Lazily constructed bespoke cancellable timer task.

Source/platform/Timer.cpp

 /*
  * Copyright (C) 2006, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google 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
@@ skipping 11 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.
  */
 
 #include "config.h"
 #include "platform/Timer.h"
 
 #include "platform/TraceEvent.h"
 #include "public/platform/Platform.h"
+#include "public/platform/WebScheduler.h"
 #include "wtf/AddressSanitizer.h"
 #include "wtf/Atomics.h"
 #include "wtf/CurrentTime.h"
 #include "wtf/HashSet.h"
 #include <algorithm>
 #include <limits.h>
 #include <limits>
 #include <math.h>
 
 namespace blink {
 
 TimerBase::TimerBase()
     : m_nextFireTime(0)
     , m_unalignedNextFireTime(0)
     , m_repeatInterval(0)
-    , m_cancellableTaskFactory(WTF::bind(&TimerBase::run, this))
+    , m_cancellableTimerTask(nullptr)
     , m_webScheduler(Platform::current()->currentThread()->scheduler())
 #if ENABLE(ASSERT)
     , m_thread(currentThread())
 #endif
 {
 }
 
 TimerBase::~TimerBase()
 {
     stop();
 }
 
 void TimerBase::start(double nextFireInterval, double repeatInterval, const WebTraceLocation& caller)
 {
     ASSERT(m_thread == currentThread());
 
     m_location = caller;
     m_repeatInterval = repeatInterval;
     setNextFireTime(monotonicallyIncreasingTime(), nextFireInterval);
 }
 
 void TimerBase::stop()
 {
     ASSERT(m_thread == currentThread());
 
     m_repeatInterval = 0;
     m_nextFireTime = 0;
-    m_cancellableTaskFactory.cancel();
+    if (m_cancellableTimerTask)
+        m_cancellableTimerTask->cancel();
+    m_cancellableTimerTask = nullptr;
 }
 
 double TimerBase::nextFireInterval() const
 {
     ASSERT(isActive());
     double current = monotonicallyIncreasingTime();
     if (m_nextFireTime < current)
         return 0;
     return m_nextFireTime - current;
 }
 
 void TimerBase::setNextFireTime(double now, double delay)
 {
     ASSERT(m_thread == currentThread());
 
     m_unalignedNextFireTime = now + delay;
 
     double newTime = alignedFireTime(m_unalignedNextFireTime);
     if (m_nextFireTime != newTime) {
         m_nextFireTime = newTime;
         // Round the delay up to the nearest millisecond to be consistant with the
         // previous behavior of BlinkPlatformImpl::setSharedTimerFireInterval.
         long long delayMs = static_cast<long long>(ceil((newTime - now) * 1000.0));
         if (delayMs < 0)
             delayMs = 0;
-        m_webScheduler->postTimerTask(m_location, m_cancellableTaskFactory.cancelAndCreate(), delayMs);
+        if (m_cancellableTimerTask)
+            m_cancellableTimerTask->cancel();
+        m_cancellableTimerTask = new CancellableTimerTask(this);
+        m_webScheduler->postTimerTask(m_location, m_cancellableTimerTask, delayMs);
     }
 }
 
 NO_LAZY_SWEEP_SANITIZE_ADDRESS
-void TimerBase::run()
+void TimerBase::runInternal()
 {
     if (!canFire())
         return;
 
     TRACE_EVENT0("blink", "TimerBase::run");
     ASSERT_WITH_MESSAGE(m_thread == currentThread(), "Timer posted by %s %s was run on a different thread", m_location.functionName(), m_location.fileName());
     TRACE_EVENT_SET_SAMPLING_STATE("blink", "BlinkInternal");
 
     m_nextFireTime = 0;
     // Note: repeating timers drift, but this is preserving the functionality of the old timer heap.
     // See crbug.com/328700.
     if (m_repeatInterval)
         setNextFireTime(monotonicallyIncreasingTime(), m_repeatInterval);
     fired();
     TRACE_EVENT_SET_SAMPLING_STATE("blink", "Sleeping");
 }
 
 void TimerBase::didChangeAlignmentInterval(double now)
 {
     setNextFireTime(now, m_unalignedNextFireTime - now);
 }
 
 double TimerBase::nextUnalignedFireInterval() const
 {
     ASSERT(isActive());
     return std::max(m_unalignedNextFireTime - monotonicallyIncreasingTime(), 0.0);
 }
 
 } // namespace blink