Fix deadlock in MIDI Map dataFromJson() and onReset() by creating a few Engine::*_NoLock() methods and calling them. Make Engine::updateParamHandle() write-lock instead of read-lock.

include/engine/Engine.hpp

@@ -125,6 +125,7 @@ struct Engine {
 	Read-locks.
 	*/
 	Module* getModule(int64_t moduleId);
+	Module* getModule_NoLock(int64_t moduleId);
 	/** Triggers a ResetEvent for the given Module.
 	Write-locks.
 	*/
@@ -208,15 +209,17 @@ struct Engine {
 	Read-locks.
 	*/
 	ParamHandle* getParamHandle(int64_t moduleId, int paramId);
+	ParamHandle* getParamHandle_NoLock(int64_t moduleId, int paramId);
 	/** Use getParamHandle(moduleId, paramId) instead.
 	Read-locks.
 	*/
 	DEPRECATED ParamHandle* getParamHandle(Module* module, int paramId);
 	/** Sets the ParamHandle IDs and module pointer.
 	If `overwrite` is true and another ParamHandle points to the same param, unsets that one and replaces it with the given handle.
-	Read-locks.
+	Write-locks.
 	*/
 	void updateParamHandle(ParamHandle* paramHandle, int64_t moduleId, int paramId, bool overwrite = true);
+	void updateParamHandle_NoLock(ParamHandle* paramHandle, int64_t moduleId, int paramId, bool overwrite = true);
 
 	/** Serializes the rack.
 	Read-locks.

src/core/MIDIMap.cpp

@@ -159,7 +159,7 @@ struct MIDIMap : Module {
 	void clearMap(int id) {
 		learningId = -1;
 		ccs[id] = -1;
-		APP->engine->updateParamHandle(&paramHandles[id], -1, 0, true);
+		APP->engine->updateParamHandle_NoLock(&paramHandles[id], -1, 0, true);
 		valueFilters[id].reset();
 		updateMapLen();
 		refreshParamHandleText(id);
@@ -169,7 +169,7 @@ struct MIDIMap : Module {
 		learningId = -1;
 		for (int id = 0; id < MAX_CHANNELS; id++) {
 			ccs[id] = -1;
-			APP->engine->updateParamHandle(&paramHandles[id], -1, 0, true);
+			APP->engine->updateParamHandle_NoLock(&paramHandles[id], -1, 0, true);
 			valueFilters[id].reset();
 			refreshParamHandleText(id);
 		}

src/engine/Engine.cpp

@@ -878,6 +878,11 @@ bool Engine::hasModule(Module* module) {
 
 Module* Engine::getModule(int64_t moduleId) {
 	ReadLock lock(internal->mutex);
+	return getModule_NoLock(moduleId);
+}
+
+
+Module* Engine::getModule_NoLock(int64_t moduleId) {
 	auto it = internal->modulesCache.find(moduleId);
 	if (it == internal->modulesCache.end())
 		return NULL;
@@ -1153,6 +1158,11 @@ void Engine::removeParamHandle_NoLock(ParamHandle* paramHandle) {
 
 ParamHandle* Engine::getParamHandle(int64_t moduleId, int paramId) {
 	ReadLock lock(internal->mutex);
+	return getParamHandle_NoLock(moduleId, paramId);
+}
+
+
+ParamHandle* Engine::getParamHandle_NoLock(int64_t moduleId, int paramId) {
 	auto it = internal->paramHandlesCache.find(std::make_tuple(moduleId, paramId));
 	if (it == internal->paramHandlesCache.end())
 		return NULL;
@@ -1166,7 +1176,12 @@ ParamHandle* Engine::getParamHandle(Module* module, int paramId) {
 
 
 void Engine::updateParamHandle(ParamHandle* paramHandle, int64_t moduleId, int paramId, bool overwrite) {
-	ReadLock lock(internal->mutex);
+	WriteLock lock(internal->mutex);
+	updateParamHandle_NoLock(paramHandle, moduleId, paramId, overwrite);
+}
+
+
+void Engine::updateParamHandle_NoLock(ParamHandle* paramHandle, int64_t moduleId, int paramId, bool overwrite) {
 	// Check that it exists
 	auto it = internal->paramHandles.find(paramHandle);
 	assert(it != internal->paramHandles.end());
@@ -1179,8 +1194,7 @@ void Engine::updateParamHandle(ParamHandle* paramHandle, int64_t moduleId, int p
 
 	if (paramHandle->moduleId >= 0) {
 		// Replace old ParamHandle, or reset the current ParamHandle
-		// TODO Maybe call getParamHandle_NoLock()?
-		ParamHandle* oldParamHandle = getParamHandle(moduleId, paramId);
+		ParamHandle* oldParamHandle = getParamHandle_NoLock(moduleId, paramId);
 		if (oldParamHandle) {
 			if (overwrite) {
 				oldParamHandle->moduleId = -1;
@@ -1197,8 +1211,7 @@ void Engine::updateParamHandle(ParamHandle* paramHandle, int64_t moduleId, int p
 
 	// Set module pointer if the above block didn't reset it
 	if (paramHandle->moduleId >= 0) {
-		// TODO Maybe call getModule_NoLock()?
-		paramHandle->module = getModule(paramHandle->moduleId);
+		paramHandle->module = getModule_NoLock(paramHandle->moduleId);
 	}
 
 	Engine_refreshParamHandleCache(this);