两把互斥锁实现waitGroup功能

package main

import (
    "log"
    "sync"
)

type Counter struct {
    count     int
    mu1       sync.Mutex
    mu2       sync.Mutex
    needLock2 bool
}

func NewCounter(initValue int) *Counter {
    c := &Counter{count: initValue}
    if initValue != 0 {
        c.mu2.Lock()
    }
    return c
}

func (counter *Counter) Add(v int) {
    if v == 0 {
        return
    }
    counter.mu1.Lock()
    counter.count += v
    if counter.count != 0 && counter.needLock2 {
        counter.mu2.Lock()
        counter.needLock2 = false
    } else if counter.count == 0 {
        counter.mu2.Unlock()
        counter.needLock2 = true
    }
    log.Println("current value:", counter.count)
    counter.mu1.Unlock()
}

func (counter *Counter) Wait() {
    counter.mu2.Lock()
    counter.mu2.Unlock()
    log.Println("wait成功")
}

func main() {
    //counter := NewCounter(200)
    //wg := sync.WaitGroup{}
    for i := 0; i < 100; i++ {
        go func() {}()
    }
}