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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/PassRefPtr.h"
33 #include "wtf/Vector.h"
34 #include "wtf/text/AtomicString.h"
35 
36 namespace WebCore {
37 
38 class Event;
39 class EventTarget;
40 
41 enum ProgressEventAction {
42     DoNotFlushProgressEvent,
43     FlushDeferredProgressEvent,
44     FlushProgressEvent
45 };
46 
47 // This implements the XHR2 progress event dispatching: "dispatch a progress event called progress
48 // about every 50ms or for every byte received, whichever is least frequent".
49 class XMLHttpRequestProgressEventThrottle FINAL : public TimerBase {
50     DISALLOW_ALLOCATION();
51 public:
52     explicit XMLHttpRequestProgressEventThrottle(EventTarget*);
53     virtual ~XMLHttpRequestProgressEventThrottle();
54 
55     // Dispatches a ProgressEvent.
56     //
57     // Special treatment for events named "progress" is implemented to dispatch
58     // them at the required frequency. If this object is suspended, the given
59     // ProgressEvent overwrites the existing. I.e. only the latest one gets
60     // queued. If the timer is running, this method just updates
61     // m_lengthComputable, m_loaded and m_total. They'll be used on next
62     // fired() call.
63     void dispatchProgressEvent(const AtomicString&, bool lengthComputable, unsigned long long loaded, unsigned long long total);
64     void dispatchReadyStateChangeEvent(PassRefPtrWillBeRawPtr<Event>, ProgressEventAction = DoNotFlushProgressEvent);
65 
66     void suspend();
67     void resume();
68 
69     void trace(Visitor*);
70 
71 private:
72     static const double minimumProgressEventDispatchingIntervalInSeconds;
73 
74     // Dispatches an event. If suspended, just queues the given event.
75     void dispatchEvent(PassRefPtrWillBeRawPtr<Event>);
76 
77     virtual void fired() OVERRIDE;
78     void dispatchDeferredEvents(Timer<XMLHttpRequestProgressEventThrottle>*);
79     bool flushDeferredProgressEvent();
80     void deliverProgressEvent();
81 
82     bool hasEventToDispatch() const;
83 
84     // Non-Oilpan, keep a weak pointer to our XMLHttpRequest object as it is
85     // the one holding us. With Oilpan, a simple strong Member can be used -
86     // this XMLHttpRequestProgressEventThrottle (part) object dies together
87     // with the XMLHttpRequest object.
88     RawPtrWillBeMember<EventTarget> m_target;
89 
90     bool m_lengthComputable;
91     unsigned long long m_loaded;
92     unsigned long long m_total;
93 
94     bool m_deferEvents;
95     RefPtrWillBeMember<Event> m_deferredProgressEvent;
96     WillBeHeapVector<RefPtrWillBeMember<Event> > m_deferredEvents;
97     Timer<XMLHttpRequestProgressEventThrottle> m_dispatchDeferredEventsTimer;
98 };
99 
100 } // namespace WebCore
101 
102 #endif // XMLHttpRequestProgressEventThrottle_h
103