concurrency.go

// Copyright 2020 Google LLC
//
// 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 util

type Limiter struct {
	tokens chan bool
	limit  int
}

func (l *Limiter) Go(f func()) {
	l.tokens <- true
	go func() {
		f()
		<-l.tokens
	}()
}

func (l *Limiter) Close() {
	for i := 0; i < l.limit; i++ {
		l.tokens <- true
	}
}

func NewLimiter(limit int) *Limiter {
	return &Limiter{
		tokens: make(chan bool, limit),
		limit:  limit,
	}
}