# Protocol Buffers - Google's data interchange format # Copyright 2008 Google Inc. All rights reserved. # http://code.google.com/p/protobuf/ # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions are # met: # # * Redistributions of source code must retain the above copyright # notice, this list of conditions and the following disclaimer. # * Redistributions in binary form must reproduce the above # copyright notice, this list of conditions and the following disclaimer # in the documentation and/or other materials provided with the # distribution. # * Neither the name of Google Inc. nor the names of its # contributors may be used to endorse or promote products derived from # this software without specific prior written permission. # # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. """ This module is the central entity that determines which implementation of the API is used. """ __author__ = 'petar@google.com (Petar Petrov)' import os # This environment variable can be used to switch to a certain implementation # of the Python API. Right now only 'python' and 'cpp' are valid values. Any # other value will be ignored. _implementation_type = os.getenv('PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION', 'python') if _implementation_type != 'python': # For now, by default use the pure-Python implementation. # The code below checks if the C extension is available and # uses it if it is available. _implementation_type = 'cpp' ## Determine automatically which implementation to use. #try: # from google.protobuf.internal import cpp_message # _implementation_type = 'cpp' #except ImportError, e: # _implementation_type = 'python' # This environment variable can be used to switch between the two # 'cpp' implementations. Right now only 1 and 2 are valid values. Any # other value will be ignored. _implementation_version_str = os.getenv( 'PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION_VERSION', '1') if _implementation_version_str not in ('1', '2'): raise ValueError( "unsupported PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION_VERSION: '" + _implementation_version_str + "' (supported versions: 1, 2)" ) _implementation_version = int(_implementation_version_str) # Usage of this function is discouraged. Clients shouldn't care which # implementation of the API is in use. Note that there is no guarantee # that differences between APIs will be maintained. # Please don't use this function if possible. def Type(): return _implementation_type # See comment on 'Type' above. def Version(): return _implementation_version