diff --git a/watcher/batcher.go b/watcher/batcher.go new file mode 100644 index 000000000..12c51940d --- /dev/null +++ b/watcher/batcher.go @@ -0,0 +1,73 @@ +// Copyright 2020 The Hugo Authors. All rights reserved. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package watcher + +import ( + "time" + + "github.com/fsnotify/fsnotify" +) + +// Batcher batches file watch events in a given interval. +type Batcher struct { + *fsnotify.Watcher + interval time.Duration + done chan struct{} + + Events chan []fsnotify.Event // Events are returned on this channel +} + +// New creates and starts a Batcher with the given time interval. +func New(interval time.Duration) (*Batcher, error) { + watcher, err := fsnotify.NewWatcher() + + batcher := &Batcher{} + batcher.Watcher = watcher + batcher.interval = interval + batcher.done = make(chan struct{}, 1) + batcher.Events = make(chan []fsnotify.Event, 1) + + if err == nil { + go batcher.run() + } + + return batcher, err +} + +func (b *Batcher) run() { + tick := time.Tick(b.interval) + evs := make([]fsnotify.Event, 0) +OuterLoop: + for { + select { + case ev := <-b.Watcher.Events: + evs = append(evs, ev) + case <-tick: + if len(evs) == 0 { + continue + } + b.Events <- evs + evs = make([]fsnotify.Event, 0) + case <-b.done: + break OuterLoop + } + } + close(b.done) +} + +// Close stops the watching of the files. +func (b *Batcher) Close() { + b.done <- struct{}{} + b.Watcher.Close() +}