JavaScriptCore-1218.tar.gz

[apple/javascriptcore.git] / runtime / Watchdog.h

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+/*
+ * Copyright (C) 2013 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#ifndef Watchdog_h
+#define Watchdog_h
+
+#if PLATFORM(MAC) || PLATFORM(IOS)
+#include <dispatch/dispatch.h>    
+#endif
+
+namespace JSC {
+
+class ExecState;
+class VM;
+
+class Watchdog {
+public:
+    class Scope;
+
+    Watchdog();
+    ~Watchdog();
+
+    typedef bool (*ShouldTerminateCallback)(ExecState*, void* data1, void* data2);
+    void setTimeLimit(VM&, double seconds, ShouldTerminateCallback = 0, void* data1 = 0, void* data2 = 0);
+
+    // This version of didFire() will check the elapsed CPU time and call the
+    // callback (if needed) to determine if the watchdog should fire.
+    bool didFire(ExecState*);
+
+    bool isEnabled();
+
+    // This version of didFire() is a more efficient version for when we want
+    // to know if the watchdog has fired in the past, and not whether it should
+    // fire right now.
+    JS_EXPORT_PRIVATE bool didFire() { return m_didFire; }
+    JS_EXPORT_PRIVATE void fire();
+
+    void* timerDidFireAddress() { return &m_timerDidFire; }
+
+private:
+    void arm();
+    void disarm();
+    void startCountdownIfNeeded();
+    void startCountdown(double limit);
+    void stopCountdown();
+    bool isArmed() { return !!m_reentryCount; }
+
+    // Platform specific timer implementation:
+    void initTimer();
+    void destroyTimer();
+    void startTimer(double limit);
+    void stopTimer();
+
+    // m_timerDidFire (above) indicates whether the timer fired. The Watchdog
+    // still needs to check if the allowed CPU time has elapsed. If so, then
+    // the Watchdog fires and m_didFire will be set.
+    // NOTE: m_timerDidFire is only set by the platform specific timer
+    // (probably from another thread) but is only cleared in the script thread.
+    bool m_timerDidFire;
+    bool m_didFire;
+
+    // All time units are in seconds.
+    double m_limit;
+    double m_startTime;
+    double m_elapsedTime;
+
+    int m_reentryCount;
+    bool m_isStopped;
+
+    ShouldTerminateCallback m_callback;
+    void* m_callbackData1;
+    void* m_callbackData2;
+
+#if PLATFORM(MAC) || PLATFORM(IOS)
+    dispatch_queue_t m_queue;
+    dispatch_source_t m_timer;
+#endif
+
+    friend class Watchdog::Scope;
+    friend class LLIntOffsetsExtractor;
+};
+
+class Watchdog::Scope {
+public:
+    Scope(Watchdog&);
+    ~Scope();
+
+private:
+    Watchdog& m_watchdog;
+};
+
+} // namespace JSC
+
+#endif // Watchdog_h