Creates a BattOrConnection for communicating with the BattOr

tools/battor_agent/battor_connection.h

+// Copyright 2015 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 TOOLS_BATTOR_AGENT_BATTOR_CONNECTION_H_
+#define TOOLS_BATTOR_AGENT_BATTOR_CONNECTION_H_
+
+#include <vector>
+
+#include "base/callback_forward.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "device/serial/serial.mojom.h"
+#include "tools/battor_agent/battor_error.h"
+#include "tools/battor_agent/battor_protocol_types.h"
+
+namespace device {
+class SerialIoHandler;
+}
+namespace net {
+class IOBuffer;
+}
+
+namespace battor {
+
+// A BattOrConnection is a wrapper around the serial connection to the BattOr
+// that handles conversion of a message to and from the byte-level BattOr
+// protocol.
+//
+// At a high-level, all BattOr messages consist of:
+//
+//   0x00               (1 byte start marker)
+//   uint8_t            (1 byte header indicating the message type)
+//   data               (message data, with 0x00s and 0x01s escaped with 0x02)
+//   0x01               (1 byte end marker)
+//
+// For a more in-depth description of the protocol, see http://bit.ly/1NvNVc3.
+class BattOrConnection : public base::SupportsWeakPtr<BattOrConnection> {
+ public:
+  // The listener interface that must be implemented in order to interact with
+  // the BattOrConnection.
+  class Listener {
+   public:
+    virtual void OnConnectionOpened(bool success) = 0;
+    virtual void OnBytesSent(bool success) = 0;
+    virtual void OnBytesRead(bool success,
+                             BattOrMessageType type,
+                             scoped_ptr<std::vector<char>> bytes) = 0;
+  };
+
+  // Constructs a new BattOrConnection. We use a WeakPtr for the listener
+  // because it's possible for the SerialIoHandler's connect, read, or write to
+  // complete after we've been destroyed, in which case we just want to cancel
+  BattOrConnection(
+      const std::string& path,
+      Listener* listener,
+      scoped_refptr<base::SingleThreadTaskRunner> file_thread_task_runner,
+      scoped_refptr<base::SingleThreadTaskRunner> ui_thread_task_runner);
+  virtual ~BattOrConnection();
+
+  // Initializes the serial connection and calls the listener's
+  // OnConnectionOpened() when complete. This function must be called before
+  // using the BattOrConnection.
+  void Open();
+  bool IsOpen();
+  // Closes the serial connection and releases any handles being held.
+  void Close();
+
+  // Sends the specified buffer over the serial connection and calls the
+  // listener's OnBytesSent() when complete. Note that bytes_to_send should not
+  // include the start, end, type, or escape bytes required by the BattOr
+  // protocol.
+  void SendBytes(BattOrMessageType type,
+                 const void* buffer,
+                 size_t bytes_to_send);
+
+  // Reads the specified number of bytes from the serial connection and calls
+  // the listener's OnBytesRead() when complete. Note that the number of bytes
+  // requested should not include the start, end, or type bytes required by the
+  // BattOr protocol, and that this method may issue multiple read read requests
+  // if the message contains escape characters.
+  void ReadBytes(size_t bytes_to_read);
+
+  // Flushes the serial connection to the BattOr.
+  void Flush();
+
+ protected:
+  // Overridden by the test to use a fake serial connection.
+  virtual scoped_refptr<device::SerialIoHandler> CreateIoHandler();
+
+  // IO handler capable of reading and writing from the serial connection.
+  scoped_refptr<device::SerialIoHandler> io_handler_;
+
+ private:
+  void OnOpened(bool success);
+
+  // Reads the specified number of additional bytes and adds them to the pending
+  // read buffer.
+  void ReadMoreBytes(size_t bytes_to_read);
+
+  // Internal callback for when bytes are read. This method may trigger
+  // additional reads if any newly read bytes are escape bytes.
+  void OnBytesRead(int bytes_read, device::serial::ReceiveError error);
+
+  // Internal callback for when bytes are sent.
+  void OnBytesSent(int bytes_sent, device::serial::SendError error);
+
+  // The path of the BattOr.
+  std::string path_;
+
+  // The listener receiving the results of the commands being executed.
+  Listener* listener_;
+
+  // All bytes that have been read since the user requested a read. If multiple
+  // reads are required due to the presence of escape bytes,
+  // pending_read_buffer_ grows with each read.
+  scoped_ptr<std::vector<char>> pending_read_buffer_;
+  // The bytes that were read in just the last read. If multiple reads are
+  // required due to the presence of escape bytes, last_read_buffer_ only
+  // contains the results of the last read.
+  scoped_refptr<net::IOBuffer> last_read_buffer_;
+  // The number of bytes that we requested in the last read.
+  size_t pending_read_length_;
+  // The number of escape bytes that have already been read.
+  size_t pending_read_escape_byte_count_;
+
+  // The total number of bytes that we're expecting to send.
+  size_t pending_write_length_;
+
+  // Threads needed for serial communication.
+  scoped_refptr<base::SingleThreadTaskRunner> file_thread_task_runner_;
+  scoped_refptr<base::SingleThreadTaskRunner> ui_thread_task_runner_;
+
+  DISALLOW_COPY_AND_ASSIGN(BattOrConnection);
+};
+
+}  // namespace battor
+
+#endif  // TOOLS_BATTOR_AGENT_BATTOR_CONNECTION_H_