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 stream as bt2_stream
  27 from bt2 import event_class as bt2_event_class
  28 from bt2 import packet as bt2_packet
  29 from bt2 import port as bt2_port
  30 from bt2 import clock_class as bt2_clock_class
  31 import bt2
  32
  33
  34 class _MessageIterator(collections.abc.Iterator):
  35     def __next__(self):
  36         raise NotImplementedError
  37
  38
  39 class _UserComponentInputPortMessageIterator(object._SharedObject, _MessageIterator):
  40     _get_ref = staticmethod(
  41         native_bt.self_component_port_input_message_iterator_get_ref
  42     )
  43     _put_ref = staticmethod(
  44         native_bt.self_component_port_input_message_iterator_put_ref
  45     )
  46
  47     def __init__(self, ptr):
  48         self._current_msgs = []
  49         self._at = 0
  50         super().__init__(ptr)
  51
  52     def __next__(self):
  53         if len(self._current_msgs) == self._at:
  54             status, msgs = native_bt.bt2_self_component_port_input_get_msg_range(
  55                 self._ptr
  56             )
  57             utils._handle_func_status(
  58                 status, 'unexpected error: cannot advance the message iterator'
  59             )
  60             self._current_msgs = msgs
  61             self._at = 0
  62
  63         msg_ptr = self._current_msgs[self._at]
  64         self._at += 1
  65
  66         return bt2_message._create_from_ptr(msg_ptr)
  67
  68     def can_seek_beginning(self):
  69         status, res = native_bt.self_component_port_input_message_iterator_can_seek_beginning(
  70             self._ptr
  71         )
  72         utils._handle_func_status(
  73             status,
  74             'cannot check whether or not message iterator can seek its beginning',
  75         )
  76         return res != 0
  77
  78     def seek_beginning(self):
  79         # Forget about buffered messages, they won't be valid after seeking.
  80         self._current_msgs.clear()
  81         self._at = 0
  82
  83         status = native_bt.self_component_port_input_message_iterator_seek_beginning(
  84             self._ptr
  85         )
  86         utils._handle_func_status(status, 'cannot seek message iterator beginning')
  87
  88
  89 # This is extended by the user to implement component classes in Python.  It
  90 # is created for a given output port when an input port message iterator is
  91 # created on the input port on the other side of the connection.  It is also
  92 # created when an output port message iterator is created on this output port.
  93 #
  94 # Its purpose is to feed the messages that should go out through this output
  95 # port.
  96 class _UserMessageIterator(_MessageIterator):
  97     def __new__(cls, ptr):
  98         # User iterator objects are always created by the native side,
  99         # that is, never instantiated directly by Python code.
 100         #
 101         # The native code calls this, then manually calls
 102         # self.__init__() without the `ptr` argument. The user has
 103         # access to self.component during this call, thanks to this
 104         # self._bt_ptr argument being set.
 105         #
 106         # self._bt_ptr is NOT owned by this object here, so there's nothing
 107         # to do in __del__().
 108         self = super().__new__(cls)
 109         self._bt_ptr = ptr
 110         return self
 111
 112     def _bt_init_from_native(self, self_output_port_ptr):
 113         self_output_port = bt2_port._create_self_from_ptr_and_get_ref(
 114             self_output_port_ptr, native_bt.PORT_TYPE_OUTPUT
 115         )
 116         self.__init__(self_output_port)
 117
 118     def __init__(self, output_port):
 119         pass
 120
 121     @property
 122     def _component(self):
 123         return native_bt.bt2_get_user_component_from_user_msg_iter(self._bt_ptr)
 124
 125     @property
 126     def _port(self):
 127         port_ptr = native_bt.self_message_iterator_borrow_port(self._bt_ptr)
 128         assert port_ptr is not None
 129         return bt2_port._create_self_from_ptr_and_get_ref(
 130             port_ptr, native_bt.PORT_TYPE_OUTPUT
 131         )
 132
 133     @property
 134     def addr(self):
 135         return int(self._bt_ptr)
 136
 137     @property
 138     def _is_interrupted(self):
 139         return bool(native_bt.self_message_iterator_is_interrupted(self._bt_ptr))
 140
 141     def _user_finalize(self):
 142         pass
 143
 144     def __next__(self):
 145         raise bt2.Stop
 146
 147     def _bt_next_from_native(self):
 148         # this can raise anything: it's catched by the native part
 149         try:
 150             msg = next(self)
 151         except StopIteration:
 152             raise bt2.Stop
 153         except Exception:
 154             raise
 155
 156         utils._check_type(msg, bt2_message._MessageConst)
 157
 158         # The reference we return will be given to the message array.
 159         # However, the `msg` Python object may stay alive, if the user has kept
 160         # a reference to it.  Acquire a new reference to account for that.
 161         msg._get_ref(msg._ptr)
 162         return int(msg._ptr)
 163
 164     def _bt_can_seek_beginning_from_native(self):
 165         # Here, we mimic the behavior of the C API:
 166         #
 167         # - If the iterator has a _user_can_seek_beginning method,
 168         #   read it and use that result.
 169         # - Otherwise, the presence or absence of a `_user_seek_beginning`
 170         #   method indicates whether the iterator can seek beginning.
 171         if hasattr(self, '_user_can_seek_beginning'):
 172             can_seek_beginning = self._user_can_seek_beginning()
 173             utils._check_bool(can_seek_beginning)
 174             return can_seek_beginning
 175         else:
 176             return hasattr(self, '_user_seek_beginning')
 177
 178     def _bt_seek_beginning_from_native(self):
 179         self._user_seek_beginning()
 180
 181     def _create_input_port_message_iterator(self, input_port):
 182         utils._check_type(input_port, bt2_port._UserComponentInputPort)
 183
 184         status, msg_iter_ptr = native_bt.bt2_self_component_port_input_message_iterator_create_from_message_iterator(
 185             self._bt_ptr, input_port._ptr
 186         )
 187         utils._handle_func_status(status, 'cannot create message iterator object')
 188         assert msg_iter_ptr is not None
 189
 190         return _UserComponentInputPortMessageIterator(msg_iter_ptr)
 191
 192     def _create_event_message(self, event_class, parent, default_clock_snapshot=None):
 193         utils._check_type(event_class, bt2_event_class._EventClass)
 194
 195         if event_class.stream_class.supports_packets:
 196             utils._check_type(parent, bt2_packet._Packet)
 197         else:
 198             utils._check_type(parent, bt2_stream._Stream)
 199
 200         if default_clock_snapshot is not None:
 201             if event_class.stream_class.default_clock_class is None:
 202                 raise ValueError(
 203                     'event messages in this stream must not have a default clock snapshot'
 204                 )
 205
 206             utils._check_uint64(default_clock_snapshot)
 207
 208             if event_class.stream_class.supports_packets:
 209                 ptr = native_bt.message_event_create_with_packet_and_default_clock_snapshot(
 210                     self._bt_ptr, event_class._ptr, parent._ptr, default_clock_snapshot
 211                 )
 212             else:
 213                 ptr = native_bt.message_event_create_with_default_clock_snapshot(
 214                     self._bt_ptr, event_class._ptr, parent._ptr, default_clock_snapshot
 215                 )
 216         else:
 217             if event_class.stream_class.default_clock_class is not None:
 218                 raise ValueError(
 219                     'event messages in this stream must have a default clock snapshot'
 220                 )
 221
 222             if event_class.stream_class.supports_packets:
 223                 ptr = native_bt.message_event_create_with_packet(
 224                     self._bt_ptr, event_class._ptr, parent._ptr
 225                 )
 226             else:
 227                 ptr = native_bt.message_event_create(
 228                     self._bt_ptr, event_class._ptr, parent._ptr
 229                 )
 230
 231         if ptr is None:
 232             raise bt2._MemoryError('cannot create event message object')
 233
 234         return bt2_message._EventMessage(ptr)
 235
 236     def _create_message_iterator_inactivity_message(self, clock_class, clock_snapshot):
 237         utils._check_type(clock_class, bt2_clock_class._ClockClass)
 238         ptr = native_bt.message_message_iterator_inactivity_create(
 239             self._bt_ptr, clock_class._ptr, clock_snapshot
 240         )
 241
 242         if ptr is None:
 243             raise bt2._MemoryError('cannot create inactivity message object')
 244
 245         return bt2_message._MessageIteratorInactivityMessage(ptr)
 246
 247     def _create_stream_beginning_message(self, stream, default_clock_snapshot=None):
 248         utils._check_type(stream, bt2_stream._Stream)
 249
 250         ptr = native_bt.message_stream_beginning_create(self._bt_ptr, stream._ptr)
 251         if ptr is None:
 252             raise bt2._MemoryError('cannot create stream beginning message object')
 253
 254         msg = bt2_message._StreamBeginningMessage(ptr)
 255
 256         if default_clock_snapshot is not None:
 257             msg._default_clock_snapshot = default_clock_snapshot
 258
 259         return msg
 260
 261     def _create_stream_end_message(self, stream, default_clock_snapshot=None):
 262         utils._check_type(stream, bt2_stream._Stream)
 263
 264         ptr = native_bt.message_stream_end_create(self._bt_ptr, stream._ptr)
 265         if ptr is None:
 266             raise bt2._MemoryError('cannot create stream end message object')
 267
 268         msg = bt2_message._StreamEndMessage(ptr)
 269
 270         if default_clock_snapshot is not None:
 271             msg._default_clock_snapshot = default_clock_snapshot
 272
 273         return msg
 274
 275     def _create_packet_beginning_message(self, packet, default_clock_snapshot=None):
 276         utils._check_type(packet, bt2_packet._Packet)
 277
 278         if packet.stream.cls.packets_have_beginning_default_clock_snapshot:
 279             if default_clock_snapshot is None:
 280                 raise ValueError(
 281                     "packet beginning messages in this stream must have a default clock snapshot"
 282                 )
 283
 284             utils._check_uint64(default_clock_snapshot)
 285             ptr = native_bt.message_packet_beginning_create_with_default_clock_snapshot(
 286                 self._bt_ptr, packet._ptr, default_clock_snapshot
 287             )
 288         else:
 289             if default_clock_snapshot is not None:
 290                 raise ValueError(
 291                     "packet beginning messages in this stream must not have a default clock snapshot"
 292                 )
 293
 294             ptr = native_bt.message_packet_beginning_create(self._bt_ptr, packet._ptr)
 295
 296         if ptr is None:
 297             raise bt2._MemoryError('cannot create packet beginning message object')
 298
 299         return bt2_message._PacketBeginningMessage(ptr)
 300
 301     def _create_packet_end_message(self, packet, default_clock_snapshot=None):
 302         utils._check_type(packet, bt2_packet._Packet)
 303
 304         if packet.stream.cls.packets_have_end_default_clock_snapshot:
 305             if default_clock_snapshot is None:
 306                 raise ValueError(
 307                     "packet end messages in this stream must have a default clock snapshot"
 308                 )
 309
 310             utils._check_uint64(default_clock_snapshot)
 311             ptr = native_bt.message_packet_end_create_with_default_clock_snapshot(
 312                 self._bt_ptr, packet._ptr, default_clock_snapshot
 313             )
 314         else:
 315             if default_clock_snapshot is not None:
 316                 raise ValueError(
 317                     "packet end messages in this stream must not have a default clock snapshot"
 318                 )
 319
 320             ptr = native_bt.message_packet_end_create(self._bt_ptr, packet._ptr)
 321
 322         if ptr is None:
 323             raise bt2._MemoryError('cannot create packet end message object')
 324
 325         return bt2_message._PacketEndMessage(ptr)
 326
 327     def _create_discarded_events_message(
 328         self, stream, count=None, beg_clock_snapshot=None, end_clock_snapshot=None
 329     ):
 330         utils._check_type(stream, bt2_stream._Stream)
 331
 332         if not stream.cls.supports_discarded_events:
 333             raise ValueError('stream class does not support discarded events')
 334
 335         if stream.cls.discarded_events_have_default_clock_snapshots:
 336             if beg_clock_snapshot is None or end_clock_snapshot is None:
 337                 raise ValueError(
 338                     'discarded events have default clock snapshots for this stream class'
 339                 )
 340
 341             utils._check_uint64(beg_clock_snapshot)
 342             utils._check_uint64(end_clock_snapshot)
 343             ptr = native_bt.message_discarded_events_create_with_default_clock_snapshots(
 344                 self._bt_ptr, stream._ptr, beg_clock_snapshot, end_clock_snapshot
 345             )
 346         else:
 347             if beg_clock_snapshot is not None or end_clock_snapshot is not None:
 348                 raise ValueError(
 349                     'discarded events have no default clock snapshots for this stream class'
 350                 )
 351
 352             ptr = native_bt.message_discarded_events_create(self._bt_ptr, stream._ptr)
 353
 354         if ptr is None:
 355             raise bt2._MemoryError('cannot discarded events message object')
 356
 357         msg = bt2_message._DiscardedEventsMessage(ptr)
 358
 359         if count is not None:
 360             msg._count = count
 361
 362         return msg
 363
 364     def _create_discarded_packets_message(
 365         self, stream, count=None, beg_clock_snapshot=None, end_clock_snapshot=None
 366     ):
 367         utils._check_type(stream, bt2_stream._Stream)
 368
 369         if not stream.cls.supports_discarded_packets:
 370             raise ValueError('stream class does not support discarded packets')
 371
 372         if stream.cls.discarded_packets_have_default_clock_snapshots:
 373             if beg_clock_snapshot is None or end_clock_snapshot is None:
 374                 raise ValueError(
 375                     'discarded packets have default clock snapshots for this stream class'
 376                 )
 377
 378             utils._check_uint64(beg_clock_snapshot)
 379             utils._check_uint64(end_clock_snapshot)
 380             ptr = native_bt.message_discarded_packets_create_with_default_clock_snapshots(
 381                 self._bt_ptr, stream._ptr, beg_clock_snapshot, end_clock_snapshot
 382             )
 383         else:
 384             if beg_clock_snapshot is not None or end_clock_snapshot is not None:
 385                 raise ValueError(
 386                     'discarded packets have no default clock snapshots for this stream class'
 387                 )
 388
 389             ptr = native_bt.message_discarded_packets_create(self._bt_ptr, stream._ptr)
 390
 391         if ptr is None:
 392             raise bt2._MemoryError('cannot discarded packets message object')
 393
 394         msg = bt2_message._DiscardedPacketsMessage(ptr)
 395
 396         if count is not None:
 397             msg._count = count
 398
 399         return msg