From ac8f149e0d78cd8ca2a776766ca78c1fd7655e40 Mon Sep 17 00:00:00 2001
From: Vsevolod Stakhov <vsevolod@highsecure.ru>
Date: Fri, 23 Jul 2021 17:31:54 +0100
Subject: [PATCH] [Minor] Css: Slightly fix error propagation

---
 src/libserver/css/css_parser.cxx  | 21 ++++++++++++++-------
 src/libserver/css/parse_error.hxx |  1 +
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/src/libserver/css/css_parser.cxx b/src/libserver/css/css_parser.cxx
index 1ab46a4ec..4a545db4e 100644
--- a/src/libserver/css/css_parser.cxx
+++ b/src/libserver/css/css_parser.cxx
@@ -166,7 +166,7 @@ public:
 	 * Process a single css rule
 	 */
 	std::unique_ptr<css_consumed_block> consume_css_rule(const std::string_view &sv);
-	bool consume_input(const std::string_view &sv);
+	std::optional<css_parse_error> consume_input(const std::string_view &sv);
 
 	auto get_object_maybe(void) -> tl::expected<std::shared_ptr<css_style_sheet>, css_parse_error> {
 		if (style_object) {
@@ -599,13 +599,20 @@ css_parser::consume_css_rule(const std::string_view &sv) -> std::unique_ptr<css_
 	return rule_block;
 }
 
-bool css_parser::consume_input(const std::string_view &sv)
+std::optional<css_parse_error>
+css_parser::consume_input(const std::string_view &sv)
 {
 	auto &&consumed_blocks = consume_css_blocks(sv);
 	const auto &rules = consumed_blocks->get_blocks_or_empty();
 
 	if (rules.empty()) {
-		return false;
+		if (error.type == css_parse_error_type::PARSE_ERROR_UNKNOWN_ERROR) {
+			return css_parse_error(css_parse_error_type::PARSE_ERROR_EMPTY,
+					"no css rules consumed");
+		}
+		else {
+			return error;
+		}
 	}
 
 	if (!style_object) {
@@ -691,7 +698,7 @@ bool css_parser::consume_input(const std::string_view &sv)
 	auto debug_str = consumed_blocks->debug_str();
 	msg_debug_css("consumed css: {%*s}", (int)debug_str.size(), debug_str.data());
 
-	return true;
+	return std::nullopt;
 }
 
 auto
@@ -779,12 +786,12 @@ auto parse_css(rspamd_mempool_t *pool, const std::string_view &st,
 		processed_input = std::string_view{nspace, st.size()};
 	}
 
-	if (parser.consume_input(processed_input)) {
+	auto maybe_error = parser.consume_input(processed_input);
+	if (!maybe_error) {
 		return parser.get_object_maybe();
 	}
 
-	return tl::make_unexpected(css_parse_error{css_parse_error_type::PARSE_ERROR_INVALID_SYNTAX,
-											   "cannot parse input"});
+	return tl::make_unexpected(maybe_error.value());
 }
 
 auto
diff --git a/src/libserver/css/parse_error.hxx b/src/libserver/css/parse_error.hxx
index 450c49d68..a493e993f 100644
--- a/src/libserver/css/parse_error.hxx
+++ b/src/libserver/css/parse_error.hxx
@@ -31,6 +31,7 @@ enum class css_parse_error_type {
 	PARSE_ERROR_UNKNOWN_OPTION,
 	PARSE_ERROR_INVALID_SYNTAX,
 	PARSE_ERROR_BAD_NESTING,
+	PARSE_ERROR_EMPTY,
 	PARSE_ERROR_NYI,
 	PARSE_ERROR_UNKNOWN_ERROR,
 	PARSE_ERROR_NO_ERROR,
-- 
2.39.5