Use pool allocator when parsing CSS.

Fixes memory leaks when parsing throws exceptions and saves a lot of
tiny mallocs for objects that have common life times.

6 files changed, 168 insertions, 173 deletions

diff --git a/include/mupdf/fitz/pool.h b/include/mupdf/fitz/pool.h
index 924fb804..919b08d0 100644
--- a/include/mupdf/fitz/pool.h
+++ b/include/mupdf/fitz/pool.h
@@ -21,6 +21,7 @@ struct fz_pool_node_s
 
 fz_pool *fz_new_pool(fz_context *ctx);
 void *fz_pool_alloc(fz_context *ctx, fz_pool *pool, size_t size);
+char *fz_pool_strdup(fz_context *ctx, fz_pool *pool, const char *s);
 void fz_drop_pool(fz_context *ctx, fz_pool *pool);
 
 #endif
diff --git a/include/mupdf/html.h b/include/mupdf/html.h
index 7c3eadac..f9bd4d98 100644
--- a/include/mupdf/html.h
+++ b/include/mupdf/html.h
@@ -9,6 +9,7 @@ typedef struct fz_html_s fz_html;
 typedef struct fz_html_box_s fz_html_box;
 typedef struct fz_html_flow_s fz_html_flow;
 
+typedef struct fz_css_s fz_css;
 typedef struct fz_css_rule_s fz_css_rule;
 typedef struct fz_css_match_prop_s fz_css_match_prop;
 typedef struct fz_css_match_s fz_css_match;
@@ -48,11 +49,16 @@ enum
 	CSS_URI,
 };
 
+struct fz_css_s
+{
+	fz_pool *pool;
+	fz_css_rule *rule;
+};
+
 struct fz_css_rule_s
 {
 	fz_css_selector *selector;
 	fz_css_property *declaration;
-	fz_css_property *garbage; /* for freeing inline style attributes at the end */
 	fz_css_rule *next;
 };
 
@@ -244,12 +250,13 @@ struct fz_html_flow_s
 	fz_html_flow *next;
 };
 
-fz_css_rule *fz_parse_css(fz_context *ctx, fz_css_rule *chain, const char *source, const char *file);
-fz_css_property *fz_parse_css_properties(fz_context *ctx, const char *source);
-void fz_drop_css(fz_context *ctx, fz_css_rule *rule);
+fz_css *fz_new_css(fz_context *ctx);
+void fz_parse_css(fz_context *ctx, fz_css *css, const char *source, const char *file);
+fz_css_property *fz_parse_css_properties(fz_context *ctx, fz_pool *pool, const char *source);
+void fz_drop_css(fz_context *ctx, fz_css *css);
 
-void fz_match_css(fz_context *ctx, fz_css_match *match, fz_css_rule *rule, fz_xml *node);
-void fz_match_css_at_page(fz_context *ctx, fz_css_match *match, fz_css_rule *css);
+void fz_match_css(fz_context *ctx, fz_css_match *match, fz_css *css, fz_xml *node);
+void fz_match_css_at_page(fz_context *ctx, fz_css_match *match, fz_css *css);
 
 int fz_get_css_match_display(fz_css_match *node);
 void fz_default_css_style(fz_context *ctx, fz_css_style *style);
@@ -264,7 +271,7 @@ void fz_add_html_font_face(fz_context *ctx, fz_html_font_set *set,
 fz_font *fz_load_html_font(fz_context *ctx, fz_html_font_set *set, const char *family, int is_bold, int is_italic);
 void fz_drop_html_font_set(fz_context *ctx, fz_html_font_set *htx);
 
-void fz_add_css_font_faces(fz_context *ctx, fz_html_font_set *set, fz_archive *zip, const char *base_uri, fz_css_rule *css);
+void fz_add_css_font_faces(fz_context *ctx, fz_html_font_set *set, fz_archive *zip, const char *base_uri, fz_css *css);
 
 fz_html *fz_parse_html(fz_context *ctx, fz_html_font_set *htx, fz_archive *zip, const char *base_uri, fz_buffer *buf, const char *user_css);
 void fz_layout_html(fz_context *ctx, fz_html *html, float w, float h, float em);
diff --git a/source/fitz/pool.c b/source/fitz/pool.c
index e676947f..2591c563 100644
--- a/source/fitz/pool.c
+++ b/source/fitz/pool.c
@@ -31,6 +31,14 @@ void *fz_pool_alloc(fz_context *ctx, fz_pool *pool, size_t size)
 	return ptr;
 }
 
+char *fz_pool_strdup(fz_context *ctx, fz_pool *pool, const char *s)
+{
+	size_t n = strlen(s) + 1;
+	char *p = fz_pool_alloc(ctx, pool, n);
+	memcpy(p, s, n);
+	return p;
+}
+
 void fz_drop_pool(fz_context *ctx, fz_pool *pool)
 {
 	fz_pool_node *node = pool->head;
diff --git a/source/html/css-apply.c b/source/html/css-apply.c
index d7375752..03e61a87 100644
--- a/source/html/css-apply.c
+++ b/source/html/css-apply.c
@@ -622,14 +622,14 @@ sort_properties(fz_css_match *match)
 }
 
 void
-fz_match_css(fz_context *ctx, fz_css_match *match, fz_css_rule *css, fz_xml *node)
+fz_match_css(fz_context *ctx, fz_css_match *match, fz_css *css, fz_xml *node)
 {
 	fz_css_rule *rule;
 	fz_css_selector *sel;
 	fz_css_property *prop, *head, *tail;
 	const char *s;
 
-	for (rule = css; rule; rule = rule->next)
+	for (rule = css->rule; rule; rule = rule->next)
 	{
 		sel = rule->selector;
 		while (sel)
@@ -649,16 +649,14 @@ fz_match_css(fz_context *ctx, fz_css_match *match, fz_css_rule *css, fz_xml *nod
 	{
 		fz_try(ctx)
 		{
-			head = tail = prop = fz_parse_css_properties(ctx, s);
+			head = tail = prop = fz_parse_css_properties(ctx, css->pool, s);
 			while (prop)
 			{
 				add_property(match, prop->name, prop->value, INLINE_SPECIFICITY);
 				tail = prop;
 				prop = prop->next;
 			}
-			if (tail)
-				tail->next = css->garbage;
-			css->garbage = head;
+			/* We can "leak" the property here, since it is freed along with the pool allocator. */
 		}
 		fz_catch(ctx)
 		{
@@ -670,13 +668,13 @@ fz_match_css(fz_context *ctx, fz_css_match *match, fz_css_rule *css, fz_xml *nod
 }
 
 void
-fz_match_css_at_page(fz_context *ctx, fz_css_match *match, fz_css_rule *css)
+fz_match_css_at_page(fz_context *ctx, fz_css_match *match, fz_css *css)
 {
 	fz_css_rule *rule;
 	fz_css_selector *sel;
 	fz_css_property *prop;
 
-	for (rule = css; rule; rule = rule->next)
+	for (rule = css->rule; rule; rule = rule->next)
 	{
 		sel = rule->selector;
 		while (sel)
@@ -761,12 +759,12 @@ fz_add_css_font_face(fz_context *ctx, fz_html_font_set *set, fz_archive *zip, co
 }
 
 void
-fz_add_css_font_faces(fz_context *ctx, fz_html_font_set *set, fz_archive *zip, const char *base_uri, fz_css_rule *css)
+fz_add_css_font_faces(fz_context *ctx, fz_html_font_set *set, fz_archive *zip, const char *base_uri, fz_css *css)
 {
 	fz_css_rule *rule;
 	fz_css_selector *sel;
 
-	for (rule = css; rule; rule = rule->next)
+	for (rule = css->rule; rule; rule = rule->next)
 	{
 		sel = rule->selector;
 		while (sel)
diff --git a/source/html/css-parse.c b/source/html/css-parse.c
index 7fd8571a..b5d436e8 100644
--- a/source/html/css-parse.c
+++ b/source/html/css-parse.c
@@ -3,6 +3,7 @@
 struct lexbuf
 {
 	fz_context *ctx;
+	fz_pool *pool;
 	const unsigned char *s;
 	const char *file;
 	int line;
@@ -20,20 +21,45 @@ FZ_NORETURN static void fz_css_error(struct lexbuf *buf, const char *msg)
 	fz_throw(buf->ctx, FZ_ERROR_SYNTAX, "css syntax error: %s (%s:%d)", msg, buf->file, buf->line);
 }
 
-static fz_css_rule *fz_new_css_rule(fz_context *ctx, fz_css_selector *selector, fz_css_property *declaration)
+fz_css *fz_new_css(fz_context *ctx)
 {
-	fz_css_rule *rule = fz_malloc_struct(ctx, fz_css_rule);
+	fz_pool *pool = fz_new_pool(ctx);
+	fz_css *css;
+
+	fz_try(ctx)
+	{
+		css = fz_pool_alloc(ctx, pool, sizeof *css);
+		css->pool = pool;
+		css->rule = NULL;
+	}
+	fz_catch(ctx)
+	{
+		fz_drop_pool(ctx, pool);
+		fz_rethrow(ctx);
+	}
+
+	return css;
+}
+
+void fz_drop_css(fz_context *ctx, fz_css *css)
+{
+	if (css)
+		fz_drop_pool(ctx, css->pool);
+}
+
+static fz_css_rule *fz_new_css_rule(fz_context *ctx, fz_pool *pool, fz_css_selector *selector, fz_css_property *declaration)
+{
+	fz_css_rule *rule = fz_pool_alloc(ctx, pool, sizeof *rule);
 	rule->selector = selector;
 	rule->declaration = declaration;
-	rule->garbage = NULL;
 	rule->next = NULL;
 	return rule;
 }
 
-static fz_css_selector *fz_new_css_selector(fz_context *ctx, const char *name)
+static fz_css_selector *fz_new_css_selector(fz_context *ctx, fz_pool *pool, const char *name)
 {
-	fz_css_selector *sel = fz_malloc_struct(ctx, fz_css_selector);
-	sel->name = name ? fz_strdup(ctx, name) : NULL;
+	fz_css_selector *sel = fz_pool_alloc(ctx, pool, sizeof *sel);
+	sel->name = name ? fz_pool_strdup(ctx, pool, name) : NULL;
 	sel->combine = 0;
 	sel->cond = NULL;
 	sel->left = NULL;
@@ -42,20 +68,20 @@ static fz_css_selector *fz_new_css_selector(fz_context *ctx, const char *name)
 	return sel;
 }
 
-static fz_css_condition *fz_new_css_condition(fz_context *ctx, int type, const char *key, const char *val)
+static fz_css_condition *fz_new_css_condition(fz_context *ctx, fz_pool *pool, int type, const char *key, const char *val)
 {
-	fz_css_condition *cond = fz_malloc_struct(ctx, fz_css_condition);
+	fz_css_condition *cond = fz_pool_alloc(ctx, pool, sizeof *cond);
 	cond->type = type;
-	cond->key = key ? fz_strdup(ctx, key) : NULL;
-	cond->val = val ? fz_strdup(ctx, val) : NULL;
+	cond->key = key ? fz_pool_strdup(ctx, pool, key) : NULL;
+	cond->val = val ? fz_pool_strdup(ctx, pool, val) : NULL;
 	cond->next = NULL;
 	return cond;
 }
 
-static fz_css_property *fz_new_css_property(fz_context *ctx, const char *name, fz_css_value *value, int spec)
+static fz_css_property *fz_new_css_property(fz_context *ctx, fz_pool *pool, const char *name, fz_css_value *value, int spec)
 {
-	fz_css_property *prop = fz_malloc_struct(ctx, fz_css_property);
-	prop->name = fz_strdup(ctx, name);
+	fz_css_property *prop = fz_pool_alloc(ctx, pool, sizeof *prop);
+	prop->name = fz_pool_strdup(ctx, pool, name);
 	prop->value = value;
 	prop->spec = spec;
 	prop->important = 0;
@@ -63,9 +89,9 @@ static fz_css_property *fz_new_css_property(fz_context *ctx, const char *name, f
 	return prop;
 }
 
-static fz_css_value *fz_new_css_value_x(fz_context *ctx, int type)
+static fz_css_value *fz_new_css_value_x(fz_context *ctx, fz_pool *pool, int type)
 {
-	fz_css_value *val = fz_malloc_struct(ctx, fz_css_value);
+	fz_css_value *val = fz_pool_alloc(ctx, pool, sizeof *val);
 	val->type = type;
 	val->data = NULL;
 	val->args = NULL;
@@ -73,79 +99,16 @@ static fz_css_value *fz_new_css_value_x(fz_context *ctx, int type)
 	return val;
 }
 
-static fz_css_value *fz_new_css_value(fz_context *ctx, int type, const char *data)
+static fz_css_value *fz_new_css_value(fz_context *ctx, fz_pool *pool, int type, const char *data)
 {
-	fz_css_value *val = fz_malloc_struct(ctx, fz_css_value);
+	fz_css_value *val = fz_pool_alloc(ctx, pool, sizeof *val);
 	val->type = type;
-	val->data = fz_strdup(ctx, data);
+	val->data = fz_pool_strdup(ctx, pool, data);
 	val->args = NULL;
 	val->next = NULL;
 	return val;
 }
 
-static void fz_drop_css_value(fz_context *ctx, fz_css_value *val)
-{
-	while (val)
-	{
-		fz_css_value *next = val->next;
-		fz_drop_css_value(ctx, val->args);
-		fz_free(ctx, val->data);
-		fz_free(ctx, val);
-		val = next;
-	}
-}
-
-static void fz_drop_css_condition(fz_context *ctx, fz_css_condition *cond)
-{
-	while (cond)
-	{
-		fz_css_condition *next = cond->next;
-		fz_free(ctx, cond->key);
-		fz_free(ctx, cond->val);
-		fz_free(ctx, cond);
-		cond = next;
-	}
-}
-
-static void fz_drop_css_selector(fz_context *ctx, fz_css_selector *sel)
-{
-	while (sel)
-	{
-		fz_css_selector *next = sel->next;
-		fz_free(ctx, sel->name);
-		fz_drop_css_condition(ctx, sel->cond);
-		fz_drop_css_selector(ctx, sel->left);
-		fz_drop_css_selector(ctx, sel->right);
-		fz_free(ctx, sel);
-		sel = next;
-	}
-}
-
-static void fz_drop_css_property(fz_context *ctx, fz_css_property *prop)
-{
-	while (prop)
-	{
-		fz_css_property *next = prop->next;
-		fz_free(ctx, prop->name);
-		fz_drop_css_value(ctx, prop->value);
-		fz_free(ctx, prop);
-		prop = next;
-	}
-}
-
-void fz_drop_css(fz_context *ctx, fz_css_rule *rule)
-{
-	while (rule)
-	{
-		fz_css_rule *next = rule->next;
-		fz_drop_css_selector(ctx, rule->selector);
-		fz_drop_css_property(ctx, rule->declaration);
-		fz_drop_css_property(ctx, rule->garbage);
-		fz_free(ctx, rule);
-		rule = next;
-	}
-}
-
 static void css_lex_next(struct lexbuf *buf)
 {
 	buf->c = *(buf->s++);
@@ -153,9 +116,10 @@ static void css_lex_next(struct lexbuf *buf)
 		++buf->line;
 }
 
-static void css_lex_init(fz_context *ctx, struct lexbuf *buf, const char *s, const char *file)
+static void css_lex_init(fz_context *ctx, struct lexbuf *buf, fz_pool *pool, const char *s, const char *file)
 {
 	buf->ctx = ctx;
+	buf->pool = pool;
 	buf->s = (const unsigned char *)s;
 	buf->c = 0;
 	buf->file = file;
@@ -517,14 +481,14 @@ static fz_css_value *parse_term(struct lexbuf *buf)
 			fz_css_error(buf, "expected number");
 		if (sign < 0)
 		{
-			v = fz_new_css_value_x(buf->ctx, buf->lookahead);
-			v->data = fz_malloc(buf->ctx, strlen(buf->string) + 2);
+			v = fz_new_css_value_x(buf->ctx, buf->pool, buf->lookahead);
+			v->data = fz_pool_alloc(buf->ctx, buf->pool, strlen(buf->string) + 2);
 			v->data[0] = '-';
 			strcpy(v->data + 1, buf->string);
 		}
 		else
 		{
-			v = fz_new_css_value(buf->ctx, buf->lookahead, buf->string);
+			v = fz_new_css_value(buf->ctx, buf->pool, buf->lookahead, buf->string);
 		}
 		next(buf);
 		white(buf);
@@ -533,7 +497,7 @@ static fz_css_value *parse_term(struct lexbuf *buf)
 
 	if (buf->lookahead == CSS_KEYWORD)
 	{
-		v = fz_new_css_value(buf->ctx, CSS_KEYWORD, buf->string);
+		v = fz_new_css_value(buf->ctx, buf->pool, CSS_KEYWORD, buf->string);
 		next(buf);
 		if (accept(buf, '('))
 		{
@@ -554,7 +518,7 @@ static fz_css_value *parse_term(struct lexbuf *buf)
 	case CSS_NUMBER:
 	case CSS_LENGTH:
 	case CSS_PERCENT:
-		v = fz_new_css_value(buf->ctx, buf->lookahead, buf->string);
+		v = fz_new_css_value(buf->ctx, buf->pool, buf->lookahead, buf->string);
 		next(buf);
 		white(buf);
 		return v;
@@ -575,13 +539,13 @@ static fz_css_value *parse_expr(struct lexbuf *buf)
 		if (accept(buf, ','))
 		{
 			white(buf);
-			tail = tail->next = fz_new_css_value(buf->ctx, ',', ",");
+			tail = tail->next = fz_new_css_value(buf->ctx, buf->pool, ',', ",");
 			tail = tail->next = parse_term(buf);
 		}
 		else if (accept(buf, '/'))
 		{
 			white(buf);
-			tail = tail->next = fz_new_css_value(buf->ctx, '/', "/");
+			tail = tail->next = fz_new_css_value(buf->ctx, buf->pool, '/', "/");
 			tail = tail->next = parse_term(buf);
 		}
 		else
@@ -599,7 +563,7 @@ static fz_css_property *parse_declaration(struct lexbuf *buf)
 
 	if (buf->lookahead != CSS_KEYWORD)
 		fz_css_error(buf, "expected keyword in property");
-	p = fz_new_css_property(buf->ctx, buf->string, NULL, 0);
+	p = fz_new_css_property(buf->ctx, buf->pool, buf->string, NULL, 0);
 	next(buf);
 
 	white(buf);
@@ -652,7 +616,7 @@ static char *parse_attrib_value(struct lexbuf *buf)
 
 	if (buf->lookahead == CSS_KEYWORD || buf->lookahead == CSS_STRING)
 	{
-		s = fz_strdup(buf->ctx, buf->string);
+		s = fz_pool_strdup(buf->ctx, buf->pool, buf->string);
 		next(buf);
 		white(buf);
 		return s;
@@ -670,7 +634,7 @@ static fz_css_condition *parse_condition(struct lexbuf *buf)
 		accept(buf, ':'); /* swallow css3 :: syntax and pretend it's a normal pseudo-class */
 		if (buf->lookahead != CSS_KEYWORD)
 			fz_css_error(buf, "expected keyword after ':'");
-		c = fz_new_css_condition(buf->ctx, ':', "pseudo", buf->string);
+		c = fz_new_css_condition(buf->ctx, buf->pool, ':', "pseudo", buf->string);
 		next(buf);
 		if (accept(buf, '('))
 		{
@@ -686,7 +650,7 @@ static fz_css_condition *parse_condition(struct lexbuf *buf)
 	{
 		if (buf->lookahead != CSS_KEYWORD)
 			fz_css_error(buf, "expected keyword after '.'");
-		c = fz_new_css_condition(buf->ctx, '.', "class", buf->string);
+		c = fz_new_css_condition(buf->ctx, buf->pool, '.', "class", buf->string);
 		next(buf);
 		return c;
 	}
@@ -697,7 +661,7 @@ static fz_css_condition *parse_condition(struct lexbuf *buf)
 
 		if (buf->lookahead != CSS_KEYWORD)
 			fz_css_error(buf, "expected keyword after '['");
-		c = fz_new_css_condition(buf->ctx, '[', buf->string, NULL);
+		c = fz_new_css_condition(buf->ctx, buf->pool, '[', buf->string, NULL);
 		next(buf);
 
 		white(buf);
@@ -727,7 +691,7 @@ static fz_css_condition *parse_condition(struct lexbuf *buf)
 
 	if (buf->lookahead == CSS_HASH)
 	{
-		c = fz_new_css_condition(buf->ctx, '#', "id", buf->string);
+		c = fz_new_css_condition(buf->ctx, buf->pool, '#', "id", buf->string);
 		next(buf);
 		return c;
 	}
@@ -753,14 +717,14 @@ static fz_css_selector *parse_simple_selector(struct lexbuf *buf)
 
 	if (accept(buf, '*'))
 	{
-		s = fz_new_css_selector(buf->ctx, NULL);
+		s = fz_new_css_selector(buf->ctx, buf->pool, NULL);
 		if (iscond(buf->lookahead))
 			s->cond = parse_condition_list(buf);
 		return s;
 	}
 	else if (buf->lookahead == CSS_KEYWORD)
 	{
-		s = fz_new_css_selector(buf->ctx, buf->string);
+		s = fz_new_css_selector(buf->ctx, buf->pool, buf->string);
 		next(buf);
 		if (iscond(buf->lookahead))
 			s->cond = parse_condition_list(buf);
@@ -768,7 +732,7 @@ static fz_css_selector *parse_simple_selector(struct lexbuf *buf)
 	}
 	else if (iscond(buf->lookahead))
 	{
-		s = fz_new_css_selector(buf->ctx, NULL);
+		s = fz_new_css_selector(buf->ctx, buf->pool, NULL);
 		s->cond = parse_condition_list(buf);
 		return s;
 	}
@@ -781,7 +745,7 @@ static fz_css_selector *parse_combinator(struct lexbuf *buf, int c, fz_css_selec
 	fz_css_selector *sel, *b;
 	white(buf);
 	b = parse_simple_selector(buf);
-	sel = fz_new_css_selector(buf->ctx, NULL);
+	sel = fz_new_css_selector(buf->ctx, buf->pool, NULL);
 	sel->combine = c;
 	sel->left = a;
 	sel->right = b;
@@ -856,7 +820,7 @@ static fz_css_rule *parse_ruleset(struct lexbuf *buf)
 		return NULL;
 	}
 
-	return fz_new_css_rule(buf->ctx, s, p);
+	return fz_new_css_rule(buf->ctx, buf->pool, s, p);
 }
 
 static fz_css_rule *parse_at_page(struct lexbuf *buf)
@@ -875,8 +839,8 @@ static fz_css_rule *parse_at_page(struct lexbuf *buf)
 	expect(buf, '}');
 	white(buf);
 
-	s = fz_new_css_selector(buf->ctx, "@page");
-	return fz_new_css_rule(buf->ctx, s, p);
+	s = fz_new_css_selector(buf->ctx, buf->pool, "@page");
+	return fz_new_css_rule(buf->ctx, buf->pool, s, p);
 }
 
 static fz_css_rule *parse_at_font_face(struct lexbuf *buf)
@@ -890,8 +854,8 @@ static fz_css_rule *parse_at_font_face(struct lexbuf *buf)
 	expect(buf, '}');
 	white(buf);
 
-	s = fz_new_css_selector(buf->ctx, "@font-face");
-	return fz_new_css_rule(buf->ctx, s, p);
+	s = fz_new_css_selector(buf->ctx, buf->pool, "@font-face");
+	return fz_new_css_rule(buf->ctx, buf->pool, s, p);
 }
 
 static void parse_at_rule(struct lexbuf *buf)
@@ -979,18 +943,18 @@ static fz_css_rule *parse_stylesheet(struct lexbuf *buf, fz_css_rule *chain)
 	return chain ? chain : tail;
 }
 
-fz_css_property *fz_parse_css_properties(fz_context *ctx, const char *source)
+fz_css_property *fz_parse_css_properties(fz_context *ctx, fz_pool *pool, const char *source)
 {
 	struct lexbuf buf;
-	css_lex_init(ctx, &buf, source, "<inline>");
+	css_lex_init(ctx, &buf, pool, source, "<inline>");
 	next(&buf);
 	return parse_declaration_list(&buf);
 }
 
-fz_css_rule *fz_parse_css(fz_context *ctx, fz_css_rule *chain, const char *source, const char *file)
+void fz_parse_css(fz_context *ctx, fz_css *css, const char *source, const char *file)
 {
 	struct lexbuf buf;
-	css_lex_init(ctx, &buf, source, file);
+	css_lex_init(ctx, &buf, css->pool, source, file);
 	next(&buf);
-	return parse_stylesheet(&buf, chain);
+	css->rule = parse_stylesheet(&buf, css->rule);
 }
diff --git a/source/html/html-layout.c b/source/html/html-layout.c
index 34d6f8ac..fb039061 100644
--- a/source/html/html-layout.c
+++ b/source/html/html-layout.c
@@ -112,7 +112,7 @@ struct genstate
 	fz_tree *images;
 	int is_fb2;
 	const char *base_uri;
-	fz_css_rule *css;
+	fz_css *css;
 	int at_bol;
 	int emit_white;
 	int last_brk_cls;
@@ -498,8 +498,11 @@ static void fz_drop_html_box(fz_context *ctx, fz_html_box *box)
 
 void fz_drop_html(fz_context *ctx, fz_html *html)
 {
-	fz_drop_html_box(ctx, html->root);
-	fz_drop_pool(ctx, html->pool);
+	if (html)
+	{
+		fz_drop_html_box(ctx, html->root);
+		fz_drop_pool(ctx, html->pool);
+	}
 }
 
 static fz_html_box *new_box(fz_context *ctx, fz_pool *pool, fz_bidi_direction markup_dir)
@@ -1907,8 +1910,8 @@ static char *concat_text(fz_context *ctx, fz_xml *root)
 	return s;
 }
 
-static fz_css_rule *
-html_load_css(fz_context *ctx, fz_archive *zip, const char *base_uri, fz_css_rule *css, fz_xml *root)
+static void
+html_load_css(fz_context *ctx, fz_archive *zip, const char *base_uri, fz_css *css, fz_xml *root)
 {
 	fz_xml *html, *head, *node;
 	fz_buffer *buf;
@@ -1942,7 +1945,7 @@ html_load_css(fz_context *ctx, fz_archive *zip, const char *base_uri, fz_css_rul
 						{
 							buf = fz_read_archive_entry(ctx, zip, path);
 							fz_write_buffer_byte(ctx, buf, 0);
-							css = fz_parse_css(ctx, css, (char*)buf->data, path);
+							fz_parse_css(ctx, css, (char*)buf->data, path);
 						}
 						fz_always(ctx)
 							fz_drop_buffer(ctx, buf);
@@ -1956,17 +1959,16 @@ html_load_css(fz_context *ctx, fz_archive *zip, const char *base_uri, fz_css_rul
 		{
 			char *s = concat_text(ctx, node);
 			fz_try(ctx)
-				css = fz_parse_css(ctx, css, s, "<style>");
+				fz_parse_css(ctx, css, s, "<style>");
 			fz_catch(ctx)
 				fz_warn(ctx, "ignoring inline stylesheet");
 			fz_free(ctx, s);
 		}
 	}
-	return css;
 }
 
-static fz_css_rule *
-fb2_load_css(fz_context *ctx, fz_archive *zip, const char *base_uri, fz_css_rule *css, fz_xml *root)
+static void
+fb2_load_css(fz_context *ctx, fz_archive *zip, const char *base_uri, fz_css *css, fz_xml *root)
 {
 	fz_xml *fictionbook, *stylesheet;
 
@@ -1976,13 +1978,11 @@ fb2_load_css(fz_context *ctx, fz_archive *zip, const char *base_uri, fz_css_rule
 	{
 		char *s = concat_text(ctx, stylesheet);
 		fz_try(ctx)
-			css = fz_parse_css(ctx, css, s, "<stylesheet>");
+			fz_parse_css(ctx, css, s, "<stylesheet>");
 		fz_catch(ctx)
 			fz_warn(ctx, "ignoring inline stylesheet");
 		fz_free(ctx, s);
 	}
-
-	return css;
 }
 
 static fz_tree *
@@ -2321,11 +2321,12 @@ fz_html *
 fz_parse_html(fz_context *ctx, fz_html_font_set *set, fz_archive *zip, const char *base_uri, fz_buffer *buf, const char *user_css)
 {
 	fz_xml *xml;
-	fz_css_match match;
 	fz_html *html;
+
+	fz_css_match match;
 	struct genstate g;
 
-	g.pool = fz_new_pool(ctx);
+	g.pool = NULL;
 	g.set = set;
 	g.zip = zip;
 	g.base_uri = base_uri;
@@ -2335,46 +2336,62 @@ fz_parse_html(fz_context *ctx, fz_html_font_set *set, fz_archive *zip, const cha
 
 	xml = fz_parse_xml(ctx, buf->data, buf->len, 1);
 
-	if (fz_xml_find(xml, "FictionBook"))
+	g.css = fz_new_css(ctx);
+	fz_try(ctx)
 	{
-		g.is_fb2 = 1;
-		g.css = fz_parse_css(ctx, NULL, fb2_default_css, "<default:fb2>");
-		g.css = fb2_load_css(ctx, g.zip, g.base_uri, g.css, xml);
-		g.images = load_fb2_images(ctx, xml);
+		if (fz_xml_find(xml, "FictionBook"))
+		{
+			g.is_fb2 = 1;
+			fz_parse_css(ctx, g.css, fb2_default_css, "<default:fb2>");
+			fb2_load_css(ctx, g.zip, g.base_uri, g.css, xml);
+			g.images = load_fb2_images(ctx, xml);
+		}
+		else
+		{
+			g.is_fb2 = 0;
+			fz_parse_css(ctx, g.css, html_default_css, "<default:html>");
+			html_load_css(ctx, g.zip, g.base_uri, g.css, xml);
+			g.images = NULL;
+		}
+
+		if (user_css)
+			fz_parse_css(ctx, g.css, user_css, "<user>");
+
+		fz_add_css_font_faces(ctx, g.set, g.zip, g.base_uri, g.css); /* load @font-face fonts into font set */
 	}
-	else
+	fz_catch(ctx)
 	{
-		g.is_fb2 = 0;
-		g.css = fz_parse_css(ctx, NULL, html_default_css, "<default:html>");
-		g.css = html_load_css(ctx, g.zip, g.base_uri, g.css, xml);
-		g.images = NULL;
+		fz_warn(ctx, "ignoring styles due to errors: %s", fz_caught_message(ctx));
 	}
 
-	if (user_css)
-		g.css = fz_parse_css(ctx, g.css, user_css, "<user>");
-
-	// print_rules(g.css);
-
-	fz_add_css_font_faces(ctx, g.set, g.zip, g.base_uri, g.css); /* load @font-face fonts into font set */
-
-	html = fz_malloc_struct(ctx, fz_html);
-	html->pool = g.pool;
-	html->root = new_box(ctx, g.pool, DEFAULT_DIR);
-
-	match.up = NULL;
-	match.count = 0;
-	fz_match_css_at_page(ctx, &match, g.css);
-	fz_apply_css_style(ctx, g.set, &html->root->style, &match);
-	// TODO: transfer page margins out of this hacky box
-
-	generate_boxes(ctx, xml, html->root, &match, 0, DEFAULT_DIR, FZ_LANG_UNSET, &g);
+	g.pool = fz_new_pool(ctx);
+	fz_try(ctx)
+	{
+		html = fz_pool_alloc(ctx, g.pool, sizeof *html);
+		html->pool = g.pool;
+		html->root = new_box(ctx, g.pool, DEFAULT_DIR);
 
-	fz_drop_css(ctx, g.css);
-	fz_drop_xml(ctx, xml);
+		match.up = NULL;
+		match.count = 0;
+		fz_match_css_at_page(ctx, &match, g.css);
+		fz_apply_css_style(ctx, g.set, &html->root->style, &match);
+		// TODO: transfer page margins out of this hacky box
 
-	detect_directionality(ctx, g.pool, html->root);
+		generate_boxes(ctx, xml, html->root, &match, 0, DEFAULT_DIR, FZ_LANG_UNSET, &g);
 
-	fz_drop_tree(ctx, g.images, (void(*)(fz_context*,void*))fz_drop_image);
+		detect_directionality(ctx, g.pool, html->root);
+	}
+	fz_always(ctx)
+	{
+		fz_drop_css(ctx, g.css);
+		fz_drop_xml(ctx, xml);
+		fz_drop_tree(ctx, g.images, (void(*)(fz_context*,void*))fz_drop_image);
+	}
+	fz_catch(ctx)
+	{
+		fz_drop_pool(ctx, g.pool);
+		fz_rethrow(ctx);
+	}
 
 	return html;
 }