mirror of https://github.com/ceph/go-ceph
38 lines
868 B
Go
38 lines
868 B
Go
//go:build !go1.21
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// +build !go1.21
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// This code assumes a non-moving garbage collector, which is the case until at
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// least go 1.20
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package cutil
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import (
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"unsafe"
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)
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// PtrGuard respresents a guarded Go pointer (pointing to memory allocated by Go
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// runtime) stored in C memory (allocated by C)
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type PtrGuard struct {
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cPtr CPtr
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goPtr unsafe.Pointer
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}
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// NewPtrGuard writes the goPtr (pointing to Go memory) into C memory at the
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// position cPtr, and returns a PtrGuard object.
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func NewPtrGuard(cPtr CPtr, goPtr unsafe.Pointer) *PtrGuard {
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var v PtrGuard
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v.cPtr = cPtr
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v.goPtr = goPtr
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p := (*unsafe.Pointer)(unsafe.Pointer(cPtr))
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*p = goPtr
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return &v
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}
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// Release removes the guarded Go pointer from the C memory by overwriting it
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// with NULL.
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func (v *PtrGuard) Release() {
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p := (*unsafe.Pointer)(unsafe.Pointer(v.cPtr))
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*p = nil
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v.goPtr = nil
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}
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