#
# Copyright (c) 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023 Lucía Andrea Illanes Albornoz <lucia@luciaillanes.de>
# set +o errexit -o noglob -o nounset is assumed.
#

#
# rtl_check_prereqsV() - check for existence of list of commands
# @_rstatus:	out reference to status string
# @...:		commands list as positional parameters
#
# Returns:	zero (0) on success, non-zero (>0) on failure
#
rtl_check_prereqsV() {
	local	_rcp_rstatus="${1#\$}"	\
		_rcp_cmd="" _rcp_cmds_missing="" _rcp_rc=0;
	shift;

	for _rcp_cmd in "${@}"; do
		if ! which "${_rcp_cmd}" >/dev/null 2>&1; then
			_rcp_cmds_missing="${_rcp_cmds_missing:+${_rcp_cmds_missing} }${_rcp_cmd}";
		fi;
	done;
	if [ "${_rcp_cmds_missing:+1}" = 1 ]; then
		_rcp_rc=1;
		rtl_setrstatus "${_rcp_rstatus}" 'Error: missing prerequisite package(s): '"${_rcp_cmds_missing}";
	fi;
	return "${_rcp_rc}";
};

#
# rtl_clean_env() - unset environment variables w/ exceptions
# @_env_vars_except:	list of environment variables to keep
#
# Returns:		zero (0) on success, non-zero (>0) on failure
#
rtl_clean_env() {
	local	_rce_env_vars_except="${1}"	\
		_rce_env_var="" _rce_env_vars="" _rce_env_vars_unset="";

	_rce_env_vars="$(export | sed -ne '/^export/{s/^export //;s/=.*$//p}')";

	for _rce_env_var in ${_rce_env_vars}; do
		if [ "${_rce_env_var#DEFAULT_}" != "${_rce_env_var}" ]\
		|| [ "${_rce_env_var#PKG_}" != "${_rce_env_var}" ]; then
			rtl_lconcat \$_rce_env_vars_except "${_rce_env_var}";
		fi;
	done;
	rtl_lfilter2 \$_rce_env_vars \$_rce_env_vars_unset "${_rce_env_vars_except}";
	rtl_unset_vars ${_rce_env_vars_unset};

	return 0;
};

#
# rtl_get_cpu_count() - obtain CPU count
# @_rstatus:	out reference to status string
# @_rcount:	out reference to CPU count
#
# Returns:	zero (0) on success, non-zero (>0) on failure
#
rtl_get_cpu_count() {
	local	_rgcc_rstatus="${1#\$}" _rgcc_rcount="${2#\$}"		\
		_rgcc_line="" _rgcc_ncpus=0 _rgcc_rc=0 _rgcc_sname="";

	_rgcc_sname="$(uname -s 2>/dev/null)" || return 1;
	case "${_rgcc_sname}" in

	Linux)	if [ ! -e "/proc/cpuinfo" ]; then
			_rgcc_rc=1;
			rtl_setrstatus "${_rgcc_rstatus}" 'Error: /proc/cpuinfo non-existent.';
		else	while read -r _rgcc_line; do
				if rtl_match "${_rgcc_line}" "processor*:"; then
					: $((_rgcc_ncpus+=1));
				fi;
			done < /proc/cpuinfo;
			_rgcc_rc=0;
			rtl_setrstatus "${_rgcc_rstatus}" "";
		fi; ;;

	*)	_rgcc_rc=1;
		rtl_setrstatus "${_rgcc_rstatus}" 'Error: unknown platform \`'"${_rgcc_sname}"''\''.';
		;;

	esac;
	eval ${_rgcc_rcount}='${_rgcc_ncpus}';
	return "${_rgcc_rc}";
};

#
# rtl_get_var_unsafe() - get value of variable
# @_rvval:	out reference to variable value
# @[-u]:	optionally convert variable name to upper case
# @_vname:	variable name
#
# Returns:	zero (0) on success, non-zero (>0) on failure
# N.B.:		This function is *unsafe* and impossible to implement otherwise w/o filtering @_vname
#		and implicitly allows for code execution and other undefined behaviour via @_vname.
#		Do *not* pass untrusted input through @_vname.
#
rtl_get_var_unsafe() {
	local	_rgvu_rvval="${1#\$}"	\
		_rgvu_vname="";
	shift;

	if [ "x${1}" = "x-u" ]; then
		shift; _rgvu_vname="${1}"; rtl_toupper \$_rgvu_vname;
	else
		_rgvu_vname="${1}";
	fi;
	eval ${_rgvu_rvval}="\${${_rgvu_vname}:-}";
	return 0;
};

#
# rtl_kill_tree() - kill tree of processes
# @_rpids:	inout reference to list of PIDs
# @_pid:	top-level PID
# @_signal:	signal(7) to kill with
#
# Returns:	zero (0) on success, non-zero (>0) on failure
#
rtl_kill_tree() {
	local	_rkt_rpids="${1#\$}" _rkt_pid="${2}" _rkt_signal="${3:-TERM}"	\
		_rkt_pid_child="" _rkt_pids="";

	if _rkt_pids="$(pgrep -P "${_rkt_pid}")"\
	&& [ "${_rkt_pids:+1}" = 1 ]; then
		for _rkt_pid_child in ${_rkt_pids}; do
			rtl_kill_tree "${_rkt_rpids}" "${_rkt_pid_child}" "${_rkt_signal}";
		done;
	fi;
	if [ "${_rkt_pid:-0}" -ne "${$}" ]\
	&& kill "-${_rkt_signal}" "${_rkt_pid}" 2>/dev/null; then
		rtl_lconcat "${_rkt_rpids}" "${_rkt_pid}";
	fi;
	return 0;
};

#
# rtl_run_cmdlineV() - run command line w/ field splitting applied
# @_sep:	single non-zero, possibly multi-character, separator
# @_cmd:	command name
# @...:		command arguments as positional parameters
#
# Returns:	zero (0) on success, non-zero (>0) on failure
# N.B.:		This is required in situations where any of the command arguments 1) are passed from
#		and as a single, expanded parameter (e.g. "${MAKEFLAGS:-}") 2) the value of the parameter
#		contains multiple parameters separated by @_sep that must be passed as separate arguments
#		to @_cmd.
#
rtl_run_cmdlineV() {
	local	_rrc_sep="${1}" _rrc_cmd="${2}"	\
		_rrc_cmdline="" _rrc_rc="" IFS;
	shift 2;

	while [ ${#} -gt 0 ]; do
		[ "${1:+1}" = 1 ] &&\
			_rrc_cmdline="${_rrc_cmdline:+${_rrc_cmdline}${_rrc_sep}}${1}";
		shift;
	done;
	IFS="${_rrc_sep}"; ${_rrc_cmd} ${_rrc_cmdline}; _rrc_rc=$?;
	return ${_rrc_rc};
};

#
# rtl_set_var_from_spec() - set variable from name-value specification
# @_rstatus:	out reference to status string
# @_arg:	variable name-value specification separated by single "=" (e.g. name=value)
#
# Returns:	zero (0) on success, non-zero (>0) on failure
#
rtl_set_var_from_spec() {
	local	_rsvfs_rstatus="${1#\$}" _rsvfs_arg="${2}"	\
		_rsvfs_rc=0 _rsvfs_vname="" _rsvfs_vval="";

	_rsvfs_vname="${_rsvfs_arg%%=*}";
	_rsvfs_vval="${_rsvfs_arg#*=}";

	if [ "${_rsvfs_vval:+1}" != 1 ]; then
		_rsvfs_rc=1;
		rtl_setrstatus "${_rsvfs_rstatus}" 'empty value specified for \${'"${_rsvfs_vname}"'}.';
	else
		rtl_set_var_unsafe "${_rsvfs_vname}" "${_rsvfs_vval}";
	fi;
	return "${_rsvfs_rc}";
};

#
# rtl_set_var() - set variable from variables w/ template
# @_vars_set_vname:	list of variable names
# @_vname_dst:		variable name to set
# @_vname_src_tmpls:	variable name template (e.g. "DEFAULT PKG_")
#
# Returns:		zero (0) on success, non-zero (>0) on failure
#
rtl_set_var() {
	local	_rsv_vars_set_vname="${1}" _rsv_vname_dst="${2}" _rsv_vname_src_tmpls="${3}"	\
		_rsv_vars_set_old="" _rsv_vars_set_tmp="" _rsv_vname_src="" _rsv_vnames_src="";

	rtl_toupper2 \$_rsv_vname_src_tmpls \$_rsv_vnames_src;
	for _rsv_vname_src in ${_rsv_vnames_src}; do
		_rsv_vname_src="${_rsv_vname_src}_${_rsv_vname_dst}";
		eval _rsv_vval_src="\${${_rsv_vname_src}:-}";
		if [ "${_rsv_vval_src:+1}" = 1 ]; then
			eval PKG_${_rsv_vname_dst}='${_rsv_vval_src}';
			_rsv_vars_set_tmp="${_rsv_vars_set_tmp:+${_rsv_vars_set_tmp} }PKG_${_rsv_vname_dst}";
		fi;
	done;
	eval _rsv_vars_set_old="\${${_rsv_vars_set_vname}}";
	rtl_set_var_unsafe "${_rsv_vars_set_vname}" "${_rsv_vars_set_old:+${_rsv_vars_set_old} }${_rsv_vars_set_tmp}";

	return 0;
};

#
# rtl_set_var_unsafe() - set value of variable
# @[-u]:	optionally convert variable name to upper case
# @_vname:	variable name
# @_vval:	variable value
#
# Returns:	zero (0) on success, non-zero (>0) on failure
# N.B.:		This function is *unsafe* and impossible to implement otherwise w/o filtering @_vname
#		and implicitly allows for code execution and other undefined behaviour via @_vname.
#		Do *not* pass untrusted input through @_vname.
#
rtl_set_var_unsafe() {
	local _rsvu_vname="" _rsvu_vval="";
	if [ "x${1}" = "x-u" ]; then
		shift; _rsvu_vname="${1}"; _rsvu_vval="${2}"; rtl_toupper \$_rsvu_vname;
	else
		_rsvu_vname="${1}"; _rsvu_vval="${2}";
	fi;
	eval ${_rsvu_vname}='${_rsvu_vval}';
	return 0;
};

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