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https://github.com/ceph/go-ceph
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430dea5b7f
In order to be able to swich on and off PtrGuard usage, SyncBuffer implements a typical usage pattern of PtrGuard, that is a data buffer referenced from inside a C allocated struct, in two ways: 1) using a PtrGuard to dierctly store a pointer to the Go buffer in C memory, or 2) allocating a C buffer of same size and syncing data back with C.memcpy(). The implementation can be chosen with the with_ptrguard build tag. Signed-off-by: Sven Anderson <sven@redhat.com>
38 lines
758 B
Go
38 lines
758 B
Go
// +build !ptrguard
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package cutil
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// SyncBuffer is a C buffer connected to a data slice
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type SyncBuffer struct {
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data []byte
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cPtr *CPtr
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}
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// NewSyncBuffer creates a C buffer from a data slice and stores it at CPtr
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func NewSyncBuffer(cPtr CPtr, data []byte) *SyncBuffer {
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var v SyncBuffer
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v.data = data
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v.cPtr = (*CPtr)(cPtr)
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*v.cPtr = CBytes(data)
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return &v
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}
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// Release releases the C buffer and nulls its stored pointer
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func (v *SyncBuffer) Release() {
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if v.cPtr != nil {
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Free(*v.cPtr)
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*v.cPtr = nil
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v.cPtr = nil
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}
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v.data = nil
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}
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// Sync asserts that changes in the C buffer are available in the data
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// slice
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func (v *SyncBuffer) Sync() {
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if v.cPtr == nil {
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return
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}
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Memcpy(CPtr(&v.data[0]), CPtr(*v.cPtr), SizeT(len(v.data)))
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}
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