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// 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.
#include <memory>
#include <ostream>
#include "base/callback_forward.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/observer_list.h"
#include "base/optional.h"
#include "components/cryptauth/remote_device_ref.h"
namespace cryptauth {
class ConnectionObserver;
class WireMessage;
// Base class representing a connection with a remote device, which is a
// persistent bidirectional channel for sending and receiving wire messages.
class Connection {
enum class Status {
// Constructs a connection to the given |remote_device|.
explicit Connection(RemoteDeviceRef remote_device);
virtual ~Connection();
// Returns true iff the connection's status is CONNECTED.
bool IsConnected() const;
// Returns true iff the connection is currently sending a message.
bool is_sending_message() const { return is_sending_message_; }
// Sends a message to the remote device.
// |OnSendCompleted()| will be called for all observers upon completion with
// either success or failure.
void SendMessage(std::unique_ptr<WireMessage> message);
virtual void AddObserver(ConnectionObserver* observer);
virtual void RemoveObserver(ConnectionObserver* observer);
RemoteDeviceRef remote_device() const { return remote_device_; }
// Returns the RSSI of the connection; if no derived class overrides this
// function, base::nullopt is returned.
virtual void GetConnectionRssi(
base::OnceCallback<void(base::Optional<int32_t>)> callback);
// Abstract methods that subclasses should implement:
// Attempts to connect to the remote device if not already connected.
virtual void Connect() = 0;
// Disconnects from the remote device.
virtual void Disconnect() = 0;
// The bluetooth address of the connected device.
virtual std::string GetDeviceAddress() = 0;
Status status() const { return status_; }
// Sets the connection's status to |status|. If this is different from the
// previous status, notifies observers of the change in status.
// Virtual for testing.
virtual void SetStatus(Status status);
// Called after attempting to send bytes over the connection, whether the
// message was successfully sent or not.
// Virtual for testing.
virtual void OnDidSendMessage(const WireMessage& message, bool success);
// Called when bytes are read from the connection. There should not be a send
// in progress when this function is called.
// Virtual for testing.
virtual void OnBytesReceived(const std::string& bytes);
// Sends bytes over the connection. The implementing class should call
// OnDidSendMessage() once the send succeeds or fails. At most one send will
// be
// in progress.
virtual void SendMessageImpl(std::unique_ptr<WireMessage> message) = 0;
// Deserializes the |recieved_bytes_| and returns the resulting WireMessage,
// or NULL if the message is malformed. Sets |is_incomplete_message| to true
// if the |serialized_message| does not have enough data to parse the header,
// or if the message length encoded in the message header exceeds the size of
// the |serialized_message|. Exposed for testing.
virtual std::unique_ptr<WireMessage> DeserializeWireMessage(
bool* is_incomplete_message);
// Returns a string describing the associated device for logging purposes.
std::string GetDeviceInfoLogString();
// The remote device corresponding to this connection.
const RemoteDeviceRef remote_device_;
// The current status of the connection.
Status status_;
// The registered observers of the connection.
base::ObserverList<ConnectionObserver>::Unchecked observers_;
// A temporary buffer storing bytes received before a received message can be
// fully constructed.
std::string received_bytes_;
// Whether a message is currently in the process of being sent.
bool is_sending_message_;
std::ostream& operator<<(std::ostream& stream,
const Connection::Status& status);
} // namespace cryptauth