guix/gnu/packages/patches/libxml2-xpath0-Add-option-xpath0.patch

This patch adds an "--xpath0" option to xmllint so that NUL characters
can be used as separators.

See <https://gitlab.gnome.org/GNOME/libxml2/-/issues/227>.

diff --git a/doc/xmllint.xml b/doc/xmllint.xml
--- a/doc/xmllint.xml
+++ b/doc/xmllint.xml
@@ -70,6 +70,7 @@
 			<arg choice="plain"><option>--debug</option></arg>
 			<arg choice="plain"><option>--shell</option></arg>
 			<arg choice="plain"><option>--xpath "<replaceable class="option">XPath_expression</replaceable>"</option></arg>
+			<arg choice="plain"><option>--xpath0 "<replaceable class="option">XPath_expression</replaceable>"</option></arg>
 			<arg choice="plain"><option>--debugent</option></arg>
 			<arg choice="plain"><option>--copy</option></arg>
 			<arg choice="plain"><option>--recover</option></arg>
@@ -537,6 +538,21 @@
 			node set is serialized in full in the output. In case
 			of an empty node set the "XPath set is empty" result
 			will be shown and an error exit code will be returned.
+			Results are separated by the newline character.
+		</para>
+	</listitem>
+		</varlistentry>
+
+		<varlistentry>
+	<term><option>--xpath0 "<replaceable class="option">XPath_expression</replaceable>"</option></term>
+	<listitem>
+		<para>
+			Run an XPath expression given as argument and print the
+			result. In case of a nodeset result, each node in the
+			node set is serialized in full in the output. In case
+			of an empty node set the "XPath set is empty" result
+			will be shown and an error exit code will be returned.
+			Results are separated by the null character.
 		</para>
 	</listitem>
 		</varlistentry>
diff --git a/xmllint.c b/xmllint.c
--- a/xmllint.c
+++ b/xmllint.c
@@ -194,6 +194,7 @@ static int sax1 = 0;
 #endif /* LIBXML_SAX1_ENABLED */
 #ifdef LIBXML_XPATH_ENABLED
 static const char *xpathquery = NULL;
+static const char *xpathsep = "\n";
 #endif
 static int options = XML_PARSE_COMPACT | XML_PARSE_BIG_LINES;
 static int sax = 0;
@@ -2095,7 +2096,7 @@ static void doXPathDump(xmlXPathObjectPtr cur) {
             for (i = 0;i < cur->nodesetval->nodeNr;i++) {
                 node = cur->nodesetval->nodeTab[i];
                 xmlNodeDumpOutput(buf, NULL, node, 0, 0, NULL);
-                xmlOutputBufferWrite(buf, 1, "\n");
+		xmlOutputBufferWrite(buf, 1, xpathsep);
             }
             xmlOutputBufferClose(buf);
 #else
@@ -2104,27 +2105,27 @@ static void doXPathDump(xmlXPathObjectPtr cur) {
 	    break;
         }
         case XPATH_BOOLEAN:
-	    if (cur->boolval) printf("true\n");
-	    else printf("false\n");
+	    if (cur->boolval) printf("true%s", xpathsep);
+	    else printf("false%s", xpathsep);
 	    break;
         case XPATH_NUMBER:
 	    switch (xmlXPathIsInf(cur->floatval)) {
 	    case 1:
-		printf("Infinity\n");
+	        printf("Infinity%s", xpathsep);
 		break;
 	    case -1:
-		printf("-Infinity\n");
+	        printf("-Infinity%s", xpathsep);
 		break;
 	    default:
 		if (xmlXPathIsNaN(cur->floatval)) {
-		    printf("NaN\n");
+		    printf("NaN%s", xpathsep);
 		} else {
-		    printf("%0g\n", cur->floatval);
+		    printf("%0g%s", cur->floatval, xpathsep);
 		}
 	    }
 	    break;
         case XPATH_STRING:
-	    printf("%s\n", (const char *) cur->stringval);
+	    printf("%s%s", (const char *) cur->stringval, xpathsep);
 	    break;
         case XPATH_UNDEFINED:
 	    fprintf(stderr, "XPath Object is uninitialized\n");
@@ -3098,7 +3099,8 @@ static void usage(FILE *f, const char *name) {
     fprintf(f, "\t--sax: do not build a tree but work just at the SAX level\n");
     fprintf(f, "\t--oldxml10: use XML-1.0 parsing rules before the 5th edition\n");
 #ifdef LIBXML_XPATH_ENABLED
-    fprintf(f, "\t--xpath expr: evaluate the XPath expression, imply --noout\n");
+    fprintf(f, "\t--xpath expr: evaluate the XPath expression, results are separated by \\n, imply --noout\n");
+    fprintf(f, "\t--xpath0 expr: evaluate the XPath expression, results are separated by \\0, imply --noout\n");
 #endif
 
     fprintf(f, "\nLibxml project home page: http://xmlsoft.org/\n");
@@ -3480,6 +3482,13 @@ main(int argc, char **argv) {
 	    i++;
 	    noout++;
 	    xpathquery = argv[i];
+	    xpathsep = "\n";
+        } else if ((!strcmp(argv[i], "-xpath0")) ||
+                   (!strcmp(argv[i], "--xpath0"))) {
+	    i++;
+	    noout++;
+	    xpathquery = argv[i];
+	    xpathsep = "\0";
 #endif
 	} else if ((!strcmp(argv[i], "-oldxml10")) ||
 	           (!strcmp(argv[i], "--oldxml10"))) {
@@ -3712,6 +3721,11 @@ main(int argc, char **argv) {
 	    i++;
 	    continue;
 	}
+        if ((!strcmp(argv[i], "-xpath0")) ||
+	    (!strcmp(argv[i], "--xpath0"))) {
+	    i++;
+	    continue;
+	}
 #endif
 	if ((timing) && (repeat))
 	    startTimer();