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 = staticmethod(native_bt.component_class_source_get_ref)
  82     _put_ref = staticmethod(native_bt.component_class_source_put_ref)
  83     _as_component_class_ptr = staticmethod(native_bt.component_class_source_as_component_class)
  84
  85
  86 class _GenericFilterComponentClass(_GenericComponentClass):
  87     _get_ref = staticmethod(native_bt.component_class_filter_get_ref)
  88     _put_ref = staticmethod(native_bt.component_class_filter_put_ref)
  89     _as_component_class_ptr = staticmethod(native_bt.component_class_filter_as_component_class)
  90
  91
  92 class _GenericSinkComponentClass(_GenericComponentClass):
  93     _get_ref = staticmethod(native_bt.component_class_sink_get_ref)
  94     _put_ref = staticmethod(native_bt.component_class_sink_put_ref)
  95     _as_component_class_ptr = staticmethod(native_bt.component_class_sink_as_component_class)
  96
  97
  98 def _handle_component_status(status, gen_error_msg):
  99     if status == native_bt.SELF_COMPONENT_STATUS_END:
 100         raise bt2.Stop
 101     elif status == native_bt.SELF_COMPONENT_STATUS_AGAIN:
 102         raise bt2.TryAgain
 103     elif status == native_bt.SELF_COMPONENT_STATUS_REFUSE_PORT_CONNECTION:
 104         raise bt2.PortConnectionRefused
 105     elif status < 0:
 106         raise bt2.Error(gen_error_msg)
 107
 108
 109 class _PortIterator(collections.abc.Iterator):
 110     def __init__(self, comp_ports):
 111         self._comp_ports = comp_ports
 112         self._at = 0
 113
 114     def __next__(self):
 115         if self._at == len(self._comp_ports):
 116             raise StopIteration
 117
 118         comp_ports = self._comp_ports
 119         comp_ptr = comp_ports._component_ptr
 120
 121         port_ptr = comp_ports._borrow_port_ptr_at_index(comp_ptr, self._at)
 122         assert port_ptr is not None
 123
 124         name = native_bt.port_get_name(comp_ports._port_pycls._as_port_ptr(port_ptr))
 125         assert name is not None
 126
 127         self._at += 1
 128         return name
 129
 130
 131 class _ComponentPorts(collections.abc.Mapping):
 132
 133     # component_ptr is a bt_component_source *, bt_component_filter * or
 134     # bt_component_sink *.  Its type must match the type expected by the
 135     # functions passed as arguments.
 136
 137     def __init__(self, component_ptr,
 138                  borrow_port_ptr_by_name,
 139                  borrow_port_ptr_at_index,
 140                  get_port_count,
 141                  port_pycls):
 142         self._component_ptr = component_ptr
 143         self._borrow_port_ptr_by_name = borrow_port_ptr_by_name
 144         self._borrow_port_ptr_at_index = borrow_port_ptr_at_index
 145         self._get_port_count = get_port_count
 146         self._port_pycls = port_pycls
 147
 148     def __getitem__(self, key):
 149         utils._check_str(key)
 150         port_ptr = self._borrow_port_ptr_by_name(self._component_ptr, key)
 151
 152         if port_ptr is None:
 153             raise KeyError(key)
 154
 155         return self._port_pycls._create_from_ptr_and_get_ref(port_ptr)
 156
 157     def __len__(self):
 158         count = self._get_port_count(self._component_ptr)
 159         assert count >= 0
 160         return count
 161
 162     def __iter__(self):
 163         return _PortIterator(self)
 164
 165
 166 # This class holds the methods which are common to both generic
 167 # component objects and Python user component objects.
 168 #
 169 # Subclasses must provide these methods or property:
 170 #
 171 #   - _borrow_component_class_ptr: static method, must return a pointer to the
 172 #     specialized component class (e.g. 'bt_component_class_sink *') of the
 173 #     passed specialized component pointer (e.g. 'bt_component_sink *').
 174 #   - _comp_cls_type: property, one of the native_bt.COMPONENT_CLASS_TYPE_*
 175 #     constants.
 176 #   - _as_component_ptr: static method, must return the passed specialized
 177 #     component pointer (e.g. 'bt_component_sink *') as a 'bt_component *'.
 178
 179 class _Component:
 180     @property
 181     def name(self):
 182         ptr = self._as_component_ptr(self._ptr)
 183         name = native_bt.component_get_name(ptr)
 184         assert name is not None
 185         return name
 186
 187     @property
 188     def component_class(self):
 189         cc_ptr = self._borrow_component_class_ptr(self._ptr)
 190         assert cc_ptr is not None
 191         return _create_component_class_from_ptr_and_get_ref(cc_ptr, self._comp_cls_type)
 192
 193     def __eq__(self, other):
 194         if not hasattr(other, 'addr'):
 195             return False
 196
 197         return self.addr == other.addr
 198
 199
 200 class _SourceComponent(_Component):
 201     _borrow_component_class_ptr = staticmethod(native_bt.component_source_borrow_class_const)
 202     _comp_cls_type = native_bt.COMPONENT_CLASS_TYPE_SOURCE
 203     _as_component_class_ptr = staticmethod(native_bt.component_class_source_as_component_class)
 204     _as_component_ptr = staticmethod(native_bt.component_source_as_component_const)
 205
 206
 207 class _FilterComponent(_Component):
 208     _borrow_component_class_ptr = staticmethod(native_bt.component_filter_borrow_class_const)
 209     _comp_cls_type = native_bt.COMPONENT_CLASS_TYPE_FILTER
 210     _as_component_class_ptr = staticmethod(native_bt.component_class_filter_as_component_class)
 211     _as_component_ptr = staticmethod(native_bt.component_filter_as_component_const)
 212
 213
 214 class _SinkComponent(_Component):
 215     _borrow_component_class_ptr = staticmethod(native_bt.component_sink_borrow_class_const)
 216     _comp_cls_type = native_bt.COMPONENT_CLASS_TYPE_SINK
 217     _as_component_class_ptr = staticmethod(native_bt.component_class_sink_as_component_class)
 218     _as_component_ptr = staticmethod(native_bt.component_sink_as_component_const)
 219
 220
 221 # This is analogous to _GenericSourceComponentClass, but for source
 222 # component objects.
 223 class _GenericSourceComponent(object._SharedObject, _SourceComponent):
 224     _get_ref = staticmethod(native_bt.component_source_get_ref)
 225     _put_ref = staticmethod(native_bt.component_source_put_ref)
 226
 227     @property
 228     def output_ports(self):
 229         return _ComponentPorts(self._ptr,
 230                                native_bt.component_source_borrow_output_port_by_name_const,
 231                                native_bt.component_source_borrow_output_port_by_index_const,
 232                                native_bt.component_source_get_output_port_count,
 233                                bt2.port._OutputPort)
 234
 235
 236 # This is analogous to _GenericFilterComponentClass, but for filter
 237 # component objects.
 238 class _GenericFilterComponent(object._SharedObject, _FilterComponent):
 239     _get_ref = staticmethod(native_bt.component_filter_get_ref)
 240     _put_ref = staticmethod(native_bt.component_filter_put_ref)
 241
 242     @property
 243     def output_ports(self):
 244         return _ComponentPorts(self._ptr,
 245                                native_bt.component_filter_borrow_output_port_by_name_const,
 246                                native_bt.component_filter_borrow_output_port_by_index_const,
 247                                native_bt.component_filter_get_output_port_count,
 248                                bt2.port._OutputPort)
 249
 250     @property
 251     def input_ports(self):
 252         return _ComponentPorts(self._ptr,
 253                                native_bt.component_filter_borrow_input_port_by_name_const,
 254                                native_bt.component_filter_borrow_input_port_by_index_const,
 255                                native_bt.component_filter_get_input_port_count,
 256                                bt2.port._InputPort)
 257
 258
 259 # This is analogous to _GenericSinkComponentClass, but for sink
 260 # component objects.
 261 class _GenericSinkComponent(object._SharedObject, _SinkComponent):
 262     _get_ref = staticmethod(native_bt.component_sink_get_ref)
 263     _put_ref = staticmethod(native_bt.component_sink_put_ref)
 264
 265     @property
 266     def input_ports(self):
 267         return _ComponentPorts(self._ptr,
 268                                native_bt.component_sink_borrow_input_port_by_name_const,
 269                                native_bt.component_sink_borrow_input_port_by_index_const,
 270                                native_bt.component_sink_get_input_port_count,
 271                                bt2.port._InputPort)
 272
 273
 274 _COMP_CLS_TYPE_TO_GENERIC_COMP_PYCLS = {
 275     native_bt.COMPONENT_CLASS_TYPE_SOURCE: _GenericSourceComponent,
 276     native_bt.COMPONENT_CLASS_TYPE_FILTER: _GenericFilterComponent,
 277     native_bt.COMPONENT_CLASS_TYPE_SINK: _GenericSinkComponent,
 278 }
 279
 280
 281 _COMP_CLS_TYPE_TO_GENERIC_COMP_CLS_PYCLS = {
 282     native_bt.COMPONENT_CLASS_TYPE_SOURCE: _GenericSourceComponentClass,
 283     native_bt.COMPONENT_CLASS_TYPE_FILTER: _GenericFilterComponentClass,
 284     native_bt.COMPONENT_CLASS_TYPE_SINK: _GenericSinkComponentClass,
 285 }
 286
 287
 288 # Create a component Python object of type _GenericSourceComponent,
 289 # _GenericFilterComponent or _GenericSinkComponent, depending on
 290 # comp_cls_type.
 291 #
 292 #    Steals the reference to ptr from the caller.
 293
 294 def _create_component_from_ptr(ptr, comp_cls_type):
 295     return _COMP_CLS_TYPE_TO_GENERIC_COMP_PYCLS[comp_cls_type]._create_from_ptr(ptr)
 296
 297 # Create a component class Python object of type
 298 # _GenericSourceComponentClass, _GenericFilterComponentClass or
 299 # _GenericSinkComponentClass, depending on comp_cls_type.
 300 #
 301 # Acquires a new reference to ptr.
 302
 303 def _create_component_class_from_ptr_and_get_ref(ptr, comp_cls_type):
 304     return _COMP_CLS_TYPE_TO_GENERIC_COMP_CLS_PYCLS[comp_cls_type]._create_from_ptr_and_get_ref(ptr)
 305
 306
 307 def _trim_docstring(docstring):
 308     lines = docstring.expandtabs().splitlines()
 309     indent = sys.maxsize
 310
 311     for line in lines[1:]:
 312         stripped = line.lstrip()
 313
 314         if stripped:
 315             indent = min(indent, len(line) - len(stripped))
 316
 317     trimmed = [lines[0].strip()]
 318
 319     if indent < sys.maxsize:
 320         for line in lines[1:]:
 321             trimmed.append(line[indent:].rstrip())
 322
 323     while trimmed and not trimmed[-1]:
 324         trimmed.pop()
 325
 326     while trimmed and not trimmed[0]:
 327         trimmed.pop(0)
 328
 329     return '\n'.join(trimmed)
 330
 331
 332 # Metaclass for component classes defined by Python code.
 333 #
 334 # The Python user can create a standard Python class which inherits one
 335 # of the three base classes (_UserSourceComponent, _UserFilterComponent,
 336 # or _UserSinkComponent). Those base classes set this class
 337 # (_UserComponentType) as their metaclass.
 338 #
 339 # Once the body of a user-defined component class is executed, this
 340 # metaclass is used to create and initialize the class. The metaclass
 341 # creates a native BT component class of the corresponding type and
 342 # associates it with this user-defined class. The metaclass also defines
 343 # class methods like the `name` and `description` properties to match
 344 # the _GenericComponentClass interface.
 345 #
 346 # The component class name which is used is either:
 347 #
 348 # * The `name` parameter of the class:
 349 #
 350 #       class MySink(bt2.SinkComponent, name='my-custom-sink'):
 351 #           ...
 352 #
 353 # * If the `name` class parameter is not used: the name of the class
 354 #   itself (`MySink` in the example above).
 355 #
 356 # The component class description which is used is the user-defined
 357 # class's docstring:
 358 #
 359 #     class MySink(bt2.SinkComponent):
 360 #         'Description goes here'
 361 #         ...
 362 #
 363 # A user-defined Python component class can have an __init__() method
 364 # which must at least accept the `params` and `name` arguments:
 365 #
 366 #     def __init__(self, params, name, something_else):
 367 #         ...
 368 #
 369 # The user-defined component class can also have a _finalize() method
 370 # (do NOT use __del__()) to be notified when the component object is
 371 # finalized.
 372 #
 373 # User-defined source and filter component classes must use the
 374 # `message_iterator_class` class parameter to specify the
 375 # message iterator class to use for this component class:
 376 #
 377 #     class MyMessageIterator(bt2._UserMessageIterator):
 378 #         ...
 379 #
 380 #     class MySource(bt2._UserSourceComponent,
 381 #                    message_iterator_class=MyMessageIterator):
 382 #         ...
 383 #
 384 # This message iterator class must inherit
 385 # bt2._UserMessageIterator, and it must define the _get() and
 386 # _next() methods. The message iterator class can also define an
 387 # __init__() method: this method has access to the original Python
 388 # component object which was used to create it as the `component`
 389 # property. The message iterator class can also define a
 390 # _finalize() method (again, do NOT use __del__()): this is called when
 391 # the message iterator is (really) destroyed.
 392 #
 393 # When the user-defined class is destroyed, this metaclass's __del__()
 394 # method is called: the native BT component class pointer is put (not
 395 # needed anymore, at least not by any Python code since all references
 396 # are dropped for __del__() to be called).
 397 class _UserComponentType(type):
 398     # __new__() is used to catch custom class parameters
 399     def __new__(meta_cls, class_name, bases, attrs, **kwargs):
 400         return super().__new__(meta_cls, class_name, bases, attrs)
 401
 402     def __init__(cls, class_name, bases, namespace, **kwargs):
 403         super().__init__(class_name, bases, namespace)
 404
 405         # skip our own bases; they are never directly instantiated by the user
 406         own_bases = (
 407             '_UserComponent',
 408             '_UserFilterSinkComponent',
 409             '_UserSourceComponent',
 410             '_UserFilterComponent',
 411             '_UserSinkComponent',
 412         )
 413
 414         if class_name in own_bases:
 415             return
 416
 417         comp_cls_name = kwargs.get('name', class_name)
 418         utils._check_str(comp_cls_name)
 419         comp_cls_descr = None
 420         comp_cls_help = None
 421
 422         if hasattr(cls, '__doc__') and cls.__doc__ is not None:
 423             utils._check_str(cls.__doc__)
 424             docstring = _trim_docstring(cls.__doc__)
 425             lines = docstring.splitlines()
 426
 427             if len(lines) >= 1:
 428                 comp_cls_descr = lines[0]
 429
 430             if len(lines) >= 3:
 431                 comp_cls_help = '\n'.join(lines[2:])
 432
 433         iter_cls = kwargs.get('message_iterator_class')
 434
 435         if _UserSourceComponent in bases:
 436             _UserComponentType._set_iterator_class(cls, iter_cls)
 437             cc_ptr = native_bt.py3_component_class_source_create(cls,
 438                                                                  comp_cls_name,
 439                                                                  comp_cls_descr,
 440                                                                  comp_cls_help)
 441         elif _UserFilterComponent in bases:
 442             _UserComponentType._set_iterator_class(cls, iter_cls)
 443             cc_ptr = native_bt.py3_component_class_filter_create(cls,
 444                                                                  comp_cls_name,
 445                                                                  comp_cls_descr,
 446                                                                  comp_cls_help)
 447         elif _UserSinkComponent in bases:
 448             if not hasattr(cls, '_consume'):
 449                 raise bt2.IncompleteUserClass("cannot create component class '{}': missing a _consume() method".format(class_name))
 450
 451             cc_ptr = native_bt.py3_component_class_sink_create(cls,
 452                                                                comp_cls_name,
 453                                                                comp_cls_descr,
 454                                                                comp_cls_help)
 455         else:
 456             raise bt2.IncompleteUserClass("cannot find a known component class base in the bases of '{}'".format(class_name))
 457
 458         if cc_ptr is None:
 459             raise bt2.CreationError("cannot create component class '{}'".format(class_name))
 460
 461         cls._cc_ptr = cc_ptr
 462
 463     def _init_from_native(cls, comp_ptr, params_ptr):
 464         # create instance, not user-initialized yet
 465         self = cls.__new__(cls)
 466
 467         # pointer to native self component object (weak/borrowed)
 468         self._ptr = comp_ptr
 469
 470         # call user's __init__() method
 471         if params_ptr is not None:
 472             params = bt2.value._create_from_ptr_and_get_ref(params_ptr)
 473         else:
 474             params = None
 475
 476         self.__init__(params)
 477         return self
 478
 479     def __call__(cls, *args, **kwargs):
 480         raise bt2.Error('cannot directly instantiate a user component from a Python module')
 481
 482     @staticmethod
 483     def _set_iterator_class(cls, iter_cls):
 484         if iter_cls is None:
 485             raise bt2.IncompleteUserClass("cannot create component class '{}': missing message iterator class".format(cls.__name__))
 486
 487         if not issubclass(iter_cls, bt2.message_iterator._UserMessageIterator):
 488             raise bt2.IncompleteUserClass("cannot create component class '{}': message iterator class does not inherit bt2._UserMessageIterator".format(cls.__name__))
 489
 490         if not hasattr(iter_cls, '__next__'):
 491             raise bt2.IncompleteUserClass("cannot create component class '{}': message iterator class is missing a __next__() method".format(cls.__name__))
 492
 493         cls._iter_cls = iter_cls
 494
 495     @property
 496     def name(cls):
 497         ptr = cls._as_component_class_ptr(cls._cc_ptr)
 498         return native_bt.component_class_get_name(ptr)
 499
 500     @property
 501     def description(cls):
 502         ptr = cls._as_component_class_ptr(cls._cc_ptr)
 503         return native_bt.component_class_get_description(ptr)
 504
 505     @property
 506     def help(cls):
 507         ptr = cls._as_component_class_ptr(cls._cc_ptr)
 508         return native_bt.component_class_get_help(ptr)
 509
 510     @property
 511     def addr(cls):
 512         return int(cls._cc_ptr)
 513
 514     def _query_from_native(cls, query_exec_ptr, obj, params_ptr):
 515         # this can raise, in which case the native call to
 516         # bt_component_class_query() returns NULL
 517         if params_ptr is not None:
 518             params = bt2.value._create_from_ptr_and_get_ref(params_ptr)
 519         else:
 520             params = None
 521
 522         query_exec = bt2.QueryExecutor._create_from_ptr_and_get_ref(
 523             query_exec_ptr)
 524
 525         # this can raise, but the native side checks the exception
 526         results = cls._query(query_exec, obj, params)
 527
 528         # this can raise, but the native side checks the exception
 529         results = bt2.create_value(results)
 530
 531         if results is None:
 532             results_addr = int(native_bt.value_null)
 533         else:
 534             # return new reference
 535             results_addr = int(results._release())
 536
 537         return results_addr
 538
 539     def _query(cls, query_executor, obj, params):
 540         raise NotImplementedError
 541
 542     def _component_class_ptr(self):
 543         return self._as_component_class_ptr(self._cc_ptr)
 544
 545     def __del__(cls):
 546         if hasattr(cls, '_cc_ptr'):
 547             cc_ptr = cls._as_component_class_ptr(cls._cc_ptr)
 548             native_bt.component_class_put_ref(cc_ptr)
 549
 550 # Subclasses must provide these methods or property:
 551 #
 552 #   - _as_not_self_specific_component_ptr: static method, must return the passed
 553 #     specialized self component pointer (e.g. 'bt_self_component_sink *') as a
 554 #     specialized non-self pointer (e.g. 'bt_component_sink *').
 555 #   - _borrow_component_class_ptr: static method, must return a pointer to the
 556 #     specialized component class (e.g. 'bt_component_class_sink *') of the
 557 #     passed specialized component pointer (e.g. 'bt_component_sink *').
 558 #   - _comp_cls_type: property, one of the native_bt.COMPONENT_CLASS_TYPE_*
 559 #     constants.
 560
 561 class _UserComponent(metaclass=_UserComponentType):
 562     @property
 563     def name(self):
 564         ptr = self._as_not_self_specific_component_ptr(self._ptr)
 565         ptr = self._as_component_ptr(ptr)
 566         name = native_bt.component_get_name(ptr)
 567         assert name is not None
 568         return name
 569
 570     @property
 571     def component_class(self):
 572         comp_ptr = self._as_not_self_specific_component_ptr(self._ptr)
 573         cc_ptr = self._borrow_component_class_ptr(comp_ptr)
 574         return _create_component_class_from_ptr_and_get_ref(cc_ptr, self._comp_cls_type)
 575
 576     @property
 577     def addr(self):
 578         return int(self._ptr)
 579
 580     def __init__(self, params=None):
 581         pass
 582
 583     def _finalize(self):
 584         pass
 585
 586     def _accept_port_connection(self, port, other_port):
 587         return True
 588
 589     def _accept_port_connection_from_native(self, self_port_ptr, self_port_type, other_port_ptr):
 590         port = bt2.port._create_self_from_ptr_and_get_ref(
 591             self_port_ptr, self_port_type)
 592
 593         if self_port_type == native_bt.PORT_TYPE_OUTPUT:
 594             other_port_type = native_bt.PORT_TYPE_INPUT
 595         else:
 596             other_port_type = native_bt.PORT_TYPE_OUTPUT
 597
 598         other_port = bt2.port._create_from_ptr_and_get_ref(
 599             other_port_ptr, other_port_type)
 600         res = self._accept_port_connection(port, other_port_ptr)
 601
 602         if type(res) is not bool:
 603             raise TypeError("'{}' is not a 'bool' object")
 604
 605         return res
 606
 607     def _port_connected(self, port, other_port):
 608         pass
 609
 610     def _port_connected_from_native(self, self_port_ptr, self_port_type, other_port_ptr):
 611         port = bt2.port._create_self_from_ptr_and_get_ref(
 612             self_port_ptr, self_port_type)
 613
 614         if self_port_type == native_bt.PORT_TYPE_OUTPUT:
 615             other_port_type = native_bt.PORT_TYPE_INPUT
 616         else:
 617             other_port_type = native_bt.PORT_TYPE_OUTPUT
 618
 619         other_port = bt2.port._create_from_ptr_and_get_ref(
 620             other_port_ptr, other_port_type)
 621         self._port_connected(port, other_port)
 622
 623     def _create_trace_class(self, env=None, uuid=None,
 624                             assigns_automatic_stream_class_id=True):
 625         ptr = self._as_self_component_ptr(self._ptr)
 626         tc_ptr = native_bt.trace_class_create(ptr)
 627
 628         if tc_ptr is None:
 629             raise bt2.CreationError('could not create trace class')
 630
 631         tc = bt2.TraceClass._create_from_ptr(tc_ptr)
 632
 633         if env is not None:
 634             for key, value in env.items():
 635                 tc.env[key] = value
 636
 637         if uuid is not None:
 638             tc._uuid = uuid
 639
 640         tc._assigns_automatic_stream_class_id = assigns_automatic_stream_class_id
 641
 642         return tc
 643
 644     def _create_clock_class(self, frequency=None, name=None, description=None,
 645                             precision=None, offset=None, origin_is_unix_epoch=True,
 646                             uuid=None):
 647         ptr = self._as_self_component_ptr(self._ptr)
 648         cc_ptr = native_bt.clock_class_create(ptr)
 649
 650         if cc_ptr is None:
 651             raise bt2.CreationError('could not create clock class')
 652
 653         cc = bt2.clock_class._ClockClass._create_from_ptr(cc_ptr)
 654
 655         if frequency is not None:
 656             cc._frequency = frequency
 657
 658         if name is not None:
 659             cc._name = name
 660
 661         if description is not None:
 662             cc._description = description
 663
 664         if precision is not None:
 665             cc._precision = precision
 666
 667         if offset is not None:
 668             cc._offset = offset
 669
 670         cc._origin_is_unix_epoch = origin_is_unix_epoch
 671
 672         if uuid is not None:
 673             cc._uuid = uuid
 674
 675         return cc
 676
 677
 678 class _UserSourceComponent(_UserComponent, _SourceComponent):
 679     _as_not_self_specific_component_ptr = staticmethod(native_bt.self_component_source_as_component_source)
 680     _as_self_component_ptr = staticmethod(native_bt.self_component_source_as_self_component)
 681
 682     @property
 683     def _output_ports(self):
 684         def get_output_port_count(self_ptr):
 685             ptr = self._as_not_self_specific_component_ptr(self_ptr)
 686             return native_bt.component_source_get_output_port_count(ptr)
 687
 688         return _ComponentPorts(self._ptr,
 689                                native_bt.self_component_source_borrow_output_port_by_name,
 690                                native_bt.self_component_source_borrow_output_port_by_index,
 691                                get_output_port_count,
 692                                bt2.port._UserComponentOutputPort)
 693
 694     def _add_output_port(self, name):
 695         utils._check_str(name)
 696         fn = native_bt.self_component_source_add_output_port
 697         comp_status, self_port_ptr = fn(self._ptr, name, None)
 698         _handle_component_status(comp_status,
 699                                  'cannot add output port to source component object')
 700         assert self_port_ptr is not None
 701         return bt2.port._UserComponentOutputPort._create_from_ptr(self_port_ptr)
 702
 703
 704 class _UserFilterComponent(_UserComponent, _FilterComponent):
 705     _as_not_self_specific_component_ptr = staticmethod(native_bt.self_component_filter_as_component_filter)
 706     _as_self_component_ptr = staticmethod(native_bt.self_component_filter_as_self_component)
 707
 708     @property
 709     def _output_ports(self):
 710         def get_output_port_count(self_ptr):
 711             ptr = self._as_not_self_specific_component_ptr(self_ptr)
 712             return native_bt.component_filter_get_output_port_count(ptr)
 713
 714         return _ComponentPorts(self._ptr,
 715                                native_bt.self_component_filter_borrow_output_port_by_name,
 716                                native_bt.self_component_filter_borrow_output_port_by_index,
 717                                get_output_port_count,
 718                                bt2.port._UserComponentOutputPort)
 719
 720     @property
 721     def _input_ports(self):
 722         def get_input_port_count(self_ptr):
 723             ptr = self._as_not_self_specific_component_ptr(self_ptr)
 724             return native_bt.component_filter_get_input_port_count(ptr)
 725
 726         return _ComponentPorts(self._ptr,
 727                                native_bt.self_component_filter_borrow_input_port_by_name,
 728                                native_bt.self_component_filter_borrow_input_port_by_index,
 729                                get_input_port_count,
 730                                bt2.port._UserComponentInputPort)
 731
 732     def _add_output_port(self, name):
 733         utils._check_str(name)
 734         fn = native_bt.self_component_filter_add_output_port
 735         comp_status, self_port_ptr = fn(self._ptr, name, None)
 736         _handle_component_status(comp_status,
 737                                  'cannot add output port to filter component object')
 738         assert self_port_ptr
 739         return bt2.port._UserComponentOutputPort._create_from_ptr(self_port_ptr)
 740
 741     def _add_input_port(self, name):
 742         utils._check_str(name)
 743         fn = native_bt.self_component_filter_add_input_port
 744         comp_status, self_port_ptr = fn(self._ptr, name, None)
 745         _handle_component_status(comp_status,
 746                                  'cannot add input port to filter component object')
 747         assert self_port_ptr
 748         return bt2.port._UserComponentInputPort._create_from_ptr(self_port_ptr)
 749
 750
 751 class _UserSinkComponent(_UserComponent, _SinkComponent):
 752     _as_not_self_specific_component_ptr = staticmethod(native_bt.self_component_sink_as_component_sink)
 753     _as_self_component_ptr = staticmethod(native_bt.self_component_sink_as_self_component)
 754
 755     @property
 756     def _input_ports(self):
 757         def get_input_port_count(self_ptr):
 758             ptr = self._as_not_self_specific_component_ptr(self_ptr)
 759             return native_bt.component_sink_get_input_port_count(ptr)
 760
 761         return _ComponentPorts(self._ptr,
 762                                native_bt.self_component_sink_borrow_input_port_by_name,
 763                                native_bt.self_component_sink_borrow_input_port_by_index,
 764                                get_input_port_count,
 765                                bt2.port._UserComponentInputPort)
 766
 767     def _add_input_port(self, name):
 768         utils._check_str(name)
 769         fn = native_bt.self_component_sink_add_input_port
 770         comp_status, priv_port_ptr = fn(self._ptr, name, None)
 771         _handle_component_status(comp_status,
 772                                  'cannot add input port to sink component object')
 773         assert priv_port_ptr
 774         return bt2.port._UserComponentInputPort._create_from_ptr(priv_port_ptr)