bindings/python/bt2/bt2/component.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_iterator
  25 import collections.abc
  26 import bt2.value
  27 import traceback
  28 import bt2.port
  29 import sys
  30 import bt2
  31 import os
  32
  33
  34 _env_var = os.environ.get('BABELTRACE_PYTHON_BT2_NO_TRACEBACK')
  35 _NO_PRINT_TRACEBACK = _env_var == '1'
  36
  37
  38 # This class wraps a component class pointer. This component class could
  39 # have been created by Python code, but since we only have the pointer,
  40 # we can only wrap it in a generic way and lose the original Python
  41 # class.
  42 #
  43 # Subclasses must implement some methods that this base class uses:
  44 #
  45 #   - _as_component_class_ptr: static method, convert the passed component class
  46 #     pointer to a 'bt_component_class *'.
  47
  48 class _GenericComponentClass(object._SharedObject):
  49     @property
  50     def name(self):
  51         ptr = self._as_component_class_ptr(self._ptr)
  52         name = native_bt.component_class_get_name(ptr)
  53         assert name is not None
  54         return name
  55
  56     @property
  57     def description(self):
  58         ptr = self._as_component_class_ptr(self._ptr)
  59         return native_bt.component_class_get_description(ptr)
  60
  61     @property
  62     def help(self):
  63         ptr = self._as_component_class_ptr(self._ptr)
  64         return native_bt.component_class_get_help(ptr)
  65
  66     def _component_class_ptr(self):
  67         return self._as_component_class_ptr(self._ptr)
  68
  69     def __eq__(self, other):
  70         if not isinstance(other, _GenericComponentClass):
  71             try:
  72                 if not issubclass(other, _UserComponent):
  73                     return False
  74             except TypeError:
  75                 return False
  76
  77         return self.addr == other.addr
  78
  79
  80 class _GenericSourceComponentClass(_GenericComponentClass):
  81     _get_ref = native_bt.component_class_source_get_ref
  82     _put_ref = native_bt.component_class_source_put_ref
  83     _as_component_class_ptr = native_bt.component_class_source_as_component_class
  84
  85
  86 class _GenericFilterComponentClass(_GenericComponentClass):
  87     _get_ref = native_bt.component_class_filter_get_ref
  88     _put_ref = native_bt.component_class_filter_put_ref
  89     _as_component_class_ptr = native_bt.component_class_filter_as_component_class
  90
  91
  92 class _GenericSinkComponentClass(_GenericComponentClass):
  93     _get_ref = native_bt.component_class_sink_get_ref
  94     _put_ref = native_bt.component_class_sink_put_ref
  95     _as_component_class_ptr = native_bt.component_class_sink_as_component_class
  96
  97
  98 def _handle_component_status(status, gen_error_msg):
  99     if status == native_bt.COMPONENT_STATUS_END:
 100         raise bt2.Stop
 101     elif status == native_bt.COMPONENT_STATUS_AGAIN:
 102         raise bt2.TryAgain
 103     elif status == native_bt.COMPONENT_STATUS_UNSUPPORTED:
 104         raise bt2.UnsupportedFeature
 105     elif status == native_bt.COMPONENT_STATUS_REFUSE_PORT_CONNECTION:
 106         raise bt2.PortConnectionRefused
 107     elif status == native_bt.COMPONENT_STATUS_GRAPH_IS_CANCELED:
 108         raise bt2.GraphCanceled
 109     elif status < 0:
 110         raise bt2.Error(gen_error_msg)
 111
 112
 113 class _PortIterator(collections.abc.Iterator):
 114     def __init__(self, comp_ports):
 115         self._comp_ports = comp_ports
 116         self._at = 0
 117
 118     def __next__(self):
 119         if self._at == len(self._comp_ports):
 120             raise StopIteration
 121
 122         comp_ports = self._comp_ports
 123         comp_ptr = comp_ports._component._ptr
 124         port_ptr = comp_ports._get_port_at_index_fn(comp_ptr, self._at)
 125         assert(port_ptr)
 126
 127         if comp_ports._is_private:
 128             port_pub_ptr = native_bt.port_from_private(port_ptr)
 129             name = native_bt.port_get_name(port_pub_ptr)
 130             native_bt.put(port_pub_ptr)
 131         else:
 132             name = native_bt.port_get_name(port_ptr)
 133
 134         assert(name is not None)
 135         native_bt.put(port_ptr)
 136         self._at += 1
 137         return name
 138
 139
 140 class _ComponentPorts(collections.abc.Mapping):
 141     def __init__(self, is_private, component,
 142                  get_port_by_name_fn, get_port_at_index_fn,
 143                  get_port_count_fn):
 144         self._is_private = is_private
 145         self._component = component
 146         self._get_port_by_name_fn = get_port_by_name_fn
 147         self._get_port_at_index_fn = get_port_at_index_fn
 148         self._get_port_count_fn = get_port_count_fn
 149
 150     def __getitem__(self, key):
 151         utils._check_str(key)
 152         port_ptr = self._get_port_by_name_fn(self._component._ptr, key)
 153
 154         if port_ptr is None:
 155             raise KeyError(key)
 156
 157         if self._is_private:
 158             return bt2.port._create_private_from_ptr(port_ptr)
 159         else:
 160             return bt2.port._create_from_ptr(port_ptr)
 161
 162     def __len__(self):
 163         if self._is_private:
 164             pub_ptr = native_bt.component_from_private(self._component._ptr)
 165             count = self._get_port_count_fn(pub_ptr)
 166             native_bt.put(pub_ptr)
 167         else:
 168             count = self._get_port_count_fn(self._component._ptr)
 169
 170         assert(count >= 0)
 171         return count
 172
 173     def __iter__(self):
 174         return _PortIterator(self)
 175
 176
 177 # This class holds the methods which are common to both generic
 178 # component objects and Python user component objects.
 179 #
 180 # Subclasses must provide these methods or property:
 181 #
 182 #   - _borrow_component_class_ptr: static method, must return a pointer to the
 183 #     specialized component class (e.g. 'bt_component_class_sink *') of the
 184 #     passed specialized component pointer (e.g. 'bt_component_sink *').
 185 #   - _comp_cls_type: property, one of the native_bt.COMPONENT_CLASS_TYPE_*
 186 #     constants.
 187 #   - _as_component_ptr: static method, must return the passed specialized
 188 #     component pointer (e.g. 'bt_component_sink *') as a 'bt_component *'.
 189
 190 class _Component:
 191     @property
 192     def name(self):
 193         ptr = self._as_component_ptr(self._ptr)
 194         name = native_bt.component_get_name(ptr)
 195         assert name is not None
 196         return name
 197
 198     @property
 199     def component_class(self):
 200         cc_ptr = self._borrow_component_class_ptr(self._ptr)
 201         assert cc_ptr is not None
 202         return _create_component_class_from_ptr_and_get_ref(cc_ptr, self._comp_cls_type)
 203
 204     def __eq__(self, other):
 205         if not hasattr(other, 'addr'):
 206             return False
 207
 208         return self.addr == other.addr
 209
 210
 211 class _SourceComponent(_Component):
 212     _borrow_component_class_ptr = native_bt.component_source_borrow_class_const
 213     _comp_cls_type = native_bt.COMPONENT_CLASS_TYPE_SOURCE
 214     _as_component_class_ptr = native_bt.component_class_source_as_component_class
 215     _as_component_ptr = native_bt.component_source_as_component_const
 216
 217
 218 class _FilterComponent(_Component):
 219     _borrow_component_class_ptr = native_bt.component_filter_borrow_class_const
 220     _comp_cls_type = native_bt.COMPONENT_CLASS_TYPE_FILTER
 221     _as_component_class_ptr = native_bt.component_class_filter_as_component_class
 222     _as_component_ptr = native_bt.component_filter_as_component_const
 223
 224
 225 class _SinkComponent(_Component):
 226     _borrow_component_class_ptr = native_bt.component_sink_borrow_class_const
 227     _comp_cls_type = native_bt.COMPONENT_CLASS_TYPE_SINK
 228     _as_component_class_ptr = native_bt.component_class_sink_as_component_class
 229     _as_component_ptr = native_bt.component_sink_as_component_const
 230
 231
 232 # This is analogous to _GenericSourceComponentClass, but for source
 233 # component objects.
 234 class _GenericSourceComponent(object._SharedObject, _SourceComponent):
 235     @property
 236     def output_ports(self):
 237         return _ComponentPorts(False, self,
 238                                native_bt.component_source_get_output_port_by_name,
 239                                native_bt.component_source_get_output_port_by_index,
 240                                native_bt.component_source_get_output_port_count)
 241
 242
 243 # This is analogous to _GenericFilterComponentClass, but for filter
 244 # component objects.
 245 class _GenericFilterComponent(object._SharedObject, _FilterComponent):
 246     @property
 247     def output_ports(self):
 248         return _ComponentPorts(False, self,
 249                                native_bt.component_filter_get_output_port_by_name,
 250                                native_bt.component_filter_get_output_port_by_index,
 251                                native_bt.component_filter_get_output_port_count)
 252
 253     @property
 254     def input_ports(self):
 255         return _ComponentPorts(False, self,
 256                                native_bt.component_filter_get_input_port_by_name,
 257                                native_bt.component_filter_get_input_port_by_index,
 258                                native_bt.component_filter_get_input_port_count)
 259
 260
 261 # This is analogous to _GenericSinkComponentClass, but for sink
 262 # component objects.
 263 class _GenericSinkComponent(object._SharedObject, _SinkComponent):
 264     _get_ref = native_bt.component_sink_get_ref
 265     _put_ref = native_bt.component_sink_put_ref
 266
 267     @property
 268     def input_ports(self):
 269         return _ComponentPorts(False, self,
 270                                native_bt.component_sink_get_input_port_by_name,
 271                                native_bt.component_sink_get_input_port_by_index,
 272                                native_bt.component_sink_get_input_port_count)
 273
 274
 275 _COMP_CLS_TYPE_TO_GENERIC_COMP_PYCLS = {
 276     native_bt.COMPONENT_CLASS_TYPE_SOURCE: _GenericSourceComponent,
 277     native_bt.COMPONENT_CLASS_TYPE_FILTER: _GenericFilterComponent,
 278     native_bt.COMPONENT_CLASS_TYPE_SINK: _GenericSinkComponent,
 279 }
 280
 281
 282 _COMP_CLS_TYPE_TO_GENERIC_COMP_CLS_PYCLS = {
 283     native_bt.COMPONENT_CLASS_TYPE_SOURCE: _GenericSourceComponentClass,
 284     native_bt.COMPONENT_CLASS_TYPE_FILTER: _GenericFilterComponentClass,
 285     native_bt.COMPONENT_CLASS_TYPE_SINK: _GenericSinkComponentClass,
 286 }
 287
 288
 289 # Create a component Python object of type _GenericSourceComponent,
 290 # _GenericFilterComponent or _GenericSinkComponent, depending on
 291 # comp_cls_type.
 292 #
 293 #    Steals the reference to ptr from the caller.
 294
 295 def _create_component_from_ptr(ptr, comp_cls_type):
 296     return _COMP_CLS_TYPE_TO_GENERIC_COMP_PYCLS[comp_cls_type]._create_from_ptr(ptr)
 297
 298 # Create a component class Python object of type
 299 # _GenericSourceComponentClass, _GenericFilterComponentClass or
 300 # _GenericSinkComponentClass, depending on comp_cls_type.
 301 #
 302 # Acquires a new reference to ptr.
 303
 304 def _create_component_class_from_ptr_and_get_ref(ptr, comp_cls_type):
 305     return _COMP_CLS_TYPE_TO_GENERIC_COMP_CLS_PYCLS[comp_cls_type]._create_from_ptr_and_get_ref(ptr)
 306
 307
 308 def _trim_docstring(docstring):
 309     lines = docstring.expandtabs().splitlines()
 310     indent = sys.maxsize
 311
 312     for line in lines[1:]:
 313         stripped = line.lstrip()
 314
 315         if stripped:
 316             indent = min(indent, len(line) - len(stripped))
 317
 318     trimmed = [lines[0].strip()]
 319
 320     if indent < sys.maxsize:
 321         for line in lines[1:]:
 322             trimmed.append(line[indent:].rstrip())
 323
 324     while trimmed and not trimmed[-1]:
 325         trimmed.pop()
 326
 327     while trimmed and not trimmed[0]:
 328         trimmed.pop(0)
 329
 330     return '\n'.join(trimmed)
 331
 332
 333 # Metaclass for component classes defined by Python code.
 334 #
 335 # The Python user can create a standard Python class which inherits one
 336 # of the three base classes (_UserSourceComponent, _UserFilterComponent,
 337 # or _UserSinkComponent). Those base classes set this class
 338 # (_UserComponentType) as their metaclass.
 339 #
 340 # Once the body of a user-defined component class is executed, this
 341 # metaclass is used to create and initialize the class. The metaclass
 342 # creates a native BT component class of the corresponding type and
 343 # associates it with this user-defined class. The metaclass also defines
 344 # class methods like the `name` and `description` properties to match
 345 # the _GenericComponentClass interface.
 346 #
 347 # The component class name which is used is either:
 348 #
 349 # * The `name` parameter of the class:
 350 #
 351 #       class MySink(bt2.SinkComponent, name='my-custom-sink'):
 352 #           ...
 353 #
 354 # * If the `name` class parameter is not used: the name of the class
 355 #   itself (`MySink` in the example above).
 356 #
 357 # The component class description which is used is the user-defined
 358 # class's docstring:
 359 #
 360 #     class MySink(bt2.SinkComponent):
 361 #         'Description goes here'
 362 #         ...
 363 #
 364 # A user-defined Python component class can have an __init__() method
 365 # which must at least accept the `params` and `name` arguments:
 366 #
 367 #     def __init__(self, params, name, something_else):
 368 #         ...
 369 #
 370 # The user-defined component class can also have a _finalize() method
 371 # (do NOT use __del__()) to be notified when the component object is
 372 # finalized.
 373 #
 374 # User-defined source and filter component classes must use the
 375 # `message_iterator_class` class parameter to specify the
 376 # message iterator class to use for this component class:
 377 #
 378 #     class MyMessageIterator(bt2._UserMessageIterator):
 379 #         ...
 380 #
 381 #     class MySource(bt2._UserSourceComponent,
 382 #                    message_iterator_class=MyMessageIterator):
 383 #         ...
 384 #
 385 # This message iterator class must inherit
 386 # bt2._UserMessageIterator, and it must define the _get() and
 387 # _next() methods. The message iterator class can also define an
 388 # __init__() method: this method has access to the original Python
 389 # component object which was used to create it as the `component`
 390 # property. The message iterator class can also define a
 391 # _finalize() method (again, do NOT use __del__()): this is called when
 392 # the message iterator is (really) destroyed.
 393 #
 394 # When the user-defined class is destroyed, this metaclass's __del__()
 395 # method is called: the native BT component class pointer is put (not
 396 # needed anymore, at least not by any Python code since all references
 397 # are dropped for __del__() to be called).
 398 class _UserComponentType(type):
 399     # __new__() is used to catch custom class parameters
 400     def __new__(meta_cls, class_name, bases, attrs, **kwargs):
 401         return super().__new__(meta_cls, class_name, bases, attrs)
 402
 403     def __init__(cls, class_name, bases, namespace, **kwargs):
 404         super().__init__(class_name, bases, namespace)
 405
 406         # skip our own bases; they are never directly instantiated by the user
 407         own_bases = (
 408             '_UserComponent',
 409             '_UserFilterSinkComponent',
 410             '_UserSourceComponent',
 411             '_UserFilterComponent',
 412             '_UserSinkComponent',
 413         )
 414
 415         if class_name in own_bases:
 416             return
 417
 418         comp_cls_name = kwargs.get('name', class_name)
 419         utils._check_str(comp_cls_name)
 420         comp_cls_descr = None
 421         comp_cls_help = None
 422
 423         if hasattr(cls, '__doc__') and cls.__doc__ is not None:
 424             utils._check_str(cls.__doc__)
 425             docstring = _trim_docstring(cls.__doc__)
 426             lines = docstring.splitlines()
 427
 428             if len(lines) >= 1:
 429                 comp_cls_descr = lines[0]
 430
 431             if len(lines) >= 3:
 432                 comp_cls_help = '\n'.join(lines[2:])
 433
 434         iter_cls = kwargs.get('message_iterator_class')
 435
 436         if _UserSourceComponent in bases:
 437             _UserComponentType._set_iterator_class(cls, iter_cls)
 438             cc_ptr = native_bt.py3_component_class_source_create(cls,
 439                                                                  comp_cls_name,
 440                                                                  comp_cls_descr,
 441                                                                  comp_cls_help)
 442         elif _UserFilterComponent in bases:
 443             _UserComponentType._set_iterator_class(cls, iter_cls)
 444             cc_ptr = native_bt.py3_component_class_filter_create(cls,
 445                                                                  comp_cls_name,
 446                                                                  comp_cls_descr,
 447                                                                  comp_cls_help)
 448         elif _UserSinkComponent in bases:
 449             if not hasattr(cls, '_consume'):
 450                 raise bt2.IncompleteUserClass("cannot create component class '{}': missing a _consume() method".format(class_name))
 451
 452             cc_ptr = native_bt.py3_component_class_sink_create(cls,
 453                                                                comp_cls_name,
 454                                                                comp_cls_descr,
 455                                                                comp_cls_help)
 456         else:
 457             raise bt2.IncompleteUserClass("cannot find a known component class base in the bases of '{}'".format(class_name))
 458
 459         if cc_ptr is None:
 460             raise bt2.CreationError("cannot create component class '{}'".format(class_name))
 461
 462         cls._cc_ptr = cc_ptr
 463
 464     def _init_from_native(cls, comp_ptr, params_ptr):
 465         # create instance, not user-initialized yet
 466         self = cls.__new__(cls)
 467
 468         # pointer to native self component object (weak/borrowed)
 469         self._ptr = comp_ptr
 470
 471         # call user's __init__() method
 472         if params_ptr is not None:
 473             params = bt2.value._create_from_ptr_and_get_ref(params_ptr)
 474         else:
 475             params = None
 476
 477         self.__init__(params)
 478         return self
 479
 480     def __call__(cls, *args, **kwargs):
 481         raise bt2.Error('cannot directly instantiate a user component from a Python module')
 482
 483     @staticmethod
 484     def _set_iterator_class(cls, iter_cls):
 485         if iter_cls is None:
 486             raise bt2.IncompleteUserClass("cannot create component class '{}': missing message iterator class".format(cls.__name__))
 487
 488         if not issubclass(iter_cls, bt2.message_iterator._UserMessageIterator):
 489             raise bt2.IncompleteUserClass("cannot create component class '{}': message iterator class does not inherit bt2._UserMessageIterator".format(cls.__name__))
 490
 491         if not hasattr(iter_cls, '__next__'):
 492             raise bt2.IncompleteUserClass("cannot create component class '{}': message iterator class is missing a __next__() method".format(cls.__name__))
 493
 494         cls._iter_cls = iter_cls
 495
 496     @property
 497     def name(cls):
 498         ptr = cls._as_component_class_ptr(cls._cc_ptr)
 499         return native_bt.component_class_get_name(ptr)
 500
 501     @property
 502     def description(cls):
 503         ptr = cls._as_component_class_ptr(cls._cc_ptr)
 504         return native_bt.component_class_get_description(ptr)
 505
 506     @property
 507     def help(cls):
 508         ptr = cls._as_component_class_ptr(cls._cc_ptr)
 509         return native_bt.component_class_get_help(ptr)
 510
 511     @property
 512     def addr(cls):
 513         return int(cls._cc_ptr)
 514
 515     def _query_from_native(cls, query_exec_ptr, obj, params_ptr):
 516         # this can raise, in which case the native call to
 517         # bt_component_class_query() returns NULL
 518         if params_ptr is not None:
 519             params = bt2.value._create_from_ptr_and_get_ref(params_ptr)
 520         else:
 521             params = None
 522
 523         query_exec = bt2.QueryExecutor._create_from_ptr_and_get_ref(
 524             query_exec_ptr)
 525
 526         # this can raise, but the native side checks the exception
 527         results = cls._query(query_exec, obj, params)
 528
 529         # this can raise, but the native side checks the exception
 530         results = bt2.create_value(results)
 531
 532         if results is None:
 533             results_addr = int(native_bt.value_null)
 534         else:
 535             # return new reference
 536             results_addr = int(results._release())
 537
 538         return results_addr
 539
 540     def _query(cls, query_executor, obj, params):
 541         raise NotImplementedError
 542
 543     def _component_class_ptr(self):
 544         return self._as_component_class_ptr(self._cc_ptr)
 545
 546     def __del__(cls):
 547         if hasattr(cls, '_cc_ptr'):
 548             cc_ptr = cls._as_component_class_ptr(cls._cc_ptr)
 549             native_bt.component_class_put_ref(cc_ptr)
 550
 551 # Subclasses must provide these methods or property:
 552 #
 553 #   - _as_not_self_specific_component_ptr: static method, must return the passed
 554 #     specialized self component pointer (e.g. 'bt_self_component_sink *') as a
 555 #     specialized non-self pointer (e.g. 'bt_component_sink *').
 556 #   - _borrow_component_class_ptr: static method, must return a pointer to the
 557 #     specialized component class (e.g. 'bt_component_class_sink *') of the
 558 #     passed specialized component pointer (e.g. 'bt_component_sink *').
 559 #   - _comp_cls_type: property, one of the native_bt.COMPONENT_CLASS_TYPE_*
 560 #     constants.
 561
 562 class _UserComponent(metaclass=_UserComponentType):
 563     @property
 564     def name(self):
 565         ptr = self._as_not_self_specific_component_ptr(self._ptr)
 566         ptr = self._as_component_ptr(ptr)
 567         name = native_bt.component_get_name(ptr)
 568         assert name is not None
 569         return name
 570
 571     @property
 572     def component_class(self):
 573         comp_ptr = self._as_not_self_specific_component_ptr(self._ptr)
 574         cc_ptr = self._borrow_component_class_ptr(comp_ptr)
 575         return _create_component_class_from_ptr_and_get_ref(cc_ptr, self._comp_cls_type)
 576
 577     @property
 578     def addr(self):
 579         return int(self._ptr)
 580
 581     def __init__(self, params=None):
 582         pass
 583
 584     def _finalize(self):
 585         pass
 586
 587     def _accept_port_connection(self, port, other_port):
 588         return True
 589
 590     def _accept_port_connection_from_native(self, port_ptr, other_port_ptr):
 591         native_bt.get(port_ptr)
 592         native_bt.get(other_port_ptr)
 593         port = bt2.port._create_private_from_ptr(port_ptr)
 594         other_port = bt2.port._create_from_ptr(other_port_ptr)
 595         res = self._accept_port_connection(port, other_port_ptr)
 596
 597         if type(res) is not bool:
 598             raise TypeError("'{}' is not a 'bool' object")
 599
 600         return res
 601
 602     def _port_connected(self, port, other_port):
 603         pass
 604
 605     def _port_connected_from_native(self, port_ptr, other_port_ptr):
 606         native_bt.get(port_ptr)
 607         native_bt.get(other_port_ptr)
 608         port = bt2.port._create_private_from_ptr(port_ptr)
 609         other_port = bt2.port._create_from_ptr(other_port_ptr)
 610
 611         try:
 612             self._port_connected(port, other_port)
 613         except:
 614             if not _NO_PRINT_TRACEBACK:
 615                 traceback.print_exc()
 616
 617     def _port_disconnected(self, port):
 618         pass
 619
 620     def _port_disconnected_from_native(self, port_ptr):
 621         native_bt.get(port_ptr)
 622         port = bt2.port._create_private_from_ptr(port_ptr)
 623
 624         try:
 625             self._port_disconnected(port)
 626         except:
 627             if not _NO_PRINT_TRACEBACK:
 628                 traceback.print_exc()
 629
 630
 631 class _UserSourceComponent(_UserComponent, _SourceComponent):
 632     _as_not_self_specific_component_ptr = native_bt.self_component_source_as_component_source
 633
 634     @property
 635     def _output_ports(self):
 636         return _ComponentPorts(True, self,
 637                                native_bt.private_component_source_get_output_private_port_by_name,
 638                                native_bt.private_component_source_get_output_private_port_by_index,
 639                                native_bt.component_source_get_output_port_count)
 640
 641     def _add_output_port(self, name):
 642         utils._check_str(name)
 643         fn = native_bt.private_component_source_add_output_private_port
 644         comp_status, priv_port_ptr = fn(self._ptr, name, None)
 645         _handle_component_status(comp_status,
 646                                  'cannot add output port to source component object')
 647         assert(priv_port_ptr)
 648         return bt2.port._create_private_from_ptr(priv_port_ptr)
 649
 650
 651 class _UserFilterComponent(_UserComponent, _FilterComponent):
 652     _as_not_self_specific_component_ptr = native_bt.self_component_filter_as_component_filter
 653
 654     @property
 655     def _output_ports(self):
 656         return _ComponentPorts(True, self,
 657                                native_bt.private_component_filter_get_output_private_port_by_name,
 658                                native_bt.private_component_filter_get_output_private_port_by_index,
 659                                native_bt.component_filter_get_output_port_count)
 660
 661     @property
 662     def _input_ports(self):
 663         return _ComponentPorts(True, self,
 664                                native_bt.private_component_filter_get_input_private_port_by_name,
 665                                native_bt.private_component_filter_get_input_private_port_by_index,
 666                                native_bt.component_filter_get_input_port_count)
 667
 668     def _add_output_port(self, name):
 669         utils._check_str(name)
 670         fn = native_bt.private_component_filter_add_output_private_port
 671         comp_status, priv_port_ptr = fn(self._ptr, name, None)
 672         _handle_component_status(comp_status,
 673                                  'cannot add output port to filter component object')
 674         assert(priv_port_ptr)
 675         return bt2.port._create_private_from_ptr(priv_port_ptr)
 676
 677     def _add_input_port(self, name):
 678         utils._check_str(name)
 679         fn = native_bt.private_component_filter_add_input_private_port
 680         comp_status, priv_port_ptr = fn(self._ptr, name, None)
 681         _handle_component_status(comp_status,
 682                                  'cannot add input port to filter component object')
 683         assert(priv_port_ptr)
 684         return bt2.port._create_private_from_ptr(priv_port_ptr)
 685
 686
 687 class _UserSinkComponent(_UserComponent, _SinkComponent):
 688     _as_not_self_specific_component_ptr = native_bt.self_component_sink_as_component_sink
 689
 690     @property
 691     def _input_ports(self):
 692         return _ComponentPorts(True, self,
 693                                native_bt.private_component_sink_get_input_private_port_by_name,
 694                                native_bt.private_component_sink_get_input_private_port_by_index,
 695                                native_bt.component_sink_get_input_port_count)
 696
 697     def _add_input_port(self, name):
 698         utils._check_str(name)
 699         fn = native_bt.private_component_sink_add_input_private_port
 700         comp_status, priv_port_ptr = fn(self._ptr, name, None)
 701         _handle_component_status(comp_status,
 702                                  'cannot add input port to sink component object')
 703         assert(priv_port_ptr)
 704         return bt2.port._create_private_from_ptr(priv_port_ptr)