bindings/python/sigrok/core/classes.py

   1 ##
   2 ## This file is part of the sigrok project.
   3 ##
   4 ## Copyright (C) 2013 Martin Ling <martin-sigrok@earth.li>
   5 ##
   6 ## This program is free software: you can redistribute it and/or modify
   7 ## it under the terms of the GNU General Public License as published by
   8 ## the Free Software Foundation, either version 3 of the License, or
   9 ## (at your option) any later version.
  10 ##
  11 ## This program is distributed in the hope that it will be useful,
  12 ## but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 ## GNU General Public License for more details.
  15 ##
  16 ## You should have received a copy of the GNU General Public License
  17 ## along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 ##
  19
  20 from functools import partial
  21 from fractions import Fraction
  22 from .lowlevel import *
  23 from . import lowlevel
  24 import itertools
  25
  26 __all__ = ['Error', 'Context', 'Driver', 'Device', 'Session', 'Packet']
  27
  28 class Error(Exception):
  29
  30     def __str__(self):
  31         return sr_strerror(self.args[0])
  32
  33 def check(result):
  34     if result != SR_OK:
  35         raise Error(result)
  36
  37 def config_key(name):
  38     if not name.lower() == name:
  39         raise AttributeError
  40     key_name = "SR_CONF_" + name.upper()
  41     return getattr(lowlevel, key_name)
  42
  43 def gvariant_to_python(value):
  44     type_string = g_variant_get_type_string(value)
  45     if type_string == 't':
  46         return g_variant_get_uint64(value)
  47     if type_string == 'b':
  48         return g_variant_get_bool(value)
  49     if type_string == 'd':
  50         return g_variant_get_double(value)
  51     if type_string == 's':
  52         return g_variant_get_string(value, None)
  53     if type_string == '(tt)':
  54         return Fraction(
  55             g_variant_get_uint64(g_variant_get_child_value(value, 0)),
  56             g_variant_get_uint64(g_variant_get_child_value(value, 1)))
  57     raise NotImplementedError(
  58         "Can't convert GVariant type '%s' to a Python type." % type_string)
  59
  60 def python_to_gvariant(value):
  61     if isinstance(value, int):
  62         return g_variant_new_uint64(value)
  63     if isinstance(value, bool):
  64         return g_variant_new_boolean(value)
  65     if isinstance(value, float):
  66         return g_variant_new_double(value)
  67     if isinstance(value, str):
  68         return g_variant_new_string(value)
  69     if isinstance(value, Fraction):
  70         array = new_gvariant_ptr_array(2)
  71         gvariant_ptr_array_setitem(array, 0, value.numerator)
  72         gvariant_ptr_array_setitem(array, 1, value.denominator)
  73         result = g_variant_new_tuple(array, 2)
  74         delete_gvariant_ptr_array(array)
  75         return result
  76     raise NotImplementedError(
  77         "Can't convert Python '%s' to a GVariant." % type(value))
  78
  79 def callback_wrapper(session, callback, device_ptr, packet_ptr):
  80     device = session.context._devices[int(device_ptr.this)]
  81     packet = Packet(session, packet_ptr)
  82     callback(device, packet)
  83
  84 class Context(object):
  85
  86     def __init__(self):
  87         context_ptr_ptr = new_sr_context_ptr_ptr()
  88         check(sr_init(context_ptr_ptr))
  89         self.struct = sr_context_ptr_ptr_value(context_ptr_ptr)
  90         self._drivers = None
  91         self._devices = {}
  92         self.session = None
  93
  94     def __del__(self):
  95         sr_exit(self.struct)
  96
  97     @property
  98     def drivers(self):
  99         if not self._drivers:
 100             self._drivers = {}
 101             driver_list = sr_driver_list()
 102             for i in itertools.count():
 103                 driver_ptr = sr_dev_driver_ptr_array_getitem(driver_list, i)
 104                 if driver_ptr:
 105                     self._drivers[driver_ptr.name] = Driver(self, driver_ptr)
 106                 else:
 107                     break
 108         return self._drivers
 109
 110 class Driver(object):
 111
 112     def __init__(self, context, struct):
 113         self.context = context
 114         self.struct = struct
 115         self._initialized = False
 116
 117     @property
 118     def name(self):
 119         return self.struct.name
 120
 121     def scan(self):
 122         if not self._initialized:
 123             check(sr_driver_init(self.context.struct, self.struct))
 124             self._initialized = True
 125         devices = []
 126         device_list = sr_driver_scan(self.struct, None)
 127         device_list_item = device_list
 128         while device_list_item:
 129             ptr = device_list_item.data
 130             device_ptr = gpointer_to_sr_dev_inst_ptr(ptr)
 131             devices.append(Device(self, device_ptr))
 132             device_list_item = device_list_item.next
 133         g_slist_free(device_list)
 134         return devices
 135
 136 class Device(object):
 137
 138     def __new__(cls, driver, struct):
 139         address = int(struct.this)
 140         if address not in driver.context._devices:
 141             device = super(Device, cls).__new__(cls, driver, struct)
 142             driver.context._devices[address] = device
 143         return driver.context._devices[address]
 144
 145     def __init__(self, driver, struct):
 146         self.driver = driver
 147         self.struct = struct
 148
 149     def __getattr__(self, name):
 150         key = config_key(name)
 151         data = new_gvariant_ptr_ptr()
 152         try:
 153             check(sr_config_get(self.driver.struct, key, data, self.struct))
 154         except Error as error:
 155             if error.errno == SR_ERR_ARG:
 156                 raise NotImplementedError(
 157                     "Device does not implement %s" % name)
 158             else:
 159                 raise AttributeError
 160         value = gvariant_ptr_ptr_value(data)
 161         return gvariant_to_python(value)
 162
 163     def __setattr__(self, name, value):
 164         try:
 165             key = config_key(name)
 166         except AttributeError:
 167             super(Device, self).__setattr__(name, value)
 168             return
 169         check(sr_config_set(self.struct, key, python_to_gvariant(value)))
 170
 171     @property
 172     def vendor(self):
 173         return self.struct.vendor
 174
 175     @property
 176     def model(self):
 177         return self.struct.model
 178
 179     @property
 180     def version(self):
 181         return self.struct.version
 182
 183 class Session(object):
 184
 185     def __init__(self, context):
 186         assert context.session is None
 187         self.context = context
 188         self.struct = sr_session_new()
 189         context.session = self
 190
 191     def __del__(self):
 192         check(sr_session_destroy())
 193
 194     def add_device(self, device):
 195         check(sr_session_dev_add(device.struct))
 196
 197     def add_callback(self, callback):
 198         wrapper = partial(callback_wrapper, self, callback)
 199         check(sr_session_datafeed_python_callback_add(wrapper))
 200
 201     def start(self):
 202         check(sr_session_start())
 203
 204     def run(self):
 205         check(sr_session_run())
 206
 207     def stop(self):
 208         check(sr_session_stop())
 209
 210 class Packet(object):
 211
 212     def __init__(self, session, struct):
 213         self.session = session
 214         self.struct = struct
 215         self._payload = None
 216
 217     @property
 218     def type(self):
 219         return self.struct.type
 220
 221     @property
 222     def payload(self):
 223         if self._payload is None:
 224             pointer = self.struct.payload
 225             if self.struct.type == SR_DF_LOGIC:
 226                 self._payload = Logic(self,
 227                     void_ptr_to_sr_datafeed_logic_ptr(pointer))
 228             else:
 229                 raise NotImplementedError(
 230                     "No Python mapping for packet type %ѕ" % self.struct.type)
 231         return self._payload
 232
 233 class Logic(object):
 234
 235     def __init__(self, packet, struct):
 236         self.packet = packet
 237         self.struct = struct
 238         self._data = None
 239
 240     @property
 241     def data(self):
 242         if self._data is None:
 243             self._data = cdata(self.struct.data, self.struct.length)
 244         return self._data
 245
 246 for symbol_name in dir(lowlevel):
 247     prefix = 'SR_DF_'
 248     if symbol_name.startswith(prefix):
 249         name = symbol_name[len(prefix):]
 250         setattr(Packet, name, getattr(lowlevel, symbol_name))