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 _GenericMessageIterator(object._SharedObject, _MessageIterator):
  40     def __init__(self, ptr):
  41         self._current_msgs = []
  42         self._at = 0
  43         super().__init__(ptr)
  44
  45     def __next__(self):
  46         if len(self._current_msgs) == self._at:
  47             status, msgs = self._get_msg_range(self._ptr)
  48             utils._handle_func_status(
  49                 status, 'unexpected error: cannot advance the message iterator'
  50             )
  51             self._current_msgs = msgs
  52             self._at = 0
  53
  54         msg_ptr = self._current_msgs[self._at]
  55         self._at += 1
  56
  57         return bt2_message._create_from_ptr(msg_ptr)
  58
  59     @property
  60     def can_seek_beginning(self):
  61         res = self._can_seek_beginning(self._ptr)
  62         return res != 0
  63
  64     def seek_beginning(self):
  65         # Forget about buffered messages, they won't be valid after seeking.
  66         self._current_msgs.clear()
  67         self._at = 0
  68
  69         status = self._seek_beginning(self._ptr)
  70         utils._handle_func_status(status, 'cannot seek message iterator beginning')
  71
  72
  73 # This is created when a component wants to iterate on one of its input ports.
  74 class _UserComponentInputPortMessageIterator(_GenericMessageIterator):
  75     _get_msg_range = staticmethod(native_bt.bt2_self_component_port_input_get_msg_range)
  76     _get_ref = staticmethod(
  77         native_bt.self_component_port_input_message_iterator_get_ref
  78     )
  79     _put_ref = staticmethod(
  80         native_bt.self_component_port_input_message_iterator_put_ref
  81     )
  82     _can_seek_beginning = staticmethod(
  83         native_bt.self_component_port_input_message_iterator_can_seek_beginning
  84     )
  85     _seek_beginning = staticmethod(
  86         native_bt.self_component_port_input_message_iterator_seek_beginning
  87     )
  88
  89
  90 # This is extended by the user to implement component classes in Python.  It
  91 # is created for a given output port when an input port message iterator is
  92 # created on the input port on the other side of the connection.  It is also
  93 # created when an output port message iterator is created on this output port.
  94 #
  95 # Its purpose is to feed the messages that should go out through this output
  96 # port.
  97 class _UserMessageIterator(_MessageIterator):
  98     def __new__(cls, ptr):
  99         # User iterator objects are always created by the native side,
 100         # that is, never instantiated directly by Python code.
 101         #
 102         # The native code calls this, then manually calls
 103         # self.__init__() without the `ptr` argument. The user has
 104         # access to self.component during this call, thanks to this
 105         # self._bt_ptr argument being set.
 106         #
 107         # self._bt_ptr is NOT owned by this object here, so there's nothing
 108         # to do in __del__().
 109         self = super().__new__(cls)
 110         self._bt_ptr = ptr
 111         return self
 112
 113     def _bt_init_from_native(self, self_output_port_ptr):
 114         self_output_port = bt2_port._create_self_from_ptr_and_get_ref(
 115             self_output_port_ptr, native_bt.PORT_TYPE_OUTPUT
 116         )
 117         self.__init__(self_output_port)
 118
 119     def __init__(self, output_port):
 120         pass
 121
 122     @property
 123     def _component(self):
 124         return native_bt.bt2_get_user_component_from_user_msg_iter(self._bt_ptr)
 125
 126     @property
 127     def _port(self):
 128         port_ptr = native_bt.self_message_iterator_borrow_port(self._bt_ptr)
 129         assert port_ptr is not None
 130         return bt2_port._create_self_from_ptr_and_get_ref(
 131             port_ptr, native_bt.PORT_TYPE_OUTPUT
 132         )
 133
 134     @property
 135     def addr(self):
 136         return int(self._bt_ptr)
 137
 138     @property
 139     def _is_interrupted(self):
 140         return bool(native_bt.self_message_iterator_is_interrupted(self._bt_ptr))
 141
 142     def _user_finalize(self):
 143         pass
 144
 145     def __next__(self):
 146         raise bt2.Stop
 147
 148     def _bt_next_from_native(self):
 149         # this can raise anything: it's catched by the native part
 150         try:
 151             msg = next(self)
 152         except StopIteration:
 153             raise bt2.Stop
 154         except Exception:
 155             raise
 156
 157         utils._check_type(msg, bt2_message._MessageConst)
 158
 159         # The reference we return will be given to the message array.
 160         # However, the `msg` Python object may stay alive, if the user has kept
 161         # a reference to it.  Acquire a new reference to account for that.
 162         msg._get_ref(msg._ptr)
 163         return int(msg._ptr)
 164
 165     @property
 166     def _bt_can_seek_beginning_from_native(self):
 167         # Here, we mimic the behavior of the C API:
 168         #
 169         # - If the iterator has a _user_can_seek_beginning attribute,
 170         #   read it and use that result.
 171         # - Otherwise, the presence or absence of a `_user_seek_beginning`
 172         #   method indicates whether the iterator can seek beginning.
 173         if hasattr(self, '_user_can_seek_beginning'):
 174             can_seek_beginning = self._user_can_seek_beginning
 175             utils._check_bool(can_seek_beginning)
 176             return can_seek_beginning
 177         else:
 178             return hasattr(self, '_user_seek_beginning')
 179
 180     def _bt_seek_beginning_from_native(self):
 181         self._user_seek_beginning()
 182
 183     def _create_input_port_message_iterator(self, input_port):
 184         utils._check_type(input_port, bt2_port._UserComponentInputPort)
 185
 186         status, msg_iter_ptr = native_bt.bt2_self_component_port_input_message_iterator_create_from_message_iterator(
 187             self._bt_ptr, input_port._ptr
 188         )
 189         utils._handle_func_status(status, 'cannot create message iterator object')
 190         assert msg_iter_ptr is not None
 191
 192         return _UserComponentInputPortMessageIterator(msg_iter_ptr)
 193
 194     def _create_event_message(self, event_class, parent, default_clock_snapshot=None):
 195         utils._check_type(event_class, bt2_event_class._EventClass)
 196
 197         if event_class.stream_class.supports_packets:
 198             utils._check_type(parent, bt2_packet._Packet)
 199         else:
 200             utils._check_type(parent, bt2_stream._Stream)
 201
 202         if default_clock_snapshot is not None:
 203             if event_class.stream_class.default_clock_class is None:
 204                 raise ValueError(
 205                     'event messages in this stream must not have a default clock snapshot'
 206                 )
 207
 208             utils._check_uint64(default_clock_snapshot)
 209
 210             if event_class.stream_class.supports_packets:
 211                 ptr = native_bt.message_event_create_with_packet_and_default_clock_snapshot(
 212                     self._bt_ptr, event_class._ptr, parent._ptr, default_clock_snapshot
 213                 )
 214             else:
 215                 ptr = native_bt.message_event_create_with_default_clock_snapshot(
 216                     self._bt_ptr, event_class._ptr, parent._ptr, default_clock_snapshot
 217                 )
 218         else:
 219             if event_class.stream_class.default_clock_class is not None:
 220                 raise ValueError(
 221                     'event messages in this stream must have a default clock snapshot'
 222                 )
 223
 224             if event_class.stream_class.supports_packets:
 225                 ptr = native_bt.message_event_create_with_packet(
 226                     self._bt_ptr, event_class._ptr, parent._ptr
 227                 )
 228             else:
 229                 ptr = native_bt.message_event_create(
 230                     self._bt_ptr, event_class._ptr, parent._ptr
 231                 )
 232
 233         if ptr is None:
 234             raise bt2._MemoryError('cannot create event message object')
 235
 236         return bt2_message._EventMessage(ptr)
 237
 238     def _create_message_iterator_inactivity_message(self, clock_class, clock_snapshot):
 239         utils._check_type(clock_class, bt2_clock_class._ClockClass)
 240         ptr = native_bt.message_message_iterator_inactivity_create(
 241             self._bt_ptr, clock_class._ptr, clock_snapshot
 242         )
 243
 244         if ptr is None:
 245             raise bt2._MemoryError('cannot create inactivity message object')
 246
 247         return bt2_message._MessageIteratorInactivityMessage(ptr)
 248
 249     def _create_stream_beginning_message(self, stream, default_clock_snapshot=None):
 250         utils._check_type(stream, bt2_stream._Stream)
 251
 252         ptr = native_bt.message_stream_beginning_create(self._bt_ptr, stream._ptr)
 253         if ptr is None:
 254             raise bt2._MemoryError('cannot create stream beginning message object')
 255
 256         msg = bt2_message._StreamBeginningMessage(ptr)
 257
 258         if default_clock_snapshot is not None:
 259             msg._default_clock_snapshot = default_clock_snapshot
 260
 261         return msg
 262
 263     def _create_stream_end_message(self, stream, default_clock_snapshot=None):
 264         utils._check_type(stream, bt2_stream._Stream)
 265
 266         ptr = native_bt.message_stream_end_create(self._bt_ptr, stream._ptr)
 267         if ptr is None:
 268             raise bt2._MemoryError('cannot create stream end message object')
 269
 270         msg = bt2_message._StreamEndMessage(ptr)
 271
 272         if default_clock_snapshot is not None:
 273             msg._default_clock_snapshot = default_clock_snapshot
 274
 275         return msg
 276
 277     def _create_packet_beginning_message(self, packet, default_clock_snapshot=None):
 278         utils._check_type(packet, bt2_packet._Packet)
 279
 280         if packet.stream.cls.packets_have_beginning_default_clock_snapshot:
 281             if default_clock_snapshot is None:
 282                 raise ValueError(
 283                     "packet beginning messages in this stream must have a default clock snapshot"
 284                 )
 285
 286             utils._check_uint64(default_clock_snapshot)
 287             ptr = native_bt.message_packet_beginning_create_with_default_clock_snapshot(
 288                 self._bt_ptr, packet._ptr, default_clock_snapshot
 289             )
 290         else:
 291             if default_clock_snapshot is not None:
 292                 raise ValueError(
 293                     "packet beginning messages in this stream must not have a default clock snapshot"
 294                 )
 295
 296             ptr = native_bt.message_packet_beginning_create(self._bt_ptr, packet._ptr)
 297
 298         if ptr is None:
 299             raise bt2._MemoryError('cannot create packet beginning message object')
 300
 301         return bt2_message._PacketBeginningMessage(ptr)
 302
 303     def _create_packet_end_message(self, packet, default_clock_snapshot=None):
 304         utils._check_type(packet, bt2_packet._Packet)
 305
 306         if packet.stream.cls.packets_have_end_default_clock_snapshot:
 307             if default_clock_snapshot is None:
 308                 raise ValueError(
 309                     "packet end messages in this stream must have a default clock snapshot"
 310                 )
 311
 312             utils._check_uint64(default_clock_snapshot)
 313             ptr = native_bt.message_packet_end_create_with_default_clock_snapshot(
 314                 self._bt_ptr, packet._ptr, default_clock_snapshot
 315             )
 316         else:
 317             if default_clock_snapshot is not None:
 318                 raise ValueError(
 319                     "packet end messages in this stream must not have a default clock snapshot"
 320                 )
 321
 322             ptr = native_bt.message_packet_end_create(self._bt_ptr, packet._ptr)
 323
 324         if ptr is None:
 325             raise bt2._MemoryError('cannot create packet end message object')
 326
 327         return bt2_message._PacketEndMessage(ptr)
 328
 329     def _create_discarded_events_message(
 330         self, stream, count=None, beg_clock_snapshot=None, end_clock_snapshot=None
 331     ):
 332         utils._check_type(stream, bt2_stream._Stream)
 333
 334         if not stream.cls.supports_discarded_events:
 335             raise ValueError('stream class does not support discarded events')
 336
 337         if stream.cls.discarded_events_have_default_clock_snapshots:
 338             if beg_clock_snapshot is None or end_clock_snapshot is None:
 339                 raise ValueError(
 340                     'discarded events have default clock snapshots for this stream class'
 341                 )
 342
 343             utils._check_uint64(beg_clock_snapshot)
 344             utils._check_uint64(end_clock_snapshot)
 345             ptr = native_bt.message_discarded_events_create_with_default_clock_snapshots(
 346                 self._bt_ptr, stream._ptr, beg_clock_snapshot, end_clock_snapshot
 347             )
 348         else:
 349             if beg_clock_snapshot is not None or end_clock_snapshot is not None:
 350                 raise ValueError(
 351                     'discarded events have no default clock snapshots for this stream class'
 352                 )
 353
 354             ptr = native_bt.message_discarded_events_create(self._bt_ptr, stream._ptr)
 355
 356         if ptr is None:
 357             raise bt2._MemoryError('cannot discarded events message object')
 358
 359         msg = bt2_message._DiscardedEventsMessage(ptr)
 360
 361         if count is not None:
 362             msg._count = count
 363
 364         return msg
 365
 366     def _create_discarded_packets_message(
 367         self, stream, count=None, beg_clock_snapshot=None, end_clock_snapshot=None
 368     ):
 369         utils._check_type(stream, bt2_stream._Stream)
 370
 371         if not stream.cls.supports_discarded_packets:
 372             raise ValueError('stream class does not support discarded packets')
 373
 374         if stream.cls.discarded_packets_have_default_clock_snapshots:
 375             if beg_clock_snapshot is None or end_clock_snapshot is None:
 376                 raise ValueError(
 377                     'discarded packets have default clock snapshots for this stream class'
 378                 )
 379
 380             utils._check_uint64(beg_clock_snapshot)
 381             utils._check_uint64(end_clock_snapshot)
 382             ptr = native_bt.message_discarded_packets_create_with_default_clock_snapshots(
 383                 self._bt_ptr, stream._ptr, beg_clock_snapshot, end_clock_snapshot
 384             )
 385         else:
 386             if beg_clock_snapshot is not None or end_clock_snapshot is not None:
 387                 raise ValueError(
 388                     'discarded packets have no default clock snapshots for this stream class'
 389                 )
 390
 391             ptr = native_bt.message_discarded_packets_create(self._bt_ptr, stream._ptr)
 392
 393         if ptr is None:
 394             raise bt2._MemoryError('cannot discarded packets message object')
 395
 396         msg = bt2_message._DiscardedPacketsMessage(ptr)
 397
 398         if count is not None:
 399             msg._count = count
 400
 401         return msg