syncthing/lib/ignore/ignore.go

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// Copyright (C) 2014 The Syncthing Authors.
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//
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// 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 ignore
import (
"bufio"
"bytes"
"crypto/md5"
"fmt"
"io"
"os"
"path/filepath"
"runtime"
"strings"
"time"
"github.com/gobwas/glob"
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"github.com/syncthing/syncthing/lib/sync"
)
const (
resultNotMatched Result = 0
resultInclude Result = 1 << iota
resultDeletable = 1 << iota
resultFoldCase = 1 << iota
)
type Pattern struct {
pattern string
match glob.Glob
result Result
}
func (p Pattern) String() string {
ret := p.pattern
if p.result&resultInclude != resultInclude {
ret = "!" + ret
}
if p.result&resultFoldCase == resultFoldCase {
ret = "(?i)" + ret
}
if p.result&resultDeletable == resultDeletable {
ret = "(?d)" + ret
}
return ret
}
type Result uint8
func (r Result) IsIgnored() bool {
return r&resultInclude == resultInclude
}
func (r Result) IsDeletable() bool {
return r.IsIgnored() && r&resultDeletable == resultDeletable
}
func (r Result) IsCaseFolded() bool {
return r&resultFoldCase == resultFoldCase
}
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type Matcher struct {
patterns []Pattern
withCache bool
matches *cache
curHash string
stop chan struct{}
modtimes map[string]time.Time
mut sync.Mutex
}
func New(withCache bool) *Matcher {
m := &Matcher{
withCache: withCache,
stop: make(chan struct{}),
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mut: sync.NewMutex(),
}
if withCache {
go m.clean(2 * time.Hour)
}
return m
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}
func (m *Matcher) Load(file string) error {
m.mut.Lock()
defer m.mut.Unlock()
if m.patternsUnchanged(file) {
return nil
}
fd, err := os.Open(file)
if err != nil {
m.parseLocked(&bytes.Buffer{}, file)
return err
}
defer fd.Close()
info, err := fd.Stat()
if err != nil {
m.parseLocked(&bytes.Buffer{}, file)
return err
}
m.modtimes = map[string]time.Time{
file: info.ModTime(),
}
return m.parseLocked(fd, file)
}
func (m *Matcher) Parse(r io.Reader, file string) error {
m.mut.Lock()
defer m.mut.Unlock()
return m.parseLocked(r, file)
}
func (m *Matcher) parseLocked(r io.Reader, file string) error {
patterns, err := parseIgnoreFile(r, file, m.modtimes)
// Error is saved and returned at the end. We process the patterns
// (possibly blank) anyway.
newHash := hashPatterns(patterns)
if newHash == m.curHash {
// We've already loaded exactly these patterns.
return err
}
m.curHash = newHash
m.patterns = patterns
if m.withCache {
m.matches = newCache(patterns)
}
return err
}
// patternsUnchanged returns true if none of the files making up the loaded
// patterns have changed since last check.
func (m *Matcher) patternsUnchanged(file string) bool {
if _, ok := m.modtimes[file]; !ok {
return false
}
for filename, modtime := range m.modtimes {
info, err := os.Stat(filename)
if err != nil {
return false
}
if !info.ModTime().Equal(modtime) {
return false
}
}
return true
}
func (m *Matcher) Match(file string) (result Result) {
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if m == nil {
return resultNotMatched
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}
m.mut.Lock()
defer m.mut.Unlock()
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if len(m.patterns) == 0 {
return resultNotMatched
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}
if m.matches != nil {
// Check the cache for a known result.
res, ok := m.matches.get(file)
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if ok {
return res
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}
// Update the cache with the result at return time
defer func() {
m.matches.set(file, result)
}()
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}
// Check all the patterns for a match.
file = filepath.ToSlash(file)
var lowercaseFile string
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for _, pattern := range m.patterns {
if pattern.result.IsCaseFolded() {
if lowercaseFile == "" {
lowercaseFile = strings.ToLower(file)
}
if pattern.match.Match(lowercaseFile) {
return pattern.result
}
} else {
if pattern.match.Match(file) {
return pattern.result
}
}
}
// Default to not matching.
return resultNotMatched
}
// Patterns return a list of the loaded patterns, as they've been parsed
func (m *Matcher) Patterns() []string {
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if m == nil {
return nil
}
m.mut.Lock()
defer m.mut.Unlock()
patterns := make([]string, len(m.patterns))
for i, pat := range m.patterns {
patterns[i] = pat.String()
}
return patterns
}
func (m *Matcher) Hash() string {
m.mut.Lock()
defer m.mut.Unlock()
return m.curHash
}
func (m *Matcher) Stop() {
close(m.stop)
}
func (m *Matcher) clean(d time.Duration) {
t := time.NewTimer(d / 2)
for {
select {
case <-m.stop:
return
case <-t.C:
m.mut.Lock()
if m.matches != nil {
m.matches.clean(d)
}
t.Reset(d / 2)
m.mut.Unlock()
}
}
}
func hashPatterns(patterns []Pattern) string {
h := md5.New()
for _, pat := range patterns {
h.Write([]byte(pat.String()))
h.Write([]byte("\n"))
}
return fmt.Sprintf("%x", h.Sum(nil))
}
func loadIgnoreFile(file string, modtimes map[string]time.Time) ([]Pattern, error) {
if _, ok := modtimes[file]; ok {
return nil, fmt.Errorf("Multiple include of ignore file %q", file)
}
fd, err := os.Open(file)
if err != nil {
return nil, err
}
defer fd.Close()
info, err := fd.Stat()
if err != nil {
return nil, err
}
modtimes[file] = info.ModTime()
return parseIgnoreFile(fd, file, modtimes)
}
func parseIgnoreFile(fd io.Reader, currentFile string, modtimes map[string]time.Time) ([]Pattern, error) {
var patterns []Pattern
defaultResult := resultInclude
if runtime.GOOS == "darwin" || runtime.GOOS == "windows" {
defaultResult |= resultFoldCase
}
addPattern := func(line string) error {
pattern := Pattern{
result: defaultResult,
}
// Allow prefixes to be specified in any order, but only once.
var seenPrefix [3]bool
for {
if strings.HasPrefix(line, "!") && !seenPrefix[0] {
seenPrefix[0] = true
line = line[1:]
pattern.result ^= resultInclude
} else if strings.HasPrefix(line, "(?i)") && !seenPrefix[1] {
seenPrefix[1] = true
pattern.result |= resultFoldCase
line = line[4:]
} else if strings.HasPrefix(line, "(?d)") && !seenPrefix[2] {
seenPrefix[2] = true
pattern.result |= resultDeletable
line = line[4:]
} else {
break
}
}
if pattern.result.IsCaseFolded() {
line = strings.ToLower(line)
}
pattern.pattern = line
var err error
if strings.HasPrefix(line, "/") {
// Pattern is rooted in the current dir only
pattern.match, err = glob.Compile(line[1:], '/')
if err != nil {
return fmt.Errorf("invalid pattern %q in ignore file (%v)", line, err)
}
patterns = append(patterns, pattern)
} else if strings.HasPrefix(line, "**/") {
// Add the pattern as is, and without **/ so it matches in current dir
pattern.match, err = glob.Compile(line, '/')
if err != nil {
return fmt.Errorf("invalid pattern %q in ignore file (%v)", line, err)
}
patterns = append(patterns, pattern)
line = line[3:]
pattern.pattern = line
pattern.match, err = glob.Compile(line, '/')
if err != nil {
return fmt.Errorf("invalid pattern %q in ignore file (%v)", line, err)
}
patterns = append(patterns, pattern)
} else if strings.HasPrefix(line, "#include ") {
includeRel := line[len("#include "):]
includeFile := filepath.Join(filepath.Dir(currentFile), includeRel)
includes, err := loadIgnoreFile(includeFile, modtimes)
if err != nil {
return fmt.Errorf("include of %q: %v", includeRel, err)
}
patterns = append(patterns, includes...)
} else {
// Path name or pattern, add it so it matches files both in
// current directory and subdirs.
pattern.match, err = glob.Compile(line, '/')
if err != nil {
return fmt.Errorf("invalid pattern %q in ignore file (%v)", line, err)
}
patterns = append(patterns, pattern)
line := "**/" + line
pattern.pattern = line
pattern.match, err = glob.Compile(line, '/')
if err != nil {
return fmt.Errorf("invalid pattern %q in ignore file (%v)", line, err)
}
patterns = append(patterns, pattern)
}
return nil
}
scanner := bufio.NewScanner(fd)
var err error
for scanner.Scan() {
line := strings.TrimSpace(scanner.Text())
switch {
case line == "":
continue
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case strings.HasPrefix(line, "//"):
continue
}
line = filepath.ToSlash(line)
switch {
case strings.HasPrefix(line, "#"):
err = addPattern(line)
case strings.HasSuffix(line, "/**"):
err = addPattern(line)
case strings.HasSuffix(line, "/"):
err = addPattern(line + "**")
default:
err = addPattern(line)
if err == nil {
err = addPattern(line + "/**")
}
}
if err != nil {
return nil, err
}
}
return patterns, nil
}
// IsInternal returns true if the file, as a path relative to the folder
// root, represents an internal file that should always be ignored. The file
// path must be clean (i.e., in canonical shortest form).
func IsInternal(file string) bool {
internals := []string{".stfolder", ".stignore", ".stversions"}
pathSep := string(os.PathSeparator)
for _, internal := range internals {
if file == internal {
return true
}
if strings.HasPrefix(file, internal+pathSep) {
return true
}
}
return false
}