Move webaudio to oilpan

Source/heap/Heap.h

 /*
  * Copyright (C) 2013 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 21 matching lines @@
 #define Heap_h
 
 #include "heap/AddressSanitizer.h"
 #include "heap/HeapExport.h"
 #include "heap/ThreadState.h"
 #include "heap/Visitor.h"
 
 #include "wtf/Assertions.h"
 #include "wtf/OwnPtr.h"
 #include "wtf/PassRefPtr.h"
+#include "wtf/ThreadSafeRefCounted.h"
 
 #include <stdint.h>
 
 namespace WebCore {
 
 const size_t blinkPageSizeLog2 = 17;
 const size_t blinkPageSize = 1 << blinkPageSizeLog2;
 const size_t blinkPageOffsetMask = blinkPageSize - 1;
 const size_t blinkPageBaseMask = ~blinkPageOffsetMask;
 // Double precision floats are more efficient when 8 byte aligned, so we 8 byte
 // align all allocations even on 32 bit.
 const size_t allocationGranularity = 8;
 const size_t allocationMask = allocationGranularity - 1;
 const size_t objectStartBitMapSize = (blinkPageSize + ((8 * allocationGranularity) - 1)) / (8 * allocationGranularity);
 const size_t reservedForObjectBitMap = ((objectStartBitMapSize + allocationMask) & ~allocationMask);
 const size_t maxHeapObjectSize = 1 << 27;
 
 const size_t markBitMask = 1;
 const size_t freeListMask = 2;
 const size_t debugBitMask = 4;
 const size_t sizeMask = ~7;
 const uint8_t freelistZapValue = 42;
 const uint8_t finalizedZapValue = 24;
 
 class HeapStats;
 class PageMemory;
 template<ThreadAffinity affinity> class ThreadLocalPersistents;
 template<typename T, typename RootsAccessor = ThreadLocalPersistents<ThreadingTrait<T>::Affinity > > class Persistent;
+template<typename T> class CrossThreadPersistent;
 
 HEAP_EXPORT size_t osPageSize();
 
 // Blink heap pages are set up with a guard page before and after the
 // payload.
 inline size_t blinkPagePayloadSize()
 {
     return blinkPageSize - 2 * osPageSize();
 }
 
@@ skipping 448 matching lines @@
     static const int numberOfEntriesLog2 = 12;
     static const int numberOfEntries = 1 << numberOfEntriesLog2;
 
     static size_t hash(Address);
 
     WTF::OwnPtr<HeapContainsCache::Entry[]> m_entries;
 
     friend class ThreadState;
 };
 
+// FIXME(oilpan): The current implementation requires the deallocating
+// thread to be the same as the thread on which this instance was first
+// allocated. Only the refs/derefs that are not 0 -> 1 or 1 -> 0 are
+// thread safe.
+// This is currently used by the WebAudio code.
+// We should attempt to restructure the WebAudio code so that the main thread
+// alone determines life-time and receives messages about life-time from the
+// audio thread.
+template<typename T>
+class ThreadSafeRefCountedGarbageCollected : public GarbageCollectedFinalized<T>, public WTF::ThreadSafeRefCountedBase {
+    WTF_MAKE_NONCOPYABLE(ThreadSafeRefCountedGarbageCollected);
+
+public:
+    ThreadSafeRefCountedGarbageCollected()
+    {
+#ifndef NDEBUG
+        m_threadState = ThreadState::current();
+#endif
+        m_keepAlive = adoptPtr(new CrossThreadPersistent<T>(static_cast<T*>(this)));
+    }
+
+    // Override ref to deal with a case where a reference count goes up
+    // from 0 to 1. This can happen in the following scenario:
+    // (1) The reference count becomes 0, but on-stack pointers keep references to the object.
+    // (2) The on-stack pointer is assigned to a RefPtr. The reference count becomes 1.
+    // In this case, we have to resurrect m_keepAlive.
+    void ref()
+    {
+        MutexLocker lock(m_mutex);
+        if (UNLIKELY(!refCount())) {
+            ASSERT(!m_keepAlive);
+            ASSERT(m_threadState->contains(reinterpret_cast<Address>(this)));
+            // ASSERT(m_threadState == ThreadState::current());
+            m_keepAlive = adoptPtr(new CrossThreadPersistent<T>(static_cast<T*>(this)));
+        }
+        WTF::ThreadSafeRefCountedBase::ref();
+    }
+
+    // Override deref to deal with our own deallocation based on ref counting.
+    void deref()
+    {
+        MutexLocker lock(m_mutex);
+        if (derefBase()) {
+            ASSERT(m_threadState == ThreadState::current());
+            m_keepAlive.clear();
+        }
+    }
+
+    using GarbageCollectedFinalized<T>::operator new;
+    using GarbageCollectedFinalized<T>::operator delete;
+
+protected:
+    ~ThreadSafeRefCountedGarbageCollected() { }
+
+private:
+    OwnPtr<CrossThreadPersistent<T> > m_keepAlive;
+    mutable Mutex m_mutex;
+#ifndef NDEBUG
+    ThreadState* m_threadState;
+#endif
+};
+
 // The CallbackStack contains all the visitor callbacks used to trace and mark
 // objects. A specific CallbackStack instance contains at most bufferSize elements.
 // If more space is needed a new CallbackStack instance is created and chained
 // together with the former instance. I.e. a logical CallbackStack can be made of
 // multiple chained CallbackStack object instances.
 // There are two logical callback stacks. One containing all the marking callbacks and
 // one containing the weak pointer callbacks.
 class CallbackStack {
 public:
     CallbackStack(CallbackStack** first)
@@ skipping 1209 matching lines @@
 // to export. This forces it to export all the methods from ThreadHeap.
 template<> void ThreadHeap<FinalizedHeapObjectHeader>::addPageToHeap(const GCInfo*);
 template<> void ThreadHeap<HeapObjectHeader>::addPageToHeap(const GCInfo*);
 extern template class HEAP_EXPORT ThreadHeap<FinalizedHeapObjectHeader>;
 extern template class HEAP_EXPORT ThreadHeap<HeapObjectHeader>;
 #endif
 
 }
 
 #endif // Heap_h