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