From 8b4fe70a2a3767249abf5abfb8e0db2a9e5749f8 Mon Sep 17 00:00:00 2001
From: Michael Orlitzky <michael@orlitzky.com>
Date: Sat, 7 Jun 2025 10:14:00 -0400
Subject: [PATCH] src/svgtiny.c: add impotent svgtiny_preparse_styles()
 function

We declare and add the svgtiny_preparse_styles() function that will be
used to make a first pass through the SVG document and parse all of
the <style> elements. At the moment it is only half implemented:
once we find a <style> element, we do nothing with it. A separate
function will be used to parse a <style> once we have it.
---
 src/svgtiny.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 67 insertions(+), 1 deletion(-)

diff --git a/src/svgtiny.c b/src/svgtiny.c
index a3080ea..4c126ed 100644
--- a/src/svgtiny.c
+++ b/src/svgtiny.c
@@ -1069,6 +1069,69 @@ parse_element(dom_element *element, struct svgtiny_parse_state *state)
 	return code;
 }
 
+/**
+ * Parse all <style> elements within a root <svg> element. This
+ * should be called before svgtiny_parse_svg() because that function
+ * makes a single pass through the document and we'd like all style
+ * information to be available during that pass. Specifically, we'd
+ * like a <style> sheet at the end of the document to affect the
+ * rendering of elements at its beginning.
+ *
+ * The element-parsing inner loop here is essentially the same as
+ * that within svgtiny_parse_svg().
+ */
+static svgtiny_code svgtiny_preparse_styles(dom_element *svg,
+		struct svgtiny_parse_state state)
+{
+	dom_element *child;
+	dom_exception exc;
+
+	exc = dom_node_get_first_child(svg, (dom_node **) (void *) &child);
+	if (exc != DOM_NO_ERR) {
+		return svgtiny_LIBDOM_ERROR;
+	}
+	while (child != NULL) {
+		dom_element *next;
+		dom_node_type nodetype;
+		svgtiny_code code = svgtiny_OK;
+
+		exc = dom_node_get_node_type(child, &nodetype);
+		if (exc != DOM_NO_ERR) {
+			dom_node_unref(child);
+			return svgtiny_LIBDOM_ERROR;
+		}
+		if (nodetype == DOM_ELEMENT_NODE) {
+			dom_string *nodename;
+			exc = dom_node_get_node_name(child, &nodename);
+			if (exc != DOM_NO_ERR) {
+				dom_node_unref(child);
+				return svgtiny_LIBDOM_ERROR;
+			}
+
+			if (dom_string_caseless_isequal(state.interned_style,
+							nodename)) {
+				/* We have a <style> element, parse it */
+			}
+
+
+			dom_string_unref(nodename);
+		}
+		if (code != svgtiny_OK) {
+			dom_node_unref(child);
+			return code;
+		}
+		exc = dom_node_get_next_sibling(child,
+						(dom_node **) (void *) &next);
+		dom_node_unref(child);
+		if (exc != DOM_NO_ERR) {
+			return svgtiny_LIBDOM_ERROR;
+		}
+		child = next;
+	}
+
+	return svgtiny_OK;
+}
+
 
 static svgtiny_code
 initialise_parse_state(struct svgtiny_parse_state *state,
@@ -1341,7 +1404,10 @@ svgtiny_code svgtiny_parse(struct svgtiny_diagram *diagram,
 						      viewport_width,
 						      viewport_height);
 			if (code == svgtiny_OK) {
-				code = svgtiny_parse_svg(svg, state);
+				code = svgtiny_preparse_styles(svg, state);
+				if (code == svgtiny_OK) {
+					code = svgtiny_parse_svg(svg, state);
+				}
 			}
 
 			finalise_parse_state(&state);
-- 
2.49.0