Provide an iOS message pump for IO implementation.

base/message_pump_libevent.cc

 // Copyright (c) 2012 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.
 
 #include "base/message_pump_libevent.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <unistd.h>
 
@@ skipping 126 matching lines @@
   }
   if (wakeup_pipe_out_ >= 0) {
     if (HANDLE_EINTR(close(wakeup_pipe_out_)) < 0)
       DPLOG(ERROR) << "close";
   }
   event_base_free(event_base_);
 }
 
 bool MessagePumpLibevent::WatchFileDescriptor(int fd,
                                               bool persistent,
-                                              Mode mode,
+                                              int mode,
                                               FileDescriptorWatcher *controller,
                                               Watcher *delegate) {
   DCHECK_GE(fd, 0);
   DCHECK(controller);
   DCHECK(delegate);
-  DCHECK(mode == WATCH_READ || mode == WATCH_WRITE || mode == WATCH_READ_WRITE);
+  DCHECK(mode == WATCH_READ || mode == WATCH_WRITE ||
+         mode == (WATCH_READ_WRITE));

[wtc, 2012/11/28 00:25:26]

Remove the parantheses around WATCH_READ_WRITE. You can
completely undo the change to this line.

[blundell, 2012/11/28 12:25:01]

Done.

   // WatchFileDescriptor should be called on the pump thread. It is not
   // threadsafe, and your watcher may never be registered.
   DCHECK(watch_file_descriptor_caller_checker_.CalledOnValidThread());
 
   int event_mask = persistent ? EV_PERSIST : 0;
-  if ((mode & WATCH_READ) != 0) {
+  if (mode & WATCH_READ) {
     event_mask |= EV_READ;
   }
-  if ((mode & WATCH_WRITE) != 0) {
+  if (mode & WATCH_WRITE) {
     event_mask |= EV_WRITE;
   }
 
   scoped_ptr<event> evt(controller->ReleaseEvent());
   if (evt.get() == NULL) {
     // Ownership is transferred to the controller.
     evt.reset(new event);
   } else {
     // Make sure we don't pick up any funky internal libevent masks.
     int old_interest_mask = evt.get()->ev_events &
@@ skipping 10 matching lines @@
     if (EVENT_FD(evt.get()) != fd) {
       NOTREACHED() << "FDs don't match" << EVENT_FD(evt.get()) << "!=" << fd;
       return false;
     }
   }
 
   // Set current interest mask and message pump for this event.
   event_set(evt.get(), fd, event_mask, OnLibeventNotification, controller);
 
   // Tell libevent which message pump this socket will belong to when we add it.
-  if (event_base_set(event_base_, evt.get()) != 0) {
+  if (event_base_set(event_base_, evt.get())) {
     return false;
   }
 
   // Add this socket to the list of monitored sockets.
-  if (event_add(evt.get(), NULL) != 0) {

[wtc, 2012/11/28 00:25:26]

Nit: I believe Mark did not ask for these two changes.

[blundell, 2012/11/28 12:25:01]

I extrapolated from his request for consistency on either using or not using "!=
0".

On 2012/11/28 00:25:26, wtc wrote:

+  if (event_add(evt.get(), NULL)) {
     return false;
   }
 
   // Transfer ownership of evt to controller.
   controller->Init(evt.release());
 
   controller->set_watcher(delegate);
   controller->set_pump(this);
 
   return true;
@@ skipping 165 matching lines @@
   // Remove and discard the wakeup byte.
   char buf;
   int nread = HANDLE_EINTR(read(socket, &buf, 1));
   DCHECK_EQ(nread, 1);
   that->processed_io_events_ = true;
   // Tell libevent to break out of inner loop.
   event_base_loopbreak(that->event_base_);
 }
 
 }  // namespace base