1# Protocol Buffers - Google's data interchange format 2# Copyright 2008 Google Inc. All rights reserved. 3# https://developers.google.com/protocol-buffers/ 4# 5# Redistribution and use in source and binary forms, with or without 6# modification, are permitted provided that the following conditions are 7# met: 8# 9# * Redistributions of source code must retain the above copyright 10# notice, this list of conditions and the following disclaimer. 11# * Redistributions in binary form must reproduce the above 12# copyright notice, this list of conditions and the following disclaimer 13# in the documentation and/or other materials provided with the 14# distribution. 15# * Neither the name of Google Inc. nor the names of its 16# contributors may be used to endorse or promote products derived from 17# this software without specific prior written permission. 18# 19# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 20# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 21# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 22# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 23# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 24# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 25# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 29# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 31"""Determine which implementation of the protobuf API is used in this process. 32""" 33 34import os 35import sys 36import warnings 37 38try: 39 # pylint: disable=g-import-not-at-top 40 from google.protobuf.internal import _api_implementation 41 # The compile-time constants in the _api_implementation module can be used to 42 # switch to a certain implementation of the Python API at build time. 43 _api_version = _api_implementation.api_version 44except ImportError: 45 _api_version = -1 # Unspecified by compiler flags. 46 47if _api_version == 1: 48 raise ValueError('api_version=1 is no longer supported.') 49 50 51_default_implementation_type = ('cpp' if _api_version > 0 else 'python') 52 53 54# This environment variable can be used to switch to a certain implementation 55# of the Python API, overriding the compile-time constants in the 56# _api_implementation module. Right now only 'python' and 'cpp' are valid 57# values. Any other value will be ignored. 58_implementation_type = os.getenv('PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION', 59 _default_implementation_type) 60 61if _implementation_type != 'python': 62 _implementation_type = 'cpp' 63 64if 'PyPy' in sys.version and _implementation_type == 'cpp': 65 warnings.warn('PyPy does not work yet with cpp protocol buffers. ' 66 'Falling back to the python implementation.') 67 _implementation_type = 'python' 68 69 70# Detect if serialization should be deterministic by default 71try: 72 # The presence of this module in a build allows the proto implementation to 73 # be upgraded merely via build deps. 74 # 75 # NOTE: Merely importing this automatically enables deterministic proto 76 # serialization for C++ code, but we still need to export it as a boolean so 77 # that we can do the same for `_implementation_type == 'python'`. 78 # 79 # NOTE2: It is possible for C++ code to enable deterministic serialization by 80 # default _without_ affecting Python code, if the C++ implementation is not in 81 # use by this module. That is intended behavior, so we don't actually expose 82 # this boolean outside of this module. 83 # 84 # pylint: disable=g-import-not-at-top,unused-import 85 from google.protobuf import enable_deterministic_proto_serialization 86 _python_deterministic_proto_serialization = True 87except ImportError: 88 _python_deterministic_proto_serialization = False 89 90 91# Usage of this function is discouraged. Clients shouldn't care which 92# implementation of the API is in use. Note that there is no guarantee 93# that differences between APIs will be maintained. 94# Please don't use this function if possible. 95def Type(): 96 return _implementation_type 97 98 99def _SetType(implementation_type): 100 """Never use! Only for protobuf benchmark.""" 101 global _implementation_type 102 _implementation_type = implementation_type 103 104 105# See comment on 'Type' above. 106def Version(): 107 return 2 108 109 110# For internal use only 111def IsPythonDefaultSerializationDeterministic(): 112 return _python_deterministic_proto_serialization 113