From 69c379990d83d83682b23eac3ddf390c0d85e976 Mon Sep 17 00:00:00 2001
From: Tor Andersson <tor.andersson@artifex.com>
Date: Wed, 12 Oct 2016 14:45:23 +0200
Subject: 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.
---
 source/html/html-layout.c | 111 ++++++++++++++++++++++++++--------------------
 1 file changed, 64 insertions(+), 47 deletions(-)

(limited to 'source/html/html-layout.c')

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;
 }
-- 
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