Warn as well if no directory name for cachedir provided

cachedir is used to determine where cache files are stored.
the empty directory will ends up to put them under the top of
directory of XDG_CACHE_HOME. that messes it up and must be avoided.

As a note, if you want to read/write something from the top of
XDG_DATA_HOME (dir) and/or XDG_CACHE_HOME (cachedir),
put "." instead of the empty.

https://gitlab.freedesktop.org/fontconfig/fontconfig/issues/180

src/fcxml.c

@@ -2301,6 +2301,11 @@ FcParseCacheDir (FcConfigParse *parse)
 	data = prefix;
 	goto bail;
     }
+    if (data[0] == 0)
+    {
+	FcConfigMessage (parse, FcSevereWarning, "empty cache directory name ignored");
+	return;
+    }
     if (prefix)
     {
 	size_t plen = strlen ((const char *)prefix);

test/Makefile.am

@@ -135,8 +135,22 @@ check_PROGRAMS += test-bz1744377
 test_bz1744377_LDADD = $(top_builddir)/src/libfontconfig.la
 TESTS += test-bz1744377
 
+check_PROGRAMS += test-issue180
+test_issue180_LDADD = $(top_builddir)/src/libfontconfig.la
+TESTS += test-issue180
+
 EXTRA_DIST=run-test.sh run-test-conf.sh $(LOG_COMPILER) $(TESTDATA) out.expected-long-family-names out.expected-no-long-family-names
 
-CLEANFILES=out out1 out2 fonts.conf out.expected
+CLEANFILES =		\
+	fonts.conf	\
+	out		\
+	out1		\
+	out2		\
+	out.expected	\
+	run*.log	\
+	run*.trs	\
+	test*.log	\
+	test*.trs	\
+	$(NULL)
 
 -include $(top_srcdir)/git.mk

test/run-test.sh

@@ -82,7 +82,7 @@ export FONTCONFIG_FILE
 dotest "Basic check"
 prep
 cp $FONT1 $FONT2 $FONTDIR
-if [ -n ${SOURCE_DATE_EPOCH:-} ]; then
+if [ -n ${SOURCE_DATE_EPOCH:-} ] && [ ${#SOURCE_DATE_EPOCH} -gt 0 ]; then
     touch -m -t "`date -d \"@${SOURCE_DATE_EPOCH}\" +%y%m%d%H%M.%S`" $FONTDIR
 fi
 check
@@ -90,7 +90,7 @@ check
 dotest "With a subdir"
 prep
 cp $FONT1 $FONT2 $FONTDIR
-if [ -n ${SOURCE_DATE_EPOCH:-} ]; then
+if [ -n ${SOURCE_DATE_EPOCH:-} ] && [ ${#SOURCE_DATE_EPOCH} -gt 0 ]; then
     touch -m -t "`date -d \"@${SOURCE_DATE_EPOCH}\" +%y%m%d%H%M.%S`" $FONTDIR
 fi
 $FCCACHE $FONTDIR
@@ -100,7 +100,7 @@ dotest "Subdir with a cache file"
 prep
 mkdir $FONTDIR/a
 cp $FONT1 $FONT2 $FONTDIR/a
-if [ -n ${SOURCE_DATE_EPOCH:-} ]; then
+if [ -n ${SOURCE_DATE_EPOCH:-} ] && [ ${#SOURCE_DATE_EPOCH} -gt 0 ]; then
     touch -m -t "`date -d \"@${SOURCE_DATE_EPOCH}\" +%y%m%d%H%M.%S`" $FONTDIR/a
 fi
 $FCCACHE $FONTDIR/a
@@ -113,11 +113,11 @@ mkdir $FONTDIR/a/a
 mkdir $FONTDIR/b
 mkdir $FONTDIR/b/a
 cp $FONT1 $FONTDIR/a
-if [ -n ${SOURCE_DATE_EPOCH:-} ]; then
+if [ -n ${SOURCE_DATE_EPOCH:-} ] && [ ${#SOURCE_DATE_EPOCH} -gt 0 ]; then
     touch -m -t "`date -d \"@${SOURCE_DATE_EPOCH}\" +%y%m%d%H%M.%S`" $FONTDIR/a
 fi
 cp $FONT2 $FONTDIR/b/a
-if [ -n ${SOURCE_DATE_EPOCH:-} ]; then
+if [ -n ${SOURCE_DATE_EPOCH:-} ] && [ ${#SOURCE_DATE_EPOCH} -gt 0 ]; then
     touch -m -t "`date -d \"@${SOURCE_DATE_EPOCH}\" +%y%m%d%H%M.%S`" $FONTDIR/b/a
 fi
 check
@@ -156,7 +156,7 @@ if [ x"$BWRAP" != "x" -a "x$EXEEXT" = "x" ]; then
 dotest "Basic functionality with the bind-mounted cache dir"
 prep
 cp $FONT1 $FONT2 $FONTDIR
-if [ -n ${SOURCE_DATE_EPOCH:-} ]; then
+if [ -n ${SOURCE_DATE_EPOCH:-} ] && [ ${#SOURCE_DATE_EPOCH} -gt 0 ]; then
     touch -m -t "`date -d \"@${SOURCE_DATE_EPOCH}\" +%y%m%d%H%M.%S`" $FONTDIR
 fi
 $FCCACHE $FONTDIR
@@ -198,7 +198,7 @@ rm -rf $TESTTMPDIR out1 out2 xxx flist1 flist2 bind-fonts.conf
 dotest "Different directory content between host and sandbox"
 prep
 cp $FONT1 $FONTDIR
-if [ -n ${SOURCE_DATE_EPOCH:-} ]; then
+if [ -n ${SOURCE_DATE_EPOCH:-} ] && [ ${#SOURCE_DATE_EPOCH} -gt 0 ]; then
     touch -m -t "`date -d \"@${SOURCE_DATE_EPOCH}\" +%y%m%d%H%M.%S`" $FONTDIR
 fi
 $FCCACHE $FONTDIR
@@ -208,7 +208,7 @@ stat -c '%n %s %y %z' `cat out1` > stat1
 TESTTMPDIR=`mktemp -d /tmp/fontconfig.XXXXXXXX`
 TESTTMP2DIR=`mktemp -d /tmp/fontconfig.XXXXXXXX`
 cp $FONT2 $TESTTMP2DIR
-if [ -n ${SOURCE_DATE_EPOCH:-} ]; then
+if [ -n ${SOURCE_DATE_EPOCH:-} ] && [ ${#SOURCE_DATE_EPOCH} -gt 0 ]; then
     touch -m -t "`date -d \"@${SOURCE_DATE_EPOCH}\" +%y%m%d%H%M.%S`" $TESTTMP2DIR
 fi
 sed "s!@FONTDIR@!$TESTTMPDIR/fonts</dir><dir salt="'"'"salt-to-make-different"'"'">$FONTDIR!
@@ -251,7 +251,7 @@ dotest "Check consistency of MD5 in cache name"
 prep
 mkdir -p $FONTDIR/sub
 cp $FONT1 $FONTDIR/sub
-if [ -n ${SOURCE_DATE_EPOCH:-} ]; then
+if [ -n ${SOURCE_DATE_EPOCH:-} ] && [ ${#SOURCE_DATE_EPOCH} -gt 0 ]; then
     touch -m -t "`date -d \"@${SOURCE_DATE_EPOCH}\" +%y%m%d%H%M.%S`" $FONTDIR/sub
 fi
 $FCCACHE $FONTDIR
@@ -278,7 +278,7 @@ rm -rf $TESTTMPDIR out1 out2 bind-fonts.conf
 dotest "Fallback to uuid"
 prep
 cp $FONT1 $FONTDIR
-if [ -n ${SOURCE_DATE_EPOCH:-} ]; then
+if [ -n ${SOURCE_DATE_EPOCH:-} ] && [ ${#SOURCE_DATE_EPOCH} -gt 0 ]; then
     touch -m -t "`date -d \"@${SOURCE_DATE_EPOCH}\" +%y%m%d%H%M.%S`" $FONTDIR
 fi
 touch -d @`stat -c %Y $FONTDIR` $FONTDIR
@@ -321,7 +321,7 @@ mkdir -p $MyPWD/sysroot/$FONTDIR
 mkdir -p $MyPWD/sysroot/$CACHEDIR
 mkdir -p $MyPWD/sysroot/$MyPWD
 cp $FONT1 $MyPWD/sysroot/$FONTDIR
-if [ -n ${SOURCE_DATE_EPOCH:-} ]; then
+if [ -n ${SOURCE_DATE_EPOCH:-} ] && [ ${#SOURCE_DATE_EPOCH} -gt 0 ]; then
     touch -m -t "`date -d \"@${SOURCE_DATE_EPOCH}\" +%y%m%d%H%M.%S`" $MyPWD/sysroot/$FONTDIR
 fi
 cp $MyPWD/fonts.conf $MyPWD/sysroot/$MyPWD/fonts.conf

test/test-issue180.c

@@ -0,0 +1,73 @@
+/*
+ * fontconfig/test/test-issue180.c
+ *
+ * Copyright © 2000 Keith Packard
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation, and that the name of the author(s) not be used in
+ * advertising or publicity pertaining to distribution of the software without
+ * specific, written prior permission.  The authors make no
+ * representations about the suitability of this software for any purpose.  It
+ * is provided "as is" without express or implied warranty.
+ *
+ * THE AUTHOR(S) DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <fontconfig/fontconfig.h>
+
+int
+main (void)
+{
+    const FcChar8 *doc = ""
+	"<fontconfig>\n"
+	"  <cachedir></cachedir>\n"
+	"</fontconfig>\n"
+	"";
+    const FcChar8 *doc2 = ""
+	"<fontconfig>\n"
+	"  <cachedir prefix=\"xdg\"></cachedir>\n"
+	"</fontconfig>\n"
+	"";
+    FcConfig *cfg = FcConfigCreate ();
+    FcStrList *l;
+    FcChar8 *p;
+
+    if (!FcConfigParseAndLoadFromMemory (cfg, doc, FcTrue))
+    {
+	fprintf (stderr, "Unable to load a config from memory.\n");
+	return 1;
+    }
+    l = FcConfigGetCacheDirs (cfg);
+    if ((p = FcStrListNext (l)) != NULL)
+    {
+	fprintf (stderr, "There was one or more cachedirs\n");
+	return 1;
+    }
+    FcConfigDestroy (cfg);
+    cfg = FcConfigCreate ();
+    if (!FcConfigParseAndLoadFromMemory (cfg, doc2, FcTrue))
+    {
+	fprintf (stderr, "Unable to load a config from memory (with prefix).\n");
+	return 1;
+    }
+    l = FcConfigGetCacheDirs (cfg);
+    if ((p = FcStrListNext (l)) != NULL)
+    {
+	fprintf (stderr, "There was one or more cachedirs (with prefix)\n");
+	return 1;
+    }
+
+    FcConfigDestroy (cfg);
+
+    return 0;
+}