# Copyright 2016 ARM Limited
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import os
import struct
from datetime import datetime
from collections import namedtuple
GENERAL_MODE = 0
GAMEPAD_MODE = 1
u16_struct = struct.Struct('<H')
u32_struct = struct.Struct('<I')
u64_struct = struct.Struct('<Q')
# See revent section in WA documentation for the detailed description of
# the recording format.
header_one_struct = struct.Struct('<6sH')
header_two_struct = struct.Struct('<H6x') # version 2 onwards
devid_struct = struct.Struct('<4H')
devinfo_struct = struct.Struct('<4s96s96s96sI')
absinfo_struct = struct.Struct('<7i')
event_struct = struct.Struct('<HqqHHi')
old_event_struct = struct.Struct("<i4xqqHHi") # prior to version 2
[docs]def read_struct(fh, struct_spec):
data = fh.read(struct_spec.size)
return struct_spec.unpack(data)
[docs]def read_string(fh):
length, = read_struct(fh, u32_struct)
str_struct = struct.Struct('<{}s'.format(length))
return read_struct(fh, str_struct)[0]
[docs]def count_bits(bitarr):
return sum(bin(b).count('1') for b in bitarr)
[docs]def is_set(bitarr, bit):
byte = bit // 8
bytebit = bit % 8
return bitarr[byte] & bytebit
absinfo = namedtuple('absinfo', 'ev_code value min max fuzz flat resolution')
[docs]class ReventEvent(object):
def __init__(self, fh, legacy=False):
if not legacy:
dev_id, ts_sec, ts_usec, type_, code, value = read_struct(fh, event_struct)
else:
dev_id, ts_sec, ts_usec, type_, code, value = read_struct(fh, old_event_struct)
self.device_id = dev_id
self.time = datetime.fromtimestamp(ts_sec + float(ts_usec) / 1000000)
self.type = type_
self.code = code
self.value = value
def __str__(self):
return 'InputEvent({})'.format(self.__dict__)
[docs]class ReventRecording(object):
"""
Represents a parsed revent recording. This contains input events and device
descriptions recorded by revent. Two parsing modes are supported. By
default, the recording will be parsed in the "streaming" mode. In this
mode, initial headers and device descritions are parsed on creation and an
open file handle to the recording is saved. Events will be read from the
file as they are being iterated over. In this mode, the entire recording is
never loaded into memory at once. The underlying file may be "released" by
calling ``close`` on the recroding, after which further iteration over the
events will not be possible (but would still be possible to access the file
description and header information).
The alternative is to load the entire recording on creation (in which case
the file handle will be closed once the recroding is loaded). This can be
enabled by specifying ``streaming=False``. This will make it faster to
subsequently iterate over the events, and also will not "hold" the file
open.
.. note:: When starting a new iteration over the events in streaming mode,
the postion in the open file will be automatically reset to the
beginning of the event stream. This means it's possible to iterate
over the events multiple times without having to re-open the
recording, however it is not possible to do so in parallel. If
parallel iteration is required, streaming should be disabled.
"""
@property
def duration(self):
if self._duration is None:
if self.stream:
events = self._iter_events()
try:
first = last = events.next()
except StopIteration:
self._duration = 0
else:
for last in events:
pass
self._duration = (last.time - first.time).total_seconds()
else: # not streaming
if not self._events:
self._duration = 0
self._duration = (self._events[-1].time -
self._events[0].time).total_seconds()
return self._duration
@property
def events(self):
if self.stream:
return self._iter_events()
else:
return self._events
def __init__(self, f, stream=True):
self.device_paths = []
self.gamepad_device = None
self.num_events = None
self.stream = stream
self._events = None
self._close_when_done = False
self._events_start = None
self._duration = None
if hasattr(f, 'name'): # file-like object
self.filepath = f.name
self.fh = f
else: # path to file
self.filepath = f
self.fh = open(self.filepath, 'rb')
if not self.stream:
self._close_when_done = True
try:
self._parse_header_and_devices(self.fh)
self._events_start = self.fh.tell()
if not self.stream:
self._events = [e for e in self._iter_events()]
finally:
if self._close_when_done:
self.close()
[docs] def close(self):
if self.fh is not None:
self.fh.close()
self.fh = None
self._events_start = None
def _parse_header_and_devices(self, fh):
magic, version = read_struct(fh, header_one_struct)
if magic != 'REVENT':
raise ValueError('{} does not appear to be an revent recording'.format(self.filepath))
self.version = version
if self.version == 2:
self.mode, = read_struct(fh, header_two_struct)
if self.mode == GENERAL_MODE:
self._read_devices(fh)
elif self.mode == GAMEPAD_MODE:
self._read_gamepad_info(fh)
else:
raise ValueError('Unexpected recording mode: {}'.format(self.mode))
self.num_events, = read_struct(fh, u64_struct)
elif 2 > self.version >= 0:
self.mode = GENERAL_MODE
self._read_devices(fh)
else:
raise ValueError('Invalid recording version: {}'.format(self.version))
def _read_devices(self, fh):
num_devices, = read_struct(fh, u32_struct)
for _ in xrange(num_devices):
self.device_paths.append(read_string(fh))
def _read_gamepad_info(self, fh):
self.gamepad_device = UinputDeviceInfo(fh)
self.device_paths.append('[GAMEPAD]')
def _iter_events(self):
if self.fh is None:
raise RuntimeError('Attempting to iterate over events of a closed recording')
self.fh.seek(self._events_start)
if self.version >= 2:
for _ in xrange(self.num_events):
yield ReventEvent(self.fh)
else:
file_size = os.path.getsize(self.filepath)
while self.fh.tell() < file_size:
yield ReventEvent(self.fh, legacy=True)
def __iter__(self):
for event in self.events:
yield event
def __enter__(self):
return self
def __exit__(self, *args):
self.close()
def __del__(self):
self.close()