JavaScriptCore-1097.3.tar.gz

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

diff --git a/heap/WeakSet.cpp b/heap/WeakSet.cpp
new file mode 100644 (file)
index 0000000..d9c773c
--- /dev/null
+++ b/heap/WeakSet.cpp
@@ -0,0 +1,132 @@
+/*
+ * 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 "WeakSet.h"
+
+#include "Heap.h"
+
+namespace JSC {
+
+WeakSet::~WeakSet()
+{
+    WeakBlock* next = 0;
+    for (WeakBlock* block = m_blocks.head(); block; block = next) {
+        next = block->next();
+        WeakBlock::destroy(block);
+    }
+    m_blocks.clear();
+}
+
+void WeakSet::finalizeAll()
+{
+    for (WeakBlock* block = m_blocks.head(); block; block = block->next())
+        block->finalizeAll();
+}
+
+void WeakSet::visitLiveWeakImpls(HeapRootVisitor& visitor)
+{
+    for (WeakBlock* block = m_blocks.head(); block; block = block->next())
+        block->visitLiveWeakImpls(visitor);
+}
+
+void WeakSet::visitDeadWeakImpls(HeapRootVisitor& visitor)
+{
+    for (WeakBlock* block = m_blocks.head(); block; block = block->next())
+        block->visitDeadWeakImpls(visitor);
+}
+
+void WeakSet::sweep()
+{
+    WeakBlock* next;
+    for (WeakBlock* block = m_blocks.head(); block; block = next) {
+        next = block->next();
+
+        // If a block is completely empty, a new sweep won't have any effect.
+        if (!block->sweepResult().isNull() && block->sweepResult().blockIsFree)
+            continue;
+
+        block->takeSweepResult(); // Force a new sweep by discarding the last sweep.
+        block->sweep();
+    }
+}
+
+void WeakSet::shrink()
+{
+    WeakBlock* next;
+    for (WeakBlock* block = m_blocks.head(); block; block = next) {
+        next = block->next();
+
+        if (!block->sweepResult().isNull() && block->sweepResult().blockIsFree)
+            removeAllocator(block);
+    }
+}
+
+void WeakSet::resetAllocator()
+{
+    m_allocator = 0;
+    m_nextAllocator = m_blocks.head();
+}
+
+WeakBlock::FreeCell* WeakSet::findAllocator()
+{
+    if (WeakBlock::FreeCell* allocator = tryFindAllocator())
+        return allocator;
+
+    return addAllocator();
+}
+
+WeakBlock::FreeCell* WeakSet::tryFindAllocator()
+{
+    while (m_nextAllocator) {
+        WeakBlock* block = m_nextAllocator;
+        m_nextAllocator = m_nextAllocator->next();
+
+        block->sweep();
+        WeakBlock::SweepResult sweepResult = block->takeSweepResult();
+        if (sweepResult.freeList)
+            return sweepResult.freeList;
+    }
+
+    return 0;
+}
+
+WeakBlock::FreeCell* WeakSet::addAllocator()
+{
+    WeakBlock* block = WeakBlock::create();
+    m_heap->didAllocate(WeakBlock::blockSize);
+    m_blocks.append(block);
+    WeakBlock::SweepResult sweepResult = block->takeSweepResult();
+    ASSERT(!sweepResult.isNull() && sweepResult.freeList);
+    return sweepResult.freeList;
+}
+
+void WeakSet::removeAllocator(WeakBlock* block)
+{
+    m_blocks.remove(block);
+    WeakBlock::destroy(block);
+}
+
+} // namespace JSC