Mojo: bindings connector

mojo/public/bindings/lib/connector.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_PUBLIC_BINDINGS_LIB_CONNECTOR_H_
+#define MOJO_PUBLIC_BINDINGS_LIB_CONNECTOR_H_
+
+#include <queue>
+
+#include "mojo/public/bindings/lib/bindings_support.h"
+#include "mojo/public/bindings/lib/message.h"
+#include "mojo/public/system/core.h"
+
+namespace mojo {
+
+// The Connector class is responsible for performing read/write operations on a
+// MessagePipe. It writes messages it receives through the MessageReceiver
+// interface that it subclasses, and it forwards messages it reads through the
+// MessageReceiver interface assigned as its incoming receiver.
+//
+// NOTE: MessagePipe I/O is non-blocking.
+//
+class Connector : public MessageReceiver {
+ public:
+  // The Connector does not take ownership of |message_pipe|.
+  // TODO(darin): Perhaps it should take ownership.
+  explicit Connector(Handle message_pipe);
+  virtual ~Connector();
+
+  // Sets the receiver to handle messages read from the message pipe.  The
+  // Connector will only read messages from the pipe if an incoming receiver
+  // has been set.
+  void SetIncomingReceiver(MessageReceiver* receiver);
+
+  // Returns true if an error was encountered while reading from or writing to
+  // the message pipe.
+  bool EncounteredError() const { return error_; }
+
+  // MessageReceiver implementation:
+  virtual bool Accept(Message* message) MOJO_OVERRIDE;
+
+ private:
+  class Callback : public BindingsSupport::AsyncWaitCallback {
+   public:
+    Callback();
+
+    void Cancel();
+    void SetOwnerToNotify(Connector* owner);
+    bool IsPending() const;
+
+    virtual void OnHandleReady(MojoResult result) MOJO_OVERRIDE;
+
+   private:
+    Connector* owner_;
+  };
+  friend class Callback;
+
+  void OnHandleReady(Callback* callback, MojoResult result);
+  void WaitToReadMore();
+  void WaitToWriteMore();
+  void ReadMore();
+  void WriteMore();
+
+  Handle message_pipe_;
+  MessageReceiver* incoming_receiver_;
+
+  Callback read_callback_;
+  Callback write_callback_;
+
+  bool error_;
+
+  std::queue<Message> write_queue_;
+};
+
+}  // namespace mojo
+
+#endif  // MOJO_PUBLIC_BINDINGS_LIB_CONNECTOR_H_