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      1 /*
      2  * Copyright (C) 2006 Apple Computer, 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 COMPUTER, INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #ifndef Timer_h
     27 #define Timer_h
     28 
     29 #include "platform/PlatformExport.h"
     30 #include "platform/TraceLocation.h"
     31 #include "platform/heap/Handle.h"
     32 #include "wtf/Noncopyable.h"
     33 #include "wtf/Threading.h"
     34 #include "wtf/Vector.h"
     35 
     36 namespace blink {
     37 
     38 // Time intervals are all in seconds.
     39 
     40 class PLATFORM_EXPORT TimerBase {
     41     WTF_MAKE_NONCOPYABLE(TimerBase); WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED;
     42 public:
     43     TimerBase();
     44     virtual ~TimerBase();
     45 
     46     void start(double nextFireInterval, double repeatInterval, const TraceLocation&);
     47 
     48     void startRepeating(double repeatInterval, const TraceLocation& caller)
     49     {
     50         start(repeatInterval, repeatInterval, caller);
     51     }
     52     void startOneShot(double interval, const TraceLocation& caller)
     53     {
     54         start(interval, 0, caller);
     55     }
     56 
     57     void stop();
     58     bool isActive() const;
     59     const TraceLocation& location() const { return m_location; }
     60 
     61     double nextFireInterval() const;
     62     double nextUnalignedFireInterval() const;
     63     double repeatInterval() const { return m_repeatInterval; }
     64 
     65     void augmentRepeatInterval(double delta) {
     66         setNextFireTime(m_nextFireTime + delta);
     67         m_repeatInterval += delta;
     68     }
     69 
     70     void didChangeAlignmentInterval();
     71 
     72     static void fireTimersInNestedEventLoop();
     73 
     74 private:
     75     virtual void fired() = 0;
     76 
     77     virtual double alignedFireTime(double fireTime) const { return fireTime; }
     78 
     79     void checkConsistency() const;
     80     void checkHeapIndex() const;
     81 
     82     void setNextFireTime(double);
     83 
     84     bool inHeap() const { return m_heapIndex != -1; }
     85 
     86     bool hasValidHeapPosition() const;
     87     void updateHeapIfNeeded(double oldTime);
     88 
     89     void heapDecreaseKey();
     90     void heapDelete();
     91     void heapDeleteMin();
     92     void heapIncreaseKey();
     93     void heapInsert();
     94     void heapPop();
     95     void heapPopMin();
     96 
     97     Vector<TimerBase*>& timerHeap() const { ASSERT(m_cachedThreadGlobalTimerHeap); return *m_cachedThreadGlobalTimerHeap; }
     98 
     99     double m_nextFireTime; // 0 if inactive
    100     double m_unalignedNextFireTime; // m_nextFireTime not considering alignment interval
    101     double m_repeatInterval; // 0 if not repeating
    102     int m_heapIndex; // -1 if not in heap
    103     unsigned m_heapInsertionOrder; // Used to keep order among equal-fire-time timers
    104     Vector<TimerBase*>* m_cachedThreadGlobalTimerHeap;
    105     TraceLocation m_location;
    106 
    107 #if ENABLE(ASSERT)
    108     ThreadIdentifier m_thread;
    109 #endif
    110 
    111     friend class ThreadTimers;
    112     friend class TimerHeapLessThanFunction;
    113     friend class TimerHeapReference;
    114 };
    115 
    116 template <typename TimerFiredClass>
    117 class Timer FINAL : public TimerBase {
    118 public:
    119     typedef void (TimerFiredClass::*TimerFiredFunction)(Timer*);
    120 
    121     Timer(TimerFiredClass* o, TimerFiredFunction f)
    122         : m_object(o), m_function(f) { }
    123 
    124 private:
    125     virtual void fired() OVERRIDE { (m_object->*m_function)(this); }
    126 
    127     // FIXME: oilpan: TimerBase should be moved to the heap and m_object should be traced.
    128     // This raw pointer is safe as long as Timer<X> is held by the X itself (That's the case
    129     // in the current code base).
    130     GC_PLUGIN_IGNORE("363031")
    131     TimerFiredClass* m_object;
    132     TimerFiredFunction m_function;
    133 };
    134 
    135 inline bool TimerBase::isActive() const
    136 {
    137     ASSERT(m_thread == currentThread());
    138     return m_nextFireTime;
    139 }
    140 
    141 template <typename TimerFiredClass>
    142 class DeferrableOneShotTimer FINAL : private TimerBase {
    143 public:
    144     typedef void (TimerFiredClass::*TimerFiredFunction)(DeferrableOneShotTimer*);
    145 
    146     DeferrableOneShotTimer(TimerFiredClass* o, TimerFiredFunction f, double delay)
    147         : m_object(o)
    148         , m_function(f)
    149         , m_delay(delay)
    150         , m_shouldRestartWhenTimerFires(false)
    151     {
    152     }
    153 
    154     void restart(const TraceLocation& caller)
    155     {
    156         // Setting this boolean is much more efficient than calling startOneShot
    157         // again, which might result in rescheduling the system timer which
    158         // can be quite expensive.
    159 
    160         if (isActive()) {
    161             m_shouldRestartWhenTimerFires = true;
    162             return;
    163         }
    164         startOneShot(m_delay, caller);
    165     }
    166 
    167     using TimerBase::stop;
    168     using TimerBase::isActive;
    169 
    170 private:
    171     virtual void fired() OVERRIDE
    172     {
    173         if (m_shouldRestartWhenTimerFires) {
    174             m_shouldRestartWhenTimerFires = false;
    175             // FIXME: This should not be FROM_HERE.
    176             startOneShot(m_delay, FROM_HERE);
    177             return;
    178         }
    179 
    180         (m_object->*m_function)(this);
    181     }
    182 
    183     // FIXME: oilpan: TimerBase should be moved to the heap and m_object should be traced.
    184     // This raw pointer is safe as long as Timer<X> is held by the X itself (That's the case
    185     // in the current code base).
    186     GC_PLUGIN_IGNORE("363031")
    187     TimerFiredClass* m_object;
    188     TimerFiredFunction m_function;
    189 
    190     double m_delay;
    191     bool m_shouldRestartWhenTimerFires;
    192 };
    193 
    194 }
    195 
    196 #endif
    197