зеркало из https://github.com/mozilla/gecko-dev.git
81 строка
2.3 KiB
C++
81 строка
2.3 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
|
|
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
|
|
* You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
#ifndef MOZILLA_SHAREDBUFFER_H_
|
|
#define MOZILLA_SHAREDBUFFER_H_
|
|
|
|
#include "mozilla/CheckedInt.h"
|
|
#include "mozilla/mozalloc.h"
|
|
#include "nsCOMPtr.h"
|
|
|
|
namespace mozilla {
|
|
|
|
class AudioBlockBuffer;
|
|
|
|
/**
|
|
* Base class for objects with a thread-safe refcount and a virtual
|
|
* destructor.
|
|
*/
|
|
class ThreadSharedObject {
|
|
public:
|
|
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ThreadSharedObject)
|
|
|
|
bool IsShared() { return mRefCnt.get() > 1; }
|
|
|
|
virtual AudioBlockBuffer* AsAudioBlockBuffer() { return nullptr; };
|
|
|
|
virtual size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
virtual size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const
|
|
{
|
|
return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
|
|
}
|
|
protected:
|
|
// Protected destructor, to discourage deletion outside of Release():
|
|
virtual ~ThreadSharedObject() {}
|
|
};
|
|
|
|
/**
|
|
* Heap-allocated chunk of arbitrary data with threadsafe refcounting.
|
|
* Typically you would allocate one of these, fill it in, and then treat it as
|
|
* immutable while it's shared.
|
|
* This only guarantees 4-byte alignment of the data. For alignment we simply
|
|
* assume that the memory from malloc is at least 4-byte aligned and the
|
|
* refcount's size is large enough that SharedBuffer's size is divisible by 4.
|
|
*/
|
|
class SharedBuffer : public ThreadSharedObject {
|
|
public:
|
|
void* Data() { return this + 1; }
|
|
|
|
static already_AddRefed<SharedBuffer> Create(size_t aSize)
|
|
{
|
|
CheckedInt<size_t> size = sizeof(SharedBuffer);
|
|
size += aSize;
|
|
if (!size.isValid()) {
|
|
MOZ_CRASH();
|
|
}
|
|
void* m = moz_xmalloc(size.value());
|
|
RefPtr<SharedBuffer> p = new (m) SharedBuffer();
|
|
NS_ASSERTION((reinterpret_cast<char*>(p.get() + 1) - reinterpret_cast<char*>(p.get())) % 4 == 0,
|
|
"SharedBuffers should be at least 4-byte aligned");
|
|
return p.forget();
|
|
}
|
|
|
|
size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const override
|
|
{
|
|
return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
|
|
}
|
|
|
|
private:
|
|
SharedBuffer() {}
|
|
};
|
|
|
|
} // namespace mozilla
|
|
|
|
#endif /* MOZILLA_SHAREDBUFFER_H_ */
|