Restructor the the pump for nested loops.

base/message_pump_glib.h

 // Copyright (c) 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.
 
 #ifndef BASE_MESSAGE_PUMP_GLIB_H_
 #define BASE_MESSAGE_PUMP_GLIB_H_
 
 #include <glib.h>
 
 #include "base/message_pump.h"
 #include "base/scoped_ptr.h"
 #include "base/time.h"
 
 namespace base {
 
 // This class implements a MessagePump needed for TYPE_UI MessageLoops on
 // OS_LINUX platforms using GLib.
 class MessagePumpForUI : public MessagePump {
  public:
   MessagePumpForUI();
   ~MessagePumpForUI();
 
   virtual void Run(Delegate* delegate);
   virtual void Quit();
   virtual void ScheduleWork();
   virtual void ScheduleDelayedWork(const Time& delayed_work_time);
 
+  // Internal methods used for processing the pump callbacks.  They are
+  // public for simplicity but should not be used directly.  HandlePrepare
+  // is called during the prepare step of glib, and returns a timeout that
+  // will be passed to the poll.  HandleDispatch is called after the poll
+  // has completed.
+  int HandlePrepare();
+  void HandleDispatch();
+
  private:
   // We may make recursive calls to Run, so we save state that needs to be
   // separate between them in this structure type.
   struct RunState {
     Delegate* delegate;
 
     // Used to flag that the current Run() invocation should return ASAP.
     bool should_quit;
 
     // Used to count how many Run() invocations are on the stack.
     int run_depth;
+
+    // Used internally for controlling whether we want a message pump
+    // iteration to be blocking or not.
+    bool more_work_is_plausible;
   };
 
   RunState* state_;
 
   // This is a GLib structure that we can add event sources to.  We use the
   // default GLib context, which is the one to which all GTK events are
   // dispatched.
   GMainContext* context_;
 
   // This is the time when we need to do delayed work.
   Time delayed_work_time_;
 
   // The work source.  It is shared by all calls to Run and destroyed when
   // the message pump is destroyed.
   GSource* work_source_;
 
   DISALLOW_COPY_AND_ASSIGN(MessagePumpForUI);
 };
 
 }  // namespace base
 
 #endif  // BASE_MESSAGE_PUMP_GLIB_H_