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# -*- sh-basic-offset: 2 -*-
##
# Copyright (c) 2005-2016 Apple Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
##
find_cmd () {
local cmd="$1"; shift;
local path="$(type "${cmd}" 2>/dev/null | sed "s|^${cmd} is \(a tracked alias for \)\{0,1\}||")";
if [ -z "${cmd}" ]; then
return 1;
fi;
echo "${path}";
}
# Echo the major.minor version of the given Python interpreter.
py_version () {
local python="$1"; shift;
echo "$("${python}" -c "from distutils.sysconfig import get_python_version; print get_python_version()")";
}
#
# Test if a particular python interpreter is available, given the full path to
# that interpreter.
#
try_python () {
local python="$1"; shift;
if [ -z "${python}" ]; then
return 1;
fi;
if ! type "${python}" > /dev/null 2>&1; then
return 1;
fi;
local py_version="$(py_version "${python}")";
if [ "$(echo "${py_version}" | sed 's|\.||')" -lt "25" ]; then
return 1;
fi;
return 0;
}
#
# Detect which version of Python to use, then print out which one was detected.
#
# This will prefer the python interpreter in the PYTHON environment variable.
# If that's not found, it will check for "python2.7" and "python", looking for
# each in your PATH.
#
detect_python_version () {
local v;
local p;
for v in "2.7" ""
do
for p in \
"${PYTHON:=}" \
"python${v}" \
;
do
if p="$(find_cmd "${p}")"; then
if try_python "${p}"; then
echo "${p}";
return 0;
fi;
fi;
done;
done;
return 1;
}
#
# Compare version numbers
#
cmp_version () {
local v="$1"; shift;
local mv="$1"; shift;
local vh;
local mvh;
local result;
while true; do
vh="${v%%.*}"; # Get highest-order segment
mvh="${mv%%.*}";
if [ "${vh}" -gt "${mvh}" ]; then
result=1;
break;
fi;
if [ "${vh}" -lt "${mvh}" ]; then
result=0;
break;
fi;
if [ "${v}" = "${v#*.}" ]; then
# No dots left, so we're ok
result=0;
break;
fi;
if [ "${mv}" = "${mv#*.}" ]; then
# No dots left, so we're not gonna match
result=1;
break;
fi;
v="${v#*.}";
mv="${mv#*.}";
done;
return ${result};
}
#
# Detect which python to use, and store it in the 'python' variable, as well as
# setting up variables related to version and build configuration.
#
init_py () {
# First, detect the appropriate version of Python to use, based on our version
# requirements and the environment. Note that all invocations of python in
# our build scripts should therefore be '"${python}"', not 'python'; this is
# important on systems with older system pythons (2.4 or earlier) with an
# alternate install of Python, or alternate python installation mechanisms
# like virtualenv.
bootstrap_python="$(detect_python_version)";
# Set the $PYTHON environment variable to an absolute path pointing at the
# appropriate python executable, a standard-ish mechanism used by certain
# non-distutils things that need to find the "right" python. For instance,
# the part of the PostgreSQL build process which builds pl_python. Note that
# detect_python_version, above, already honors $PYTHON, so if this is already
# set it won't be stomped on, it will just be re-set to the same value.
export PYTHON="$(find_cmd ${bootstrap_python})";
if [ -z "${bootstrap_python:-}" ]; then
echo "No suitable python found. Python 2.6 or 2.7 is required.";
exit 1;
fi;
}
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