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Diffstat (limited to 'python/google/protobuf/internal/api_implementation.py')
-rwxr-xr-x | python/google/protobuf/internal/api_implementation.py | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/python/google/protobuf/internal/api_implementation.py b/python/google/protobuf/internal/api_implementation.py new file mode 100755 index 0000000..f7926c1 --- /dev/null +++ b/python/google/protobuf/internal/api_implementation.py @@ -0,0 +1,89 @@ +# Protocol Buffers - Google's data interchange format +# Copyright 2008 Google Inc. All rights reserved. +# https://developers.google.com/protocol-buffers/ +# +# 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. + +"""Determine which implementation of the protobuf API is used in this process. +""" + +import os +import sys + +try: + # pylint: disable=g-import-not-at-top + from google.protobuf.internal import _api_implementation + # The compile-time constants in the _api_implementation module can be used to + # switch to a certain implementation of the Python API at build time. + _api_version = _api_implementation.api_version + del _api_implementation +except ImportError: + _api_version = 0 + +_default_implementation_type = ( + 'python' if _api_version == 0 else 'cpp') +_default_version_str = ( + '1' if _api_version <= 1 else '2') + +# This environment variable can be used to switch to a certain implementation +# of the Python API, overriding the compile-time constants in the +# _api_implementation module. Right now only 'python' and 'cpp' are valid +# values. Any other value will be ignored. +_implementation_type = os.getenv('PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION', + _default_implementation_type) + +if _implementation_type != 'python': + _implementation_type = 'cpp' + +# This environment variable can be used to switch between the two +# 'cpp' implementations, overriding the compile-time constants in the +# _api_implementation module. 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', + _default_version_str) + +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 |