From: Michael Orlitzky <michael@orlitzky.com>
Date: Fri, 13 Oct 2023 01:40:34 +0000 (-0400)
Subject: src/svgtiny_css.c: implement node_has_attribute_includes() select handler
X-Git-Url: https://gitweb.michael.orlitzky.com/?a=commitdiff_plain;ds=sidebyside;h=f85c9deca18012fb216ed81f613c6834d3fd2bb2;p=libsvgtiny.git

src/svgtiny_css.c: implement node_has_attribute_includes() select handler
---

diff --git a/src/svgtiny_css.c b/src/svgtiny_css.c
index 5dbb83e..3b03d91 100644
--- a/src/svgtiny_css.c
+++ b/src/svgtiny_css.c
@@ -30,6 +30,9 @@ static css_error node_has_attribute_equal(void *pw, void *node,
 static css_error node_has_attribute_dashmatch(void *pw, void *node,
 		const css_qname *qname, lwc_string *value,
 		bool *match);
+static css_error node_has_attribute_includes(void *pw, void *node,
+		const css_qname *qname, lwc_string *word,
+		bool *match);
 
 
 /**
@@ -818,3 +821,93 @@ css_error node_has_attribute_dashmatch(void *pw, void *node,
 
 	return CSS_OK;
 }
+
+
+/**
+ * Test the given node for an attribute whose value is a
+ * space-separated list of words, one of which is the given word
+ *
+ * This will return true (via the "match" pointer) if the libdom node
+ * has an attribute with the given name and whose value when
+ * considered as a space-separated list of words contains the given
+ * word. The comparison is case-sensitive. This corresponds to
+ * [attr~=value] in CSS.
+ *
+ * \param pw       Pointer to the current SVG parser state
+ * \param node     Libdom SVG node to test
+ * \param qname    Attribute name to check for
+ * \param word     Value word to check for
+ * \param match    Pointer to the test result
+ *
+ * \return Returns CSS_OK if successful and CSS_NOMEM if we cannot
+ *         intern the attribute name (which usually indicates memory
+ *         exhaustion)
+ */
+css_error node_has_attribute_includes(void *pw, void *node,
+		const css_qname *qname, lwc_string *word,
+		bool *match)
+{
+	UNUSED(pw);
+
+	dom_string *name;
+	dom_string *attr_val;
+	dom_exception err;
+	size_t wordlen; /* length of "word" */
+
+	/* pointers used to parse a space-separated list of words */
+	const char *p;
+	const char *start;
+	const char *end;
+
+	*match = false; /* default to no match */
+
+	wordlen = lwc_string_length(word);
+	if (wordlen == 0) {
+		/* In this case, the spec says that "if 'val' is the
+		 * empty string, it will never represent anything." */
+		return CSS_OK;
+	}
+
+	/* Intern the attribute name as a dom_string so we can
+	 * use dom_element_get_attribute() */
+	err = dom_string_create_interned(
+		(const uint8_t *) lwc_string_data(qname->name),
+		lwc_string_length(qname->name),
+		&name);
+	if (err != DOM_NO_ERR) {
+		return CSS_NOMEM;
+	}
+
+	err = dom_element_get_attribute((dom_node *)node, name, &attr_val);
+	if ((err != DOM_NO_ERR) || (attr_val == NULL)) {
+		/* There was an error getting the attribute's value or
+		 * the attribute doesn't exist. So, no match? */
+		dom_string_unref(name);
+		return CSS_OK;
+	}
+
+	/* Parse the list comparing each word against "word" */
+	start = dom_string_data(attr_val);
+	end = start + dom_string_byte_length(attr_val);
+	dom_string_unref(attr_val);
+
+	for (p = start; p <= end; p++) {
+		/* Move forward until we find the end of the first word */
+		if (*p == ' ' || *p == '\0') {
+			/* If the length of that word is the length of the
+			 * word we're looking for, do the comparison. */
+			if ((size_t) (p - start) == wordlen &&
+				strncasecmp(start,
+					lwc_string_data(word),
+					wordlen) == 0) {
+				*match = true;
+				break;
+			}
+			/* No match? Set "start" to the beginning of
+			 * the next word and loop. */
+			start = p + 1;
+		}
+	}
+
+	return CSS_OK;
+}