#
# Copyright (c) 2022-2023, Jesús Daniel Colmenares Oviedo <DtxdF@disroot.org>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# * Redistributions of source code must retain the above copyright notice, this
#   list of conditions and the following disclaimer.
#
# * Redistributions in binary form must reproduce the above copyright notice,
#   this list of conditions and the following disclaimer in the documentation
#   and/or other materials provided with the distribution.
#
# * Neither the name of the copyright holder nor the names of its
#   contributors may be used to endorse or promote products derived from
#   this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

lib_loaded_var()
{
	local var="$1"
	local val

	if [ -z "${var}" ]; then
		echo "usage: lib_loaded_var var" >&2
		exit 64 # EX_USAGE
	fi

	val=`eval echo "\\$${var}"`
	printf "%s\n" "${val}"
}

lib_load()
{
	local library library_bs
	local loaded

	library="$1"

	# Since the log library has not yet been loaded, this is necessary.
	if [ -z "${library}" ]; then
		echo "usage: lib_load library" >&2
		exit 64 # EX_USAGE
	fi

	# mksum is better, but slower.
	library_bs=`echo "${library}" | sed -E 's/[^a-zA-Z0-9_]+//g'`
	if [ -z "${library_bs}" ]; then
		echo "Invalid name \"${library_bs}\"." >&2
		exit 65 # EX_DATAERR
	fi

	loaded=`eval echo \\$__lib_${library_bs}_loaded__`

	if [ -z "${loaded}" ]; then
		setvar __lib_${library_bs}_loaded__ 1

		. "${library}"
	fi
}
