src/tools/usb_gadget/mouse_gadget.py

   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 """Implementation of a USB HID mouse.
   6
   7 Two classes are provided by this module. The MouseFeature class implements
   8 the core functionality of a HID mouse and can be included in any HID gadget.
   9 The MouseGadget class implements an example mouse gadget.
  10 """
  11
  12 import struct
  13
  14 import hid_constants
  15 import hid_descriptors
  16 import hid_gadget
  17 import usb_constants
  18
  19
  20 class MouseFeature(hid_gadget.HidFeature):
  21   """HID feature implementation for a mouse.
  22
  23   REPORT_DESC provides an example HID report descriptor for a device including
  24   this functionality.
  25   """
  26
  27   REPORT_DESC = hid_descriptors.ReportDescriptor(
  28       hid_descriptors.UsagePage(0x01),  # Generic Desktop
  29       hid_descriptors.Usage(0x02),  # Mouse
  30       hid_descriptors.Collection(
  31           hid_constants.CollectionType.APPLICATION,
  32           hid_descriptors.Usage(0x01),  # Pointer
  33           hid_descriptors.Collection(
  34               hid_constants.CollectionType.PHYSICAL,
  35               hid_descriptors.UsagePage(0x09),  # Buttons
  36               hid_descriptors.UsageMinimum(1),
  37               hid_descriptors.UsageMaximum(3),
  38               hid_descriptors.LogicalMinimum(0, force_length=1),
  39               hid_descriptors.LogicalMaximum(1),
  40               hid_descriptors.ReportCount(3),
  41               hid_descriptors.ReportSize(1),
  42               hid_descriptors.Input(hid_descriptors.Data,
  43                                     hid_descriptors.Variable,
  44                                     hid_descriptors.Absolute),
  45               hid_descriptors.ReportCount(1),
  46               hid_descriptors.ReportSize(5),
  47               hid_descriptors.Input(hid_descriptors.Constant),
  48               hid_descriptors.UsagePage(0x01),  # Generic Desktop
  49               hid_descriptors.Usage(0x30),  # X
  50               hid_descriptors.Usage(0x31),  # Y
  51               hid_descriptors.LogicalMinimum(0x81),  # -127
  52               hid_descriptors.LogicalMaximum(127),
  53               hid_descriptors.ReportSize(8),
  54               hid_descriptors.ReportCount(2),
  55               hid_descriptors.Input(hid_descriptors.Data,
  56                                     hid_descriptors.Variable,
  57                                     hid_descriptors.Relative)
  58           )
  59       )
  60   )
  61
  62   def __init__(self):
  63     super(MouseFeature, self).__init__()
  64     self._buttons = 0
  65
  66   def ButtonDown(self, button):
  67     self._buttons |= button
  68     if self.IsConnected():
  69       self.SendReport(self.EncodeInputReport())
  70
  71   def ButtonUp(self, button):
  72     self._buttons &= ~button
  73     if self.IsConnected():
  74       self.SendReport(self.EncodeInputReport())
  75
  76   def Move(self, x_displacement, y_displacement):
  77     if self.IsConnected():
  78       self.SendReport(self.EncodeInputReport(x_displacement, y_displacement))
  79
  80   def EncodeInputReport(self, x_displacement=0, y_displacement=0):
  81     return struct.pack('Bbb', self._buttons, x_displacement, y_displacement)
  82
  83   def GetInputReport(self):
  84     """Construct an input report.
  85
  86     See Device Class Definition for Human Interface Devices (HID) Version 1.11
  87     Appendix B.2.
  88
  89     Returns:
  90       A packed input report.
  91     """
  92     return self.EncodeInputReport()
  93
  94
  95 class MouseGadget(hid_gadget.HidGadget):
  96   """USB gadget implementation of a HID mouse."""
  97
  98   def __init__(self):
  99     self._feature = MouseFeature()
 100     super(MouseGadget, self).__init__(
 101         report_desc=MouseFeature.REPORT_DESC,
 102         features={0: self._feature},
 103         packet_size=8,
 104         interval_ms=1,
 105         out_endpoint=False,
 106         vendor_id=usb_constants.VendorID.GOOGLE,
 107         product_id=usb_constants.ProductID.GOOGLE_MOUSE_GADGET,
 108         device_version=0x0100)
 109     self.AddStringDescriptor(1, 'Google Inc.')
 110     self.AddStringDescriptor(2, 'Mouse Gadget')
 111
 112   def ButtonDown(self, button):
 113     self._feature.ButtonDown(button)
 114
 115   def ButtonUp(self, button):
 116     self._feature.ButtonUp(button)
 117
 118   def Move(self, x_displacement, y_displacement):
 119     self._feature.Move(x_displacement, y_displacement)
 120
 121
 122 def RegisterHandlers():
 123   """Registers web request handlers with the application server."""
 124
 125   from tornado import web
 126
 127   class WebConfigureHandler(web.RequestHandler):
 128
 129     def post(self):
 130       gadget = MouseGadget()
 131       server.SwitchGadget(gadget)
 132
 133   class WebClickHandler(web.RequestHandler):
 134
 135     def post(self):
 136       BUTTONS = {
 137           '1': hid_constants.Mouse.BUTTON_1,
 138           '2': hid_constants.Mouse.BUTTON_2,
 139           '3': hid_constants.Mouse.BUTTON_3,
 140       }
 141
 142       button = BUTTONS[self.get_argument('button')]
 143       server.gadget.ButtonDown(button)
 144       server.gadget.ButtonUp(button)
 145
 146   class WebMoveHandler(web.RequestHandler):
 147
 148     def post(self):
 149       x = int(self.get_argument('x'))
 150       y = int(self.get_argument('y'))
 151       server.gadget.Move(x, y)
 152
 153   import server
 154   server.app.add_handlers('.*$', [
 155       (r'/mouse/configure', WebConfigureHandler),
 156       (r'/mouse/move', WebMoveHandler),
 157       (r'/mouse/click', WebClickHandler),
 158   ])