Jankometer: Generalize the code more. Add better support for monitoring IO thread.

base/message_loop.h

 // 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.
 
 #ifndef BASE_MESSAGE_LOOP_H_
 #define BASE_MESSAGE_LOOP_H_
 
 #include <queue>
 #include <string>
 
+#include "base/basictypes.h"
 #include "base/histogram.h"
 #include "base/message_pump.h"
 #include "base/observer_list.h"
 #include "base/ref_counted.h"
 #include "base/scoped_ptr.h"
 #include "base/task.h"
 
 #if defined(OS_WIN)
 // We need this to declare base::MessagePumpWin::Dispatcher, which we should
 // really just eliminate.
@@ skipping 30 matching lines @@
 //   MessageLoop::current()->SetNestableTasksAllowed(true);
 //   HRESULT hr = DoDragDrop(...); // Implicitly runs a modal message loop here.
 //   MessageLoop::current()->SetNestableTasksAllowed(old_state);
 //   // Process hr  (the result returned by DoDragDrop().
 //
 // Please be SURE your task is reentrant (nestable) and all global variables
 // are stable and accessible before calling SetNestableTasksAllowed(true).
 //
 class MessageLoop : public base::MessagePump::Delegate {
  public:
+  // A TaskObserver is an object that receives task notifications from the
+  // MessageLoop.
+  //
+  // NOTE: A TaskObserver implementation should be extremely fast!
+  class TaskObserver {
+   public:
+    TaskObserver() {}
+
+    // This method is called before processing a task.
+    virtual void WillProcessTask(base::TimeTicks birth_time) = 0;
+
+    // This method is called after processing a task.
+    virtual void DidProcessTask() = 0;
+
+   protected:
+    virtual ~TaskObserver() {}
+  };
+
   static void EnableHistogrammer(bool enable_histogrammer);
 
   // A DestructionObserver is notified when the current MessageLoop is being
   // destroyed.  These obsevers are notified prior to MessageLoop::current()
   // being changed to return NULL.  This gives interested parties the chance to
   // do final cleanup that depends on the MessageLoop.
   //
   // NOTE: Any tasks posted to the MessageLoop during this notification will
   // not be run.  Instead, they will be deleted.
   //
@@ skipping 177 matching lines @@
   // exception filter that was active when Run() was called. This can happen
   // if some third party code call SetUnhandledExceptionFilter() and never
   // restores the previous filter.
   void set_exception_restoration(bool restore) {
     exception_restoration_ = restore;
   }
 
   // Returns true if we are currently running a nested message loop.
   bool IsNested();
 
+  // These functions can only be called on the same thread that |this| is
+  // running on.
+  void AddTaskObserver(TaskObserver* task_observer);
+  void RemoveTaskObserver(TaskObserver* task_observer);
+
 #if defined(OS_WIN)
   typedef base::MessagePumpWin::Dispatcher Dispatcher;
-  typedef base::MessagePumpWin::Observer Observer;
+  typedef base::MessagePumpForUI::Observer Observer;
 #elif !defined(OS_MACOSX)
   typedef base::MessagePumpForUI::Dispatcher Dispatcher;
   typedef base::MessagePumpForUI::Observer Observer;
 #endif
 
   //----------------------------------------------------------------------------
  protected:
   struct RunState {
     // Used to count how many Run() invocations are on the stack.
     int run_depth;
@@ skipping 155 matching lines @@
   // will be handled by the TimerManager.
   TaskQueue incoming_queue_;
   // Protect access to incoming_queue_.
   Lock incoming_queue_lock_;
 
   RunState* state_;
 
   // The next sequence number to use for delayed tasks.
   int next_sequence_num_;
 
+  ObserverList<TaskObserver> task_observers_;
+
   DISALLOW_COPY_AND_ASSIGN(MessageLoop);
 };
 
 //-----------------------------------------------------------------------------
 // MessageLoopForUI extends MessageLoop with methods that are particular to a
 // MessageLoop instantiated with TYPE_UI.
 //
 // This class is typically used like so:
 //   MessageLoopForUI::current()->...call some method...
 //
 class MessageLoopForUI : public MessageLoop {
  public:
   MessageLoopForUI() : MessageLoop(TYPE_UI) {
   }
 
   // Returns the MessageLoopForUI of the current thread.
   static MessageLoopForUI* current() {
     MessageLoop* loop = MessageLoop::current();
     DCHECK_EQ(MessageLoop::TYPE_UI, loop->type());
     return static_cast<MessageLoopForUI*>(loop);
   }
 
 #if defined(OS_WIN)
-  void WillProcessMessage(const MSG& message);
   void DidProcessMessage(const MSG& message);
-  void PumpOutPendingPaintMessages();
-#endif
+#endif  // defined(OS_WIN)
 
 #if !defined(OS_MACOSX)
   // Please see message_pump_win/message_pump_glib for definitions of these
   // methods.
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
   void Run(Dispatcher* dispatcher);
 
  protected:
   // TODO(rvargas): Make this platform independent.
   base::MessagePumpForUI* pump_ui() {
     return static_cast<base::MessagePumpForUI*>(pump_.get());
   }
-#endif  // defined(OS_MACOSX)
+#endif  // !defined(OS_MACOSX)
 };
 
 // Do not add any member variables to MessageLoopForUI!  This is important b/c
 // MessageLoopForUI is often allocated via MessageLoop(TYPE_UI).  Any extra
 // data that you need should be stored on the MessageLoop's pump_ instance.
 COMPILE_ASSERT(sizeof(MessageLoop) == sizeof(MessageLoopForUI),
                MessageLoopForUI_should_not_have_extra_member_variables);
 
 //-----------------------------------------------------------------------------
 // MessageLoopForIO extends MessageLoop with methods that are particular to a
 // MessageLoop instantiated with TYPE_IO.
 //
 // This class is typically used like so:
 //   MessageLoopForIO::current()->...call some method...
 //
 class MessageLoopForIO : public MessageLoop {
  public:
+#if defined(OS_WIN)
+  typedef base::MessagePumpForIO::IOHandler IOHandler;
+  typedef base::MessagePumpForIO::IOContext IOContext;
+  typedef base::MessagePumpForIO::IOObserver IOObserver;
+#elif defined(OS_POSIX)
+  typedef base::MessagePumpLibevent::Watcher Watcher;
+  typedef base::MessagePumpLibevent::FileDescriptorWatcher
+      FileDescriptorWatcher;
+  typedef base::MessagePumpLibevent::IOObserver IOObserver;
+
+  enum Mode {
+    WATCH_READ = base::MessagePumpLibevent::WATCH_READ,
+    WATCH_WRITE = base::MessagePumpLibevent::WATCH_WRITE,
+    WATCH_READ_WRITE = base::MessagePumpLibevent::WATCH_READ_WRITE
+  };
+
+#endif
+
   MessageLoopForIO() : MessageLoop(TYPE_IO) {
   }
 
   // Returns the MessageLoopForIO of the current thread.
   static MessageLoopForIO* current() {
     MessageLoop* loop = MessageLoop::current();
     DCHECK_EQ(MessageLoop::TYPE_IO, loop->type());
     return static_cast<MessageLoopForIO*>(loop);
   }
 
+  void AddIOObserver(IOObserver* io_observer) {
+    pump_io()->AddIOObserver(io_observer);
+  }
+
+  void RemoveIOObserver(IOObserver* io_observer) {
+    pump_io()->RemoveIOObserver(io_observer);
+  }
+
 #if defined(OS_WIN)
-  typedef base::MessagePumpForIO::IOHandler IOHandler;
-  typedef base::MessagePumpForIO::IOContext IOContext;
-
   // Please see MessagePumpWin for definitions of these methods.
   void RegisterIOHandler(HANDLE file_handle, IOHandler* handler);
   bool WaitForIOCompletion(DWORD timeout, IOHandler* filter);
 
  protected:
   // TODO(rvargas): Make this platform independent.
   base::MessagePumpForIO* pump_io() {
     return static_cast<base::MessagePumpForIO*>(pump_.get());
   }
 
 #elif defined(OS_POSIX)
-  typedef base::MessagePumpLibevent::Watcher Watcher;
-  typedef base::MessagePumpLibevent::FileDescriptorWatcher
-      FileDescriptorWatcher;
-
-  enum Mode {
-    WATCH_READ = base::MessagePumpLibevent::WATCH_READ,
-    WATCH_WRITE = base::MessagePumpLibevent::WATCH_WRITE,
-    WATCH_READ_WRITE = base::MessagePumpLibevent::WATCH_READ_WRITE
-  };
-
   // Please see MessagePumpLibevent for definition.
   bool WatchFileDescriptor(int fd,
                            bool persistent,
                            Mode mode,
                            FileDescriptorWatcher *controller,
                            Watcher *delegate);
+
+ private:
+  base::MessagePumpLibevent* pump_io() {
+    return static_cast<base::MessagePumpLibevent*>(pump_.get());
+  }
 #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_