YAML: Add support for resolving anchors, and use it for GameDB

common/YAML.cpp

@@ -17,7 +17,7 @@ struct RapidYAMLContext
 	Error* error = nullptr;
 };
 
-std::optional<ryml::Tree> ParseYAMLFromString(ryml::csubstr yaml, ryml::csubstr file_name, Error* error)
+std::optional<ryml::Tree> ParseYAMLFromString(ryml::csubstr yaml, ryml::csubstr file_name, Error* error, bool resolve_anchors)
 {
 	RapidYAMLContext context;
 	context.error = error;
@@ -28,40 +28,93 @@ std::optional<ryml::Tree> ParseYAMLFromString(ryml::csubstr yaml, ryml::csubstr
 	callbacks.set_user_data(static_cast<void*>(&context));
 
 	callbacks.set_error_basic([](ryml::csubstr msg, const ryml::ErrorDataBasic& errdata, void* user_data) {
-		std::string description;
-		auto callback = [&description](ryml::csubstr string) {
-			description.append(string.str, string.len);
-		};
-		ryml::err_basic_format(std::move(callback), msg, errdata);
+		RapidYAMLContext* context = static_cast<RapidYAMLContext*>(user_data);
+		// This scope needs to stay, so all objects destruct before std::longjump
+		{
+			std::string description;
+			auto callback = [&description](ryml::csubstr string) {
+				description.append(string.str, string.len);
+			};
+			ryml::err_basic_format(std::move(callback), msg, errdata);
 
-		// We might have already returned, so don't try to recover.
-		pxFailRel(description.c_str());
-		std::abort();
+			if (context != nullptr)
+			{
+				Error::SetString(context->error, std::move(description));
+			}
+			else
+			{
+				pxFailRel(description.c_str());
+			}
+		}
+
+		if (context != nullptr)
+		{
+			std::longjmp(context->env, 1);
+		}
+		else
+		{
+			std::terminate();
+		}
 	});
 
 	callbacks.set_error_parse([](ryml::csubstr msg, const ryml::ErrorDataParse& errdata, void* user_data) {
 		RapidYAMLContext* context = static_cast<RapidYAMLContext*>(user_data);
+		// This scope needs to stay, so all objects destruct before std::longjump
+		{
+			std::string description;
+			auto callback = [&description](ryml::csubstr string) {
+				description.append(string.str, string.len);
+			};
+			ryml::err_parse_format(std::move(callback), msg, errdata);
 
-		std::string description;
-		auto callback = [&description](ryml::csubstr string) {
-			description.append(string.str, string.len);
-		};
-		ryml::err_parse_format(std::move(callback), msg, errdata);
+			if (context != nullptr)
+			{
+				Error::SetString(context->error, std::move(description));
+			}
+			else
+			{
+				pxFailRel(description.c_str());
+			}
+		}
 
-		Error::SetString(context->error, std::move(description));
-		std::longjmp(context->env, 1);
+		if (context != nullptr)
+		{
+			std::longjmp(context->env, 2);
+		}
+		else
+		{
+			std::terminate();
+		}
 	});
 
 	callbacks.set_error_visit([](ryml::csubstr msg, const ryml::ErrorDataVisit& errdata, void* user_data) {
-		std::string description;
-		auto callback = [&description](ryml::csubstr string) {
-			description.append(string.str, string.len);
-		};
-		ryml::err_visit_format(std::move(callback), msg, errdata);
+		RapidYAMLContext* context = static_cast<RapidYAMLContext*>(user_data);
+		// This scope needs to stay, so all objects destruct before std::longjump
+		{
+			std::string description;
+			auto callback = [&description](ryml::csubstr string) {
+				description.append(string.str, string.len);
+			};
+			ryml::err_visit_format(std::move(callback), msg, errdata);
 
-		// We've probably already returned, so don't try to recover.
-		pxFailRel(description.c_str());
-		std::abort();
+			if (context != nullptr)
+			{
+				Error::SetString(context->error, std::move(description));
+			}
+			else
+			{
+				pxFailRel(description.c_str());
+			}
+		}
+
+		if (context != nullptr)
+		{
+			std::longjmp(context->env, 3);
+		}
+		else
+		{
+			std::terminate();
+		}
 	});
 #else
 	callbacks.m_user_data = static_cast<void*>(&context);
@@ -76,15 +129,24 @@ std::optional<ryml::Tree> ParseYAMLFromString(ryml::csubstr yaml, ryml::csubstr
 	ryml::EventHandlerTree event_handler(callbacks);
 	ryml::Parser parser(&event_handler);
 
-	ryml::Tree tree;
+	ryml::Tree tree(callbacks);
 
 	// The only options RapidYAML provides for recovering from errors are
 	// throwing an exception or using setjmp/longjmp. Since we have exceptions
 	// disabled we have to use the latter option.
-	if (setjmp(context.env))
+	if (setjmp(context.env) != 0)
 		return std::nullopt;
 
 	ryml::parse_in_arena(&parser, file_name, yaml, &tree);
+	if (resolve_anchors)
+	{
+		tree.resolve();
+	}
+
+	// Callbacks passed to ryml::Tree are used for value parsing errors later,
+	// so we need to clear the context before it goes out of scope.
+	callbacks.set_user_data(nullptr);
+	tree.callbacks(callbacks);
 
 	return tree;
 }

common/YAML.h

@@ -14,4 +14,6 @@
 /// parsing errors (as is recommended by the documentation for cases where
 /// exceptions are disabled). The file_name parameter is only used for error
 /// messages, which are returned via the error parameter.
-std::optional<ryml::Tree> ParseYAMLFromString(ryml::csubstr yaml, ryml::csubstr file_name, Error* error);
+/// If resolve_anchors is set to true, YAML anchors and aliases will be resolved.
+/// It's a potentially slow operation, so it's opt-in.
+std::optional<ryml::Tree> ParseYAMLFromString(ryml::csubstr yaml, ryml::csubstr file_name, Error* error, bool resolve_anchors = false);

pcsx2/GameDatabase.cpp

@@ -1030,7 +1030,7 @@ void GameDatabase::initDatabase()
 	const ryml::csubstr yaml = ryml::to_csubstr(*buffer);
 
 	Error error;
-	std::optional<ryml::Tree> tree = ParseYAMLFromString(yaml, ryml::to_csubstr(name), &error);
+	std::optional<ryml::Tree> tree = ParseYAMLFromString(yaml, ryml::to_csubstr(name), &error, true);
 	if (!tree.has_value())
 	{
 		Console.ErrorFmt("GameDB: Failed to parse game database file {}:", path);