[mojo-edk] Add MojoWatch and MojoCancelWatch APIs

mojo/edk/system/data_pipe_producer_dispatcher.cc

 // Copyright 2013 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 "mojo/edk/system/data_pipe_producer_dispatcher.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <utility>
@@ skipping 67 matching lines @@
 Dispatcher::Type DataPipeProducerDispatcher::GetType() const {
   return Type::DATA_PIPE_PRODUCER;
 }
 
 MojoResult DataPipeProducerDispatcher::Close() {
   base::AutoLock lock(lock_);
   DVLOG(1) << "Closing data pipe producer " << pipe_id_;
   return CloseNoLock();
 }
 
+MojoResult DataPipeProducerDispatcher::Watch(
+    MojoHandleSignals signals,
+    const Watcher::WatchCallback& callback,
+    uintptr_t context) {
+  base::AutoLock lock(lock_);
+
+  if (is_closed_ || in_transit_)
+    return MOJO_RESULT_INVALID_ARGUMENT;
+
+  return awakable_list_.AddWatcher(
+      signals, callback, context, GetHandleSignalsStateNoLock());
+}
+
+MojoResult DataPipeProducerDispatcher::CancelWatch(uintptr_t context) {
+  base::AutoLock lock(lock_);
+
+  if (is_closed_ || in_transit_)
+    return MOJO_RESULT_INVALID_ARGUMENT;
+
+  return awakable_list_.RemoveWatcher(context);
+}
+
 MojoResult DataPipeProducerDispatcher::WriteData(const void* elements,
                                                  uint32_t* num_bytes,
                                                  MojoWriteDataFlags flags) {
   base::AutoLock lock(lock_);
   if (!shared_ring_buffer_ || in_transit_)
     return MOJO_RESULT_INVALID_ARGUMENT;
 
   if (in_two_phase_write_)
     return MOJO_RESULT_BUSY;
 
@@ skipping 332 matching lines @@
 
 void DataPipeProducerDispatcher::NotifyWrite(uint32_t num_bytes) {
   DVLOG(1) << "Data pipe producer " << pipe_id_ << " notifying peer: "
            << num_bytes << " bytes written. [control_port="
            << control_port_.name() << "]";
 
   SendDataPipeControlMessage(node_controller_, control_port_,
                              DataPipeCommand::DATA_WAS_WRITTEN, num_bytes);
 }
 
 void DataPipeProducerDispatcher::OnPortStatusChanged() {

[Anand Mistry (off Chromium), 2016/03/01 07:30:40]

Don't you need a RequestContext here as well? Same for
DataPipeConsumerDispatcher.

[Ken Rockot(use gerrit already), 2016/03/01 08:17:44]

Oops, done and done

   base::AutoLock lock(lock_);
 
   // We stop observing the control port as soon it's transferred, but this can
   // race with events which are raised right before that happens. This is fine
   // to ignore.
   if (transferred_)
     return;
 
   DVLOG(1) << "Control port status changed for data pipe producer " << pipe_id_;
 
@@ skipping 51 matching lines @@
   }
 
   if (peer_closed_ != was_peer_closed ||
       available_capacity_ != previous_capacity) {
     awakable_list_.AwakeForStateChange(GetHandleSignalsStateNoLock());
   }
 }
 
 }  // namespace edk
 }  // namespace mojo