device/serial/serial_io_handler_posix.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef DEVICE_SERIAL_SERIAL_IO_HANDLER_POSIX_H_
   6 #define DEVICE_SERIAL_SERIAL_IO_HANDLER_POSIX_H_
   7
   8 #include "base/message_loop/message_loop.h"
   9 #include "base/single_thread_task_runner.h"
  10 #include "base/thread_task_runner_handle.h"
  11 #include "device/serial/serial_io_handler.h"
  12
  13 namespace device {
  14
  15 // Linux reports breaks and parity errors by inserting the sequence '\377\0x'
  16 // into the byte stream where 'x' is '\0' for a break and the corrupted byte for
  17 // a parity error.
  18 enum class ErrorDetectState { NO_ERROR, MARK_377_SEEN, MARK_0_SEEN };
  19
  20 class SerialIoHandlerPosix : public SerialIoHandler,
  21                              public base::MessageLoopForIO::Watcher {
  22  protected:
  23   // SerialIoHandler impl.
  24   void ReadImpl() override;
  25   void WriteImpl() override;
  26   void CancelReadImpl() override;
  27   void CancelWriteImpl() override;
  28   bool ConfigurePortImpl() override;
  29   bool Flush() const override;
  30   serial::DeviceControlSignalsPtr GetControlSignals() const override;
  31   bool SetControlSignals(
  32       const serial::HostControlSignals& control_signals) override;
  33   serial::ConnectionInfoPtr GetPortInfo() const override;
  34   bool SetBreak() override;
  35   bool ClearBreak() override;
  36   int CheckReceiveError(char* buffer,
  37                         int buffer_len,
  38                         int bytes_read,
  39                         bool& break_detected,
  40                         bool& parity_error_detected);
  41
  42  private:
  43   friend class SerialIoHandler;
  44   friend class SerialIoHandlerPosixTest;
  45
  46   SerialIoHandlerPosix(
  47       scoped_refptr<base::SingleThreadTaskRunner> file_thread_task_runner,
  48       scoped_refptr<base::SingleThreadTaskRunner> ui_thread_task_runner);
  49   ~SerialIoHandlerPosix() override;
  50
  51   // base::MessageLoopForIO::Watcher implementation.
  52   void OnFileCanWriteWithoutBlocking(int fd) override;
  53   void OnFileCanReadWithoutBlocking(int fd) override;
  54
  55   void EnsureWatchingReads();
  56   void EnsureWatchingWrites();
  57
  58   base::MessageLoopForIO::FileDescriptorWatcher file_read_watcher_;
  59   base::MessageLoopForIO::FileDescriptorWatcher file_write_watcher_;
  60
  61   // Flags indicating if the message loop is watching the device for IO events.
  62   bool is_watching_reads_;
  63   bool is_watching_writes_;
  64
  65   ErrorDetectState error_detect_state_;
  66   bool parity_check_enabled_;
  67   char chars_stashed_[2];
  68   int num_chars_stashed_;
  69
  70   DISALLOW_COPY_AND_ASSIGN(SerialIoHandlerPosix);
  71 };
  72
  73 }  // namespace device
  74
  75 #endif  // DEVICE_SERIAL_SERIAL_IO_HANDLER_POSIX_H_