added directory mapping cache. if the same directory is being hit

as last run, we don't need to rebuild the map.  will likely break if
you are running more than one at a time, in that the cache will be
ineffective.  also, if the directory contents change, this will also break.

Tools/unix/casefn.sh

@@ -4,15 +4,19 @@
 #
 # we don't handle files with embedded spaces, a horrible idea anyway
 #
-search=/tmp/cn.search.$$
-all=/tmp/cn.all.$$
-in=/tmp/cn.in.$$
+# this is a bit slow with lots of files, so there's a cache of the join file
+#
+pid=.$$
+search=/tmp/casefn.search$pid
+join=/tmp/casefn.join$pid
+in=/tmp/casefn.in$pid
+cache=/tmp/casefn.cache
 
 function cleanup {
-	rm -f $all $search $in
+	rm -f $join $search $in
 }
 
-#trap cleanup EXIT
+trap cleanup EXIT
 cleanup
 
 if [ $# -lt 1 ] ; then
@@ -21,35 +25,45 @@ fi
 
 #
 # normalize to lower case all input file names
+# while building an enumeration of all distinct directories
 #
-
 for infn in $* ; do
 	dirn=$(dirname $infn)
 	df=
-	for dl in ${dirs[@]} ; do
+	for dl in $dirs ; do
 		if [ $dl == $dirn ] ; then
 			df=$dl
 			break;
 		fi
 	done
 	if [ -z $df ] ; then
-		dirs+=( $dirn )
+		dirs="$dirs $dirn"
 	fi
 	echo -n $dirn/ >> $in
 	basename $infn | tr '[A-Z]' '[a-z]' >> $in
 done
-
 sort -u $in > $search
-#echo search: 
-#cat $search
 
 here=$(pwd)
 
+#
+# if our cached join list matches our directory list, use it
+#
+if [ -f $cache ] ; then
+	cachedirs="$(head -1 $cache)"
+	if [ "$dirs" = "$cachedirs" ] ; then
+		tail -n +2 $cache > $join
+	else
+		rm -f $cache
+	fi
+fi
+
 #
 # build join list of file names and lower case forms
 #
-rm -f $in
-for dn in ${dirs[@]} ; do
+if [ ! -f $join ] ; then
+	rm -f $in
+	for dn in ${dirs[@]} ; do
 		cd $here
 		cd $dn
 		for i in * ; do
@@ -59,10 +73,13 @@ for dn in ${dirs[@]} ; do
 			fi
 			echo $dn/$(echo "$i" | tr '[A-Z]' '[a-z]')",$dn/$i" >> $in
 		done
-done
-sort -t, -k 1,1 $in > $all
+	done
+	sort -t, -k 1,1 $in > $join
+	echo "$dirs" > $cache
+	cat $join >> $cache
+fi
 
-join -t, -o 1.2 $all $search | sort -u > $in
+join -t, -o 1.2 $join $search | sort -u > $in
 if [ $(wc -l < $in) -gt 0 ] ; then
 	cat $in
 	exit 0