clang-format-pre-commit-hook

#!/usr/bin/env bash

config=$(git config couchbase.clangformat)

has_issues () {
    diff=$(git clang-format --diff)
    [[ $diff == diff* ]]
}

reformat () {
    if [ ! $config = "commit" ] ; then
        echo -n "Commit rejected. "
    fi
    echo "Running \`git clang-format\` to fix style..."
    reformat_results=$(git clang-format)
    ret_val=$?
    echo "$reformat_results"
    return $ret_val
}

add_reformatted_files () {
    # Hacky. Skips the first line of the output from clang-format,
    # strips leading spaces, and replaces newlines with nulls, to
    # pass to xargs -0 (because xargs -d is a GNU extension)
    # to stage all changes. Better ways would be appreciated!
    echo "$reformat_results" | tail -n +2 | sed -e 's/^[[:space:]]*//' | tr '\n' '\0' | xargs -0 git add
}

if has_issues ; then
    case $config in
      (fix)
        reformat
        if [ $? = 0 ] ; then
            echo "Review changes, add, and commit again."
        fi
        exit 1
        ;;
      (stage)
        reformat
        if [ $? = 0 ] ; then
            add_reformatted_files
        fi
        exit 1
        ;;
      (commit)
        reformat
        if [ $? = 0 ] ; then
            add_reformatted_files
            exit 0
        fi
        exit 1
        ;;
      (*)
        echo "Commit rejected as clang-format detected formatting issues."
        echo "    Run \`git clang-format --diff\` to view suggested changes"
        echo "    and \`git clang-format\` to apply them."
        echo "    Alternatively, use \`git commit --no-verify\` to skip hooks."
        exit 1
        ;;
    esac
fi