Add support for base::Closure in the MessageLoop.

base/message_loop.h

 // Copyright (c) 2011 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.
 
 #ifndef BASE_MESSAGE_LOOP_H_
 #define BASE_MESSAGE_LOOP_H_
 #pragma once
 
 #include <queue>
 #include <string>
 
 #include "base/basictypes.h"
+#include "base/callback.h"
 #include "base/message_pump.h"
 #include "base/observer_list.h"
 #include "base/ref_counted.h"
 #include "base/synchronization/lock.h"
 #include "base/task.h"
 
 #if defined(OS_WIN)
 // We need this to declare base::MessagePumpWin::Dispatcher, which we should
 // really just eliminate.
 #include "base/message_pump_win.h"
@@ skipping 131 matching lines @@
 
   void PostDelayedTask(
       const tracked_objects::Location& from_here, Task* task, int64 delay_ms);
 
   void PostNonNestableTask(
       const tracked_objects::Location& from_here, Task* task);
 
   void PostNonNestableDelayedTask(
       const tracked_objects::Location& from_here, Task* task, int64 delay_ms);
 
+  void PostClosure(
+      const tracked_objects::Location& from_here,
+      const base::Closure& closure);
+
+  void PostDelayedClosure(
+      const tracked_objects::Location& from_here,
+      const base::Closure& closure, int64 delay_ms);
+
+  void PostNonNestableClosure(
+      const tracked_objects::Location& from_here,
+      const base::Closure& closure);
+
+  void PostNonNestableDelayedClosure(
+      const tracked_objects::Location& from_here,
+      const base::Closure& closure, int64 delay_ms);
+
   // A variant on PostTask that deletes the given object.  This is useful
   // if the object needs to live until the next run of the MessageLoop (for
   // example, deleting a RenderProcessHost from within an IPC callback is not
   // good).
   //
   // NOTE: This method may be called on any thread.  The object will be deleted
   // on the thread that executes MessageLoop::Run().  If this is not the same
   // as the thread that calls PostDelayedTask(FROM_HERE, ), then T MUST inherit
   // from RefCountedThreadSafe<T>!
   template <class T>
@@ skipping 163 matching lines @@
    public:
     explicit AutoRunState(MessageLoop* loop);
     ~AutoRunState();
    private:
     MessageLoop* loop_;
     RunState* previous_state_;
   };
 
   // This structure is copied around by value.
   struct PendingTask {
-    PendingTask(Task* task, bool nestable)
-        : task(task), sequence_num(0), nestable(nestable) {
+    PendingTask(Task* task, base::TimeTicks delayed_run_time, bool nestable)
+        : task(task), delayed_run_time(delayed_run_time), sequence_num(0),
+          nestable(nestable) {
+    }
+
+    PendingTask(const base::Closure& closure, base::TimeTicks delayed_run_time,
+                bool nestable)
+        : task(NULL), closure(closure), delayed_run_time(delayed_run_time),
+          sequence_num(0), nestable(nestable) {
     }
 
     // Used to support sorting.
     bool operator<(const PendingTask& other) const;
 
     Task* task;                        // The task to run.

[darin (slow to review), 2011/02/15 05:05:47]

It would be nice to implement the old Task-based methods in terms of Closure! :)

[awong, 2011/02/15 08:24:42]

Hah...yes it would.  I was initially thinking of a less intrusive first-step.
But, you're right...being conservative here doesn't gain us much.

To confirm, we will be throwing the whole world on top of the Callback<>
implementation now.

+    base::Closure closure;             // The Closure to run if task == NULL.
     base::TimeTicks delayed_run_time;  // The time when the task should be run.
     int sequence_num;                  // Secondary sort key for run time.
     bool nestable;                     // OK to dispatch from a nested loop.
   };
 
   class TaskQueue : public std::queue<PendingTask> {
    public:
     void Swap(TaskQueue* queue) {
       c.swap(queue->c);  // Calls std::deque::swap
     }
@@ skipping 25 matching lines @@
   // supports all saving and restoring of state, as is needed for any/all (ugly)
   // recursive calls.
   void RunInternal();
 
   // Called to process any delayed non-nestable tasks.
   bool ProcessNextDelayedNonNestableTask();
 
   // Runs the specified task and deletes it.
   void RunTask(Task* task);
 
+  // Runs the specified Closure.
+  void RunClosure(const base::Closure& closure);
+
   // Calls RunTask or queues the pending_task on the deferred task list if it
   // cannot be run right now.  Returns true if the task was run.
   bool DeferOrRunPendingTask(const PendingTask& pending_task);
 
   // Adds the pending task to delayed_work_queue_.
   void AddToDelayedWorkQueue(const PendingTask& pending_task);
 
+  // Adds the pending task to our incoming_queue_.
+  void AddToIncomingQueue(const PendingTask& pending_task);
+
   // Load tasks from the incoming_queue_ into work_queue_ if the latter is
   // empty.  The former requires a lock to access, while the latter is directly
   // accessible on this thread.
   void ReloadWorkQueue();
 
   // Delete tasks that haven't run yet without running them.  Used in the
   // destructor to make sure all the task's destructors get called.  Returns
   // true if some work was done.
   bool DeletePendingTasks();
 
-  // Post a task to our incomming queue.
-  void PostTask_Helper(const tracked_objects::Location& from_here, Task* task,
-                       int64 delay_ms, bool nestable);
+  // Calcuates the time at which a PendingTask should run.
+  base::TimeTicks CalculateDelayedRuntime(int64 delay_ms);
 
   // Start recording histogram info about events and action IF it was enabled
   // and IF the statistics recorder can accept a registration of our histogram.
   void StartHistogrammer();
 
   // Add occurence of event to our histogram, so that we can see what is being
   // done in a specific MessageLoop instance (i.e., specific thread).
   // If message_histogram_ is NULL, this is a no-op.
   void HistogramEvent(int event);
 
@@ skipping 27 matching lines @@
   // insider a (accidentally induced?) nested message pump.
   bool nestable_tasks_allowed_;
 
   bool exception_restoration_;
 
   std::string thread_name_;
   // A profiling histogram showing the counts of various messages and events.
   scoped_refptr<base::Histogram> message_histogram_;
 
   // A null terminated list which creates an incoming_queue of tasks that are
-  // acquired under a mutex for processing on this instance's thread. These tasks
-  // have not yet been sorted out into items for our work_queue_ vs items that
-  // will be handled by the TimerManager.
+  // acquired under a mutex for processing on this instance's thread. These
+  // tasks have not yet been sorted out into items for our work_queue_ vs items
+  // that will be handled by the TimerManager.
   TaskQueue incoming_queue_;
   // Protect access to incoming_queue_.
   mutable base::Lock incoming_queue_lock_;
 
   RunState* state_;
 
 #if defined(OS_WIN)
   base::TimeTicks high_resolution_timer_expiration_;
 #endif
 
@@ skipping 120 matching lines @@
 #endif  // defined(OS_POSIX)
 };
 
 // Do not add any member variables to MessageLoopForIO!  This is important b/c
 // MessageLoopForIO is often allocated via MessageLoop(TYPE_IO).  Any extra
 // data that you need should be stored on the MessageLoop's pump_ instance.
 COMPILE_ASSERT(sizeof(MessageLoop) == sizeof(MessageLoopForIO),
                MessageLoopForIO_should_not_have_extra_member_variables);
 
 #endif  // BASE_MESSAGE_LOOP_H_