material-components_material-components-ios/scripts/temporary_clone_at_ref

#!/bin/bash
#
# Copyright 2016-present the Material Components for iOS authors. 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.

# Clones a copy of this git repository to a specific path and checks out the provided ref.
#
# This script is useful for checking out two versions of the repo for side-by-side comparison
# purposes with tools such as objc-diff.

DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"; pushd $DIR >> /dev/null
MDC_ROOT="$(git rev-parse --show-toplevel | tail -n1)"; popd >> /dev/null

usage() {
  echo "Usage: $0 <path> <ref>"
  echo
  echo "Clones a copy of this git repository to a specific path"
  echo "and checks out the provided ref."
  echo
  echo "Example usage: $0 path v1.0.0"
}

if [ "$#" -lt 2 ]; then
  usage
  exit -1
fi

if [ ! -d "$1" ]; then
  git clone "$MDC_ROOT" "$1" 2> /dev/null || { echo "Failed to clone."; exit 1; }
fi
pushd "$1" >> /dev/null
git fetch >> /dev/null || { echo "Failed to update repo."; exit 1; }
git checkout -q "$2"
popd >> /dev/null