#!/bin/sh
#
# git-submodules.sh: add, init, update or list git submodules
#
# Copyright (c) 2007 Lars Hjemli

USAGE='[--quiet] [--cached] [add <repo> [-b branch]|status|init|update] [--] [<path>...]'
. git-sh-setup
require_work_tree

add=
branch=
init=
update=
status=
quiet=
cached=

#
# print stuff on stdout unless -q was specified
#
say()
{
        if test -z "$quiet"
        then
                echo "$@"
        fi
}

# NEEDSWORK: identical function exists in get_repo_base in clone.sh
get_repo_base() {
        (
                cd "`/bin/pwd`" &&
                cd "$1" || cd "$1.git" &&
                {
                        cd .git
                        pwd
                }
        ) 2>/dev/null
}

# Resolve relative url by appending to parent's url
resolve_relative_url ()
{
        branch="$(git symbolic-ref HEAD 2>/dev/null)"
        remote="$(git config branch.${branch#refs/heads/}.remote)"
        remote="${remote:-origin}"
        remoteurl="$(git config remote.$remote.url)" ||
                die "remote ($remote) does not have a url in .git/config"
        url="$1"
        while test -n "$url"
        do
                case "$url" in
                ../*)
                        url="${url#../}"
                        remoteurl="${remoteurl%/*}"
                        ;;
                ./*)
                        url="${url#./}"
                        ;;
                *)
                        break;;
                esac
        done
        echo "$remoteurl/$url"
}

#
# Map submodule path to submodule name
#
# $1 = path
#
module_name()
{
        # Do we have "submodule.<something>.path = $1" defined in .gitmodules file?
        re=$(printf '%s' "$1" | sed -e 's/\([^a-zA-Z0-9_]\)/\\\1/g')
        name=$( GIT_CONFIG=.gitmodules \
                git config --get-regexp '^submodule\..*\.path$' |
                sed -n -e 's|^submodule\.\(.*\)\.path '"$re"'$|\1|p' )
       test -z "$name" &&
       die "No submodule mapping found in .gitmodules for path '$path'"
       echo "$name"
}

#
# Clone a submodule
#
# Prior to calling, modules_update checks that a possibly existing
# path is not a git repository.
# Likewise, module_add checks that path does not exist at all,
# since it is the location of a new submodule.
#
module_clone()
{
        path=$1
        url=$2

        # If there already is a directory at the submodule path,
        # expect it to be empty (since that is the default checkout
        # action) and try to remove it.
        # Note: if $path is a symlink to a directory the test will
        # succeed but the rmdir will fail. We might want to fix this.
        if test -d "$path"
        then
                rmdir "$path" 2>/dev/null ||
                die "Directory '$path' exist, but is neither empty nor a git repository"
        fi

        test -e "$path" &&
        die "A file already exist at path '$path'"

        git-clone -n "$url" "$path" ||
        die "Clone of '$url' into submodule path '$path' failed"
}

#
# Add a new submodule to the working tree, .gitmodules and the index
#
# $@ = repo [path]
#
# optional branch is stored in global branch variable
#
module_add()
{
        repo=$1
        path=$2

        if test -z "$repo"; then
                usage
        fi

        case "$repo" in
        ./*|../*)
                # dereference source url relative to parent's url
                realrepo="$(resolve_relative_url $repo)" ;;
        *)
                # Turn the source into an absolute path if
                # it is local
                if base=$(get_repo_base "$repo"); then
                        repo="$base"
                        realrepo=$repo
                fi
                ;;
        esac

        # Guess path from repo if not specified or strip trailing slashes
        if test -z "$path"; then
                path=$(echo "$repo" | sed -e 's|/*$||' -e 's|:*/*\.git$||' -e 's|.*[/:]||g')
        else
                path=$(echo "$path" | sed -e 's|/*$||')
        fi

        test -e "$path" &&
        die "'$path' already exists"

        git ls-files --error-unmatch "$path" > /dev/null 2>&1 &&
        die "'$path' already exists in the index"

        module_clone "$path" "$realrepo" || exit
        (unset GIT_DIR && cd "$path" && git checkout -q ${branch:+-b "$branch" "origin/$branch"}) ||
        die "Unable to checkout submodule '$path'"
        git add "$path" ||
        die "Failed to add submodule '$path'"

        GIT_CONFIG=.gitmodules git config submodule."$path".path "$path" &&
        GIT_CONFIG=.gitmodules git config submodule."$path".url "$repo" &&
        git add .gitmodules ||
        die "Failed to register submodule '$path'"
}

#
# Register submodules in .git/config
#
# $@ = requested paths (default to all)
#
modules_init()
{
        git ls-files --stage -- "$@" | grep -e '^160000 ' |
        while read mode sha1 stage path
        do
                # Skip already registered paths
                name=$(module_name "$path") || exit
                url=$(git config submodule."$name".url)
                test -z "$url" || continue

                url=$(GIT_CONFIG=.gitmodules git config submodule."$name".url)
                test -z "$url" &&
                die "No url found for submodule path '$path' in .gitmodules"

                # Possibly a url relative to parent
                case "$url" in
                ./*|../*)
                        url="$(resolve_relative_url "$url")"
                        ;;
                esac

                git config submodule."$name".url "$url" ||
                die "Failed to register url for submodule path '$path'"

                say "Submodule '$name' ($url) registered for path '$path'"
        done
}

#
# Update each submodule path to correct revision, using clone and checkout as needed
#
# $@ = requested paths (default to all)
#
modules_update()
{
        git ls-files --stage -- "$@" | grep -e '^160000 ' |
        while read mode sha1 stage path
        do
                name=$(module_name "$path") || exit
                url=$(git config submodule."$name".url)
                if test -z "$url"
                then
                        # Only mention uninitialized submodules when its
                        # path have been specified
                        test "$#" != "0" &&
                        say "Submodule path '$path' not initialized"
                        continue
                fi

                if ! test -d "$path"/.git
                then
                        module_clone "$path" "$url" || exit
                        subsha1=
                else
                        subsha1=$(unset GIT_DIR && cd "$path" &&
                                git rev-parse --verify HEAD) ||
                        die "Unable to find current revision in submodule path '$path'"
                fi

                if test "$subsha1" != "$sha1"
                then
                        (unset GIT_DIR && cd "$path" && git-fetch &&
                                git-checkout -q "$sha1") ||
                        die "Unable to checkout '$sha1' in submodule path '$path'"

                        say "Submodule path '$path': checked out '$sha1'"
                fi
        done
}

set_name_rev () {
        revname=$( (
                unset GIT_DIR &&
                cd "$1" && {
                        git describe "$2" 2>/dev/null ||
                        git describe --tags "$2" 2>/dev/null ||
                        git describe --contains --tags "$2"
                }
        ) )
        test -z "$revname" || revname=" ($revname)"
}

#
# List all submodules, prefixed with:
#  - submodule not initialized
#  + different revision checked out
#
# If --cached was specified the revision in the index will be printed
# instead of the currently checked out revision.
#
# $@ = requested paths (default to all)
#
modules_list()
{
        git ls-files --stage -- "$@" | grep -e '^160000 ' |
        while read mode sha1 stage path
        do
                name=$(module_name "$path") || exit
                url=$(git config submodule."$name".url)
                if test -z "url" || ! test -d "$path"/.git
                then
                        say "-$sha1 $path"
                        continue;
                fi
                set_name_rev "$path" "$sha1"
                if git diff-files --quiet -- "$path"
                then
                        say " $sha1 $path$revname"
                else
                        if test -z "$cached"
                        then
                                sha1=$(unset GIT_DIR && cd "$path" && git rev-parse --verify HEAD)
                                set_name_rev "$path" "$sha1"
                        fi
                        say "+$sha1 $path$revname"
                fi
        done
}

while test $# != 0
do
        case "$1" in
        add)
                add=1
                ;;
        init)
                init=1
                ;;
        update)
                update=1
                ;;
        status)
                status=1
                ;;
        -q|--quiet)
                quiet=1
                ;;
        -b|--branch)
                case "$2" in
                '')
                        usage
                        ;;
                esac
                branch="$2"; shift
                ;;
        --cached)
                cached=1
                ;;
        --)
                break
                ;;
        -*)
                usage
                ;;
        *)
                break
                ;;
        esac
        shift
done

case "$add,$branch" in
1,*)
        ;;
,)
        ;;
,*)
        usage
        ;;
esac

case "$add,$init,$update,$status,$cached" in
1,,,,)
        module_add "$@"
        ;;
,1,,,)
        modules_init "$@"
        ;;
,,1,,)
        modules_update "$@"
        ;;
,,,*,*)
        modules_list "$@"
        ;;
*)
        usage
        ;;
esac