Warn if settings.json file is invalid JSON.

include/common.hpp

@@ -13,6 +13,7 @@
 
 // Include some of the C++ stdlib for convenience
 #include <string>
+#include <stdexcept>
 
 
 namespace rack {
@@ -136,4 +137,10 @@ DeferWrapper<F> deferWrapper(F f) {
 #define DEFER(code) auto CONCAT(_defer_, __COUNTER__) = rack::deferWrapper([&]() code)
 
 
+/** Reports a string to the user */
+struct UserException : std::runtime_error {
+	UserException(const std::string &msg) : std::runtime_error(msg) {}
+};
+
+
 } // namespace rack

src/main.cpp

@@ -82,7 +82,6 @@ int main(int argc, char *argv[]) {
 		patchPath = argv[optind];
 	}
 
-	// Initialize environment
 	asset::init();
 	logger::init();
 
@@ -106,6 +105,19 @@ int main(int argc, char *argv[]) {
 	INFO("System directory: %s", asset::systemDir.c_str());
 	INFO("User directory: %s", asset::userDir.c_str());
 
+	// Load settings
+	try {
+		settings::load(asset::user("settings.json"));
+	}
+	catch (UserException &e) {
+		std::string msg = e.what();
+		msg += "\n\nReset settings to default?";
+		if (!osdialog_message(OSDIALOG_WARNING, OSDIALOG_OK_CANCEL, msg.c_str())) {
+			exit(1);
+		}
+	}
+
+	// Check existence of the system res/ directory
 	std::string resDir = asset::system("res");
 	if (!system::isDirectory(resDir)) {
 		std::string message = string::f("Rack's resource directory \"%s\" does not exist. Make sure Rack is correctly installed and launched.", resDir.c_str());
@@ -128,7 +140,6 @@ int main(int argc, char *argv[]) {
 
 	// Initialize app
 	INFO("Initializing app");
-	settings::load(asset::user("settings.json"));
 	appInit();
 
 	const char *openedFilename = glfwGetOpenedFilename();

src/settings.cpp

@@ -230,34 +230,36 @@ void fromJson(json_t *rootJ) {
 void save(const std::string &path) {
 	INFO("Saving settings %s", path.c_str());
 	json_t *rootJ = toJson();
-	if (rootJ) {
-		FILE *file = std::fopen(path.c_str(), "w");
-		if (!file)
-			return;
-
-		json_dumpf(rootJ, file, JSON_INDENT(2) | JSON_REAL_PRECISION(9));
-		json_decref(rootJ);
-		std::fclose(file);
-	}
+	if (!rootJ)
+		return;
+
+	FILE *file = fopen(path.c_str(), "w");
+	if (!file)
+		return;
+	DEFER({
+		fclose(file);
+	});
+
+	json_dumpf(rootJ, file, JSON_INDENT(2) | JSON_REAL_PRECISION(9));
+	json_decref(rootJ);
 }
 
 void load(const std::string &path) {
 	INFO("Loading settings %s", path.c_str());
-	FILE *file = std::fopen(path.c_str(), "r");
+	FILE *file = fopen(path.c_str(), "r");
 	if (!file)
-		return;
+		throw UserException(string::f("Could not load settings file %s", path.c_str()));
+	DEFER({
+		fclose(file);
+	});
 
 	json_error_t error;
 	json_t *rootJ = json_loadf(file, 0, &error);
-	if (rootJ) {
-		fromJson(rootJ);
-		json_decref(rootJ);
-	}
-	else {
-		WARN("JSON parsing error at %s %d:%d %s", error.source, error.line, error.column, error.text);
-	}
+	if (!rootJ)
+		throw UserException(string::f("Settings file has invalid JSON at %d:%d %s", error.line, error.column, error.text));
 
-	std::fclose(file);
+	fromJson(rootJ);
+	json_decref(rootJ);
 }