src/bindings/python/bt2/bt2/message_iterator.py

   1 # The MIT License (MIT)
   2 #
   3 # Copyright (c) 2017 Philippe Proulx <pproulx@efficios.com>
   4 #
   5 # Permission is hereby granted, free of charge, to any person obtaining a copy
   6 # of this software and associated documentation files (the "Software"), to deal
   7 # in the Software without restriction, including without limitation the rights
   8 # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   9 # copies of the Software, and to permit persons to whom the Software is
  10 # furnished to do so, subject to the following conditions:
  11 #
  12 # The above copyright notice and this permission notice shall be included in
  13 # all copies or substantial portions of the Software.
  14 #
  15 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17 # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  18 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  21 # THE SOFTWARE.
  22
  23 from bt2 import native_bt, object, utils
  24 from bt2 import message as bt2_message
  25 import collections.abc
  26 from bt2 import component as bt2_component
  27 from bt2 import stream as bt2_stream
  28 from bt2 import event_class as bt2_event_class
  29 from bt2 import packet as bt2_packet
  30 from bt2 import port as bt2_port
  31 from bt2 import clock_class as bt2_clock_class
  32 import bt2
  33
  34
  35 class _MessageIterator(collections.abc.Iterator):
  36     def __next__(self):
  37         raise NotImplementedError
  38
  39
  40 class _GenericMessageIterator(object._SharedObject, _MessageIterator):
  41     def __init__(self, ptr):
  42         self._current_msgs = []
  43         self._at = 0
  44         super().__init__(ptr)
  45
  46     def __next__(self):
  47         if len(self._current_msgs) == self._at:
  48             status, msgs = self._get_msg_range(self._ptr)
  49             utils._handle_func_status(
  50                 status, 'unexpected error: cannot advance the message iterator'
  51             )
  52             self._current_msgs = msgs
  53             self._at = 0
  54
  55         msg_ptr = self._current_msgs[self._at]
  56         self._at += 1
  57
  58         return bt2_message._create_from_ptr(msg_ptr)
  59
  60     @property
  61     def can_seek_beginning(self):
  62         res = self._can_seek_beginning(self._ptr)
  63         return res != 0
  64
  65     def seek_beginning(self):
  66         # Forget about buffered messages, they won't be valid after seeking..
  67         self._current_msgs.clear()
  68         self._at = 0
  69
  70         status = self._seek_beginning(self._ptr)
  71         utils._handle_func_status(status, 'cannot seek message iterator beginning')
  72
  73
  74 # This is created when a component wants to iterate on one of its input ports.
  75 class _UserComponentInputPortMessageIterator(_GenericMessageIterator):
  76     _get_msg_range = staticmethod(native_bt.bt2_self_component_port_input_get_msg_range)
  77     _get_ref = staticmethod(
  78         native_bt.self_component_port_input_message_iterator_get_ref
  79     )
  80     _put_ref = staticmethod(
  81         native_bt.self_component_port_input_message_iterator_put_ref
  82     )
  83     _can_seek_beginning = staticmethod(
  84         native_bt.self_component_port_input_message_iterator_can_seek_beginning
  85     )
  86     _seek_beginning = staticmethod(
  87         native_bt.self_component_port_input_message_iterator_seek_beginning
  88     )
  89
  90
  91 # This is created when the user wants to iterate on a component's output port,
  92 # from outside the graph.
  93 class _OutputPortMessageIterator(_GenericMessageIterator):
  94     _get_msg_range = staticmethod(native_bt.bt2_port_output_get_msg_range)
  95     _get_ref = staticmethod(native_bt.port_output_message_iterator_get_ref)
  96     _put_ref = staticmethod(native_bt.port_output_message_iterator_put_ref)
  97     _can_seek_beginning = staticmethod(
  98         native_bt.port_output_message_iterator_can_seek_beginning
  99     )
 100     _seek_beginning = staticmethod(
 101         native_bt.port_output_message_iterator_seek_beginning
 102     )
 103
 104
 105 # This is extended by the user to implement component classes in Python.  It
 106 # is created for a given output port when an input port message iterator is
 107 # created on the input port on the other side of the connection.  It is also
 108 # created when an output port message iterator is created on this output port.
 109 #
 110 # Its purpose is to feed the messages that should go out through this output
 111 # port.
 112 class _UserMessageIterator(_MessageIterator):
 113     def __new__(cls, ptr):
 114         # User iterator objects are always created by the native side,
 115         # that is, never instantiated directly by Python code.
 116         #
 117         # The native code calls this, then manually calls
 118         # self.__init__() without the `ptr` argument. The user has
 119         # access to self.component during this call, thanks to this
 120         # self._bt_ptr argument being set.
 121         #
 122         # self._bt_ptr is NOT owned by this object here, so there's nothing
 123         # to do in __del__().
 124         self = super().__new__(cls)
 125         self._bt_ptr = ptr
 126         return self
 127
 128     def _bt_init_from_native(self, self_output_port_ptr):
 129         self_output_port = bt2_port._create_self_from_ptr_and_get_ref(
 130             self_output_port_ptr, native_bt.PORT_TYPE_OUTPUT
 131         )
 132         self.__init__(self_output_port)
 133
 134     def __init__(self, output_port):
 135         pass
 136
 137     @property
 138     def _component(self):
 139         return native_bt.bt2_get_user_component_from_user_msg_iter(self._bt_ptr)
 140
 141     @property
 142     def addr(self):
 143         return int(self._bt_ptr)
 144
 145     @property
 146     def _is_interrupted(self):
 147         return bool(native_bt.self_message_iterator_is_interrupted(self._bt_ptr))
 148
 149     def _user_finalize(self):
 150         pass
 151
 152     def __next__(self):
 153         raise bt2.Stop
 154
 155     def _bt_next_from_native(self):
 156         # this can raise anything: it's catched by the native part
 157         try:
 158             msg = next(self)
 159         except StopIteration:
 160             raise bt2.Stop
 161         except:
 162             raise
 163
 164         utils._check_type(msg, bt2_message._Message)
 165
 166         # The reference we return will be given to the message array.
 167         # However, the `msg` Python object may stay alive, if the user has kept
 168         # a reference to it.  Acquire a new reference to account for that.
 169         msg._get_ref(msg._ptr)
 170         return int(msg._ptr)
 171
 172     @property
 173     def _bt_can_seek_beginning_from_native(self):
 174         # Here, we mimic the behavior of the C API:
 175         #
 176         # - If the iterator has a _user_can_seek_beginning attribute,
 177         #   read it and use that result.
 178         # - Otherwise, the presence or absence of a `_seek_beginning`
 179         #   method indicates whether the iterator can seek beginning.
 180         if hasattr(self, '_user_can_seek_beginning'):
 181             can_seek_beginning = self._user_can_seek_beginning
 182             utils._check_bool(can_seek_beginning)
 183             return can_seek_beginning
 184         else:
 185             return hasattr(self, '_user_seek_beginning')
 186
 187     def _bt_seek_beginning_from_native(self):
 188         self._user_seek_beginning()
 189
 190     def _create_input_port_message_iterator(self, input_port):
 191         utils._check_type(input_port, bt2_port._UserComponentInputPort)
 192
 193         msg_iter_ptr = native_bt.self_component_port_input_message_iterator_create_from_message_iterator(
 194             self._bt_ptr, input_port._ptr
 195         )
 196
 197         if msg_iter_ptr is None:
 198             raise bt2.CreationError('cannot create message iterator object')
 199
 200         return _UserComponentInputPortMessageIterator(msg_iter_ptr)
 201
 202     def _create_event_message(
 203         self, event_class, parent=None, default_clock_snapshot=None
 204     ):
 205         utils._check_type(event_class, bt2_event_class._EventClass)
 206
 207         if event_class.stream_class.supports_packets:
 208             utils._check_type(parent, bt2_packet._Packet)
 209         else:
 210             utils._check_type(parent, bt2_stream._Stream)
 211
 212         if default_clock_snapshot is not None:
 213             if event_class.stream_class.default_clock_class is None:
 214                 raise ValueError(
 215                     'event messages in this stream must not have a default clock snapshot'
 216                 )
 217
 218             utils._check_uint64(default_clock_snapshot)
 219
 220             if event_class.stream_class.supports_packets:
 221                 ptr = native_bt.message_event_create_with_packet_and_default_clock_snapshot(
 222                     self._bt_ptr, event_class._ptr, parent._ptr, default_clock_snapshot
 223                 )
 224             else:
 225                 ptr = native_bt.message_event_create_with_default_clock_snapshot(
 226                     self._bt_ptr, event_class._ptr, parent._ptr, default_clock_snapshot
 227                 )
 228         else:
 229             if event_class.stream_class.default_clock_class is not None:
 230                 raise ValueError(
 231                     'event messages in this stream must have a default clock snapshot'
 232                 )
 233
 234             if event_class.stream_class.supports_packets:
 235                 ptr = native_bt.message_event_create_with_packet(
 236                     self._bt_ptr, event_class._ptr, parent._ptr
 237                 )
 238             else:
 239                 ptr = native_bt.message_event_create(
 240                     self._bt_ptr, event_class._ptr, parent._ptr
 241                 )
 242
 243         if ptr is None:
 244             raise bt2._MemoryError('cannot create event message object')
 245
 246         return bt2_message._EventMessage(ptr)
 247
 248     def _create_message_iterator_inactivity_message(self, clock_class, clock_snapshot):
 249         utils._check_type(clock_class, bt2_clock_class._ClockClass)
 250         ptr = native_bt.message_message_iterator_inactivity_create(
 251             self._bt_ptr, clock_class._ptr, clock_snapshot
 252         )
 253
 254         if ptr is None:
 255             raise bt2._MemoryError('cannot create inactivity message object')
 256
 257         return bt2_message._MessageIteratorInactivityMessage(ptr)
 258
 259     def _create_stream_beginning_message(self, stream, default_clock_snapshot=None):
 260         utils._check_type(stream, bt2_stream._Stream)
 261
 262         ptr = native_bt.message_stream_beginning_create(self._bt_ptr, stream._ptr)
 263         if ptr is None:
 264             raise bt2._MemoryError('cannot create stream beginning message object')
 265
 266         msg = bt2_message._StreamBeginningMessage(ptr)
 267
 268         if default_clock_snapshot is not None:
 269             msg._default_clock_snapshot = default_clock_snapshot
 270
 271         return msg
 272
 273     def _create_stream_end_message(self, stream, default_clock_snapshot=None):
 274         utils._check_type(stream, bt2_stream._Stream)
 275
 276         ptr = native_bt.message_stream_end_create(self._bt_ptr, stream._ptr)
 277         if ptr is None:
 278             raise bt2._MemoryError('cannot create stream end message object')
 279
 280         msg = bt2_message._StreamEndMessage(ptr)
 281
 282         if default_clock_snapshot is not None:
 283             msg._default_clock_snapshot = default_clock_snapshot
 284
 285         return msg
 286
 287     def _create_packet_beginning_message(self, packet, default_clock_snapshot=None):
 288         utils._check_type(packet, bt2_packet._Packet)
 289
 290         if packet.stream.cls.packets_have_beginning_default_clock_snapshot:
 291             if default_clock_snapshot is None:
 292                 raise ValueError(
 293                     "packet beginning messages in this stream must have a default clock snapshot"
 294                 )
 295
 296             utils._check_uint64(default_clock_snapshot)
 297             ptr = native_bt.message_packet_beginning_create_with_default_clock_snapshot(
 298                 self._bt_ptr, packet._ptr, default_clock_snapshot
 299             )
 300         else:
 301             if default_clock_snapshot is not None:
 302                 raise ValueError(
 303                     "packet beginning messages in this stream must not have a default clock snapshot"
 304                 )
 305
 306             ptr = native_bt.message_packet_beginning_create(self._bt_ptr, packet._ptr)
 307
 308         if ptr is None:
 309             raise bt2._MemoryError('cannot create packet beginning message object')
 310
 311         return bt2_message._PacketBeginningMessage(ptr)
 312
 313     def _create_packet_end_message(self, packet, default_clock_snapshot=None):
 314         utils._check_type(packet, bt2_packet._Packet)
 315
 316         if packet.stream.cls.packets_have_end_default_clock_snapshot:
 317             if default_clock_snapshot is None:
 318                 raise ValueError(
 319                     "packet end messages in this stream must have a default clock snapshot"
 320                 )
 321
 322             utils._check_uint64(default_clock_snapshot)
 323             ptr = native_bt.message_packet_end_create_with_default_clock_snapshot(
 324                 self._bt_ptr, packet._ptr, default_clock_snapshot
 325             )
 326         else:
 327             if default_clock_snapshot is not None:
 328                 raise ValueError(
 329                     "packet end messages in this stream must not have a default clock snapshot"
 330                 )
 331
 332             ptr = native_bt.message_packet_end_create(self._bt_ptr, packet._ptr)
 333
 334         if ptr is None:
 335             raise bt2._MemoryError('cannot create packet end message object')
 336
 337         return bt2_message._PacketEndMessage(ptr)
 338
 339     def _create_discarded_events_message(
 340         self, stream, count=None, beg_clock_snapshot=None, end_clock_snapshot=None
 341     ):
 342         utils._check_type(stream, bt2_stream._Stream)
 343
 344         if not stream.cls.supports_discarded_events:
 345             raise ValueError('stream class does not support discarded events')
 346
 347         if stream.cls.discarded_events_have_default_clock_snapshots:
 348             if beg_clock_snapshot is None or end_clock_snapshot is None:
 349                 raise ValueError(
 350                     'discarded events have default clock snapshots for this stream class'
 351                 )
 352
 353             utils._check_uint64(beg_clock_snapshot)
 354             utils._check_uint64(end_clock_snapshot)
 355             ptr = native_bt.message_discarded_events_create_with_default_clock_snapshots(
 356                 self._bt_ptr, stream._ptr, beg_clock_snapshot, end_clock_snapshot
 357             )
 358         else:
 359             if beg_clock_snapshot is not None or end_clock_snapshot is not None:
 360                 raise ValueError(
 361                     'discarded events have no default clock snapshots for this stream class'
 362                 )
 363
 364             ptr = native_bt.message_discarded_events_create(self._bt_ptr, stream._ptr)
 365
 366         if ptr is None:
 367             raise bt2._MemoryError('cannot discarded events message object')
 368
 369         msg = bt2_message._DiscardedEventsMessage(ptr)
 370
 371         if count is not None:
 372             msg._count = count
 373
 374         return msg
 375
 376     def _create_discarded_packets_message(
 377         self, stream, count=None, beg_clock_snapshot=None, end_clock_snapshot=None
 378     ):
 379         utils._check_type(stream, bt2_stream._Stream)
 380
 381         if not stream.cls.supports_discarded_packets:
 382             raise ValueError('stream class does not support discarded packets')
 383
 384         if stream.cls.discarded_packets_have_default_clock_snapshots:
 385             if beg_clock_snapshot is None or end_clock_snapshot is None:
 386                 raise ValueError(
 387                     'discarded packets have default clock snapshots for this stream class'
 388                 )
 389
 390             utils._check_uint64(beg_clock_snapshot)
 391             utils._check_uint64(end_clock_snapshot)
 392             ptr = native_bt.message_discarded_packets_create_with_default_clock_snapshots(
 393                 self._bt_ptr, stream._ptr, beg_clock_snapshot, end_clock_snapshot
 394             )
 395         else:
 396             if beg_clock_snapshot is not None or end_clock_snapshot is not None:
 397                 raise ValueError(
 398                     'discarded packets have no default clock snapshots for this stream class'
 399                 )
 400
 401             ptr = native_bt.message_discarded_packets_create(self._bt_ptr, stream._ptr)
 402
 403         if ptr is None:
 404             raise bt2._MemoryError('cannot discarded packets message object')
 405
 406         msg = bt2_message._DiscardedPacketsMessage(ptr)
 407
 408         if count is not None:
 409             msg._count = count
 410
 411         return msg