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
33namespace JSC {
34
35class ExecState;
36class VM;
37
38class Watchdog {
39public:
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
62private:
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
105class Watchdog::Scope {
106public:
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
122private:
123    Watchdog* m_watchdog;
124};
125
126} // namespace JSC
127
128#endif // Watchdog_h
129