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     def _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:
 154             raise
 155
 156         utils._check_type(msg, bt2.message._Message)
 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     @property
 165     def _bt_can_seek_beginning_from_native(self):
 166         # Here, we mimic the behavior of the C API:
 167         #
 168         # - If the iterator has a _can_seek_beginning attribute, read it and use
 169         #   that result.
 170         # - Otherwise, the presence or absence of a `_seek_beginning`
 171         #   method indicates whether the iterator can seek beginning.
 172         if hasattr(self, '_can_seek_beginning'):
 173             can_seek_beginning = self._can_seek_beginning
 174             utils._check_bool(can_seek_beginning)
 175             return can_seek_beginning
 176         else:
 177             return hasattr(self, '_seek_beginning')
 178
 179     def _bt_seek_beginning_from_native(self):
 180         self._seek_beginning()
 181
 182     def _create_input_port_message_iterator(self, input_port):
 183         utils._check_type(input_port, bt2.port._UserComponentInputPort)
 184
 185         msg_iter_ptr = native_bt.self_component_port_input_message_iterator_create_from_message_iterator(
 186             self._bt_ptr, input_port._ptr
 187         )
 188
 189         if msg_iter_ptr is None:
 190             raise bt2.CreationError('cannot create message iterator object')
 191
 192         return _UserComponentInputPortMessageIterator(msg_iter_ptr)
 193
 194     def _create_event_message(
 195         self, event_class, parent=None, default_clock_snapshot=None
 196     ):
 197         utils._check_type(event_class, bt2.event_class._EventClass)
 198
 199         if event_class.stream_class.supports_packets:
 200             utils._check_type(parent, bt2.packet._Packet)
 201         else:
 202             utils._check_type(parent, bt2.stream._Stream)
 203
 204         if default_clock_snapshot is not None:
 205             if event_class.stream_class.default_clock_class is None:
 206                 raise ValueError(
 207                     'event messages in this stream must not have a default clock snapshot'
 208                 )
 209
 210             utils._check_uint64(default_clock_snapshot)
 211
 212             if event_class.stream_class.supports_packets:
 213                 ptr = native_bt.message_event_create_with_packet_and_default_clock_snapshot(
 214                     self._bt_ptr, event_class._ptr, parent._ptr, default_clock_snapshot
 215                 )
 216             else:
 217                 ptr = native_bt.message_event_create_with_default_clock_snapshot(
 218                     self._bt_ptr, event_class._ptr, parent._ptr, default_clock_snapshot
 219                 )
 220         else:
 221             if event_class.stream_class.default_clock_class is not None:
 222                 raise ValueError(
 223                     'event messages in this stream must have a default clock snapshot'
 224                 )
 225
 226             if event_class.stream_class.supports_packets:
 227                 ptr = native_bt.message_event_create_with_packet(
 228                     self._bt_ptr, event_class._ptr, parent._ptr
 229                 )
 230             else:
 231                 ptr = native_bt.message_event_create(
 232                     self._bt_ptr, event_class._ptr, parent._ptr
 233                 )
 234
 235         if ptr is None:
 236             raise bt2._MemoryError('cannot create event message object')
 237
 238         return bt2.message._EventMessage(ptr)
 239
 240     def _create_message_iterator_inactivity_message(self, clock_class, clock_snapshot):
 241         utils._check_type(clock_class, bt2.clock_class._ClockClass)
 242         ptr = native_bt.message_message_iterator_inactivity_create(
 243             self._bt_ptr, clock_class._ptr, clock_snapshot
 244         )
 245
 246         if ptr is None:
 247             raise bt2._MemoryError('cannot create inactivity message object')
 248
 249         return bt2.message._MessageIteratorInactivityMessage(ptr)
 250
 251     def _create_stream_beginning_message(self, stream, default_clock_snapshot=None):
 252         utils._check_type(stream, bt2.stream._Stream)
 253
 254         ptr = native_bt.message_stream_beginning_create(self._bt_ptr, stream._ptr)
 255         if ptr is None:
 256             raise bt2._MemoryError('cannot create stream beginning message object')
 257
 258         msg = bt2.message._StreamBeginningMessage(ptr)
 259
 260         if default_clock_snapshot is not None:
 261             msg._default_clock_snapshot = default_clock_snapshot
 262
 263         return msg
 264
 265     def _create_stream_end_message(self, stream, default_clock_snapshot=None):
 266         utils._check_type(stream, bt2.stream._Stream)
 267
 268         ptr = native_bt.message_stream_end_create(self._bt_ptr, stream._ptr)
 269         if ptr is None:
 270             raise bt2._MemoryError('cannot create stream end message object')
 271
 272         msg = bt2.message._StreamEndMessage(ptr)
 273
 274         if default_clock_snapshot is not None:
 275             msg._default_clock_snapshot = default_clock_snapshot
 276
 277         return msg
 278
 279     def _create_packet_beginning_message(self, packet, default_clock_snapshot=None):
 280         utils._check_type(packet, bt2.packet._Packet)
 281
 282         if packet.stream.cls.packets_have_beginning_default_clock_snapshot:
 283             if default_clock_snapshot is None:
 284                 raise ValueError(
 285                     "packet beginning messages in this stream must have a default clock snapshot"
 286                 )
 287
 288             utils._check_uint64(default_clock_snapshot)
 289             ptr = native_bt.message_packet_beginning_create_with_default_clock_snapshot(
 290                 self._bt_ptr, packet._ptr, default_clock_snapshot
 291             )
 292         else:
 293             if default_clock_snapshot is not None:
 294                 raise ValueError(
 295                     "packet beginning messages in this stream must not have a default clock snapshot"
 296                 )
 297
 298             ptr = native_bt.message_packet_beginning_create(self._bt_ptr, packet._ptr)
 299
 300         if ptr is None:
 301             raise bt2._MemoryError('cannot create packet beginning message object')
 302
 303         return bt2.message._PacketBeginningMessage(ptr)
 304
 305     def _create_packet_end_message(self, packet, default_clock_snapshot=None):
 306         utils._check_type(packet, bt2.packet._Packet)
 307
 308         if packet.stream.cls.packets_have_end_default_clock_snapshot:
 309             if default_clock_snapshot is None:
 310                 raise ValueError(
 311                     "packet end messages in this stream must have a default clock snapshot"
 312                 )
 313
 314             utils._check_uint64(default_clock_snapshot)
 315             ptr = native_bt.message_packet_end_create_with_default_clock_snapshot(
 316                 self._bt_ptr, packet._ptr, default_clock_snapshot
 317             )
 318         else:
 319             if default_clock_snapshot is not None:
 320                 raise ValueError(
 321                     "packet end messages in this stream must not have a default clock snapshot"
 322                 )
 323
 324             ptr = native_bt.message_packet_end_create(self._bt_ptr, packet._ptr)
 325
 326         if ptr is None:
 327             raise bt2._MemoryError('cannot create packet end message object')
 328
 329         return bt2.message._PacketEndMessage(ptr)
 330
 331     def _create_discarded_events_message(
 332         self, stream, count=None, beg_clock_snapshot=None, end_clock_snapshot=None
 333     ):
 334         utils._check_type(stream, bt2.stream._Stream)
 335
 336         if not stream.cls.supports_discarded_events:
 337             raise ValueError('stream class does not support discarded events')
 338
 339         if stream.cls.discarded_events_have_default_clock_snapshots:
 340             if beg_clock_snapshot is None or end_clock_snapshot is None:
 341                 raise ValueError(
 342                     'discarded events have default clock snapshots for this stream class'
 343                 )
 344
 345             utils._check_uint64(beg_clock_snapshot)
 346             utils._check_uint64(end_clock_snapshot)
 347             ptr = native_bt.message_discarded_events_create_with_default_clock_snapshots(
 348                 self._bt_ptr, stream._ptr, beg_clock_snapshot, end_clock_snapshot
 349             )
 350         else:
 351             if beg_clock_snapshot is not None or end_clock_snapshot is not None:
 352                 raise ValueError(
 353                     'discarded events have no default clock snapshots for this stream class'
 354                 )
 355
 356             ptr = native_bt.message_discarded_events_create(self._bt_ptr, stream._ptr)
 357
 358         if ptr is None:
 359             raise bt2._MemoryError('cannot discarded events message object')
 360
 361         msg = bt2.message._DiscardedEventsMessage(ptr)
 362
 363         if count is not None:
 364             msg._count = count
 365
 366         return msg
 367
 368     def _create_discarded_packets_message(
 369         self, stream, count=None, beg_clock_snapshot=None, end_clock_snapshot=None
 370     ):
 371         utils._check_type(stream, bt2.stream._Stream)
 372
 373         if not stream.cls.supports_discarded_packets:
 374             raise ValueError('stream class does not support discarded packets')
 375
 376         if stream.cls.discarded_packets_have_default_clock_snapshots:
 377             if beg_clock_snapshot is None or end_clock_snapshot is None:
 378                 raise ValueError(
 379                     'discarded packets have default clock snapshots for this stream class'
 380                 )
 381
 382             utils._check_uint64(beg_clock_snapshot)
 383             utils._check_uint64(end_clock_snapshot)
 384             ptr = native_bt.message_discarded_packets_create_with_default_clock_snapshots(
 385                 self._bt_ptr, stream._ptr, beg_clock_snapshot, end_clock_snapshot
 386             )
 387         else:
 388             if beg_clock_snapshot is not None or end_clock_snapshot is not None:
 389                 raise ValueError(
 390                     'discarded packets have no default clock snapshots for this stream class'
 391                 )
 392
 393             ptr = native_bt.message_discarded_packets_create(self._bt_ptr, stream._ptr)
 394
 395         if ptr is None:
 396             raise bt2._MemoryError('cannot discarded packets message object')
 397
 398         msg = bt2.message._DiscardedPacketsMessage(ptr)
 399
 400         if count is not None:
 401             msg._count = count
 402
 403         return msg