#
# set +o errexit -o noglob is assumed.
#

#
# exp_pkg_check_depends() - check single named package for unsatisfied dependencies
# @_pkg_complete:	list of completed packages
# @_pkg_name:		single package name
# @_pkg_wait:		list of in-progress packages
# @_restart_recursive:	optional flag specifiying either no dependency expansion (0,) dependency expansion (1,) dependency expansion and forcibly rebuild (2.)
#
# Return:		zero (0) given no outstanding dependencies, non-zero (>0) otherwise
#
exp_pkg_check_depends() {
	local	_pkg_complete="${1}" _pkg_name="${2}" _pkg_wait="${3}" _restart_recursive="${4}"	\
		_pkg_depends="" _pkg_name_depend="" _dependfl=0;
	if _pkg_depends="$(exp_pkg_expand_depends $(ex_rtl_get_var_unsafe -u "PKG_"${_pkg_name}"_DEPENDS"))"\
	&& [ -n "${_pkg_depends}" ]\
	&& ! [ -n "${_restart}" ] || [ "${_restart_recursive:-0}" -ge 1 ]; then
		for _pkg_name_depend in ${_pkg_depends}; do
			if ! ex_rtl_lmatch "${_pkg_complete}" "${_pkg_name_depend}"\
			|| ex_rtl_lmatch "${_pkg_wait}" "${_pkg_name_depend}"; then
				_dependfl=1; break;
			fi;
		done;
	fi;
	return "${_dependfl}";
};

#
# exp_pkg_dispatch_package() - dispatch single named packages
# @_dispatch_fn:	top-level dispatch function name
# @_group_name:		build group name
# @_pkg_name:		single package name
# @_restart_at:		optional comma-separated list of build steps at which to rebuild or ALL
#
# Return:		zero (0) on success, non-zero (>0) on failure, ${NJOBS}, ${PKG_COUNT}, ${PKG_NAMES}, and ${PKG_WAIT} may be mutated post-return.
#
exp_pkg_dispatch_package() {
	local _dispatch_fn="${1}" _group_name="${2}" _pkg_name="${3}" _restart_at="${4}";
	if "${_dispatch_fn}" start_pkg "${_group_name}" "${_pkg_name}" "$((${PKG_COUNT}+1))" "${PKG_COUNT_MAX}"; then
		: $((NJOBS+=1)); : $((PKG_COUNT+=1)); PKG_WAIT="$(ex_rtl_lconcat "${PKG_WAIT}" "${_pkg_name}")";
		(set +o errexit -o noglob; BUILD_IS_PARENT=0;
		if ex_pkg_env "${_group_name}" "${_pkg_name}" "${_restart_at}"; then
			ex_pkg_exec "${_dispatch_fn}" "${_group_name}" "${_pkg_name}" "${_restart_at}";
		else
			return "${?}";
		fi;) 1>"${BUILD_WORKDIR}/${_pkg_name}_stderrout.log" 2>&1 3>"${_pipe_path}" &
	else
		return "${?}";
	fi;
};

#
# exp_pkg_dispatch_packages() - dispatch set of packages
# @_dispatch_fn:	top-level dispatch function name
# @_group_name:		build group name
# @_njobs_max:		maximum count of simultaneous jobs
# @_pipe_path:		pathname to parent-child process FIFO
# @_pkg_complete:	list of completed packages
# @_restart_at:		optional comma-separated list of build steps at which to rebuild or ALL
# @_restart_recursive:	optional flag specifiying either no dependency expansion (0,) dependency expansion (1,) dependency expansion and forcibly rebuild (2.)
#
# Return:		zero (0) on success, non-zero (>0) on failure, ${NJOBS}, ${PKG_COUNT}, ${PKG_NAMES}, and ${PKG_WAIT} may be mutated post-return.
#
exp_pkg_dispatch_packages() {
	local	_dispatch_fn="${1}" _group_name="${2}" _njobs_max="${3}" _pipe_path="${4}"		\
		_pkg_complete="${5}" _restart_at="${6}" _restart_recursive="${7}"			\
		_njob=0 _pkg_depends="" _pkg_name="";
	for _njob in $(seq 1 $((${_njobs_max}-${NJOBS}))); do
		for _pkg_name in ${PKG_NAMES}; do
			if ! ex_rtl_lmatch "${_pkg_complete}" "${_pkg_name}"\
			&& ! ex_rtl_lmatch "${PKG_WAIT}" "${_pkg_name}"\
			&& exp_pkg_check_depends "${_pkg_complete}" "${_pkg_name}" "${PKG_WAIT}" "${_restart_recursive}"; then
				exp_pkg_dispatch_package "${_dispatch_fn}" "${_group_name}" "${_pkg_name}" "${_restart_at}"; break;
			fi;
		done;
	done;
};

#
# exp_pkg_expand_depends() - expand list of package names to amended and ordered list according to dependency constraints
# @${@}:		list of package names
#
# Return:		zero (0) on success, non-zero (>0) on failure, list of packages on stdout
#
exp_pkg_expand_depends() {
	local _pkg_depends="" _pkg_name="" _pkg_names="";
	for _pkg_name in "${@}"; do
		if _pkg_depends="$(ex_rtl_get_var_unsafe -u "PKG_${_pkg_name}_DEPENDS")"\
		&& [ -n "${_pkg_depends}" ]; then
			_pkg_depends="$(exp_pkg_expand_depends ${_pkg_depends})";
			_pkg_names="$(ex_rtl_lconcat "${_pkg_names}" "${_pkg_depends}")";
		fi;
		_pkg_names="$(ex_rtl_lconcat "${_pkg_names}" "${_pkg_name}")";
	done;
	echo "${_pkg_names}";
};

#
# exp_pkg_expand_packages() - expand build group name to list of packages ordered and filtered according to dependency and restart constraints
# @_group_name:		build group name
# @_restart:		optional comma-separated list of package names to rebuild
# @_restart_recursive:	optional flag specifiying either no dependency expansion (0,) dependency expansion (1,) dependency expansion and forcibly rebuild (2.)
#
# Return:		zero (0) on success, non-zero (>0) on failure, ${EX_PKG_NSKIPPED}, ${EX_PKG_NAMES}, and ${PKG_COMPLETE} set post-return.
#
exp_pkg_expand_packages() {
	local _group_name="${1}" _restart="${2}" _restart_recursive="${3}" _pkg_name="" _pkg_names="";
	if _pkg_names="$(ex_rtl_get_var_unsafe -u "${_group_name}_PACKAGES")"\
	&& [ -n "${_pkg_names}" ]; then
		if [ -n "${_restart}" ] && ! ex_rtl_lmatch "${_restart}" "ALL LAST"; then
			_pkg_names="$(ex_rtl_lsearch "${_pkg_names}" "${_restart}")";
		fi;
		if ! [ -n "${_restart}" ] || [ "${_restart_recursive:-0}" -ge 1 ]; then
			_pkg_names="$(ex_rtl_uniq $(exp_pkg_expand_depends ${_pkg_names}))";
		fi;
		for _pkg_name in ${_pkg_names}; do
			if [ -n "$(ex_rtl_get_var_unsafe -u "PKG_${_pkg_name}_DISABLED")" ]; then
				PKG_COMPLETE="$(ex_rtl_lconcat "${PKG_COMPLETE}" "${_pkg_name}")";
				: $((EX_PKG_NSKIPPED+=1)); _pkg_names="$(ex_rtl_lfilter "${_pkg_names}" "${_pkg_name}")";
			elif ex_pkg_state_test "${_pkg_name}" finish\
			&& ! ex_rtl_lmatch "${_restart}" "${_pkg_name}"\
			&& [ "${_restart_recursive:-0}" -ne 2 ]; then
				PKG_COMPLETE="$(ex_rtl_lconcat "${PKG_COMPLETE}" "${_pkg_name}")";
				: $((EX_PKG_NSKIPPED+=1)); _pkg_names="$(ex_rtl_lfilter "${_pkg_names}" "${_pkg_name}")";
			fi;
		done;
		EX_PKG_NAMES="${_pkg_names}"; return 0;
	fi;
};

#
# ex_pkg_dispatch() - dispatch a single build group
# @_dispatch_fn:	top-level dispatch function name
# @_group_name:		build group name
# @_njobs_max:		maximum count of simultaneous jobs
# @_restart:		optional comma-separated list of package names to rebuild
# @_restart_at:		optional comma-separated list of build steps at which to rebuild or ALL
# @_restart_recursive:	optional flag specifiying either no dependency expansion (0,) dependency expansion (1,) dependency expansion and forcibly rebuild (2.)
#
# Return:		zero (0) on success, non-zero (>0) on failure, ${EX_PKG_NAMES} and ${EX_PKG_NSKIPPED} set post-return.
#
ex_pkg_dispatch() {
	local	_dispatch_fn="${1}" _group_name="${2}" _njobs_max="${3}" _restart="${4}" _restart_at="${5}"			\
		_restart_recursive="${6}" _pipe_msg="" _pipe_path="${BUILD_WORKDIR}/build.fifo" _pkg_name=""			\
		_script_rc=0 NJOBS=0 PKG_COMPLETE="" PKG_COUNT=0 PKG_COUNT_MAX=0 PKG_NAMES="" PKG_WAIT=""; EX_PKG_NSKIPPED=0; EX_PKG_NAMES="";
	if "${_dispatch_fn}" start_group "${_group_name}" ""; then
		if ex_rtl_fileop mkdir "${BUILD_WORKDIR}"\
		&& ex_rtl_log_msg vnfo "Resolving \`${_group_name}' dependencies..."\
		&& exp_pkg_expand_packages "${_group_name}" "${_restart}" "${_restart_recursive}"\
		&& ex_rtl_log_msg vnfo "Resolved \`${_group_name}' dependencies."\
		&& PKG_COUNT_MAX="$(ex_rtl_llength "${EX_PKG_NAMES}")"\
		&& [ "${PKG_COUNT_MAX}" -gt 0 ]; then
			PKG_NAMES="${EX_PKG_NAMES}"; ex_rtl_fileop mkfifo "${_pipe_path}";
			while true; do
				while [ "${NJOBS:-0}" -gt 0 ] && read _pipe_msg; do
				case "${_pipe_msg%% *}" in
				done)	: $((NJOBS-=1)); _pkg_name="${_pipe_msg#done * }";
					"${_dispatch_fn}" finish_pkg ${_pipe_msg#done };
					PKG_COMPLETE="$(ex_rtl_lconcat "${PKG_COMPLETE}" "${_pkg_name}")";
					PKG_NAMES="$(ex_rtl_lfilter "${PKG_NAMES}" "${_pkg_name}")";
					PKG_WAIT="$(ex_rtl_lfilter "${PKG_WAIT}" "${_pkg_name}")";
					if [ -n "${PKG_NAMES}" ] && [ "${_script_rc}" -eq 0 ]; then
						if [ "${NJOBS}" -ne "${_njobs_max}" ]; then
							exp_pkg_dispatch_packages "${_dispatch_fn}" "${_group_name}" "${_njobs_max}"	\
								"${_pipe_path}" "${PKG_COMPLETE}" "${_restart_at}" "${_restart_recursive}";
						fi;
					elif [ "${NJOBS:-0}" -eq 0 ]; then
						break;
					fi; ;;
				fail)	: $((NJOBS-=1)); _script_rc=1;
					"${_dispatch_fn}" fail_pkg ${_pipe_msg#fail }; ;;
				step)	"${_dispatch_fn}" step_pkg ${_pipe_msg#step }; ;;
				esac; done <>"${_pipe_path}";
				if [ -n "${PKG_NAMES}" ] && [ "${_script_rc}" -eq 0 ]; then
					if [ "${NJOBS}" -ne "${_njobs_max}" ]; then
						exp_pkg_dispatch_packages "${_dispatch_fn}" "${_group_name}" "${_njobs_max}"	\
							"${_pipe_path}" "${PKG_COMPLETE}" "${_restart_at}" "${_restart_recursive}";
					fi;
				elif [ "${NJOBS:-0}" -eq 0 ]; then
					break;
				fi;
			done;
			ex_rtl_fileop rm "${_pipe_path}";
		fi;
		"${_dispatch_fn}" finish_group "${_group_name}" "";
	fi;
	return "${_script_rc}";
};

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