--watch

vendor/github.com/andreaskoch/go-fswatch/file.go

@@ -0,0 +1,192 @@
+// Copyright 2013 Andreas Koch. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package fswatch
+
+import (
+	"fmt"
+	"os"
+	"time"
+)
+
+var numberOfFileWatchers int
+
+func init() {
+	numberOfFolderWatchers = 0
+}
+
+func NumberOfFileWatchers() int {
+	return numberOfFileWatchers
+}
+
+type FileWatcher struct {
+	modified chan bool
+	moved    chan bool
+	stopped  chan bool
+
+	file          string
+	running       bool
+	wasStopped    bool
+	checkInterval time.Duration
+
+	previousModTime time.Time
+}
+
+func NewFileWatcher(filePath string, checkIntervalInSeconds int) *FileWatcher {
+
+	if checkIntervalInSeconds < 1 {
+		panic(fmt.Sprintf("Cannot create a file watcher with a check interval of %v seconds.", checkIntervalInSeconds))
+	}
+
+	return &FileWatcher{
+		modified: make(chan bool),
+		moved:    make(chan bool),
+		stopped:  make(chan bool),
+
+		file:          filePath,
+		checkInterval: time.Duration(checkIntervalInSeconds),
+	}
+}
+
+func (fileWatcher *FileWatcher) String() string {
+	return fmt.Sprintf("Filewatcher %q", fileWatcher.file)
+}
+
+func (fileWatcher *FileWatcher) SetFile(filePath string) {
+	fileWatcher.file = filePath
+}
+
+func (filewatcher *FileWatcher) Modified() chan bool {
+	return filewatcher.modified
+}
+
+func (filewatcher *FileWatcher) Moved() chan bool {
+	return filewatcher.moved
+}
+
+func (filewatcher *FileWatcher) Stopped() chan bool {
+	return filewatcher.stopped
+}
+
+func (fileWatcher *FileWatcher) Start() {
+	fileWatcher.running = true
+	sleepInterval := time.Second * fileWatcher.checkInterval
+
+	go func() {
+
+		// increment watcher count
+		numberOfFileWatchers++
+
+		var modTime time.Time
+		previousModTime := fileWatcher.getPreviousModTime()
+
+		if timeIsSet(previousModTime) {
+			modTime = previousModTime
+		} else {
+			currentModTime, err := getLastModTimeFromFile(fileWatcher.file)
+			if err != nil {
+
+				// send out the notification
+				log("File %q has been moved or is inaccessible.", fileWatcher.file)
+				go func() {
+					fileWatcher.moved <- true
+				}()
+
+				// stop this file watcher
+				fileWatcher.Stop()
+
+			} else {
+
+				modTime = currentModTime
+			}
+
+		}
+
+		for fileWatcher.wasStopped == false {
+
+			newModTime, err := getLastModTimeFromFile(fileWatcher.file)
+			if err != nil {
+
+				// send out the notification
+				log("File %q has been moved.", fileWatcher.file)
+				go func() {
+					fileWatcher.moved <- true
+				}()
+
+				// stop this file watcher
+				fileWatcher.Stop()
+
+				continue
+			}
+
+			// detect changes
+			if modTime.Before(newModTime) {
+
+				// send out the notification
+				log("File %q has been modified.", fileWatcher.file)
+				go func() {
+					fileWatcher.modified <- true
+				}()
+
+			} else {
+
+				log("File %q has not changed.", fileWatcher.file)
+
+			}
+
+			// assign the new modtime
+			modTime = newModTime
+
+			time.Sleep(sleepInterval)
+
+		}
+
+		fileWatcher.running = false
+
+		// capture the entry list for a restart
+		fileWatcher.captureModTime(modTime)
+
+		// inform channel-subscribers
+		go func() {
+			fileWatcher.stopped <- true
+		}()
+
+		// decrement the watch counter
+		numberOfFileWatchers--
+
+		// final log message
+		log("Stopped file watcher %q", fileWatcher.String())
+	}()
+}
+
+func (fileWatcher *FileWatcher) Stop() {
+	log("Stopping file watcher %q", fileWatcher.String())
+	fileWatcher.wasStopped = true
+}
+
+func (fileWatcher *FileWatcher) IsRunning() bool {
+	return fileWatcher.running
+}
+
+func (fileWatcher *FileWatcher) getPreviousModTime() time.Time {
+	return fileWatcher.previousModTime
+}
+
+// Remember the last mod time for a later restart
+func (fileWatcher *FileWatcher) captureModTime(modTime time.Time) {
+	fileWatcher.previousModTime = modTime
+}
+
+func getLastModTimeFromFile(file string) (time.Time, error) {
+	fileInfo, err := os.Stat(file)
+	if err != nil {
+		return time.Time{}, err
+	}
+
+	return fileInfo.ModTime(), nil
+}
+
+func timeIsSet(t time.Time) bool {
+	return time.Time{} == t
+}