| /* |
| * Copyright (C) 2013 Google 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. |
| * 3. Neither the name of Google Inc. nor the names of its contributors |
| * may be used to endorse or promote products derived from this |
| * software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT |
| * OWNER OR 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 CustomElementCallbackDispatcher_h |
| #define CustomElementCallbackDispatcher_h |
| |
| #include "wtf/Vector.h" |
| |
| namespace WebCore { |
| |
| class CustomElementCallbackQueue; |
| class CustomElementCallbackScheduler; |
| |
| class CustomElementCallbackDispatcher { |
| WTF_MAKE_NONCOPYABLE(CustomElementCallbackDispatcher); |
| public: |
| static CustomElementCallbackDispatcher& instance(); |
| |
| // This is stack allocated in many DOM callbacks. Make it cheap. |
| class CallbackDeliveryScope { |
| public: |
| CallbackDeliveryScope() |
| : m_savedElementQueueStart(s_elementQueueStart) |
| { |
| s_elementQueueStart = s_elementQueueEnd; |
| } |
| |
| ~CallbackDeliveryScope() |
| { |
| if (s_elementQueueStart != s_elementQueueEnd) |
| processElementQueueAndPop(); |
| s_elementQueueStart = m_savedElementQueueStart; |
| } |
| |
| private: |
| size_t m_savedElementQueueStart; |
| }; |
| |
| // Returns true if more work may have to be performed at the |
| // checkpoint by this or other workers (for example, this work |
| // invoked author scripts) |
| bool dispatch(); |
| |
| protected: |
| friend class CustomElementCallbackScheduler; |
| void enqueue(CustomElementCallbackQueue*); |
| |
| private: |
| CustomElementCallbackDispatcher() |
| { |
| // Add a null element as a sentinel. This makes it possible to |
| // identify elements queued when there is no |
| // CallbackDeliveryScope active. Also, if the processing stack |
| // is popped when empty, this sentinel will cause a null deref |
| // crash. |
| CustomElementCallbackQueue* sentinel = 0; |
| for (size_t i = 0; i < kNumSentinels; i++) |
| m_flattenedProcessingStack.append(sentinel); |
| ASSERT(s_elementQueueEnd == m_flattenedProcessingStack.size()); |
| } |
| |
| // The start of the element queue on the top of the processing |
| // stack. An offset into instance().m_flattenedProcessingStack. |
| static size_t s_elementQueueStart; |
| |
| // The end of the element queue on the top of the processing |
| // stack. A cache of instance().m_flattenedProcessingStack.size(). |
| static size_t s_elementQueueEnd; |
| |
| static bool inCallbackDeliveryScope() { return s_elementQueueStart; } |
| |
| typedef int ElementQueue; |
| static ElementQueue currentElementQueue() { return ElementQueue(s_elementQueueStart); } |
| |
| static void processElementQueueAndPop(); |
| void processElementQueueAndPop(size_t start, size_t end); |
| |
| // The processing stack, flattened. Element queues lower in the |
| // stack appear toward the head of the vector. The first element |
| // is a null sentinel value. |
| static const size_t kNumSentinels = 1; |
| Vector<CustomElementCallbackQueue*> m_flattenedProcessingStack; |
| }; |
| |
| } |
| |
| #endif // CustomElementCallbackDispatcher_h |