bindings/python/bt2/bt2/query_executor.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.component
  25 import bt2
  26
  27
  28 class QueryExecutor(object._SharedObject):
  29     _get_ref = staticmethod(native_bt.query_executor_get_ref)
  30     _put_ref = staticmethod(native_bt.query_executor_put_ref)
  31
  32     def _handle_status(self, status, gen_error_msg):
  33         if status == native_bt.QUERY_EXECUTOR_STATUS_AGAIN:
  34             raise bt2.TryAgain
  35         elif status == native_bt.QUERY_EXECUTOR_STATUS_CANCELED:
  36             raise bt2.QueryExecutorCanceled
  37         elif status == native_bt.QUERY_EXECUTOR_STATUS_INVALID_OBJECT:
  38             raise bt2.InvalidQueryObject
  39         elif status == native_bt.QUERY_EXECUTOR_STATUS_INVALID_PARAMS:
  40             raise bt2.InvalidQueryParams
  41         elif status < 0:
  42             raise bt2.Error(gen_error_msg)
  43
  44     def __init__(self):
  45         ptr = native_bt.query_executor_create()
  46
  47         if ptr is None:
  48             raise bt2.CreationError('cannot create query executor object')
  49
  50         super().__init__(ptr)
  51
  52     def cancel(self):
  53         status = native_bt.query_executor_cancel(self._ptr)
  54         self._handle_status(status, 'cannot cancel query executor object')
  55
  56     @property
  57     def is_canceled(self):
  58         is_canceled = native_bt.query_executor_is_canceled(self._ptr)
  59         assert(is_canceled >= 0)
  60         return is_canceled > 0
  61
  62     def query(self, component_class, object, params=None):
  63         if self.is_canceled:
  64             raise bt2.QueryExecutorCanceled
  65
  66         if not isinstance(component_class, bt2.component._GenericComponentClass):
  67             err = False
  68
  69             try:
  70                 if not issubclass(component_class, bt2.component._UserComponent):
  71                     err = True
  72             except TypeError:
  73                 err = True
  74
  75             if err:
  76                 o = component_class
  77                 raise TypeError("'{}' is not a component class object".format(o))
  78
  79         utils._check_str(object)
  80
  81         if params is None:
  82             params_ptr = native_bt.value_null
  83         else:
  84             params = bt2.create_value(params)
  85             params_ptr = params._ptr
  86
  87         cc_ptr = component_class._component_class_ptr()
  88
  89         status, result_ptr = native_bt.query_executor_query(self._ptr, cc_ptr,
  90                                                             object, params_ptr)
  91         self._handle_status(status, 'cannot query component class')
  92         assert(result_ptr)
  93         return bt2.value._create_from_ptr(result_ptr)