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 _handle_status(self, status, gen_error_msg):
  32         if status == native_bt.MESSAGE_ITERATOR_STATUS_CANCELED:
  33             raise bt2.MessageIteratorCanceled
  34         elif status == native_bt.MESSAGE_ITERATOR_STATUS_AGAIN:
  35             raise bt2.TryAgain
  36         elif status == native_bt.MESSAGE_ITERATOR_STATUS_END:
  37             raise bt2.Stop
  38         elif status == native_bt.MESSAGE_ITERATOR_STATUS_UNSUPPORTED:
  39             raise bt2.UnsupportedFeature
  40         elif status < 0:
  41             raise bt2.Error(gen_error_msg)
  42
  43     def __next__(self):
  44         raise NotImplementedError
  45
  46
  47 class _GenericMessageIterator(object._Object, _MessageIterator):
  48     def _get_msg(self):
  49         msg_ptr = native_bt.message_iterator_get_message(self._ptr)
  50         utils._handle_ptr(msg_ptr, "cannot get message iterator object's current message object")
  51         return bt2.message._create_from_ptr(msg_ptr)
  52
  53     def _next(self):
  54         status = native_bt.message_iterator_next(self._ptr)
  55         self._handle_status(status,
  56                             'unexpected error: cannot advance the message iterator')
  57
  58     def __next__(self):
  59         self._next()
  60         return self._get_msg()
  61
  62
  63 class _PrivateConnectionMessageIterator(_GenericMessageIterator):
  64     @property
  65     def component(self):
  66         comp_ptr = native_bt.private_connection_message_iterator_get_component(self._ptr)
  67         assert(comp_ptr)
  68         return bt2.component._create_generic_component_from_ptr(comp_ptr)
  69
  70
  71 class _OutputPortMessageIterator(_GenericMessageIterator):
  72     pass
  73
  74
  75 class _UserMessageIterator(_MessageIterator):
  76     def __new__(cls, ptr):
  77         # User iterator objects are always created by the native side,
  78         # that is, never instantiated directly by Python code.
  79         #
  80         # The native code calls this, then manually calls
  81         # self.__init__() without the `ptr` argument. The user has
  82         # access to self.component during this call, thanks to this
  83         # self._ptr argument being set.
  84         #
  85         # self._ptr is NOT owned by this object here, so there's nothing
  86         # to do in __del__().
  87         self = super().__new__(cls)
  88         self._ptr = ptr
  89         return self
  90
  91     def __init__(self):
  92         pass
  93
  94     @property
  95     def _component(self):
  96         return native_bt.py3_get_user_component_from_user_msg_iter(self._ptr)
  97
  98     @property
  99     def addr(self):
 100         return int(self._ptr)
 101
 102     def _finalize(self):
 103         pass
 104
 105     def __next__(self):
 106         raise bt2.Stop
 107
 108     def _next_from_native(self):
 109         # this can raise anything: it's catched by the native part
 110         try:
 111             msg = next(self)
 112         except StopIteration:
 113             raise bt2.Stop
 114         except:
 115             raise
 116
 117         utils._check_type(msg, bt2.message._Message)
 118
 119         # take a new reference for the native part
 120         msg._get()
 121         return int(msg._ptr)