# MIT License
#
# Copyright The SCons Foundation
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be included
# in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
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# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

"""SCons.Tool.gcc

Tool-specific initialization for gcc.

There normally shouldn't be any need to import this module directly.
It will usually be imported through the generic SCons.Tool.Tool()
selection method.

"""

from . import cc
import re
import subprocess

import SCons.Util

compilers = ['gcc', 'cc']


def generate(env):
    """Add Builders and construction variables for gcc to an Environment."""

    if 'CC' not in env:
        env['CC'] = env.Detect(compilers) or compilers[0]

    cc.generate(env)

    if env['PLATFORM'] in ['cygwin', 'win32']:
        env['SHCCFLAGS'] = SCons.Util.CLVar('$CCFLAGS')
    else:
        env['SHCCFLAGS'] = SCons.Util.CLVar('$CCFLAGS -fPIC')
    # determine compiler version
    version = detect_version(env, env['CC'])
    if version:
        env['CCVERSION'] = version


def exists(env):
    # is executable, and is a GNU compiler (or accepts '--version' at least)
    return detect_version(env, env.Detect(env.get('CC', compilers)))


def detect_version(env, cc):
    """Return the version of the GNU compiler, or None if it is not a GNU compiler."""
    version = None
    cc = env.subst(cc)
    if not cc:
        return version

    # -dumpversion was added in GCC 3.0.  As long as we're supporting
    # GCC versions older than that, we should use --version and a
    # regular expression.
    # pipe = SCons.Action._subproc(env, SCons.Util.CLVar(cc) + ['-dumpversion'],
    with SCons.Action._subproc(env, SCons.Util.CLVar(cc) + ['--version'],
                                 stdin='devnull',
                                 stderr='devnull',
                                 stdout=subprocess.PIPE) as pipe:
        if pipe.wait() != 0:
            return version

        # -dumpversion variant:
        # line = pipe.stdout.read().strip()
        # --version variant:
        line = SCons.Util.to_str(pipe.stdout.readline())
        # Non-GNU compiler's output (like AIX xlc's) may exceed the stdout buffer:
        # So continue with reading to let the child process actually terminate.
        # We don't need to know the rest of the data, so don't bother decoding.
        while pipe.stdout.readline():
            pass


    # -dumpversion variant:
    # if line:
    #     version = line
    # --version variant:
    match = re.search(r'[0-9]+(\.[0-9]+)+', line)
    if match:
        version = match.group(0)

    return version

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