Add FD watching support to message_pump_libevent.

This CL goes along the same lines as the WatchSocket code, but we really need better encapsulation for this class in generel.

Review URL: http://codereview.chromium.org/13129

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@6513 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 84 insertions, 14 deletions

diff --git a/base/message_loop.cc b/base/message_loop.cc
index 1145439..898fbfa 100644
--- a/base/message_loop.cc
+++ b/base/message_loop.cc
@@ -193,7 +193,7 @@ void MessageLoop::RunInternal() {
     return;
   }
 #endif
-  
+
   pump_->Run(this);
 }
 
@@ -206,10 +206,10 @@ bool MessageLoop::ProcessNextDelayedNonNestableTask() {
 
   if (deferred_non_nestable_work_queue_.empty())
     return false;
-  
+
   Task* task = deferred_non_nestable_work_queue_.front().task;
   deferred_non_nestable_work_queue_.pop();
-  
+
   RunTask(task);
   return true;
 }
@@ -420,7 +420,7 @@ bool MessageLoop::DoDelayedWork(Time* next_delayed_work_time) {
     *next_delayed_work_time = Time();
     return false;
   }
-  
+
   if (delayed_work_queue_.top().delayed_run_time > Time::Now()) {
     *next_delayed_work_time = delayed_work_queue_.top().delayed_run_time;
     return false;
@@ -428,7 +428,7 @@ bool MessageLoop::DoDelayedWork(Time* next_delayed_work_time) {
 
   PendingTask pending_task = delayed_work_queue_.top();
   delayed_work_queue_.pop();
-  
+
   if (!delayed_work_queue_.empty())
     *next_delayed_work_time = delayed_work_queue_.top().delayed_run_time;
 
@@ -593,12 +593,22 @@ bool MessageLoopForIO::WaitForIOCompletion(DWORD timeout, IOHandler* filter) {
 
 #elif defined(OS_POSIX)
 
-void MessageLoopForIO::WatchSocket(int socket, short interest_mask, 
+void MessageLoopForIO::WatchSocket(int socket, short interest_mask,
                                    struct event* e, Watcher* watcher) {
   pump_libevent()->WatchSocket(socket, interest_mask, e, watcher);
 }
 
+void MessageLoopForIO::WatchFileHandle(int fd, short interest_mask,
+                                       struct event* e, FileWatcher* watcher) {
+  pump_libevent()->WatchFileHandle(fd, interest_mask, e, watcher);
+}
+
+
 void MessageLoopForIO::UnwatchSocket(struct event* e) {
   pump_libevent()->UnwatchSocket(e);
 }
+
+void MessageLoopForIO::UnwatchFileHandle(struct event* e) {
+  pump_libevent()->UnwatchFileHandle(e);
+}
 #endif
diff --git a/base/message_loop.h b/base/message_loop.h
index 8f16d8e..69db8c1 100644
--- a/base/message_loop.h
+++ b/base/message_loop.h
@@ -473,11 +473,14 @@ class MessageLoopForIO : public MessageLoop {
 
 #elif defined(OS_POSIX)
   typedef base::MessagePumpLibevent::Watcher Watcher;
+  typedef base::MessagePumpLibevent::FileWatcher FileWatcher;
 
   // Please see MessagePumpLibevent for definitions of these methods.
   void WatchSocket(int socket, short interest_mask,
                    struct event* e, Watcher* watcher);
+  void WatchFileHandle(int fd, short interest_mask, event* e, FileWatcher*);
   void UnwatchSocket(struct event* e);
+  void UnwatchFileHandle(event* e);
 #endif  // defined(OS_POSIX)
 };
 
diff --git a/base/message_pump_libevent.cc b/base/message_pump_libevent.cc
index 0dd533e..a281980 100644
--- a/base/message_pump_libevent.cc
+++ b/base/message_pump_libevent.cc
@@ -26,7 +26,7 @@ static int SetNonBlocking(int fd)
 // Called if a byte is received on the wakeup pipe.
 void MessagePumpLibevent::OnWakeup(int socket, short flags, void* context) {
 
-  base::MessagePumpLibevent* that = 
+  base::MessagePumpLibevent* that =
               static_cast<base::MessagePumpLibevent*>(context);
   DCHECK(that->wakeup_pipe_out_ == socket);
 
@@ -60,7 +60,7 @@ bool MessagePumpLibevent::Init() {
   wakeup_pipe_in_ = fds[1];
 
   wakeup_event_ = new event;
-  event_set(wakeup_event_, wakeup_pipe_out_, EV_READ | EV_PERSIST, 
+  event_set(wakeup_event_, wakeup_pipe_out_, EV_READ | EV_PERSIST,
 	    OnWakeup, this);
   event_base_set(event_base_, wakeup_event_);
 
@@ -77,7 +77,7 @@ MessagePumpLibevent::~MessagePumpLibevent() {
   event_base_free(event_base_);
 }
 
-void MessagePumpLibevent::WatchSocket(int socket, short interest_mask, 
+void MessagePumpLibevent::WatchSocket(int socket, short interest_mask,
                                       event* e, Watcher* watcher) {
 
   // Set current interest mask and message pump for this event
@@ -91,13 +91,36 @@ void MessagePumpLibevent::WatchSocket(int socket, short interest_mask,
     NOTREACHED();
 }
 
+void MessagePumpLibevent::WatchFileHandle(int fd, short interest_mask,
+                                          event* e, FileWatcher* watcher) {
+  // Set current interest mask and message pump for this event
+  if ((interest_mask & EV_READ) != 0) {
+    event_set(e, fd, interest_mask, OnFileReadReadinessNotification, watcher);
+  } else {
+    event_set(e, fd, interest_mask, OnFileWriteReadinessNotification, watcher);
+  }
+
+  // Tell libevent which message pump this fd will belong to when we add it.
+  event_base_set(event_base_, e);
+
+  // Add this fd to the list of monitored sockets.
+  if (event_add(e, NULL))
+    NOTREACHED();
+}
+
 void MessagePumpLibevent::UnwatchSocket(event* e) {
   // Remove this socket from the list of monitored sockets.
   if (event_del(e))
     NOTREACHED();
 }
 
-void MessagePumpLibevent::OnReadinessNotification(int socket, short flags, 
+void MessagePumpLibevent::UnwatchFileHandle(event* e) {
+  // Remove this fd from the list of monitored fds.
+  if (event_del(e))
+    NOTREACHED();
+}
+
+void MessagePumpLibevent::OnReadinessNotification(int socket, short flags,
                                                   void* context) {
   // The given socket is ready for I/O.
   // Tell the owner what kind of I/O the socket is ready for.
@@ -105,6 +128,18 @@ void MessagePumpLibevent::OnReadinessNotification(int socket, short flags,
   watcher->OnSocketReady(flags);
 }
 
+void MessagePumpLibevent::OnFileReadReadinessNotification(int fd, short flags,
+                                                          void* context) {
+  FileWatcher* watcher = static_cast<FileWatcher*>(context);
+  watcher->OnFileReadReady(fd);
+}
+
+void MessagePumpLibevent::OnFileWriteReadinessNotification(int fd, short flags,
+                                                           void* context) {
+  FileWatcher* watcher = static_cast<FileWatcher*>(context);
+  watcher->OnFileWriteReady(fd);
+}
+
 // Reentrant!
 void MessagePumpLibevent::Run(Delegate* delegate) {
   DCHECK(keep_running_) << "Quit must have been called outside of Run!";
diff --git a/base/message_pump_libevent.h b/base/message_pump_libevent.h
index 9934f31..b54bc36 100644
--- a/base/message_pump_libevent.h
+++ b/base/message_pump_libevent.h
@@ -18,7 +18,7 @@ namespace base {
 // TODO(dkegel): add support for background file IO somehow
 class MessagePumpLibevent : public MessagePump {
  public:
-  // Used with WatchObject to asynchronously monitor the I/O readiness of a
+  // Used with WatchSocket to asynchronously monitor the I/O readiness of a
   // socket.
   class Watcher {
    public:
@@ -27,22 +27,38 @@ class MessagePumpLibevent : public MessagePump {
     virtual void OnSocketReady(short eventmask) = 0;
   };
 
+  // Used with WatchFileHandle to monitor I/O readiness for a File Handle.
+  class FileWatcher {
+   public:
+    virtual ~FileWatcher() {}
+    // Called from MessageLoop::Run when a non-blocking read/write can be made.
+    virtual void OnFileReadReady(int fd) = 0;
+    virtual void OnFileWriteReady(int fd) = 0;
+  };
+
   MessagePumpLibevent();
   virtual ~MessagePumpLibevent();
 
   // Have the current thread's message loop watch for a ready socket.
   // Caller must provide a struct event for this socket for libevent's use.
   // The event and interest_mask fields are defined in libevent.
-  // Returns true on success.  
+  // Returns true on success.
   // TODO(dkegel): hide libevent better; abstraction still too leaky
   // TODO(dkegel): better error handing
   // TODO(dkegel): switch to edge-triggered readiness notification
   void WatchSocket(int socket, short interest_mask, event* e, Watcher*);
 
+  // TODO(playmobil): Merge this with WatchSocket().
+  void WatchFileHandle(int fd, short interest_mask, event* e, FileWatcher*);
+
   // Stop watching a socket.
   // Event was previously initialized by WatchSocket.
   void UnwatchSocket(event* e);
 
+  // Stop watching a File Handle.
+  // Event was previously initialized by WatchFileHandle.
+  void UnwatchFileHandle(event* e);
+
   // MessagePump methods:
   virtual void Run(Delegate* delegate);
   virtual void Quit();
@@ -63,17 +79,23 @@ class MessagePumpLibevent : public MessagePump {
   // The time at which we should call DoDelayedWork.
   Time delayed_work_time_;
 
-  // Libevent dispatcher.  Watches all sockets registered with it, and sends 
+  // Libevent dispatcher.  Watches all sockets registered with it, and sends
   // readiness callbacks when a socket is ready for I/O.
   event_base* event_base_;
 
   // Called by libevent to tell us a registered socket is ready
   static void OnReadinessNotification(int socket, short flags, void* context);
 
+  // Called by libevent to tell us a registered fd is ready.
+  static void OnFileReadReadinessNotification(int fd, short flags,
+                                              void* context);
+  static void OnFileWriteReadinessNotification(int fd, short flags,
+                                               void* context);
+
   // Unix pipe used to implement ScheduleWork()
   // ... callback; called by libevent inside Run() when pipe is ready to read
   static void OnWakeup(int socket, short flags, void* context);
-  // ... write end; ScheduleWork() writes a single byte to it 
+  // ... write end; ScheduleWork() writes a single byte to it
   int wakeup_pipe_in_;
   // ... read end; OnWakeup reads it and then breaks Run() out of its sleep
   int wakeup_pipe_out_;