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 import bt2.message
  25 import collections.abc
  26 import bt2.component
  27 import bt2
  28
  29
  30 class _MessageIterator(collections.abc.Iterator):
  31     def __next__(self):
  32         raise NotImplementedError
  33
  34
  35 class _GenericMessageIterator(object._SharedObject, _MessageIterator):
  36     def __init__(self, ptr):
  37             self._current_msgs = []
  38             self._at = 0
  39             super().__init__(ptr)
  40
  41     def _handle_status(self, status, gen_error_msg):
  42         if status == native_bt.MESSAGE_ITERATOR_STATUS_AGAIN:
  43             raise bt2.TryAgain
  44         elif status == native_bt.MESSAGE_ITERATOR_STATUS_END:
  45             raise bt2.Stop
  46         elif status < 0:
  47             raise bt2.Error(gen_error_msg)
  48
  49     def __next__(self):
  50         if len(self._current_msgs) == self._at:
  51             status, msgs = self._get_msg_range(self._ptr)
  52             self._handle_status(status,
  53                                 'unexpected error: cannot advance the message iterator')
  54             self._current_msgs = msgs
  55             self._at = 0
  56
  57         msg_ptr = self._current_msgs[self._at]
  58         self._at += 1
  59
  60         return bt2.message._create_from_ptr(msg_ptr)
  61
  62     @property
  63     def can_seek_beginning(self):
  64         res = self._can_seek_beginning(self._ptr)
  65         return res != 0
  66
  67     def seek_beginning(self):
  68         # Forget about buffered messages, they won't be valid after seeking..
  69         self._current_msgs.clear()
  70         self._at = 0
  71
  72         status = self._seek_beginning(self._ptr)
  73         self._handle_status(status, 'cannot seek message iterator beginning')
  74
  75
  76 # This is created when a component wants to iterate on one of its input ports.
  77 class _UserComponentInputPortMessageIterator(_GenericMessageIterator):
  78     _get_msg_range = staticmethod(native_bt.py3_self_component_port_input_get_msg_range)
  79     _get_ref = staticmethod(native_bt.self_component_port_input_message_iterator_get_ref)
  80     _put_ref = staticmethod(native_bt.self_component_port_input_message_iterator_put_ref)
  81     _can_seek_beginning = staticmethod(native_bt.self_component_port_input_message_iterator_can_seek_beginning)
  82     _seek_beginning = staticmethod(native_bt.self_component_port_input_message_iterator_seek_beginning)
  83
  84
  85 # This is created when the user wants to iterate on a component's output port,
  86 # from outside the graph.
  87 class _OutputPortMessageIterator(_GenericMessageIterator):
  88     _get_msg_range = staticmethod(native_bt.py3_port_output_get_msg_range)
  89     _get_ref = staticmethod(native_bt.port_output_message_iterator_get_ref)
  90     _put_ref = staticmethod(native_bt.port_output_message_iterator_put_ref)
  91     _can_seek_beginning = staticmethod(native_bt.port_output_message_iterator_can_seek_beginning)
  92     _seek_beginning = staticmethod(native_bt.port_output_message_iterator_seek_beginning)
  93
  94
  95 # This is extended by the user to implement component classes in Python.  It
  96 # is created for a given output port when an input port message iterator is
  97 # created on the input port on the other side of the connection.  It is also
  98 # created when an output port message iterator is created on this output port.
  99 #
 100 # Its purpose is to feed the messages that should go out through this output
 101 # port.
 102 class _UserMessageIterator(_MessageIterator):
 103     def __new__(cls, ptr):
 104         # User iterator objects are always created by the native side,
 105         # that is, never instantiated directly by Python code.
 106         #
 107         # The native code calls this, then manually calls
 108         # self.__init__() without the `ptr` argument. The user has
 109         # access to self.component during this call, thanks to this
 110         # self._ptr argument being set.
 111         #
 112         # self._ptr is NOT owned by this object here, so there's nothing
 113         # to do in __del__().
 114         self = super().__new__(cls)
 115         self._ptr = ptr
 116         return self
 117
 118     def _init_from_native(self, self_output_port_ptr):
 119         self_output_port = bt2.port._create_self_from_ptr_and_get_ref(
 120             self_output_port_ptr, native_bt.PORT_TYPE_OUTPUT)
 121         self.__init__(self_output_port)
 122
 123     def __init__(self, output_port):
 124         pass
 125
 126     @property
 127     def _component(self):
 128         return native_bt.py3_get_user_component_from_user_msg_iter(self._ptr)
 129
 130     @property
 131     def addr(self):
 132         return int(self._ptr)
 133
 134     def _finalize(self):
 135         pass
 136
 137     def __next__(self):
 138         raise bt2.Stop
 139
 140     def _next_from_native(self):
 141         # this can raise anything: it's catched by the native part
 142         try:
 143             msg = next(self)
 144         except StopIteration:
 145             raise bt2.Stop
 146         except:
 147             raise
 148
 149         utils._check_type(msg, bt2.message._Message)
 150
 151         # The reference we return will be given to the message array.
 152         # However, the `msg` Python object may stay alive, if the user has kept
 153         # a reference to it.  Acquire a new reference to account for that.
 154         msg._get_ref(msg._ptr)
 155         return int(msg._ptr)
 156
 157     @property
 158     def _can_seek_beginning_from_native(self):
 159         # Here, we mimic the behavior of the C API:
 160         #
 161         # - If the iterator has a _can_seek_beginning attribute, read it and use
 162         #   that result.
 163         # - Otherwise, the presence or absence of a `_seek_beginning`
 164         #   method indicates whether the iterator can seek beginning.
 165         if hasattr(self, '_can_seek_beginning'):
 166             can_seek_beginning = self._can_seek_beginning
 167             utils._check_bool(can_seek_beginning)
 168             return can_seek_beginning
 169         else:
 170             return hasattr(self, '_seek_beginning')
 171
 172     def _seek_beginning_from_native(self):
 173         self._seek_beginning()
 174
 175     def _create_event_message(self, event_class, packet, default_clock_snapshot=None):
 176         utils._check_type(event_class, bt2.event_class._EventClass)
 177         utils._check_type(packet, bt2.packet._Packet)
 178
 179         if default_clock_snapshot is not None:
 180             if event_class.stream_class.default_clock_class is None:
 181                 raise ValueError('event messages in this stream must not have a default clock snapshot')
 182
 183             utils._check_uint64(default_clock_snapshot)
 184             ptr = native_bt.message_event_create_with_default_clock_snapshot(
 185                 self._ptr, event_class._ptr, packet._ptr, default_clock_snapshot)
 186         else:
 187             if event_class.stream_class.default_clock_class is not None:
 188                 raise ValueError('event messages in this stream must have a default clock snapshot')
 189
 190             ptr = native_bt.message_event_create(
 191                 self._ptr, event_class._ptr, packet._ptr)
 192
 193         if ptr is None:
 194             raise bt2.CreationError('cannot create event message object')
 195
 196         return bt2.message._EventMessage(ptr)
 197
 198     def _create_message_iterator_inactivity_message(self, clock_class, clock_snapshot):
 199         utils._check_type(clock_class, bt2.clock_class._ClockClass)
 200         ptr = native_bt.message_message_iterator_inactivity_create(
 201             self._ptr, clock_class._ptr, clock_snapshot)
 202
 203         if ptr is None:
 204             raise bt2.CreationError('cannot create inactivity message object')
 205
 206         return bt2.message._MessageIteratorInactivityMessage(ptr)
 207
 208     _unknown_clock_snapshot = bt2.message._StreamActivityMessageUnknownClockSnapshot()
 209     _infinite_clock_snapshot = bt2.message._StreamActivityMessageInfiniteClockSnapshot()
 210
 211     @staticmethod
 212     def _validate_stream_activity_message_default_clock_snapshot(stream, default_cs):
 213         isinst_infinite = isinstance(default_cs, bt2.message._StreamActivityMessageInfiniteClockSnapshot)
 214         isinst_unknown = isinstance(default_cs, bt2.message._StreamActivityMessageUnknownClockSnapshot)
 215
 216         if utils._is_uint64(default_cs):
 217             pass
 218         elif isinst_infinite or isinst_unknown:
 219             if default_cs is not _UserMessageIterator._unknown_clock_snapshot and default_cs is not _UserMessageIterator._infinite_clock_snapshot:
 220                 raise ValueError('unexpected value for default clock snapshot')
 221         else:
 222             raise TypeError("unexpected type '{}' for default clock snapshot".format(default_cs.__class__.__name__))
 223
 224         if stream.cls.default_clock_class is None:
 225             if utils._is_uint64(default_cs):
 226                 raise ValueError('stream activity messages in this stream cannot have a known default clock snapshot')
 227
 228     def _create_stream_beginning_message(self, stream):
 229         utils._check_type(stream, bt2.stream._Stream)
 230
 231         ptr = native_bt.message_stream_beginning_create(self._ptr, stream._ptr)
 232         if ptr is None:
 233             raise bt2.CreationError('cannot create stream beginning message object')
 234
 235         return bt2.message._StreamBeginningMessage(ptr)
 236
 237     def _create_stream_activity_beginning_message(self, stream,
 238                                                   default_clock_snapshot=_unknown_clock_snapshot):
 239         utils._check_type(stream, bt2.stream._Stream)
 240         self._validate_stream_activity_message_default_clock_snapshot(stream, default_clock_snapshot)
 241         ptr = native_bt.message_stream_activity_beginning_create(self._ptr, stream._ptr)
 242
 243         if ptr is None:
 244             raise bt2.CreationError(
 245                 'cannot create stream activity beginning message object')
 246
 247         msg = bt2.message._StreamActivityBeginningMessage(ptr)
 248         msg._default_clock_snapshot = default_clock_snapshot
 249         return msg
 250
 251     def _create_stream_activity_end_message(self, stream,
 252                                             default_clock_snapshot=_unknown_clock_snapshot):
 253         utils._check_type(stream, bt2.stream._Stream)
 254         self._validate_stream_activity_message_default_clock_snapshot(stream, default_clock_snapshot)
 255         ptr = native_bt.message_stream_activity_end_create(self._ptr, stream._ptr)
 256
 257         if ptr is None:
 258             raise bt2.CreationError(
 259                 'cannot create stream activity end message object')
 260
 261         msg = bt2.message._StreamActivityEndMessage(ptr)
 262         msg._default_clock_snapshot = default_clock_snapshot
 263         return msg
 264
 265     def _create_stream_end_message(self, stream):
 266         utils._check_type(stream, bt2.stream._Stream)
 267
 268         ptr = native_bt.message_stream_end_create(self._ptr, stream._ptr)
 269         if ptr is None:
 270             raise bt2.CreationError('cannot create stream end message object')
 271
 272         return bt2.message._StreamEndMessage(ptr)
 273
 274     def _create_packet_beginning_message(self, packet, default_clock_snapshot=None):
 275         utils._check_type(packet, bt2.packet._Packet)
 276
 277         if packet.stream.cls.packets_have_beginning_default_clock_snapshot:
 278             if default_clock_snapshot is None:
 279                 raise ValueError("packet beginning messages in this stream must have a default clock snapshot")
 280
 281             utils._check_uint64(default_clock_snapshot)
 282             ptr = native_bt.message_packet_beginning_create_with_default_clock_snapshot(
 283                 self._ptr, packet._ptr, default_clock_snapshot)
 284         else:
 285             if default_clock_snapshot is not None:
 286                 raise ValueError("packet beginning messages in this stream must not have a default clock snapshot")
 287
 288             ptr = native_bt.message_packet_beginning_create(self._ptr, packet._ptr)
 289
 290         if ptr is None:
 291             raise bt2.CreationError('cannot create packet beginning message object')
 292
 293         return bt2.message._PacketBeginningMessage(ptr)
 294
 295     def _create_packet_end_message(self, packet, default_clock_snapshot=None):
 296         utils._check_type(packet, bt2.packet._Packet)
 297
 298         if packet.stream.cls.packets_have_end_default_clock_snapshot:
 299             if default_clock_snapshot is None:
 300                 raise ValueError("packet end messages in this stream must have a default clock snapshot")
 301
 302             utils._check_uint64(default_clock_snapshot)
 303             ptr = native_bt.message_packet_end_create_with_default_clock_snapshot(
 304                 self._ptr, packet._ptr, default_clock_snapshot)
 305         else:
 306             if default_clock_snapshot is not None:
 307                 raise ValueError("packet end messages in this stream must not have a default clock snapshot")
 308
 309             ptr = native_bt.message_packet_end_create(self._ptr, packet._ptr)
 310
 311         if ptr is None:
 312             raise bt2.CreationError('cannot create packet end message object')
 313
 314         return bt2.message._PacketEndMessage(ptr)
 315
 316     def _create_discarded_events_message(self, stream, count=None,
 317                                          beg_clock_snapshot=None,
 318                                          end_clock_snapshot=None):
 319         utils._check_type(stream, bt2.stream._Stream)
 320
 321         if not stream.cls.supports_discarded_events:
 322             raise ValueError('stream class does not support discarded events')
 323
 324         if stream.cls.discarded_events_have_default_clock_snapshots:
 325             if beg_clock_snapshot is None or end_clock_snapshot is None:
 326                 raise ValueError('discarded events have default clock snapshots for this stream class')
 327
 328             utils._check_uint64(beg_clock_snapshot)
 329             utils._check_uint64(end_clock_snapshot)
 330             ptr = native_bt.message_discarded_events_create_with_default_clock_snapshots(
 331                 self._ptr, stream._ptr, beg_clock_snapshot, end_clock_snapshot)
 332         else:
 333             if beg_clock_snapshot is not None or end_clock_snapshot is not None:
 334                 raise ValueError('discarded events have no default clock snapshots for this stream class')
 335
 336             ptr = native_bt.message_discarded_events_create(
 337                 self._ptr, stream._ptr)
 338
 339         if ptr is None:
 340             raise bt2.CreationError('cannot discarded events message object')
 341
 342         msg = bt2.message._DiscardedEventsMessage(ptr)
 343
 344         if count is not None:
 345             msg._count = count
 346
 347         return msg
 348
 349     def _create_discarded_packets_message(self, stream, count=None, beg_clock_snapshot=None, end_clock_snapshot=None):
 350         utils._check_type(stream, bt2.stream._Stream)
 351
 352         if not stream.cls.supports_discarded_packets:
 353             raise ValueError('stream class does not support discarded packets')
 354
 355         if stream.cls.discarded_packets_have_default_clock_snapshots:
 356             if beg_clock_snapshot is None or end_clock_snapshot is None:
 357                 raise ValueError('discarded packets have default clock snapshots for this stream class')
 358
 359             utils._check_uint64(beg_clock_snapshot)
 360             utils._check_uint64(end_clock_snapshot)
 361             ptr = native_bt.message_discarded_packets_create_with_default_clock_snapshots(
 362                 self._ptr, stream._ptr, beg_clock_snapshot, end_clock_snapshot)
 363         else:
 364             if beg_clock_snapshot is not None or end_clock_snapshot is not None:
 365                 raise ValueError('discarded packets have no default clock snapshots for this stream class')
 366
 367             ptr = native_bt.message_discarded_packets_create(
 368                 self._ptr, stream._ptr)
 369
 370         if ptr is None:
 371             raise bt2.CreationError('cannot discarded packets message object')
 372
 373         msg = bt2.message._DiscardedPacketsMessage(ptr)
 374
 375         if count is not None:
 376             msg._count = count
 377
 378         return msg
 379