[EasyUnlock] Port Connection class to native code.

components/proximity_auth/connection.h

+// Copyright 2014 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 COMPONENTS_PROXIMITY_AUTH_CONNECTION_H
+#define COMPONENTS_PROXIMITY_AUTH_CONNECTION_H
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/observer_list.h"
+#include "components/proximity_auth/remote_device.h"
+#include "net/base/io_buffer.h"
+
+namespace proximity_auth {
+
+class ConnectionObserver;
+class PermitMessage;
+
+// Base class representing a connection with a remote device, which is a
+// persistent bidirectional channel for sending and receiving permit messages.
+class Connection {
+ public:
+  enum Status {
+    DISCONNECTED,
+    IN_PROGRESS,
+    CONNECTED,
+  };
+
+  // Constructs a connection to the given |remote_device|.
+  explicit Connection(const RemoteDevice& remote_device);
+  ~Connection();
+
+  // Returns true iff the connection's status is CONNECTED.
+  bool IsConnected() const;
+
+  // Sends a message to the remote device.

[Tim Song, 2014/09/05 00:30:33]

Also make a note that OnSendCompleted will be called for all observers upon
completion with success or failure.

[Ilya Sherman, 2014/09/05 01:02:11]

Done.

+  void SendMessage(scoped_ptr<PermitMessage> message);
+
+  void AddObserver(ConnectionObserver* observer);
+  void RemoveObserver(ConnectionObserver* observer);
+
+  const RemoteDevice& remote_device() const { return remote_device_; }
+
+  // Abstract methods that subclasses should implement:
+
+  // Pauses or unpauses the handling of incoming messages.  Pausing allows the
+  // user of the connection to add or remove observers without missing messages.
+  virtual void SetPaused(bool paused) = 0;
+
+  // Attempts to connect to the remote device if not already connected.
+  virtual void Connect() = 0;
+
+  // Disconnects from the remote device.
+  virtual void Disconnect() = 0;
+
+ protected:
+  // Sets the connection's status to |status|. If this is different from the
+  // previous status, notifies observers of the change in status.
+  void SetStatus(Status status);
+
+  Status status() const { return status_; }
+
+  // Called after attempting to send bytes over the connection, whether the
+  // message was successfully sent or not.
+  void OnDidSendMessage(const PermitMessage& message, bool success);
+
+  // Called when bytes are read from the connection. There should not be a send
+  // in progress when this function is called.
+  void OnBytesReceived(scoped_refptr<net::IOBuffer> io_buffer,

[Tim Song, 2014/09/05 00:30:34]

Use vectors for the buffers so we don't have to think about the length.

[Ilya Sherman, 2014/09/05 01:02:11]

Used strings (see also my response to your related comment for the wire
message).

+                       int bytes_received);
+
+  // Cancels an in-progress connection.
+  virtual void CancelConnectionAttempt() = 0;

[Tim Song, 2014/09/05 00:30:34]

This can be public or just delete it since we don't actually use it anywhere in
the app.

[Ilya Sherman, 2014/09/05 01:02:11]

Done.

+
+  // Sends bytes over the connection. The implementing class should call
+  // OnSendCompleted() once the send succeeds or fails. At most one send will be
+  // in progress.
+  virtual void SendMessageImpl(scoped_ptr<PermitMessage> message) = 0;
+
+  // Returns |true| iff the |received_bytes_| are long enough to contain a
+  // complete permit message. Exposed for testing.
+  virtual bool HasReceivedCompleteMessage();
+
+  // Deserializes the |recieved_bytes_| and returns the resulting PermitMessage,
+  // or NULL if the message is malformed. Exposed for testing.
+  virtual scoped_ptr<PermitMessage> DeserializePermitMessage();

[Tim Song, 2014/09/05 00:30:33]

Are these functions temporarily exposed until the permit message is implemented?
It doesn't seem like they really need to be mocked.

[Ilya Sherman, 2014/09/05 01:02:11]

I'd prefer to test the connection code independently of the message parsing
code; so, no, I'm intending to leave these in place.

+
+  // Exposed for testing.
+  scoped_refptr<net::GrowableIOBuffer> received_bytes() {
+    return received_bytes_;
+  }
+
+ private:
+  // The remote device corresponding to this connection.
+  const RemoteDevice remote_device_;
+
+  // The current status of the connection.
+  Status status_;
+
+  // The registered observers of the connection.
+  ObserverList<ConnectionObserver> observers_;
+
+  // A temporary buffer storing bytes received before a received message can be
+  // fully constructed.
+  scoped_refptr<net::GrowableIOBuffer> received_bytes_;
+
+  // Whether a message is currently in the process of being sent.
+  bool is_sending_message_;
+
+  DISALLOW_COPY_AND_ASSIGN(Connection);
+};
+
+}  // namespace proximity_auth
+
+#endif  // COMPONENTS_PROXIMITY_AUTH_CONNECTION_H