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