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