1 files changed, 274 insertions, 0 deletions
diff --git a/ipc/chromium/src/base/timer.h b/ipc/chromium/src/base/timer.h
new file mode 100644
index 000000000..b65f89392
--- /dev/null
+++ b/ipc/chromium/src/base/timer.h
@@ -0,0 +1,274 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// OneShotTimer and RepeatingTimer provide a simple timer API.  As the names
+// suggest, OneShotTimer calls you back once after a time delay expires.
+// RepeatingTimer on the other hand calls you back periodically with the
+// prescribed time interval.
+//
+// OneShotTimer and RepeatingTimer both cancel the timer when they go out of
+// scope, which makes it easy to ensure that you do not get called when your
+// object has gone out of scope.  Just instantiate a OneShotTimer or
+// RepeatingTimer as a member variable of the class for which you wish to
+// receive timer events.
+//
+// Sample RepeatingTimer usage:
+//
+//   class MyClass {
+//    public:
+//     void StartDoingStuff() {
+//       timer_.Start(TimeDelta::FromSeconds(1), this, &MyClass::DoStuff);
+//     }
+//     void StopDoingStuff() {
+//       timer_.Stop();
+//     }
+//    private:
+//     void DoStuff() {
+//       // This method is called every second to do stuff.
+//       ...
+//     }
+//     base::RepeatingTimer<MyClass> timer_;
+//   };
+//
+// Both OneShotTimer and RepeatingTimer also support a Reset method, which
+// allows you to easily defer the timer event until the timer delay passes once
+// again.  So, in the above example, if 0.5 seconds have already passed,
+// calling Reset on timer_ would postpone DoStuff by another 1 second.  In
+// other words, Reset is shorthand for calling Stop and then Start again with
+// the same arguments.
+
+#ifndef BASE_TIMER_H_
+#define BASE_TIMER_H_
+
+// IMPORTANT: If you change timer code, make sure that all tests (including
+// disabled ones) from timer_unittests.cc pass locally. Some are disabled
+// because they're flaky on the buildbot, but when you run them locally you
+// should be able to tell the difference.
+
+#include "base/logging.h"
+#include "base/task.h"
+#include "base/time.h"
+
+class MessageLoop;
+
+namespace base {
+
+//-----------------------------------------------------------------------------
+// This class is an implementation detail of OneShotTimer and RepeatingTimer.
+// Please do not use this class directly.
+//
+// This class exists to share code between BaseTimer<T> template instantiations.
+//
+class BaseTimer_Helper {
+ public:
+  // Stops the timer.
+  ~BaseTimer_Helper() {
+    OrphanDelayedTask();
+  }
+
+  // Returns true if the timer is running (i.e., not stopped).
+  bool IsRunning() const {
+    return !!delayed_task_;
+  }
+
+  // Returns the current delay for this timer.  May only call this method when
+  // the timer is running!
+  TimeDelta GetCurrentDelay() const {
+    DCHECK(IsRunning());
+    return delayed_task_->delay_;
+  }
+
+ protected:
+  BaseTimer_Helper() {}
+
+  // We have access to the timer_ member so we can orphan this task.
+  class TimerTask : public mozilla::Runnable {
+   public:
+    explicit TimerTask(TimeDelta delay) : delay_(delay) {
+      // timer_ is set in InitiateDelayedTask.
+    }
+    virtual ~TimerTask() {}
+    BaseTimer_Helper* timer_;
+    TimeDelta delay_;
+  };
+
+  // Used to orphan delayed_task_ so that when it runs it does nothing.
+  void OrphanDelayedTask();
+
+  // Used to initiated a new delayed task.  This has the side-effect of
+  // orphaning delayed_task_ if it is non-null.
+  void InitiateDelayedTask(TimerTask* timer_task);
+
+  RefPtr<TimerTask> delayed_task_;
+
+  DISALLOW_COPY_AND_ASSIGN(BaseTimer_Helper);
+};
+
+//-----------------------------------------------------------------------------
+// This class is an implementation detail of OneShotTimer and RepeatingTimer.
+// Please do not use this class directly.
+template <class Receiver, bool kIsRepeating>
+class BaseTimer : public BaseTimer_Helper {
+ public:
+  typedef void (Receiver::*ReceiverMethod)();
+
+  // Call this method to start the timer.  It is an error to call this method
+  // while the timer is already running.
+  void Start(TimeDelta delay, Receiver* receiver, ReceiverMethod method) {
+    DCHECK(!IsRunning());
+    InitiateDelayedTask(new TimerTask(delay, receiver, method));
+  }
+
+  // Call this method to stop the timer.  It is a no-op if the timer is not
+  // running.
+  void Stop() {
+    OrphanDelayedTask();
+  }
+
+  // Call this method to reset the timer delay of an already running timer.
+  void Reset() {
+    DCHECK(IsRunning());
+    InitiateDelayedTask(static_cast<TimerTask*>(delayed_task_.get())->Clone());
+  }
+
+ private:
+  typedef BaseTimer<Receiver, kIsRepeating> SelfType;
+
+  class TimerTask : public BaseTimer_Helper::TimerTask {
+   public:
+    TimerTask(TimeDelta delay, Receiver* receiver, ReceiverMethod method)
+        : BaseTimer_Helper::TimerTask(delay),
+          receiver_(receiver),
+          method_(method) {
+    }
+
+    virtual ~TimerTask() {
+      // This task may be getting cleared because the MessageLoop has been
+      // destructed.  If so, don't leave the Timer with a dangling pointer
+      // to this now-defunct task.
+      ClearBaseTimer();
+    }
+
+    NS_IMETHOD Run() override {
+      if (!timer_)  // timer_ is null if we were orphaned.
+        return NS_OK;
+      if (kIsRepeating)
+        ResetBaseTimer();
+      else
+        ClearBaseTimer();
+      DispatchToMethod(receiver_, method_, Tuple0());
+      return NS_OK;
+    }
+
+    TimerTask* Clone() const {
+      return new TimerTask(delay_, receiver_, method_);
+    }
+
+   private:
+    // Inform the Base that the timer is no longer active.
+    void ClearBaseTimer() {
+      if (timer_) {
+        SelfType* self = static_cast<SelfType*>(timer_);
+        // It is possible that the Timer has already been reset, and that this
+        // Task is old.  So, if the Timer points to a different task, assume
+        // that the Timer has already taken care of properly setting the task.
+        if (self->delayed_task_ == this)
+          self->delayed_task_ = nullptr;
+        // By now the delayed_task_ in the Timer does not point to us anymore.
+        // We should reset our own timer_ because the Timer can not do this
+        // for us in its destructor.
+        timer_ = NULL;
+      }
+    }
+
+    // Inform the Base that we're resetting the timer.
+    void ResetBaseTimer() {
+      DCHECK(timer_);
+      DCHECK(kIsRepeating);
+      SelfType* self = static_cast<SelfType*>(timer_);
+      self->Reset();
+    }
+
+    Receiver* receiver_;
+    ReceiverMethod method_;
+  };
+};
+
+//-----------------------------------------------------------------------------
+// A simple, one-shot timer.  See usage notes at the top of the file.
+template <class Receiver>
+class OneShotTimer : public BaseTimer<Receiver, false> {};
+
+//-----------------------------------------------------------------------------
+// A simple, repeating timer.  See usage notes at the top of the file.
+template <class Receiver>
+class RepeatingTimer : public BaseTimer<Receiver, true> {};
+
+//-----------------------------------------------------------------------------
+// A Delay timer is like The Button from Lost. Once started, you have to keep
+// calling Reset otherwise it will call the given method in the MessageLoop
+// thread.
+//
+// Once created, it is inactive until Reset is called. Once |delay| seconds have
+// passed since the last call to Reset, the callback is made. Once the callback
+// has been made, it's inactive until Reset is called again.
+//
+// If destroyed, the timeout is canceled and will not occur even if already
+// inflight.
+template <class Receiver>
+class DelayTimer {
+ public:
+  typedef void (Receiver::*ReceiverMethod)();
+
+  DelayTimer(TimeDelta delay, Receiver* receiver, ReceiverMethod method)
+      : receiver_(receiver),
+        method_(method),
+        delay_(delay) {
+  }
+
+  void Reset() {
+    DelayFor(delay_);
+  }
+
+ private:
+  void DelayFor(TimeDelta delay) {
+    trigger_time_ = Time::Now() + delay;
+
+    // If we already have a timer that will expire at or before the given delay,
+    // then we have nothing more to do now.
+    if (timer_.IsRunning() && timer_.GetCurrentDelay() <= delay)
+      return;
+
+    // The timer isn't running, or will expire too late, so restart it.
+    timer_.Stop();
+    timer_.Start(delay, this, &DelayTimer<Receiver>::Check);
+  }
+
+  void Check() {
+    if (trigger_time_.is_null())
+      return;
+
+    // If we have not waited long enough, then wait some more.
+    const Time now = Time::Now();
+    if (now < trigger_time_) {
+      DelayFor(trigger_time_ - now);
+      return;
+    }
+
+    (receiver_->*method_)();
+  }
+
+  Receiver *const receiver_;
+  const ReceiverMethod method_;
+  const TimeDelta delay_;
+
+  OneShotTimer<DelayTimer<Receiver> > timer_;
+  Time trigger_time_;
+};
+
+}  // namespace base
+
+#endif  // BASE_TIMER_H_