mirror of
https://github.com/golang/go
synced 2024-11-26 17:07:09 -07:00
52 lines
997 B
Go
52 lines
997 B
Go
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// run
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// Copyright 2021 The Go Authors. 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 main
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import (
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"reflect"
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"runtime"
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"unsafe"
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)
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func k(c chan string, val string) string {
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b := make([]byte, 1000)
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runtime.SetFinalizer(&b[0], func(*byte) {
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c <- val
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})
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var s string
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h := (*reflect.StringHeader)(unsafe.Pointer(&s))
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h.Data = uintptr(unsafe.Pointer(&b[0]))
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h.Len = len(b)
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return s
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}
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func main() {
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{
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c := make(chan string, 2)
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m := make(map[string]int)
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m[k(c, "first")] = 0
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m[k(c, "second")] = 0
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runtime.GC()
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if s := <-c; s != "first" {
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panic("map[string], second key did not retain.")
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}
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runtime.KeepAlive(m)
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}
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{
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c := make(chan string, 2)
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m := make(map[[2]string]int)
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m[[2]string{k(c, "first")}] = 0
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m[[2]string{k(c, "second")}] = 0
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runtime.GC()
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if s := <-c; s != "first" {
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panic("map[[2]string], second key did not retain.")
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}
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runtime.KeepAlive(m)
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}
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}
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