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      1 /*
      2  * Copyright (C) 2011 Google Inc. All Rights Reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  *  THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
     14  *  EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     15  *  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     16  *  DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
     17  *  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     18  *  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     19  *  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
     20  *  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     21  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     22  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     23  *
     24  */
     25 
     26 #include "config.h"
     27 #include "ScriptedAnimationController.h"
     28 
     29 #if ENABLE(REQUEST_ANIMATION_FRAME)
     30 
     31 #include "Document.h"
     32 #include "Element.h"
     33 #include "FrameView.h"
     34 #include "RequestAnimationFrameCallback.h"
     35 
     36 namespace WebCore {
     37 
     38 ScriptedAnimationController::ScriptedAnimationController(Document* document)
     39     : m_document(document)
     40     , m_nextCallbackId(0)
     41     , m_suspendCount(0)
     42 {
     43 }
     44 
     45 void ScriptedAnimationController::suspend()
     46 {
     47     ++m_suspendCount;
     48 }
     49 
     50 void ScriptedAnimationController::resume()
     51 {
     52     --m_suspendCount;
     53     if (!m_suspendCount && m_callbacks.size())
     54         if (FrameView* fv = m_document->view())
     55             fv->scheduleAnimation();
     56 }
     57 
     58 ScriptedAnimationController::CallbackId ScriptedAnimationController::registerCallback(PassRefPtr<RequestAnimationFrameCallback> callback, Element* animationElement)
     59 {
     60     ScriptedAnimationController::CallbackId id = m_nextCallbackId++;
     61     callback->m_firedOrCancelled = false;
     62     callback->m_id = id;
     63     callback->m_element = animationElement;
     64     m_callbacks.append(callback);
     65     if (!m_suspendCount)
     66         if (FrameView* view = m_document->view())
     67             view->scheduleAnimation();
     68     return id;
     69 }
     70 
     71 void ScriptedAnimationController::cancelCallback(CallbackId id)
     72 {
     73     for (size_t i = 0; i < m_callbacks.size(); ++i) {
     74         if (m_callbacks[i]->m_id == id) {
     75             m_callbacks[i]->m_firedOrCancelled = true;
     76             m_callbacks.remove(i);
     77             return;
     78         }
     79     }
     80 }
     81 
     82 void ScriptedAnimationController::serviceScriptedAnimations(DOMTimeStamp time)
     83 {
     84     if (!m_callbacks.size() || m_suspendCount)
     85         return;
     86     // We want to run the callback for all elements in the document that have registered
     87     // for a callback and that are visible.  Running the callbacks can cause new callbacks
     88     // to be registered, existing callbacks to be cancelled, and elements to gain or lose
     89     // visibility so this code has to iterate carefully.
     90 
     91     // FIXME: Currently, this code doesn't do any visibility tests beyond checking display:
     92 
     93     // First, generate a list of callbacks to consider.  Callbacks registered from this point
     94     // on are considered only for the "next" frame, not this one.
     95     CallbackList callbacks(m_callbacks);
     96 
     97     // Firing the callback may cause the visibility of other elements to change.  To avoid
     98     // missing any callbacks, we keep iterating through the list of candiate callbacks and firing
     99     // them until nothing new becomes visible.
    100     bool firedCallback;
    101     do {
    102         firedCallback = false;
    103         // A previous iteration may have invalidated style (or layout).  Update styles for each iteration
    104         // for now since all we check is the existence of a renderer.
    105         m_document->updateStyleIfNeeded();
    106         for (size_t i = 0; i < callbacks.size(); ++i) {
    107             RequestAnimationFrameCallback* callback = callbacks[i].get();
    108             if (!callback->m_firedOrCancelled && (!callback->m_element || callback->m_element->renderer())) {
    109                 callback->m_firedOrCancelled = true;
    110                 callback->handleEvent(time);
    111                 firedCallback = true;
    112                 callbacks.remove(i);
    113                 break;
    114             }
    115         }
    116     } while (firedCallback);
    117 
    118     // Remove any callbacks we fired from the list of pending callbacks.
    119     for (size_t i = 0; i < m_callbacks.size();) {
    120         if (m_callbacks[i]->m_firedOrCancelled)
    121             m_callbacks.remove(i);
    122         else
    123             ++i;
    124     }
    125 
    126     if (m_callbacks.size())
    127         if (FrameView* view = m_document->view())
    128             view->scheduleAnimation();
    129 }
    130 
    131 }
    132 
    133 #endif
    134 
    135