tidb tokenlimiter 代码
文件路径：/server/tokenlimiter.go
/ Copyright 2015 PingCAP, Inc.
/
/ 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 server
/ Token is used as a permission to keep on running.
type Token struct {
}
/ TokenLimiter is used to limit the number of concurrent tasks.
type TokenLimiter struct {
count uint
ch chan *Token
}
/ Put releases the token.
func (tl *TokenLimiter) Put(tk *Token) {
tl.ch <- tk
}
/ Get obtains a token.
func (tl *TokenLimiter) Get() *Token {
return <-tl.ch
}
/ NewTokenLimiter creates a TokenLimiter with count tokens.
func NewTokenLimiter(count uint) *TokenLimiter {
tl := &TokenLimiter{count: count, ch: make(chan *Token, count)}
for i := uint(0); i < count; i++ {
tl.ch <- &Token{}
}
return tl
}