git-su - switches user and sshCommand in the current repository

git-su

#!/bin/bash
#
# git-su - Git Switch User
# ========================
#
# git-su switches user and sshCommand in the current repository.
#
# USAGE
# -----
#
#     git su <-l|--list>
#     git su <name>
#     git su <name> <git_subcommand> <args...>
#
#     e.g.  git su -l
#           git su foo
#           git su foo clone $REPO
#
# git-su sets user.name and user.email by the following command.
# ("Foo" and "foo@example.com" are predefined values)
#
#     git config user.name "Foo"
#     git config user.email "foo@example.com"
#     git config core.sshCommand "ssh -i ~/.ssh/foo_rsa"
#
# You can use the third form for init/clone and set user at one command.
#
#
# DEFINITION FILE
# ---------------
#
#     The location of the definition file is '$HOME/.gitsu'. Or You can
#     specify the path using $GIT_SU_CONF environment variable.
#     Alternatively, you can put definitions into $HOME/.gitconfig directly.
#
#     Definition format:
#     ------------------------------
#     [su "name"]
#       name = "Your name"
#       email = "Your email address"
#       sshCommand = "ssh -i ~/.ssh/id_rsa"
#     ------------------------------
#     `name` and `email` are mandatory, `sshCommand` is optional.
#
#     for example:
#     ------------------------------
#     [su "alice"]
#       name = "Alice"
#       email = "alice@example.com"
#
#     [su "bob"]
#       name = "Bob"
#       email = "bob@example.com"
#       sshCommand = "ssh -i ~/.ssh/bob_rsa"
#     ------------------------------
#
#
# LICENSE
# -------
# MIT License
#
#
# AUTHOR
# -------
#
# Yuki <paselan@gmail.com>
#

GIT_SU_CONF=${GIT_SU_CONF:-$HOME/.gitsu}
PROGNAME=$(basename "$0")

if [[ -n "$1" ]]; then
    SU_NAME=$1
else
    echo -e "usage: git su <name> [git-subcommand <args>]" 1>&2
    exit 1
fi

GIT_VERSION=$(git --version | cut -d" " -f 3)

# from: https://stackoverflow.com/questions/4023830/how-to-compare-two-strings-in-dot-separated-version-format-in-bash
vercomp () {
    if [[ $1 == $2 ]]
    then
        return 0
    fi
    local IFS=.
    local i ver1=($1) ver2=($2)
    # fill empty fields in ver1 with zeros
    for ((i=${#ver1[@]}; i<${#ver2[@]}; i++))
    do
        ver1[i]=0
    done
    for ((i=0; i<${#ver1[@]}; i++))
    do
        if [[ -z ${ver2[i]} ]]
        then
            # fill empty fields in ver2 with zeros
            ver2[i]=0
        fi
        if ((10#${ver1[i]} > 10#${ver2[i]}))
        then
            return 1
        fi
        if ((10#${ver1[i]} < 10#${ver2[i]}))
        then
            return 2
        fi
    done
    return 0
}

extract_repo_dir() {
    local dir=${@:$#}

    [[ -d "$dir" ]] && echo "$dir" && return

    dir="${dir##*/}"
    [[ -d "$dir" ]] && echo "$dir" && return

    dir="${dir%.git}"
    [[ -d "$dir" ]] && echo "$dir" && return

    pwd
}

print_su_list()
{
    git config --name-only --get-regexp '^su\..+\.name$' | sed -e 's/^su\.\(.\+\)\.name$/\1/'
}

get_config()
{
    local key=$1

    if [[ -e "$GIT_SU_CONF" ]]; then
        git config --file "$GIT_SU_CONF" --get "$key" 2>/dev/null && return
    fi
    git config --get "$key" 2>/dev/null && return
    return 1
}

apply_su()
{
    local SU_NAME=$1
    local USER_NAME USER_EMAIL CORE_SSH_COMMAND

    if [[ "$(git rev-parse --is-inside-work-tree)" != "true" ]]; then
        return 1
    fi

    USER_NAME=$(get_config "su.${SU_NAME}.name")
    if (( $? != 0 )); then
        echo -e "su.${SU_NAME}.name not defined" 1>&2
        return 1
    fi
    USER_EMAIL=$(get_config "su.${SU_NAME}.email")
    if (( $? != 0 )); then
        echo -e "su.${SU_NAME}.email not defined" 1>&2
        return 1
    fi
    CORE_SSH_COMMAND=$(get_config "su.${SU_NAME}.sshCommand")
    if (( $? != 0 )); then
        CORE_SSH_COMMAND=
    fi

    git config user.name "$USER_NAME"
    git config user.email "$USER_EMAIL"
    if [[ -n "$CORE_SSH_COMMAND" ]]; then
        vercomp "$GIT_VERSION" 2.3
        if (( $? == 2 )); then
            echo "core.sshCommand not supported (Git v${GIT_VERSION} < v2.3)" 1>&2
        fi
        git config core.sshCommand "$CORE_SSH_COMMAND"
    else
        git config --unset core.sshCommand
    fi
}

su_git()
{
    if [[ "$2" == "init" ]] || [[ "$2" == "clone" ]]; then
        su_git_outrepo_cmd "$@"
    else
        su_git_inrepo_cmd "$@"
    fi
}

su_git_outrepo_cmd() {
    local SU_NAME=$1
    shift

    vercomp "$GIT_VERSION" 2.3
    if (( $? == 2 )); then
        echo "core.sshCommand not supported (Git v${GIT_VERSION} < v2.3)" 1>&2
    fi

    CORE_SSH_COMMAND=$(get_config "su.${SU_NAME}.sshCommand")
    if (( $? != 0 )); then
        CORE_SSH_COMMAND=
    fi

    GIT_SSH_COMMAND="$CORE_SSH_COMMAND" git "$@" && (cd "$(extract_repo_dir "$@")" && apply_su "$SU_NAME")
}

su_git_inrepo_cmd() {
    local SU_NAME=$1
    shift

    apply_su "$SU_NAME" && git "$@"
}

if [[ $# == 1 ]]; then
    if [[ "$1" == "-l" ]] || [[ "$1" == "--list" ]]; then
        print_su_list
    else
        apply_su "$SU_NAME"
    fi
else
    su_git "$@"
fi