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# -*-eselect-*-  vim: ft=eselect

# Copyright (c) 2005-2013 Gentoo Foundation

#

# This file is part of the 'eselect' tools framework.

#

# eselect is free software: you can redistribute it and/or modify it under the

# terms of the GNU General Public License as published by the Free Software

# Foundation, either version 2 of the License, or (at your option) any later

# version.

#

# eselect is distributed in the hope that it will be useful, but WITHOUT ANY

# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR

# A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License along with

# eselect.  If not, see <http://www.gnu.org/licenses/>.

# This library is for managing a common binary symlink like /bin/sh

# or /usr/bin/pinentry. To use it, you need to set the following

# variables:

#

# SYMLINK_PATH is the name of symlink being created, e.g. "/bin/sh".

# The path should be absolute, without EPREFIX (it will be added).

#

# SYMLINK_TARGETS is the list (bash array) of targets being available.

# The paths should be relative to ${SYMLINK_PATH}. Only basenames

# of the targets will be displayed to user. Best (preferred) targets

# should go earlier on the list.

#

# SYMLINK_DESCRIPTION is the human-friendly name of the symlink, e.g.

# "POSIX shell". It will be used in the context of "implementation"

# or "symlink". Defaults to basename of ${SYMLINK_PATH}.

#

# SYMLINK_CRUCIAL should be set to a non-null value if existence of no

# targets should trigger a fatal error rather than silent symlink

# removal.

# Maintainer: mgorny@gentoo.org

# Based on the work of:

# - Erik Hahn; bug #214817

# - Samuli Suominen <ssuominen@gentoo.org>; eselect-pinentry

## Global variables ##

if [[ ! ${SYMLINK_PATH} ]]; then

	die "SYMLINK_PATH needs to be set by eselect module."

fi

if [[ ! ${SYMLINK_TARGETS[@]} ]]; then

	die "SYMLINK_TARGETS need to be set by eselect module."

fi

: ${SYMLINK_DESCRIPTION:-${SYMLINK_PATH##*/}}

## Functions ##

# find a list of symlink targets, best first

find_targets() {

	local basedir=${SYMLINK_PATH%/*}

	TARGETS=()

	local t

	for t in "${SYMLINK_TARGETS[@]}"; do

		if [[ -x ${EROOT}${basedir}/${t} ]]; then

			TARGETS+=( ${t} )

		fi

	done

}

# set the pinentry symlink

set_symlinks() {

	local target="${1}" targets

	local basedir=${SYMLINK_PATH%/*}

	[[ ! -L ${EROOT}${SYMLINK_PATH} && -e ${EROOT}${SYMLINK_PATH} ]] && \

		die -q "${EROOT}${SYMLINK_PATH} is not a symlink!"

	if is_number "${target}" && [[ ${target} -ge 1 ]]; then

		local TARGETS

		find_targets

		target=${TARGETS[target-1]}

	elif [[ ! -x ${EROOT}${basedir}/${target} ]]; then

		# try basename matching

		local TARGETS t

		find_targets

		for t in "${TARGETS[@]}"; do

			if [[ ${t##*/} == ${target} ]]; then

				target=${t}

				break

			fi

		done

	fi

	if [[ -x ${EROOT}${basedir}/${target} ]]; then

		local tmpf=${EROOT}${SYMLINK_PATH}.new

		# we could use 'ln -f' to directly replace the symlink

		# but 'mv' is an atomic operation so it should be more fault-proof

		ln -s "${target}" "${tmpf}" || \

			die -q "Unable to create temporary symlink"

		if ! mv "${tmpf}" "${EROOT}${SYMLINK_PATH}"; then

			rm -f "${tmpf}" # cleanup

			die -q "Unable to replace ${EROOT}${SYMLINK_PATH} symlink with ${target}"

		fi

	else

		die -q "Target '${target}' doesn't appear to be valid!"

	fi

}

### show action ###

describe_show() {

	echo "Show the current ${SYMLINK_DESCRIPTION} implementation"

}

do_show() {

	[[ ${@} ]] && die -q "Too many parameters"

	write_list_start "Current ${SYMLINK_DESCRIPTION} implementation:"

	if [[ -L ${EROOT}${SYMLINK_PATH} ]]; then

		local t=$(readlink "${EROOT}${SYMLINK_PATH}")

		write_kv_list_entry "${t##*/}" ""

	elif [[ -e ${EROOT}${SYMLINK_PATH} ]]; then

		write_kv_list_entry "(not a symlink)" ""

	else

		write_kv_list_entry "(unset)" ""

	fi

}

### list action ###

describe_list() {

	echo "List available ${SYMLINK_DESCRIPTION} implementations"

}

do_list() {

	[[ ${@} ]] && die -q "Too many parameters"

	local i TARGETS

	find_targets

	write_list_start "Available ${SYMLINK_DESCRIPTION} implementations:"

	if [[ ${TARGETS[@]} ]]; then

		local curr=$(readlink "${EROOT}${SYMLINK_PATH}")

		for (( i = 0; i < ${#TARGETS[@]}; i++ )) ; do

			[[ ${TARGETS[${i}]##*/} == ${curr##*/} ]] && \

				TARGETS[${i}]+=" $(highlight '*')"

		done

		write_numbered_list "${TARGETS[@]##*/}"

	else

		write_kv_list_entry "(none found)" ""

	fi

}

### set action ###

describe_set() {

	echo "Set a new ${SYMLINK_DESCRIPTION} implementation"

}

describe_set_options() {

	echo "target : Target name, number (from 'list' action) or path"

}

describe_set_parameters() {

	echo "<target>"

}

do_set() {

	if [[ ${#} != 1 ]]; then

		die -q "set takes exactly one parameter"

	else

		set_symlinks "${1}"

	fi

}

### update action ###

describe_update() {

	echo "Automatically update the ${SYMLINK_DESCRIPTION} implementation"

}

describe_update_options() {

	echo "--if-unset : do not override existing implementation"

}

do_update() {

	[[ ${1} == ifunset ]] && set -- --if-unset "${@:2}"

	if [[ ( ${1} && ${1} != '--if-unset' ) || ${2} ]]

	then

		die -q "usage error"

	fi

	if [[ ${1} == '--if-unset' && -L ${EROOT}${SYMLINK_PATH} \

			&& -x ${EROOT}${SYMLINK_PATH} ]]

	then

		return

	fi

	local TARGETS

	find_targets

	if [[ ! ${TARGETS[@]} ]]; then

		if [[ ${SYMLINK_CRUCIAL} ]]; then

			die "No targets for ${EROOT}${SYMLINK_PATH}, system likely broken."

		else

			rm -f "${EROOT}${SYMLINK_PATH}"

		fi

	fi

	set_symlinks "${TARGETS[0]}"

}

# vim:ts=4:sts=4:sw=4