Mojo: More work towards sending message pipe handles over remote message pipes.

mojo/system/proxy_message_pipe_endpoint.h

 // 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.
 
 #ifndef MOJO_SYSTEM_PROXY_MESSAGE_PIPE_ENDPOINT_H_
 #define MOJO_SYSTEM_PROXY_MESSAGE_PIPE_ENDPOINT_H_
 
 #include <stdint.h>
 
 #include <deque>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "mojo/public/system/core.h"
 #include "mojo/system/message_in_transit.h"
 #include "mojo/system/message_pipe_endpoint.h"
 #include "mojo/system/system_impl_export.h"
 
 namespace mojo {
 namespace system {
 
 class Channel;
+class MessagePipe;
 
 // A |ProxyMessagePipeEndpoint| connects an end of a |MessagePipe| to a
 // |Channel|, over which it transmits and receives data (to/from another
 // |ProxyMessagePipeEndpoint|). So a |MessagePipe| with one endpoint local and
 // the other endpoint remote consists of a |LocalMessagePipeEndpoint| and a
 // |ProxyMessagePipeEndpoint|, with only the local endpoint being accessible via
 // a |MessagePipeDispatcher|.
 //
 // Like any |MessagePipeEndpoint|, a |ProxyMessagePipeEndpoint| is owned by a
 // |MessagePipe|.
@@ skipping 13 matching lines @@
   virtual void Close() OVERRIDE;
   virtual void OnPeerClose() OVERRIDE;
   virtual MojoResult EnqueueMessage(
       MessageInTransit* message,
       const std::vector<Dispatcher*>* dispatchers) OVERRIDE;
   virtual void Attach(scoped_refptr<Channel> channel,
                       MessageInTransit::EndpointId local_id) OVERRIDE;
   virtual void Run(MessageInTransit::EndpointId remote_id) OVERRIDE;
 
  private:
+  struct PreflightDispatcherInfo {
+    PreflightDispatcherInfo() : message_pipe(), port() {}
+
+    // For now, we only support sending message pipes, so this is simple.
+    MessagePipe* message_pipe;
+    unsigned port;
+  };
+
   bool is_attached() const {
     return !!channel_.get();
   }
 
   bool is_running() const {
     return remote_id_ != MessageInTransit::kInvalidEndpointId;
   }
 
-  MojoResult CanEnqueueDispatchers(const std::vector<Dispatcher*>* dispatchers);
+  // Checks that |dispatchers| will be able to be enqueued by
+  // |EnqueueMessageInternal()| (which then MUST be called if this succeeds).
+  // |dispatchers| must be non-null and nonempty; |preflight_dispatcher_infos|
+  // must be non-null and empty.
+  MojoResult PreflightDispatchers(
+      const std::vector<Dispatcher*>* dispatchers,
+      std::vector<PreflightDispatcherInfo>* preflight_dispatcher_infos);
   // |dispatchers| should be non-null only if it's nonempty, in which case the
-  // dispatchers should have been preflighted by |CanEnqueueDispatchers()|.
+  // dispatchers should have been preflighted by |PreflightDispatchers()|.
   void EnqueueMessageInternal(MessageInTransit* message,
                               const std::vector<Dispatcher*>* dispatchers);
 
 #ifdef NDEBUG
   void AssertConsistentState() const {}
 #else
   void AssertConsistentState() const;
 #endif
 
   // This should only be set if we're attached.
@@ skipping 16 matching lines @@
   // not ready to send them yet.
   std::deque<MessageInTransit*> paused_message_queue_;
 
   DISALLOW_COPY_AND_ASSIGN(ProxyMessagePipeEndpoint);
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_SYSTEM_PROXY_MESSAGE_PIPE_ENDPOINT_H_