The Tor Browser / file comparison
comparison: content/media/SharedBuffer.h
content/media/SharedBuffer.h
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
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| -1:000000000000 | 0:1f7635416a2f |
|---|---|
| 1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ | |
| 2 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 3 * License, v. 2.0. If a copy of the MPL was not distributed with this file, | |
| 4 * You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 5 | |
| 6 #ifndef MOZILLA_SHAREDBUFFER_H_ | |
| 7 #define MOZILLA_SHAREDBUFFER_H_ | |
| 8 | |
| 9 #include "mozilla/CheckedInt.h" | |
| 10 #include "mozilla/mozalloc.h" | |
| 11 #include "nsCOMPtr.h" | |
| 12 #include "nsAutoPtr.h" | |
| 13 | |
| 14 namespace mozilla { | |
| 15 | |
| 16 /** | |
| 17 * Base class for objects with a thread-safe refcount and a virtual | |
| 18 * destructor. | |
| 19 */ | |
| 20 class ThreadSharedObject { | |
| 21 public: | |
| 22 NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ThreadSharedObject) | |
| 23 | |
| 24 bool IsShared() { return mRefCnt.get() > 1; } | |
| 25 | |
| 26 virtual size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const | |
| 27 { | |
| 28 return 0; | |
| 29 } | |
| 30 | |
| 31 virtual size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const | |
| 32 { | |
| 33 return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf); | |
| 34 } | |
| 35 protected: | |
| 36 // Protected destructor, to discourage deletion outside of Release(): | |
| 37 virtual ~ThreadSharedObject() {} | |
| 38 }; | |
| 39 | |
| 40 /** | |
| 41 * Heap-allocated chunk of arbitrary data with threadsafe refcounting. | |
| 42 * Typically you would allocate one of these, fill it in, and then treat it as | |
| 43 * immutable while it's shared. | |
| 44 * This only guarantees 4-byte alignment of the data. For alignment we | |
| 45 * simply assume that the refcount is at least 4-byte aligned and its size | |
| 46 * is divisible by 4. | |
| 47 */ | |
| 48 class SharedBuffer : public ThreadSharedObject { | |
| 49 public: | |
| 50 void* Data() { return this + 1; } | |
| 51 | |
| 52 static already_AddRefed<SharedBuffer> Create(size_t aSize) | |
| 53 { | |
| 54 CheckedInt<size_t> size = sizeof(SharedBuffer); | |
| 55 size += aSize; | |
| 56 if (!size.isValid()) { | |
| 57 MOZ_CRASH(); | |
| 58 } | |
| 59 void* m = moz_xmalloc(size.value()); | |
| 60 nsRefPtr<SharedBuffer> p = new (m) SharedBuffer(); | |
| 61 NS_ASSERTION((reinterpret_cast<char*>(p.get() + 1) - reinterpret_cast<char*>(p.get())) % 4 == 0, | |
| 62 "SharedBuffers should be at least 4-byte aligned"); | |
| 63 return p.forget(); | |
| 64 } | |
| 65 | |
| 66 virtual size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const MOZ_OVERRIDE | |
| 67 { | |
| 68 return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf); | |
| 69 } | |
| 70 | |
| 71 private: | |
| 72 SharedBuffer() {} | |
| 73 }; | |
| 74 | |
| 75 } | |
| 76 | |
| 77 #endif /* MOZILLA_SHAREDBUFFER_H_ */ |
