JavaScriptCore-1097.3.tar.gz

[apple/javascriptcore.git] / heap / WeakBlock.cpp

diff --git a/heap/WeakBlock.cpp b/heap/WeakBlock.cpp
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+/*
+ * Copyright (C) 2012 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.
+ */
+
+#include "config.h"
+#include "WeakBlock.h"
+
+#include "Heap.h"
+#include "HeapRootVisitor.h"
+#include "JSObject.h"
+#include "ScopeChain.h"
+#include "Structure.h"
+
+namespace JSC {
+
+WeakBlock* WeakBlock::create()
+{
+    PageAllocation allocation = PageAllocation::allocate(blockSize, OSAllocator::JSGCHeapPages);
+    if (!static_cast<bool>(allocation))
+        CRASH();
+    return new (NotNull, allocation.base()) WeakBlock(allocation);
+}
+
+void WeakBlock::destroy(WeakBlock* block)
+{
+    block->m_allocation.deallocate();
+}
+
+WeakBlock::WeakBlock(PageAllocation& allocation)
+    : m_allocation(allocation)
+{
+    for (size_t i = 0; i < weakImplCount(); ++i) {
+        WeakImpl* weakImpl = &weakImpls()[i];
+        new (NotNull, weakImpl) WeakImpl;
+        addToFreeList(&m_sweepResult.freeList, weakImpl);
+    }
+
+    ASSERT(!m_sweepResult.isNull() && m_sweepResult.blockIsFree);
+}
+
+void WeakBlock::finalizeAll()
+{
+    for (size_t i = 0; i < weakImplCount(); ++i) {
+        WeakImpl* weakImpl = &weakImpls()[i];
+        if (weakImpl->state() >= WeakImpl::Finalized)
+            continue;
+        weakImpl->setState(WeakImpl::Dead);
+        finalize(weakImpl);
+    }
+}
+
+void WeakBlock::sweep()
+{
+    if (!m_sweepResult.isNull())
+        return;
+
+    SweepResult sweepResult;
+    for (size_t i = 0; i < weakImplCount(); ++i) {
+        WeakImpl* weakImpl = &weakImpls()[i];
+        if (weakImpl->state() == WeakImpl::Dead)
+            finalize(weakImpl);
+        if (weakImpl->state() == WeakImpl::Deallocated)
+            addToFreeList(&sweepResult.freeList, weakImpl);
+        else
+            sweepResult.blockIsFree = false;
+    }
+
+    m_sweepResult = sweepResult;
+    ASSERT(!m_sweepResult.isNull());
+}
+
+void WeakBlock::visitLiveWeakImpls(HeapRootVisitor& heapRootVisitor)
+{
+    // If a block is completely empty, a visit won't have any effect.
+    if (!m_sweepResult.isNull() && m_sweepResult.blockIsFree)
+        return;
+
+    SlotVisitor& visitor = heapRootVisitor.visitor();
+
+    for (size_t i = 0; i < weakImplCount(); ++i) {
+        WeakImpl* weakImpl = &weakImpls()[i];
+        if (weakImpl->state() != WeakImpl::Live)
+            continue;
+
+        const JSValue& jsValue = weakImpl->jsValue();
+        if (Heap::isMarked(jsValue.asCell()))
+            continue;
+
+        WeakHandleOwner* weakHandleOwner = weakImpl->weakHandleOwner();
+        if (!weakHandleOwner)
+            continue;
+
+        if (!weakHandleOwner->isReachableFromOpaqueRoots(Handle<Unknown>::wrapSlot(&const_cast<JSValue&>(jsValue)), weakImpl->context(), visitor))
+            continue;
+
+        heapRootVisitor.visit(&const_cast<JSValue&>(jsValue));
+    }
+}
+
+void WeakBlock::visitDeadWeakImpls(HeapRootVisitor&)
+{
+    // If a block is completely empty, a visit won't have any effect.
+    if (!m_sweepResult.isNull() && m_sweepResult.blockIsFree)
+        return;
+
+    for (size_t i = 0; i < weakImplCount(); ++i) {
+        WeakImpl* weakImpl = &weakImpls()[i];
+        if (weakImpl->state() > WeakImpl::Dead)
+            continue;
+
+        if (Heap::isMarked(weakImpl->jsValue().asCell())) {
+            ASSERT(weakImpl->state() == WeakImpl::Live);
+            continue;
+        }
+
+        weakImpl->setState(WeakImpl::Dead);
+    }
+}
+
+} // namespace JSC