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(status,
  45                                       'unexpected error: cannot advance the message iterator')
  46             self._current_msgs = msgs
  47             self._at = 0
  48
  49         msg_ptr = self._current_msgs[self._at]
  50         self._at += 1
  51
  52         return bt2.message._create_from_ptr(msg_ptr)
  53
  54     @property
  55     def can_seek_beginning(self):
  56         res = self._can_seek_beginning(self._ptr)
  57         return res != 0
  58
  59     def seek_beginning(self):
  60         # Forget about buffered messages, they won't be valid after seeking..
  61         self._current_msgs.clear()
  62         self._at = 0
  63
  64         status = self._seek_beginning(self._ptr)
  65         utils._handle_func_status(status,
  66                                   '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(native_bt.self_component_port_input_message_iterator_get_ref)
  73     _put_ref = staticmethod(native_bt.self_component_port_input_message_iterator_put_ref)
  74     _can_seek_beginning = staticmethod(native_bt.self_component_port_input_message_iterator_can_seek_beginning)
  75     _seek_beginning = staticmethod(native_bt.self_component_port_input_message_iterator_seek_beginning)
  76
  77
  78 # This is created when the user wants to iterate on a component's output port,
  79 # from outside the graph.
  80 class _OutputPortMessageIterator(_GenericMessageIterator):
  81     _get_msg_range = staticmethod(native_bt.bt2_port_output_get_msg_range)
  82     _get_ref = staticmethod(native_bt.port_output_message_iterator_get_ref)
  83     _put_ref = staticmethod(native_bt.port_output_message_iterator_put_ref)
  84     _can_seek_beginning = staticmethod(native_bt.port_output_message_iterator_can_seek_beginning)
  85     _seek_beginning = staticmethod(native_bt.port_output_message_iterator_seek_beginning)
  86
  87
  88 # This is extended by the user to implement component classes in Python.  It
  89 # is created for a given output port when an input port message iterator is
  90 # created on the input port on the other side of the connection.  It is also
  91 # created when an output port message iterator is created on this output port.
  92 #
  93 # Its purpose is to feed the messages that should go out through this output
  94 # port.
  95 class _UserMessageIterator(_MessageIterator):
  96     def __new__(cls, ptr):
  97         # User iterator objects are always created by the native side,
  98         # that is, never instantiated directly by Python code.
  99         #
 100         # The native code calls this, then manually calls
 101         # self.__init__() without the `ptr` argument. The user has
 102         # access to self.component during this call, thanks to this
 103         # self._bt_ptr argument being set.
 104         #
 105         # self._bt_ptr is NOT owned by this object here, so there's nothing
 106         # to do in __del__().
 107         self = super().__new__(cls)
 108         self._bt_ptr = ptr
 109         return self
 110
 111     def _bt_init_from_native(self, self_output_port_ptr):
 112         self_output_port = bt2.port._create_self_from_ptr_and_get_ref(
 113             self_output_port_ptr, native_bt.PORT_TYPE_OUTPUT)
 114         self.__init__(self_output_port)
 115
 116     def __init__(self, output_port):
 117         pass
 118
 119     @property
 120     def _component(self):
 121         return native_bt.bt2_get_user_component_from_user_msg_iter(self._bt_ptr)
 122
 123     @property
 124     def addr(self):
 125         return int(self._bt_ptr)
 126
 127     def _finalize(self):
 128         pass
 129
 130     def __next__(self):
 131         raise bt2.Stop
 132
 133     def _bt_next_from_native(self):
 134         # this can raise anything: it's catched by the native part
 135         try:
 136             msg = next(self)
 137         except StopIteration:
 138             raise bt2.Stop
 139         except:
 140             raise
 141
 142         utils._check_type(msg, bt2.message._Message)
 143
 144         # The reference we return will be given to the message array.
 145         # However, the `msg` Python object may stay alive, if the user has kept
 146         # a reference to it.  Acquire a new reference to account for that.
 147         msg._get_ref(msg._ptr)
 148         return int(msg._ptr)
 149
 150     @property
 151     def _bt_can_seek_beginning_from_native(self):
 152         # Here, we mimic the behavior of the C API:
 153         #
 154         # - If the iterator has a _can_seek_beginning attribute, read it and use
 155         #   that result.
 156         # - Otherwise, the presence or absence of a `_seek_beginning`
 157         #   method indicates whether the iterator can seek beginning.
 158         if hasattr(self, '_can_seek_beginning'):
 159             can_seek_beginning = self._can_seek_beginning
 160             utils._check_bool(can_seek_beginning)
 161             return can_seek_beginning
 162         else:
 163             return hasattr(self, '_seek_beginning')
 164
 165     def _bt_seek_beginning_from_native(self):
 166         self._seek_beginning()
 167
 168     def _create_event_message(self, event_class, packet, default_clock_snapshot=None):
 169         utils._check_type(event_class, bt2.event_class._EventClass)
 170         utils._check_type(packet, bt2.packet._Packet)
 171
 172         if default_clock_snapshot is not None:
 173             if event_class.stream_class.default_clock_class is None:
 174                 raise ValueError('event messages in this stream must not have a default clock snapshot')
 175
 176             utils._check_uint64(default_clock_snapshot)
 177             ptr = native_bt.message_event_create_with_default_clock_snapshot(
 178                 self._bt_ptr, event_class._ptr, packet._ptr, default_clock_snapshot)
 179         else:
 180             if event_class.stream_class.default_clock_class is not None:
 181                 raise ValueError('event messages in this stream must have a default clock snapshot')
 182
 183             ptr = native_bt.message_event_create(
 184                 self._bt_ptr, event_class._ptr, packet._ptr)
 185
 186         if ptr is None:
 187             raise bt2.CreationError('cannot create event message object')
 188
 189         return bt2.message._EventMessage(ptr)
 190
 191     def _create_message_iterator_inactivity_message(self, clock_class, clock_snapshot):
 192         utils._check_type(clock_class, bt2.clock_class._ClockClass)
 193         ptr = native_bt.message_message_iterator_inactivity_create(
 194             self._bt_ptr, clock_class._ptr, clock_snapshot)
 195
 196         if ptr is None:
 197             raise bt2.CreationError('cannot create inactivity message object')
 198
 199         return bt2.message._MessageIteratorInactivityMessage(ptr)
 200
 201     def _create_stream_beginning_message(self, stream, default_clock_snapshot=None):
 202         utils._check_type(stream, bt2.stream._Stream)
 203
 204         ptr = native_bt.message_stream_beginning_create(self._bt_ptr, stream._ptr)
 205         if ptr is None:
 206             raise bt2.CreationError('cannot create stream beginning message object')
 207
 208         msg = bt2.message._StreamBeginningMessage(ptr)
 209
 210         if default_clock_snapshot is not None:
 211             msg._default_clock_snapshot = default_clock_snapshot
 212
 213         return msg
 214
 215     def _create_stream_end_message(self, stream, default_clock_snapshot=None):
 216         utils._check_type(stream, bt2.stream._Stream)
 217
 218         ptr = native_bt.message_stream_end_create(self._bt_ptr, stream._ptr)
 219         if ptr is None:
 220             raise bt2.CreationError('cannot create stream end message object')
 221
 222         msg = bt2.message._StreamEndMessage(ptr)
 223
 224         if default_clock_snapshot is not None:
 225             msg._default_clock_snapshot = default_clock_snapshot
 226
 227         return msg
 228
 229     def _create_packet_beginning_message(self, packet, default_clock_snapshot=None):
 230         utils._check_type(packet, bt2.packet._Packet)
 231
 232         if packet.stream.cls.packets_have_beginning_default_clock_snapshot:
 233             if default_clock_snapshot is None:
 234                 raise ValueError("packet beginning messages in this stream must have a default clock snapshot")
 235
 236             utils._check_uint64(default_clock_snapshot)
 237             ptr = native_bt.message_packet_beginning_create_with_default_clock_snapshot(
 238                 self._bt_ptr, packet._ptr, default_clock_snapshot)
 239         else:
 240             if default_clock_snapshot is not None:
 241                 raise ValueError("packet beginning messages in this stream must not have a default clock snapshot")
 242
 243             ptr = native_bt.message_packet_beginning_create(self._bt_ptr, packet._ptr)
 244
 245         if ptr is None:
 246             raise bt2.CreationError('cannot create packet beginning message object')
 247
 248         return bt2.message._PacketBeginningMessage(ptr)
 249
 250     def _create_packet_end_message(self, packet, default_clock_snapshot=None):
 251         utils._check_type(packet, bt2.packet._Packet)
 252
 253         if packet.stream.cls.packets_have_end_default_clock_snapshot:
 254             if default_clock_snapshot is None:
 255                 raise ValueError("packet end messages in this stream must have a default clock snapshot")
 256
 257             utils._check_uint64(default_clock_snapshot)
 258             ptr = native_bt.message_packet_end_create_with_default_clock_snapshot(
 259                 self._bt_ptr, packet._ptr, default_clock_snapshot)
 260         else:
 261             if default_clock_snapshot is not None:
 262                 raise ValueError("packet end messages in this stream must not have a default clock snapshot")
 263
 264             ptr = native_bt.message_packet_end_create(self._bt_ptr, packet._ptr)
 265
 266         if ptr is None:
 267             raise bt2.CreationError('cannot create packet end message object')
 268
 269         return bt2.message._PacketEndMessage(ptr)
 270
 271     def _create_discarded_events_message(self, stream, count=None,
 272                                          beg_clock_snapshot=None,
 273                                          end_clock_snapshot=None):
 274         utils._check_type(stream, bt2.stream._Stream)
 275
 276         if not stream.cls.supports_discarded_events:
 277             raise ValueError('stream class does not support discarded events')
 278
 279         if stream.cls.discarded_events_have_default_clock_snapshots:
 280             if beg_clock_snapshot is None or end_clock_snapshot is None:
 281                 raise ValueError('discarded events have default clock snapshots for this stream class')
 282
 283             utils._check_uint64(beg_clock_snapshot)
 284             utils._check_uint64(end_clock_snapshot)
 285             ptr = native_bt.message_discarded_events_create_with_default_clock_snapshots(
 286                 self._bt_ptr, stream._ptr, beg_clock_snapshot, end_clock_snapshot)
 287         else:
 288             if beg_clock_snapshot is not None or end_clock_snapshot is not None:
 289                 raise ValueError('discarded events have no default clock snapshots for this stream class')
 290
 291             ptr = native_bt.message_discarded_events_create(
 292                 self._bt_ptr, stream._ptr)
 293
 294         if ptr is None:
 295             raise bt2.CreationError('cannot discarded events message object')
 296
 297         msg = bt2.message._DiscardedEventsMessage(ptr)
 298
 299         if count is not None:
 300             msg._count = count
 301
 302         return msg
 303
 304     def _create_discarded_packets_message(self, stream, count=None, beg_clock_snapshot=None, end_clock_snapshot=None):
 305         utils._check_type(stream, bt2.stream._Stream)
 306
 307         if not stream.cls.supports_discarded_packets:
 308             raise ValueError('stream class does not support discarded packets')
 309
 310         if stream.cls.discarded_packets_have_default_clock_snapshots:
 311             if beg_clock_snapshot is None or end_clock_snapshot is None:
 312                 raise ValueError('discarded packets have default clock snapshots for this stream class')
 313
 314             utils._check_uint64(beg_clock_snapshot)
 315             utils._check_uint64(end_clock_snapshot)
 316             ptr = native_bt.message_discarded_packets_create_with_default_clock_snapshots(
 317                 self._bt_ptr, stream._ptr, beg_clock_snapshot, end_clock_snapshot)
 318         else:
 319             if beg_clock_snapshot is not None or end_clock_snapshot is not None:
 320                 raise ValueError('discarded packets have no default clock snapshots for this stream class')
 321
 322             ptr = native_bt.message_discarded_packets_create(
 323                 self._bt_ptr, stream._ptr)
 324
 325         if ptr is None:
 326             raise bt2.CreationError('cannot discarded packets message object')
 327
 328         msg = bt2.message._DiscardedPacketsMessage(ptr)
 329
 330         if count is not None:
 331             msg._count = count
 332
 333         return msg
 334