57 lines
877 B
Go
57 lines
877 B
Go
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// Copyright 2013, Google Inc. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package sync2
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import (
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"sync"
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)
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// Cond is an alternate implementation of sync.Cond
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type Cond struct {
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L sync.Locker
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sema chan struct{}
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waiters AtomicInt64
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}
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func NewCond(l sync.Locker) *Cond {
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return &Cond{L: l, sema: make(chan struct{})}
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}
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func (c *Cond) Wait() {
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c.waiters.Add(1)
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c.L.Unlock()
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<-c.sema
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c.L.Lock()
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}
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func (c *Cond) Signal() {
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for {
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w := c.waiters.Get()
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if w == 0 {
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return
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}
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if c.waiters.CompareAndSwap(w, w-1) {
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break
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}
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}
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c.sema <- struct{}{}
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}
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func (c *Cond) Broadcast() {
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var w int64
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for {
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w = c.waiters.Get()
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if w == 0 {
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return
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}
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if c.waiters.CompareAndSwap(w, 0) {
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break
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}
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}
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for i := int64(0); i < w; i++ {
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c.sema <- struct{}{}
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}
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}
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