vcsh

#!/bin/sh

# This program is licensed under the GNU GPL version 2 or later.
# (c) Richard "RichiH" Hartmann <richih@debian.org>, 2011-2015
# For details, see LICENSE. To submit patches, you have to agree to
# license your code under the GNU GPL version 2 or later.

# While the following is not legally binding, the author would like to
# explain the choice of GPLv2+ over GPLv3+.
# The author prefers GPLv3+ over GPLv2+ but feels it's better to maintain
# full compatibility's with Git. In case Git ever changes its licensing terms,
# which is admittedly extremely unlikely to the point of being impossible,
# this software will most likely follow suit.

# This should always be the first line of code to facilitate debugging
[ -n "$VCSH_DEBUG" ] && set -vx


# If '.git-HEAD' is appended to the version, you are seeing an unreleased
# version of vcsh; the master branch is supposed to be clean at all times
# so you can most likely just use it nonetheless
VERSION='1.20141026'
SELF=$(basename $0)

fatal() {
	echo "$SELF: fatal: $1" >&2
	[ -z $2 ] && exit 1
	exit $2
}

# We need to run getops as soon as possible so we catch -d and other
# options that will modify our behaviour.
# Commands are handled at the end of this script.
while getopts "c:dv" flag; do
	if [ x"$1" = x'-d' ] || [ x"$1" = x'--debug' ]; then
		set -vx
		VCSH_DEBUG=1
		echo "debug mode on"
		echo "$SELF $VERSION"
	elif [ x"$1" = x'-v' ]; then
		VCSH_VERBOSE=1
		echo "verbose mode on"
		echo "$SELF $VERSION"
	elif [ x"$1" = x'-c' ]; then
		VCSH_OPTION_CONFIG=$OPTARG
	fi
	shift 1
done

source_all() {
	# Source file even if it's in $PWD and does not have any slashes in it
	case $1 in
		*/*) . "$1";;
		*)   . "$PWD/$1";;
	esac;
}


# Read configuration and set defaults if anything's not set
[ -n "$VCSH_DEBUG" ]                  && set -vx
: ${XDG_CONFIG_HOME:="$HOME/.config"}

# Read configuration files if there are any
[ -r "/etc/vcsh/config" ]             && . "/etc/vcsh/config"
[ -r "$XDG_CONFIG_HOME/vcsh/config" ] && . "$XDG_CONFIG_HOME/vcsh/config"
if [ -n "$VCSH_OPTION_CONFIG" ]; then
	# Source $VCSH_OPTION_CONFIG if it can be read and is in $PWD of $PATH
	if [ -r "$VCSH_OPTION_CONFIG" ]; then
		source_all "$VCSH_OPTION_CONFIG"
	else
		fatal "Can not read configuration file '$VCSH_OPTION_CONFIG'" 1
	fi
fi
[ -n "$VCSH_DEBUG" ]                  && set -vx

# Read defaults
: ${VCSH_REPO_D:="$XDG_CONFIG_HOME/vcsh/repo.d"}
: ${VCSH_HOOK_D:="$XDG_CONFIG_HOME/vcsh/hooks-enabled"}
: ${VCSH_OVERLAY_D:="$XDG_CONFIG_HOME/vcsh/overlays-enabled"}
: ${VCSH_BASE:="$HOME"}
: ${VCSH_GITIGNORE:=exact}
: ${VCSH_GITATTRIBUTES:=none}
: ${VCSH_WORKTREE:=absolute}

if [ ! "x$VCSH_GITIGNORE" = 'xexact' ] && [ ! "x$VCSH_GITIGNORE" = 'xnone' ] && [ ! "x$VCSH_GITIGNORE" = 'xrecursive' ]; then
	fatal "'\$VCSH_GITIGNORE' must equal 'exact', 'none', or 'recursive'" 1
fi

if [ ! "x$VCSH_WORKTREE" = 'xabsolute' ] && [ ! "x$VCSH_WORKTREE" = 'xrelative' ]; then
	fatal "'\$VCSH_WORKTREE' must equal 'absolute', or 'relative'" 1
fi


help() {
	echo "usage: $SELF <options> <command>

   options:
   -c <file>            Source file
   -d                   Enable debug mode
   -v                   Enable verbose mode

   commands:
   clone [-b <branch>] \\
         <remote> \\
         [<repo>]       Clone from an existing repository
   commit               Commit in all repositories
   delete <repo>        Delete an existing repository
   enter <repo>         Enter repository; spawn new instance of \$SHELL
   help                 Display this help text
   init <repo>          Initialize a new repository
   list                 List all repositories
   list-tracked \\
        [<repo>]        List all files tracked all or one repositories
   list-untracked \\
        [<-r>] [<repo>] List all files not tracked by all or one repositories
   pull                 Pull from all vcsh remotes
   push                 Push to vcsh remotes
   rename <repo> \\
          <newname>     Rename repository
   run <repo> \\
       <command>        Use this repository
   status \\
     [--terse] [<repo>] Show statuses of all/one vcsh repositories
   upgrade <repo>       Upgrade repository to currently recommended settings
   version              Print version information
   which <substring>    Find substring in name of any tracked file
   write-gitignore \\
   <repo>               Write .gitignore.d/<repo> via git ls-files

   <repo> <git command> Shortcut to run git commands directly
   <repo>               Shortcut to enter repository" >&2
}

debug() {
	[ -n "$VCSH_DEBUG" ] && echo "$SELF: debug: $@"
}

verbose() {
	if [ -n "$VCSH_DEBUG" ] || [ -n "$VCSH_VERBOSE" ]; then echo "$SELF: verbose: $@"; fi
}

error() {
	echo "$SELF: error: $1" >&2
}

info() {
	echo "$SELF: info: $1"
}

clone() {
	hook pre-clone
	init
	git remote add origin "$GIT_REMOTE"
	git checkout -b "$VCSH_BRANCH" || return $?
	git config branch."$VCSH_BRANCH".remote origin
	git config branch."$VCSH_BRANCH".merge  refs/heads/"$VCSH_BRANCH"
	if [ $(git ls-remote origin "$VCSH_BRANCH" 2> /dev/null | wc -l ) -lt 1 ]; then
		info "remote is empty, not merging anything.
  You should add files to your new repository."
		exit
	fi
	git fetch origin "$VCSH_BRANCH"
	hook pre-merge
	git ls-tree -r --name-only origin/"$VCSH_BRANCH" | (while read object; do
		[ -e "$object" ] &&
			error "'$object' exists." &&
			VCSH_CONFLICT=1
	done
	[ x"$VCSH_CONFLICT" = x'1' ]) &&
		fatal "will stop after fetching and not try to merge!
  Once this situation has been resolved, run 'vcsh $VCSH_REPO_NAME pull' to finish cloning." 17
	git merge origin/"$VCSH_BRANCH"
	hook post-merge
	hook post-clone
	retire
	hook post-clone-retired
}

commit() {
	hook pre-commit
	for VCSH_REPO_NAME in $(list); do
		echo "$VCSH_REPO_NAME: "
		GIT_DIR=$VCSH_REPO_D/$VCSH_REPO_NAME.git; export GIT_DIR
		use
		git commit --untracked-files=no --quiet
		VCSH_COMMAND_RETURN_CODE=$?
		echo
	done
	hook post-commit
}

delete() {
	cd "$VCSH_BASE" || fatal "could not enter '$VCSH_BASE'" 11
	use
	info "This operation WILL DESTROY DATA!"
	files=$(git ls-files)
	echo "These files will be deleted:

$files

AGAIN, THIS WILL DELETE YOUR DATA!
To continue, type 'Yes, do as I say'"
	read answer
	[ "x$answer" = 'xYes, do as I say' ] || exit 16
	for file in $files; do
		rm -f $file || info "could not delete '$file', continuing with deletion"
	done
	rm -rf "$GIT_DIR" || error "could not delete '$GIT_DIR'"
}

enter() {
	hook pre-enter
	use
	$SHELL
	hook post-enter
}

git_dir_exists() {
	[ -d "$GIT_DIR" ] || fatal "no repository found for '$VCSH_REPO_NAME'" 12
}

hook() {
	for hook in "$VCSH_HOOK_D/$1"* "$VCSH_HOOK_D/$VCSH_REPO_NAME.$1"*; do
		[ -x "$hook" ] || continue
		verbose "executing '$hook'"
		"$hook"
	done
}

init() {
	hook pre-init
	[ ! -e "$GIT_DIR" ] || fatal "'$GIT_DIR' exists" 10
	mkdir -p "$VCSH_BASE" || fatal "could not create '$VCSH_BASE'" 50
	cd "$VCSH_BASE" || fatal "could not enter '$VCSH_BASE'" 11
	git init --shared=0600
	upgrade
	hook post-init
}

list() {
	for repo in "$VCSH_REPO_D"/*.git; do
		[ -d "$repo" ] && [ -r "$repo" ] && echo "$(basename "$repo" .git)"
	done
}

get_files() {
	GIT_DIR=$VCSH_REPO_D/$VCSH_REPO_NAME.git; export GIT_DIR
	git ls-files
}

list_tracked() {
	VCSH_REPO_NAME=$2; export VCSH_REPO_NAME
	if [ -n "$VCSH_REPO_NAME" ]; then
		get_files | list_tracked_helper
	else
		for VCSH_REPO_NAME in $(list); do
			get_files
		done | list_tracked_helper
	fi
}

list_tracked_helper() {
	sed "s,^,$(printf '%s\n' "$VCSH_BASE/" | sed 's/[,\&]/\\&/g')," | sort -u
}

list_tracked_by() {
	list_tracked $2
}

list_untracked() {
	command -v 'comm' >/dev/null 2>&1 || fatal "Could not find 'comm'"

	temp_file_others=$(mktemp "${TMPDIR:-/tmp}/tmp.XXXXXXXXXX") || fatal 'Could not create temp file'
	temp_file_untracked=$(mktemp "${TMPDIR:-/tmp}/tmp.XXXXXXXXXX") || fatal 'Could not create temp file'
	temp_file_untracked_copy=$(mktemp "${TMPDIR:-/tmp}/tmp.XXXXXXXXXX") || fatal 'Could not create temp file'

	# Hack in support for `vcsh list-untracked -r`...
	directory_opt="--directory"
	shift 1
	while getopts "r" flag; do
		if [ x"$1" = x'-r' ]; then
			unset directory_opt
		fi
		shift 1
	done
	# ...and parse for a potential parameter afterwards. As we shifted things out of $* in during getops, we need to look at $1
	VCSH_REPO_NAME=$1; export VCSH_REPO_NAME

	if [ -n "$VCSH_REPO_NAME" ]; then
		list_untracked_helper $VCSH_REPO_NAME
	else
		for VCSH_REPO_NAME in $(list); do
			list_untracked_helper $VCSH_REPO_NAME
		done
	fi
	cat $temp_file_untracked

	unset directory_opt directory_component
	rm -f $temp_file_others $temp_file_untracked $temp_file_untracked_copy || fatal 'Could not delete temp files'
}

list_untracked_helper() {
	export GIT_DIR="$VCSH_REPO_D/$VCSH_REPO_NAME.git"
	git ls-files --others "$directory_opt" | (
		while read line; do
			echo "$line"
			directory_component=${line%%/*}
			[ -d "$directory_component" ] && printf '%s/\n' "$directory_component"
		done
		) | sort -u > $temp_file_others
	if [ -z "$ran_once" ]; then
		ran_once=1
		cp $temp_file_others $temp_file_untracked || fatal 'Could not copy temp file'
	fi
	cp $temp_file_untracked $temp_file_untracked_copy || fatal 'Could not copy temp file'
	comm -12 $temp_file_others $temp_file_untracked_copy > $temp_file_untracked
}

pull() {
	hook pre-pull
	for VCSH_REPO_NAME in $(list); do
		printf '%s: ' "$VCSH_REPO_NAME"
		GIT_DIR=$VCSH_REPO_D/$VCSH_REPO_NAME.git; export GIT_DIR
		use
		git pull
		VCSH_COMMAND_RETURN_CODE=$?
		echo
	done
	hook post-pull
}

push() {
	hook pre-push
	for VCSH_REPO_NAME in $(list); do
		printf '%s: ' "$VCSH_REPO_NAME"
		GIT_DIR=$VCSH_REPO_D/$VCSH_REPO_NAME.git; export GIT_DIR
		use
		git push
		VCSH_COMMAND_RETURN_CODE=$?
		echo
	done
	hook post-push
}

retire() {
	unset VCSH_DIRECTORY
}

rename() {
	git_dir_exists

	# Verify that new files and directories are non-existant
	[ -d "$GIT_DIR_NEW" ] && fatal "'$GIT_DIR_NEW' exists" 54
	[ -e "$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME_NEW" ] \
		&& fatal "'$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME_NEW' already exists"
	[ -e "$VCSH_BASE/.gitattributes.d/$VCSH_REPO_NAME_NEW" ] \
		&& fatal "'$VCSH_BASE/.gitattributes.d/$VCSH_REPO_NAME_NEW' already exists"

	# Actually move things over
	mv -f "$GIT_DIR" "$GIT_DIR_NEW" || fatal "Could not mv '$GIT_DIR' '$GIT_DIR_NEW'" 52
	if [ -e "$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME" ]; then
		mv -f "$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME" "$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME_NEW" \
		|| fatal "Could not mv '$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME' '$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME_NEW'"
		write_gitignore
	fi
	if [ -e "$VCSH_BASE/.gitattributes.d/$VCSH_REPO_NAME" ]; then
		mv -f "$VCSH_BASE/.gitattributes.d/$VCSH_REPO_NAME" "$VCSH_BASE/.gitattributes.d/$VCSH_REPO_NAME_NEW" \
		|| fatal "Could not mv '$VCSH_BASE/.gitattributes.d/$VCSH_REPO_NAME' '$VCSH_BASE/.gitattributes.d/$VCSH_REPO_NAME_NEW'"
	fi

	# Now that the repository has been renamed, we need to fix up its configuration
	# Overwrite old name..
	GIT_DIR=$GIT_DIR_NEW
	VCSH_REPO_NAME=$VCSH_REPO_NAME_NEW
	# ..and clobber all old configuration
	upgrade
}

run() {
	hook pre-run
	use
	"$@"
	VCSH_COMMAND_RETURN_CODE=$?
	hook post-run
}

status() {
	if [ -t 1 ]; then
		COLORING="-c color.status=always"
	fi
	if [ -n "$VCSH_REPO_NAME" ]; then
		status_helper $VCSH_REPO_NAME
	else
		for VCSH_REPO_NAME in $(list); do
			STATUS=$(status_helper $VCSH_REPO_NAME "$COLORING")
			[ -n "$STATUS" -o -z "$VCSH_STATUS_TERSE" ] && echo "$VCSH_REPO_NAME:"
			[ -n "$STATUS" ]            && echo "$STATUS"
			[ -z "$VCSH_STATUS_TERSE" ] && echo
		done
	fi
}

status_helper() {
	GIT_DIR=$VCSH_REPO_D/$1.git; export GIT_DIR
	VCSH_GIT_OPTIONS=$2
	use
	remote_tracking_branch=$(git rev-parse --abbrev-ref --symbolic-full-name @{u} 2> /dev/null) && {
		commits_behind=$(git log ..${remote_tracking_branch} --oneline | wc -l)
		commits_ahead=$(git log ${remote_tracking_branch}.. --oneline | wc -l)
		[ ${commits_behind} -ne 0 ] && echo "Behind $remote_tracking_branch by $commits_behind commits"
		[ ${commits_ahead} -ne 0 ] && echo "Ahead of $remote_tracking_branch by $commits_ahead commits"
	}
	git ${VCSH_GIT_OPTIONS} status --short --untracked-files='no'
	VCSH_COMMAND_RETURN_CODE=$?
}

upgrade() {
	hook pre-upgrade
	# fake-bare repositories are not bare, actually. Set this to false
	# because otherwise Git complains "fatal: core.bare and core.worktree
	# do not make sense"
	git config core.bare false
	# core.worktree may be absolute or relative to $GIT_DIR, depending on
	# user preference
	if [ ! "x$VCSH_WORKTREE" = 'xabsolute' ]; then
		git config core.worktree "$(cd "$GIT_DIR" && GIT_WORK_TREE=$VCSH_BASE git rev-parse --show-cdup)"
	elif [ ! "x$VCSH_WORKTREE" = 'xrelative' ]; then
		git config core.worktree "$VCSH_BASE"
	fi
	[ ! "x$VCSH_GITIGNORE" = 'xnone' ] && git config core.excludesfile ".gitignore.d/$VCSH_REPO_NAME"
	[ ! "x$VCSH_GITATTRIBUTES" = 'xnone' ] && git config core.attributesfile ".gitattributes.d/$VCSH_REPO_NAME"
	git config vcsh.vcsh 'true'
	use
	[ -e "$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME" ] && git add -f "$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME"
	[ -e "$VCSH_BASE/.gitattributes.d/$VCSH_REPO_NAME" ] && git add -f "$VCSH_BASE/.gitattributes.d/$VCSH_REPO_NAME"
	hook post-upgrade
}

use() {
	git_dir_exists
	VCSH_DIRECTORY=$VCSH_REPO_NAME; export VCSH_DIRECTORY
}

which() {
	[ -e "$VCSH_COMMAND_PARAMETER" ] || fatal "'$VCSH_COMMAND_PARAMETER' does not exist" 1
	for VCSH_REPO_NAME in $(list); do
		for VCSH_FILE in $(get_files); do
			echo "$VCSH_FILE" | grep -q "$VCSH_COMMAND_PARAMETER" && echo "$VCSH_REPO_NAME: $VCSH_FILE"
		done
	done | sort -u
}

write_gitignore() {
	# Don't do anything if the user does not want to write gitignore
	if [ "x$VCSH_GITIGNORE" = 'xnone' ]; then
		info "Not writing gitignore as '\$VCSH_GITIGNORE' is set to 'none'"
		exit
	fi

	use
	cd "$VCSH_BASE" || fatal "could not enter '$VCSH_BASE'" 11
	OLDIFS=$IFS
	IFS=$(printf '\n\t')
	gitignores=$(for file in $(git ls-files); do
		while true; do
			echo "$file"; new=${file%/*}
			[ x"$file" = x"$new" ] && break
			file=$new
		done;
	done | sort -u)

	# Contrary to GNU mktemp, mktemp on BSD/OSX requires a template for temp files
	# Using a template makes GNU mktemp default to $PWD and not #TMPDIR for tempfile location
	# To make every OS happy, set full path explicitly
	tempfile=$(mktemp "${TMPDIR:-/tmp}/tmp.XXXXXXXXXX") || fatal "could not create tempfile: '${tempfile}'" 51

	echo '*' > "$tempfile" || fatal "could not write to '$tempfile'" 57
	for gitignore in $gitignores; do
		echo "$gitignore" | sed 's@^@!/@' >> "$tempfile" || fatal "could not write to '$tempfile'" 57
		if [ "x$VCSH_GITIGNORE" = 'xrecursive' ] && [ -d "$gitignore" ]; then
			{ echo "$gitignore/*" | sed 's@^@!/@' >> "$tempfile" || fatal "could not write to '$tempfile'" 57; }
		fi
	done
	IFS=$OLDIFS
	if diff -N "$tempfile" "$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME" > /dev/null; then
		rm -f "$tempfile" || error "could not delete '$tempfile'"
		exit
	fi
	if [ -e "$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME" ]; then
		info "'$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME' differs from new data, moving it to '$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME.bak'"
		mv -f "$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME" "$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME.bak" ||
			fatal "could not move '$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME' to '$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME.bak'" 53
	fi
	mv -f "$tempfile" "$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME" ||
		fatal "could not move '$tempfile' to '$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME'" 53
}

debug $(git version)

if [ ! "x$VCSH_GITIGNORE" = 'xexact' ] && [ ! "x$VCSH_GITIGNORE" = 'xnone' ] && [ ! "x$VCSH_GITIGNORE" = 'xrecursive' ]; then
	fatal "'\$VCSH_GITIGNORE' must equal 'exact', 'none', or 'recursive'" 1
fi

VCSH_COMMAND=$1; export VCSH_COMMAND

case $VCSH_COMMAND in
	clon|clo|cl) VCSH_COMMAND=clone;;
	commi|comm|com|co) VCSH_COMMAND=commit;;
	delet|dele|del|de) VCSH_COMMAND=delete;;
	ente|ent|en) VCSH_COMMAND=enter;;
	hel|he) VCSH_COMMAND=help;;
	ini|in) VCSH_COMMAND=init;;
	pul) VCSH_COMMAND=pull;;
	pus) VCSH_COMMAND=push;;
	renam|rena|ren|re) VCSH_COMMAND=rename;;
	ru) VCSH_COMMAND=run;;
	statu|stat|sta|st) VCSH_COMMAND=status;;
	upgrad|upgra|upgr|up) VCSH_COMMAND=upgrade;;
	versio|versi|vers|ver|ve) VCSH_COMMAND=version;;
	which|whi|wh) VCSH_COMMAND=which;;
	write|writ|wri|wr) VCSH_COMMAND=write-gitignore;;
esac    

if [ x"$VCSH_COMMAND" = x'clone' ]; then
	VCSH_BRANCH=
	if [ "$2" = -b ]; then
		VCSH_BRANCH=$3
		shift
		shift
	fi
	[ -z "$2" ] && fatal "$VCSH_COMMAND: please specify a remote" 1
	GIT_REMOTE="$2"
	[ -n "$VCSH_BRANCH" ] || if [ "$3" = -b ]; then
		VCSH_BRANCH=$4
		shift
		shift
	fi
	if [ -n "$3" ]; then
		VCSH_REPO_NAME=$3
		[ -z "$VCSH_BRANCH" ] && [ "$4" = -b ] && VCSH_BRANCH=$5
	else
		VCSH_REPO_NAME=$(basename "${GIT_REMOTE#*:}" .git)
	fi
	[ -z "$VCSH_REPO_NAME" ] && fatal "$VCSH_COMMAND: could not determine repository name" 1
	export VCSH_REPO_NAME
	[ -n "$VCSH_BRANCH" ] || VCSH_BRANCH=master
	GIT_DIR=$VCSH_REPO_D/$VCSH_REPO_NAME.git; export GIT_DIR
elif [ "$VCSH_COMMAND" = 'version' ]; then
	echo "$SELF $VERSION"
	git version
	exit
elif [ x"$VCSH_COMMAND" = x'which' ]; then
	[ -z "$2" ] && fatal "$VCSH_COMMAND: please specify a filename" 1
	[ -n "$3" ] && fatal "$VCSH_COMMAND: too many parameters" 1
	VCSH_COMMAND_PARAMETER=$2; export VCSH_COMMAND_PARAMETER
elif [ x"$VCSH_COMMAND" = x'delete' ]           ||
     [ x"$VCSH_COMMAND" = x'enter' ]            ||
     [ x"$VCSH_COMMAND" = x'init' ]             ||
     [ x"$VCSH_COMMAND" = x'list-tracked-by' ]  ||
     [ x"$VCSH_COMMAND" = x'rename' ]           ||
     [ x"$VCSH_COMMAND" = x'run' ]              ||
     [ x"$VCSH_COMMAND" = x'upgrade' ]          ||
     [ x"$VCSH_COMMAND" = x'write-gitignore' ]; then
	[ -z "$2" ]                                     && fatal "$VCSH_COMMAND: please specify repository to work on" 1
	[ x"$VCSH_COMMAND" = x'rename' ] && [ -z "$3" ] && fatal "$VCSH_COMMAND: please specify a target name" 1
	[ x"$VCSH_COMMAND" = x'run'    ] && [ -z "$3" ] && fatal "$VCSH_COMMAND: please specify a command" 1
	VCSH_REPO_NAME=$2; export VCSH_REPO_NAME
	GIT_DIR=$VCSH_REPO_D/$VCSH_REPO_NAME.git; export GIT_DIR
	[ x"$VCSH_COMMAND" = x'rename' ] && { VCSH_REPO_NAME_NEW=$3; export VCSH_REPO_NAME_NEW;
	                                      GIT_DIR_NEW=$VCSH_REPO_D/$VCSH_REPO_NAME_NEW.git; export GIT_DIR_NEW; }
	[ x"$VCSH_COMMAND" = x'run' ]    && shift 2
elif [ x"$VCSH_COMMAND" = x'commit' ] ||
     [ x"$VCSH_COMMAND" = x'list'   ] ||
     [ x"$VCSH_COMMAND" = x'list-tracked' ] ||
     [ x"$VCSH_COMMAND" = x'list-untracked' ] ||
     [ x"$VCSH_COMMAND" = x'pull'   ] ||
     [ x"$VCSH_COMMAND" = x'push'   ]; then
	:
elif [ x"$VCSH_COMMAND" = x'status' ]; then
	if [ x"$2" = x'--terse' ]; then
		VCSH_STATUS_TERSE=1; export VCSH_STATUS_TERSE
		shift
	fi
	VCSH_REPO_NAME=$2; export VCSH_REPO_NAME
elif [ -n "$2" ]; then
	VCSH_COMMAND='run'; export VCSH_COMMAND
	VCSH_REPO_NAME=$1; export VCSH_REPO_NAME
	GIT_DIR=$VCSH_REPO_D/$VCSH_REPO_NAME.git; export GIT_DIR
	[ -d "$GIT_DIR" ] || { help; exit 1; }
	shift 1
	set -- "git" "$@"
elif [ -n "$VCSH_COMMAND" ]; then
	VCSH_COMMAND='enter'; export VCSH_COMMAND
	VCSH_REPO_NAME=$1; export VCSH_REPO_NAME
	GIT_DIR=$VCSH_REPO_D/$VCSH_REPO_NAME.git; export GIT_DIR
	[ -d "$GIT_DIR" ] || { help; exit 1; }
else
	# $1 is empty, or 'help'
	help && exit
fi

# Did we receive a directory instead of a name?
# Mangle the input to fit normal operation.
if echo "$VCSH_REPO_NAME" | grep -q '/'; then
	GIT_DIR=$VCSH_REPO_NAME; export GIT_DIR
	VCSH_REPO_NAME=$(basename "$VCSH_REPO_NAME" .git); export VCSH_REPO_NAME
fi

check_dir() {
	check_directory="$1"
	if [ ! -d "$check_directory" ]; then
		if [ -e "$check_directory" ]; then
			fatal "'$check_directory' exists but is not a directory" 13
		else
			verbose "attempting to create '$check_directory'"
			mkdir -p "$check_directory" || fatal "could not create '$check_directory'" 50
		fi
	fi
}

check_dir "$VCSH_REPO_D"
[ ! "x$VCSH_GITIGNORE" = 'xnone' ] && check_dir "$VCSH_BASE/.gitignore.d"
[ ! "x$VCSH_GITATTRIBUTES" = 'xnone' ] && check_dir "$VCSH_BASE/.gitattributes.d"

verbose "$VCSH_COMMAND begin"
VCSH_COMMAND=$(echo "$VCSH_COMMAND" | sed 's/-/_/g'); export VCSH_COMMAND

# Source repo-specific configuration file
[ -r "$XDG_CONFIG_HOME/vcsh/config.d/$VCSH_REPO_NAME" ] && . "$XDG_CONFIG_HOME/vcsh/config.d/$VCSH_REPO_NAME"

# source overlay functions
for overlay in "$VCSH_OVERLAY_D/$VCSH_COMMAND"* "$VCSH_OVERLAY_D/$VCSH_REPO_NAME.$VCSH_COMMAND"*; do
	[ -r "$overlay" ] || continue
	info "sourcing '$overlay'"
	. "$overlay"
done

hook pre-command
$VCSH_COMMAND "$@"
hook post-command
verbose "$VCSH_COMMAND end, exiting"
exit $VCSH_COMMAND_RETURN_CODE