| # Copyright (c) 2012 The Chromium OS Authors. All rights reserved. |
| # Use of this source code is governed by a BSD-style license that can be |
| # found in the LICENSE file. |
| |
| """Keyboard device module to capture keyboard events.""" |
| |
| import fcntl |
| import os |
| import re |
| import sys |
| |
| sys.path.append('../../bin/input') |
| import input_device |
| |
| import mtb |
| |
| from linux_input import EV_KEY |
| |
| |
| class KeyboardDevice: |
| """A class about keyboard device properties.""" |
| |
| def __init__(self, device_node=None): |
| if device_node: |
| self.device_node = device_node |
| else: |
| self.device_node = input_device.get_device_node( |
| input_device.KEYBOARD_TYPES)) |
| self.system_device = self._non_blocking_open(self.device_node) |
| self._input_event = input_device.InputEvent() |
| |
| def __del__(self): |
| self.system_device.close() |
| |
| def exists(self): |
| """Indicate whether this device exists or not.""" |
| return bool(self.device_node) |
| |
| def _non_blocking_open(self, filename): |
| """Open the system file in the non-blocking mode.""" |
| fd = open(filename) |
| fcntl.fcntl(fd, fcntl.F_SETFL, os.O_NONBLOCK) |
| return fd |
| |
| def _non_blocking_read(self, fd): |
| """Non-blocking read on fd.""" |
| try: |
| self._input_event.read(fd) |
| return self._input_event |
| except Exception: |
| return None |
| |
| def get_key_press_event(self, fd): |
| """Read the keyboard device node to get the key press events.""" |
| event = True |
| # Read the device node continuously until either a key press event |
| # is got or there is no more events to read. |
| while event: |
| event = self._non_blocking_read(fd) |
| if event and event.type == EV_KEY and event.value == 1: |
| return event.code |
| return None |
