Provide an iOS message pump for IO implementation.

base/message_pump_libevent.cc

Index: base/message_pump_libevent.cc
diff --git a/base/message_pump_libevent.cc b/base/message_pump_libevent.cc
index 66acd86e6e0abef5559600f615d7c0c5b5217adf..2b9996405a33c4be70f85a8d201e9ac1a9e5fca5 100644
--- a/base/message_pump_libevent.cc
+++ b/base/message_pump_libevent.cc
@@ -144,22 +144,23 @@ MessagePumpLibevent::~MessagePumpLibevent() {
 
 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;
   }
 
@@ -190,12 +191,12 @@ bool MessagePumpLibevent::WatchFileDescriptor(int fd,
   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;
   }