Go語(yǔ)言讀寫(xiě)鎖如何設(shè)置超時(shí)

在Go語(yǔ)言中，沒(méi)有內(nèi)置的讀寫(xiě)鎖支持超時(shí)功能。但是，你可以使用time.After函數(shù)和select語(yǔ)句來(lái)實(shí)現(xiàn)一個(gè)帶有超時(shí)的讀寫(xiě)鎖。下面是一個(gè)簡(jiǎn)單的示例：

package main

import (
	"fmt"
	"sync"
	"time"
)

type TimeoutReadWriteLock struct {
	mu        sync.RWMutex
	cond      *sync.Cond
	timeout   time.Duration
}

func NewTimeoutReadWriteLock(timeout time.Duration) *TimeoutReadWriteLock {
	return &TimeoutReadWriteLock{
		cond: sync.NewCond(&sync.Mutex{}),
		timeout: timeout,
	}
}

func (l *TimeoutReadWriteLock) ReadLock() {
	l.mu.RLock()
	defer l.mu.RUnlock()

	select {
	case <-time.After(l.timeout):
		return fmt.Errorf("read lock timeout")
	default:
		return nil
	}
}

func (l *TimeoutReadWriteLock) ReadUnlock() {
	l.mu.RUnlock()
}

func (l *TimeoutReadWriteLock) WriteLock() {
	l.mu.Lock()
	defer l.mu.Unlock()

	select {
	case <-time.After(l.timeout):
		return fmt.Errorf("write lock timeout")
	default:
		return nil
	}
}

func (l *TimeoutReadWriteLock) WriteUnlock() {
	l.mu.Unlock()
}

func main() {
	lock := NewTimeoutReadWriteLock(2 * time.Second)

	go func() {
		time.Sleep(1 * time.Second)
		lock.WriteLock()
		fmt.Println("Write lock acquired")
		time.Sleep(3 * time.Second)
		lock.WriteUnlock()
		fmt.Println("Write lock released")
	}()

	go func() {
		time.Sleep(500 * time.Millisecond)
		err := lock.ReadLock()
		if err != nil {
			fmt.Println("Read lock error:", err)
		} else {
			fmt.Println("Read lock acquired")
			time.Sleep(2 * time.Second)
			lock.ReadUnlock()
			fmt.Println("Read lock released")
		}
	}()

	time.Sleep(10 * time.Second)
}

在這個(gè)示例中，我們創(chuàng)建了一個(gè)TimeoutReadWriteLock結(jié)構(gòu)體，它包含一個(gè)讀寫(xiě)鎖、一個(gè)條件變量和一個(gè)超時(shí)時(shí)間。ReadLock和WriteLock方法使用select語(yǔ)句來(lái)檢查是否已經(jīng)超過(guò)了超時(shí)時(shí)間。如果超過(guò)了超時(shí)時(shí)間，它們將返回一個(gè)錯(cuò)誤；否則，它們將繼續(xù)執(zhí)行讀寫(xiě)鎖操作。