308 lines
11 KiB
Python
308 lines
11 KiB
Python
#
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# Base low-level functions used by the API proper.
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# Unlikely to be used directly unless you're expanding the API.
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#
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from struct import pack as _pack
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from binascii import hexlify as _hexlify
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_hex = lambda d: _hexlify(d).decode('ascii').upper()
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from .constants import ERROR_NAME
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from .exceptions import (NoReceiver as _NoReceiver,
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FeatureCallError as _FeatureCallError)
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from logging import getLogger
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_log = getLogger('LUR').getChild('base')
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del getLogger
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import hidapi as _hid
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#
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# These values are defined by the Logitech documentation.
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# Overstepping these boundaries will only produce log warnings.
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#
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"""Minimim lenght of a feature call packet."""
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_MIN_CALL_SIZE = 7
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"""Maximum lenght of a feature call packet."""
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_MAX_CALL_SIZE = 20
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"""Minimum size of a feature reply packet."""
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_MIN_REPLY_SIZE = _MIN_CALL_SIZE
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"""Maximum size of a feature reply packet."""
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_MAX_REPLY_SIZE = _MAX_CALL_SIZE
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"""Default timeout on read (in ms)."""
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DEFAULT_TIMEOUT = 1000
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#
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#
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#
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def _logdebug_hook(reply_code, devnumber, data):
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"""Default unhandled hook, logs the reply as DEBUG."""
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_log.warn("UNHANDLED [%02X %02X %s %s] (%s)", reply_code, devnumber, _hex(data[:2]), _hex(data[2:]), repr(data))
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"""The function that will be called on unhandled incoming events.
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The hook must be a function with the signature: ``_(int, int, str)``, where
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the parameters are: (reply_code, devnumber, data).
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This hook will only be called by the request() function, when it receives
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replies that do not match the requested feature call. As such, it is not
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suitable for intercepting broadcast events from the device (e.g. special
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keys being pressed, battery charge events, etc), at least not in a timely
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manner. However, these events *may* be delivered here if they happen while
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doing a feature call to the device.
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The default implementation logs the unhandled reply as DEBUG.
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"""
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unhandled_hook = _logdebug_hook
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#
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#
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#
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def list_receiver_devices():
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"""List all the Linux devices exposed by the UR attached to the machine."""
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# (Vendor ID, Product ID) = ('Logitech', 'Unifying Receiver')
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# interface 2 if the actual receiver interface
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return _hid.enumerate(0x046d, 0xc52b, 2)
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_COUNT_DEVICES_REQUEST = b'\x10\xFF\x81\x00\x00\x00\x00'
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def try_open(path):
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"""Checks if the given Linux device path points to the right UR device.
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:param path: the Linux device path.
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The UR physical device may expose multiple linux devices with the same
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interface, so we have to check for the right one. At this moment the only
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way to distinguish betheen them is to do a test ping on an invalid
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(attached) device number (i.e., 0), expecting a 'ping failed' reply.
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:returns: an open receiver handle if this is the right Linux device, or
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``None``.
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"""
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receiver_handle = _hid.open_path(path)
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if receiver_handle is None:
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# could be a file permissions issue (did you add the udev rules?)
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# in any case, unreachable
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_log.debug("[%s] open failed", path)
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return None
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_hid.write(receiver_handle, _COUNT_DEVICES_REQUEST)
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# if this is the right hidraw device, we'll receive a 'bad device' from the UR
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# otherwise, the read should produce nothing
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reply = _hid.read(receiver_handle, _MAX_REPLY_SIZE, DEFAULT_TIMEOUT)
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if reply:
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if reply[:5] == _COUNT_DEVICES_REQUEST[:5]:
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# 'device 0 unreachable' is the expected reply from a valid receiver handle
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_log.info("[%s] success: handle %X", path, receiver_handle)
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return receiver_handle
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# any other replies are ignored, and will assume this is the wrong Linux device
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if reply == b'\x01\x00\x00\x00\x00\x00\x00\x00':
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# no idea what this is, but it comes up occasionally
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_log.debug("[%s] %X mistery reply [%s]", path, receiver_handle, _hex(reply))
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else:
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_log.debug("[%s] %X unknown reply [%s]", path, receiver_handle, _hex(reply))
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else:
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_log.debug("[%s] %X no reply", path, receiver_handle)
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close(receiver_handle)
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def open():
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"""Opens the first Logitech Unifying Receiver found attached to the machine.
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:returns: An open file handle for the found receiver, or ``None``.
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"""
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for rawdevice in list_receiver_devices():
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_log.info("checking %s", rawdevice)
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receiver = try_open(rawdevice.path)
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if receiver:
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return receiver
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return None
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def close(handle):
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"""Closes a HID device handle."""
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if handle:
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try:
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_hid.close(handle)
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_log.info("closed receiver handle %X", handle)
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return True
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except:
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_log.exception("closing receiver handle %X", handle)
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return False
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def write(handle, devnumber, data):
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"""Writes some data to a certain device.
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:param handle: an open UR handle.
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:param devnumber: attached device number.
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:param data: data to send, up to 5 bytes.
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The first two (required) bytes of data must be the feature index for the
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device, and a function code for that feature.
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:raises NoReceiver: if the receiver is no longer available, i.e. has
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been physically removed from the machine, or the kernel driver has been
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unloaded. The handle will be closed automatically.
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"""
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assert _MIN_CALL_SIZE == 7
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assert _MAX_CALL_SIZE == 20
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# the data is padded to either 5 or 18 bytes
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wdata = _pack('!BB18s' if len(data) > 5 else '!BB5s', 0x10, devnumber, data)
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_log.debug("(%d) <= w[10 %02X %s %s]", devnumber, devnumber, _hex(wdata[2:4]), _hex(wdata[4:]))
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if not _hid.write(handle, wdata):
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_log.warn("(%d) write failed, assuming receiver %X no longer available", devnumber, handle)
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close(handle)
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raise _NoReceiver
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def read(handle, timeout=DEFAULT_TIMEOUT):
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"""Read some data from the receiver. Usually called after a write (feature
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call), to get the reply.
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:param handle: an open UR handle.
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:param timeout: read timeout on the UR handle.
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If any data was read in the given timeout, returns a tuple of
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(reply_code, devnumber, message data). The reply code is generally ``0x11``
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for a successful feature call, or ``0x10`` to indicate some error, e.g. the
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device is no longer available.
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:raises NoReceiver: if the receiver is no longer available, i.e. has
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been physically removed from the machine, or the kernel driver has been
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unloaded. The handle will be closed automatically.
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"""
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data = _hid.read(handle, _MAX_REPLY_SIZE, timeout)
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if data is None:
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_log.warn("(-) read failed, assuming receiver %X no longer available", handle)
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close(handle)
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raise _NoReceiver
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if data:
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if len(data) < _MIN_REPLY_SIZE:
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_log.warn("(%d) => r[%s] read packet too short: %d bytes", ord(data[1:2]), _hex(data), len(data))
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data += b'\x00' * (_MIN_REPLY_SIZE - len(data))
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if len(data) > _MAX_REPLY_SIZE:
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_log.warn("(%d) => r[%s] read packet too long: %d bytes", ord(data[1:2]), _hex(data), len(data))
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code = ord(data[:1])
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devnumber = ord(data[1:2])
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_log.debug("(%d) => r[%02X %02X %s %s]", devnumber, code, devnumber, _hex(data[2:4]), _hex(data[4:]))
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return code, devnumber, data[2:]
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# _l.log(_LOG_LEVEL, "(-) => r[]")
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_MAX_READ_TIMES = 3
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request_context = None
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from collections import namedtuple
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_DEFAULT_REQUEST_CONTEXT_CLASS = namedtuple('_DEFAULT_REQUEST_CONTEXT_CLASS', ['write', 'read', 'unhandled_hook'])
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_DEFAULT_REQUEST_CONTEXT = _DEFAULT_REQUEST_CONTEXT_CLASS(write=write, read=read, unhandled_hook=unhandled_hook)
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del namedtuple
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def request(handle, devnumber, feature_index_function, params=b'', features=None):
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"""Makes a feature call to a device and waits for a matching reply.
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This function will skip all incoming messages and events not related to the
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device we're requesting for, or the feature specified in the initial
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request; it will also wait for a matching reply indefinitely.
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:param handle: an open UR handle.
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:param devnumber: attached device number.
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:param feature_index_function: a two-byte string of (feature_index, feature_function).
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:param params: parameters for the feature call, 3 to 16 bytes.
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:param features: optional features array for the device, only used to fill
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the FeatureCallError exception if one occurs.
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:returns: the reply data packet, or ``None`` if the device is no longer
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available.
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:raisees FeatureCallError: if the feature call replied with an error.
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"""
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if type(params) == int:
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params = _pack('!B', params)
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_log.debug("(%d) request {%s} params [%s]", devnumber, _hex(feature_index_function), _hex(params))
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if len(feature_index_function) != 2:
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raise ValueError('invalid feature_index_function {%s}: it must be a two-byte string' % _hex(feature_index_function))
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if request_context is None or handle != request_context.handle:
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context = _DEFAULT_REQUEST_CONTEXT
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_unhandled = unhandled_hook
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else:
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context = request_context
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_unhandled = getattr(context, 'unhandled_hook')
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context.write(handle, devnumber, feature_index_function + params)
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read_times = _MAX_READ_TIMES
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while read_times > 0:
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divisor = (1 + _MAX_READ_TIMES - read_times)
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reply = context.read(handle, int(DEFAULT_TIMEOUT * (divisor + 1) / 2 / divisor))
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read_times -= 1
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if not reply:
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# keep waiting...
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continue
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reply_code, reply_devnumber, reply_data = reply
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if reply_devnumber != devnumber:
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# this message not for the device we're interested in
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# _l.log(_LOG_LEVEL, "(%d) request got reply for unexpected device %d: [%s]", devnumber, reply_devnumber, _hex(reply_data))
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# worst case scenario, this is a reply for a concurrent request
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# on this receiver
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if _unhandled:
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_unhandled(reply_code, reply_devnumber, reply_data)
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continue
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if reply_code == 0x10 and reply_data[:1] == b'\x8F' and reply_data[1:3] == feature_index_function:
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# device not present
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_log.debug("(%d) request ping failed on {%s} call: [%s]", devnumber, _hex(feature_index_function), _hex(reply_data))
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return None
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if reply_code == 0x10 and reply_data[:1] == b'\x8F':
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# device not present
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_log.debug("(%d) request ping failed: [%s]", devnumber, _hex(reply_data))
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return None
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if reply_code == 0x11 and reply_data[0] == b'\xFF' and reply_data[1:3] == feature_index_function:
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# the feature call returned with an error
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error_code = ord(reply_data[3])
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_log.warn("(%d) request feature call error %d = %s: %s", devnumber, error_code, ERROR_NAME[error_code], _hex(reply_data))
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feature_index = ord(feature_index_function[:1])
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feature_function = feature_index_function[1:2]
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feature = None if features is None else features[feature_index] if feature_index < len(features) else None
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raise _FeatureCallError(devnumber, feature, feature_index, feature_function, error_code, reply_data)
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if reply_code == 0x11 and reply_data[:2] == feature_index_function:
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# a matching reply
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# _log.debug("(%d) matched reply with feature-index-function [%s]", devnumber, _hex(reply_data[2:]))
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return reply_data[2:]
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if reply_code == 0x10 and devnumber == 0xFF and reply_data[:2] == feature_index_function:
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# direct calls to the receiver (device 0xFF) may also return successfully with reply code 0x10
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# _log.debug("(%d) matched reply with feature-index-function [%s]", devnumber, _hex(reply_data[2:]))
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return reply_data[2:]
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# _log.debug("(%d) unmatched reply {%s} (expected {%s})", devnumber, _hex(reply_data[:2]), _hex(feature_index_function))
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if _unhandled:
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_unhandled(reply_code, reply_devnumber, reply_data)
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