# Functions for parsing dependency field values
#
# Copyright (C) 2012, 2018 Patrick McDermott
#
# This file is part of opkbuild.
#
# opkbuild 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 3 of the License, or
# (at your option) any later version.
#
# opkbuild 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 opkbuild.  If not, see <http://www.gnu.org/licenses/>.

## @brief Parse a single package dependency string
## @details \fBob_parse_dep\fP() parses package dependencies in the format
##          \fIpkg:archqual (rel ver) [arches] <plats>\fP, where the components
##          \fI:archqual\fP, \fI(rel ver)\fP, \fI[arches]\fP, and \fI<plats>\fP
##          are optional.
## @option -P pkg_var      The name of the variable in which to store the
##                         package name.
## @option -q archqual_var The name of the variable in which to store the
##                         architecture qualifier, if any.
## @option -r rel_var      The name of the variable in which to store the
##                         relationship operator, if any.
## @option -v ver_var      The name of the variable in which to store the
##                         version, if any.
## @option -A arches_var   The name of the variable in which to store the
##                         architecture restrictions, if any.
## @option -l plats_var    The name of the variable in which to store the
##                         platform restrictions, if any.
## @option -a host_arch    The host architecture.  If given, the dependency will
##                         only be printed on standard output if it applies to
##                         the given architecture.
## @option -p host_plat    The host platform.  If given, the dependency will
##                         only be printed on standard output if it applies to
##                         the given platform.
## @operand dep req The dependency to parse.
## @return Returns 0.
## @stdout If \fB-a\fP and \fB\p\fP aren't given, the entire dependency string
##         is printed, with normalized formatting.  If \fB-a\fP and/or \fB-p\fP
##         are given and the dependency applies to their arguments, the
##         dependency string is printed, except for the architecture (if
##         \fB-a\fP given) and/or platform (if \fB-p\fP given) restrictions,
##         with normalized formatting.  Normalized formatting is a string of the
##         format \fIpkg:archqual\ (rel\ ver)\ [arches]\ <plats>\fP.
## @pure maybe This function has side effects when used with any of the options
##             \fB-P\fP, \fB-q\fP, \fB-r\fP, \fB-v\fP, \fB-A\fP, or \fB-l\fP.
ob_parse_dep()
{
	local opt=
	local pkg_var=
	local archqual_var=
	local rel_var=
	local ver_var=
	local arches_var=
	local plats_var=
	local host_arch=
	local host_plat=
	local dep=
	local dep_re=
	local pkg=
	local archqual=
	local rel=
	local ver=
	local arches=
	local plats=
	local comp=
	local comp_var=

	OPTIND=1
	while getopts 'P:q:r:v:A:l:a:p:' opt; do
		case "${opt}" in
			P)
				pkg_var="${OPTARG}"
				if ! _ob_validate_var_name "${pkg_var}"; then
					_ob_abort
				fi
				;;
			q)
				archqual_var="${OPTARG}"
				if ! _ob_validate_var_name "${archqual_var}"; then
					_ob_abort
				fi
				;;
			r)
				rel_var="${OPTARG}"
				if ! _ob_validate_var_name "${rel_var}"; then
					_ob_abort
				fi
				;;
			v)
				ver_var="${OPTARG}"
				if ! _ob_validate_var_name "${ver_var}"; then
					_ob_abort
				fi
				;;
			A)
				arches_var="${OPTARG}"
				if ! _ob_validate_var_name "${arches_var}"; then
					_ob_abort
				fi
				;;
			l)
				plats_var="${OPTARG}"
				if ! _ob_validate_var_name "${plats_var}"; then
					_ob_abort
				fi
				;;
			a)
				host_arch="${OPTARG}"
				;;
			p)
				host_plat="${OPTARG}"
				;;
			?)
				_ob_abort
				;;
		esac
	done
	shift $(($OPTIND - 1))

	dep="${1}"
	shift 1 || _ob_abort

	# pkg[:archqual] [(rel ver)] [\[arches\]] [<plats>]
	dep_re='s/^ *([^ \(\[<]+) *(\((<<|<=|=|>=|>>) *(.+)\))?'
	dep_re="${dep_re}"' *(\[(.+)\])? *(<(.+)>)? *$/\1\n\3\n\4\n\6\n\8/;'

	# BusyBox sed supports -r and (as of version 1.22.0) -E.
	dep="$(printf '%s\n' "${dep}" | sed -nr '
		H;
		${
			g;
			s/[\t\n]/ /g;
			'"${dep_re}"'
			p;
		};
		')"

	{
		IFS=':' read pkg archqual
		read rel || :
		read ver || :
		read arches || :
		read plats || :
	} <<-EOF
		${dep}
		EOF

	# Set the specified variables.
	for comp in pkg archqual rel ver arches plats; do
		comp_var="$(eval "printf '%s' \"\${${comp}_var}\"")"
		[ -z "${comp_var}" ] && continue
		eval "${comp_var}=\"\${${comp}}\""
	done

	if [ -n "${host_arch}" ] && ! ob_arch_is_concerned \
			"${host_arch}" "${arches}"; then
		return 0
	fi
	if [ -n "${host_plat}" ] && ! ob_plat_is_concerned \
			"${host_plat}" "${plats}"; then
		return 0
	fi

	printf '%s' "${pkg}"
	[ -n "${archqual}" ] && printf ':%s' "${archqual}"
	[ -n "${ver}" ] && printf ' (%s %s)' "${rel}" "${ver}"
	[ -z "${host_arch}" ] && [ -n "${arches}" ] && \
		printf ' [%s]' "${arches}"
	[ -z "${host_plat}" ] && [ -n "${plats}" ] && \
		printf ' [%s]' "${plats}"
	printf '\n'

	return 0
}

## @brief Reduce dependencies to a given architecture and platform
## @details \fBob_reduce_deps\fP reduces a list of dependencies to only those
##          that apply to a given architecture and platform.  A list is either a
##          "normal" list or a "union" list.  A normal list is an "AND" list
##          composed of "OR" lists, which in turn are composed of simple
##          dependencies.  A union list is an AND list composed of only simple
##          dependencies.  That is, a normal list is of the form
##          \fIdep\ |\ dep,\ dep\fP, and a union list is of the form
##          \fIdep,\ dep\fP.  The "Conflicts", "Provides", and "Replaces"
##          package relationships are union lists.
## @option -a host_arch The architecture to which dependencies should be
##                      reduced.  Required.
## @option -p host_plat The platform to which dependencies should be reduced. 
##                      Required.
## @option -u -         Treat \fIdeps\fP as a union list.
## @operand deps req The list of dependencies to reduce.
## @return Returns 0 on success.
## @stdout Prints the reduced list of dependencies.
## @pure yes This function has no side effects.
ob_reduce_deps()
{
	local opt=
	local host_arch=
	local host_plat=
	local deps=
	local dep_and=
	local dep_or=
	local dep_list=
	local dep_or_list=
	local dep=

	union='false'

	OPTIND=1
	while getopts 'a:p:u' opt; do
		case "${opt}" in
			a)
				host_arch="${OPTARG}"
				;;
			p)
				host_plat="${OPTARG}"
				;;
			u)
				union='true'
				;;
			?)
				_ob_abort
				;;
		esac
	done
	shift $(($OPTIND - 1))

	local deps="${1}"
	shift 1 || _ob_abort

	IFS=','
	for dep_and in ${deps}; do
		unset IFS
		if ! ${union}; then
			IFS='|'
			dep_or_list=
			for dep_or in ${dep_and}; do
				unset IFS
				dep="$(ob_parse_dep -a "${host_arch}" \
					-p "${host_plat}" "${dep_or}")"
				if [ -n "${dep}" ]; then
					if [ -n "${dep_or_list}" ]; then
						dep_or_list="${dep_or_list} | "
					fi
					dep_or_list="${dep_or_list}${dep}"
				fi
			done
			unset IFS
			if [ -n "${dep_or_list}" ]; then
				if [ -n "${dep_list}" ]; then
					dep_list="${dep_list}, "
				fi
				dep_list="${dep_list}${dep_or_list}"
			fi
		else
			dep="$(ob_parse_dep -a "${host_arch}" \
				-p "${host_plat}" "${dep_and}")"
			if [ -n "${dep}" ]; then
				if [ -n "${dep_list}" ]; then
					dep_list="${dep_list}, "
				fi
				dep_list="${dep_list}${dep}"
			fi
		fi
	done
	unset IFS

	printf '%s' "${dep_list}"

	return 0
}