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#
# Copyright (c) 2013, Open Source Robotics Foundation, Inc.
# Copyright (c) 2016, Clearpath Robotics
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# modification, are permitted provided that the following conditions
# are met:
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#    notice, this list of conditions and the following disclaimer.
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#    disclaimer in the documentation and/or other materials provided
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import os
import re
import subprocess

from distutils.version import LooseVersion


class Git(object):
    _client_executable = None
    _client_version = None

    def __init__(self, cwd=None):
        self.cwd = cwd
        if not self._client_executable:
            self.__class__._client_executable = _find_executable('git')

    def command(self, *args):
        assert self._client_executable is not None, "'git' not found"
        return _run_command((self._client_executable,) + args, self.cwd)

    @classmethod
    def version_gte(cls, version):
        if not cls._client_version:
            result = cls().command('--version')
            cls._client_version = result['output'].split()[-1]
        return LooseVersion(cls._client_version) >= LooseVersion(version)


def ref_is_hash(ref):
    return re.match('^[0-9a-f]{40}$', ref) is not None


def _run_command(cmd, cwd=None, env=None):
    result = {'cmd': ' '.join(cmd), 'cwd': cwd}
    try:
        proc = subprocess.Popen(cmd, cwd=cwd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, env=env)
        output, _ = proc.communicate()
        result['output'] = output.rstrip()
        result['returncode'] = proc.returncode
    except subprocess.CalledProcessError as e:
        result['output'] = e.output
        result['returncode'] = e.returncode
    if not isinstance(result['output'], str):
        result['output'] = result['output'].decode('utf-8')
    return result


def _find_executable(file_name):
    pathext = ['']
    if os.name == 'nt':
        # https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/start#remarks
        # mimic the behavior how CMD.exe searching for a command without the extension specified.
        pathext = pathext + os.getenv('PATHEXT').split(os.path.pathsep)
    for path in os.getenv('PATH').split(os.path.pathsep):
        for ext in pathext:
            file_path = os.path.join(path, file_name + ext)
            if os.path.isfile(file_path) and os.access(file_path, os.X_OK):
                return file_path
    return None
