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Diffstat (limited to 'serial/serialwin32.py')
| -rw-r--r-- | serial/serialwin32.py | 477 |
1 files changed, 477 insertions, 0 deletions
diff --git a/serial/serialwin32.py b/serial/serialwin32.py new file mode 100644 index 0000000..e7da929 --- /dev/null +++ b/serial/serialwin32.py @@ -0,0 +1,477 @@ +#! python +# +# backend for Windows ("win32" incl. 32/64 bit support) +# +# (C) 2001-2020 Chris Liechti <cliechti@gmx.net> +# +# This file is part of pySerial. https://github.com/pyserial/pyserial +# SPDX-License-Identifier: BSD-3-Clause +# +# Initial patch to use ctypes by Giovanni Bajo <rasky@develer.com> + +from __future__ import absolute_import + +# pylint: disable=invalid-name,too-few-public-methods +import ctypes +import time +from serial import win32 + +import serial +from serial.serialutil import SerialBase, SerialException, to_bytes, PortNotOpenError, SerialTimeoutException + + +class Serial(SerialBase): + """Serial port implementation for Win32 based on ctypes.""" + + BAUDRATES = (50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800, + 9600, 19200, 38400, 57600, 115200) + + def __init__(self, *args, **kwargs): + self._port_handle = None + self._overlapped_read = None + self._overlapped_write = None + super(Serial, self).__init__(*args, **kwargs) + + def open(self): + """\ + Open port with current settings. This may throw a SerialException + if the port cannot be opened. + """ + if self._port is None: + raise SerialException("Port must be configured before it can be used.") + if self.is_open: + raise SerialException("Port is already open.") + # the "\\.\COMx" format is required for devices other than COM1-COM8 + # not all versions of windows seem to support this properly + # so that the first few ports are used with the DOS device name + port = self.name + try: + if port.upper().startswith('COM') and int(port[3:]) > 8: + port = '\\\\.\\' + port + except ValueError: + # for like COMnotanumber + pass + self._port_handle = win32.CreateFile( + port, + win32.GENERIC_READ | win32.GENERIC_WRITE, + 0, # exclusive access + None, # no security + win32.OPEN_EXISTING, + win32.FILE_ATTRIBUTE_NORMAL | win32.FILE_FLAG_OVERLAPPED, + 0) + if self._port_handle == win32.INVALID_HANDLE_VALUE: + self._port_handle = None # 'cause __del__ is called anyway + raise SerialException("could not open port {!r}: {!r}".format(self.portstr, ctypes.WinError())) + + try: + self._overlapped_read = win32.OVERLAPPED() + self._overlapped_read.hEvent = win32.CreateEvent(None, 1, 0, None) + self._overlapped_write = win32.OVERLAPPED() + #~ self._overlapped_write.hEvent = win32.CreateEvent(None, 1, 0, None) + self._overlapped_write.hEvent = win32.CreateEvent(None, 0, 0, None) + + # Setup a 4k buffer + win32.SetupComm(self._port_handle, 4096, 4096) + + # Save original timeout values: + self._orgTimeouts = win32.COMMTIMEOUTS() + win32.GetCommTimeouts(self._port_handle, ctypes.byref(self._orgTimeouts)) + + self._reconfigure_port() + + # Clear buffers: + # Remove anything that was there + win32.PurgeComm( + self._port_handle, + win32.PURGE_TXCLEAR | win32.PURGE_TXABORT | + win32.PURGE_RXCLEAR | win32.PURGE_RXABORT) + except: + try: + self._close() + except: + # ignore any exception when closing the port + # also to keep original exception that happened when setting up + pass + self._port_handle = None + raise + else: + self.is_open = True + + def _reconfigure_port(self): + """Set communication parameters on opened port.""" + if not self._port_handle: + raise SerialException("Can only operate on a valid port handle") + + # Set Windows timeout values + # timeouts is a tuple with the following items: + # (ReadIntervalTimeout,ReadTotalTimeoutMultiplier, + # ReadTotalTimeoutConstant,WriteTotalTimeoutMultiplier, + # WriteTotalTimeoutConstant) + timeouts = win32.COMMTIMEOUTS() + if self._timeout is None: + pass # default of all zeros is OK + elif self._timeout == 0: + timeouts.ReadIntervalTimeout = win32.MAXDWORD + else: + timeouts.ReadTotalTimeoutConstant = max(int(self._timeout * 1000), 1) + if self._timeout != 0 and self._inter_byte_timeout is not None: + timeouts.ReadIntervalTimeout = max(int(self._inter_byte_timeout * 1000), 1) + + if self._write_timeout is None: + pass + elif self._write_timeout == 0: + timeouts.WriteTotalTimeoutConstant = win32.MAXDWORD + else: + timeouts.WriteTotalTimeoutConstant = max(int(self._write_timeout * 1000), 1) + win32.SetCommTimeouts(self._port_handle, ctypes.byref(timeouts)) + + win32.SetCommMask(self._port_handle, win32.EV_ERR) + + # Setup the connection info. + # Get state and modify it: + comDCB = win32.DCB() + win32.GetCommState(self._port_handle, ctypes.byref(comDCB)) + comDCB.BaudRate = self._baudrate + + if self._bytesize == serial.FIVEBITS: + comDCB.ByteSize = 5 + elif self._bytesize == serial.SIXBITS: + comDCB.ByteSize = 6 + elif self._bytesize == serial.SEVENBITS: + comDCB.ByteSize = 7 + elif self._bytesize == serial.EIGHTBITS: + comDCB.ByteSize = 8 + else: + raise ValueError("Unsupported number of data bits: {!r}".format(self._bytesize)) + + if self._parity == serial.PARITY_NONE: + comDCB.Parity = win32.NOPARITY + comDCB.fParity = 0 # Disable Parity Check + elif self._parity == serial.PARITY_EVEN: + comDCB.Parity = win32.EVENPARITY + comDCB.fParity = 1 # Enable Parity Check + elif self._parity == serial.PARITY_ODD: + comDCB.Parity = win32.ODDPARITY + comDCB.fParity = 1 # Enable Parity Check + elif self._parity == serial.PARITY_MARK: + comDCB.Parity = win32.MARKPARITY + comDCB.fParity = 1 # Enable Parity Check + elif self._parity == serial.PARITY_SPACE: + comDCB.Parity = win32.SPACEPARITY + comDCB.fParity = 1 # Enable Parity Check + else: + raise ValueError("Unsupported parity mode: {!r}".format(self._parity)) + + if self._stopbits == serial.STOPBITS_ONE: + comDCB.StopBits = win32.ONESTOPBIT + elif self._stopbits == serial.STOPBITS_ONE_POINT_FIVE: + comDCB.StopBits = win32.ONE5STOPBITS + elif self._stopbits == serial.STOPBITS_TWO: + comDCB.StopBits = win32.TWOSTOPBITS + else: + raise ValueError("Unsupported number of stop bits: {!r}".format(self._stopbits)) + + comDCB.fBinary = 1 # Enable Binary Transmission + # Char. w/ Parity-Err are replaced with 0xff (if fErrorChar is set to TRUE) + if self._rs485_mode is None: + if self._rtscts: + comDCB.fRtsControl = win32.RTS_CONTROL_HANDSHAKE + else: + comDCB.fRtsControl = win32.RTS_CONTROL_ENABLE if self._rts_state else win32.RTS_CONTROL_DISABLE + comDCB.fOutxCtsFlow = self._rtscts + else: + # checks for unsupported settings + # XXX verify if platform really does not have a setting for those + if not self._rs485_mode.rts_level_for_tx: + raise ValueError( + 'Unsupported value for RS485Settings.rts_level_for_tx: {!r} (only True is allowed)'.format( + self._rs485_mode.rts_level_for_tx,)) + if self._rs485_mode.rts_level_for_rx: + raise ValueError( + 'Unsupported value for RS485Settings.rts_level_for_rx: {!r} (only False is allowed)'.format( + self._rs485_mode.rts_level_for_rx,)) + if self._rs485_mode.delay_before_tx is not None: + raise ValueError( + 'Unsupported value for RS485Settings.delay_before_tx: {!r} (only None is allowed)'.format( + self._rs485_mode.delay_before_tx,)) + if self._rs485_mode.delay_before_rx is not None: + raise ValueError( + 'Unsupported value for RS485Settings.delay_before_rx: {!r} (only None is allowed)'.format( + self._rs485_mode.delay_before_rx,)) + if self._rs485_mode.loopback: + raise ValueError( + 'Unsupported value for RS485Settings.loopback: {!r} (only False is allowed)'.format( + self._rs485_mode.loopback,)) + comDCB.fRtsControl = win32.RTS_CONTROL_TOGGLE + comDCB.fOutxCtsFlow = 0 + + if self._dsrdtr: + comDCB.fDtrControl = win32.DTR_CONTROL_HANDSHAKE + else: + comDCB.fDtrControl = win32.DTR_CONTROL_ENABLE if self._dtr_state else win32.DTR_CONTROL_DISABLE + comDCB.fOutxDsrFlow = self._dsrdtr + comDCB.fOutX = self._xonxoff + comDCB.fInX = self._xonxoff + comDCB.fNull = 0 + comDCB.fErrorChar = 0 + comDCB.fAbortOnError = 0 + comDCB.XonChar = serial.XON + comDCB.XoffChar = serial.XOFF + + if not win32.SetCommState(self._port_handle, ctypes.byref(comDCB)): + raise SerialException( + 'Cannot configure port, something went wrong. ' + 'Original message: {!r}'.format(ctypes.WinError())) + + #~ def __del__(self): + #~ self.close() + + def _close(self): + """internal close port helper""" + if self._port_handle is not None: + # Restore original timeout values: + win32.SetCommTimeouts(self._port_handle, self._orgTimeouts) + if self._overlapped_read is not None: + self.cancel_read() + win32.CloseHandle(self._overlapped_read.hEvent) + self._overlapped_read = None + if self._overlapped_write is not None: + self.cancel_write() + win32.CloseHandle(self._overlapped_write.hEvent) + self._overlapped_write = None + win32.CloseHandle(self._port_handle) + self._port_handle = None + + def close(self): + """Close port""" + if self.is_open: + self._close() + self.is_open = False + + # - - - - - - - - - - - - - - - - - - - - - - - - + + @property + def in_waiting(self): + """Return the number of bytes currently in the input buffer.""" + flags = win32.DWORD() + comstat = win32.COMSTAT() + if not win32.ClearCommError(self._port_handle, ctypes.byref(flags), ctypes.byref(comstat)): + raise SerialException("ClearCommError failed ({!r})".format(ctypes.WinError())) + return comstat.cbInQue + + def read(self, size=1): + """\ + Read size bytes from the serial port. If a timeout is set it may + return less characters as requested. With no timeout it will block + until the requested number of bytes is read. + """ + if not self.is_open: + raise PortNotOpenError() + if size > 0: + win32.ResetEvent(self._overlapped_read.hEvent) + flags = win32.DWORD() + comstat = win32.COMSTAT() + if not win32.ClearCommError(self._port_handle, ctypes.byref(flags), ctypes.byref(comstat)): + raise SerialException("ClearCommError failed ({!r})".format(ctypes.WinError())) + n = min(comstat.cbInQue, size) if self.timeout == 0 else size + if n > 0: + buf = ctypes.create_string_buffer(n) + rc = win32.DWORD() + read_ok = win32.ReadFile( + self._port_handle, + buf, + n, + ctypes.byref(rc), + ctypes.byref(self._overlapped_read)) + if not read_ok and win32.GetLastError() not in (win32.ERROR_SUCCESS, win32.ERROR_IO_PENDING): + raise SerialException("ReadFile failed ({!r})".format(ctypes.WinError())) + result_ok = win32.GetOverlappedResult( + self._port_handle, + ctypes.byref(self._overlapped_read), + ctypes.byref(rc), + True) + if not result_ok: + if win32.GetLastError() != win32.ERROR_OPERATION_ABORTED: + raise SerialException("GetOverlappedResult failed ({!r})".format(ctypes.WinError())) + read = buf.raw[:rc.value] + else: + read = bytes() + else: + read = bytes() + return bytes(read) + + def write(self, data): + """Output the given byte string over the serial port.""" + if not self.is_open: + raise PortNotOpenError() + #~ if not isinstance(data, (bytes, bytearray)): + #~ raise TypeError('expected %s or bytearray, got %s' % (bytes, type(data))) + # convert data (needed in case of memoryview instance: Py 3.1 io lib), ctypes doesn't like memoryview + data = to_bytes(data) + if data: + #~ win32event.ResetEvent(self._overlapped_write.hEvent) + n = win32.DWORD() + success = win32.WriteFile(self._port_handle, data, len(data), ctypes.byref(n), self._overlapped_write) + if self._write_timeout != 0: # if blocking (None) or w/ write timeout (>0) + if not success and win32.GetLastError() not in (win32.ERROR_SUCCESS, win32.ERROR_IO_PENDING): + raise SerialException("WriteFile failed ({!r})".format(ctypes.WinError())) + + # Wait for the write to complete. + #~ win32.WaitForSingleObject(self._overlapped_write.hEvent, win32.INFINITE) + win32.GetOverlappedResult(self._port_handle, self._overlapped_write, ctypes.byref(n), True) + if win32.GetLastError() == win32.ERROR_OPERATION_ABORTED: + return n.value # canceled IO is no error + if n.value != len(data): + raise SerialTimeoutException('Write timeout') + return n.value + else: + errorcode = win32.ERROR_SUCCESS if success else win32.GetLastError() + if errorcode in (win32.ERROR_INVALID_USER_BUFFER, win32.ERROR_NOT_ENOUGH_MEMORY, + win32.ERROR_OPERATION_ABORTED): + return 0 + elif errorcode in (win32.ERROR_SUCCESS, win32.ERROR_IO_PENDING): + # no info on true length provided by OS function in async mode + return len(data) + else: + raise SerialException("WriteFile failed ({!r})".format(ctypes.WinError())) + else: + return 0 + + def flush(self): + """\ + Flush of file like objects. In this case, wait until all data + is written. + """ + while self.out_waiting: + time.sleep(0.05) + # XXX could also use WaitCommEvent with mask EV_TXEMPTY, but it would + # require overlapped IO and it's also only possible to set a single mask + # on the port--- + + def reset_input_buffer(self): + """Clear input buffer, discarding all that is in the buffer.""" + if not self.is_open: + raise PortNotOpenError() + win32.PurgeComm(self._port_handle, win32.PURGE_RXCLEAR | win32.PURGE_RXABORT) + + def reset_output_buffer(self): + """\ + Clear output buffer, aborting the current output and discarding all + that is in the buffer. + """ + if not self.is_open: + raise PortNotOpenError() + win32.PurgeComm(self._port_handle, win32.PURGE_TXCLEAR | win32.PURGE_TXABORT) + + def _update_break_state(self): + """Set break: Controls TXD. When active, to transmitting is possible.""" + if not self.is_open: + raise PortNotOpenError() + if self._break_state: + win32.SetCommBreak(self._port_handle) + else: + win32.ClearCommBreak(self._port_handle) + + def _update_rts_state(self): + """Set terminal status line: Request To Send""" + if self._rts_state: + win32.EscapeCommFunction(self._port_handle, win32.SETRTS) + else: + win32.EscapeCommFunction(self._port_handle, win32.CLRRTS) + + def _update_dtr_state(self): + """Set terminal status line: Data Terminal Ready""" + if self._dtr_state: + win32.EscapeCommFunction(self._port_handle, win32.SETDTR) + else: + win32.EscapeCommFunction(self._port_handle, win32.CLRDTR) + + def _GetCommModemStatus(self): + if not self.is_open: + raise PortNotOpenError() + stat = win32.DWORD() + win32.GetCommModemStatus(self._port_handle, ctypes.byref(stat)) + return stat.value + + @property + def cts(self): + """Read terminal status line: Clear To Send""" + return win32.MS_CTS_ON & self._GetCommModemStatus() != 0 + + @property + def dsr(self): + """Read terminal status line: Data Set Ready""" + return win32.MS_DSR_ON & self._GetCommModemStatus() != 0 + + @property + def ri(self): + """Read terminal status line: Ring Indicator""" + return win32.MS_RING_ON & self._GetCommModemStatus() != 0 + + @property + def cd(self): + """Read terminal status line: Carrier Detect""" + return win32.MS_RLSD_ON & self._GetCommModemStatus() != 0 + + # - - platform specific - - - - + + def set_buffer_size(self, rx_size=4096, tx_size=None): + """\ + Recommend a buffer size to the driver (device driver can ignore this + value). Must be called after the port is opened. + """ + if tx_size is None: + tx_size = rx_size + win32.SetupComm(self._port_handle, rx_size, tx_size) + + def set_output_flow_control(self, enable=True): + """\ + Manually control flow - when software flow control is enabled. + This will do the same as if XON (true) or XOFF (false) are received + from the other device and control the transmission accordingly. + WARNING: this function is not portable to different platforms! + """ + if not self.is_open: + raise PortNotOpenError() + if enable: + win32.EscapeCommFunction(self._port_handle, win32.SETXON) + else: + win32.EscapeCommFunction(self._port_handle, win32.SETXOFF) + + @property + def out_waiting(self): + """Return how many bytes the in the outgoing buffer""" + flags = win32.DWORD() + comstat = win32.COMSTAT() + if not win32.ClearCommError(self._port_handle, ctypes.byref(flags), ctypes.byref(comstat)): + raise SerialException("ClearCommError failed ({!r})".format(ctypes.WinError())) + return comstat.cbOutQue + + def _cancel_overlapped_io(self, overlapped): + """Cancel a blocking read operation, may be called from other thread""" + # check if read operation is pending + rc = win32.DWORD() + err = win32.GetOverlappedResult( + self._port_handle, + ctypes.byref(overlapped), + ctypes.byref(rc), + False) + if not err and win32.GetLastError() in (win32.ERROR_IO_PENDING, win32.ERROR_IO_INCOMPLETE): + # cancel, ignoring any errors (e.g. it may just have finished on its own) + win32.CancelIoEx(self._port_handle, overlapped) + + def cancel_read(self): + """Cancel a blocking read operation, may be called from other thread""" + self._cancel_overlapped_io(self._overlapped_read) + + def cancel_write(self): + """Cancel a blocking write operation, may be called from other thread""" + self._cancel_overlapped_io(self._overlapped_write) + + @SerialBase.exclusive.setter + def exclusive(self, exclusive): + """Change the exclusive access setting.""" + if exclusive is not None and not exclusive: + raise ValueError('win32 only supports exclusive access (not: {})'.format(exclusive)) + else: + serial.SerialBase.exclusive.__set__(self, exclusive) |