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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/wtf/ThreadSafeShared.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/wtf/ThreadSafeShared.h')
-rw-r--r-- | Source/JavaScriptCore/wtf/ThreadSafeShared.h | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/Source/JavaScriptCore/wtf/ThreadSafeShared.h b/Source/JavaScriptCore/wtf/ThreadSafeShared.h new file mode 100644 index 0000000..33c6612 --- /dev/null +++ b/Source/JavaScriptCore/wtf/ThreadSafeShared.h @@ -0,0 +1,148 @@ +/* + * Copyright (C) 2007, 2008, 2010 Apple Inc. All rights reserved. + * Copyright (C) 2007 Justin Haygood (jhaygood@reaktix.com) + * + * 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. + * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of + * its contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY APPLE 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 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. + * + * + * Note: The implementations of InterlockedIncrement and InterlockedDecrement are based + * on atomic_increment and atomic_exchange_and_add from the Boost C++ Library. The license + * is virtually identical to the Apple license above but is included here for completeness. + * + * Boost Software License - Version 1.0 - August 17th, 2003 + * + * Permission is hereby granted, free of charge, to any person or organization + * obtaining a copy of the software and accompanying documentation covered by + * this license (the "Software") to use, reproduce, display, distribute, + * execute, and transmit the Software, and to prepare derivative works of the + * Software, and to permit third-parties to whom the Software is furnished to + * do so, all subject to the following: + * + * The copyright notices in the Software and this entire statement, including + * the above license grant, this restriction and the following disclaimer, + * must be included in all copies of the Software, in whole or in part, and + * all derivative works of the Software, unless such copies or derivative + * works are solely in the form of machine-executable object code generated by + * a source language processor. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT + * SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE + * FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + * DEALINGS IN THE SOFTWARE. + */ + +#ifndef ThreadSafeShared_h +#define ThreadSafeShared_h + +#include "Platform.h" + +#include <wtf/Atomics.h> +#include <wtf/Noncopyable.h> +#include <wtf/ThreadingPrimitives.h> + +namespace WTF { + +class ThreadSafeSharedBase : public Noncopyable { +public: + ThreadSafeSharedBase(int initialRefCount = 1) + : m_refCount(initialRefCount) + { + } + + void ref() + { +#if USE(LOCKFREE_THREADSAFESHARED) + atomicIncrement(&m_refCount); +#else + MutexLocker locker(m_mutex); + ++m_refCount; +#endif + } + + bool hasOneRef() + { + return refCount() == 1; + } + + int refCount() const + { +#if !USE(LOCKFREE_THREADSAFESHARED) + MutexLocker locker(m_mutex); +#endif + return static_cast<int const volatile &>(m_refCount); + } + +protected: + // Returns whether the pointer should be freed or not. + bool derefBase() + { +#if USE(LOCKFREE_THREADSAFESHARED) + if (atomicDecrement(&m_refCount) <= 0) + return true; +#else + int refCount; + { + MutexLocker locker(m_mutex); + --m_refCount; + refCount = m_refCount; + } + if (refCount <= 0) + return true; +#endif + return false; + } + +private: + template<class T> + friend class CrossThreadRefCounted; + + int m_refCount; +#if !USE(LOCKFREE_THREADSAFESHARED) + mutable Mutex m_mutex; +#endif +}; + +template<class T> class ThreadSafeShared : public ThreadSafeSharedBase { +public: + void deref() + { + if (derefBase()) + delete static_cast<T*>(this); + } + +protected: + ThreadSafeShared() + { + } +}; + +} // namespace WTF + +using WTF::ThreadSafeShared; + +#endif // ThreadSafeShared_h |