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         status, res = self._can_seek_beginning(self._ptr)
  62         utils._handle_func_status(
  63             status,
  64             'cannot check whether or not message iterator can seek its beginning',
  65         )
  66         return res != 0
  67
  68     def seek_beginning(self):
  69         # Forget about buffered messages, they won't be valid after seeking.
  70         self._current_msgs.clear()
  71         self._at = 0
  72
  73         status = self._seek_beginning(self._ptr)
  74         utils._handle_func_status(status, 'cannot seek message iterator beginning')
  75
  76
  77 # This is created when a component wants to iterate on one of its input ports.
  78 class _UserComponentInputPortMessageIterator(_GenericMessageIterator):
  79     _get_msg_range = staticmethod(native_bt.bt2_self_component_port_input_get_msg_range)
  80     _get_ref = staticmethod(
  81         native_bt.self_component_port_input_message_iterator_get_ref
  82     )
  83     _put_ref = staticmethod(
  84         native_bt.self_component_port_input_message_iterator_put_ref
  85     )
  86     _can_seek_beginning = staticmethod(
  87         native_bt.self_component_port_input_message_iterator_can_seek_beginning
  88     )
  89     _seek_beginning = staticmethod(
  90         native_bt.self_component_port_input_message_iterator_seek_beginning
  91     )
  92
  93
  94 # This is extended by the user to implement component classes in Python.  It
  95 # is created for a given output port when an input port message iterator is
  96 # created on the input port on the other side of the connection.  It is also
  97 # created when an output port message iterator is created on this output port.
  98 #
  99 # Its purpose is to feed the messages that should go out through this output
 100 # port.
 101 class _UserMessageIterator(_MessageIterator):
 102     def __new__(cls, ptr):
 103         # User iterator objects are always created by the native side,
 104         # that is, never instantiated directly by Python code.
 105         #
 106         # The native code calls this, then manually calls
 107         # self.__init__() without the `ptr` argument. The user has
 108         # access to self.component during this call, thanks to this
 109         # self._bt_ptr argument being set.
 110         #
 111         # self._bt_ptr is NOT owned by this object here, so there's nothing
 112         # to do in __del__().
 113         self = super().__new__(cls)
 114         self._bt_ptr = ptr
 115         return self
 116
 117     def _bt_init_from_native(self, self_output_port_ptr):
 118         self_output_port = bt2_port._create_self_from_ptr_and_get_ref(
 119             self_output_port_ptr, native_bt.PORT_TYPE_OUTPUT
 120         )
 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.bt2_get_user_component_from_user_msg_iter(self._bt_ptr)
 129
 130     @property
 131     def _port(self):
 132         port_ptr = native_bt.self_message_iterator_borrow_port(self._bt_ptr)
 133         assert port_ptr is not None
 134         return bt2_port._create_self_from_ptr_and_get_ref(
 135             port_ptr, native_bt.PORT_TYPE_OUTPUT
 136         )
 137
 138     @property
 139     def addr(self):
 140         return int(self._bt_ptr)
 141
 142     @property
 143     def _is_interrupted(self):
 144         return bool(native_bt.self_message_iterator_is_interrupted(self._bt_ptr))
 145
 146     def _user_finalize(self):
 147         pass
 148
 149     def __next__(self):
 150         raise bt2.Stop
 151
 152     def _bt_next_from_native(self):
 153         # this can raise anything: it's catched by the native part
 154         try:
 155             msg = next(self)
 156         except StopIteration:
 157             raise bt2.Stop
 158         except Exception:
 159             raise
 160
 161         utils._check_type(msg, bt2_message._MessageConst)
 162
 163         # The reference we return will be given to the message array.
 164         # However, the `msg` Python object may stay alive, if the user has kept
 165         # a reference to it.  Acquire a new reference to account for that.
 166         msg._get_ref(msg._ptr)
 167         return int(msg._ptr)
 168
 169     @property
 170     def _bt_can_seek_beginning_from_native(self):
 171         # Here, we mimic the behavior of the C API:
 172         #
 173         # - If the iterator has a _user_can_seek_beginning attribute,
 174         #   read it and use that result.
 175         # - Otherwise, the presence or absence of a `_user_seek_beginning`
 176         #   method indicates whether the iterator can seek beginning.
 177         if hasattr(self, '_user_can_seek_beginning'):
 178             can_seek_beginning = self._user_can_seek_beginning
 179             utils._check_bool(can_seek_beginning)
 180             return can_seek_beginning
 181         else:
 182             return hasattr(self, '_user_seek_beginning')
 183
 184     def _bt_seek_beginning_from_native(self):
 185         self._user_seek_beginning()
 186
 187     def _create_input_port_message_iterator(self, input_port):
 188         utils._check_type(input_port, bt2_port._UserComponentInputPort)
 189
 190         status, msg_iter_ptr = native_bt.bt2_self_component_port_input_message_iterator_create_from_message_iterator(
 191             self._bt_ptr, input_port._ptr
 192         )
 193         utils._handle_func_status(status, 'cannot create message iterator object')
 194         assert msg_iter_ptr is not None
 195
 196         return _UserComponentInputPortMessageIterator(msg_iter_ptr)
 197
 198     def _create_event_message(self, event_class, parent, default_clock_snapshot=None):
 199         utils._check_type(event_class, bt2_event_class._EventClass)
 200
 201         if event_class.stream_class.supports_packets:
 202             utils._check_type(parent, bt2_packet._Packet)
 203         else:
 204             utils._check_type(parent, bt2_stream._Stream)
 205
 206         if default_clock_snapshot is not None:
 207             if event_class.stream_class.default_clock_class is None:
 208                 raise ValueError(
 209                     'event messages in this stream must not have a default clock snapshot'
 210                 )
 211
 212             utils._check_uint64(default_clock_snapshot)
 213
 214             if event_class.stream_class.supports_packets:
 215                 ptr = native_bt.message_event_create_with_packet_and_default_clock_snapshot(
 216                     self._bt_ptr, event_class._ptr, parent._ptr, default_clock_snapshot
 217                 )
 218             else:
 219                 ptr = native_bt.message_event_create_with_default_clock_snapshot(
 220                     self._bt_ptr, event_class._ptr, parent._ptr, default_clock_snapshot
 221                 )
 222         else:
 223             if event_class.stream_class.default_clock_class is not None:
 224                 raise ValueError(
 225                     'event messages in this stream must have a default clock snapshot'
 226                 )
 227
 228             if event_class.stream_class.supports_packets:
 229                 ptr = native_bt.message_event_create_with_packet(
 230                     self._bt_ptr, event_class._ptr, parent._ptr
 231                 )
 232             else:
 233                 ptr = native_bt.message_event_create(
 234                     self._bt_ptr, event_class._ptr, parent._ptr
 235                 )
 236
 237         if ptr is None:
 238             raise bt2._MemoryError('cannot create event message object')
 239
 240         return bt2_message._EventMessage(ptr)
 241
 242     def _create_message_iterator_inactivity_message(self, clock_class, clock_snapshot):
 243         utils._check_type(clock_class, bt2_clock_class._ClockClass)
 244         ptr = native_bt.message_message_iterator_inactivity_create(
 245             self._bt_ptr, clock_class._ptr, clock_snapshot
 246         )
 247
 248         if ptr is None:
 249             raise bt2._MemoryError('cannot create inactivity message object')
 250
 251         return bt2_message._MessageIteratorInactivityMessage(ptr)
 252
 253     def _create_stream_beginning_message(self, stream, default_clock_snapshot=None):
 254         utils._check_type(stream, bt2_stream._Stream)
 255
 256         ptr = native_bt.message_stream_beginning_create(self._bt_ptr, stream._ptr)
 257         if ptr is None:
 258             raise bt2._MemoryError('cannot create stream beginning message object')
 259
 260         msg = bt2_message._StreamBeginningMessage(ptr)
 261
 262         if default_clock_snapshot is not None:
 263             msg._default_clock_snapshot = default_clock_snapshot
 264
 265         return msg
 266
 267     def _create_stream_end_message(self, stream, default_clock_snapshot=None):
 268         utils._check_type(stream, bt2_stream._Stream)
 269
 270         ptr = native_bt.message_stream_end_create(self._bt_ptr, stream._ptr)
 271         if ptr is None:
 272             raise bt2._MemoryError('cannot create stream end message object')
 273
 274         msg = bt2_message._StreamEndMessage(ptr)
 275
 276         if default_clock_snapshot is not None:
 277             msg._default_clock_snapshot = default_clock_snapshot
 278
 279         return msg
 280
 281     def _create_packet_beginning_message(self, packet, default_clock_snapshot=None):
 282         utils._check_type(packet, bt2_packet._Packet)
 283
 284         if packet.stream.cls.packets_have_beginning_default_clock_snapshot:
 285             if default_clock_snapshot is None:
 286                 raise ValueError(
 287                     "packet beginning messages in this stream must have a default clock snapshot"
 288                 )
 289
 290             utils._check_uint64(default_clock_snapshot)
 291             ptr = native_bt.message_packet_beginning_create_with_default_clock_snapshot(
 292                 self._bt_ptr, packet._ptr, default_clock_snapshot
 293             )
 294         else:
 295             if default_clock_snapshot is not None:
 296                 raise ValueError(
 297                     "packet beginning messages in this stream must not have a default clock snapshot"
 298                 )
 299
 300             ptr = native_bt.message_packet_beginning_create(self._bt_ptr, packet._ptr)
 301
 302         if ptr is None:
 303             raise bt2._MemoryError('cannot create packet beginning message object')
 304
 305         return bt2_message._PacketBeginningMessage(ptr)
 306
 307     def _create_packet_end_message(self, packet, default_clock_snapshot=None):
 308         utils._check_type(packet, bt2_packet._Packet)
 309
 310         if packet.stream.cls.packets_have_end_default_clock_snapshot:
 311             if default_clock_snapshot is None:
 312                 raise ValueError(
 313                     "packet end messages in this stream must have a default clock snapshot"
 314                 )
 315
 316             utils._check_uint64(default_clock_snapshot)
 317             ptr = native_bt.message_packet_end_create_with_default_clock_snapshot(
 318                 self._bt_ptr, packet._ptr, default_clock_snapshot
 319             )
 320         else:
 321             if default_clock_snapshot is not None:
 322                 raise ValueError(
 323                     "packet end messages in this stream must not have a default clock snapshot"
 324                 )
 325
 326             ptr = native_bt.message_packet_end_create(self._bt_ptr, packet._ptr)
 327
 328         if ptr is None:
 329             raise bt2._MemoryError('cannot create packet end message object')
 330
 331         return bt2_message._PacketEndMessage(ptr)
 332
 333     def _create_discarded_events_message(
 334         self, stream, count=None, beg_clock_snapshot=None, end_clock_snapshot=None
 335     ):
 336         utils._check_type(stream, bt2_stream._Stream)
 337
 338         if not stream.cls.supports_discarded_events:
 339             raise ValueError('stream class does not support discarded events')
 340
 341         if stream.cls.discarded_events_have_default_clock_snapshots:
 342             if beg_clock_snapshot is None or end_clock_snapshot is None:
 343                 raise ValueError(
 344                     'discarded events have default clock snapshots for this stream class'
 345                 )
 346
 347             utils._check_uint64(beg_clock_snapshot)
 348             utils._check_uint64(end_clock_snapshot)
 349             ptr = native_bt.message_discarded_events_create_with_default_clock_snapshots(
 350                 self._bt_ptr, stream._ptr, beg_clock_snapshot, end_clock_snapshot
 351             )
 352         else:
 353             if beg_clock_snapshot is not None or end_clock_snapshot is not None:
 354                 raise ValueError(
 355                     'discarded events have no default clock snapshots for this stream class'
 356                 )
 357
 358             ptr = native_bt.message_discarded_events_create(self._bt_ptr, stream._ptr)
 359
 360         if ptr is None:
 361             raise bt2._MemoryError('cannot discarded events message object')
 362
 363         msg = bt2_message._DiscardedEventsMessage(ptr)
 364
 365         if count is not None:
 366             msg._count = count
 367
 368         return msg
 369
 370     def _create_discarded_packets_message(
 371         self, stream, count=None, beg_clock_snapshot=None, end_clock_snapshot=None
 372     ):
 373         utils._check_type(stream, bt2_stream._Stream)
 374
 375         if not stream.cls.supports_discarded_packets:
 376             raise ValueError('stream class does not support discarded packets')
 377
 378         if stream.cls.discarded_packets_have_default_clock_snapshots:
 379             if beg_clock_snapshot is None or end_clock_snapshot is None:
 380                 raise ValueError(
 381                     'discarded packets have default clock snapshots for this stream class'
 382                 )
 383
 384             utils._check_uint64(beg_clock_snapshot)
 385             utils._check_uint64(end_clock_snapshot)
 386             ptr = native_bt.message_discarded_packets_create_with_default_clock_snapshots(
 387                 self._bt_ptr, stream._ptr, beg_clock_snapshot, end_clock_snapshot
 388             )
 389         else:
 390             if beg_clock_snapshot is not None or end_clock_snapshot is not None:
 391                 raise ValueError(
 392                     'discarded packets have no default clock snapshots for this stream class'
 393                 )
 394
 395             ptr = native_bt.message_discarded_packets_create(self._bt_ptr, stream._ptr)
 396
 397         if ptr is None:
 398             raise bt2._MemoryError('cannot discarded packets message object')
 399
 400         msg = bt2_message._DiscardedPacketsMessage(ptr)
 401
 402         if count is not None:
 403             msg._count = count
 404
 405         return msg