Clean up autosave directory of removed modules when saving a patch and closing. Check for magic number of Zstandard format to find out whether a patch is legacy pre-v2.

include/patch.hpp

@@ -26,6 +26,7 @@ struct PatchManager {
 	void saveAsDialog();
 	void saveTemplateDialog();
 	void saveAutosave();
+	void cleanAutosave();
 	/** Loads a patch and nothing else.
 	Returns whether the patch was loaded successfully.
 	*/

src/context.cpp

@@ -12,23 +12,22 @@ namespace rack {
 
 Context::~Context() {
 	// Set pointers to NULL so other objects will segfault when attempting to access them
-	if (scene)
-		delete scene;
+	delete patch;
+	patch = NULL;
+
+	delete scene;
 	scene = NULL;
-	if (event)
-		delete event;
-	event = NULL;
-	if (history)
-		delete history;
-	history = NULL;
-	if (window)
-		delete window;
+
+	delete window;
 	window = NULL;
-	if (patch)
-		delete patch;
-	patch = NULL;
-	if (engine)
-		delete engine;
+
+	delete history;
+	history = NULL;
+
+	delete event;
+	event = NULL;
+
+	delete engine;
 	engine = NULL;
 }
 

src/patch.cpp

@@ -27,6 +27,7 @@ PatchManager::PatchManager() {
 
 
 PatchManager::~PatchManager() {
+	cleanAutosave();
 }
 
 
@@ -60,7 +61,9 @@ static bool promptClear(std::string text) {
 
 void PatchManager::save(std::string path) {
 	INFO("Saving patch %s", path.c_str());
+	// TEMP
 	saveAutosave();
+	cleanAutosave();
 
 	uint64_t startTime = system::getNanoseconds();
 	// Set compression level to 1 so that a 500MB/s SSD is almost bottlenecked
@@ -169,16 +172,35 @@ void PatchManager::saveAutosave() {
 }
 
 
+void PatchManager::cleanAutosave() {
+	// Remove files and folders in the `autosave/modules` folder that doesn't match a module in the rack.
+	std::string modulesDir = system::join(asset::autosavePath, "modules");
+	for (const std::string& entry : system::getEntries(modulesDir)) {
+		try {
+			int64_t moduleId = std::stol(system::getFilename(entry));
+			// Ignore modules that exist in the rack
+			if (APP->engine->getModule(moduleId))
+				continue;
+		}
+		catch (std::invalid_argument& e) {
+		}
+		// Remove the entry.
+		system::removeRecursively(entry);
+	}
+}
+
+
 static bool isPatchLegacyPre2(std::string path) {
 	FILE* f = std::fopen(path.c_str(), "rb");
 	if (!f)
 		return false;
 	DEFER({std::fclose(f);});
-	// Read first byte and check if it's a "{" character.
-	// TODO Is it possible for .tar.zst files to start with the same character?
-	char buf[1] = {};
+	// All Zstandard frames start with this magic number.
+	char zstdMagic[] = "\x28\xb5\x2f\xfd";
+	char buf[4] = {};
 	std::fread(buf, 1, sizeof(buf), f);
-	return std::memcmp(buf, "{", 1) == 0;
+	// If the patch file doesn't begin with the magic number, it's a legacy patch.
+	return std::memcmp(buf, zstdMagic, sizeof(buf)) != 0;
 }