etcd/storage/watcher.go

package storage

import (
	"sync"

	"github.com/coreos/etcd/storage/storagepb"
)

type watcher struct {
	key    []byte
	prefix bool
	cur    int64
	end    int64

	ch  chan storagepb.Event
	mu  sync.Mutex
	err error
}

func newWatcher(key []byte, prefix bool, start, end int64) *watcher {
	return &watcher{
		key:    key,
		prefix: prefix,
		cur:    start,
		end:    end,
		ch:     make(chan storagepb.Event, 10),
	}
}

func (w *watcher) Event() <-chan storagepb.Event { return w.ch }

func (w *watcher) Err() error {
	w.mu.Lock()
	defer w.mu.Unlock()
	return w.err
}

func (w *watcher) stopWithError(err error) {
	if w.err != nil {
		return
	}
	close(w.ch)
	w.mu.Lock()
	w.err = err
	w.mu.Unlock()
}