Golang中实现禁止拷贝noCopy

Go中没有原生的禁止拷贝的方式，所以如果有的结构体，你希望使用者无法拷贝，只能指针传递保证全局唯一的话，可以这么干，定义 一个结构体叫 noCopy ，要实现 sync.Locker 这个接口

// noCopy may be embedded into structs which must not be copied
// after the first use.
//
// See https://golang.org/issues/8005#issuecomment-190753527
// for details.
type noCopy struct{}

// Lock is a no-op used by -copylocks checker from `go vet`.
func (*noCopy) Lock() {}
func (*noCopy) UnLock() {}

然后把 noCopy 嵌到你自定义的结构体里，然后 go vet 就可以帮我们进行检查了。举个例子：

package main

import (
    "fmt"
)

type noCopy struct{}

func (*noCopy) Lock()   {}
func (*noCopy) Unlock() {}

type Demo struct {
    noCopy noCopy
}

func Copy(d Demo) {
    CopyTwice(d)
}
func CopyTwice(d Demo) {}

func main() {
    d := Demo{}
    fmt.Printf("%+v", d)

    Copy(d)

    fmt.Printf("%+v", d)
}

执行一下：

$ go vet main.go
# command-line-arguments
./main.go:16: Copy passes lock by value: main.Demo contains main.noCopy
./main.go:17: call of CopyTwice copies lock value: main.Demo contains main.noCopy
./main.go:19: CopyTwice passes lock by value: main.Demo contains main.noCopy
./main.go:23: call of fmt.Printf copies lock value: main.Demo contains main.noCopy
./main.go:25: call of Copy copies lock value: main.Demo contains main.noCopy
./main.go:27: call of fmt.Printf copies lock value: main.Demo contains main.noCopy