hugo/watcher/filenotify/filenotify.go

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// Package filenotify provides a mechanism for watching file(s) for changes.
// Generally leans on fsnotify, but provides a poll-based notifier which fsnotify does not support.
// These are wrapped up in a common interface so that either can be used interchangeably in your code.
//
// This package is adapted from https://github.com/moby/moby/tree/master/pkg/filenotify, Apache-2.0 License.
// Hopefully this can be replaced with an external package sometime in the future, see https://github.com/fsnotify/fsnotify/issues/9
package filenotify
import (
"time"
"github.com/fsnotify/fsnotify"
)
// FileWatcher is an interface for implementing file notification watchers
type FileWatcher interface {
Events() <-chan fsnotify.Event
Errors() <-chan error
Add(name string) error
Remove(name string) error
Close() error
}
// New tries to use an fs-event watcher, and falls back to the poller if there is an error
func New(interval time.Duration) (FileWatcher, error) {
if watcher, err := NewEventWatcher(); err == nil {
return watcher, nil
}
return NewPollingWatcher(interval), nil
}
// NewPollingWatcher returns a poll-based file watcher
func NewPollingWatcher(interval time.Duration) FileWatcher {
return &filePoller{
interval: interval,
done: make(chan struct{}),
events: make(chan fsnotify.Event),
errors: make(chan error),
}
}
// NewEventWatcher returns an fs-event based file watcher
func NewEventWatcher() (FileWatcher, error) {
watcher, err := fsnotify.NewWatcher()
if err != nil {
return nil, err
}
return &fsNotifyWatcher{watcher}, nil
}