text: // 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_MESSAGE_PIPE_ENDPOINT_H_
  #define MOJO_SYSTEM_MESSAGE_PIPE_ENDPOINT_H_
  
  #include <stdint.h>
  
  #include <vector>
  
  #include "base/basictypes.h"
  #include "base/memory/ref_counted.h"
  #include "base/memory/scoped_ptr.h"
  #include "mojo/public/c/system/core.h"
  #include "mojo/system/dispatcher.h"
  #include "mojo/system/message_in_transit.h"
  #include "mojo/system/system_impl_export.h"
  
  namespace mojo {
  namespace system {
  
  class Channel;
  class Waiter;
  
  // This is an interface to one of the ends of a message pipe, and is used by
  // |MessagePipe|. Its most important role is to provide a sink for messages
  // (i.e., a place where messages can be sent). It has a secondary role: When the
  // endpoint is local (i.e., in the current process), there'll be a dispatcher
  // corresponding to the endpoint. In that case, the implementation of
  // |MessagePipeEndpoint| also implements the functionality required by the
  // dispatcher, e.g., to read messages and to wait. Implementations of this class
  // are not thread-safe; instances are protected by |MesssagePipe|'s lock.
  class MOJO_SYSTEM_IMPL_EXPORT MessagePipeEndpoint {
   public:
    virtual ~MessagePipeEndpoint() {}
  
    enum Type {
      kTypeLocal,
      kTypeProxy
    };
    virtual Type GetType() const = 0;
  
    // All implementations must implement these.
    virtual void Close() = 0;
    virtual void OnPeerClose() = 0;
    // Implements |MessagePipe::EnqueueMessage()|. The major differences are that:
    //  a) Dispatchers have been vetted and cloned/attached to the message.
    //  b) At this point, we cannot report failure (if, e.g., a channel is torn
    //     down at this point, we should silently swallow the message).
    virtual void EnqueueMessage(scoped_ptr<MessageInTransit> message) = 0;
  
    // Implementations must override these if they represent a local endpoint,
    // i.e., one for which there's a |MessagePipeDispatcher| (and thus a handle).
    // An implementation for a proxy endpoint (for which there's no dispatcher)
    // needs not override these methods, since they should never be called.
    //
    // These methods implement the methods of the same name in |MessagePipe|,
    // though |MessagePipe|'s implementation may have to do a little more if the
    // operation involves both endpoints.
    virtual void CancelAllWaiters();
    virtual MojoResult ReadMessage(
        void* bytes, uint32_t* num_bytes,
        std::vector<scoped_refptr<Dispatcher> >* dispatchers,
        uint32_t* num_dispatchers,
        MojoReadMessageFlags flags);
    virtual MojoResult AddWaiter(Waiter* waiter,
                                 MojoWaitFlags flags,
                                 MojoResult wake_result);
    virtual void RemoveWaiter(Waiter* waiter);
  
    // Implementations must override these if they represent a proxy endpoint. An
    // implementation for a local endpoint needs not override these methods, since
    // they should never be called.
    virtual void Attach(scoped_refptr<Channel> channel,
                        MessageInTransit::EndpointId local_id);
    virtual void Run(MessageInTransit::EndpointId remote_id);
  
   protected:
    MessagePipeEndpoint() {}
  
   private:
    DISALLOW_COPY_AND_ASSIGN(MessagePipeEndpoint);
  };
  
  }  // namespace system
  }  // namespace mojo
  
  #endif  // MOJO_SYSTEM_MESSAGE_PIPE_ENDPOINT_H_
  