| /* |
| * Copyright (C) 2011 Apple Inc. All rights reserved. |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2 of the License, or (at your option) any later version. |
| * |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with this library; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| * |
| */ |
| |
| #ifndef ListableHandler_h |
| #define ListableHandler_h |
| |
| #include <stdint.h> |
| #include <wtf/Locker.h> |
| #include <wtf/Noncopyable.h> |
| #include <wtf/ThreadingPrimitives.h> |
| #include <wtf/TCSpinLock.h> |
| |
| namespace JSC { |
| |
| class MarkStack; |
| class MarkStackThreadSharedData; |
| class SlotVisitor; |
| |
| template<typename T> |
| class ListableHandler { |
| WTF_MAKE_NONCOPYABLE(ListableHandler); |
| |
| protected: |
| ListableHandler() |
| : m_nextAndFlag(0) |
| { |
| } |
| |
| virtual ~ListableHandler() { } |
| |
| T* next() const |
| { |
| return reinterpret_cast<T*>(m_nextAndFlag & ~1); |
| } |
| |
| private: |
| // Allow these classes to use ListableHandler::List. |
| friend class MarkStack; |
| friend class GCThreadSharedData; |
| friend class SlotVisitor; |
| |
| class List { |
| WTF_MAKE_NONCOPYABLE(List); |
| public: |
| List() |
| : m_first(0) |
| { |
| m_lock.Init(); |
| } |
| |
| void addThreadSafe(T* handler) |
| { |
| SpinLockHolder locker(&m_lock); |
| addNotThreadSafe(handler); |
| } |
| |
| bool hasNext() |
| { |
| return !!m_first; |
| } |
| |
| T* head() |
| { |
| return m_first; |
| } |
| |
| T* removeNext() |
| { |
| T* current = m_first; |
| T* next = current->next(); |
| current->m_nextAndFlag = 0; |
| m_first = next; |
| return current; |
| } |
| |
| void removeAll() |
| { |
| while (hasNext()) |
| removeNext(); |
| } |
| |
| private: |
| void addNotThreadSafe(T* handler) |
| { |
| if (handler->m_nextAndFlag & 1) |
| return; |
| handler->m_nextAndFlag = reinterpret_cast<uintptr_t>(m_first) | 1; |
| m_first = handler; |
| } |
| |
| SpinLock m_lock; |
| T* m_first; |
| }; |
| |
| uintptr_t m_nextAndFlag; |
| }; |
| |
| } // namespace JSC |
| |
| #endif // ListableHandler_h |