runtime/Watchdog.h

   1 /*
   2  * Copyright (C) 2013 Apple 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. ``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 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 Watchdog_h
  27 #define Watchdog_h
  28
  29 #if OS(DARWIN)
  30 #include <dispatch/dispatch.h>
  31 #endif
  32
  33 namespace JSC {
  34
  35 class ExecState;
  36 class VM;
  37
  38 class Watchdog {
  39 public:
  40     class Scope;
  41
  42     Watchdog();
  43     ~Watchdog();
  44
  45     typedef bool (*ShouldTerminateCallback)(ExecState*, void* data1, void* data2);
  46     void setTimeLimit(VM&, double seconds, ShouldTerminateCallback = 0, void* data1 = 0, void* data2 = 0);
  47
  48     // This version of didFire() will check the elapsed CPU time and call the
  49     // callback (if needed) to determine if the watchdog should fire.
  50     bool didFire(ExecState*);
  51
  52     bool isEnabled();
  53
  54     // This version of didFire() is a more efficient version for when we want
  55     // to know if the watchdog has fired in the past, and not whether it should
  56     // fire right now.
  57     bool didFire() { return m_didFire; }
  58     JS_EXPORT_PRIVATE void fire();
  59
  60     void* timerDidFireAddress() { return &m_timerDidFire; }
  61
  62 private:
  63     void arm();
  64     void disarm();
  65     void startCountdownIfNeeded();
  66     void startCountdown(double limit);
  67     void stopCountdown();
  68     bool isArmed() { return !!m_reentryCount; }
  69
  70     // Platform specific timer implementation:
  71     void initTimer();
  72     void destroyTimer();
  73     void startTimer(double limit);
  74     void stopTimer();
  75
  76     // m_timerDidFire (above) indicates whether the timer fired. The Watchdog
  77     // still needs to check if the allowed CPU time has elapsed. If so, then
  78     // the Watchdog fires and m_didFire will be set.
  79     // NOTE: m_timerDidFire is only set by the platform specific timer
  80     // (probably from another thread) but is only cleared in the script thread.
  81     bool m_timerDidFire;
  82     bool m_didFire;
  83
  84     // All time units are in seconds.
  85     double m_limit;
  86     double m_startTime;
  87     double m_elapsedTime;
  88
  89     int m_reentryCount;
  90     bool m_isStopped;
  91
  92     ShouldTerminateCallback m_callback;
  93     void* m_callbackData1;
  94     void* m_callbackData2;
  95
  96 #if OS(DARWIN) && !PLATFORM(EFL) && !PLATFORM(GTK)
  97     dispatch_queue_t m_queue;
  98     dispatch_source_t m_timer;
  99 #endif
 100
 101     friend class Watchdog::Scope;
 102     friend class LLIntOffsetsExtractor;
 103 };
 104
 105 class Watchdog::Scope {
 106 public:
 107     Scope(Watchdog* watchdog)
 108         : m_watchdog(watchdog)
 109     {
 110         if (!watchdog)
 111             return;
 112         m_watchdog->arm();
 113     }
 114
 115     ~Scope()
 116     {
 117         if (!m_watchdog)
 118             return;
 119         m_watchdog->disarm();
 120     }
 121
 122 private:
 123     Watchdog* m_watchdog;
 124 };
 125
 126 } // namespace JSC
 127
 128 #endif // Watchdog_h