ggrbm

#!/bin/bash

me=`basename $0`

usage () {
    # Call as: usage [EXITCODE] [USAGE MESSAGE]
    exit_code=1
    if [[ "$1" == [0-9] ]]; then
        exit_code="$1"
        shift
    fi

    cat <<EOF >&2
Usage: $me [options] [BRANCH-CONFIG]

BRANCH-CONFIG defaults to $wd/.git/topic-branches and takes the
format:

    # Comments are allowed
    # Each line contains a set of arguments to pass to git rebase
    # e.g.
    trunk myroot
    myroot mytopic1
    myroot mytopic2

    # You can use arbitrary git commands by prefixing with '!':
    !branch -f working mytopic1
    !merge --no-edit mytopic2

Options:

  -i   Do interactive rebase
EOF

    if [ -n "$1" ]; then
        echo "$*" >&2
        echo
    fi

    exit $exit_code
}

parse_opts () {
    while [ $# != 0 ]; do
        case "$1" in
            -h|--help)
                usage 0
                ;;
            -i)
                interactive=-i
                shift
                ;;
            -*)
                usage "Unrecognised option: $1"
                ;;
            *)
                break
                ;;
        esac
    done

    if [ "$#" -gt 1 ]; then
        usage
    elif [ "$#" -eq 1 ]; then
        conf="$1"
        shift
    elif [ "$#" -eq 0 ]; then
        conf="$root/.git/topic-branches"
    fi

    if ! [ -e "$conf" ]; then
        die "$conf not found; aborting."
    fi

    ARGV=( "$@" )
}

die () {
    echo >&2 "$*"
    exit 1
}

process_line () {
    case "${args[0]}" in
        !*)
            args[0]="${args[0]#!}"
            process_arbitrary_git_command
            ;;
        *)
            process_rebase_command
            ;;
    esac
}

process_arbitrary_git_command () {
    echo "git ${args[*]}"

    if ! git "${args[@]}"; then
        had_issues=y
        echo "git ${args[*]} failed"
        echo "Please fix and then exit shell."
        bash <&3
    fi
}

process_rebase_command () {
    range="${args[0]}..${args[1]}"

    check_whitespace
    echo
    rebase_until_success
    echo
    if [ -z "$had_issues" ]; then
        echo -n "git rebase ${args[*]} done"
    else
        echo -n "git rebase ${args[*]} done; hit enter to continue ... "
        read <&3
    fi
    echo
    div
}

check_whitespace () {
    echo "Checking for whitespace errors in $range"
    if ! ggdcm "$range"; then
        echo -n "Hit enter to continue regardless ... "
        read <&3
        echo
    fi
}

rebase_until_success () {
    echo "git rebase $interactive ${args[*]}"
    had_issues=
    if ! git rebase $interactive "${args[@]}"; then
        had_issues=y
        while [ -e "$root/.git/rebase-apply" ] || [ -d "$root/.git/rebase-merge" ]; do
            echo
            echo "git rebase ${args[@]} not completed."
            echo "Please fix via git rebase --continue / --abort then exit shell."
            bash <&3
        done
    fi
}

restore_head () {
    if [ -n "$orig_head" ]; then
        echo "Checking out original HEAD ($orig_head) ... "
        git checkout "$orig_head"
    else
        echo "WARNING: Couldn't determine original HEAD; current HEAD is probably different".
    fi
}

main () {
    root="`git root`"
    if [ -z "$root" ]; then
        die "git root failed; aborting."
    fi

    if ! which div >&/dev/null; then
        die "div not found on \$PATH; please get from: https://github.com/aspiers/shell-env/blob/master/bin/div"
    fi

    parse_opts "$@"

    if [ -e "$root/.git/rebase-apply" ]; then
        die "$me: rebase already in progress! aborting."
    fi

    orig_head=`git head`

    exec 3>&0 # save STDIN tty
    grep -Ev '^ *(#|$)' "$conf" | while read -a args; do
        process_line
    done

    echo
    restore_head
}

main "$@"