# $NetBSD: find-prefix.mk,v 1.6 2008/02/10 10:12:13 rillig Exp $
#
# This is a "subroutine" that can be included to find the installation
# prefix of an installed package.
#
# Parameters:
#
# FIND_PREFIX
#	A list of <VARNAME>=<pattern> pairs, where
#
#	* <pattern> is a package wildcard pattern (see pkg_info(8)),
#	* <VARNAME> is the variable that will be set to the
#	  installation prefix for the package.
#
# Returns:
#
# <VARNAME>
#	The prefix of the corresponding package, or ${LOCALBASE}
#	if the package is not installed.
#
# Example:
#
# FIND_PREFIX:=	M4DIR=gm4
# .include "../../mk/find-prefix.mk"
# # ${M4DIR} now contains the installation prefix for the "gm4" package.
#

.for i in ${FIND_PREFIX}
.  for varname in ${i:C/=.*$//}
.    for pattern in ${i:C/^[^=]*=//}
.      if !defined(${varname})

# XXX: Is this *_DEFAULT variable really necessary? The default value
# can be easily embedded in the shell code. What if VARNAME is set to
# PKG_APACHE, for example?
#
${varname}_DEFAULT?=	${LOCALBASE}
_${varname}_cmd=		\
	${PKG_INFO} -qp ${pattern:Q} 2>/dev/null |			\
	{ read cmd arg;							\
	  case "$$arg" in						\
	  "")	${ECHO} ${${varname}_DEFAULT:Q} ;;			\
	  *)	${ECHO} "$$arg" ;;					\
	  esac; }
${varname}=		${_${varname}_cmd:sh}
.      endif
MAKEVARS+=	${varname}
.    endfor
.  endfor
.endfor