syncthing/lib/fs/filesystem.go
Jakob Borg d6fbfc3545 lib/fs, lib/model, lib/scanner: Make scans cancellable (fixes #3965)
The folder already knew how to stop properly, but the fs.Walk() didn't
and can potentially take a very long time. This adds context support to
Walk and the underlying scanning stuff, and passes in an appropriate
context from above. The stop channel in model.folder is replaced with a
context for this purpose.

To test I added an infiniteFS that represents a large amount of data
(not actually infinite, but close) and verify that walking it is
properly stopped. For that to be implemented smoothly I moved out the
Walk function to it's own type, as typically the implementer of a new
filesystem type might not need or want to reimplement Walk.

It's somewhat tricky to test that this actually works properly on the
actual sendReceiveFolder and so on, as those are started from inside the
model and the filesystem isn't easily pluggable etc. Instead I've tested
that part manually by adding a huge folder and verifying that pause,
resume and reconfig do the right things by looking at debug output.

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4117
2017-04-26 00:15:23 +00:00

79 lines
2.2 KiB
Go

// 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 https://mozilla.org/MPL/2.0/.
package fs
import (
"io"
"os"
"path/filepath"
"time"
)
// The Filesystem interface abstracts access to the file system.
type Filesystem interface {
Chmod(name string, mode FileMode) error
Chtimes(name string, atime time.Time, mtime time.Time) error
Create(name string) (File, error)
CreateSymlink(name, target string) error
DirNames(name string) ([]string, error)
Lstat(name string) (FileInfo, error)
Mkdir(name string, perm FileMode) error
Open(name string) (File, error)
ReadSymlink(name string) (string, error)
Remove(name string) error
Rename(oldname, newname string) error
Stat(name string) (FileInfo, error)
SymlinksSupported() bool
Walk(root string, walkFn WalkFunc) error
}
// The File interface abstracts access to a regular file, being a somewhat
// smaller interface than os.File
type File interface {
io.Reader
io.WriterAt
io.Closer
Truncate(size int64) error
Stat() (FileInfo, error)
}
// The FileInfo interface is almost the same as os.FileInfo, but with the
// Sys method removed (as we don't want to expose whatever is underlying)
// and with a couple of convenience methods added.
type FileInfo interface {
// Standard things present in os.FileInfo
Name() string
Mode() FileMode
Size() int64
ModTime() time.Time
IsDir() bool
// Extensions
IsRegular() bool
IsSymlink() bool
}
// FileMode is similar to os.FileMode
type FileMode uint32
// ModePerm is the equivalent of os.ModePerm
const ModePerm = FileMode(os.ModePerm)
// DefaultFilesystem is the fallback to use when nothing explicitly has
// been passed.
var DefaultFilesystem Filesystem = NewWalkFilesystem(NewBasicFilesystem())
// SkipDir is used as a return value from WalkFuncs to indicate that
// the directory named in the call is to be skipped. It is not returned
// as an error by any function.
var SkipDir = filepath.SkipDir
// IsExist is the equivalent of os.IsExist
var IsExist = os.IsExist
// IsNotExist is the equivalent of os.IsNotExist
var IsNotExist = os.IsNotExist