#!/bin/sh
#
# This script is used to derive compiler flags and filesystem paths
# necessary to utilize Lua, LuaJIT, and particular versions thereof in both
# simple and mixed installation environments.
#
# For usage help information use the -h switch.
#
# This script attempts to adhere strictly to POSIX shell specifications. The
# known non-POSIX features used are the path of the shell at the very first
# line of this script, the default compiler command name of `cc' instead of
# `c99', and the use of /dev/urandom for generating a random sandbox
# directory suffix. All of these can be override. For any other issues
# please contact the author.
#
# WARNING: When searching for a Lua interpreter this script may execute
# various utilities in an attempt to deduce their fitness and release
# version. By default this script will search for and execute utilities
# using the glob patterns luac* and lua*. But this script CANNOT GUARANTEE
# that executing such utilities, or any other utilities, either wittingly or
# unwittingly, will not result in your COMPUTER EXPLODING. You have been
# warned.
#
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
#
# Changelog:
#
# * 2013-08-02 - Published. Derived from an earlier script, lua.path,
# 	written for the cqueues project.
#
# * 2013-08-05 - Redirect stdin from /dev/null when probing so we don't
# 	freeze if a utility tries to read from stdin.
#
# 	chdir to a read-only directory by default to try to prevent creation
# 	of temporary files. These features address the issues of LuaTeX
# 	reading from stdin and creating a luatex.out file in the current
# 	working directory. By default a directory with a random suffix
# 	generated from /dev/urandom is placed in TMPDIR and removed on exit.
#
# 	If CPPFLAGS is empty and no -I options directly specified then set
# 	INCDIRS to "/usr/include:/usr/local/include".
#
# * 2013-08-07 - Add pkg-config support and refactor header probing to delay
# 	recursive searching.
#
# * 2013-09-09 - NetBSD's sh gets upset over the noclobber option and
# 	redirection to /dev/null, so use append operator. And check $#
# 	before iterating over a null parameter set with `do X; ...  done`
# 	when `set -u` is enabled--it complains about $@ being unset.
#
# * 2013-10-22 - Initial ldflags detection.
#
# * 2014-01-26 - Migrate CC vendor detection from external script.
#
# * 2014-09-29 - Add ldir and cdir modes which print install path by parsing
# 	package.path and package.cpath.
#
# * 2014-12-18 - Add -e GLOB option.
#
# 	Deprecate ldir and cdir modes.
#
# 	Add package.path and package.cpath to replace ldir and dir modes.
# 	Optional arguments to the new modes are preferred install paths,
# 	rather than globs for finding the lua utility path (use the new -e
# 	option, instead).
#
# * 2014-12-19 - Fix pkg-config version matching. The --modversion of
# 	the lua package might be stale. For example, it's 5.2.0 on Ubuntu
# 	14.04 even though the Lua release is 5.2.3.
#
# 	Use the interpreter path as a reference point when searching for
# 	headers. $(dirname ${LUA_PATH})/../include is a very likely location
# 	as bindir and includedir have the same prefix in most installations.
#
# * 2015-01-15 - Quote more command names and arguments. Still need to
# 	handle space characters in code that employs command substitution. I
# 	think we could handle all whitespace characters, including newlines,
# 	by using a control character in IFS and using --exec printf "%s\1" {}
# 	rather than -print with find(1).
#
# * 2015-01-19 - Add fix for LuaJIT's default package.cpath, which tends to
# 	hardcode /usr/local/lib/lua/5.1, ordered before the LuaJIT
# 	installation prefix.
#
# * 2015-07-14 - Add recursive glob function implemented in shell code
# 	and use instead of find(1).
#
# * 2016-03-18 - Fix bug in tryluac where a continue statement was used
# 	instead of return 0.
#
# * 2016-03-25 - Support ${CC} values with trailing flags, which invoke
# 	the compiler through env(1), or which otherwise are intended to
# 	expand as multiple words.
#
# 	OpenBSD 5.8 sh does not suppress strict errors within an eval
# 	invoked from an if condition compound-list. Workaround by changing
# 	trylua to return 0 on matching failure, like tryluainclude and
# 	tryluac do.
#
# 	Undeprecate ldir and cdir. The names are more intuitive and
# 	convenient as evidenced by the fact that I keep using them instead
# 	of package.path and package.cpath. Try to maintain backwards
# 	compatibility by using a simple heuristic to differentiate lua
# 	interpreter glob patterns from preferred install directory
# 	string.match expressions.
#
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
#
# Copyright (C) 2012-2016 William Ahern
#
# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
# DEALINGS IN THE SOFTWARE.
#
set -e # strict errors
set -u # don't expand unbound variables
set -f # disable pathname expansion
set -C # noclobber
\unalias -a # no command surprises
export LC_ALL=C # no locale headaches
unset IFS # no field splitting surprises
: ${TMPDIR:=/tmp} # sane TMPDIR
: ${CC:=cc}
unset LUA_PATH || true # interferes search for module install directory
unset LUA_CPATH || true

MYVERSION=20160325
MYVENDOR="william@25thandClement.com"


DEVRANDOM=/dev/urandom
SANDBOX="${TMPDIR}/${0##*/}-"

CPPDIRS=    # -I directories from CPPFLAGS
INCDIRS=
LDDIRS=     # -L directories from LDFLAGS
LIBDIRS=
BINDIRS=
RECURSE=no
MAXDEPTH=5  # maximum recursion depth
SHORTEST=   # continue searching until shortest pathname found
PKGCONFIG=  # path to pkg-config, found by `command -v` when -k option invoked
GLOB=       # -e GLOB expression for lua, luac, ldir, and cdir

GLOB_LUA="lua:lua[5-9]*:lua-[5-9]*:luajit*"
GLOB_LUAC="luac:luac[5-9]*:luac-[5-9]*"

API_MIN=500
API_MAX=999
API_VER=
API_DIR=

JIT_REQ=
JIT_MIN=20000
JIT_MAX=99999
JIT_VER=
JIT_DIR=

LIBLUA_VER=
LIBLUA_DIR=
LIBLUA_LIB=

LIBJIT_VER=
LIBJIT_DIR=
LIBJIT_LIB=

LUAC_PATH=
LUAC_VER=

LUA_PATH=
LUA_VER=


#
# warn FORMAT [...]
#
# Print message to original stderr.
#
exec 9>&2
warn() {
	printf "%s: %.0s${1}\n" "${0##*/}" "$@" >&9
}

#
# panic FORMAT [...]
#
# Print message to original stderr, then exit with failure.
#
panic() {
	warn "$@"
	exit 1
}


#
# parse CPPFLAGS -I or LDFLAGS -L directories
#
xdirs() {
	OPTC="${1:-I}"
	DIRS=

	set -- ${2:-}

	while [ $# -gt 0 ]; do
		case "${1}" in
		-${OPTC})
			shift

			if [ -n "${1:-}" ]; then
				DIRS="${DIRS}${DIRS:+:}${1}"
			fi

			;;
		-${OPTC}*)
			if [ "${1}" != "-${OPTC}" ]; then
				DIRS="${DIRS}${DIRS:+:}${1#-${OPTC}}"
			fi

			;;
		esac

		shift
	done

	printf -- "${DIRS}"
}

idirs() {
	xdirs "I" "${1:-}"
}

ldirs() {
	xdirs "L" "${1:-}"
}

# count ":"-delimited substrings
count() {
	IFS=:
	set -- ${1:-}
	unset IFS

	printf "$#"
}

# append to ":"-delimited string variable
append() {
	NAME=${1}
	eval VALUE="\${${NAME}}"
	shift

	IFS=:
	TMP="$*"

	IFS="\n"
	read -r "${NAME}" <<-EOF
		${VALUE:-}${VALUE:+:}${TMP}
	EOF
	unset IFS
}

#
# glob PATTERN [MAXDEPTH] [EXEC-COMMAND] [INTERNAL:GLOB-COUNT]
#
glob() {
	glob_N="${4:-0}"

	IFS=
	set +f
	for F in ${1}; do
		[ -e "${F}" ] || continue
		if eval "${3:-printf '%s\\n'} \"\${F}\""; then
			glob_N=$((${glob_N} + 1))
		fi
	done
	set -f
	unset IFS

	if [ "${2-0}" -gt 0 ]; then
		glob "${1%/*}/*/${1##*/}" "$((${2} - 1))" "${3:-}" "${glob_N}" || :
	fi

	[ "${glob_N}" -gt 0 ]
} # glob


#
# runcc [...]
#
# Wrapper for invoking ${CC}. Some build system include flags in ${CC},
# invoke the compiler through env(1), or employ other hacks.
#
# TODO: Optionally handle unescaping of words in a manner similar to how
# ${CC} would be evaluated from a make rule--typically by being passed
# through system(3).
#
runcc() {
	(unset IFS; exec ${CC} "$@")
}


#
# evalmacro PATH MACRO [REGEX] [SUBST]
#
# 	PATH   Header identifier--#include <PATH>
# 	MACRO  Macro identifier
# 	REGEX  Optional regex pattern to match macro evaluation result
# 	SUBST  Optional replacement expression
#
evalmacro() {
	printf "#include <$1>\n[===[$2]===]\n" \
	| runcc ${CPPFLAGS:-} -E - 2>>/dev/null \
	| sed -ne "
		s/^.*\\[===\\[ *\\(${3:-.*}\\) *\\]===\\].*$/${4:-\\1}/
		t Found
		d
		:Found
		p
		q
	"
}


#
# testsym PATH NAME
#
# Test whether global symbol NAME exists in object file at PATH. Exits with
# 0 (true) when found, non-0 (false) otherwise.
#
testsym() {
	# NOTE: No -P for OpenBSD nm(1), but the default output format is
	# close enough. Section types always have a leading and trailing
	# space. U section type means undefined. On AIX [VWZ] are weak
	# global symbols. Solaris and OS X have additional symbol types
	# beyond the canonical POSIX/BSD types, all of which are uppercase
	# and within [A-T].
	(nm -Pg ${1} 2>>/dev/null || nm -g 2>>/dev/null) \
	| sed -ne '/ [A-T] /p' \
	| grep -q "${2}"
}


tryluainclude() {
	V="$(evalmacro "${1}" LUA_VERSION_NUM '[0123456789][0123456789]*')"
	: ${V:=0}

	if [ "${1%/*}" != "${1}" ]; then
		D="${1%/*}"

		# cleanup after Solaris directory prune trick
		if [ "${D##*/./}" != "${D}" ]; then
			D="${D%%/./*}/${D##*/./}"
		else
			D="${D%/.}"
		fi
	else
		D=
	fi

	[ "$V" -gt 0 -a "$V" -ge "${API_VER:-0}" ] || return 0

	[ "$V" -gt "${API_VER:-0}" -o "${#D}" -lt "${#API_DIR}" -o \( "${JIT_REQ}" = "yes" -a "${JIT_VER:-0}" -lt "${JIT_MAX}" \) ] || return 0

	[ "$V" -ge "${API_MIN}" -a "$V" -le "${API_MAX}" ] || return 0

	if [ -n "${JIT_REQ}" ]; then
		J="$(evalmacro "${1%%lua.h}luajit.h" LUAJIT_VERSION_NUM '[0123456789][0123456789]*')"
		: ${J:=0}

		if [ "${JIT_REQ}" = "skip" ]; then
			[ "${J}" -eq 0 ] || return 0
		elif [ "${JIT_REQ}" = "yes" ]; then
			[ "$J" -ge "${JIT_VER:-0}" ] || return 0
			[ "$J" -gt "${JIT_VER:-0}" -o "${#D}" -lt "${#JIT_DIR}" ] || return 0
			[ "$J" -ge ${JIT_MIN} ] || return 0
			[ "$J" -le "${JIT_MAX}" ] || return 0

			JIT_VER="$J"
			JIT_DIR="$D"
		fi
	fi

	API_VER="$V"
	API_DIR="$D"
}


#
# foundversion
#
# true if found the best (maximum) possible version, false otherwise
#
foundversion() {
	if [ "${API_VER:-0}" -lt "${API_MAX}" ]; then
		return 1
	fi

	if [ "${JIT_REQ}" = "yes" -a "${JIT_VER:-0}" -lt "${JIT_MAX}" ]; then
		return 1
	fi

	if [ "${SHORTEST}" = "yes" ]; then
		return 1
	fi

	return 0
}


#
# luapc
#
# wrapper around `pkg-config ... LIB`, where LIB is derived by
# searching for all libraries with "lua" in the name that have a
# --modversion equal to the release version printed by ${LUA_PATH} -v.
#
LUAPC_LIB=

luapc() {
	[ -n "${LUA_PATH}" ] || return 0

	[ -n "${PKGCONFIG}" ] || return 0

	# find pkg-config library name
	if [ -z "${LUAPC_LIB}" ]; then
		V="$("${LUA_PATH}" -v </dev/null 2>&1 | head -n1 | sed -ne 's/^Lua[^ ]* \([0123456789][0123456789]*\(\.[0123456789][0123456789]*\)*\).*/\1/p')"

		[ -n "${V}" ] || return 0

		V_N=$(mmp2num "${V}")

		for LIB in $("${PKGCONFIG}" --list-all </dev/null 2>>/dev/null | sed -ne 's/^\(lua[^ 	]*\).*/\1/p'); do
			M="$("${PKGCONFIG}" --modversion ${LIB} || true)"

			# break immediately on exact match
			if [ "${V}" = "${M}" ]; then
				LUAPC_LIB="${LIB}"

				break
			fi

			#
			# NOTE: On Ubuntu 14.04 pkg-config --modversion
			# lua5.2 prints 5.2.0 even though the release
			# version is 5.2.3 (what lua5.2 -v prints).
			#
			# If the major.minor components match, then
			# tentatively use that package name.
			#
			M_N=$(mmp2num "${M}" 0 0 0)

			if [ "$((${V_N} / 100))" -eq "$((${M_N} / 100))" ]; then
				LUAPC_LIB="${LIB}"
			fi
		done

		[ -n "${LUAPC_LIB}" ] || return 0
	fi

	${PKGCONFIG} "$@" "${LUAPC_LIB}" </dev/null 2>>/dev/null || true
}


#
# findinstalldir  package.path|package.cpath [preferred-path ...]
#
findinstalldir() {
	V_DIR=$((${LUA_VER} / 100 % 100)).$((${LUA_VER} % 100))

	if [ "${1}" = "package.cpath" -o "${1}" = "cdir" ]; then
		ARRAY="package.cpath"

		DIR="$(luapc --variable INSTALL_CMOD)"
		[ -n "${DIR}" ] && set -- "$@" "${DIR}"

		DIR="$(luapc --variable INSTALL_LIB)"
		[ -n "${DIR}" ] && set -- "$@" "${DIR}/lua/${V_DIR}"

		DIR="$(luapc --variable libdir)"
		[ -n "${DIR}" ] && set -- "$@" "${DIR}/lua/${V_DIR}"

		DIR="$(luapc --variable prefix)"
		[ -n "${DIR}" ] && set -- "$@" "${DIR}/lib/lua/${V_DIR}"

		# LuaJIT installations tend to include
		# /usr/local/lib/lua/5.1 as one of the first paths, ordered
		# before the LuaJIT installation prefix, and regardless of
		# whether there exists a /usr/local/lib/lua/5.1.
		set -- "$@" "${LUA_PATH}/../../lib/lua/${V_DIR}"
		set -- "$@" "${LUA_PATH}/../../lib/*/lua/${V_DIR}" # e.g. lib/x86_64-linux-gnu
	else
		ARRAY="package.path"

		DIR="$(luapc --variable INSTALL_LMOD)"
		[ -n "${DIR}" ] && set -- "$@" "${DIR}"

		DIR="$(luapc --variable prefix)"
		[ -n "${DIR}" ] && set -- "$@" "${DIR}/share/lua/${V_DIR}"

		# See above LuaJIT note. Although the built-in package.path
		# usually orders the LuaJIT installation prefix first.
		set -- "$@" "${LUA_PATH}/../../share/lua/${V_DIR}"
	fi

	shift

	if [ $# -eq 0 ]; then
		set -- "/nonexistent" # cannot expand empty $@ on some implementations
	fi

	"${LUA_PATH}" - "$@" <<-EOF
		--
		-- actual pkg-config variable on Ubuntu 14.04
		--
		-- 	/usr//share/lua/5.1
		--
		local function fixpath(path)
			local stack = { path:match"^/" and "" or "." }

			for ent in path:gmatch"([^/]+)" do
				if ent == ".." and #stack > 1 then
					stack[#stack] = nil
				elseif ent ~= "." then
					stack[#stack + 1] = ent
				end
			end

			return table.concat(stack, "/")
		end

		local function topattern(path)
			if string.match(path, "*") then
				path = string.gsub(path, "%%", "%%")
				return string.gsub(path, "*", "[^/]+")
			end
		end

		local dirs = { }

		for dir in ${ARRAY}:gmatch"([^;?]+)/" do
			dir = fixpath(dir)

			if dir ~= "." then
				dirs[#dirs + 1] = dir
			end
		end

		for _, arg in ipairs{ ... } do
			arg = fixpath(arg)

			local pat = topattern(arg)

			for _, dir in ipairs(dirs) do
				if arg == dir then
					print(dir)
					os.exit(0)
				elseif pat and string.match(dir, pat) then
					print(dir)
					os.exit(0)
				end
			end
		end

		if dirs[1] then
			print(dirs[1])
			os.exit(0)
		else
			os.exit(1)
		end
	EOF
}


#
# findversion
#
findversion() {
	tryluainclude "lua.h"

	if foundversion; then
		return 0
	fi


	# iterate through CPPFLAGS to probe different precedence
	if [ "${API_VER:-0}" -lt "${API_MAX}" ]; then
		IFS=:
		set -- ${CPPDIRS}
		unset IFS

		if [ $# -gt 0 ]; then
			for D; do
				tryluainclude "${D}/lua.h"

				if foundversion; then
					return 0
				fi
			done
		fi
	fi


	if [ -n "${PKGCONFIG}" ]; then
		PKGFLAGS="$("${PKGCONFIG}" --list-all </dev/null 2>>/dev/null | sed -ne 's/^\(lua[^ 	]*\).*/\1/p' | xargs -- ${PKGCONFIG} --cflags 2>>/dev/null | cat)"
		PKGDIRS="$(idirs "${PKGFLAGS}")"

		IFS=:
		set -- ${PKGDIRS}
		unset IFS

		if [ $# -gt 0 ]; then
			for D; do
				tryluainclude "${D}/lua.h"

				if foundversion; then
					return 0
				fi
			done
		fi
	fi


	IFS=:
	set -- ${INCDIRS}
	unset IFS

	if [ $# -gt 0 ]; then
		for D; do
			tryluainclude "${D}/lua.h"

			if foundversion; then
				return 0
			fi
		done
	fi


	if [ "${RECURSE}" != "yes" ]; then
		[ "${API_VER:-0}" -gt 0 ]
		return $?
	fi


	# recurse into CPPDIRS
	IFS=:
	set -- ${CPPDIRS}
	unset IFS

	if [ $# -gt 0 ]; then
		for D; do
			glob "${D}/lua.h" "${MAXDEPTH}" tryluainclude || :

			if foundversion; then
				return 0
			fi
		done
	fi


	# recurse into INCDIRS
	IFS=:
	set -- ${INCDIRS}
	unset IFS

	if [ $# -gt 0 ]; then
		for D; do
			glob "${D}/lua.h" "${MAXDEPTH}" tryluainclude || :

			if foundversion; then
				return 0
			fi
		done
	fi


	# if we can find the lua interpreter, use it as a reference for
	# header locations.
	if findlua; then
		D="${LUA_PATH%/*}"
		D="${D%/*}/include"

		if [ -d "${D}" ]; then
			glob "${D}/lua.h" "${MAXDEPTH}" tryluainclude || :

			if foundversion; then
				return 0
			fi
		fi
	fi

	[ "${API_VER:-0}" -gt 0 ]
}


#
# Unlike API version checking, this is less likely to be accurately forward
# compatible.
#
trylib() {
	testsym "${1}" "lua_newstate" || return 1

	# exclude C++
	[ "${1#*++}" = "${1}" ] || return 1

	V=0
	J=0
	D=
	F="${1##*/}"
	L=

	if [ "${1%/*}" != "${1}" ]; then
		D="${1%/*}"

		# cleanup after Solaris directory prune trick
		if [ "${D##*/./}" != "${D}" ]; then
			D="${D%%/./*}/${D##*/./}"
		else
			D="${D%/.}"
		fi
	fi

	L="${F#lib}"
	L="${L%.so}"
	L="${L%.a}"
	L="${L%.dylib}"


	# FIXME: need more versioning tests
	if testsym "${1}" "lua_getfenv"; then
		V=501
	elif testsym "${1}" "lua_yieldk"; then
		if testsym "${1}" "lua_getctx"; then
			V=502
		else
			V=503
		fi
	else
		return 1
	fi

	[ "$V" -gt 0 -a "$V" -ge "${LIBLUA_VER:-0}" ] || return 1

	[ "$V" -gt "${LIBLUA_VER:-0}" -o "${#D}" -lt "${#LIBLUA_DIR}" -o \( "${JIT_REQ}" = "yes" -a "${LIBJIT_VER:-0}" -lt "${JIT_MAX}" \) ] || return 1

	[ "$V" -ge "${API_MIN}" -a "$V" -le "${API_MAX}" ] || return 1


	if [ -n "${JIT_REQ}" ]; then
		# FIXME: need more versioning tests
		if testsym "${1}" "luaopen_jit"; then
			J=20000
		fi

		if [ "${JIT_REQ}" = "skip" ]; then
			[ "${J}" -eq 0 ] || return 1
		elif [ "${JIT_REQ}" = "yes" ]; then
			[ "$J" -ge "${LIBJIT_VER:-0}" ] || return 1
			[ "$J" -gt "${LIBJIT_VER:-0}" -o "${#D}" -lt "${#LIBJIT_DIR}" ] || return 1
			[ "$J" -ge ${JIT_MIN} ] || return 1
			[ "$J" -le "${JIT_MAX}" ] || return 1

			LIBJIT_VER="$J"
			LIBJIT_DIR="$D"
			LIBJIT_LIB="$L"
		fi
	fi

	LIBLUA_VER="$V"
	LIBLUA_DIR="$D"
	LIBLUA_LIB="$L"
}


#
# foundlib
#
# true if found the best (maximum) possible version, false otherwise
#
foundlib() {
	if [ "${LIBLUA_VER:-0}" -lt "${API_MAX}" ]; then
		return 1
	fi

	if [ "${JIT_REQ}" = "yes" -a "${LIBJIT_VER:-0}" -lt "${JIT_MAX}" ]; then
		return 1
	fi

	if [ "${SHORTEST}" = "yes" ]; then
		return 1
	fi

	return 0
}


findlib() {
	if [ -n "${PKGCONFIG}" ]; then
		PKGFLAGS="$("${PKGCONFIG}" --list-all </dev/null 2>>/dev/null | sed -ne 's/^\(lua[^ 	]*\).*/\1/p' | xargs -- ${PKGCONFIG} --libs 2>>/dev/null | cat)"
		PKGDIRS="$(ldirs "${PKGFLAGS}")"
		PKGDIRS="${PKGDIRS}${PKGDIRS:+:}/lib:/usr/lib:/usr/local/lib"
		NUMDIRS="$(count "${PKGDIRS}")"
		PKGLIBS="$(xdirs "l" "${PKGFLAGS}")"
		NUMLIBS="$(count "${PKGLIBS}")"
		ALLDIRS="${PKGDIRS}${PKGLIBS:+:}${PKGLIBS}"

		IFS=:
		set -- ${ALLDIRS}
		unset IFS

		I=1
		while [ $I -le ${NUMDIRS} ]; do
			K=$((1 + ${NUMDIRS}))
			while [ $K -le $# ]; do
				findlib_L=$(eval "printf \${$I}")
				findlib_l=$(eval "printf \${$K}")

				#printf -- "I=$I K=$K $findlib_L/lib$findlib_l*.*\n"

				glob "${findlib_L}/lib${findlib_l}*.*" 0 trylib || :

				if foundlib; then
					return 0;
				fi

				glob "${findlib_L}/lib${findlib_l}*.*" ${MAXDEPTH} trylib || :

				if foundlib; then
					return 0;
				fi

				K=$(($K + 1))
			done
			I=$(($I + 1))
		done
	fi

	ALLDIRS="${LDDIRS}${LDDIRS:+:}${LIBDIRS}"

	IFS=:
	set -- ${ALLDIRS}
	unset IFS

	for findlib_D; do
		glob "${findlib_D}/liblua*.*" "${MAXDEPTH}" trylib || :

		if foundlib; then
			return 0
		fi
	done

	# if we can find the lua interpreter, use it as a reference for
	# library locations.
	if findlua; then
		findlib_D="${LUA_PATH%/*}"
		findlib_D="${findlib_D%/*}/lib"

		if [ -d "${findlib_D}" ]; then
			glob "${findlib_D}/liblua*.*" "${MAXDEPTH}" trylib || :

			if foundlib; then
				return 0
			fi
		fi
	fi
}


# check setuid and setgid mode
safeperm() {
	[ -f "$1" -a ! -u "$1" -a ! -g "$1" ]
}


tryluac() {
	tryluac_F="${1}"

	[ -x "${tryluac_F}" ] && safeperm "${tryluac_F}" || return 0

	tryluac_V="$("${tryluac_F}" -v </dev/null 2>&1 | head -n1 | sed -ne 's/^Lua \([0123456789][0123456789]*\.[0123456789][0123456789]*\).*/\1/p')"
	: ${tryluac_V:=0}
	tryluac_V="$((${tryluac_V%%.*} * 100 + ${tryluac_V##*.} % 100))"

	[ "${tryluac_V}" -gt 0 -a "${tryluac_V}" -ge "${LUAC_VER:-0}" ] || return 0

	[ "${tryluac_V}" -gt "${LUAC_VER:-0}" -o "${#tryluac_F}" -lt "${#LUAC_PATH}" ] || return 0

	[ "${tryluac_V}" -ge "${API_MIN}" -a "${tryluac_V}" -le "${API_MAX}" ] || return 0

	printf "return true" 2>>/dev/null | ${tryluac_F} -p - </dev/null >>/dev/null 2>&1 || return 0

	LUAC_PATH="${tryluac_F}"
	LUAC_VER="${tryluac_V}"
}

#
# foundluac
#
# true if found the best (maximum) possible version, false otherwise
#
foundluac() {
	if [ "${LUAC_VER:-0}" -lt "${API_MAX}" ]; then
		return 1
	fi

	if [ "${SHORTEST}" = "yes" ]; then
		return 1
	fi

	return 0
}

findluac() {
	if [ $# -eq 0 ]; then
		IFS=:
		set -- ${GLOB:-${GLOB_LUAC}}
		unset IFS
	fi

	for findluac_G; do
		IFS=:
		for findluac_D in ${PATH}; do
			unset IFS

			glob "${findluac_D}/${findluac_G}" 0 tryluac || :

			if foundluac; then
				return 0
			fi
		done

		IFS=:
		for findluac_D in ${BINDIRS}; do
			unset IFS

			glob "${findluac_D}/${findluac_G}" "${MAXDEPTH}" tryluac || :

			if foundluac; then
				return 0
			fi
		done

		unset IFS
	done

	[ "${LUAC_VER:-0}" -gt 0 ] && [ "${#LUAC_PATH}" -gt 0 ]
}


isinteger() {
	I="${1}"

	[ "${#I}" -gt 0 ] || return 1

	while [ "${#I}" -gt 0 ]; do
		if [ "${I##[0123456789]}" = "${I}" ]; then
			return 1
		fi

		I=${I##[0123456789]}
	done

	return 0
}


checkints() {
	while [ $# -gt 0 ]; do
		if ! isinteger "${1}"; then
			warn "%s: not a number" "${1}"
			return 1
		fi

		shift
	done
}


# Only major.minor for matching LUA_VERSION_NUM in lua.h. Also, _VERSION
# only includes major.minor.
lua2num() {
	M=0
	m="${2:-0}"

	IFS=.
	set -- ${1}
	unset IFS

	M=${1:-${M}}
	m=${2:-${m}}

	checkints $M $m

	printf "$((${M} * 100 + ${m}))\n"
}


# All major.minor.patch for matching LUAJIT_VERSION_NUM in luajit.h.
jit2num() {
	M=0
	m="${2:-0}"
	p="${3:-0}"

	IFS=.
	set -- ${1}
	unset IFS

	M=${1:-${M}}
	m=${2:-${m}}
	p=${3:-${p}}

	checkints $M $m $p

	printf "$((${M} * 10000 + ${m} * 100 + ${p}))\n"
}


mmp2num() {
	M="${2:-0}"
	m="${3:-0}"
	p="${4:-0}"

	IFS=".+-_"
	set -- ${1}
	unset IFS

	if isinteger "${1:-}"; then
		M=${1}
	fi

	if isinteger "${2:-}"; then
		m=${2}
	fi

	if isinteger "${3:-}"; then
		p=${3}
	fi

	checkints $M $m $p

	printf "$((${M} * 10000 + ${m} * 100 + ${p}))\n"
}


trylua() {
	trylua_F="${1}"
	[ -x "${trylua_F}" ] && safeperm "${trylua_F}" || return 0

	trylua_V="$("${trylua_F}" -e 'print(string.match(_VERSION, [[[%d.]+]]))' </dev/null 2>>/dev/null | head -n1 | sed -ne 's/^\([0123456789][0123456789]*\.[0123456789][0123456789]*\).*/\1/p')"
	: ${trylua_V:=0}
	trylua_V="$((${trylua_V%%.*} * 100 + ${trylua_V##*.} % 100))"

	[ "${trylua_V}" -gt 0 -a "${trylua_V}" -ge "${LUA_VER:-0}" ] || return 0

	[ "${trylua_V}" -gt "${LUA_VER:-0}" -o "${#trylua_F}" -lt "${#LUA_PATH}" ] || return 0

	[ "${trylua_V}" -ge "${API_MIN}" -a "${trylua_V}" -le "${API_MAX}" ] || return 0

	if [ -n "${JIT_REQ}" ]; then
		J="$("${trylua_F}" -v </dev/null 2>&1 | head -n1 | sed -ne 's/^LuaJIT \([0123456789][0123456789]*\.[0123456789][0123456789]*\.[0123456789][0123456789]*\).*/\1/p')"
		J="$(jit2num ${J:-0})"

		if [ "${JIT_REQ}" = "skip" ]; then
			[ "${J}" -eq 0 ] || return 0
		elif [ "${JIT_REQ}" = "yes" ]; then
			[ "${J}" -gt 0 ] || return 0
			[ "${J}" -ge "${JIT_MIN}" ] || return 0
			[ "${J}" -le "${JIT_MAX}" ] || return 0
		fi
	fi

	LUA_PATH="${trylua_F}"
	LUA_VER="${trylua_V}"
}

#
# foundlua
#
# true if found the best (maximum) possible version, false otherwise
#
foundlua() {
	if [ "${LUA_VER:-0}" -lt "${API_MAX}" ]; then
		return 1
	fi

	if [ "${SHORTEST}" = "yes" ]; then
		return 1
	fi

	return 0
}

findlua() {
	if [ $# -eq 0 ]; then
		IFS=:
		set -- ${GLOB:-${GLOB_LUA}}
		unset IFS
	fi

	for findlua_G; do
		IFS=:
		for findlua_D in ${PATH}; do
			unset IFS

			glob "${findlua_D}/${findlua_G}" 0 trylua || :

			if foundlua; then
				return 0
			fi
		done

		IFS=:
		for findlua_D in ${BINDIRS}; do
			unset IFS

			glob "${findlua_D}/${findlua_G}" "${MAXDEPTH}" trylua || :

			if foundlua; then
				return 0
			fi
		done

		unset IFS
	done

	[ "${LUA_VER:-0}" -gt 0 ] && [ "${#LUA_PATH}" -gt 0 ]
}


ccname() {
	runcc -E - <<-EOF | awk '/sunpro/||/clang/||/gcc/||/other/{ print $1; exit; }'
		#if defined __SUNPRO_C
		sunpro
		#elif defined __clang__
		clang
		#elif defined __GNUC__
		gcc
		#else
		other
		#endif
	EOF
}


usage() {
	cat <<-EOF
	usage: ${0##*/} [-I:L:P:d:De:krm:xsv:j:JVh] cppflags|version|lua|luac|...
	  -I PATH      additional search directory for includes
	  -L PATH      additional search directory for libraries
	  -P PATH      additional search directory for binaries
	  -d PATH      use PATH as sandbox directory; a random 16 byte suffix is
	               generated from /dev/urandom and the directory removed on exit
	               unless a trailing "/" is present
	               (default sandbox is \$TMPDIR/${0##*/}-XXXXXXXXXXXXXXXX)
	  -D           do not create a sandbox
	  -e GLOB      glob pattern for finding utilities (lua, luac, etc)
	  -k           query pkg-config if available
	  -r           recursively search directories
	  -m MAXDEPTH  limit recursion to MAXDEPTH
	  -s           find shortest pathname, otherwise print first best match
	  -v VERSION   require specific Lua version or range
	               (e.g. "5.1" or "5.1-5.2")
	  -j VERSION   require specific LuaJIT version or range
	               (e.g. "2.0.1"; empty ranges like "-" force any LuaJIT version)
	  -J           skip LuaJIT if encountered
	  -V           print this script's version information
	  -h           print this usage message

	  cppflags       print derived additional CPPFLAGS necessary
	  version        print derived Lua API version from cppflags discovery
	  ldflags        print derived additional LDFLAGS necessary (TODO)
	  libs	         print derived additional LIBS necessary (TODO)
	  libversion     print derived Lua API version from ldflags/libs discovery
	  luac           print path to luac utility ($(printf "${GLOB_LUA}" | tr ':' ' '))
	  lua            print path to lua interpreter ($(printf "${GLOB_LUAC}" | tr ':' ' '))
	  package.path   print preferred module install path
	  package.cpath  print preferred C module install path
	  ccname         print CC name (e.g. sunpro, clang, gcc)
	  evalmacro      run internal macro evaluator for debugging
	  testsym        run internal library symbol reader for debugging

	This utility is used to derive compiler flags and filesystem paths
	necessary to utilize Lua, LuaJIT, and particular versions thereof.
	On success it prints the requested information and exits with 0,
	otherwise it fails with an exit status of 1.

	Note that cppflags may not print anything if no additional flags are
	required to compile against the requested API version.

	When searching, the highest Lua version is preferred. Searching
	stops once the highest version in the allowable range is found
	unless the -s flag is specified.

	LuaJIT is treated like any other Lua installation. If an explicit
	LuaJIT version or range is specified, then only LuaJIT installations
	will match. To exclude LuaJIT entirely use the -J switch.

	This utility processes the environment variables CC, CPPFLAGS,
	LDFLAGS, and PATH if present. If recursion is requested, then
	directories specified in CPPFLAGS, LDFLAGS, and PATH are also
	recursed.

	If the environment variable CPPFLAGS is empty and no -I options are
	specified directly, then /usr/include and /usr/local/include are
	used when probing for cppflags and API version.

	Report bugs to <william@25thandClement.com>
	EOF
}


version() {
	cat <<-EOF
	luapath $MYVERSION
	vendor  $MYVENDOR
	release $MYVERSION
	EOF
}


while getopts I:L:P:d:De:krm:xsv:j:JVh OPT; do
	case "${OPT}" in
	I)
		INCDIRS="${INCDIRS:-}${INCDIRS:+:}${OPTARG}"
		;;
	L)
		LIBDIRS="${LIBDIRS:-}${LIBDIRS:+:}${OPTARG}"
		;;
	P)
		BINDIRS="${BINDIRS:-}${BINDIRS:+:}${OPTARG}"
		;;
	d)
		SANDBOX="${OPTARG}"
		;;
	D)
		SANDBOX=
		;;
	e)
		GLOB="${GLOB:-}${GLOB:+:}${OPTARG}"
		;;
	k)
		PKGCONFIG="$(command -v pkg-config || true)"
		;;
	r)
		RECURSE=yes
		;;
	m)
		if [ "${#OPTARG}" -eq 0 -o -n "${OPTARG##[0123456789]}" ]; then
			panic "%s: invalid maxdepth" "${OPTARG}"
		fi

		MAXDEPTH="${OPTARG}"
		;;
	x)
		#
		# NOTE: This option was
		#
		# 	-x  do not cross device mounts when recursing
		#
		# but is currently unsupported as our built-in glob function
		# does not implement this functionality. Previously this
		# option caused -xdev to be added to invocations of find(1).
		;;
	s)
		SHORTEST=yes
		;;
	v)
		MIN=${OPTARG%%[,:-]*}
		MAX=${OPTARG##*[,:-]}

		API_MIN="$(lua2num ${MIN:-0} 0)"
		API_MAX="$(lua2num ${MAX:-99} 99)"

		if [ "${API_MIN}" -gt "${API_MAX}" ]; then
			panic "%s: invalid version range" "${OPTARG}"
		fi

		;;
	j)
		MIN=${OPTARG%%[,:-]*}
		MAX=${OPTARG##*[,:-]}

		JIT_MIN="$(jit2num ${MIN:-0} 0 0)"
		JIT_MAX="$(jit2num ${MAX:-99} 99 99)"

		if [ "${JIT_MIN}" -gt "${JIT_MAX}" ]; then
			panic "%s: invalid version range" "${OPTARG}"
		fi

		JIT_REQ=yes
		;;
	J)
		JIT_REQ=skip
		;;
	V)
		version
		exit 0
		;;
	h)
		usage
		exit 0
		;;
	*)
		usage >&2
		exit 1
		;;
	esac
done

shift $(($OPTIND - 1))


[ "${RECURSE}" = "yes" ] || MAXDEPTH=0


for U in "${CC}" grep od rm rmdir sed xargs; do
	! command -v "${U}" >>/dev/null 2>&1 || continue

	# ${CC} might have trailing flags or invoke the compiler through env
	! command -v "${U%% *}" >>/dev/null 2>&1 || continue

	warn "%s: command not found" "${U}"
done


if [ -n "${SANDBOX}" ]; then
	if [ "${SANDBOX}" = "${SANDBOX%/}" ]; then
		if [ ! -c "${DEVRANDOM}" ]; then
			# TODO: expand DEVRANDOM into set of different possibilities to check
			panic "%s: no character random device available" "${DEVRANDOM}"
		fi

		TMP="${SANDBOX}$(od -An -N8 -tx1 < ${DEVRANDOM} 2>>/dev/null | tr -d ' 	')"

		if [ ${#TMP} -ne $((${#SANDBOX} + 16)) ]; then
			panic "%s: unable to generate random suffix" "${SANDBOX}"
		fi

		SANDBOX="${TMP}"

		trap "cd .. && rm -f -- ${SANDBOX}/* && rmdir -- ${SANDBOX}" EXIT
	fi

	if [ ! -d "${SANDBOX}" ]; then
		OMASK="$(umask)"
		umask 0777
		mkdir -m0550 -- "${SANDBOX}" || exit 1
		umask ${OMASK}
	fi

	cd ${SANDBOX}
fi


CPPDIRS="$(idirs "${CPPFLAGS:-}")"

if [ -z "${CPPDIRS}" -a -z "${INCDIRS}" ]; then
	INCDIRS="/usr/include:/usr/local/include"
fi


LDDIRS="$(ldirs "${LDFLAGS:-}")"

if [ -z "${LDDIRS}" -a -z "${LIBDIRS}" ]; then
	LIBDIRS="/lib:/usr/lib:/usr/local/lib"
fi


case "${1:-}" in
cppflags)
	findversion || exit 1

	[ "${API_VER:-0}" -gt 0 ] || exit 1

	[ -z "${API_DIR:-}" ] || printf -- "-I${API_DIR}\n"

	;;
version)
	findversion || exit 1

	printf "$(((${API_VER} / 100) % 100)).$((($API_VER) % 100))\n"

	;;
ldflags)
	findlib

	[ "${LIBLUA_VER:-0}" -gt 0 ] || exit 1

	if [ "${#LIBLUA_DIR}" -gt 0 ]; then
		printf -- "-L%s\n" "${LIBLUA_DIR}"
	fi

	;;
libs)
	findlib

	[ "${LIBLUA_VER:-0}" -gt 0 ] || exit 1

	printf -- "-l%s\n" "${LIBLUA_LIB}"

	;;
libv*)
	findlib

	[ "${LIBLUA_VER:-0}" -gt 0 ] || exit 1

	printf "$(((${LIBLUA_VER} / 100) % 100)).$((($LIBLUA_VER) % 100))\n"

	;;
luac)
	shift

	if [ $# -gt 0 ]; then
		append GLOB $*
	fi

	findluac || exit 1

	printf -- "${LUAC_PATH}\n"

	;;
lua)
	shift

	if [ $# -gt 0 ]; then
		append GLOB $*
	fi

	findlua || exit 1

	printf -- "${LUA_PATH}\n"

	;;
ldir|cdir)
	#
	# ldir and cdir were deprecated on 2014-12-18. On 2016-03-25 they
	# were revived because their names are more intuitive than
	# package.path and package.cpath. For now try to support the
	# semantics of both by assuming interpreter glob patterns only match
	# file names, while preferred install directory string.match
	# expressions have directory components.
	#
	if true; then
		MODE="${1}"

		# move command to end; rotates to ${1} after loop
		set -- "$@" "${1}"
		shift

		cdir_I=0
		cdir_N="$(($# - 1))"
		while [ "${cdir_I}" -lt "${cdir_N}" ]; do
			if [ "${1#*/}" = "${1}" ]; then
				append GLOB "${1}"
				warn "%s: passing glob patterns to %s is deprecated" "${1}" "${MODE}"
			else
				set -- "$@" "${1}"
			fi
			shift
			cdir_I=$((${cdir_I} + 1))
		done
	fi

	findlua || exit 1

	findinstalldir "$@" || exit 1

	;;
package.path|package.cpath)
	findlua || exit 1

	findinstalldir "$@" || exit 1

	;;
ccname)
	ccname

	;;
evalmacro)
	shift

	evalmacro  $*
	;;
testsym)
	shift

	if testsym $*; then
		printf "found\n"
		exit 0
	else
		printf "not found\n"
		exit 1
	fi
	;;
*)
	if [ -n "${1:-}" ]; then
		warn "%s: unknown command" "${1}"
	else
		warn "no command specified"
	fi

	exit 1
	;;
esac

exit 0