Remove ownerNode and ownerRule fields from stylesheet objects.

These prevent stylesheets being used in multiple contexts simultaneously.
Their values can be inferred from the context in which the stylesheet is used.

Replace use of ownerRule to backtrack in style selection with a (fixed-size)
stack of rules to process. This prevents crashes when a sheet that was 
previously imported somewhere is reused as a top-level sheet.

svn path=/trunk/libcss/; revision=10581

3 files changed, 11 insertions, 8 deletions

diff --git a/src/select/select.c b/src/select/select.c
index b2820c8..411081e 100644
--- a/src/select/select.c
+++ b/src/select/select.c
@@ -496,6 +496,9 @@ css_error select_from_sheet(css_select_ctx *ctx, const css_stylesheet *sheet,
 {
 	const css_stylesheet *s = sheet;
 	const css_rule *rule = s->rule_list;
+	uint32_t sp = 0;
+#define IMPORT_STACK_SIZE 256
+	const css_rule *import_stack[IMPORT_STACK_SIZE];
 
 	do {
 		/* Find first non-charset rule, if we're at the list head */
@@ -514,6 +517,10 @@ css_error select_from_sheet(css_select_ctx *ctx, const css_stylesheet *sheet,
 			if (import->sheet != NULL &&
 					(import->media & state->media) != 0) {
 				/* It's applicable, so process it */
+				assert(sp < IMPORT_STACK_SIZE - 1);
+
+				import_stack[sp++] = rule;
+
 				s = import->sheet;
 				rule = s->rule_list;
 			} else {
@@ -537,9 +544,10 @@ css_error select_from_sheet(css_select_ctx *ctx, const css_stylesheet *sheet,
 				return error;
 
 			/* Find next sheet to process */
-			if (s->ownerRule != NULL) {
-				rule = s->ownerRule->next;
-				s = s->ownerRule->parent;
+			if (sp > 0) {
+				sp--;
+				rule = import_stack[sp]->next;
+				s = import_stack[sp]->parent;
 			} else {
 				s = NULL;
 			}
diff --git a/src/stylesheet.c b/src/stylesheet.c
index 20cc91f..eed4735 100644
--- a/src/stylesheet.c
+++ b/src/stylesheet.c
@@ -361,8 +361,6 @@ css_error css_stylesheet_register_import(css_stylesheet *parent,
 		if (r->type == CSS_RULE_IMPORT && i->sheet == NULL) {
 			i->sheet = import;
 
-			import->ownerRule = r;
-
 			return CSS_OK;
 		}
 	}
diff --git a/src/stylesheet.h b/src/stylesheet.h
index b708257..2c6caac 100644
--- a/src/stylesheet.h
+++ b/src/stylesheet.h
@@ -157,9 +157,6 @@ struct css_stylesheet {
 	char *url;				/**< URL of this sheet */
 	char *title;				/**< Title of this sheet */
 
-	void *ownerNode;			/**< Owning node in document */
-	css_rule *ownerRule;			/**< Owning rule in parent */
-
 	css_language_level level;		/**< Language level of sheet */
 	css_parser *parser;			/**< Core parser for sheet */
 	void *parser_frontend;			/**< Frontend parser */