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author | Steve Block <steveblock@google.com> | 2011-05-13 06:44:40 -0700 |
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committer | Android (Google) Code Review <android-gerrit@google.com> | 2011-05-13 06:44:40 -0700 |
commit | 08014c20784f3db5df3a89b73cce46037b77eb59 (patch) | |
tree | 47749210d31e19e6e2f64036fa8fae2ad693476f /Source/JavaScriptCore/runtime/GCHandle.h | |
parent | 860220379e56aeb66424861ad602b07ee22b4055 (diff) | |
parent | 4c3661f7918f8b3f139f824efb7855bedccb4c94 (diff) | |
download | external_webkit-08014c20784f3db5df3a89b73cce46037b77eb59.zip external_webkit-08014c20784f3db5df3a89b73cce46037b77eb59.tar.gz external_webkit-08014c20784f3db5df3a89b73cce46037b77eb59.tar.bz2 |
Merge changes Ide388898,Ic49f367c,I1158a808,Iacb6ca5d,I2100dd3a,I5c1abe54,Ib0ef9902,I31dbc523,I570314b3
* changes:
Merge WebKit at r75315: Update WebKit version
Merge WebKit at r75315: Add FrameLoaderClient PageCache stubs
Merge WebKit at r75315: Stub out AXObjectCache::remove()
Merge WebKit at r75315: Fix ImageBuffer
Merge WebKit at r75315: Fix PluginData::initPlugins()
Merge WebKit at r75315: Fix conflicts
Merge WebKit at r75315: Fix Makefiles
Merge WebKit at r75315: Move Android-specific WebCore files to Source
Merge WebKit at r75315: Initial merge by git.
Diffstat (limited to 'Source/JavaScriptCore/runtime/GCHandle.h')
-rw-r--r-- | Source/JavaScriptCore/runtime/GCHandle.h | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/Source/JavaScriptCore/runtime/GCHandle.h b/Source/JavaScriptCore/runtime/GCHandle.h new file mode 100644 index 0000000..8818f79 --- /dev/null +++ b/Source/JavaScriptCore/runtime/GCHandle.h @@ -0,0 +1,116 @@ +/* + * Copyright (C) 2010 Apple Inc. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, + * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS + * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF + * THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef GCHandle_h +#define GCHandle_h + +#include <wtf/Assertions.h> + +namespace JSC { + +class Heap; +class JSCell; +class WeakGCHandle; +class WeakGCHandlePool; + +class WeakGCHandle { + friend class WeakGCHandlePool; + +public: + // Because JSCell objects are aligned, we can use the lower two bits as + // status flags. The least significant bit is set when the handle is not a + // pointer, i.e. when it's used as a offset for the free list in + // WeakGCHandlePool. The second least significant bit is set when the object + // the pointer corresponds to has been deleted by a garbage collection + + bool isValidPtr() { return !(m_ptr & 3); } + bool isPtr() { return !(m_ptr & 1); } + bool isNext() { return (m_ptr & 3) == 1; } + + void invalidate() + { + ASSERT(isValidPtr()); + m_ptr |= 2; + } + + JSCell* get() + { + ASSERT(isPtr()); + return reinterpret_cast<JSCell*>(m_ptr & ~3); + } + + void set(JSCell* p) + { + m_ptr = reinterpret_cast<uintptr_t>(p); + ASSERT(isPtr()); + } + + WeakGCHandlePool* pool(); + +private: + uintptr_t getNextInFreeList() + { + ASSERT(isNext()); + return m_ptr >> 2; + } + + void setNextInFreeList(uintptr_t n) + { + m_ptr = (n << 2) | 1; + ASSERT(isNext()); + } + + uintptr_t m_ptr; +}; + +class WeakGCHandlePool { +public: + static const size_t poolSize = 32 * 1024; // 32k + static const size_t poolMask = ~(poolSize - 1); + static const size_t numPoolEntries = (poolSize - sizeof(Heap*) - 3 * sizeof(unsigned)) / sizeof(WeakGCHandle); + + WeakGCHandlePool(); + + WeakGCHandle* allocate(JSCell* cell); + void free(WeakGCHandle*); + + bool isFull() + { + ASSERT(m_entriesSize < WeakGCHandlePool::numPoolEntries); + return m_entriesSize == WeakGCHandlePool::numPoolEntries - 1; + } + + void update(); + +private: + Heap* m_heap; + unsigned m_entriesSize; + unsigned m_initialAlloc; + + WeakGCHandle m_entries[WeakGCHandlePool::numPoolEntries]; +}; + +} +#endif |