On Tuesday 14 April 2015 09:31:25 Alex Bligh wrote:
> On 13 Apr 2015, at 22:43, Christian Schoenebeck <schoeneb...@crudebyte.com>
wrote:
> > I just encountered an issue with stand-alone less-than characters if the
> > document is parsed by libxml2's HTML parser module. Consider you have a
> > text
> >
> > in your HTML document like:
> > a < b
> >
> > The less-than sign in this case is interpreted by the HTML parser module
> > as tag start, causing subsequent text (in this case "< b") to be
> > dropped.
>
> Isn't that correct? Shouldn't your document have
>
> a < b
If it was a well-formed HTML document, then yes. But as said, in reality there
are a load of HTML documents which contain text with raw less-than characters,
supported by the fact that all major HTML browsers can handle it. libxml's
HTML parser is yet an exception here.
Attached you find a patch, suggesting a fix for this issue.
Best regards,
Christian Schoenebeck
diff -u libxml2-2.9.1+dfsg1.orig/HTMLparser.c libxml2-2.9.1+dfsg1/HTMLparser.c
--- libxml2-2.9.1+dfsg1.orig/HTMLparser.c 2015-04-14 13:05:01.000000000 +0200
+++ libxml2-2.9.1+dfsg1/HTMLparser.c 2015-04-14 16:25:19.999633601 +0200
@@ -2948,8 +2948,10 @@
/**
- * htmlParseCharData:
+ * htmlParseCharDataInternal:
* @ctxt: an HTML parser context
+ * @prep: optional character to be prepended to text, 0 if no character
+ * shall be prepended
*
* parse a CharData section.
* if we are within a CDATA section ']]>' marks an end of section.
@@ -2958,12 +2960,15 @@
*/
static void
-htmlParseCharData(htmlParserCtxtPtr ctxt) {
- xmlChar buf[HTML_PARSER_BIG_BUFFER_SIZE + 5];
+htmlParseCharDataInternal(htmlParserCtxtPtr ctxt, char prep) {
+ xmlChar buf[HTML_PARSER_BIG_BUFFER_SIZE + 6];
int nbchar = 0;
int cur, l;
int chunk = 0;
+ if (prep)
+ buf[nbchar++] = prep;
+
SHRINK;
cur = CUR_CHAR(l);
while (((cur != '<') || (ctxt->token == '<')) &&
@@ -3043,6 +3048,21 @@
}
/**
+ * htmlParseCharData:
+ * @ctxt: an HTML parser context
+ *
+ * parse a CharData section.
+ * if we are within a CDATA section ']]>' marks an end of section.
+ *
+ * [14] CharData ::= [^<&]* - ([^<&]* ']]>' [^<&]*)
+ */
+
+static void
+htmlParseCharData(htmlParserCtxtPtr ctxt) {
+ htmlParseCharDataInternal(ctxt, 0);
+}
+
+/**
* htmlParseExternalID:
* @ctxt: an HTML parser context
* @publicID: a xmlChar** receiving PubidLiteral
@@ -4157,14 +4177,22 @@
}
/*
- * Third case : a sub-element.
+ * Third case : (unescaped) stand-alone less-than character.
+ */
+ else if ((CUR == '<') && (IS_BLANK_CH(NXT(1)) || (NXT(1) == '='))) {
+ NEXT;
+ htmlParseCharDataInternal(ctxt, '<');
+ }
+
+ /*
+ * Fourth case : a sub-element.
*/
else if (CUR == '<') {
htmlParseElement(ctxt);
}
/*
- * Fourth case : a reference. If if has not been resolved,
+ * Fifth case : a reference. If if has not been resolved,
* parsing returns it's Name, create the node
*/
else if (CUR == '&') {
@@ -4172,7 +4200,7 @@
}
/*
- * Fifth case : end of the resource
+ * Sixth case : end of the resource
*/
else if (CUR == 0) {
htmlAutoCloseOnEnd(ctxt);
@@ -4567,7 +4595,15 @@
}
/*
- * Third case : a sub-element.
+ * Third case : (unescaped) stand-alone less-than character.
+ */
+ else if ((CUR == '<') && (IS_BLANK_CH(NXT(1)) || (NXT(1) == '='))) {
+ NEXT;
+ htmlParseCharDataInternal(ctxt, '<');
+ }
+
+ /*
+ * Fourth case : a sub-element.
*/
else if (CUR == '<') {
htmlParseElementInternal(ctxt);
@@ -4578,7 +4614,7 @@
}
/*
- * Fourth case : a reference. If if has not been resolved,
+ * Fifth case : a reference. If if has not been resolved,
* parsing returns it's Name, create the node
*/
else if (CUR == '&') {
@@ -4586,7 +4622,7 @@
}
/*
- * Fifth case : end of the resource
+ * Sixth case : end of the resource
*/
else if (CUR == 0) {
htmlAutoCloseOnEnd(ctxt);
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