[mojo-edk] Simplify multiprocess pipe bootstrap

mojo/edk/system/ports/node.h

 // Copyright 2016 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_EDK_SYSTEM_PORTS_NODE_H_
 #define MOJO_EDK_SYSTEM_PORTS_NODE_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 104 matching lines @@
   // notification may arrive synchronously (via PortStatusChanged() on the
   // delegate) if the peer is local to this Node.
   //
   // If send fails for any reason, |message| is left unchanged. On success,
   // ownserhip is transferred and |message| is reset.
   int SendMessage(const PortRef& port_ref, ScopedMessage* message);
 
   // Corresponding to NodeDelegate::ForwardMessage.
   int AcceptMessage(ScopedMessage message);
 
+  // Called to merge two ports with each other. If you have two independent
+  // port pairs A <=> B and C <=> D, the net result of merging B and C is a
+  // single connected port pair A <=> D.
+  //
+  // Note that the behavior of this operation is undefined if either port to be
+  // merged (B or C above) has ever been read from or written to directly, and
+  // this must ONLY be called on one side of the merge, though it doesn't matter
+  // which side.
+  //
+  // It is safe for the non-merged peers (A and D above) to be transferred,
+  // closed, and/or written to before, during, or after the merge.
+  int MergePorts(const PortRef& port_ref,
+                 const NodeName& destination_node_name,
+                 const PortName& destination_port_name);
+
   // Called to inform this node that communication with another node is lost
   // indefinitely. This triggers cleanup of ports bound to this node.
   int LostConnectionToNode(const NodeName& node_name);
 
  private:
   int OnUserMessage(ScopedMessage message);
   int OnPortAccepted(const PortName& port_name);
   int OnObserveProxy(const PortName& port_name,
                      const ObserveProxyEventData& event);
   int OnObserveProxyAck(const PortName& port_name, uint64_t last_sequence_num);
   int OnObserveClosure(const PortName& port_name, uint64_t last_sequence_num);
+  int OnMergePort(const PortName& port_name, const MergePortEventData& event);
 
   int AddPortWithName(const PortName& port_name,
                       const scoped_refptr<Port>& port);
   void ErasePort(const PortName& port_name);
   void ErasePort_Locked(const PortName& port_name);
   scoped_refptr<Port> GetPort(const PortName& port_name);
   scoped_refptr<Port> GetPort_Locked(const PortName& port_name);
 
   void WillSendPort_Locked(Port* port,
                            const NodeName& to_node_name,
                            PortName* port_name,
                            PortDescriptor* port_descriptor);
   int AcceptPort(const PortName& port_name,
                  const PortDescriptor& port_descriptor);
 
   int WillSendMessage_Locked(Port* port,
                              const PortName& port_name,
                              Message* message);
+  int BeginProxying_Locked(Port* port, const PortName& port_name);
   int ForwardMessages_Locked(Port* port, const PortName& port_name);
   void InitiateProxyRemoval_Locked(Port* port, const PortName& port_name);
   void MaybeRemoveProxy_Locked(Port* port, const PortName& port_name);
 
   ScopedMessage NewInternalMessage_Helper(const PortName& port_name,
                                           const EventType& type,
                                           const void* data,
                                           size_t num_data_bytes);
 
   ScopedMessage NewInternalMessage(const PortName& port_name,
@@ skipping 19 matching lines @@
   std::unordered_map<PortName, scoped_refptr<Port>> ports_;
 
   DISALLOW_COPY_AND_ASSIGN(Node);
 };
 
 }  // namespace ports
 }  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_PORTS_NODE_H_