Mojo: More plumbing required to transfer handles over MessagePipes.

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/dispatcher.h"
 #include "mojo/system/message_in_transit.h"
 
 namespace mojo {
 namespace system {
 
+LocalMessagePipeEndpoint::MessageQueueEntry::MessageQueueEntry()
+    : message(NULL) {
+}
+
+// See comment in header file.
+LocalMessagePipeEndpoint::MessageQueueEntry::MessageQueueEntry(
+    const MessageQueueEntry& other)
+    : message(NULL) {
+  DCHECK(!other.message);
+  DCHECK(other.dispatchers.empty());
+}
+
+LocalMessagePipeEndpoint::MessageQueueEntry::~MessageQueueEntry() {
+  if (message)
+    message->Destroy();
+}
+
 LocalMessagePipeEndpoint::LocalMessagePipeEndpoint()
     : is_open_(true),
       is_peer_open_(true) {
 }
 
 LocalMessagePipeEndpoint::~LocalMessagePipeEndpoint() {
   DCHECK(!is_open_);
 }
 
 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(
+MojoResult LocalMessagePipeEndpoint::CanEnqueueMessage(
+    const MessageInTransit* /*message*/,
+    const std::vector<Dispatcher*>* dispatchers) {
+  // TODO(vtl)
+  if (dispatchers) {
+    NOTIMPLEMENTED();
+    return MOJO_RESULT_UNIMPLEMENTED;
+  }
+  return MOJO_RESULT_OK;
+}
+
+void LocalMessagePipeEndpoint::EnqueueMessage(
     MessageInTransit* message,
-    const std::vector<Dispatcher*>* dispatchers) {
+    std::vector<scoped_refptr<Dispatcher> >* dispatchers) {
   DCHECK(is_open_);
   DCHECK(is_peer_open_);
 
   // TODO(vtl)
-  if (dispatchers) {
-    message->Destroy();
-    return MOJO_RESULT_UNIMPLEMENTED;
-  }
+  DCHECK(!dispatchers || dispatchers->empty());
 
   bool was_empty = message_queue_.empty();
-  message_queue_.push_back(message);
+  message_queue_.push_back(MessageQueueEntry());
+  message_queue_.back().message = message;
+  if (dispatchers)
+    message_queue_.back().dispatchers.swap(*dispatchers);
   if (was_empty) {
     waiter_list_.AwakeWaitersForStateChange(SatisfiedFlags(),
                                             SatisfiableFlags());
   }
-
-  return MOJO_RESULT_OK;
 }
 
 void LocalMessagePipeEndpoint::CancelAllWaiters() {
   DCHECK(is_open_);
   waiter_list_.CancelAllWaiters();
 }
 
 // TODO(vtl): Support receiving handles.
 MojoResult LocalMessagePipeEndpoint::ReadMessage(
     void* bytes, uint32_t* num_bytes,
     uint32_t max_num_dispatchers,
     std::vector<scoped_refptr<Dispatcher> >* dispatchers,
     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 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();
+  MessageInTransit* const message = message_queue_.front().message;
   if (num_bytes)
     *num_bytes = message->data_size();
   if (message->data_size() <= max_bytes)
     memcpy(bytes, message->data(), message->data_size());
   else
     not_enough_space = true;
 
   if (!not_enough_space || (flags & MOJO_READ_MESSAGE_FLAG_MAY_DISCARD)) {
     message_queue_.pop_front();
-    message->Destroy();
 
     // Now it's empty, thus no longer readable.
     if (message_queue_.empty()) {
       // It's currently not possible to wait for non-readability, but we should
       // do the state change anyway.
       waiter_list_.AwakeWaitersForStateChange(SatisfiedFlags(),
                                               SatisfiableFlags());
     }
   }
 
@@ skipping 35 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