Home | History | Annotate | Download | only in xml 
      1 /*
      2  * Copyright (C) 2010 Julien Chaffraix <jchaffraix (at) webkit.org>
      3  * All right reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  *
     14  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     15  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     16  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     17  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     18  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     19  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     20  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     24  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     25  */
     26 
     27 #ifndef XMLHttpRequestProgressEventThrottle_h
     28 #define XMLHttpRequestProgressEventThrottle_h
     29 
     30 #include "platform/Timer.h"
     31 #include "platform/heap/Handle.h"
     32 #include "wtf/OwnPtr.h"
     33 #include "wtf/PassRefPtr.h"
     34 #include "wtf/Vector.h"
     35 #include "wtf/text/AtomicString.h"
     36 
     37 namespace blink {
     38 
     39 class Event;
     40 class EventTarget;
     41 class XMLHttpRequestProgressEvent;
     42 
     43 // This class implements the XHR2 ProgressEvent dispatching:
     44 //   "dispatch a progress event named progress about every 50ms or for every
     45 //   byte received, whichever is least frequent".
     46 //
     47 // readystatechange events also go through this class since ProgressEvents and
     48 // readystatechange events affect each other.
     49 //
     50 // In the comments for this class:
     51 // - "progress" event means an event named "progress"
     52 // - ProgressEvent means an event using the ProgressEvent interface defined in
     53 //   the spec.
     54 class XMLHttpRequestProgressEventThrottle FINAL : public TimerBase {
     55     DISALLOW_ALLOCATION();
     56 public:
     57     enum DeferredEventAction {
     58         Ignore,
     59         Clear,
     60         Flush,
     61     };
     62 
     63     explicit XMLHttpRequestProgressEventThrottle(EventTarget*);
     64     virtual ~XMLHttpRequestProgressEventThrottle();
     65 
     66     // Dispatches a ProgressEvent.
     67     //
     68     // Special treatment for events named "progress" is implemented to dispatch
     69     // them at the required frequency. If this object is suspended, the given
     70     // ProgressEvent overwrites the existing. I.e. only the latest one gets
     71     // queued. If the timer is running, this method just updates
     72     // m_lengthComputable, m_loaded and m_total. They'll be used on next
     73     // fired() call.
     74     void dispatchProgressEvent(const AtomicString&, bool lengthComputable, unsigned long long loaded, unsigned long long total);
     75     // Dispatches the given event after operation about the "progress" event
     76     // depending on the value of the ProgressEventAction argument.
     77     void dispatchReadyStateChangeEvent(PassRefPtrWillBeRawPtr<Event>, DeferredEventAction);
     78 
     79     void suspend();
     80     void resume();
     81 
     82     void trace(Visitor*);
     83 
     84 private:
     85     // The main purpose of this class is to throttle the "progress"
     86     // ProgressEvent dispatching. This class represents such a deferred
     87     // "progress" ProgressEvent.
     88     class DeferredEvent;
     89     static const double minimumProgressEventDispatchingIntervalInSeconds;
     90 
     91     virtual void fired() OVERRIDE;
     92     void dispatchDeferredEvent();
     93 
     94     // Non-Oilpan, keep a weak pointer to our XMLHttpRequest object as it is
     95     // the one holding us. With Oilpan, a simple strong Member can be used -
     96     // this XMLHttpRequestProgressEventThrottle (part) object dies together
     97     // with the XMLHttpRequest object.
     98     RawPtrWillBeMember<EventTarget> m_target;
     99 
    100     // A slot for the deferred "progress" ProgressEvent. When multiple events
    101     // arrive, only the last one is stored and others are discarded.
    102     const OwnPtr<DeferredEvent> m_deferred;
    103 };
    104 
    105 } // namespace blink
    106 
    107 #endif // XMLHttpRequestProgressEventThrottle_h
    108