third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequestProgressEventThrottle.h

   1 /*
   2  * Copyright (C) 2010 Julien Chaffraix <jchaffraix@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/Forward.h"
  33 #include "wtf/OwnPtr.h"
  34 #include "wtf/PassRefPtr.h"
  35
  36 namespace blink {
  37
  38 class Event;
  39 class XMLHttpRequest;
  40
  41 // This class implements the XHR2 ProgressEvent dispatching:
  42 //   "dispatch a progress event named progress about every 50ms or for every
  43 //   byte received, whichever is least frequent".
  44 //
  45 // readystatechange events also go through this class since ProgressEvents and
  46 // readystatechange events affect each other.
  47 //
  48 // In the comments for this class:
  49 // - "progress" event means an event named "progress"
  50 // - ProgressEvent means an event using the ProgressEvent interface defined in
  51 //   the spec.
  52 class XMLHttpRequestProgressEventThrottle final : public GarbageCollectedFinalized<XMLHttpRequestProgressEventThrottle>, public TimerBase {
  53 public:
  54     static XMLHttpRequestProgressEventThrottle* create(XMLHttpRequest* eventTarget)
  55     {
  56         return new XMLHttpRequestProgressEventThrottle(eventTarget);
  57     }
  58     ~XMLHttpRequestProgressEventThrottle() override;
  59
  60     enum DeferredEventAction {
  61         Ignore,
  62         Clear,
  63         Flush,
  64     };
  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     // Need to promptly stop this timer when it is deemed finalizable.
  83     EAGERLY_FINALIZE();
  84     DECLARE_TRACE();
  85
  86 private:
  87     explicit XMLHttpRequestProgressEventThrottle(XMLHttpRequest*);
  88
  89     // The main purpose of this class is to throttle the "progress"
  90     // ProgressEvent dispatching. This class represents such a deferred
  91     // "progress" ProgressEvent.
  92     class DeferredEvent;
  93     static const double minimumProgressEventDispatchingIntervalInSeconds;
  94
  95     void fired() override;
  96     void dispatchDeferredEvent();
  97
  98     // Non-Oilpan, keep a weak pointer to our XMLHttpRequest object as it is
  99     // the one holding us. With Oilpan, a simple strong Member can be used -
 100     // this XMLHttpRequestProgressEventThrottle (part) object dies together
 101     // with the XMLHttpRequest object.
 102     Member<XMLHttpRequest> m_target;
 103
 104     // A slot for the deferred "progress" ProgressEvent. When multiple events
 105     // arrive, only the last one is stored and others are discarded.
 106     const OwnPtr<DeferredEvent> m_deferred;
 107 };
 108
 109 } // namespace blink
 110
 111 #endif // XMLHttpRequestProgressEventThrottle_h