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/*
* Copyright (C) 2007, 2008, 2010, 2013, 2014 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.
*
* 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.
*/
#pragma once
#include <atomic>
#include <wtf/FastMalloc.h>
#include <wtf/MainThread.h>
#include <wtf/Noncopyable.h>
#include <wtf/RefCounted.h>
#include <wtf/SwiftBridging.h>
namespace WTF {
class WTF_EMPTY_BASE_CLASS ThreadSafeRefCountedBase {
WTF_MAKE_NONCOPYABLE(ThreadSafeRefCountedBase);
WTF_DEPRECATED_MAKE_FAST_ALLOCATED(ThreadSafeRefCountedBase);
public:
void ref() const
{
m_refCountDebugger.willRef(m_refCount, RefCountIsThreadSafe::Yes);
++m_refCount;
}
bool hasOneRef() const { return m_refCount == 1; }
uint32_t refCount() const { return m_refCount; }
// Debug APIs
void adopted() { m_refCountDebugger.adopted(); }
void relaxAdoptionRequirement() { m_refCountDebugger.relaxAdoptionRequirement(); }
void disableThreadingChecks() { m_refCountDebugger.disableThreadingChecks(); }
RefCountDebugger& refCountDebugger() { return m_refCountDebugger; }
protected:
ThreadSafeRefCountedBase()
{
// FIXME: Lots of subclasses violate our adoption requirements. Migrate
// this call into only those subclasses that need it.
m_refCountDebugger.relaxAdoptionRequirement();
}
~ThreadSafeRefCountedBase()
{
m_refCountDebugger.willDestroy(m_refCount);
// FIXME: Test performance, then change this to RELEASE_ASSERT.
ASSERT(m_refCount == 1);
}
// Returns true if the pointer should be freed.
bool derefBase() const
{
m_refCountDebugger.willDeref(m_refCount, RefCountIsThreadSafe::Yes);
if (!--m_refCount) [[unlikely]] {
m_refCountDebugger.willDelete();
m_refCount = 1;
return true;
}
return false;
}
private:
mutable std::atomic<uint32_t> m_refCount { 1 };
NO_UNIQUE_ADDRESS RefCountDebugger m_refCountDebugger;
};
template<class T, DestructionThread destructionThread = DestructionThread::Any> class ThreadSafeRefCounted : public ThreadSafeRefCountedBase {
public:
void deref() const
{
if (!derefBase())
return;
if constexpr (destructionThread == DestructionThread::Any) {
delete static_cast<const T*>(this);
} else if constexpr (destructionThread == DestructionThread::Main) {
SUPPRESS_UNCOUNTED_LAMBDA_CAPTURE ensureOnMainThread([this] {
delete static_cast<const T*>(this);
});
} else if constexpr (destructionThread == DestructionThread::MainRunLoop) {
SUPPRESS_UNCOUNTED_LAMBDA_CAPTURE ensureOnMainRunLoop([this] {
delete static_cast<const T*>(this);
});
} else
STATIC_ASSERT_NOT_REACHED_FOR_VALUE(destructionThread, "Unexpected destructionThread enumerator value");
}
protected:
ThreadSafeRefCounted() = default;
~ThreadSafeRefCounted() = default;
} SWIFT_RETURNED_AS_UNRETAINED_BY_DEFAULT;
inline void adopted(ThreadSafeRefCountedBase* object)
{
if (!object)
return;
object->adopted();
}
} // namespace WTF
using WTF::ThreadSafeRefCounted;
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