Mojo: First stab at making MessagePipes work across OS pipes.

mojo/system/local_message_pipe_endpoint.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/system/local_message_pipe_endpoint.h"
 
 #include <string.h>
 
 #include "base/logging.h"
 #include "mojo/system/message_in_transit.h"
 
 namespace mojo {
 namespace system {
 
 LocalMessagePipeEndpoint::LocalMessagePipeEndpoint()
     : is_open_(true),
       is_peer_open_(true) {
 }
 
 LocalMessagePipeEndpoint::~LocalMessagePipeEndpoint() {
   DCHECK(!is_open_);
 }
 
-void LocalMessagePipeEndpoint::OnPeerClose() {
+void LocalMessagePipeEndpoint::Close() {
+  DCHECK(is_open_);
+  is_open_ = false;
+  for (std::deque<MessageInTransit*>::iterator it = message_queue_.begin();
+       it != message_queue_.end();
+       ++it) {
+    (*it)->Destroy();
+  }
+  message_queue_.clear();
+}
+
+bool LocalMessagePipeEndpoint::OnPeerClose() {
   DCHECK(is_open_);
   DCHECK(is_peer_open_);
 
   MojoWaitFlags old_satisfied_flags = SatisfiedFlags();
   MojoWaitFlags old_satisfiable_flags = SatisfiableFlags();
   is_peer_open_ = false;
   MojoWaitFlags new_satisfied_flags = SatisfiedFlags();
   MojoWaitFlags new_satisfiable_flags = SatisfiableFlags();
 
   if (new_satisfied_flags != old_satisfied_flags ||
       new_satisfiable_flags != old_satisfiable_flags) {
     waiter_list_.AwakeWaitersForStateChange(new_satisfied_flags,
                                             new_satisfiable_flags);
   }
+
+  return true;
 }
 
-MojoResult LocalMessagePipeEndpoint::EnqueueMessage(
-    const void* bytes, uint32_t num_bytes,
-    const MojoHandle* handles, uint32_t num_handles,
-    MojoWriteMessageFlags /*flags*/) {
+MojoResult LocalMessagePipeEndpoint::EnqueueMessage(MessageInTransit* message) {
   DCHECK(is_open_);
   DCHECK(is_peer_open_);
 
   bool was_empty = message_queue_.empty();
-
-  // TODO(vtl): Eventually (with C++11), this should be an |emplace_back()|.
-  message_queue_.push_back(MessageInTransit::Create(bytes, num_bytes));
-  // TODO(vtl): Support sending handles.
-
+  message_queue_.push_back(message);
   if (was_empty) {
     waiter_list_.AwakeWaitersForStateChange(SatisfiedFlags(),
                                             SatisfiableFlags());
   }
 
   return MOJO_RESULT_OK;
 }
 
 void LocalMessagePipeEndpoint::CancelAllWaiters() {
   DCHECK(is_open_);
   waiter_list_.CancelAllWaiters();
 }
 
-void LocalMessagePipeEndpoint::Close() {
-  DCHECK(is_open_);
-  is_open_ = false;
-  for (std::deque<MessageInTransit*>::iterator it = message_queue_.begin();
-       it != message_queue_.end();
-       ++it) {
-    (*it)->Destroy();
-  }
-  message_queue_.clear();
-}
-
 MojoResult LocalMessagePipeEndpoint::ReadMessage(
     void* bytes, uint32_t* num_bytes,
     MojoHandle* handles, uint32_t* num_handles,
     MojoReadMessageFlags flags) {
   DCHECK(is_open_);
 
   const uint32_t max_bytes = num_bytes ? *num_bytes : 0;
   // TODO(vtl): We'll need this later:
   //  const uint32_t max_handles = num_handles ? *num_handles : 0;
 
-  if (message_queue_.empty())
-    return MOJO_RESULT_NOT_FOUND;
+  if (message_queue_.empty()) {
+    return is_peer_open_ ? MOJO_RESULT_NOT_FOUND :
+                           MOJO_RESULT_FAILED_PRECONDITION;
+  }
 
   // TODO(vtl): If |flags & MOJO_READ_MESSAGE_FLAG_MAY_DISCARD|, we could pop
   // and release the lock immediately.
   bool not_enough_space = false;
   MessageInTransit* const message = message_queue_.front();
   if (num_bytes)
     *num_bytes = message->data_size();
   if (message->data_size() <= max_bytes)
     memcpy(bytes, message->data(), message->data_size());
   else
@@ skipping 54 matching lines @@
   MojoWaitFlags satisfiable_flags = 0;
   if (!message_queue_.empty() || is_peer_open_)
     satisfiable_flags |= MOJO_WAIT_FLAG_READABLE;
   if (is_peer_open_)
     satisfiable_flags |= MOJO_WAIT_FLAG_WRITABLE;
   return satisfiable_flags;
 }
 
 }  // namespace system
 }  // namespace mojo
-