Lazily constructed bespoke cancellable timer task.

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 10 matching lines @@
  * 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 Timer_h
 #define Timer_h
 
 #include "platform/PlatformExport.h"
 #include "platform/heap/Handle.h"
-#include "platform/scheduler/CancellableTaskFactory.h"
 #include "public/platform/WebTraceLocation.h"
 #include "wtf/AddressSanitizer.h"
 #include "wtf/Noncopyable.h"
 #include "wtf/Threading.h"
 #include "wtf/Vector.h"
 
 namespace blink {
 
 // Time intervals are all in seconds.
 
@@ skipping 23 matching lines @@
     double repeatInterval() const { return m_repeatInterval; }
 
     void augmentRepeatInterval(double delta) {
         double now = monotonicallyIncreasingTime();
         setNextFireTime(now, m_nextFireTime - now + delta);
         m_repeatInterval += delta;
     }
 
     void didChangeAlignmentInterval(double now);
 
-#if defined(ADDRESS_SANITIZER)
-protected:
-    CancellableTaskFactory& cancellableTaskFactory() { return m_cancellableTaskFactory; }
-#endif
-
 private:
     virtual void fired() = 0;
 
     NO_LAZY_SWEEP_SANITIZE_ADDRESS
     virtual bool canFire() const { return true; }
 
     virtual double alignedFireTime(double fireTime) const { return fireTime; }
 
     void setNextFireTime(double now, double delay);
 
-    void run();
+    void runInternal();
+
+    class CancellableTimerTask final : public WebThread::Task {
+        WTF_MAKE_NONCOPYABLE(CancellableTimerTask);
+    public:
+        explicit CancellableTimerTask(TimerBase* timer) : m_timer(timer) { }
+
+        ~CancellableTimerTask() override { }

[sof, 2015/06/26 06:45:06]

I guess this needs to clear out m_timer's back reference ?

+
+        void run() override
+        {
+            if (m_timer) {
+                m_timer->m_cancellableTimerTask = nullptr;
+                m_timer->runInternal();
+            }
+        }
+
+        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
     WebTraceLocation m_location;
-    CancellableTaskFactory m_cancellableTaskFactory;
+    CancellableTimerTask* m_cancellableTimerTask; // NOT OWNED
     WebScheduler* m_webScheduler; // Not owned.
 
 #if ENABLE(ASSERT)
     ThreadIdentifier m_thread;
 #endif
 
     friend class ThreadTimers;
     friend class TimerHeapLessThanFunction;
     friend class TimerHeapReference;
 };
@@ skipping 14 matching lines @@
 };
 
 template <typename TimerFiredClass>
 class Timer : public TimerBase {
 public:
     typedef void (TimerFiredClass::*TimerFiredFunction)(Timer*);
 
     Timer(TimerFiredClass* o, TimerFiredFunction f)
         : m_object(o), m_function(f)
     {
-#if ENABLE(LAZY_SWEEPING) && defined(ADDRESS_SANITIZER)

[sof, 2015/06/25 14:03:42]

Looks like not replacing this with an alternative caused an Oilpan ASan
meltdown,


http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Linux%20Oilpan%...

-        if (IsGarbageCollectedType<TimerFiredClass>::value)
-            cancellableTaskFactory().setUnpoisonBeforeUpdate();
-#endif
     }
 
 protected:
     virtual void fired() override
     {
         (m_object->*m_function)(this);
     }
 
     NO_LAZY_SWEEP_SANITIZE_ADDRESS
     virtual bool canFire() const override
@@ skipping 10 matching lines @@
     // in the current code base).
     GC_PLUGIN_IGNORE("363031")
     TimerFiredClass* m_object;
     TimerFiredFunction m_function;
 };
 
 NO_LAZY_SWEEP_SANITIZE_ADDRESS
 inline bool TimerBase::isActive() const
 {
     ASSERT(m_thread == currentThread());
-    return m_cancellableTaskFactory.isPending();
+    return m_cancellableTimerTask;
 }
 
 } // namespace blink
 
 #endif // Timer_h