	a.notifyTimer.Reset(duration)
+}
+
+func (a *aggregator) actOnTimer(rootEventDir *eventDir, out chan<- []string) {
+	eventCount := rootEventDir.eventCount()
+	if eventCount == 0 {
+		l.Debugln(a, "No tracked events, waiting for new event.")
+		a.notifyTimerNeedsReset = true
+		return
+	}
+	oldevents := a.popOldEvents(rootEventDir, ".", time.Now())
+	if len(oldevents) == 0 {
+		l.Debugln(a, "No old fs events")
+		a.resetNotifyTimer(a.notifyDelay)
+		return
+	}
+	// Sending to channel might block for a long time, but we need to keep
+	// reading from notify backend channel to avoid overflow
+	go a.notify(oldevents, out)
+}
+
+// Schedule scan for given events dispatching deletes last and reset notification
+// afterwards to set up for the next scan scheduling.
+func (a *aggregator) notify(oldEvents map[string]*aggregatedEvent, out chan<- []string) {
+	timeBeforeSending := time.Now()
+	l.Debugf("%v Notifying about %d fs events", a, len(oldEvents))
+	separatedBatches := make(map[fs.EventType][]string)
+	for path, event := range oldEvents {
+		separatedBatches[event.evType] = append(separatedBatches[event.evType], path)
+	}
+	for _, evType := range [3]fs.EventType{fs.NonRemove, fs.Mixed, fs.Remove} {
+		currBatch := separatedBatches[evType]
+		if len(currBatch) != 0 {
+			select {
+			case out <- currBatch:
+			case <-a.ctx.Done():
+				return
+			}
+		}
+	}
+	// If sending to channel blocked for a long time,
+	// shorten next notifyDelay accordingly.
+	duration := time.Since(timeBeforeSending)
+	buffer := time.Millisecond
+	var nextDelay time.Duration
+	switch {
+	case duration < a.notifyDelay/10:
+		nextDelay = a.notifyDelay
+	case duration+buffer > a.notifyDelay:
+		nextDelay = buffer
+	default:
+		nextDelay = a.notifyDelay - duration
+	}
+	select {
+	case a.notifyTimerResetChan <- nextDelay:
+	case <-a.ctx.Done():
+	}
+}
+
+// popOldEvents finds events that should be scheduled for scanning recursively in dirs,
+// removes those events and empty eventDirs and returns a map with all the removed
+// events referenced by their filesystem path
+func (a *aggregator) popOldEvents(dir *eventDir, dirPath string, currTime time.Time) map[string]*aggregatedEvent {
+	oldEvents := make(map[string]*aggregatedEvent)
+	for childName, childDir := range dir.dirs {
+		for evPath, event := range a.popOldEvents(childDir, filepath.Join(dirPath, childName), currTime) {
+			oldEvents[evPath] = event
+		}
+		if childDir.childCount() == 0 {
+			delete(dir.dirs, childName)
+		}
+	}
+	for name, event := range dir.events {
+		if a.isOld(event, currTime) {
+			oldEvents[filepath.Join(dirPath, name)] = event
+			delete(dir.events, name)
+		}
+	}
+	return oldEvents
+}
+
+func (a *aggregator) isOld(ev *aggregatedEvent, currTime time.Time) bool {
+	// Deletes should always be scanned last, therefore they are always
+	// delayed by letting them time out (see below).
+	// An event that has not registered any new modifications recently is scanned.
+	// a.notifyDelay is the user facing value signifying the normal delay between
+	// a picking up a modification and scanning it. As scheduling scans happens at
+	// regular intervals of a.notifyDelay the delay of a single event is not exactly
+	// a.notifyDelay, but lies in in the range of 0.5 to 1.5 times a.notifyDelay.
+	if ev.evType == fs.NonRemove && 2*currTime.Sub(ev.lastModTime) > a.notifyDelay {
+		return true
+	}
+	// When an event registers repeat modifications or involves removals it
+	// is delayed to reduce resource usage, but after a certain time (notifyTimeout)
+	// passed it is scanned anyway.
+	return currTime.Sub(ev.firstModTime) > a.notifyTimeout
+}
+
+func (a *aggregator) String() string {
+	return fmt.Sprintf("aggregator/%s:", a.folderCfg.Description())
+}
+
+func (a *aggregator) VerifyConfiguration(from, to config.Configuration) error {
+	return nil
+}
+
+func (a *aggregator) CommitConfiguration(from, to config.Configuration) bool {
+	for _, folderCfg := range to.Folders {
+		if folderCfg.ID == a.folderCfg.ID {
+			select {
+			case a.folderCfgUpdate <- folderCfg:
+			case <-a.ctx.Done():
+			}
+			return true
+		}
+	}
+	// Nothing to do, model will soon stop this
+	return true
+}
+
+func (a *aggregator) updateConfig(folderCfg config.FolderConfiguration) {
+	a.notifyDelay = time.Duration(folderCfg.FSWatcherDelayS) * time.Second
+	a.notifyTimeout = notifyTimeout(folderCfg.FSWatcherDelayS)
+	a.folderCfg = folderCfg
+}
+
+func updateInProgressSet(event events.Event, inProgress map[string]struct{}) {
+	if event.Type == events.ItemStarted {
+		path := event.Data.(map[string]string)["item"]
+		inProgress[path] = struct{}{}
+	} else if event.Type == events.ItemFinished {
+		path := event.Data.(map[string]interface{})["item"].(string)
+		delete(inProgress, path)
+	}
+}
+
+// Events that involve removals or continuously receive new modifications are
+// delayed but must time out at some point. The following numbers come out of thin
+// air, they were just considered as a sensible compromise between fast updates and
+// saving resources. For short delays the timeout is 6 times the delay, capped at 1
+// minute. For delays longer than 1 minute, the delay and timeout are equal.
+func notifyTimeout(eventDelayS int) time.Duration {
+	shortDelayS := 10
+	shortDelayMultiplicator := 6
+	longDelayS := 60
+	longDelayTimeout := time.Duration(1) * time.Minute
+	if eventDelayS < shortDelayS {
+		return time.Duration(eventDelayS*shortDelayMultiplicator) * time.Second
+	}
+	if eventDelayS < longDelayS {
+		return longDelayTimeout
+	}
+	return time.Duration(eventDelayS) * time.Second
+}

lib/watchaggregator/aggregator_test.go

@@ -0,0 +1,281 @@
+// Copyright (C) 2016 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package watchaggregator
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"strconv"
+	"testing"
+	"time"
+
+	"github.com/syncthing/syncthing/lib/config"
+	"github.com/syncthing/syncthing/lib/events"
+	"github.com/syncthing/syncthing/lib/fs"
+)
+
+func TestMain(m *testing.M) {
+	maxFiles = 32
+	maxFilesPerDir = 8
+	defer func() {
+		maxFiles = 512
+		maxFilesPerDir = 128
+	}()
+
+	os.Exit(m.Run())
+}
+
+const (
+	testNotifyDelayS  = 1
+	testNotifyTimeout = 2 * time.Second
+)
+
+var (
+	folderRoot       = filepath.Clean("/home/someuser/syncthing")
+	defaultFolderCfg = config.FolderConfiguration{
+		FilesystemType:  fs.FilesystemTypeBasic,
+		Path:            folderRoot,
+		FSWatcherDelayS: testNotifyDelayS,
+	}
+	defaultCfg = config.Wrap("", config.Configuration{
+		Folders: []config.FolderConfiguration{defaultFolderCfg},
+	})
+)
+
+type expectedBatch struct {
+	paths    []string
+	afterMs  int
+	beforeMs int
+}
+
+// TestAggregate checks whether maxFilesPerDir+1 events in one dir are
+// aggregated to parent dir
+func TestAggregate(t *testing.T) {
+	evDir := newEventDir()
+	inProgress := make(map[string]struct{})
+
+	folderCfg := defaultFolderCfg.Copy()
+	folderCfg.ID = "Aggregate"
+	ctx, _ := context.WithCancel(context.Background())
+	a := new(folderCfg, ctx)
+
+	// checks whether maxFilesPerDir events in one dir are kept as is
+	for i := 0; i < maxFilesPerDir; i++ {
+		a.newEvent(fs.Event{filepath.Join("parent", strconv.Itoa(i)), fs.NonRemove}, evDir, inProgress)
+	}
+	if len(getEventPaths(evDir, ".", a)) != maxFilesPerDir {
+		t.Errorf("Unexpected number of events stored")
+	}
+
+	// checks whether maxFilesPerDir+1 events in one dir are aggregated to parent dir
+	a.newEvent(fs.Event{filepath.Join("parent", "new"), fs.NonRemove}, evDir, inProgress)
+	compareBatchToExpected(t, getEventPaths(evDir, ".", a), []string{"parent"})
+
+	// checks that adding an event below "parent" does not change anything
+	a.newEvent(fs.Event{filepath.Join("parent", "extra"), fs.NonRemove}, evDir, inProgress)
+	compareBatchToExpected(t, getEventPaths(evDir, ".", a), []string{"parent"})
+
+	// again test aggregation in "parent" but with event in subdirs
+	evDir = newEventDir()
+	for i := 0; i < maxFilesPerDir; i++ {
+		a.newEvent(fs.Event{filepath.Join("parent", strconv.Itoa(i)), fs.NonRemove}, evDir, inProgress)
+	}
+	a.newEvent(fs.Event{filepath.Join("parent", "sub", "new"), fs.NonRemove}, evDir, inProgress)
+	compareBatchToExpected(t, getEventPaths(evDir, ".", a), []string{"parent"})
+
+	// test aggregation in root
+	evDir = newEventDir()
+	for i := 0; i < maxFiles; i++ {
+		a.newEvent(fs.Event{strconv.Itoa(i), fs.NonRemove}, evDir, inProgress)
+	}
+	if len(getEventPaths(evDir, ".", a)) != maxFiles {
+		t.Errorf("Unexpected number of events stored in root")
+	}
+	a.newEvent(fs.Event{filepath.Join("parent", "sub", "new"), fs.NonRemove}, evDir, inProgress)
+	compareBatchToExpected(t, getEventPaths(evDir, ".", a), []string{"."})
+
+	// checks that adding an event when "." is already stored is a noop
+	a.newEvent(fs.Event{"anythingelse", fs.NonRemove}, evDir, inProgress)
+	compareBatchToExpected(t, getEventPaths(evDir, ".", a), []string{"."})
+
+	// TestOverflow checks that the entire folder is scanned when maxFiles is reached
+	evDir = newEventDir()
+	filesPerDir := maxFilesPerDir / 2
+	dirs := make([]string, maxFiles/filesPerDir+1)
+	for i := 0; i < maxFiles/filesPerDir+1; i++ {
+		dirs[i] = "dir" + strconv.Itoa(i)
+	}
+	for _, dir := range dirs {
+		for i := 0; i < filesPerDir; i++ {
+			a.newEvent(fs.Event{filepath.Join(dir, strconv.Itoa(i)), fs.NonRemove}, evDir, inProgress)
+		}
+	}
+	compareBatchToExpected(t, getEventPaths(evDir, ".", a), []string{"."})
+}
+
+// TestInProgress checks that ignoring files currently edited by Syncthing works
+func TestInProgress(t *testing.T) {
+	testCase := func(c chan<- fs.Event) {
+		events.Default.Log(events.ItemStarted, map[string]string{
+			"item": "inprogress",
+		})
+		sleepMs(100)
+		c <- fs.Event{Name: "inprogress", Type: fs.NonRemove}
+		sleepMs(1000)
+		events.Default.Log(events.ItemFinished, map[string]interface{}{
+			"item": "inprogress",
+		})
+		sleepMs(100)
+		c <- fs.Event{Name: "notinprogress", Type: fs.NonRemove}
+		sleepMs(800)
+	}
+
+	expectedBatches := []expectedBatch{
+		{[]string{"notinprogress"}, 2000, 3500},
+	}
+
+	testScenario(t, "InProgress", testCase, expectedBatches)
+}
+
+// TestDelay checks that recurring changes to the same path are delayed
+// and different types separated and ordered correctly
+func TestDelay(t *testing.T) {
+	file := filepath.Join("parent", "file")
+	delayed := "delayed"
+	del := "deleted"
+	both := filepath.Join("parent", "sub", "both")
+	testCase := func(c chan<- fs.Event) {
+		sleepMs(200)
+		c <- fs.Event{Name: file, Type: fs.NonRemove}
+		delay := time.Duration(300) * time.Millisecond
+		timer := time.NewTimer(delay)
+		<-timer.C
+		timer.Reset(delay)
+		c <- fs.Event{Name: delayed, Type: fs.NonRemove}
+		c <- fs.Event{Name: both, Type: fs.NonRemove}
+		c <- fs.Event{Name: both, Type: fs.Remove}
+		c <- fs.Event{Name: del, Type: fs.Remove}
+		for i := 0; i < 9; i++ {
+			<-timer.C
+			timer.Reset(delay)
+			c <- fs.Event{Name: delayed, Type: fs.NonRemove}
+		}
+		<-timer.C
+	}
+
+	// batches that we expect to receive with time interval in milliseconds
+	expectedBatches := []expectedBatch{
+		{[]string{file}, 500, 2500},
+		{[]string{delayed}, 2500, 4500},
+		{[]string{both}, 2500, 4500},
+		{[]string{del}, 2500, 4500},
+		{[]string{delayed}, 3600, 6500},
+	}
+
+	testScenario(t, "Delay", testCase, expectedBatches)
+}
+
+func getEventPaths(dir *eventDir, dirPath string, a *aggregator) []string {
+	var paths []string
+	for childName, childDir := range dir.dirs {
+		for _, path := range getEventPaths(childDir, filepath.Join(dirPath, childName), a) {
+			paths = append(paths, path)
+		}
+	}
+	for name := range dir.events {
+		paths = append(paths, filepath.Join(dirPath, name))
+	}
+	return paths
+}
+
+func sleepMs(ms int) {
+	time.Sleep(time.Duration(ms) * time.Millisecond)
+}
+
+func durationMs(ms int) time.Duration {
+	return time.Duration(ms) * time.Millisecond
+}
+
+func compareBatchToExpected(t *testing.T, batch []string, expectedPaths []string) {
+	for _, expected := range expectedPaths {
+		expected = filepath.Clean(expected)
+		found := false
+		for i, received := range batch {
+			if expected == received {
+				found = true
+				batch = append(batch[:i], batch[i+1:]...)
+				break
+			}
+		}
+		if !found {
+			t.Errorf("Did not receive event %s", expected)
+		}
+	}
+	for _, received := range batch {
+		t.Errorf("Received unexpected event %s", received)
+	}
+}
+
+func testScenario(t *testing.T, name string, testCase func(c chan<- fs.Event), expectedBatches []expectedBatch) {
+	ctx, cancel := context.WithCancel(context.Background())
+	eventChan := make(chan fs.Event)
+	watchChan := make(chan []string)
+
+	folderCfg := defaultFolderCfg.Copy()
+	folderCfg.ID = name
+	a := new(folderCfg, ctx)
+	a.notifyTimeout = testNotifyTimeout
+
+	startTime := time.Now()
+	go a.mainLoop(eventChan, watchChan, defaultCfg)
+
+	sleepMs(10)
+	go testAggregatorOutput(t, watchChan, expectedBatches, startTime, ctx)
+
+	testCase(eventChan)
+
+	timeout := time.NewTimer(time.Duration(expectedBatches[len(expectedBatches)-1].beforeMs+100) * time.Millisecond)
+	<-timeout.C
+	cancel()
+}
+
+func testAggregatorOutput(t *testing.T, fsWatchChan <-chan []string, expectedBatches []expectedBatch, startTime time.Time, ctx context.Context) {
+	var received []string
+	var elapsedTime time.Duration
+	batchIndex := 0
+	for {
+		select {
+		case <-ctx.Done():
+			if batchIndex != len(expectedBatches) {
+				t.Errorf("Received only %d batches (%d expected)", batchIndex, len(expectedBatches))
+			}
+			return
+		case received = <-fsWatchChan:
+		}
+
+		if batchIndex >= len(expectedBatches) {
+			t.Errorf("Received batch %d (only %d expected)", batchIndex+1, len(expectedBatches))
+			continue
+		}
+
+		elapsedTime = time.Since(startTime)
+		expected := expectedBatches[batchIndex]
+		switch {
+		case elapsedTime < durationMs(expected.afterMs):
+			t.Errorf("Received batch %d after %v (too soon)", batchIndex+1, elapsedTime)
+
+		case elapsedTime > durationMs(expected.beforeMs):
+			t.Errorf("Received batch %d after %v (too late)", batchIndex+1, elapsedTime)
+
+		case len(received) != len(expected.paths):
+			t.Errorf("Received %v events instead of %v for batch %v", len(received), len(expected.paths), batchIndex+1)
+		}
+		compareBatchToExpected(t, received, expected.paths)
+		batchIndex++
+	}
+}

lib/watchaggregator/debug.go

@@ -0,0 +1,24 @@
+// Copyright (C) 2016 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package watchaggregator
+
+import (
+	"os"
+	"strings"
+
+	"github.com/syncthing/syncthing/lib/logger"
+)
+
+var facilityName = "watchaggregator"
+
+var (
+	l = logger.DefaultLogger.NewFacility(facilityName, "Filesystem event watcher")
+)
+
+func init() {
+	l.SetDebug(facilityName, strings.Contains(os.Getenv("STTRACE"), facilityName) || os.Getenv("STTRACE") == "all")
+}

man/syncthing-rest-api.7

@@ -111,6 +111,7 @@ Returns the current configuration.
             }
           ],
           "rescanIntervalS": 60,
+          "longRescanIntervalS": 3600,
           "ignorePerms": false,
           "autoNormalize": true,
           "minDiskFreePct": 1,

vendor/github.com/zillode/notify/LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2014-2015 The Notify Authors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

vendor/github.com/zillode/notify/debug.go

@@ -0,0 +1,11 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build !debug
+
+package notify
+
+func dbgprint(...interface{}) {}
+
+func dbgprintf(string, ...interface{}) {}

vendor/github.com/zillode/notify/debug_debug.go

@@ -0,0 +1,43 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build debug
+
+package notify
+
+import (
+	"fmt"
+	"os"
+	"runtime"
+	"strings"
+)
+
+func dbgprint(v ...interface{}) {
+	fmt.Printf("[D] ")
+	fmt.Print(v...)
+	fmt.Printf("\n\n")
+}
+
+func dbgprintf(format string, v ...interface{}) {
+	fmt.Printf("[D] ")
+	fmt.Printf(format, v...)
+	fmt.Printf("\n\n")
+}
+
+func dbgcallstack(max int) []string {
+	pc, stack := make([]uintptr, max), make([]string, 0, max)
+	runtime.Callers(2, pc)
+	for _, pc := range pc {
+		if f := runtime.FuncForPC(pc); f != nil {
+			fname := f.Name()
+			idx := strings.LastIndex(fname, string(os.PathSeparator))
+			if idx != -1 {
+				stack = append(stack, fname[idx+1:])
+			} else {
+				stack = append(stack, fname)
+			}
+		}
+	}
+	return stack
+}

vendor/github.com/zillode/notify/doc.go

@@ -0,0 +1,43 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// Package notify implements access to filesystem events.
+//
+// Notify is a high-level abstraction over filesystem watchers like inotify,
+// kqueue, FSEvents, FEN or ReadDirectoryChangesW. Watcher implementations are
+// split into two groups: ones that natively support recursive notifications
+// (FSEvents and ReadDirectoryChangesW) and ones that do not (inotify, kqueue, FEN).
+// For more details see watcher and recursiveWatcher interfaces in watcher.go
+// source file.
+//
+// On top of filesystem watchers notify maintains a watchpoint tree, which provides
+// a strategy for creating and closing filesystem watches and dispatching filesystem
+// events to user channels.
+//
+// An event set is just an event list joint using bitwise OR operator
+// into a single event value.
+// Both the platform-independent (see Constants) and specific events can be used.
+// Refer to the event_*.go source files for information about the available
+// events.
+//
+// A filesystem watch or just a watch is platform-specific entity which represents
+// a single path registered for notifications for specific event set. Setting a watch
+// means using platform-specific API calls for creating / initializing said watch.
+// For each watcher the API call is:
+//
+//   - FSEvents: FSEventStreamCreate
+//   - inotify:  notify_add_watch
+//   - kqueue:   kevent
+//   - ReadDirectoryChangesW: CreateFile+ReadDirectoryChangesW
+//   - FEN:      port_get
+//
+// To rewatch means to either shrink or expand an event set that was previously
+// registered during watch operation for particular filesystem watch.
+//
+// A watchpoint is a list of user channel and event set pairs for particular
+// path (watchpoint tree's node). A single watchpoint can contain multiple
+// different user channels registered to listen for one or more events. A single
+// user channel can be registered in one or more watchpoints, recursive and
+// non-recursive ones as well.
+package notify

vendor/github.com/zillode/notify/event.go

@@ -0,0 +1,143 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+package notify
+
+import (
+	"fmt"
+	"strings"
+)
+
+// Event represents the type of filesystem action.
+//
+// Number of available event values is dependent on the target system or the
+// watcher implmenetation used (e.g. it's possible to use either kqueue or
+// FSEvents on Darwin).
+//
+// Please consult documentation for your target platform to see list of all
+// available events.
+type Event uint32
+
+// Create, Remove, Write and Rename are the only event values guaranteed to be
+// present on all platforms.
+const (
+	Create = osSpecificCreate
+	Remove = osSpecificRemove
+	Write  = osSpecificWrite
+	Rename = osSpecificRename
+
+	// All is handful alias for all platform-independent event values.
+	All = Create | Remove | Write | Rename
+)
+
+const internal = recursive | omit
+
+// String implements fmt.Stringer interface.
+func (e Event) String() string {
+	var s []string
+	for _, strmap := range []map[Event]string{estr, osestr} {
+		for ev, str := range strmap {
+			if e&ev == ev {
+				s = append(s, str)
+			}
+		}
+	}
+	return strings.Join(s, "|")
+}
+
+// EventInfo describes an event reported by the underlying filesystem notification
+// subsystem.
+//
+// It always describes single event, even if the OS reported a coalesced action.
+// Reported path is absolute and clean.
+//
+// For non-recursive watchpoints its base is always equal to the path passed
+// to corresponding Watch call.
+//
+// The value of Sys if system-dependent and can be nil.
+//
+// Sys
+//
+// Under Darwin (FSEvents) Sys() always returns a non-nil *notify.FSEvent value,
+// which is defined as:
+//
+//   type FSEvent struct {
+//       Path  string // real path of the file or directory
+//       ID    uint64 // ID of the event (FSEventStreamEventId)
+//       Flags uint32 // joint FSEvents* flags (FSEventStreamEventFlags)
+//   }
+//
+// For possible values of Flags see Darwin godoc for notify or FSEvents
+// documentation for FSEventStreamEventFlags constants:
+//
+//    https://developer.apple.com/library/mac/documentation/Darwin/Reference/FSEvents_Ref/index.html#//apple_ref/doc/constant_group/FSEventStreamEventFlags
+//
+// Under Linux (inotify) Sys() always returns a non-nil *unix.InotifyEvent
+// value, defined as:
+//
+//   type InotifyEvent struct {
+//       Wd     int32    // Watch descriptor
+//       Mask   uint32   // Mask describing event
+//       Cookie uint32   // Unique cookie associating related events (for rename(2))
+//       Len    uint32   // Size of name field
+//       Name   [0]uint8 // Optional null-terminated name
+//   }
+//
+// More information about inotify masks and the usage of inotify_event structure
+// can be found at:
+//
+//    http://man7.org/linux/man-pages/man7/inotify.7.html
+//
+// Under Darwin, DragonFlyBSD, FreeBSD, NetBSD, OpenBSD (kqueue) Sys() always
+// returns a non-nil *notify.Kevent value, which is defined as:
+//
+//   type Kevent struct {
+//       Kevent *syscall.Kevent_t // Kevent is a kqueue specific structure
+//       FI     os.FileInfo       // FI describes file/dir
+//   }
+//
+// More information about syscall.Kevent_t can be found at:
+//
+//    https://www.freebsd.org/cgi/man.cgi?query=kqueue
+//
+// Under Windows (ReadDirectoryChangesW) Sys() always returns nil. The documentation
+// of watcher's WinAPI function can be found at:
+//
+//    https://msdn.microsoft.com/en-us/library/windows/desktop/aa365465%28v=vs.85%29.aspx
+type EventInfo interface {
+	Event() Event     // event value for the filesystem action
+	Path() string     // real path of the file or directory
+	Sys() interface{} // underlying data source (can return nil)
+}
+
+type isDirer interface {
+	isDir() (bool, error)
+}
+
+var _ fmt.Stringer = (*event)(nil)
+var _ isDirer = (*event)(nil)
+
+// String implements fmt.Stringer interface.
+func (e *event) String() string {
+	return e.Event().String() + `: "` + e.Path() + `"`
+}
+
+var estr = map[Event]string{
+	Create: "notify.Create",
+	Remove: "notify.Remove",
+	Write:  "notify.Write",
+	Rename: "notify.Rename",
+	// Display name for recursive event is added only for debugging
+	// purposes. It's an internal event after all and won't be exposed to the
+	// user. Having Recursive event printable is helpful, e.g. for reading
+	// testing failure messages:
+	//
+	//    --- FAIL: TestWatchpoint (0.00 seconds)
+	//    watchpoint_test.go:64: want diff=[notify.Remove notify.Create|notify.Remove];
+	//    got [notify.Remove notify.Remove|notify.Create] (i=1)
+	//
+	// Yup, here the diff have Recursive event inside. Go figure.
+	recursive: "recursive",
+	omit:      "omit",
+}

vendor/github.com/zillode/notify/event_fen.go

@@ -0,0 +1,57 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build solaris
+
+package notify
+
+const (
+	osSpecificCreate Event = 0x00000100 << iota
+	osSpecificRemove
+	osSpecificWrite
+	osSpecificRename
+	// internal
+	// recursive is used to distinguish recursive eventsets from non-recursive ones
+	recursive
+	// omit is used for dispatching internal events; only those events are sent
+	// for which both the event and the watchpoint has omit in theirs event sets.
+	omit
+)
+
+const (
+	// FileAccess is an event reported when monitored file/directory was accessed.
+	FileAccess = fileAccess
+	// FileModified is an event reported when monitored file/directory was modified.
+	FileModified = fileModified
+	// FileAttrib is an event reported when monitored file/directory's ATTRIB
+	// was changed.
+	FileAttrib = fileAttrib
+	// FileDelete is an event reported when monitored file/directory was deleted.
+	FileDelete = fileDelete
+	// FileRenameTo to is an event reported when monitored file/directory was renamed.
+	FileRenameTo = fileRenameTo
+	// FileRenameFrom is an event reported when monitored file/directory was renamed.
+	FileRenameFrom = fileRenameFrom
+	// FileTrunc is an event reported when monitored file/directory was truncated.
+	FileTrunc = fileTrunc
+	// FileNoFollow is an flag to indicate not to follow symbolic links.
+	FileNoFollow = fileNoFollow
+	// Unmounted is an event reported when monitored filesystem was unmounted.
+	Unmounted = unmounted
+	// MountedOver is an event reported when monitored file/directory was mounted on.
+	MountedOver = mountedOver
+)
+
+var osestr = map[Event]string{
+	FileAccess:     "notify.FileAccess",
+	FileModified:   "notify.FileModified",
+	FileAttrib:     "notify.FileAttrib",
+	FileDelete:     "notify.FileDelete",
+	FileRenameTo:   "notify.FileRenameTo",
+	FileRenameFrom: "notify.FileRenameFrom",
+	FileTrunc:      "notify.FileTrunc",
+	FileNoFollow:   "notify.FileNoFollow",
+	Unmounted:      "notify.Unmounted",
+	MountedOver:    "notify.MountedOver",
+}

vendor/github.com/zillode/notify/event_fsevents.go

@@ -0,0 +1,71 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build darwin,!kqueue
+
+package notify
+
+const (
+	osSpecificCreate = Event(FSEventsCreated)
+	osSpecificRemove = Event(FSEventsRemoved)
+	osSpecificWrite  = Event(FSEventsModified)
+	osSpecificRename = Event(FSEventsRenamed)
+	// internal = Event(0x100000)
+	// recursive is used to distinguish recursive eventsets from non-recursive ones
+	recursive = Event(0x200000)
+	// omit is used for dispatching internal events; only those events are sent
+	// for which both the event and the watchpoint has omit in theirs event sets.
+	omit = Event(0x400000)
+)
+
+// FSEvents specific event values.
+const (
+	FSEventsMustScanSubDirs Event = 0x00001
+	FSEventsUserDropped           = 0x00002
+	FSEventsKernelDropped         = 0x00004
+	FSEventsEventIdsWrapped       = 0x00008
+	FSEventsHistoryDone           = 0x00010
+	FSEventsRootChanged           = 0x00020
+	FSEventsMount                 = 0x00040
+	FSEventsUnmount               = 0x00080
+	FSEventsCreated               = 0x00100
+	FSEventsRemoved               = 0x00200
+	FSEventsInodeMetaMod          = 0x00400
+	FSEventsRenamed               = 0x00800
+	FSEventsModified              = 0x01000
+	FSEventsFinderInfoMod         = 0x02000
+	FSEventsChangeOwner           = 0x04000
+	FSEventsXattrMod              = 0x08000
+	FSEventsIsFile                = 0x10000
+	FSEventsIsDir                 = 0x20000
+	FSEventsIsSymlink             = 0x40000
+)
+
+var osestr = map[Event]string{
+	FSEventsMustScanSubDirs: "notify.FSEventsMustScanSubDirs",
+	FSEventsUserDropped:     "notify.FSEventsUserDropped",
+	FSEventsKernelDropped:   "notify.FSEventsKernelDropped",
+	FSEventsEventIdsWrapped: "notify.FSEventsEventIdsWrapped",
+	FSEventsHistoryDone:     "notify.FSEventsHistoryDone",
+	FSEventsRootChanged:     "notify.FSEventsRootChanged",
+	FSEventsMount:           "notify.FSEventsMount",
+	FSEventsUnmount:         "notify.FSEventsUnmount",
+	FSEventsInodeMetaMod:    "notify.FSEventsInodeMetaMod",
+	FSEventsFinderInfoMod:   "notify.FSEventsFinderInfoMod",
+	FSEventsChangeOwner:     "notify.FSEventsChangeOwner",
+	FSEventsXattrMod:        "notify.FSEventsXattrMod",
+	FSEventsIsFile:          "notify.FSEventsIsFile",
+	FSEventsIsDir:           "notify.FSEventsIsDir",
+	FSEventsIsSymlink:       "notify.FSEventsIsSymlink",
+}
+
+type event struct {
+	fse   FSEvent
+	event Event
+}
+
+func (ei *event) Event() Event         { return ei.event }
+func (ei *event) Path() string         { return ei.fse.Path }
+func (ei *event) Sys() interface{}     { return &ei.fse }
+func (ei *event) isDir() (bool, error) { return ei.fse.Flags&FSEventsIsDir != 0, nil }

vendor/github.com/zillode/notify/event_inotify.go

@@ -0,0 +1,75 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build linux
+
+package notify
+
+import "golang.org/x/sys/unix"
+
+// Platform independent event values.
+const (
+	osSpecificCreate Event = 0x100000 << iota
+	osSpecificRemove
+	osSpecificWrite
+	osSpecificRename
+	// internal
+	// recursive is used to distinguish recursive eventsets from non-recursive ones
+	recursive
+	// omit is used for dispatching internal events; only those events are sent
+	// for which both the event and the watchpoint has omit in theirs event sets.
+	omit
+)
+
+// Inotify specific masks are legal, implemented events that are guaranteed to
+// work with notify package on linux-based systems.
+const (
+	InAccess       = Event(unix.IN_ACCESS)        // File was accessed
+	InModify       = Event(unix.IN_MODIFY)        // File was modified
+	InAttrib       = Event(unix.IN_ATTRIB)        // Metadata changed
+	InCloseWrite   = Event(unix.IN_CLOSE_WRITE)   // Writtable file was closed
+	InCloseNowrite = Event(unix.IN_CLOSE_NOWRITE) // Unwrittable file closed
+	InOpen         = Event(unix.IN_OPEN)          // File was opened
+	InMovedFrom    = Event(unix.IN_MOVED_FROM)    // File was moved from X
+	InMovedTo      = Event(unix.IN_MOVED_TO)      // File was moved to Y
+	InCreate       = Event(unix.IN_CREATE)        // Subfile was created
+	InDelete       = Event(unix.IN_DELETE)        // Subfile was deleted
+	InDeleteSelf   = Event(unix.IN_DELETE_SELF)   // Self was deleted
+	InMoveSelf     = Event(unix.IN_MOVE_SELF)     // Self was moved
+)
+
+var osestr = map[Event]string{
+	InAccess:       "notify.InAccess",
+	InModify:       "notify.InModify",
+	InAttrib:       "notify.InAttrib",
+	InCloseWrite:   "notify.InCloseWrite",
+	InCloseNowrite: "notify.InCloseNowrite",
+	InOpen:         "notify.InOpen",
+	InMovedFrom:    "notify.InMovedFrom",
+	InMovedTo:      "notify.InMovedTo",
+	InCreate:       "notify.InCreate",
+	InDelete:       "notify.InDelete",
+	InDeleteSelf:   "notify.InDeleteSelf",
+	InMoveSelf:     "notify.InMoveSelf",
+}
+
+// Inotify behavior events are not **currently** supported by notify package.
+const (
+	inDontFollow = Event(unix.IN_DONT_FOLLOW)
+	inExclUnlink = Event(unix.IN_EXCL_UNLINK)
+	inMaskAdd    = Event(unix.IN_MASK_ADD)
+	inOneshot    = Event(unix.IN_ONESHOT)
+	inOnlydir    = Event(unix.IN_ONLYDIR)
+)
+
+type event struct {
+	sys   unix.InotifyEvent
+	path  string
+	event Event
+}
+
+func (e *event) Event() Event         { return e.event }
+func (e *event) Path() string         { return e.path }
+func (e *event) Sys() interface{}     { return &e.sys }
+func (e *event) isDir() (bool, error) { return e.sys.Mask&unix.IN_ISDIR != 0, nil }

vendor/github.com/zillode/notify/event_kqueue.go

@@ -0,0 +1,59 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build darwin,kqueue dragonfly freebsd netbsd openbsd
+
+package notify
+
+import "syscall"
+
+// TODO(pblaszczyk): ensure in runtime notify built-in event values do not
+// overlap with platform-defined ones.
+
+// Platform independent event values.
+const (
+	osSpecificCreate Event = 0x0100 << iota
+	osSpecificRemove
+	osSpecificWrite
+	osSpecificRename
+	// internal
+	// recursive is used to distinguish recursive eventsets from non-recursive ones
+	recursive
+	// omit is used for dispatching internal events; only those events are sent
+	// for which both the event and the watchpoint has omit in theirs event sets.
+	omit
+)
+
+const (
+	// NoteDelete is an event reported when the unlink() system call was called
+	// on the file referenced by the descriptor.
+	NoteDelete = Event(syscall.NOTE_DELETE)
+	// NoteWrite is an event reported when a write occurred on the file
+	// referenced by the descriptor.
+	NoteWrite = Event(syscall.NOTE_WRITE)
+	// NoteExtend is an event reported when the file referenced by the
+	// descriptor was extended.
+	NoteExtend = Event(syscall.NOTE_EXTEND)
+	// NoteAttrib is an event reported when the file referenced
+	// by the descriptor had its attributes changed.
+	NoteAttrib = Event(syscall.NOTE_ATTRIB)
+	// NoteLink is an event reported when the link count on the file changed.
+	NoteLink = Event(syscall.NOTE_LINK)
+	// NoteRename is an event reported when the file referenced
+	// by the descriptor was renamed.
+	NoteRename = Event(syscall.NOTE_RENAME)
+	// NoteRevoke is an event reported when access to the file was revoked via
+	// revoke(2) or	the underlying file system was unmounted.
+	NoteRevoke = Event(syscall.NOTE_REVOKE)
+)
+
+var osestr = map[Event]string{
+	NoteDelete: "notify.NoteDelete",
+	NoteWrite:  "notify.NoteWrite",
+	NoteExtend: "notify.NoteExtend",
+	NoteAttrib: "notify.NoteAttrib",
+	NoteLink:   "notify.NoteLink",
+	NoteRename: "notify.NoteRename",
+	NoteRevoke: "notify.NoteRevoke",
+}

vendor/github.com/zillode/notify/event_readdcw.go

@@ -0,0 +1,118 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build windows
+
+package notify
+
+import (
+	"os"
+	"path/filepath"
+	"syscall"
+)
+
+// Platform independent event values.
+const (
+	osSpecificCreate Event = 1 << (20 + iota)
+	osSpecificRemove
+	osSpecificWrite
+	osSpecificRename
+	// recursive is used to distinguish recursive eventsets from non-recursive ones
+	recursive
+	// omit is used for dispatching internal events; only those events are sent
+	// for which both the event and the watchpoint has omit in theirs event sets.
+	omit
+	// dirmarker TODO(pknap)
+	dirmarker
+)
+
+// ReadDirectoryChangesW filters
+// On Windows the following events can be passed to Watch. A different set of
+// events (see actions below) are received on the channel passed to Watch.
+// For more information refer to
+// https://msdn.microsoft.com/en-us/library/windows/desktop/aa365465(v=vs.85).aspx
+const (
+	FileNotifyChangeFileName   = Event(syscall.FILE_NOTIFY_CHANGE_FILE_NAME)
+	FileNotifyChangeDirName    = Event(syscall.FILE_NOTIFY_CHANGE_DIR_NAME)
+	FileNotifyChangeAttributes = Event(syscall.FILE_NOTIFY_CHANGE_ATTRIBUTES)
+	FileNotifyChangeSize       = Event(syscall.FILE_NOTIFY_CHANGE_SIZE)
+	FileNotifyChangeLastWrite  = Event(syscall.FILE_NOTIFY_CHANGE_LAST_WRITE)
+	FileNotifyChangeLastAccess = Event(syscall.FILE_NOTIFY_CHANGE_LAST_ACCESS)
+	FileNotifyChangeCreation   = Event(syscall.FILE_NOTIFY_CHANGE_CREATION)
+	FileNotifyChangeSecurity   = Event(syscallFileNotifyChangeSecurity)
+)
+
+const (
+	fileNotifyChangeAll      = 0x17f // logical sum of all FileNotifyChange* events.
+	fileNotifyChangeModified = fileNotifyChangeAll &^ (FileNotifyChangeFileName | FileNotifyChangeDirName)
+)
+
+// according to: http://msdn.microsoft.com/en-us/library/windows/desktop/aa365465(v=vs.85).aspx
+// this flag should be declared in: http://golang.org/src/pkg/syscall/ztypes_windows.go
+const syscallFileNotifyChangeSecurity = 0x00000100
+
+// ReadDirectoryChangesW actions
+// The following events are returned on the channel passed to Watch, but cannot
+// be passed to Watch itself (see filters above). You can find a table showing
+// the relation between actions and filteres at
+// https://github.com/rjeczalik/notify/issues/10#issuecomment-66179535
+// The msdn documentation on actions is part of
+// https://msdn.microsoft.com/en-us/library/windows/desktop/aa364391(v=vs.85).aspx
+const (
+	FileActionAdded          = Event(syscall.FILE_ACTION_ADDED) << 12
+	FileActionRemoved        = Event(syscall.FILE_ACTION_REMOVED) << 12
+	FileActionModified       = Event(syscall.FILE_ACTION_MODIFIED) << 14
+	FileActionRenamedOldName = Event(syscall.FILE_ACTION_RENAMED_OLD_NAME) << 15
+	FileActionRenamedNewName = Event(syscall.FILE_ACTION_RENAMED_NEW_NAME) << 16
+)
+
+const fileActionAll = 0x7f000 // logical sum of all FileAction* events.
+
+var osestr = map[Event]string{
+	FileNotifyChangeFileName:   "notify.FileNotifyChangeFileName",
+	FileNotifyChangeDirName:    "notify.FileNotifyChangeDirName",
+	FileNotifyChangeAttributes: "notify.FileNotifyChangeAttributes",
+	FileNotifyChangeSize:       "notify.FileNotifyChangeSize",
+	FileNotifyChangeLastWrite:  "notify.FileNotifyChangeLastWrite",
+	FileNotifyChangeLastAccess: "notify.FileNotifyChangeLastAccess",
+	FileNotifyChangeCreation:   "notify.FileNotifyChangeCreation",
+	FileNotifyChangeSecurity:   "notify.FileNotifyChangeSecurity",
+
+	FileActionAdded:          "notify.FileActionAdded",
+	FileActionRemoved:        "notify.FileActionRemoved",
+	FileActionModified:       "notify.FileActionModified",
+	FileActionRenamedOldName: "notify.FileActionRenamedOldName",
+	FileActionRenamedNewName: "notify.FileActionRenamedNewName",
+}
+
+const (
+	fTypeUnknown uint8 = iota
+	fTypeFile
+	fTypeDirectory
+)
+
+// TODO(ppknap) : doc.
+type event struct {
+	pathw  []uint16
+	name   string
+	ftype  uint8
+	action uint32
+	filter uint32
+	e      Event
+}
+
+func (e *event) Event() Event     { return e.e }
+func (e *event) Path() string     { return filepath.Join(syscall.UTF16ToString(e.pathw), e.name) }
+func (e *event) Sys() interface{} { return e.ftype }
+
+func (e *event) isDir() (bool, error) {
+	if e.ftype != fTypeUnknown {
+		return e.ftype == fTypeDirectory, nil
+	}
+	fi, err := os.Stat(e.Path())
+	if err != nil {
+		return false, err
+	}
+	return fi.IsDir(), nil
+}

vendor/github.com/zillode/notify/event_stub.go

@@ -0,0 +1,31 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build !darwin,!linux,!freebsd,!dragonfly,!netbsd,!openbsd,!windows
+// +build !kqueue,!solaris
+
+package notify
+
+// Platform independent event values.
+const (
+	osSpecificCreate Event = 1 << iota
+	osSpecificRemove
+	osSpecificWrite
+	osSpecificRename
+	// internal
+	// recursive is used to distinguish recursive eventsets from non-recursive ones
+	recursive
+	// omit is used for dispatching internal events; only those events are sent
+	// for which both the event and the watchpoint has omit in theirs event sets.
+	omit
+)
+
+var osestr = map[Event]string{}
+
+type event struct{}
+
+func (e *event) Event() (_ Event)         { return }
+func (e *event) Path() (_ string)         { return }
+func (e *event) Sys() (_ interface{})     { return }
+func (e *event) isDir() (_ bool, _ error) { return }

vendor/github.com/zillode/notify/event_trigger.go

@@ -0,0 +1,22 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build darwin,kqueue dragonfly freebsd netbsd openbsd solaris
+
+package notify
+
+type event struct {
+	p  string
+	e  Event
+	d  bool
+	pe interface{}
+}
+
+func (e *event) Event() Event { return e.e }
+
+func (e *event) Path() string { return e.p }
+
+func (e *event) Sys() interface{} { return e.pe }
+
+func (e *event) isDir() (bool, error) { return e.d, nil }

vendor/github.com/zillode/notify/node.go

@@ -0,0 +1,272 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+package notify
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+)
+
+var errSkip = errors.New("notify: skip")
+
+type walkPathFunc func(nd node, isbase bool) error
+
+type walkFunc func(node) error
+
+func errnotexist(name string) error {
+	return &os.PathError{
+		Op:   "Node",
+		Path: name,
+		Err:  os.ErrNotExist,
+	}
+}
+
+type node struct {
+	Name  string
+	Watch watchpoint
+	Child map[string]node
+}
+
+func newnode(name string) node {
+	return node{
+		Name:  name,
+		Watch: make(watchpoint),
+		Child: make(map[string]node),
+	}
+}
+
+func (nd node) addchild(name, base string) node {
+	child, ok := nd.Child[base]
+	if !ok {
+		child = newnode(name)
+		nd.Child[base] = child
+	}
+	return child
+}
+
+func (nd node) Add(name string) node {
+	i := indexbase(nd.Name, name)
+	if i == -1 {
+		return node{}
+	}
+	for j := indexSep(name[i:]); j != -1; j = indexSep(name[i:]) {
+		nd = nd.addchild(name[:i+j], name[i:i+j])
+		i += j + 1
+	}
+	return nd.addchild(name, name[i:])
+}
+
+func (nd node) AddDir(fn walkFunc) error {
+	stack := []node{nd}
+Traverse:
+	for n := len(stack); n != 0; n = len(stack) {
+		nd, stack = stack[n-1], stack[:n-1]
+		switch err := fn(nd); err {
+		case nil:
+		case errSkip:
+			continue Traverse
+		default:
+			return fmt.Errorf("error while traversing %q: %v", nd.Name, err)
+		}
+		// TODO(rjeczalik): tolerate open failures - add failed names to
+		// AddDirError and notify users which names are not added to the tree.
+		fi, err := ioutil.ReadDir(nd.Name)
+		if err != nil {
+			return err
+		}
+		for _, fi := range fi {
+			if fi.Mode()&(os.ModeSymlink|os.ModeDir) == os.ModeDir {
+				name := filepath.Join(nd.Name, fi.Name())
+				stack = append(stack, nd.addchild(name, name[len(nd.Name)+1:]))
+			}
+		}
+	}
+	return nil
+}
+
+func (nd node) Get(name string) (node, error) {
+	i := indexbase(nd.Name, name)
+	if i == -1 {
+		return node{}, errnotexist(name)
+	}
+	ok := false
+	for j := indexSep(name[i:]); j != -1; j = indexSep(name[i:]) {
+		if nd, ok = nd.Child[name[i:i+j]]; !ok {
+			return node{}, errnotexist(name)
+		}
+		i += j + 1
+	}
+	if nd, ok = nd.Child[name[i:]]; !ok {
+		return node{}, errnotexist(name)
+	}
+	return nd, nil
+}
+
+func (nd node) Del(name string) error {
+	i := indexbase(nd.Name, name)
+	if i == -1 {
+		return errnotexist(name)
+	}
+	stack := []node{nd}
+	ok := false
+	for j := indexSep(name[i:]); j != -1; j = indexSep(name[i:]) {
+		if nd, ok = nd.Child[name[i:i+j]]; !ok {
+			return errnotexist(name[:i+j])
+		}
+		stack = append(stack, nd)
+	}
+	if nd, ok = nd.Child[name[i:]]; !ok {
+		return errnotexist(name)
+	}
+	nd.Child = nil
+	nd.Watch = nil
+	for name, i = base(nd.Name), len(stack); i != 0; name, i = base(nd.Name), i-1 {
+		nd = stack[i-1]
+		if nd := nd.Child[name]; len(nd.Watch) > 1 || len(nd.Child) != 0 {
+			break
+		} else {
+			nd.Child = nil
+			nd.Watch = nil
+		}
+		delete(nd.Child, name)
+	}
+	return nil
+}
+
+func (nd node) Walk(fn walkFunc) error {
+	stack := []node{nd}
+Traverse:
+	for n := len(stack); n != 0; n = len(stack) {
+		nd, stack = stack[n-1], stack[:n-1]
+		switch err := fn(nd); err {
+		case nil:
+		case errSkip:
+			continue Traverse
+		default:
+			return err
+		}
+		for name, nd := range nd.Child {
+			if name == "" {
+				// Node storing inactive watchpoints has empty name, skip it
+				// form traversing. Root node has also an empty name, but it
+				// never has a parent node.
+				continue
+			}
+			stack = append(stack, nd)
+		}
+	}
+	return nil
+}
+
+func (nd node) WalkPath(name string, fn walkPathFunc) error {
+	i := indexbase(nd.Name, name)
+	if i == -1 {
+		return errnotexist(name)
+	}
+	ok := false
+	for j := indexSep(name[i:]); j != -1; j = indexSep(name[i:]) {
+		switch err := fn(nd, false); err {
+		case nil:
+		case errSkip:
+			return nil
+		default:
+			return err
+		}
+		if nd, ok = nd.Child[name[i:i+j]]; !ok {
+			return errnotexist(name[:i+j])
+		}
+		i += j + 1
+	}
+	switch err := fn(nd, false); err {
+	case nil:
+	case errSkip:
+		return nil
+	default:
+		return err
+	}
+	if nd, ok = nd.Child[name[i:]]; !ok {
+		return errnotexist(name)
+	}
+	switch err := fn(nd, true); err {
+	case nil, errSkip:
+		return nil
+	default:
+		return err
+	}
+}
+
+type root struct {
+	nd node
+}
+
+func (r root) addroot(name string) node {
+	if vol := filepath.VolumeName(name); vol != "" {
+		root, ok := r.nd.Child[vol]
+		if !ok {
+			root = r.nd.addchild(vol, vol)
+		}
+		return root
+	}
+	return r.nd
+}
+
+func (r root) root(name string) (node, error) {
+	if vol := filepath.VolumeName(name); vol != "" {
+		nd, ok := r.nd.Child[vol]
+		if !ok {
+			return node{}, errnotexist(name)
+		}
+		return nd, nil
+	}
+	return r.nd, nil
+}
+
+func (r root) Add(name string) node {
+	return r.addroot(name).Add(name)
+}
+
+func (r root) AddDir(dir string, fn walkFunc) error {
+	return r.Add(dir).AddDir(fn)
+}
+
+func (r root) Del(name string) error {
+	nd, err := r.root(name)
+	if err != nil {
+		return err
+	}
+	return nd.Del(name)
+}
+
+func (r root) Get(name string) (node, error) {
+	nd, err := r.root(name)
+	if err != nil {
+		return node{}, err
+	}
+	if nd.Name != name {
+		if nd, err = nd.Get(name); err != nil {
+			return node{}, err
+		}
+	}
+	return nd, nil
+}
+
+func (r root) Walk(name string, fn walkFunc) error {
+	nd, err := r.Get(name)
+	if err != nil {
+		return err
+	}
+	return nd.Walk(fn)
+}
+
+func (r root) WalkPath(name string, fn walkPathFunc) error {
+	nd, err := r.root(name)
+	if err != nil {
+		return err
+	}
+	return nd.WalkPath(name, fn)
+}

vendor/github.com/zillode/notify/notify.go

@@ -0,0 +1,83 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// BUG(rjeczalik): Notify does not collect watchpoints, when underlying watches
+// were removed by their os-specific watcher implementations. Instead users are
+// advised to listen on persistent paths to have guarantee they receive events
+// for the whole lifetime of their applications (to discuss see #69).
+
+// BUG(ppknap): Linux (inotify) does not support watcher behavior masks like
+// InOneshot, InOnlydir etc. Instead users are advised to perform the filtering
+// themselves (to discuss see #71).
+
+// BUG(ppknap): Notify  was not tested for short path name support under Windows
+// (ReadDirectoryChangesW).
+
+// BUG(ppknap): Windows (ReadDirectoryChangesW) cannot recognize which notification
+// triggers FileActionModified event. (to discuss see #75).
+
+package notify
+
+var defaultTree = newTree()
+
+// Watch sets up a watchpoint on path listening for events given by the events
+// argument.
+//
+// File or directory given by the path must exist, otherwise Watch will fail
+// with non-nil error. Notify resolves, for its internal purpose, any symlinks
+// the provided path may contain, so it may fail if the symlinks form a cycle.
+// It does so, since not all watcher implementations treat passed paths as-is.
+// E.g. FSEvents reports a real path for every event, setting a watchpoint
+// on /tmp will report events with paths rooted at /private/tmp etc.
+//
+// The c almost always is a buffered channel. Watch will not block sending to c
+// - the caller must ensure that c has sufficient buffer space to keep up with
+// the expected event rate.
+//
+// It is allowed to pass the same channel multiple times with different event
+// list or different paths. Calling Watch with different event lists for a single
+// watchpoint expands its event set. The only way to shrink it, is to call
+// Stop on its channel.
+//
+// Calling Watch with empty event list does expand nor shrink watchpoint's event
+// set. If c is the first channel to listen for events on the given path, Watch
+// will seamlessly create a watch on the filesystem.
+//
+// Notify dispatches copies of single filesystem event to all channels registered
+// for each path. If a single filesystem event contains multiple coalesced events,
+// each of them is dispatched separately. E.g. the following filesystem change:
+//
+//   ~ $ echo Hello > Notify.txt
+//
+// dispatches two events - notify.Create and notify.Write. However, it may depend
+// on the underlying watcher implementation whether OS reports both of them.
+//
+// Windows and recursive watches
+//
+// If a directory which path was used to create recursive watch under Windows
+// gets deleted, the OS will not report such event. It is advised to keep in
+// mind this limitation while setting recursive watchpoints for your application,
+// e.g. use persistent paths like %userprofile% or watch additionally parent
+// directory of a recursive watchpoint in order to receive delete events for it.
+func Watch(path string, c chan<- EventInfo, events ...Event) error {
+	return defaultTree.Watch(path, c, nil, events...)
+}
+
+// This function works the same way as Watch. In addition it does not watch
+// files or directories based on the return value of the argument function
+// doNotWatch. Given a path as argument doNotWatch should return true if the
+// file or directory should not be watched.
+func WatchWithFilter(path string, c chan<- EventInfo,
+	doNotWatch func(string) bool, events ...Event) error {
+	return defaultTree.Watch(path, c, doNotWatch, events...)
+}
+
+// Stop removes all watchpoints registered for c. All underlying watches are
+// also removed, for which c was the last channel listening for events.
+//
+// Stop does not close c. When Stop returns, it is guaranteed that c will
+// receive no more signals.
+func Stop(c chan<- EventInfo) {
+	defaultTree.Stop(c)
+}

vendor/github.com/zillode/notify/tree.go

@@ -0,0 +1,22 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+package notify
+
+const buffer = 128
+
+type tree interface {
+	Watch(string, chan<- EventInfo, func(string) bool, ...Event) error
+	Stop(chan<- EventInfo)
+	Close() error
+}
+
+func newTree() tree {
+	c := make(chan EventInfo, buffer)
+	w := newWatcher(c)
+	if rw, ok := w.(recursiveWatcher); ok {
+		return newRecursiveTree(rw, c)
+	}
+	return newNonrecursiveTree(w, c, make(chan EventInfo, buffer))
+}

vendor/github.com/zillode/notify/tree_nonrecursive.go

@@ -0,0 +1,303 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+package notify
+
+import "sync"
+
+// nonrecursiveTree TODO(rjeczalik)
+type nonrecursiveTree struct {
+	rw   sync.RWMutex // protects root
+	root root
+	w    watcher
+	c    chan EventInfo
+	rec  chan EventInfo
+}
+
+// newNonrecursiveTree TODO(rjeczalik)
+func newNonrecursiveTree(w watcher, c, rec chan EventInfo) *nonrecursiveTree {
+	if rec == nil {
+		rec = make(chan EventInfo, buffer)
+	}
+	t := &nonrecursiveTree{
+		root: root{nd: newnode("")},
+		w:    w,
+		c:    c,
+		rec:  rec,
+	}
+	go t.dispatch(c)
+	go t.internal(rec)
+	return t
+}
+
+// dispatch TODO(rjeczalik)
+func (t *nonrecursiveTree) dispatch(c <-chan EventInfo) {
+	for ei := range c {
+		dbgprintf("dispatching %v on %q", ei.Event(), ei.Path())
+		go func(ei EventInfo) {
+			var nd node
+			var isrec bool
+			dir, base := split(ei.Path())
+			fn := func(it node, isbase bool) error {
+				isrec = isrec || it.Watch.IsRecursive()
+				if isbase {
+					nd = it
+				} else {
+					it.Watch.Dispatch(ei, recursive)
+				}
+				return nil
+			}
+			t.rw.RLock()
+			// Notify recursive watchpoints found on the path.
+			if err := t.root.WalkPath(dir, fn); err != nil {
+				dbgprint("dispatch did not reach leaf:", err)
+				t.rw.RUnlock()
+				return
+			}
+			// Notify parent watchpoint.
+			nd.Watch.Dispatch(ei, 0)
+			isrec = isrec || nd.Watch.IsRecursive()
+			// If leaf watchpoint exists, notify it.
+			if nd, ok := nd.Child[base]; ok {
+				isrec = isrec || nd.Watch.IsRecursive()
+				nd.Watch.Dispatch(ei, 0)
+			}
+			t.rw.RUnlock()
+			// If the event describes newly leaf directory created within
+			if !isrec || ei.Event() != Create {
+				return
+			}
+			if ok, err := ei.(isDirer).isDir(); !ok || err != nil {
+				return
+			}
+			t.rec <- ei
+		}(ei)
+	}
+}
+
+// internal TODO(rjeczalik)
+func (t *nonrecursiveTree) internal(rec <-chan EventInfo) {
+	for ei := range rec {
+		var nd node
+		var eset = internal
+		t.rw.Lock()
+		t.root.WalkPath(ei.Path(), func(it node, _ bool) error {
+			if e := it.Watch[t.rec]; e != 0 && e > eset {
+				eset = e
+			}
+			nd = it
+			return nil
+		})
+		if eset == internal {
+			t.rw.Unlock()
+			continue
+		}
+		err := nd.Add(ei.Path()).AddDir(t.recFunc(eset, nil))
+		t.rw.Unlock()
+		if err != nil {
+			dbgprintf("internal(%p) error: %v", rec, err)
+		}
+	}
+}
+
+// watchAdd TODO(rjeczalik)
+func (t *nonrecursiveTree) watchAdd(nd node, c chan<- EventInfo, e Event) eventDiff {
+	if e&recursive != 0 {
+		diff := nd.Watch.Add(t.rec, e|Create|omit)
+		nd.Watch.Add(c, e)
+		return diff
+	}
+	return nd.Watch.Add(c, e)
+}
+
+// watchDelMin TODO(rjeczalik)
+func (t *nonrecursiveTree) watchDelMin(min Event, nd node, c chan<- EventInfo, e Event) eventDiff {
+	old, ok := nd.Watch[t.rec]
+	if ok {
+		nd.Watch[t.rec] = min
+	}
+	diff := nd.Watch.Del(c, e)
+	if ok {
+		switch old &^= diff[0] &^ diff[1]; {
+		case old|internal == internal:
+			delete(nd.Watch, t.rec)
+			if set, ok := nd.Watch[nil]; ok && len(nd.Watch) == 1 && set == 0 {
+				delete(nd.Watch, nil)
+			}
+		default:
+			nd.Watch.Add(t.rec, old|Create)
+			switch {
+			case diff == none:
+			case diff[1]|Create == diff[0]:
+				diff = none
+			default:
+				diff[1] |= Create
+			}
+		}
+	}
+	return diff
+}
+
+// watchDel TODO(rjeczalik)
+func (t *nonrecursiveTree) watchDel(nd node, c chan<- EventInfo, e Event) eventDiff {
+	return t.watchDelMin(0, nd, c, e)
+}
+
+// Watch TODO(rjeczalik)
+func (t *nonrecursiveTree) Watch(path string, c chan<- EventInfo,
+	doNotWatch func(string) bool, events ...Event) error {
+	if c == nil {
+		panic("notify: Watch using nil channel")
+	}
+	// Expanding with empty event set is a nop.
+	if len(events) == 0 {
+		return nil
+	}
+	path, isrec, err := cleanpath(path)
+	if err != nil {
+		return err
+	}
+	eset := joinevents(events)
+	t.rw.Lock()
+	defer t.rw.Unlock()
+	nd := t.root.Add(path)
+	if isrec {
+		return t.watchrec(nd, c, eset|recursive, doNotWatch)
+	}
+	return t.watch(nd, c, eset)
+}
+
+func (t *nonrecursiveTree) watch(nd node, c chan<- EventInfo, e Event) (err error) {
+	diff := nd.Watch.Add(c, e)
+	switch {
+	case diff == none:
+		return nil
+	case diff[1] == 0:
+		// TODO(rjeczalik): cleanup this panic after implementation is stable
+		panic("eset is empty: " + nd.Name)
+	case diff[0] == 0:
+		err = t.w.Watch(nd.Name, diff[1])
+	default:
+		err = t.w.Rewatch(nd.Name, diff[0], diff[1])
+	}
+	if err != nil {
+		nd.Watch.Del(c, diff.Event())
+		return err
+	}
+	return nil
+}
+
+func (t *nonrecursiveTree) recFunc(e Event, doNotWatch func(string) bool) walkFunc {
+	addWatch := func(nd node) (err error) {
+		switch diff := nd.Watch.Add(t.rec, e|omit|Create); {
+		case diff == none:
+		case diff[1] == 0:
+			// TODO(rjeczalik): cleanup this panic after implementation is stable
+			panic("eset is empty: " + nd.Name)
+		case diff[0] == 0:
+			err = t.w.Watch(nd.Name, diff[1])
+		default:
+			err = t.w.Rewatch(nd.Name, diff[0], diff[1])
+		}
+		return
+	}
+	if doNotWatch != nil {
+		return func(nd node) (err error) {
+			if doNotWatch(nd.Name) {
+				return errSkip
+			}
+			return addWatch(nd)
+		}
+	}
+	return addWatch
+}
+
+func (t *nonrecursiveTree) watchrec(nd node, c chan<- EventInfo, e Event,
+	doNotWatch func(string) bool) error {
+	var traverse func(walkFunc) error
+	// Non-recursive tree listens on Create event for every recursive
+	// watchpoint in order to automagically set a watch for every
+	// created directory.
+	switch diff := nd.Watch.dryAdd(t.rec, e|Create); {
+	case diff == none:
+		t.watchAdd(nd, c, e)
+		nd.Watch.Add(t.rec, e|omit|Create)
+		return nil
+	case diff[1] == 0:
+		// TODO(rjeczalik): cleanup this panic after implementation is stable
+		panic("eset is empty: " + nd.Name)
+	case diff[0] == 0:
+		// TODO(rjeczalik): BFS into directories and skip subtree as soon as first
+		// recursive watchpoint is encountered.
+		traverse = nd.AddDir
+	default:
+		traverse = nd.Walk
+	}
+	// TODO(rjeczalik): account every path that failed to be (re)watched
+	// and retry.
+	if err := traverse(t.recFunc(e, doNotWatch)); err != nil {
+		return err
+	}
+	t.watchAdd(nd, c, e)
+	return nil
+}
+
+type walkWatchpointFunc func(Event, node) error
+
+func (t *nonrecursiveTree) walkWatchpoint(nd node, fn walkWatchpointFunc) error {
+	type minode struct {
+		min Event
+		nd  node
+	}
+	mnd := minode{nd: nd}
+	stack := []minode{mnd}
+Traverse:
+	for n := len(stack); n != 0; n = len(stack) {
+		mnd, stack = stack[n-1], stack[:n-1]
+		// There must be no recursive watchpoints if the node has no watchpoints
+		// itself (every node in subtree rooted at recursive watchpoints must
+		// have at least nil (total) and t.rec watchpoints).
+		if len(mnd.nd.Watch) != 0 {
+			switch err := fn(mnd.min, mnd.nd); err {
+			case nil:
+			case errSkip:
+				continue Traverse
+			default:
+				return err
+			}
+		}
+		for _, nd := range mnd.nd.Child {
+			stack = append(stack, minode{mnd.nd.Watch[t.rec], nd})
+		}
+	}
+	return nil
+}
+
+// Stop TODO(rjeczalik)
+func (t *nonrecursiveTree) Stop(c chan<- EventInfo) {
+	fn := func(min Event, nd node) error {
+		// TODO(rjeczalik): aggregate watcher errors and retry; in worst case
+		// forward to the user.
+		switch diff := t.watchDelMin(min, nd, c, all); {
+		case diff == none:
+			return nil
+		case diff[1] == 0:
+			t.w.Unwatch(nd.Name)
+		default:
+			t.w.Rewatch(nd.Name, diff[0], diff[1])
+		}
+		return nil
+	}
+	t.rw.Lock()
+	err := t.walkWatchpoint(t.root.nd, fn) // TODO(rjeczalik): store max root per c
+	t.rw.Unlock()
+	dbgprintf("Stop(%p) error: %v\n", c, err)
+}
+
+// Close TODO(rjeczalik)
+func (t *nonrecursiveTree) Close() error {
+	err := t.w.Close()
+	close(t.c)
+	return err
+}

vendor/github.com/zillode/notify/tree_recursive.go

@@ -0,0 +1,355 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+package notify
+
+import "sync"
+
+// watchAdd TODO(rjeczalik)
+func watchAdd(nd node, c chan<- EventInfo, e Event) eventDiff {
+	diff := nd.Watch.Add(c, e)
+	if wp := nd.Child[""].Watch; len(wp) != 0 {
+		e = wp.Total()
+		diff[0] |= e
+		diff[1] |= e
+		if diff[0] == diff[1] {
+			return none
+		}
+	}
+	return diff
+}
+
+// watchAddInactive TODO(rjeczalik)
+func watchAddInactive(nd node, c chan<- EventInfo, e Event) eventDiff {
+	wp := nd.Child[""].Watch
+	if wp == nil {
+		wp = make(watchpoint)
+		nd.Child[""] = node{Watch: wp}
+	}
+	diff := wp.Add(c, e)
+	e = nd.Watch.Total()
+	diff[0] |= e
+	diff[1] |= e
+	if diff[0] == diff[1] {
+		return none
+	}
+	return diff
+}
+
+// watchCopy TODO(rjeczalik)
+func watchCopy(src, dst node) {
+	for c, e := range src.Watch {
+		if c == nil {
+			continue
+		}
+		watchAddInactive(dst, c, e)
+	}
+	if wpsrc := src.Child[""].Watch; len(wpsrc) != 0 {
+		wpdst := dst.Child[""].Watch
+		for c, e := range wpsrc {
+			if c == nil {
+				continue
+			}
+			wpdst.Add(c, e)
+		}
+	}
+}
+
+// watchDel TODO(rjeczalik)
+func watchDel(nd node, c chan<- EventInfo, e Event) eventDiff {
+	diff := nd.Watch.Del(c, e)
+	if wp := nd.Child[""].Watch; len(wp) != 0 {
+		diffInactive := wp.Del(c, e)
+		e = wp.Total()
+		// TODO(rjeczalik): add e if e != all?
+		diff[0] |= diffInactive[0] | e
+		diff[1] |= diffInactive[1] | e
+		if diff[0] == diff[1] {
+			return none
+		}
+	}
+	return diff
+}
+
+// watchTotal TODO(rjeczalik)
+func watchTotal(nd node) Event {
+	e := nd.Watch.Total()
+	if wp := nd.Child[""].Watch; len(wp) != 0 {
+		e |= wp.Total()
+	}
+	return e
+}
+
+// watchIsRecursive TODO(rjeczalik)
+func watchIsRecursive(nd node) bool {
+	ok := nd.Watch.IsRecursive()
+	// TODO(rjeczalik): add a test for len(wp) != 0 change the condition.
+	if wp := nd.Child[""].Watch; len(wp) != 0 {
+		// If a watchpoint holds inactive watchpoints, it means it's a parent
+		// one, which is recursive by nature even though it may be not recursive
+		// itself.
+		ok = true
+	}
+	return ok
+}
+
+// recursiveTree TODO(rjeczalik)
+type recursiveTree struct {
+	rw   sync.RWMutex // protects root
+	root root
+	// TODO(rjeczalik): merge watcher + recursiveWatcher after #5 and #6
+	w interface {
+		watcher
+		recursiveWatcher
+	}
+	c chan EventInfo
+}
+
+// newRecursiveTree TODO(rjeczalik)
+func newRecursiveTree(w recursiveWatcher, c chan EventInfo) *recursiveTree {
+	t := &recursiveTree{
+		root: root{nd: newnode("")},
+		w: struct {
+			watcher
+			recursiveWatcher
+		}{w.(watcher), w},
+		c: c,
+	}
+	go t.dispatch()
+	return t
+}
+
+// dispatch TODO(rjeczalik)
+func (t *recursiveTree) dispatch() {
+	for ei := range t.c {
+		dbgprintf("dispatching %v on %q", ei.Event(), ei.Path())
+		go func(ei EventInfo) {
+			nd, ok := node{}, false
+			dir, base := split(ei.Path())
+			fn := func(it node, isbase bool) error {
+				if isbase {
+					nd = it
+				} else {
+					it.Watch.Dispatch(ei, recursive)
+				}
+				return nil
+			}
+			t.rw.RLock()
+			defer t.rw.RUnlock()
+			// Notify recursive watchpoints found on the path.
+			if err := t.root.WalkPath(dir, fn); err != nil {
+				dbgprint("dispatch did not reach leaf:", err)
+				return
+			}
+			// Notify parent watchpoint.
+			nd.Watch.Dispatch(ei, 0)
+			// If leaf watchpoint exists, notify it.
+			if nd, ok = nd.Child[base]; ok {
+				nd.Watch.Dispatch(ei, 0)
+			}
+		}(ei)
+	}
+}
+
+// Watch TODO(rjeczalik)
+func (t *recursiveTree) Watch(path string, c chan<- EventInfo,
+	doNotWatch func(string) bool, events ...Event) error {
+	if c == nil {
+		panic("notify: Watch using nil channel")
+	}
+	// Expanding with empty event set is a nop.
+	if len(events) == 0 {
+		return nil
+	}
+	path, isrec, err := cleanpath(path)
+	if err != nil {
+		return err
+	}
+	eventset := joinevents(events)
+	if isrec {
+		eventset |= recursive
+	}
+	t.rw.Lock()
+	defer t.rw.Unlock()
+	// case 1: cur is a child
+	//
+	// Look for parent watch which already covers the given path.
+	parent := node{}
+	self := false
+	err = t.root.WalkPath(path, func(nd node, isbase bool) error {
+		if watchTotal(nd) != 0 {
+			parent = nd
+			self = isbase
+			return errSkip
+		}
+		return nil
+	})
+	cur := t.root.Add(path) // add after the walk, so it's less to traverse
+	if err == nil && parent.Watch != nil {
+		// Parent watch found. Register inactive watchpoint, so we have enough
+		// information to shrink the eventset on eventual Stop.
+		// return t.resetwatchpoint(parent, parent, c, eventset|inactive)
+		var diff eventDiff
+		if self {
+			diff = watchAdd(cur, c, eventset)
+		} else {
+			diff = watchAddInactive(parent, c, eventset)
+		}
+		switch {
+		case diff == none:
+			// the parent watchpoint already covers requested subtree with its
+			// eventset
+		case diff[0] == 0:
+			// TODO(rjeczalik): cleanup this panic after implementation is stable
+			panic("dangling watchpoint: " + parent.Name)
+		default:
+			if isrec || watchIsRecursive(parent) {
+				err = t.w.RecursiveRewatch(parent.Name, parent.Name, diff[0], diff[1])
+			} else {
+				err = t.w.Rewatch(parent.Name, diff[0], diff[1])
+			}
+			if err != nil {
+				watchDel(parent, c, diff.Event())
+				return err
+			}
+			watchAdd(cur, c, eventset)
+			// TODO(rjeczalik): account top-most path for c
+			return nil
+		}
+		if !self {
+			watchAdd(cur, c, eventset)
+		}
+		return nil
+	}
+	// case 2: cur is new parent
+	//
+	// Look for children nodes, unwatch n-1 of them and rewatch the last one.
+	var children []node
+	fn := func(nd node) error {
+		if len(nd.Watch) == 0 {
+			return nil
+		}
+		children = append(children, nd)
+		return errSkip
+	}
+	switch must(cur.Walk(fn)); len(children) {
+	case 0:
+		// no child watches, cur holds a new watch
+	case 1:
+		watchAdd(cur, c, eventset) // TODO(rjeczalik): update cache c subtree root?
+		watchCopy(children[0], cur)
+		err = t.w.RecursiveRewatch(children[0].Name, cur.Name, watchTotal(children[0]),
+			watchTotal(cur))
+		if err != nil {
+			// Clean inactive watchpoint. The c chan did not exist before.
+			cur.Child[""] = node{}
+			delete(cur.Watch, c)
+			return err
+		}
+		return nil
+	default:
+		watchAdd(cur, c, eventset)
+		// Copy children inactive watchpoints to the new parent.
+		for _, nd := range children {
+			watchCopy(nd, cur)
+		}
+		// Watch parent subtree.
+		if err = t.w.RecursiveWatch(cur.Name, watchTotal(cur)); err != nil {
+			// Clean inactive watchpoint. The c chan did not exist before.
+			cur.Child[""] = node{}
+			delete(cur.Watch, c)
+			return err
+		}
+		// Unwatch children subtrees.
+		var e error
+		for _, nd := range children {
+			if watchIsRecursive(nd) {
+				e = t.w.RecursiveUnwatch(nd.Name)
+			} else {
+				e = t.w.Unwatch(nd.Name)
+			}
+			if e != nil {
+				err = nonil(err, e)
+				// TODO(rjeczalik): child is still watched, warn all its watchpoints
+				// about possible duplicate events via Error event
+			}
+		}
+		return err
+	}
+	// case 3: cur is new, alone node
+	switch diff := watchAdd(cur, c, eventset); {
+	case diff == none:
+		// TODO(rjeczalik): cleanup this panic after implementation is stable
+		panic("watch requested but no parent watchpoint found: " + cur.Name)
+	case diff[0] == 0:
+		if isrec {
+			err = t.w.RecursiveWatch(cur.Name, diff[1])
+		} else {
+			err = t.w.Watch(cur.Name, diff[1])
+		}
+		if err != nil {
+			watchDel(cur, c, diff.Event())
+			return err
+		}
+	default:
+		// TODO(rjeczalik): cleanup this panic after implementation is stable
+		panic("watch requested but no parent watchpoint found: " + cur.Name)
+	}
+	return nil
+}
+
+// Stop TODO(rjeczalik)
+//
+// TODO(rjeczalik): Split parent watchpoint - transfer watches to children
+// if parent is no longer needed. This carries a risk that underlying
+// watcher calls could fail - reconsider if it's worth the effort.
+func (t *recursiveTree) Stop(c chan<- EventInfo) {
+	var err error
+	fn := func(nd node) (e error) {
+		diff := watchDel(nd, c, all)
+		switch {
+		case diff == none && watchTotal(nd) == 0:
+			// TODO(rjeczalik): There's no watchpoints deeper in the tree,
+			// probably we should remove the nodes as well.
+			return nil
+		case diff == none:
+			// Removing c from nd does not require shrinking its eventset.
+		case diff[1] == 0:
+			if watchIsRecursive(nd) {
+				e = t.w.RecursiveUnwatch(nd.Name)
+			} else {
+				e = t.w.Unwatch(nd.Name)
+			}
+		default:
+			if watchIsRecursive(nd) {
+				e = t.w.RecursiveRewatch(nd.Name, nd.Name, diff[0], diff[1])
+			} else {
+				e = t.w.Rewatch(nd.Name, diff[0], diff[1])
+			}
+		}
+		fn := func(nd node) error {
+			watchDel(nd, c, all)
+			return nil
+		}
+		err = nonil(err, e, nd.Walk(fn))
+		// TODO(rjeczalik): if e != nil store dummy chan in nd.Watch just to
+		// retry un/rewatching next time and/or let the user handle the failure
+		// vie Error event?
+		return errSkip
+	}
+	t.rw.Lock()
+	e := t.root.Walk("", fn) // TODO(rjeczalik): use max root per c
+	t.rw.Unlock()
+	if e != nil {
+		err = nonil(err, e)
+	}
+	dbgprintf("Stop(%p) error: %v\n", c, err)
+}
+
+// Close TODO(rjeczalik)
+func (t *recursiveTree) Close() error {
+	err := t.w.Close()
+	close(t.c)
+	return err
+}

vendor/github.com/zillode/notify/util.go

@@ -0,0 +1,150 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+package notify
+
+import (
+	"errors"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+const all = ^Event(0)
+const sep = string(os.PathSeparator)
+
+var errDepth = errors.New("exceeded allowed iteration count (circular symlink?)")
+
+func min(i, j int) int {
+	if i > j {
+		return j
+	}
+	return i
+}
+
+func max(i, j int) int {
+	if i < j {
+		return j
+	}
+	return i
+}
+
+// must panics if err is non-nil.
+func must(err error) {
+	if err != nil {
+		panic(err)
+	}
+}
+
+// nonil gives first non-nil error from the given arguments.
+func nonil(err ...error) error {
+	for _, err := range err {
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func cleanpath(path string) (realpath string, isrec bool, err error) {
+	if strings.HasSuffix(path, "...") {
+		isrec = true
+		path = path[:len(path)-3]
+	}
+	if path, err = filepath.Abs(path); err != nil {
+		return "", false, err
+	}
+	if path, err = canonical(path); err != nil {
+		return "", false, err
+	}
+	return path, isrec, nil
+}
+
+// canonical resolves any symlink in the given path and returns it in a clean form.
+// It expects the path to be absolute. It fails to resolve circular symlinks by
+// maintaining a simple iteration limit.
+func canonical(p string) (string, error) {
+	p, err := filepath.Abs(p)
+	if err != nil {
+		return "", err
+	}
+	for i, j, depth := 1, 0, 1; i < len(p); i, depth = i+1, depth+1 {
+		if depth > 128 {
+			return "", &os.PathError{Op: "canonical", Path: p, Err: errDepth}
+		}
+		if j = strings.IndexRune(p[i:], '/'); j == -1 {
+			j, i = i, len(p)
+		} else {
+			j, i = i, i+j
+		}
+		fi, err := os.Lstat(p[:i])
+		if err != nil {
+			return "", err
+		}
+		if fi.Mode()&os.ModeSymlink == os.ModeSymlink {
+			s, err := os.Readlink(p[:i])
+			if err != nil {
+				return "", err
+			}
+			if filepath.IsAbs(s) {
+				p = "/" + s + p[i:]
+			} else {
+				p = p[:j] + s + p[i:]
+			}
+			i = 1 // no guarantee s is canonical, start all over
+		}
+	}
+	return filepath.Clean(p), nil
+}
+
+func joinevents(events []Event) (e Event) {
+	if len(events) == 0 {
+		e = All
+	} else {
+		for _, event := range events {
+			e |= event
+		}
+	}
+	return
+}
+
+func split(s string) (string, string) {
+	if i := lastIndexSep(s); i != -1 {
+		return s[:i], s[i+1:]
+	}
+	return "", s
+}
+
+func base(s string) string {
+	if i := lastIndexSep(s); i != -1 {
+		return s[i+1:]
+	}
+	return s
+}
+
+func indexbase(root, name string) int {
+	if n, m := len(root), len(name); m >= n && name[:n] == root &&
+		(n == m || name[n] == os.PathSeparator) {
+		return min(n+1, m)
+	}
+	return -1
+}
+
+func indexSep(s string) int {
+	for i := 0; i < len(s); i++ {
+		if s[i] == os.PathSeparator {
+			return i
+		}
+	}
+	return -1
+}
+
+func lastIndexSep(s string) int {
+	for i := len(s) - 1; i >= 0; i-- {
+		if s[i] == os.PathSeparator {
+			return i
+		}
+	}
+	return -1
+}

vendor/github.com/zillode/notify/watcher.go

@@ -0,0 +1,85 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+package notify
+
+import "errors"
+
+var (
+	errAlreadyWatched  = errors.New("path is already watched")
+	errNotWatched      = errors.New("path is not being watched")
+	errInvalidEventSet = errors.New("invalid event set provided")
+)
+
+// Watcher is a intermediate interface for wrapping inotify, ReadDirChangesW,
+// FSEvents, kqueue and poller implementations.
+//
+// The watcher implementation is expected to do its own mapping between paths and
+// create watchers if underlying event notification does not support it. For
+// the ease of implementation it is guaranteed that paths provided via Watch and
+// Unwatch methods are absolute and clean.
+type watcher interface {
+	// Watch requests a watcher creation for the given path and given event set.
+	Watch(path string, event Event) error
+
+	// Unwatch requests a watcher deletion for the given path and given event set.
+	Unwatch(path string) error
+
+	// Rewatch provides a functionality for modifying existing watch-points, like
+	// expanding its event set.
+	//
+	// Rewatch modifies existing watch-point under for the given path. It passes
+	// the existing event set currently registered for the given path, and the
+	// new, requested event set.
+	//
+	// It is guaranteed that Tree will not pass to Rewatch zero value for any
+	// of its arguments. If old == new and watcher can be upgraded to
+	// recursiveWatcher interface, a watch for the corresponding path is expected
+	// to be changed from recursive to the non-recursive one.
+	Rewatch(path string, old, new Event) error
+
+	// Close unwatches all paths that are registered. When Close returns, it
+	// is expected it will report no more events.
+	Close() error
+}
+
+// RecursiveWatcher is an interface for a Watcher for those OS, which do support
+// recursive watching over directories.
+type recursiveWatcher interface {
+	RecursiveWatch(path string, event Event) error
+
+	// RecursiveUnwatch removes a recursive watch-point given by the path. For
+	// native recursive implementation there is no difference in functionality
+	// between Unwatch and RecursiveUnwatch, however for those platforms, that
+	// requires emulation for recursive watch-points, the implementation differs.
+	RecursiveUnwatch(path string) error
+
+	// RecursiveRewatcher provides a functionality for modifying and/or relocating
+	// existing recursive watch-points.
+	//
+	// To relocate a watch-point means to unwatch oldpath and set a watch-point on
+	// newpath.
+	//
+	// To modify a watch-point means either to expand or shrink its event set.
+	//
+	// Tree can want to either relocate, modify or relocate and modify a watch-point
+	// via single RecursiveRewatch call.
+	//
+	// If oldpath == newpath, the watch-point is expected to change its event set value
+	// from oldevent to newevent.
+	//
+	// If oldevent == newevent, the watch-point is expected to relocate from oldpath
+	// to the newpath.
+	//
+	// If oldpath != newpath and oldevent != newevent, the watch-point is expected
+	// to relocate from oldpath to the newpath first and then change its event set
+	// value from oldevent to the newevent. In other words the end result must be
+	// a watch-point set on newpath with newevent value of its event set.
+	//
+	// It is guaranteed that Tree will not pass to RecurisveRewatcha zero value
+	// for any of its arguments. If oldpath == newpath and oldevent == newevent,
+	// a watch for the corresponding path is expected to be changed for
+	// non-recursive to the recursive one.
+	RecursiveRewatch(oldpath, newpath string, oldevent, newevent Event) error
+}

vendor/github.com/zillode/notify/watcher_fen.go

@@ -0,0 +1,161 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build solaris
+
+package notify
+
+import (
+	"fmt"
+	"os"
+	"syscall"
+)
+
+// newTrigger returns implementation of trigger.
+func newTrigger(pthLkp map[string]*watched) trigger {
+	return &fen{
+		pthLkp: pthLkp,
+		cf:     newCfen(),
+	}
+}
+
+// fen is a structure implementing trigger for FEN.
+type fen struct {
+	// p is a FEN port identifier
+	p int
+	// pthLkp is a structure mapping monitored files/dir with data about them,
+	// shared with parent trg structure
+	pthLkp map[string]*watched
+	// cf wraps C operations for FEN
+	cf cfen
+}
+
+// watched is a data structure representing watched file/directory.
+type watched struct {
+	trgWatched
+}
+
+// Stop implements trigger.
+func (f *fen) Stop() error {
+	return f.cf.portAlert(f.p)
+}
+
+// Close implements trigger.
+func (f *fen) Close() (err error) {
+	return syscall.Close(f.p)
+}
+
+// NewWatched implements trigger.
+func (*fen) NewWatched(p string, fi os.FileInfo) (*watched, error) {
+	return &watched{trgWatched{p: p, fi: fi}}, nil
+}
+
+// Record implements trigger.
+func (f *fen) Record(w *watched) {
+	f.pthLkp[w.p] = w
+}
+
+// Del implements trigger.
+func (f *fen) Del(w *watched) {
+	delete(f.pthLkp, w.p)
+}
+
+func inter2pe(n interface{}) PortEvent {
+	pe, ok := n.(PortEvent)
+	if !ok {
+		panic(fmt.Sprintf("fen: type should be PortEvent, %T instead", n))
+	}
+	return pe
+}
+
+// Watched implements trigger.
+func (f *fen) Watched(n interface{}) (*watched, int64, error) {
+	pe := inter2pe(n)
+	fo, ok := pe.PortevObject.(*FileObj)
+	if !ok || fo == nil {
+		panic(fmt.Sprintf("fen: type should be *FileObj, %T instead", fo))
+	}
+	w, ok := f.pthLkp[fo.Name]
+	if !ok {
+		return nil, 0, errNotWatched
+	}
+	return w, int64(pe.PortevEvents), nil
+}
+
+// init initializes FEN.
+func (f *fen) Init() (err error) {
+	f.p, err = f.cf.portCreate()
+	return
+}
+
+func fi2fo(fi os.FileInfo, p string) FileObj {
+	st, ok := fi.Sys().(*syscall.Stat_t)
+	if !ok {
+		panic(fmt.Sprintf("fen: type should be *syscall.Stat_t, %T instead", st))
+	}
+	return FileObj{Name: p, Atim: st.Atim, Mtim: st.Mtim, Ctim: st.Ctim}
+}
+
+// Unwatch implements trigger.
+func (f *fen) Unwatch(w *watched) error {
+	return f.cf.portDissociate(f.p, FileObj{Name: w.p})
+}
+
+// Watch implements trigger.
+func (f *fen) Watch(fi os.FileInfo, w *watched, e int64) error {
+	return f.cf.portAssociate(f.p, fi2fo(fi, w.p), int(e))
+}
+
+// Wait implements trigger.
+func (f *fen) Wait() (interface{}, error) {
+	var (
+		pe  PortEvent
+		err error
+	)
+	err = f.cf.portGet(f.p, &pe)
+	return pe, err
+}
+
+// IsStop implements trigger.
+func (f *fen) IsStop(n interface{}, err error) bool {
+	return err == syscall.EBADF || inter2pe(n).PortevSource == srcAlert
+}
+
+func init() {
+	encode = func(e Event, dir bool) (o int64) {
+		// Create event is not supported by FEN. Instead FileModified event will
+		// be registered. If this event will be reported on dir which is to be
+		// monitored for Create, dir will be rescanned and Create events will
+		// be generated and returned for new files. In case of files,
+		// if not requested FileModified event is reported, it will be ignored.
+		o = int64(e &^ Create)
+		if (e&Create != 0 && dir) || e&Write != 0 {
+			o = (o &^ int64(Write)) | int64(FileModified)
+		}
+		// Following events are 'exception events' and as such cannot be requested
+		// explicitly for monitoring or filtered out. If the will be reported
+		// by FEN and not subscribed with by user, they will be filtered out by
+		// watcher's logic.
+		o &= int64(^Rename & ^Remove &^ FileDelete &^ FileRenameTo &^
+			FileRenameFrom &^ Unmounted &^ MountedOver)
+		return
+	}
+	nat2not = map[Event]Event{
+		FileModified:   Write,
+		FileRenameFrom: Rename,
+		FileDelete:     Remove,
+		FileAccess:     Event(0),
+		FileAttrib:     Event(0),
+		FileRenameTo:   Event(0),
+		FileTrunc:      Event(0),
+		FileNoFollow:   Event(0),
+		Unmounted:      Event(0),
+		MountedOver:    Event(0),
+	}
+	not2nat = map[Event]Event{
+		Write:  FileModified,
+		Rename: FileRenameFrom,
+		Remove: FileDelete,
+	}
+}

vendor/github.com/zillode/notify/watcher_fen_cgo.go

@@ -0,0 +1,141 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build solaris
+
+package notify
+
+// #include <port.h>
+// #include <stdio.h>
+// #include <stdlib.h>
+// struct file_obj* newFo() { return (struct file_obj*) malloc(sizeof(struct file_obj)); }
+// port_event_t* newPe() { return (port_event_t*) malloc(sizeof(port_event_t)); }
+// uintptr_t conv(struct file_obj* fo) { return (uintptr_t) fo; }
+// struct file_obj* dconv(uintptr_t fo) { return (struct file_obj*) fo; }
+import "C"
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+const (
+	fileAccess     = Event(C.FILE_ACCESS)
+	fileModified   = Event(C.FILE_MODIFIED)
+	fileAttrib     = Event(C.FILE_ATTRIB)
+	fileDelete     = Event(C.FILE_DELETE)
+	fileRenameTo   = Event(C.FILE_RENAME_TO)
+	fileRenameFrom = Event(C.FILE_RENAME_FROM)
+	fileTrunc      = Event(C.FILE_TRUNC)
+	fileNoFollow   = Event(C.FILE_NOFOLLOW)
+	unmounted      = Event(C.UNMOUNTED)
+	mountedOver    = Event(C.MOUNTEDOVER)
+)
+
+// PortEvent is a notify's equivalent of port_event_t.
+type PortEvent struct {
+	PortevEvents int         // PortevEvents is an equivalent of portev_events.
+	PortevSource uint8       // PortevSource is an equivalent of portev_source.
+	PortevPad    uint8       // Portevpad is an equivalent of portev_pad.
+	PortevObject interface{} // PortevObject is an equivalent of portev_object.
+	PortevUser   uintptr     // PortevUser is an equivalent of portev_user.
+}
+
+// FileObj is a notify's equivalent of file_obj.
+type FileObj struct {
+	Atim syscall.Timespec // Atim is an equivalent of fo_atime.
+	Mtim syscall.Timespec // Mtim is an equivalent of fo_mtime.
+	Ctim syscall.Timespec // Ctim is an equivalent of fo_ctime.
+	Pad  [3]uintptr       // Pad is an equivalent of fo_pad.
+	Name string           // Name is an equivalent of fo_name.
+}
+
+type cfen struct {
+	p2pe map[string]*C.port_event_t
+	p2fo map[string]*C.struct_file_obj
+}
+
+func newCfen() cfen {
+	return cfen{
+		p2pe: make(map[string]*C.port_event_t),
+		p2fo: make(map[string]*C.struct_file_obj),
+	}
+}
+
+func unix2C(sec int64, nsec int64) (C.time_t, C.long) {
+	return C.time_t(sec), C.long(nsec)
+}
+
+func (c *cfen) portAssociate(p int, fo FileObj, e int) (err error) {
+	cfo := C.newFo()
+	cfo.fo_atime.tv_sec, cfo.fo_atime.tv_nsec = unix2C(fo.Atim.Unix())
+	cfo.fo_mtime.tv_sec, cfo.fo_mtime.tv_nsec = unix2C(fo.Mtim.Unix())
+	cfo.fo_ctime.tv_sec, cfo.fo_ctime.tv_nsec = unix2C(fo.Ctim.Unix())
+	cfo.fo_name = C.CString(fo.Name)
+	c.p2fo[fo.Name] = cfo
+	_, err = C.port_associate(C.int(p), srcFile, C.conv(cfo), C.int(e), nil)
+	return
+}
+
+func (c *cfen) portDissociate(port int, fo FileObj) (err error) {
+	cfo, ok := c.p2fo[fo.Name]
+	if !ok {
+		return errNotWatched
+	}
+	_, err = C.port_dissociate(C.int(port), srcFile, C.conv(cfo))
+	C.free(unsafe.Pointer(cfo.fo_name))
+	C.free(unsafe.Pointer(cfo))
+	delete(c.p2fo, fo.Name)
+	return
+}
+
+const srcAlert = C.PORT_SOURCE_ALERT
+const srcFile = C.PORT_SOURCE_FILE
+const alertSet = C.PORT_ALERT_SET
+
+func cfo2fo(cfo *C.struct_file_obj) *FileObj {
+	// Currently remaining attributes are not used.
+	if cfo == nil {
+		return nil
+	}
+	var fo FileObj
+	fo.Name = C.GoString(cfo.fo_name)
+	return &fo
+}
+
+func (c *cfen) portGet(port int, pe *PortEvent) (err error) {
+	cpe := C.newPe()
+	if _, err = C.port_get(C.int(port), cpe, nil); err != nil {
+		C.free(unsafe.Pointer(cpe))
+		return
+	}
+	pe.PortevEvents, pe.PortevSource, pe.PortevPad =
+		int(cpe.portev_events), uint8(cpe.portev_source), uint8(cpe.portev_pad)
+	pe.PortevObject = cfo2fo(C.dconv(cpe.portev_object))
+	pe.PortevUser = uintptr(cpe.portev_user)
+	C.free(unsafe.Pointer(cpe))
+	return
+}
+
+func (c *cfen) portCreate() (int, error) {
+	p, err := C.port_create()
+	return int(p), err
+}
+
+func (c *cfen) portAlert(p int) (err error) {
+	_, err = C.port_alert(C.int(p), alertSet, C.int(666), nil)
+	return
+}
+
+func (c *cfen) free() {
+	for i := range c.p2fo {
+		C.free(unsafe.Pointer(c.p2fo[i].fo_name))
+		C.free(unsafe.Pointer(c.p2fo[i]))
+	}
+	for i := range c.p2pe {
+		C.free(unsafe.Pointer(c.p2pe[i]))
+	}
+	c.p2fo = make(map[string]*C.struct_file_obj)
+	c.p2pe = make(map[string]*C.port_event_t)
+}

vendor/github.com/zillode/notify/watcher_fsevents.go

@@ -0,0 +1,311 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build darwin,!kqueue
+
+package notify
+
+import (
+	"errors"
+	"strings"
+	"sync/atomic"
+)
+
+const (
+	failure = uint32(FSEventsMustScanSubDirs | FSEventsUserDropped | FSEventsKernelDropped)
+	filter  = uint32(FSEventsCreated | FSEventsRemoved | FSEventsRenamed |
+		FSEventsModified | FSEventsInodeMetaMod)
+)
+
+// FSEvent represents single file event. It is created out of values passed by
+// FSEvents to FSEventStreamCallback function.
+type FSEvent struct {
+	Path  string // real path of the file or directory
+	ID    uint64 // ID of the event (FSEventStreamEventId)
+	Flags uint32 // joint FSEvents* flags (FSEventStreamEventFlags)
+}
+
+// splitflags separates event flags from single set into slice of flags.
+func splitflags(set uint32) (e []uint32) {
+	for i := uint32(1); set != 0; i, set = i<<1, set>>1 {
+		if (set & 1) != 0 {
+			e = append(e, i)
+		}
+	}
+	return
+}
+
+// watch represents a filesystem watchpoint. It is a higher level abstraction
+// over FSEvents' stream, which implements filtering of file events based
+// on path and event set. It emulates non-recursive watch-point by filtering out
+// events which paths are more than 1 level deeper than the watched path.
+type watch struct {
+	// prev stores last event set  per path in order to filter out old flags
+	// for new events, which appratenly FSEvents likes to retain. It's a disgusting
+	// hack, it should be researched how to get rid of it.
+	prev    map[string]uint32
+	c       chan<- EventInfo
+	stream  *stream
+	path    string
+	events  uint32
+	isrec   int32
+	flushed bool
+}
+
+// Example format:
+//
+//   ~ $ (trigger command) # (event set) -> (effective event set)
+//
+// Heuristics:
+//
+// 1. Create event is removed when it was present in previous event set.
+// Example:
+//
+//   ~ $ echo > file # Create|Write -> Create|Write
+//   ~ $ echo > file # Create|Write|InodeMetaMod -> Write|InodeMetaMod
+//
+// 2. Remove event is removed if it was present in previouse event set.
+// Example:
+//
+//   ~ $ touch file # Create -> Create
+//   ~ $ rm file    # Create|Remove -> Remove
+//   ~ $ touch file # Create|Remove -> Create
+//
+// 3. Write event is removed if not followed by InodeMetaMod on existing
+// file. Example:
+//
+//   ~ $ echo > file   # Create|Write -> Create|Write
+//   ~ $ chmod +x file # Create|Write|ChangeOwner -> ChangeOwner
+//
+// 4. Write&InodeMetaMod is removed when effective event set contain Remove event.
+// Example:
+//
+//   ~ $ echo > file # Write|InodeMetaMod -> Write|InodeMetaMod
+//   ~ $ rm file     # Remove|Write|InodeMetaMod -> Remove
+//
+func (w *watch) strip(base string, set uint32) uint32 {
+	const (
+		write = FSEventsModified | FSEventsInodeMetaMod
+		both  = FSEventsCreated | FSEventsRemoved
+	)
+	switch w.prev[base] {
+	case FSEventsCreated:
+		set &^= FSEventsCreated
+		if set&FSEventsRemoved != 0 {
+			w.prev[base] = FSEventsRemoved
+			set &^= write
+		}
+	case FSEventsRemoved:
+		set &^= FSEventsRemoved
+		if set&FSEventsCreated != 0 {
+			w.prev[base] = FSEventsCreated
+		}
+	default:
+		switch set & both {
+		case FSEventsCreated:
+			w.prev[base] = FSEventsCreated
+		case FSEventsRemoved:
+			w.prev[base] = FSEventsRemoved
+			set &^= write
+		}
+	}
+	dbgprintf("split()=%v\n", Event(set))
+	return set
+}
+
+// Dispatch is a stream function which forwards given file events for the watched
+// path to underlying FileInfo channel.
+func (w *watch) Dispatch(ev []FSEvent) {
+	events := atomic.LoadUint32(&w.events)
+	isrec := (atomic.LoadInt32(&w.isrec) == 1)
+	for i := range ev {
+		if ev[i].Flags&FSEventsHistoryDone != 0 {
+			w.flushed = true
+			continue
+		}
+		if !w.flushed {
+			continue
+		}
+		dbgprintf("%v (0x%x) (%s, i=%d, ID=%d, len=%d)\n", Event(ev[i].Flags),
+			ev[i].Flags, ev[i].Path, i, ev[i].ID, len(ev))
+		if ev[i].Flags&failure != 0 {
+			// TODO(rjeczalik): missing error handling
+			continue
+		}
+		if !strings.HasPrefix(ev[i].Path, w.path) {
+			continue
+		}
+		n := len(w.path)
+		base := ""
+		if len(ev[i].Path) > n {
+			if ev[i].Path[n] != '/' {
+				continue
+			}
+			base = ev[i].Path[n+1:]
+			if !isrec && strings.IndexByte(base, '/') != -1 {
+				continue
+			}
+		}
+		// TODO(rjeczalik): get diff only from filtered events?
+		e := w.strip(string(base), ev[i].Flags) & events
+		if e == 0 {
+			continue
+		}
+		for _, e := range splitflags(e) {
+			dbgprintf("%d: single event: %v", ev[i].ID, Event(e))
+			w.c <- &event{
+				fse:   ev[i],
+				event: Event(e),
+			}
+		}
+	}
+}
+
+// Stop closes underlying FSEvents stream and stops dispatching events.
+func (w *watch) Stop() {
+	w.stream.Stop()
+	// TODO(rjeczalik): make (*stream).Stop flush synchronously undelivered events,
+	// so the following hack can be removed. It should flush all the streams
+	// concurrently as we care not to block too much here.
+	atomic.StoreUint32(&w.events, 0)
+	atomic.StoreInt32(&w.isrec, 0)
+}
+
+// fsevents implements Watcher and RecursiveWatcher interfaces backed by FSEvents
+// framework.
+type fsevents struct {
+	watches map[string]*watch
+	c       chan<- EventInfo
+}
+
+func newWatcher(c chan<- EventInfo) watcher {
+	return &fsevents{
+		watches: make(map[string]*watch),
+		c:       c,
+	}
+}
+
+func (fse *fsevents) watch(path string, event Event, isrec int32) (err error) {
+	if _, ok := fse.watches[path]; ok {
+		return errAlreadyWatched
+	}
+	w := &watch{
+		prev:   make(map[string]uint32),
+		c:      fse.c,
+		path:   path,
+		events: uint32(event),
+		isrec:  isrec,
+	}
+	w.stream = newStream(path, w.Dispatch)
+	if err = w.stream.Start(); err != nil {
+		return err
+	}
+	fse.watches[path] = w
+	return nil
+}
+
+func (fse *fsevents) unwatch(path string) (err error) {
+	w, ok := fse.watches[path]
+	if !ok {
+		return errNotWatched
+	}
+	w.stream.Stop()
+	delete(fse.watches, path)
+	return nil
+}
+
+// Watch implements Watcher interface. It fails with non-nil error when setting
+// the watch-point by FSEvents fails or with errAlreadyWatched error when
+// the given path is already watched.
+func (fse *fsevents) Watch(path string, event Event) error {
+	return fse.watch(path, event, 0)
+}
+
+// Unwatch implements Watcher interface. It fails with errNotWatched when
+// the given path is not being watched.
+func (fse *fsevents) Unwatch(path string) error {
+	return fse.unwatch(path)
+}
+
+// Rewatch implements Watcher interface. It fails with errNotWatched when
+// the given path is not being watched or with errInvalidEventSet when oldevent
+// does not match event set the watch-point currently holds.
+func (fse *fsevents) Rewatch(path string, oldevent, newevent Event) error {
+	w, ok := fse.watches[path]
+	if !ok {
+		return errNotWatched
+	}
+	if !atomic.CompareAndSwapUint32(&w.events, uint32(oldevent), uint32(newevent)) {
+		return errInvalidEventSet
+	}
+	atomic.StoreInt32(&w.isrec, 0)
+	return nil
+}
+
+// RecursiveWatch implements RecursiveWatcher interface. It fails with non-nil
+// error when setting the watch-point by FSEvents fails or with errAlreadyWatched
+// error when the given path is already watched.
+func (fse *fsevents) RecursiveWatch(path string, event Event) error {
+	return fse.watch(path, event, 1)
+}
+
+// RecursiveUnwatch implements RecursiveWatcher interface. It fails with
+// errNotWatched when the given path is not being watched.
+//
+// TODO(rjeczalik): fail if w.isrec == 0?
+func (fse *fsevents) RecursiveUnwatch(path string) error {
+	return fse.unwatch(path)
+}
+
+// RecrusiveRewatch implements RecursiveWatcher interface. It fails:
+//
+//   * with errNotWatched when the given path is not being watched
+//   * with errInvalidEventSet when oldevent does not match the current event set
+//   * with errAlreadyWatched when watch-point given by the oldpath was meant to
+//     be relocated to newpath, but the newpath is already watched
+//   * a non-nil error when setting the watch-point with FSEvents fails
+//
+// TODO(rjeczalik): Improve handling of watch-point relocation? See two TODOs
+// that follows.
+func (fse *fsevents) RecursiveRewatch(oldpath, newpath string, oldevent, newevent Event) error {
+	switch [2]bool{oldpath == newpath, oldevent == newevent} {
+	case [2]bool{true, true}:
+		w, ok := fse.watches[oldpath]
+		if !ok {
+			return errNotWatched
+		}
+		atomic.StoreInt32(&w.isrec, 1)
+		return nil
+	case [2]bool{true, false}:
+		w, ok := fse.watches[oldpath]
+		if !ok {
+			return errNotWatched
+		}
+		if !atomic.CompareAndSwapUint32(&w.events, uint32(oldevent), uint32(newevent)) {
+			return errors.New("invalid event state diff")
+		}
+		atomic.StoreInt32(&w.isrec, 1)
+		return nil
+	default:
+		// TODO(rjeczalik): rewatch newpath only if exists?
+		// TODO(rjeczalik): migrate w.prev to new watch?
+		if _, ok := fse.watches[newpath]; ok {
+			return errAlreadyWatched
+		}
+		if err := fse.Unwatch(oldpath); err != nil {
+			return err
+		}
+		// TODO(rjeczalik): revert unwatch if watch fails?
+		return fse.watch(newpath, newevent, 1)
+	}
+}
+
+// Close unwatches all watch-points.
+func (fse *fsevents) Close() error {
+	for _, w := range fse.watches {
+		w.Stop()
+	}
+	fse.watches = nil
+	return nil
+}

vendor/github.com/zillode/notify/watcher_fsevents_cgo.go

@@ -0,0 +1,190 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build darwin,!kqueue
+
+package notify
+
+/*
+#include <CoreServices/CoreServices.h>
+
+typedef void (*CFRunLoopPerformCallBack)(void*);
+
+void gosource(void *);
+void gostream(uintptr_t, uintptr_t, size_t, uintptr_t, uintptr_t, uintptr_t);
+
+static FSEventStreamRef EventStreamCreate(FSEventStreamContext * context, uintptr_t info, CFArrayRef paths, FSEventStreamEventId since, CFTimeInterval latency, FSEventStreamCreateFlags flags) {
+	context->info = (void*) info;
+	return FSEventStreamCreate(NULL, (FSEventStreamCallback) gostream, context, paths, since, latency, flags);
+}
+
+#cgo LDFLAGS: -framework CoreServices
+*/
+import "C"
+
+import (
+	"errors"
+	"os"
+	"sync"
+	"sync/atomic"
+	"time"
+	"unsafe"
+)
+
+var nilstream C.FSEventStreamRef
+
+// Default arguments for FSEventStreamCreate function.
+var (
+	latency C.CFTimeInterval
+	flags   = C.FSEventStreamCreateFlags(C.kFSEventStreamCreateFlagFileEvents | C.kFSEventStreamCreateFlagNoDefer)
+	since   = uint64(C.FSEventsGetCurrentEventId())
+)
+
+var runloop C.CFRunLoopRef // global runloop which all streams are registered with
+var wg sync.WaitGroup      // used to wait until the runloop starts
+
+// source is used for synchronization purposes - it signals when runloop has
+// started and is ready via the wg. It also serves purpose of a dummy source,
+// thanks to it the runloop does not return as it also has at least one source
+// registered.
+var source = C.CFRunLoopSourceCreate(nil, 0, &C.CFRunLoopSourceContext{
+	perform: (C.CFRunLoopPerformCallBack)(C.gosource),
+})
+
+// Errors returned when FSEvents functions fail.
+var (
+	errCreate = os.NewSyscallError("FSEventStreamCreate", errors.New("NULL"))
+	errStart  = os.NewSyscallError("FSEventStreamStart", errors.New("false"))
+)
+
+// initializes the global runloop and ensures any created stream awaits its
+// readiness.
+func init() {
+	wg.Add(1)
+	go func() {
+		runloop = C.CFRunLoopGetCurrent()
+		C.CFRunLoopAddSource(runloop, source, C.kCFRunLoopDefaultMode)
+		C.CFRunLoopRun()
+		panic("runloop has just unexpectedly stopped")
+	}()
+	C.CFRunLoopSourceSignal(source)
+}
+
+//export gosource
+func gosource(unsafe.Pointer) {
+	time.Sleep(time.Second)
+	wg.Done()
+}
+
+//export gostream
+func gostream(_, info uintptr, n C.size_t, paths, flags, ids uintptr) {
+	const (
+		offchar = unsafe.Sizeof((*C.char)(nil))
+		offflag = unsafe.Sizeof(C.FSEventStreamEventFlags(0))
+		offid   = unsafe.Sizeof(C.FSEventStreamEventId(0))
+	)
+	if n == 0 {
+		return
+	}
+	ev := make([]FSEvent, 0, int(n))
+	for i := uintptr(0); i < uintptr(n); i++ {
+		switch flags := *(*uint32)(unsafe.Pointer((flags + i*offflag))); {
+		case flags&uint32(FSEventsEventIdsWrapped) != 0:
+			atomic.StoreUint64(&since, uint64(C.FSEventsGetCurrentEventId()))
+		default:
+			ev = append(ev, FSEvent{
+				Path:  C.GoString(*(**C.char)(unsafe.Pointer(paths + i*offchar))),
+				Flags: flags,
+				ID:    *(*uint64)(unsafe.Pointer(ids + i*offid)),
+			})
+		}
+
+	}
+	streamFuncs.get(info)(ev)
+}
+
+// StreamFunc is a callback called when stream receives file events.
+type streamFunc func([]FSEvent)
+
+var streamFuncs = streamFuncRegistry{m: map[uintptr]streamFunc{}}
+
+type streamFuncRegistry struct {
+	mu sync.Mutex
+	m  map[uintptr]streamFunc
+	i  uintptr
+}
+
+func (r *streamFuncRegistry) get(id uintptr) streamFunc {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	return r.m[id]
+}
+
+func (r *streamFuncRegistry) add(fn streamFunc) uintptr {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	r.i++
+	r.m[r.i] = fn
+	return r.i
+}
+
+func (r *streamFuncRegistry) delete(id uintptr) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	delete(r.m, id)
+}
+
+// Stream represents single watch-point which listens for events scheduled by
+// the global runloop.
+type stream struct {
+	path string
+	ref  C.FSEventStreamRef
+	info uintptr
+}
+
+// NewStream creates a stream for given path, listening for file events and
+// calling fn upon receiving any.
+func newStream(path string, fn streamFunc) *stream {
+	return &stream{
+		path: path,
+		info: streamFuncs.add(fn),
+	}
+}
+
+// Start creates a FSEventStream for the given path and schedules it with
+// global runloop. It's a nop if the stream was already started.
+func (s *stream) Start() error {
+	if s.ref != nilstream {
+		return nil
+	}
+	wg.Wait()
+	p := C.CFStringCreateWithCStringNoCopy(nil, C.CString(s.path), C.kCFStringEncodingUTF8, nil)
+	path := C.CFArrayCreate(nil, (*unsafe.Pointer)(unsafe.Pointer(&p)), 1, nil)
+	ctx := C.FSEventStreamContext{}
+	ref := C.EventStreamCreate(&ctx, C.uintptr_t(s.info), path, C.FSEventStreamEventId(atomic.LoadUint64(&since)), latency, flags)
+	if ref == nilstream {
+		return errCreate
+	}
+	C.FSEventStreamScheduleWithRunLoop(ref, runloop, C.kCFRunLoopDefaultMode)
+	if C.FSEventStreamStart(ref) == C.Boolean(0) {
+		C.FSEventStreamInvalidate(ref)
+		return errStart
+	}
+	C.CFRunLoopWakeUp(runloop)
+	s.ref = ref
+	return nil
+}
+
+// Stop stops underlying FSEventStream and unregisters it from global runloop.
+func (s *stream) Stop() {
+	if s.ref == nilstream {
+		return
+	}
+	wg.Wait()
+	C.FSEventStreamStop(s.ref)
+	C.FSEventStreamInvalidate(s.ref)
+	C.CFRunLoopWakeUp(runloop)
+	s.ref = nilstream
+	streamFuncs.delete(s.info)
+}

vendor/github.com/zillode/notify/watcher_inotify.go

@@ -0,0 +1,405 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build linux
+
+package notify
+
+import (
+	"bytes"
+	"errors"
+	"path/filepath"
+	"runtime"
+	"sync"
+	"sync/atomic"
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+)
+
+// eventBufferSize defines the size of the buffer given to read(2) function. One
+// should not depend on this value, since it was arbitrary chosen and may be
+// changed in the future.
+const eventBufferSize = 64 * (unix.SizeofInotifyEvent + unix.PathMax + 1)
+
+// consumersCount defines the number of consumers in producer-consumer based
+// implementation. Each consumer is run in a separate goroutine and has read
+// access to watched files map.
+const consumersCount = 2
+
+const invalidDescriptor = -1
+
+// watched is a pair of file path and inotify mask used as a value in
+// watched files map.
+type watched struct {
+	path string
+	mask uint32
+}
+
+// inotify implements Watcher interface.
+type inotify struct {
+	sync.RWMutex                       // protects inotify.m map
+	m            map[int32]*watched    // watch descriptor to watched object
+	fd           int32                 // inotify file descriptor
+	pipefd       []int                 // pipe's read and write descriptors
+	epfd         int                   // epoll descriptor
+	epes         []unix.EpollEvent     // epoll events
+	buffer       [eventBufferSize]byte // inotify event buffer
+	wg           sync.WaitGroup        // wait group used to close main loop
+	c            chan<- EventInfo      // event dispatcher channel
+}
+
+// NewWatcher creates new non-recursive inotify backed by inotify.
+func newWatcher(c chan<- EventInfo) watcher {
+	i := &inotify{
+		m:      make(map[int32]*watched),
+		fd:     invalidDescriptor,
+		pipefd: []int{invalidDescriptor, invalidDescriptor},
+		epfd:   invalidDescriptor,
+		epes:   make([]unix.EpollEvent, 0),
+		c:      c,
+	}
+	runtime.SetFinalizer(i, func(i *inotify) {
+		i.epollclose()
+		if i.fd != invalidDescriptor {
+			unix.Close(int(i.fd))
+		}
+	})
+	return i
+}
+
+// Watch implements notify.watcher interface.
+func (i *inotify) Watch(path string, e Event) error {
+	return i.watch(path, e)
+}
+
+// Rewatch implements notify.watcher interface.
+func (i *inotify) Rewatch(path string, _, newevent Event) error {
+	return i.watch(path, newevent)
+}
+
+// watch adds a new watcher to the set of watched objects or modifies the existing
+// one. If called for the first time, this function initializes inotify filesystem
+// monitor and starts producer-consumers goroutines.
+func (i *inotify) watch(path string, e Event) (err error) {
+	if e&^(All|Event(unix.IN_ALL_EVENTS)) != 0 {
+		return errors.New("notify: unknown event")
+	}
+	if err = i.lazyinit(); err != nil {
+		return
+	}
+	iwd, err := unix.InotifyAddWatch(int(i.fd), path, encode(e))
+	if err != nil {
+		return
+	}
+	i.RLock()
+	wd := i.m[int32(iwd)]
+	i.RUnlock()
+	if wd == nil {
+		i.Lock()
+		if i.m[int32(iwd)] == nil {
+			i.m[int32(iwd)] = &watched{path: path, mask: uint32(e)}
+		}
+		i.Unlock()
+	} else {
+		i.Lock()
+		wd.mask = uint32(e)
+		i.Unlock()
+	}
+	return nil
+}
+
+// lazyinit sets up all required file descriptors and starts 1+consumersCount
+// goroutines. The producer goroutine blocks until file-system notifications
+// occur. Then, all events are read from system buffer and sent to consumer
+// goroutines which construct valid notify events. This method uses
+// Double-Checked Locking optimization.
+func (i *inotify) lazyinit() error {
+	if atomic.LoadInt32(&i.fd) == invalidDescriptor {
+		i.Lock()
+		defer i.Unlock()
+		if atomic.LoadInt32(&i.fd) == invalidDescriptor {
+			fd, err := unix.InotifyInit1(unix.IN_CLOEXEC)
+			if err != nil {
+				return err
+			}
+			i.fd = int32(fd)
+			if err = i.epollinit(); err != nil {
+				_, _ = i.epollclose(), unix.Close(int(fd)) // Ignore errors.
+				i.fd = invalidDescriptor
+				return err
+			}
+			esch := make(chan []*event)
+			go i.loop(esch)
+			i.wg.Add(consumersCount)
+			for n := 0; n < consumersCount; n++ {
+				go i.send(esch)
+			}
+		}
+	}
+	return nil
+}
+
+// epollinit opens an epoll file descriptor and creates a pipe which will be
+// used to wake up the epoll_wait(2) function. Then, file descriptor associated
+// with inotify event queue and the read end of the pipe are added to epoll set.
+// Note that `fd` member must be set before this function is called.
+func (i *inotify) epollinit() (err error) {
+	if i.epfd, err = unix.EpollCreate1(0); err != nil {
+		return
+	}
+	if err = unix.Pipe(i.pipefd); err != nil {
+		return
+	}
+	i.epes = []unix.EpollEvent{
+		{Events: unix.EPOLLIN, Fd: i.fd},
+		{Events: unix.EPOLLIN, Fd: int32(i.pipefd[0])},
+	}
+	if err = unix.EpollCtl(i.epfd, unix.EPOLL_CTL_ADD, int(i.fd), &i.epes[0]); err != nil {
+		return
+	}
+	return unix.EpollCtl(i.epfd, unix.EPOLL_CTL_ADD, i.pipefd[0], &i.epes[1])
+}
+
+// epollclose closes the file descriptor created by the call to epoll_create(2)
+// and two file descriptors opened by pipe(2) function.
+func (i *inotify) epollclose() (err error) {
+	if i.epfd != invalidDescriptor {
+		if err = unix.Close(i.epfd); err == nil {
+			i.epfd = invalidDescriptor
+		}
+	}
+	for n, fd := range i.pipefd {
+		if fd != invalidDescriptor {
+			switch e := unix.Close(fd); {
+			case e != nil && err == nil:
+				err = e
+			case e == nil:
+				i.pipefd[n] = invalidDescriptor
+			}
+		}
+	}
+	return
+}
+
+// loop blocks until either inotify or pipe file descriptor is ready for I/O.
+// All read operations triggered by filesystem notifications are forwarded to
+// one of the event's consumers. If pipe fd became ready, loop function closes
+// all file descriptors opened by lazyinit method and returns afterwards.
+func (i *inotify) loop(esch chan<- []*event) {
+	epes := make([]unix.EpollEvent, 1)
+	fd := atomic.LoadInt32(&i.fd)
+	for {
+		switch _, err := unix.EpollWait(i.epfd, epes, -1); err {
+		case nil:
+			switch epes[0].Fd {
+			case fd:
+				esch <- i.read()
+				epes[0].Fd = 0
+			case int32(i.pipefd[0]):
+				i.Lock()
+				defer i.Unlock()
+				if err = unix.Close(int(fd)); err != nil && err != unix.EINTR {
+					panic("notify: close(2) error " + err.Error())
+				}
+				atomic.StoreInt32(&i.fd, invalidDescriptor)
+				if err = i.epollclose(); err != nil && err != unix.EINTR {
+					panic("notify: epollclose error " + err.Error())
+				}
+				close(esch)
+				return
+			}
+		case unix.EINTR:
+			continue
+		default: // We should never reach this line.
+			panic("notify: epoll_wait(2) error " + err.Error())
+		}
+	}
+}
+
+// read reads events from an inotify file descriptor. It does not handle errors
+// returned from read(2) function since they are not critical to watcher logic.
+func (i *inotify) read() (es []*event) {
+	n, err := unix.Read(int(i.fd), i.buffer[:])
+	if err != nil || n < unix.SizeofInotifyEvent {
+		return
+	}
+	var sys *unix.InotifyEvent
+	nmin := n - unix.SizeofInotifyEvent
+	for pos, path := 0, ""; pos <= nmin; {
+		sys = (*unix.InotifyEvent)(unsafe.Pointer(&i.buffer[pos]))
+		pos += unix.SizeofInotifyEvent
+		if path = ""; sys.Len > 0 {
+			endpos := pos + int(sys.Len)
+			path = string(bytes.TrimRight(i.buffer[pos:endpos], "\x00"))
+			pos = endpos
+		}
+		es = append(es, &event{
+			sys: unix.InotifyEvent{
+				Wd:     sys.Wd,
+				Mask:   sys.Mask,
+				Cookie: sys.Cookie,
+			},
+			path: path,
+		})
+	}
+	return
+}
+
+// send is a consumer function which sends events to event dispatcher channel.
+// It is run in a separate goroutine in order to not block loop method when
+// possibly expensive write operations are performed on inotify map.
+func (i *inotify) send(esch <-chan []*event) {
+	for es := range esch {
+		for _, e := range i.transform(es) {
+			if e != nil {
+				i.c <- e
+			}
+		}
+	}
+	i.wg.Done()
+}
+
+// transform prepares events read from inotify file descriptor for sending to
+// user. It removes invalid events and these which are no longer present in
+// inotify map. This method may also split one raw event into two different ones
+// when system-dependent result is required.
+func (i *inotify) transform(es []*event) []*event {
+	var multi []*event
+	i.RLock()
+	for idx, e := range es {
+		if e.sys.Mask&(unix.IN_IGNORED|unix.IN_Q_OVERFLOW) != 0 {
+			es[idx] = nil
+			continue
+		}
+		wd, ok := i.m[e.sys.Wd]
+		if !ok || e.sys.Mask&encode(Event(wd.mask)) == 0 {
+			es[idx] = nil
+			continue
+		}
+		if e.path == "" {
+			e.path = wd.path
+		} else {
+			e.path = filepath.Join(wd.path, e.path)
+		}
+		multi = append(multi, decode(Event(wd.mask), e))
+		if e.event == 0 {
+			es[idx] = nil
+		}
+	}
+	i.RUnlock()
+	es = append(es, multi...)
+	return es
+}
+
+// encode converts notify system-independent events to valid inotify mask
+// which can be passed to inotify_add_watch(2) function.
+func encode(e Event) uint32 {
+	if e&Create != 0 {
+		e = (e ^ Create) | InCreate | InMovedTo
+	}
+	if e&Remove != 0 {
+		e = (e ^ Remove) | InDelete | InDeleteSelf
+	}
+	if e&Write != 0 {
+		e = (e ^ Write) | InModify
+	}
+	if e&Rename != 0 {
+		e = (e ^ Rename) | InMovedFrom | InMoveSelf
+	}
+	return uint32(e)
+}
+
+// decode uses internally stored mask to distinguish whether system-independent
+// or system-dependent event is requested. The first one is created by modifying
+// `e` argument. decode method sets e.event value to 0 when an event should be
+// skipped. System-dependent event is set as the function's return value which
+// can be nil when the event should not be passed on.
+func decode(mask Event, e *event) (syse *event) {
+	if sysmask := uint32(mask) & e.sys.Mask; sysmask != 0 {
+		syse = &event{sys: unix.InotifyEvent{
+			Wd:     e.sys.Wd,
+			Mask:   e.sys.Mask,
+			Cookie: e.sys.Cookie,
+		}, event: Event(sysmask), path: e.path}
+	}
+	imask := encode(mask)
+	switch {
+	case mask&Create != 0 && imask&uint32(InCreate|InMovedTo)&e.sys.Mask != 0:
+		e.event = Create
+	case mask&Remove != 0 && imask&uint32(InDelete|InDeleteSelf)&e.sys.Mask != 0:
+		e.event = Remove
+	case mask&Write != 0 && imask&uint32(InModify)&e.sys.Mask != 0:
+		e.event = Write
+	case mask&Rename != 0 && imask&uint32(InMovedFrom|InMoveSelf)&e.sys.Mask != 0:
+		e.event = Rename
+	default:
+		e.event = 0
+	}
+	return
+}
+
+// Unwatch implements notify.watcher interface. It looks for watch descriptor
+// related to registered path and if found, calls inotify_rm_watch(2) function.
+// This method is allowed to return EINVAL error when concurrently requested to
+// delete identical path.
+func (i *inotify) Unwatch(path string) (err error) {
+	iwd := int32(invalidDescriptor)
+	i.RLock()
+	for iwdkey, wd := range i.m {
+		if wd.path == path {
+			iwd = iwdkey
+			break
+		}
+	}
+	i.RUnlock()
+	if iwd == invalidDescriptor {
+		return errors.New("notify: path " + path + " is already watched")
+	}
+	fd := atomic.LoadInt32(&i.fd)
+	if err = removeInotifyWatch(fd, iwd); err != nil {
+		return
+	}
+	i.Lock()
+	delete(i.m, iwd)
+	i.Unlock()
+	return nil
+}
+
+// Close implements notify.watcher interface. It removes all existing watch
+// descriptors and wakes up producer goroutine by sending data to the write end
+// of the pipe. The function waits for a signal from producer which means that
+// all operations on current monitoring instance are done.
+func (i *inotify) Close() (err error) {
+	i.Lock()
+	if fd := atomic.LoadInt32(&i.fd); fd == invalidDescriptor {
+		i.Unlock()
+		return nil
+	}
+	for iwd := range i.m {
+		if e := removeInotifyWatch(i.fd, iwd); e != nil && err == nil {
+			err = e
+		}
+		delete(i.m, iwd)
+	}
+	switch _, errwrite := unix.Write(i.pipefd[1], []byte{0x00}); {
+	case errwrite != nil && err == nil:
+		err = errwrite
+		fallthrough
+	case errwrite != nil:
+		i.Unlock()
+	default:
+		i.Unlock()
+		i.wg.Wait()
+	}
+	return
+}
+
+// if path was removed, notify already removed the watch and returns EINVAL error
+func removeInotifyWatch(fd int32, iwd int32) (err error) {
+	if _, err = unix.InotifyRmWatch(int(fd), uint32(iwd)); err != nil && err != unix.EINVAL {
+		return
+	}
+	return nil
+}

vendor/github.com/zillode/notify/watcher_kqueue.go

@@ -0,0 +1,189 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build darwin,kqueue dragonfly freebsd netbsd openbsd
+
+package notify
+
+import (
+	"fmt"
+	"os"
+	"syscall"
+)
+
+// newTrigger returns implementation of trigger.
+func newTrigger(pthLkp map[string]*watched) trigger {
+	return &kq{
+		pthLkp: pthLkp,
+		idLkp:  make(map[int]*watched),
+	}
+}
+
+// kq is a structure implementing trigger for kqueue.
+type kq struct {
+	// fd is a kqueue file descriptor
+	fd int
+	// pipefds are file descriptors used to stop `Kevent` call.
+	pipefds [2]int
+	// idLkp is a data structure mapping file descriptors with data about watching
+	// represented by them files/directories.
+	idLkp map[int]*watched
+	// pthLkp is a structure mapping monitored files/dir with data about them,
+	// shared with parent trg structure
+	pthLkp map[string]*watched
+}
+
+// watched is a data structure representing watched file/directory.
+type watched struct {
+	trgWatched
+	// fd is a file descriptor for watched file/directory.
+	fd int
+}
+
+// Stop implements trigger.
+func (k *kq) Stop() (err error) {
+	// trigger event used to interrupt Kevent call.
+	_, err = syscall.Write(k.pipefds[1], []byte{0x00})
+	return
+}
+
+// Close implements trigger.
+func (k *kq) Close() error {
+	return syscall.Close(k.fd)
+}
+
+// NewWatched implements trigger.
+func (*kq) NewWatched(p string, fi os.FileInfo) (*watched, error) {
+	fd, err := syscall.Open(p, syscall.O_NONBLOCK|syscall.O_RDONLY, 0)
+	if err != nil {
+		return nil, err
+	}
+	return &watched{
+		trgWatched: trgWatched{p: p, fi: fi},
+		fd:         fd,
+	}, nil
+}
+
+// Record implements trigger.
+func (k *kq) Record(w *watched) {
+	k.idLkp[w.fd], k.pthLkp[w.p] = w, w
+}
+
+// Del implements trigger.
+func (k *kq) Del(w *watched) {
+	syscall.Close(w.fd)
+	delete(k.idLkp, w.fd)
+	delete(k.pthLkp, w.p)
+}
+
+func inter2kq(n interface{}) syscall.Kevent_t {
+	kq, ok := n.(syscall.Kevent_t)
+	if !ok {
+		panic(fmt.Sprintf("kqueue: type should be Kevent_t, %T instead", n))
+	}
+	return kq
+}
+
+// Init implements trigger.
+func (k *kq) Init() (err error) {
+	if k.fd, err = syscall.Kqueue(); err != nil {
+		return
+	}
+	// Creates pipe used to stop `Kevent` call by registering it,
+	// watching read end and writing to other end of it.
+	if err = syscall.Pipe(k.pipefds[:]); err != nil {
+		return nonil(err, k.Close())
+	}
+	var kevn [1]syscall.Kevent_t
+	syscall.SetKevent(&kevn[0], k.pipefds[0], syscall.EVFILT_READ, syscall.EV_ADD)
+	if _, err = syscall.Kevent(k.fd, kevn[:], nil, nil); err != nil {
+		return nonil(err, k.Close())
+	}
+	return
+}
+
+// Unwatch implements trigger.
+func (k *kq) Unwatch(w *watched) (err error) {
+	var kevn [1]syscall.Kevent_t
+	syscall.SetKevent(&kevn[0], w.fd, syscall.EVFILT_VNODE, syscall.EV_DELETE)
+
+	_, err = syscall.Kevent(k.fd, kevn[:], nil, nil)
+	return
+}
+
+// Watch implements trigger.
+func (k *kq) Watch(fi os.FileInfo, w *watched, e int64) (err error) {
+	var kevn [1]syscall.Kevent_t
+	syscall.SetKevent(&kevn[0], w.fd, syscall.EVFILT_VNODE,
+		syscall.EV_ADD|syscall.EV_CLEAR)
+	kevn[0].Fflags = uint32(e)
+
+	_, err = syscall.Kevent(k.fd, kevn[:], nil, nil)
+	return
+}
+
+// Wait implements trigger.
+func (k *kq) Wait() (interface{}, error) {
+	var (
+		kevn [1]syscall.Kevent_t
+		err  error
+	)
+	kevn[0] = syscall.Kevent_t{}
+	_, err = syscall.Kevent(k.fd, nil, kevn[:], nil)
+
+	return kevn[0], err
+}
+
+// Watched implements trigger.
+func (k *kq) Watched(n interface{}) (*watched, int64, error) {
+	kevn, ok := n.(syscall.Kevent_t)
+	if !ok {
+		panic(fmt.Sprintf("kq: type should be syscall.Kevent_t, %T instead", kevn))
+	}
+	if _, ok = k.idLkp[int(kevn.Ident)]; !ok {
+		return nil, 0, errNotWatched
+	}
+	return k.idLkp[int(kevn.Ident)], int64(kevn.Fflags), nil
+}
+
+// IsStop implements trigger.
+func (k *kq) IsStop(n interface{}, err error) bool {
+	return int(inter2kq(n).Ident) == k.pipefds[0]
+}
+
+func init() {
+	encode = func(e Event, dir bool) (o int64) {
+		// Create event is not supported by kqueue. Instead NoteWrite event will
+		// be registered for a directory. If this event will be reported on dir
+		// which is to be monitored for Create, dir will be rescanned
+		// and Create events will be generated and returned for new files.
+		// In case of files, if not requested NoteRename event is reported,
+		// it will be ignored.
+		o = int64(e &^ Create)
+		if (e&Create != 0 && dir) || e&Write != 0 {
+			o = (o &^ int64(Write)) | int64(NoteWrite)
+		}
+		if e&Rename != 0 {
+			o = (o &^ int64(Rename)) | int64(NoteRename)
+		}
+		if e&Remove != 0 {
+			o = (o &^ int64(Remove)) | int64(NoteDelete)
+		}
+		return
+	}
+	nat2not = map[Event]Event{
+		NoteWrite:  Write,
+		NoteRename: Rename,
+		NoteDelete: Remove,
+		NoteExtend: Event(0),
+		NoteAttrib: Event(0),
+		NoteRevoke: Event(0),
+		NoteLink:   Event(0),
+	}
+	not2nat = map[Event]Event{
+		Write:  NoteWrite,
+		Rename: NoteRename,
+		Remove: NoteDelete,
+	}
+}

vendor/github.com/zillode/notify/watcher_readdcw.go

@@ -0,0 +1,582 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build windows
+
+package notify
+
+import (
+	"errors"
+	"runtime"
+	"sync"
+	"sync/atomic"
+	"syscall"
+	"unsafe"
+)
+
+// readBufferSize defines the size of an array in which read statuses are stored.
+// The buffer have to be DWORD-aligned and, if notify is used in monitoring a
+// directory over the network, its size must not be greater than 64KB. Each of
+// watched directories uses its own buffer for storing events.
+const readBufferSize = 4096
+
+// Since all operations which go through the Windows completion routine are done
+// asynchronously, filter may set one of the constants belor. They were defined
+// in order to distinguish whether current folder should be re-registered in
+// ReadDirectoryChangesW function or some control operations need to be executed.
+const (
+	stateRewatch uint32 = 1 << (28 + iota)
+	stateUnwatch
+	stateCPClose
+)
+
+// Filter used in current implementation was split into four segments:
+//  - bits  0-11 store ReadDirectoryChangesW filters,
+//  - bits 12-19 store File notify actions,
+//  - bits 20-27 store notify specific events and flags,
+//  - bits 28-31 store states which are used in loop's FSM.
+// Constants below are used as masks to retrieve only specific filter parts.
+const (
+	onlyNotifyChanges uint32 = 0x00000FFF
+	onlyNGlobalEvents uint32 = 0x0FF00000
+	onlyMachineStates uint32 = 0xF0000000
+)
+
+// grip represents a single watched directory. It stores the data required by
+// ReadDirectoryChangesW function. Only the filter, recursive, and handle members
+// may by modified by watcher implementation. Rest of the them have to remain
+// constant since they are used by Windows completion routine. This indicates that
+// grip can be removed only when all operations on the file handle are finished.
+type grip struct {
+	handle    syscall.Handle
+	filter    uint32
+	recursive bool
+	pathw     []uint16
+	buffer    [readBufferSize]byte
+	parent    *watched
+	ovlapped  *overlappedEx
+}
+
+// overlappedEx stores information used in asynchronous input and output.
+// Additionally, overlappedEx contains a pointer to 'grip' item which is used in
+// order to gather the structure in which the overlappedEx object was created.
+type overlappedEx struct {
+	syscall.Overlapped
+	parent *grip
+}
+
+// newGrip creates a new file handle that can be used in overlapped operations.
+// Then, the handle is associated with I/O completion port 'cph' and its value
+// is stored in newly created 'grip' object.
+func newGrip(cph syscall.Handle, parent *watched, filter uint32) (*grip, error) {
+	g := &grip{
+		handle:    syscall.InvalidHandle,
+		filter:    filter,
+		recursive: parent.recursive,
+		pathw:     parent.pathw,
+		parent:    parent,
+		ovlapped:  &overlappedEx{},
+	}
+	if err := g.register(cph); err != nil {
+		return nil, err
+	}
+	g.ovlapped.parent = g
+	return g, nil
+}
+
+// NOTE : Thread safe
+func (g *grip) register(cph syscall.Handle) (err error) {
+	if g.handle, err = syscall.CreateFile(
+		&g.pathw[0],
+		syscall.FILE_LIST_DIRECTORY,
+		syscall.FILE_SHARE_READ|syscall.FILE_SHARE_WRITE|syscall.FILE_SHARE_DELETE,
+		nil,
+		syscall.OPEN_EXISTING,
+		syscall.FILE_FLAG_BACKUP_SEMANTICS|syscall.FILE_FLAG_OVERLAPPED,
+		0,
+	); err != nil {
+		return
+	}
+	if _, err = syscall.CreateIoCompletionPort(g.handle, cph, 0, 0); err != nil {
+		syscall.CloseHandle(g.handle)
+		return
+	}
+	return g.readDirChanges()
+}
+
+// readDirChanges tells the system to store file change information in grip's
+// buffer. Directory changes that occur between calls to this function are added
+// to the buffer and then, returned with the next call.
+func (g *grip) readDirChanges() error {
+	return syscall.ReadDirectoryChanges(
+		g.handle,
+		&g.buffer[0],
+		uint32(unsafe.Sizeof(g.buffer)),
+		g.recursive,
+		encode(g.filter),
+		nil,
+		(*syscall.Overlapped)(unsafe.Pointer(g.ovlapped)),
+		0,
+	)
+}
+
+// encode transforms a generic filter, which contains platform independent and
+// implementation specific bit fields, to value that can be used as NotifyFilter
+// parameter in ReadDirectoryChangesW function.
+func encode(filter uint32) uint32 {
+	e := Event(filter & (onlyNGlobalEvents | onlyNotifyChanges))
+	if e&dirmarker != 0 {
+		return uint32(FileNotifyChangeDirName)
+	}
+	if e&Create != 0 {
+		e = (e ^ Create) | FileNotifyChangeFileName
+	}
+	if e&Remove != 0 {
+		e = (e ^ Remove) | FileNotifyChangeFileName
+	}
+	if e&Write != 0 {
+		e = (e ^ Write) | FileNotifyChangeAttributes | FileNotifyChangeSize |
+			FileNotifyChangeCreation | FileNotifyChangeSecurity
+	}
+	if e&Rename != 0 {
+		e = (e ^ Rename) | FileNotifyChangeFileName
+	}
+	return uint32(e)
+}
+
+// watched is made in order to check whether an action comes from a directory or
+// file. This approach requires two file handlers per single monitored folder. The
+// second grip handles actions which include creating or deleting a directory. If
+// these processes are not monitored, only the first grip is created.
+type watched struct {
+	filter    uint32
+	recursive bool
+	count     uint8
+	pathw     []uint16
+	digrip    [2]*grip
+}
+
+// newWatched creates a new watched instance. It splits the filter variable into
+// two parts. The first part is responsible for watching all events which can be
+// created for a file in watched directory structure and the second one watches
+// only directory Create/Remove actions. If all operations succeed, the Create
+// message is sent to I/O completion port queue for further processing.
+func newWatched(cph syscall.Handle, filter uint32, recursive bool,
+	path string) (wd *watched, err error) {
+	wd = &watched{
+		filter:    filter,
+		recursive: recursive,
+	}
+	if wd.pathw, err = syscall.UTF16FromString(path); err != nil {
+		return
+	}
+	if err = wd.recreate(cph); err != nil {
+		return
+	}
+	return wd, nil
+}
+
+// TODO : doc
+func (wd *watched) recreate(cph syscall.Handle) (err error) {
+	filefilter := wd.filter &^ uint32(FileNotifyChangeDirName)
+	if err = wd.updateGrip(0, cph, filefilter == 0, filefilter); err != nil {
+		return
+	}
+	dirfilter := wd.filter & uint32(FileNotifyChangeDirName|Create|Remove)
+	if err = wd.updateGrip(1, cph, dirfilter == 0, wd.filter|uint32(dirmarker)); err != nil {
+		return
+	}
+	wd.filter &^= onlyMachineStates
+	return
+}
+
+// TODO : doc
+func (wd *watched) updateGrip(idx int, cph syscall.Handle, reset bool,
+	newflag uint32) (err error) {
+	if reset {
+		wd.digrip[idx] = nil
+	} else {
+		if wd.digrip[idx] == nil {
+			if wd.digrip[idx], err = newGrip(cph, wd, newflag); err != nil {
+				wd.closeHandle()
+				return
+			}
+		} else {
+			wd.digrip[idx].filter = newflag
+			wd.digrip[idx].recursive = wd.recursive
+			if err = wd.digrip[idx].register(cph); err != nil {
+				wd.closeHandle()
+				return
+			}
+		}
+		wd.count++
+	}
+	return
+}
+
+// closeHandle closes handles that are stored in digrip array. Function always
+// tries to close all of the handlers before it exits, even when there are errors
+// returned from the operating system kernel.
+func (wd *watched) closeHandle() (err error) {
+	for _, g := range wd.digrip {
+		if g != nil && g.handle != syscall.InvalidHandle {
+			switch suberr := syscall.CloseHandle(g.handle); {
+			case suberr == nil:
+				g.handle = syscall.InvalidHandle
+			case err == nil:
+				err = suberr
+			}
+		}
+	}
+	return
+}
+
+// watcher implements Watcher interface. It stores a set of watched directories.
+// All operations which remove watched objects from map `m` must be performed in
+// loop goroutine since these structures are used internally by operating system.
+type readdcw struct {
+	sync.Mutex
+	m     map[string]*watched
+	cph   syscall.Handle
+	start bool
+	wg    sync.WaitGroup
+	c     chan<- EventInfo
+}
+
+// NewWatcher creates new non-recursive watcher backed by ReadDirectoryChangesW.
+func newWatcher(c chan<- EventInfo) watcher {
+	r := &readdcw{
+		m:   make(map[string]*watched),
+		cph: syscall.InvalidHandle,
+		c:   c,
+	}
+	runtime.SetFinalizer(r, func(r *readdcw) {
+		if r.cph != syscall.InvalidHandle {
+			syscall.CloseHandle(r.cph)
+		}
+	})
+	return r
+}
+
+// Watch implements notify.Watcher interface.
+func (r *readdcw) Watch(path string, event Event) error {
+	return r.watch(path, event, false)
+}
+
+// RecursiveWatch implements notify.RecursiveWatcher interface.
+func (r *readdcw) RecursiveWatch(path string, event Event) error {
+	return r.watch(path, event, true)
+}
+
+// watch inserts a directory to the group of watched folders. If watched folder
+// already exists, function tries to rewatch it with new filters(NOT VALID). Moreover,
+// watch starts the main event loop goroutine when called for the first time.
+func (r *readdcw) watch(path string, event Event, recursive bool) (err error) {
+	if event&^(All|fileNotifyChangeAll) != 0 {
+		return errors.New("notify: unknown event")
+	}
+	r.Lock()
+	wd, ok := r.m[path]
+	r.Unlock()
+	if !ok {
+		if err = r.lazyinit(); err != nil {
+			return
+		}
+		r.Lock()
+		defer r.Unlock()
+		if wd, ok = r.m[path]; ok {
+			dbgprint("watch: exists already")
+			return
+		}
+		if wd, err = newWatched(r.cph, uint32(event), recursive, path); err != nil {
+			return
+		}
+		r.m[path] = wd
+		dbgprint("watch: new watch added")
+	} else {
+		dbgprint("watch: exists already")
+	}
+	return nil
+}
+
+// lazyinit creates an I/O completion port and starts the main event processing
+// loop. This method uses Double-Checked Locking optimization.
+func (r *readdcw) lazyinit() (err error) {
+	invalid := uintptr(syscall.InvalidHandle)
+	if atomic.LoadUintptr((*uintptr)(&r.cph)) == invalid {
+		r.Lock()
+		defer r.Unlock()
+		if atomic.LoadUintptr((*uintptr)(&r.cph)) == invalid {
+			cph := syscall.InvalidHandle
+			if cph, err = syscall.CreateIoCompletionPort(cph, 0, 0, 0); err != nil {
+				return
+			}
+			r.cph, r.start = cph, true
+			go r.loop()
+		}
+	}
+	return
+}
+
+// TODO(pknap) : doc
+func (r *readdcw) loop() {
+	var n, key uint32
+	var overlapped *syscall.Overlapped
+	for {
+		err := syscall.GetQueuedCompletionStatus(r.cph, &n, &key, &overlapped, syscall.INFINITE)
+		if key == stateCPClose {
+			r.Lock()
+			handle := r.cph
+			r.cph = syscall.InvalidHandle
+			r.Unlock()
+			syscall.CloseHandle(handle)
+			r.wg.Done()
+			return
+		}
+		if overlapped == nil {
+			// TODO: check key == rewatch delete or 0(panic)
+			continue
+		}
+		overEx := (*overlappedEx)(unsafe.Pointer(overlapped))
+		if n != 0 {
+			r.loopevent(n, overEx)
+			if err = overEx.parent.readDirChanges(); err != nil {
+				// TODO: error handling
+			}
+		}
+		r.loopstate(overEx)
+	}
+}
+
+// TODO(pknap) : doc
+func (r *readdcw) loopstate(overEx *overlappedEx) {
+	r.Lock()
+	defer r.Unlock()
+	filter := overEx.parent.parent.filter
+	if filter&onlyMachineStates == 0 {
+		return
+	}
+	if overEx.parent.parent.count--; overEx.parent.parent.count == 0 {
+		switch filter & onlyMachineStates {
+		case stateRewatch:
+			dbgprint("loopstate rewatch")
+			overEx.parent.parent.recreate(r.cph)
+		case stateUnwatch:
+			dbgprint("loopstate unwatch")
+			delete(r.m, syscall.UTF16ToString(overEx.parent.pathw))
+		case stateCPClose:
+		default:
+			panic(`notify: windows loopstate logic error`)
+		}
+	}
+}
+
+// TODO(pknap) : doc
+func (r *readdcw) loopevent(n uint32, overEx *overlappedEx) {
+	events := []*event{}
+	var currOffset uint32
+	for {
+		raw := (*syscall.FileNotifyInformation)(unsafe.Pointer(&overEx.parent.buffer[currOffset]))
+		name := syscall.UTF16ToString((*[syscall.MAX_LONG_PATH]uint16)(unsafe.Pointer(&raw.FileName))[:raw.FileNameLength>>1])
+		events = append(events, &event{
+			pathw:  overEx.parent.pathw,
+			filter: overEx.parent.filter,
+			action: raw.Action,
+			name:   name,
+		})
+		if raw.NextEntryOffset == 0 {
+			break
+		}
+		if currOffset += raw.NextEntryOffset; currOffset >= n {
+			break
+		}
+	}
+	r.send(events)
+}
+
+// TODO(pknap) : doc
+func (r *readdcw) send(es []*event) {
+	for _, e := range es {
+		var syse Event
+		if e.e, syse = decode(e.filter, e.action); e.e == 0 && syse == 0 {
+			continue
+		}
+		switch {
+		case e.action == syscall.FILE_ACTION_MODIFIED:
+			e.ftype = fTypeUnknown
+		case e.filter&uint32(dirmarker) != 0:
+			e.ftype = fTypeDirectory
+		default:
+			e.ftype = fTypeFile
+		}
+		switch {
+		case e.e == 0:
+			e.e = syse
+		case syse != 0:
+			r.c <- &event{
+				pathw:  e.pathw,
+				name:   e.name,
+				ftype:  e.ftype,
+				action: e.action,
+				filter: e.filter,
+				e:      syse,
+			}
+		}
+		r.c <- e
+	}
+}
+
+// Rewatch implements notify.Rewatcher interface.
+func (r *readdcw) Rewatch(path string, oldevent, newevent Event) error {
+	return r.rewatch(path, uint32(oldevent), uint32(newevent), false)
+}
+
+// RecursiveRewatch implements notify.RecursiveRewatcher interface.
+func (r *readdcw) RecursiveRewatch(oldpath, newpath string, oldevent,
+	newevent Event) error {
+	if oldpath != newpath {
+		if err := r.unwatch(oldpath); err != nil {
+			return err
+		}
+		return r.watch(newpath, newevent, true)
+	}
+	return r.rewatch(newpath, uint32(oldevent), uint32(newevent), true)
+}
+
+// TODO : (pknap) doc.
+func (r *readdcw) rewatch(path string, oldevent, newevent uint32, recursive bool) (err error) {
+	if Event(newevent)&^(All|fileNotifyChangeAll) != 0 {
+		return errors.New("notify: unknown event")
+	}
+	var wd *watched
+	r.Lock()
+	defer r.Unlock()
+	if wd, err = r.nonStateWatchedLocked(path); err != nil {
+		return
+	}
+	if wd.filter&(onlyNotifyChanges|onlyNGlobalEvents) != oldevent {
+		panic(`notify: windows re-watcher logic error`)
+	}
+	wd.filter = stateRewatch | newevent
+	wd.recursive, recursive = recursive, wd.recursive
+	if err = wd.closeHandle(); err != nil {
+		wd.filter = oldevent
+		wd.recursive = recursive
+		return
+	}
+	return
+}
+
+// TODO : pknap
+func (r *readdcw) nonStateWatchedLocked(path string) (wd *watched, err error) {
+	wd, ok := r.m[path]
+	if !ok || wd == nil {
+		err = errors.New(`notify: ` + path + ` path is unwatched`)
+		return
+	}
+	if wd.filter&onlyMachineStates != 0 {
+		err = errors.New(`notify: another re/unwatching operation in progress`)
+		return
+	}
+	return
+}
+
+// Unwatch implements notify.Watcher interface.
+func (r *readdcw) Unwatch(path string) error {
+	return r.unwatch(path)
+}
+
+// RecursiveUnwatch implements notify.RecursiveWatcher interface.
+func (r *readdcw) RecursiveUnwatch(path string) error {
+	return r.unwatch(path)
+}
+
+// TODO : pknap
+func (r *readdcw) unwatch(path string) (err error) {
+	var wd *watched
+	r.Lock()
+	defer r.Unlock()
+	if wd, err = r.nonStateWatchedLocked(path); err != nil {
+		return
+	}
+	wd.filter |= stateUnwatch
+	if err = wd.closeHandle(); err != nil {
+		wd.filter &^= stateUnwatch
+		return
+	}
+	if _, attrErr := syscall.GetFileAttributes(&wd.pathw[0]); attrErr != nil {
+		for _, g := range wd.digrip {
+			if g != nil {
+				dbgprint("unwatch: posting")
+				if err = syscall.PostQueuedCompletionStatus(r.cph, 0, 0, (*syscall.Overlapped)(unsafe.Pointer(g.ovlapped))); err != nil {
+					wd.filter &^= stateUnwatch
+					return
+				}
+			}
+		}
+	}
+	return
+}
+
+// Close resets the whole watcher object, closes all existing file descriptors,
+// and sends stateCPClose state as completion key to the main watcher's loop.
+func (r *readdcw) Close() (err error) {
+	r.Lock()
+	if !r.start {
+		r.Unlock()
+		return nil
+	}
+	for _, wd := range r.m {
+		wd.filter &^= onlyMachineStates
+		wd.filter |= stateCPClose
+		if e := wd.closeHandle(); e != nil && err == nil {
+			err = e
+		}
+	}
+	r.start = false
+	r.Unlock()
+	r.wg.Add(1)
+	if e := syscall.PostQueuedCompletionStatus(r.cph, 0, stateCPClose, nil); e != nil && err == nil {
+		return e
+	}
+	r.wg.Wait()
+	return
+}
+
+// decode creates a notify event from both non-raw filter and action which was
+// returned from completion routine. Function may return Event(0) in case when
+// filter was replaced by a new value which does not contain fields that are
+// valid with passed action.
+func decode(filter, action uint32) (Event, Event) {
+	switch action {
+	case syscall.FILE_ACTION_ADDED:
+		return gensys(filter, Create, FileActionAdded)
+	case syscall.FILE_ACTION_REMOVED:
+		return gensys(filter, Remove, FileActionRemoved)
+	case syscall.FILE_ACTION_MODIFIED:
+		return gensys(filter, Write, FileActionModified)
+	case syscall.FILE_ACTION_RENAMED_OLD_NAME:
+		return gensys(filter, Rename, FileActionRenamedOldName)
+	case syscall.FILE_ACTION_RENAMED_NEW_NAME:
+		return gensys(filter, Rename, FileActionRenamedNewName)
+	}
+	panic(`notify: cannot decode internal mask`)
+}
+
+// gensys decides whether the Windows action, system-independent event or both
+// of them should be returned. Since the grip's filter may be atomically changed
+// during watcher lifetime, it is possible that neither Windows nor notify masks
+// are watched by the user when this function is called.
+func gensys(filter uint32, ge, se Event) (gene, syse Event) {
+	isdir := filter&uint32(dirmarker) != 0
+	if isdir && filter&uint32(FileNotifyChangeDirName) != 0 ||
+		!isdir && filter&uint32(FileNotifyChangeFileName) != 0 ||
+		filter&uint32(fileNotifyChangeModified) != 0 {
+		syse = se
+	}
+	if filter&uint32(ge) != 0 {
+		gene = ge
+	}
+	return
+}

vendor/github.com/zillode/notify/watcher_stub.go

@@ -0,0 +1,23 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build !darwin,!linux,!freebsd,!dragonfly,!netbsd,!openbsd,!windows
+// +build !kqueue,!solaris
+
+package notify
+
+import "errors"
+
+type stub struct{ error }
+
+// newWatcher stub.
+func newWatcher(chan<- EventInfo) watcher {
+	return stub{errors.New("notify: not implemented")}
+}
+
+// Following methods implement notify.watcher interface.
+func (s stub) Watch(string, Event) error          { return s }
+func (s stub) Rewatch(string, Event, Event) error { return s }
+func (s stub) Unwatch(string) (err error)         { return s }
+func (s stub) Close() error                       { return s }

vendor/github.com/zillode/notify/watcher_trigger.go

@@ -0,0 +1,449 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build darwin,kqueue dragonfly freebsd netbsd openbsd solaris
+
+// watcher_trigger is used for FEN and kqueue which behave similarly:
+// only files and dirs can be watched directly, but not files inside dirs.
+// As a result Create events have to be generated by implementation when
+// after Write event is returned for watched dir, it is rescanned and Create
+// event is returned for new files and these are automatically added
+// to watchlist. In case of removal of watched directory, native system returns
+// events for all files, but for Rename, they also need to be generated.
+// As a result native system works as something like trigger for rescan,
+// but contains additional data about dir in which changes occurred. For files
+// detailed data is returned.
+// Usage of watcher_trigger requires:
+// - trigger implementation,
+// - encode func,
+// - not2nat, nat2not maps.
+// Required manual operations on filesystem can lead to loss of precision.
+
+package notify
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"syscall"
+)
+
+// trigger is to be implemented by platform implementation like FEN or kqueue.
+type trigger interface {
+	// Close closes watcher's main native file descriptor.
+	Close() error
+	// Stop waiting for new events.
+	Stop() error
+	// Create new instance of watched.
+	NewWatched(string, os.FileInfo) (*watched, error)
+	// Record internally new *watched instance.
+	Record(*watched)
+	// Del removes internal copy of *watched instance.
+	Del(*watched)
+	// Watched returns *watched instance and native events for native type.
+	Watched(interface{}) (*watched, int64, error)
+	// Init initializes native watcher call.
+	Init() error
+	// Watch starts watching provided file/dir.
+	Watch(os.FileInfo, *watched, int64) error
+	// Unwatch stops watching provided file/dir.
+	Unwatch(*watched) error
+	// Wait for new events.
+	Wait() (interface{}, error)
+	// IsStop checks if Wait finished because of request watcher's stop.
+	IsStop(n interface{}, err error) bool
+}
+
+// trgWatched is a the base data structure representing watched file/directory.
+// The platform specific full data structure (watched) must embed this type.
+type trgWatched struct {
+	// p is a path to watched file/directory.
+	p string
+	// fi provides information about watched file/dir.
+	fi os.FileInfo
+	// eDir represents events watched directly.
+	eDir Event
+	// eNonDir represents events watched indirectly.
+	eNonDir Event
+}
+
+// encode Event to native representation. Implementation is to be provided by
+// platform specific implementation.
+var encode func(Event, bool) int64
+
+var (
+	// nat2not matches native events to notify's ones. To be initialized by
+	// platform dependent implementation.
+	nat2not map[Event]Event
+	// not2nat matches notify's events to native ones. To be initialized by
+	// platform dependent implementation.
+	not2nat map[Event]Event
+)
+
+// trg is a main structure implementing watcher.
+type trg struct {
+	sync.Mutex
+	// s is a channel used to stop monitoring.
+	s chan struct{}
+	// c is a channel used to pass events further.
+	c chan<- EventInfo
+	// pthLkp is a data structure mapping file names with data about watching
+	// represented by them files/directories.
+	pthLkp map[string]*watched
+	// t is a platform dependent implementation of trigger.
+	t trigger
+}
+
+// newWatcher returns new watcher's implementation.
+func newWatcher(c chan<- EventInfo) watcher {
+	t := &trg{
+		s:      make(chan struct{}, 1),
+		pthLkp: make(map[string]*watched, 0),
+		c:      c,
+	}
+	t.t = newTrigger(t.pthLkp)
+	if err := t.t.Init(); err != nil {
+		panic(err)
+	}
+	go t.monitor()
+	return t
+}
+
+// Close implements watcher.
+func (t *trg) Close() (err error) {
+	t.Lock()
+	if err = t.t.Stop(); err != nil {
+		t.Unlock()
+		return
+	}
+	<-t.s
+	var e error
+	for _, w := range t.pthLkp {
+		if e = t.unwatch(w.p, w.fi); e != nil {
+			dbgprintf("trg: unwatch %q failed: %q\n", w.p, e)
+			err = nonil(err, e)
+		}
+	}
+	if e = t.t.Close(); e != nil {
+		dbgprintf("trg: closing native watch failed: %q\n", e)
+		err = nonil(err, e)
+	}
+	if remaining := len(t.pthLkp); remaining != 0 {
+		err = nonil(err, fmt.Errorf("Not all watches were removed: len(t.pthLkp) == %v", len(t.pthLkp)))
+	}
+	t.Unlock()
+	return
+}
+
+// send reported events one by one through chan.
+func (t *trg) send(evn []event) {
+	for i := range evn {
+		t.c <- &evn[i]
+	}
+}
+
+// singlewatch starts to watch given p file/directory.
+func (t *trg) singlewatch(p string, e Event, direct mode, fi os.FileInfo) (err error) {
+	w, ok := t.pthLkp[p]
+	if !ok {
+		if w, err = t.t.NewWatched(p, fi); err != nil {
+			return
+		}
+	}
+	switch direct {
+	case dir:
+		w.eDir |= e
+	case ndir:
+		w.eNonDir |= e
+	case both:
+		w.eDir |= e
+		w.eNonDir |= e
+	}
+	if err = t.t.Watch(fi, w, encode(w.eDir|w.eNonDir, fi.IsDir())); err != nil {
+		return
+	}
+	if !ok {
+		t.t.Record(w)
+		return nil
+	}
+	return errAlreadyWatched
+}
+
+// decode converts event received from native to notify.Event
+// representation taking into account requested events (w).
+func decode(o int64, w Event) (e Event) {
+	for f, n := range nat2not {
+		if o&int64(f) != 0 {
+			if w&f != 0 {
+				e |= f
+			}
+			if w&n != 0 {
+				e |= n
+			}
+		}
+	}
+
+	return
+}
+
+func (t *trg) watch(p string, e Event, fi os.FileInfo) error {
+	if err := t.singlewatch(p, e, dir, fi); err != nil {
+		if err != errAlreadyWatched {
+			return err
+		}
+	}
+	if fi.IsDir() {
+		err := t.walk(p, func(fi os.FileInfo) (err error) {
+			if err = t.singlewatch(filepath.Join(p, fi.Name()), e, ndir,
+				fi); err != nil {
+				if err != errAlreadyWatched {
+					return
+				}
+			}
+			return nil
+		})
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// walk runs f func on each file/dir from p directory.
+func (t *trg) walk(p string, fn func(os.FileInfo) error) error {
+	fp, err := os.Open(p)
+	if err != nil {
+		return err
+	}
+	ls, err := fp.Readdir(0)
+	fp.Close()
+	if err != nil {
+		return err
+	}
+	for i := range ls {
+		if err := fn(ls[i]); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (t *trg) unwatch(p string, fi os.FileInfo) error {
+	if fi.IsDir() {
+		err := t.walk(p, func(fi os.FileInfo) error {
+			err := t.singleunwatch(filepath.Join(p, fi.Name()), ndir)
+			if err != errNotWatched {
+				return err
+			}
+			return nil
+		})
+		if err != nil {
+			return err
+		}
+	}
+	return t.singleunwatch(p, dir)
+}
+
+// Watch implements Watcher interface.
+func (t *trg) Watch(p string, e Event) error {
+	fi, err := os.Stat(p)
+	if err != nil {
+		return err
+	}
+	t.Lock()
+	err = t.watch(p, e, fi)
+	t.Unlock()
+	return err
+}
+
+// Unwatch implements Watcher interface.
+func (t *trg) Unwatch(p string) error {
+	fi, err := os.Stat(p)
+	if err != nil {
+		return err
+	}
+	t.Lock()
+	err = t.unwatch(p, fi)
+	t.Unlock()
+	return err
+}
+
+// Rewatch implements Watcher interface.
+//
+// TODO(rjeczalik): This is a naive hack. Rewrite might help.
+func (t *trg) Rewatch(p string, _, e Event) error {
+	fi, err := os.Stat(p)
+	if err != nil {
+		return err
+	}
+	t.Lock()
+	if err = t.unwatch(p, fi); err == nil {
+		// TODO(rjeczalik): If watch fails then we leave trigger in inconsistent
+		// state. Handle? Panic? Native version of rewatch?
+		err = t.watch(p, e, fi)
+	}
+	t.Unlock()
+	return nil
+}
+
+func (*trg) file(w *watched, n interface{}, e Event) (evn []event) {
+	evn = append(evn, event{w.p, e, w.fi.IsDir(), n})
+	return
+}
+
+func (t *trg) dir(w *watched, n interface{}, e, ge Event) (evn []event) {
+	// If it's dir and delete we have to send it and continue, because
+	// other processing relies on opening (in this case not existing) dir.
+	// Events for contents of this dir are reported by native impl.
+	// However events for rename must be generated for all monitored files
+	// inside of moved directory, because native impl does not report it independently
+	// for each file descriptor being moved in result of move action on
+	// parent directory.
+	if (ge & (not2nat[Rename] | not2nat[Remove])) != 0 {
+		// Write is reported also for Remove on directory. Because of that
+		// we have to filter it out explicitly.
+		evn = append(evn, event{w.p, e & ^Write & ^not2nat[Write], true, n})
+		if ge&not2nat[Rename] != 0 {
+			for p := range t.pthLkp {
+				if strings.HasPrefix(p, w.p+string(os.PathSeparator)) {
+					if err := t.singleunwatch(p, both); err != nil && err != errNotWatched &&
+						!os.IsNotExist(err) {
+						dbgprintf("trg: failed stop watching moved file (%q): %q\n",
+							p, err)
+					}
+					if (w.eDir|w.eNonDir)&(not2nat[Rename]|Rename) != 0 {
+						evn = append(evn, event{
+							p, (w.eDir | w.eNonDir) & e &^ Write &^ not2nat[Write],
+							w.fi.IsDir(), nil,
+						})
+					}
+				}
+			}
+		}
+		t.t.Del(w)
+		return
+	}
+	if (ge & not2nat[Write]) != 0 {
+		switch err := t.walk(w.p, func(fi os.FileInfo) error {
+			p := filepath.Join(w.p, fi.Name())
+			switch err := t.singlewatch(p, w.eDir, ndir, fi); {
+			case os.IsNotExist(err) && ((w.eDir & Remove) != 0):
+				evn = append(evn, event{p, Remove, fi.IsDir(), n})
+			case err == errAlreadyWatched:
+			case err != nil:
+				dbgprintf("trg: watching %q failed: %q", p, err)
+			case (w.eDir & Create) != 0:
+				evn = append(evn, event{p, Create, fi.IsDir(), n})
+			default:
+			}
+			return nil
+		}); {
+		case os.IsNotExist(err):
+			return
+		case err != nil:
+			dbgprintf("trg: dir processing failed: %q", err)
+		default:
+		}
+	}
+	return
+}
+
+type mode uint
+
+const (
+	dir mode = iota
+	ndir
+	both
+)
+
+// unwatch stops watching p file/directory.
+func (t *trg) singleunwatch(p string, direct mode) error {
+	w, ok := t.pthLkp[p]
+	if !ok {
+		return errNotWatched
+	}
+	switch direct {
+	case dir:
+		w.eDir = 0
+	case ndir:
+		w.eNonDir = 0
+	case both:
+		w.eDir, w.eNonDir = 0, 0
+	}
+	if err := t.t.Unwatch(w); err != nil {
+		return err
+	}
+	if w.eNonDir|w.eDir != 0 {
+		mod := dir
+		if w.eNonDir != 0 {
+			mod = ndir
+		}
+		if err := t.singlewatch(p, w.eNonDir|w.eDir, mod,
+			w.fi); err != nil && err != errAlreadyWatched {
+			return err
+		}
+	} else {
+		t.t.Del(w)
+	}
+	return nil
+}
+
+func (t *trg) monitor() {
+	var (
+		n   interface{}
+		err error
+	)
+	for {
+		switch n, err = t.t.Wait(); {
+		case err == syscall.EINTR:
+		case t.t.IsStop(n, err):
+			t.s <- struct{}{}
+			return
+		case err != nil:
+			dbgprintf("trg: failed to read events: %q\n", err)
+		default:
+			t.send(t.process(n))
+		}
+	}
+}
+
+// process event returned by native call.
+func (t *trg) process(n interface{}) (evn []event) {
+	t.Lock()
+	w, ge, err := t.t.Watched(n)
+	if err != nil {
+		t.Unlock()
+		dbgprintf("trg: %v event lookup failed: %q", Event(ge), err)
+		return
+	}
+
+	e := decode(ge, w.eDir|w.eNonDir)
+	if ge&int64(not2nat[Remove]|not2nat[Rename]) == 0 {
+		switch fi, err := os.Stat(w.p); {
+		case err != nil:
+		default:
+			if err = t.t.Watch(fi, w, encode(w.eDir|w.eNonDir, fi.IsDir())); err != nil {
+				dbgprintf("trg: %q is no longer watched: %q", w.p, err)
+				t.t.Del(w)
+			}
+		}
+	}
+	if e == Event(0) && (!w.fi.IsDir() || (ge&int64(not2nat[Write])) == 0) {
+		t.Unlock()
+		return
+	}
+
+	if w.fi.IsDir() {
+		evn = append(evn, t.dir(w, n, e, Event(ge))...)
+	} else {
+		evn = append(evn, t.file(w, n, e)...)
+	}
+	if Event(ge)&(not2nat[Remove]|not2nat[Rename]) != 0 {
+		t.t.Del(w)
+	}
+	t.Unlock()
+	return
+}

vendor/github.com/zillode/notify/watchpoint.go

@@ -0,0 +1,103 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+package notify
+
+// EventDiff describes a change to an event set - EventDiff[0] is an old state,
+// while EventDiff[1] is a new state. If event set has not changed (old == new),
+// functions typically return the None value.
+type eventDiff [2]Event
+
+func (diff eventDiff) Event() Event {
+	return diff[1] &^ diff[0]
+}
+
+// Watchpoint
+//
+// The nil key holds total event set - logical sum for all registered events.
+// It speeds up computing EventDiff for Add method.
+//
+// The rec key holds an event set for a watchpoints created by RecursiveWatch
+// for a Watcher implementation which is not natively recursive.
+type watchpoint map[chan<- EventInfo]Event
+
+// None is an empty event diff, think null object.
+var none eventDiff
+
+// rec is just a placeholder
+var rec = func() (ch chan<- EventInfo) {
+	ch = make(chan<- EventInfo)
+	close(ch)
+	return
+}()
+
+func (wp watchpoint) dryAdd(ch chan<- EventInfo, e Event) eventDiff {
+	if e &^= internal; wp[ch]&e == e {
+		return none
+	}
+	total := wp[ch] &^ internal
+	return eventDiff{total, total | e}
+}
+
+// Add assumes neither c nor e are nil or zero values.
+func (wp watchpoint) Add(c chan<- EventInfo, e Event) (diff eventDiff) {
+	wp[c] |= e
+	diff[0] = wp[nil]
+	diff[1] = diff[0] | e
+	wp[nil] = diff[1] &^ omit
+	// Strip diff from internal events.
+	diff[0] &^= internal
+	diff[1] &^= internal
+	if diff[0] == diff[1] {
+		return none
+	}
+	return
+}
+
+func (wp watchpoint) Del(c chan<- EventInfo, e Event) (diff eventDiff) {
+	wp[c] &^= e
+	if wp[c] == 0 {
+		delete(wp, c)
+	}
+	diff[0] = wp[nil]
+	delete(wp, nil)
+	if len(wp) != 0 {
+		// Recalculate total event set.
+		for _, e := range wp {
+			diff[1] |= e
+		}
+		wp[nil] = diff[1] &^ omit
+	}
+	// Strip diff from internal events.
+	diff[0] &^= internal
+	diff[1] &^= internal
+	if diff[0] == diff[1] {
+		return none
+	}
+	return
+}
+
+func (wp watchpoint) Dispatch(ei EventInfo, extra Event) {
+	e := eventmask(ei, extra)
+	if !matches(wp[nil], e) {
+		return
+	}
+	for ch, eset := range wp {
+		if ch != nil && matches(eset, e) {
+			select {
+			case ch <- ei:
+			default: // Drop event if receiver is too slow
+				dbgprintf("dropped %s on %q: receiver too slow", ei.Event(), ei.Path())
+			}
+		}
+	}
+}
+
+func (wp watchpoint) Total() Event {
+	return wp[nil] &^ internal
+}
+
+func (wp watchpoint) IsRecursive() bool {
+	return wp[nil]&recursive != 0
+}

vendor/github.com/zillode/notify/watchpoint_other.go

@@ -0,0 +1,23 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build !windows
+
+package notify
+
+// eventmask uses ei to create a new event which contains internal flags used by
+// notify package logic.
+func eventmask(ei EventInfo, extra Event) Event {
+	return ei.Event() | extra
+}
+
+// matches reports a match only when:
+//
+//   - for user events, when event is present in the given set
+//   - for internal events, when additionally both event and set have omit bit set
+//
+// Internal events must not be sent to user channels and vice versa.
+func matches(set, event Event) bool {
+	return (set&omit)^(event&omit) == 0 && set&event == event
+}

vendor/github.com/zillode/notify/watchpoint_readdcw.go

@@ -0,0 +1,38 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build windows
+
+package notify
+
+// eventmask uses ei to create a new event which contains internal flags used by
+// notify package logic. If one of FileAction* masks is detected, this function
+// adds corresponding FileNotifyChange* values. This allows non registered
+// FileAction* events to be passed on.
+func eventmask(ei EventInfo, extra Event) (e Event) {
+	if e = ei.Event() | extra; e&fileActionAll != 0 {
+		if ev, ok := ei.(*event); ok {
+			switch ev.ftype {
+			case fTypeFile:
+				e |= FileNotifyChangeFileName
+			case fTypeDirectory:
+				e |= FileNotifyChangeDirName
+			case fTypeUnknown:
+				e |= fileNotifyChangeModified
+			}
+			return e &^ fileActionAll
+		}
+	}
+	return
+}
+
+// matches reports a match only when:
+//
+//   - for user events, when event is present in the given set
+//   - for internal events, when additionally both event and set have omit bit set
+//
+// Internal events must not be sent to user channels and vice versa.
+func matches(set, event Event) bool {
+	return (set&omit)^(event&omit) == 0 && (set&event == event || set&fileNotifyChangeModified&event != 0)
+}

vendor/manifest

@@ -446,6 +446,14 @@
 			"branch": "master",
 			"notests": true
 		},
+		{
+			"importpath": "github.com/zillode/notify",
+			"repository": "https://github.com/zillode/notify",
+			"vcs": "git",
+			"revision": "54e3093eb7377fd139c4605f475cc78e83610b9d",
+			"branch": "master",
+			"notests": true
+		},
 		{
 			"importpath": "golang.org/x/crypto/bcrypt",
 			"repository": "https://go.googlesource.com/crypto",