| /* |
| * Copyright (C) 2010 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. |
| */ |
| |
| #ifndef HandleStack_h |
| #define HandleStack_h |
| |
| #include <wtf/Assertions.h> |
| #include <wtf/BlockStack.h> |
| #include "Handle.h" |
| |
| #include <wtf/UnusedParam.h> |
| |
| namespace JSC { |
| |
| class LocalScope; |
| class HeapRootVisitor; |
| |
| class HandleStack { |
| public: |
| class Frame { |
| public: |
| HandleSlot m_next; |
| HandleSlot m_end; |
| }; |
| |
| HandleStack(); |
| |
| void enterScope(Frame&); |
| void leaveScope(Frame&); |
| |
| HandleSlot push(); |
| |
| void visit(HeapRootVisitor&); |
| |
| private: |
| void grow(); |
| void zapTo(Frame&); |
| HandleSlot findFirstAfter(HandleSlot); |
| |
| #ifndef NDEBUG |
| size_t m_scopeDepth; |
| #endif |
| BlockStack<JSValue> m_blockStack; |
| Frame m_frame; |
| }; |
| |
| inline void HandleStack::enterScope(Frame& lastFrame) |
| { |
| #ifndef NDEBUG |
| ++m_scopeDepth; |
| #endif |
| |
| lastFrame = m_frame; |
| } |
| |
| |
| |
| inline void HandleStack::zapTo(Frame& lastFrame) |
| { |
| #ifdef NDEBUG |
| UNUSED_PARAM(lastFrame); |
| #else |
| const Vector<HandleSlot>& blocks = m_blockStack.blocks(); |
| |
| if (lastFrame.m_end != m_frame.m_end) { // Zapping to a frame in a different block. |
| int i = blocks.size() - 1; |
| for ( ; blocks[i] + m_blockStack.blockLength != lastFrame.m_end; --i) { |
| for (int j = m_blockStack.blockLength - 1; j >= 0; --j) |
| blocks[i][j] = JSValue(); |
| } |
| |
| for (HandleSlot it = blocks[i] + m_blockStack.blockLength - 1; it != lastFrame.m_next - 1; --it) |
| *it = JSValue(); |
| |
| return; |
| } |
| |
| for (HandleSlot it = m_frame.m_next - 1; it != lastFrame.m_next - 1; --it) |
| *it = JSValue(); |
| #endif |
| } |
| |
| inline void HandleStack::leaveScope(Frame& lastFrame) |
| { |
| #ifndef NDEBUG |
| --m_scopeDepth; |
| #endif |
| |
| zapTo(lastFrame); |
| |
| if (lastFrame.m_end != m_frame.m_end) // Popping to a frame in a different block. |
| m_blockStack.shrink(lastFrame.m_end); |
| |
| m_frame = lastFrame; |
| } |
| |
| inline HandleSlot HandleStack::push() |
| { |
| ASSERT(m_scopeDepth); // Creating a Local outside of a LocalScope is a memory leak. |
| if (m_frame.m_next == m_frame.m_end) |
| grow(); |
| return m_frame.m_next++; |
| } |
| |
| } |
| |
| #endif |