Refactor TimeBase to post tasks. Workers to use real Idle tasks.

Source/platform/Timer.h

 /*
  * Copyright (C) 2006 Apple Computer, 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
@@ skipping 45 matching lines @@
 
     void stop();
     bool isActive() const;
     const WebTraceLocation& location() const { return m_location; }
 
     double nextFireInterval() const;
     double nextUnalignedFireInterval() const;
     double repeatInterval() const { return m_repeatInterval; }
 
     void augmentRepeatInterval(double delta) {
-        setNextFireTime(m_nextFireTime + delta);
         m_repeatInterval += delta;
+        setNextFireTime(monotonicallyIncreasingTime(), m_repeatInterval);
     }
 
-    void didChangeAlignmentInterval();
+    void didChangeAlignmentInterval(double now);
 
     static void fireTimersInNestedEventLoop();
 
 private:
     virtual void fired() = 0;
 
     virtual double alignedFireTime(double fireTime) const { return fireTime; }
 
-    void checkConsistency() const;
-    void checkHeapIndex() const;
+    void setNextFireTime(double now, double delay);
 
-    void setNextFireTime(double);
+    void runInternal();
 
-    bool inHeap() const { return m_heapIndex != -1; }
+    // NOTE we can't use CancellableTaskFactory here, because the destructor of

[Sami, 2015/04/09 10:52:29]

"Some memory access" sounds a little vague. IIRC one of the problems was that
CancellableTaskFactory will have a pointer to the PartitionAlloc heap, which
isn't there anymore after Blink shuts down. Is that the problem with the unit
tests too or was that something else?

[alex clarke (OOO till 29th), 2015/04/10 15:29:40]

It was with the unit tests.  Clarified the comment slightly.

+    // CancellableTaskFactory::CancellableTask does some memory access.  Normally that's fine
+    // but some of the unit tests leave don't shutdown cleanly, leaving dangling tasks pointing
+    // to deleted memory, which cause CancellableTaskFactory::CancellableTask's destructor to segfault.
+    class CancellableTimerTask : public WebThread::Task {
+        WTF_MAKE_NONCOPYABLE(CancellableTimerTask);
 
-    bool hasValidHeapPosition() const;
-    void updateHeapIfNeeded(double oldTime);
+    public:
+        explicit CancellableTimerTask(TimerBase* timer) : m_timer(timer) { }
 
-    void heapDecreaseKey();
-    void heapDelete();
-    void heapDeleteMin();
-    void heapIncreaseKey();
-    void heapInsert();
-    void heapPop();
-    void heapPopMin();
+        virtual ~CancellableTimerTask() { }
 
-    Vector<TimerBase*>& timerHeap() const { ASSERT(m_cachedThreadGlobalTimerHeap); return *m_cachedThreadGlobalTimerHeap; }
+        void run() override;
+
+        void cancel()
+        {
+            m_timer = nullptr;
+        }
+
+    private:
+        TimerBase* m_timer; // NOT OWNED
+    };
 
     double m_nextFireTime; // 0 if inactive
     double m_unalignedNextFireTime; // m_nextFireTime not considering alignment interval
     double m_repeatInterval; // 0 if not repeating
-    int m_heapIndex; // -1 if not in heap
-    unsigned m_heapInsertionOrder; // Used to keep order among equal-fire-time timers
-    Vector<TimerBase*>* m_cachedThreadGlobalTimerHeap;
     WebTraceLocation m_location;
+    CancellableTimerTask* m_cancellableTimerTask; // NOT OWNED
 
 #if ENABLE(ASSERT)
     ThreadIdentifier m_thread;
 #endif
 
     friend class ThreadTimers;
     friend class TimerHeapLessThanFunction;
     friend class TimerHeapReference;
 };
 
@@ skipping 35 matching lines @@
     // This raw pointer is safe as long as Timer<X> is held by the X itself (That's the case
     // in the current code base).
     GC_PLUGIN_IGNORE("363031")
     TimerFiredClass* m_object;
     TimerFiredFunction m_function;
 };
 
 inline bool TimerBase::isActive() const
 {
     ASSERT(m_thread == currentThread());
-    return m_nextFireTime;
+    return m_cancellableTimerTask;
 }
 
 }
 
 #endif