JavaScriptCore-903.tar.gz

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

diff --git a/heap/HandleHeap.cpp b/heap/HandleHeap.cpp
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+++ b/heap/HandleHeap.cpp
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+/*
+ * Copyright (C) 2011 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 "HandleHeap.h"
+
+#include "JSObject.h"
+
+namespace JSC {
+
+WeakHandleOwner::~WeakHandleOwner()
+{
+}
+
+bool WeakHandleOwner::isReachableFromOpaqueRoots(Handle<Unknown>, void*, SlotVisitor&)
+{
+    return false;
+}
+
+void WeakHandleOwner::finalize(Handle<Unknown>, void*)
+{
+}
+
+HandleHeap::HandleHeap(JSGlobalData* globalData)
+    : m_globalData(globalData)
+    , m_nextToFinalize(0)
+{
+    grow();
+}
+
+void HandleHeap::grow()
+{
+    Node* block = m_blockStack.grow();
+    for (int i = m_blockStack.blockLength - 1; i >= 0; --i) {
+        Node* node = &block[i];
+        new (node) Node(this);
+        m_freeList.push(node);
+    }
+}
+
+void HandleHeap::markStrongHandles(HeapRootVisitor& heapRootMarker)
+{
+    Node* end = m_strongList.end();
+    for (Node* node = m_strongList.begin(); node != end; node = node->next())
+        heapRootMarker.mark(node->slot());
+}
+
+void HandleHeap::markWeakHandles(HeapRootVisitor& heapRootVisitor)
+{
+    SlotVisitor& visitor = heapRootVisitor.visitor();
+
+    Node* end = m_weakList.end();
+    for (Node* node = m_weakList.begin(); node != end; node = node->next()) {
+        ASSERT(isValidWeakNode(node));
+        JSCell* cell = node->slot()->asCell();
+        if (Heap::isMarked(cell))
+            continue;
+
+        WeakHandleOwner* weakOwner = node->weakOwner();
+        if (!weakOwner)
+            continue;
+
+        if (!weakOwner->isReachableFromOpaqueRoots(Handle<Unknown>::wrapSlot(node->slot()), node->weakOwnerContext(), visitor))
+            continue;
+
+        heapRootVisitor.mark(node->slot());
+    }
+}
+
+void HandleHeap::finalizeWeakHandles()
+{
+    Node* end = m_weakList.end();
+    for (Node* node = m_weakList.begin(); node != end; node = m_nextToFinalize) {
+        m_nextToFinalize = node->next();
+
+        ASSERT(isValidWeakNode(node));
+        JSCell* cell = node->slot()->asCell();
+        if (Heap::isMarked(cell))
+            continue;
+
+        if (WeakHandleOwner* weakOwner = node->weakOwner()) {
+            weakOwner->finalize(Handle<Unknown>::wrapSlot(node->slot()), node->weakOwnerContext());
+            if (m_nextToFinalize != node->next()) // Owner deallocated node.
+                continue;
+        }
+
+        *node->slot() = JSValue();
+        SentinelLinkedList<Node>::remove(node);
+        m_immediateList.push(node);
+    }
+    
+    m_nextToFinalize = 0;
+}
+
+void HandleHeap::writeBarrier(HandleSlot slot, const JSValue& value)
+{
+    ASSERT(!m_nextToFinalize); // Forbid assignment to handles during the finalization phase, since it would violate many GC invariants.
+
+    if (!value == !*slot && slot->isCell() == value.isCell())
+        return;
+
+    Node* node = toNode(slot);
+    SentinelLinkedList<Node>::remove(node);
+    if (!value || !value.isCell()) {
+        m_immediateList.push(node);
+        return;
+    }
+
+    if (node->isWeak()) {
+        m_weakList.push(node);
+        return;
+    }
+
+    m_strongList.push(node);
+}
+
+unsigned HandleHeap::protectedGlobalObjectCount()
+{
+    unsigned count = 0;
+    Node* end = m_strongList.end();
+    for (Node* node = m_strongList.begin(); node != end; node = node->next()) {
+        JSValue value = *node->slot();
+        if (value.isObject() && asObject(value.asCell())->isGlobalObject())
+            count++;
+    }
+    return count;
+}
+
+#if !ASSERT_DISABLED
+bool HandleHeap::isValidWeakNode(Node* node)
+{
+    if (!node->isWeak())
+        return false;
+
+    JSValue value = *node->slot();
+    if (!value || !value.isCell())
+        return false;
+
+    JSCell* cell = value.asCell();
+    if (!cell || !cell->structure())
+        return false;
+
+#if ENABLE(JSC_ZOMBIES)
+    if (cell->isZombie())
+        return false;
+#endif
+
+    return true;
+}
+#endif
+
+} // namespace JSC