Script: Add mScriptContextInvoke for context-specific invocation and thread handling

include/mgba/script/context.h

@@ -36,6 +36,7 @@ struct mScriptContext {
 	uint32_t nextCallbackId;
 	struct mScriptValue* constants;
 	struct Table docstrings;
+	int threadDepth;
 };
 
 struct mScriptEngine2 {
@@ -110,6 +111,12 @@ struct VFile;
 bool mScriptContextLoadVF(struct mScriptContext*, const char* name, struct VFile* vf);
 bool mScriptContextLoadFile(struct mScriptContext*, const char* path);
 
+struct mScriptContext* mScriptActiveContext(void);
+bool mScriptContextActivate(struct mScriptContext*);
+void mScriptContextDeactivate(struct mScriptContext*);
+
+bool mScriptContextInvoke(struct mScriptContext*, const struct mScriptValue* fn, struct mScriptFrame* frame);
+
 bool mScriptInvoke(const struct mScriptValue* fn, struct mScriptFrame* frame);
 
 CXX_GUARD_END

src/core/scripting.c

@@ -761,7 +761,7 @@ static int64_t _addCallbackToBreakpoint(struct mScriptDebugger* debugger, struct
 	return cbid;
 }
 
-static void _runCallbacks(struct mScriptBreakpoint* point) {
+static void _runCallbacks(struct mScriptDebugger* debugger, struct mScriptBreakpoint* point) {
 	struct TableIterator iter;
 	if (!HashTableIteratorStart(&point->callbacks, &iter)) {
 		return;
@@ -770,7 +770,7 @@ static void _runCallbacks(struct mScriptBreakpoint* point) {
 		struct mScriptValue* fn = HashTableIteratorGetValue(&point->callbacks, &iter);
 		struct mScriptFrame frame;
 		mScriptFrameInit(&frame);
-		mScriptInvoke(fn, &frame);
+		mScriptContextInvoke(debugger->p->context, fn, &frame);
 		mScriptFrameDeinit(&frame);
 	} while (HashTableIteratorNext(&point->callbacks, &iter));
 }
@@ -812,7 +812,7 @@ static void _scriptDebuggerEntered(struct mDebuggerModule* debugger, enum mDebug
 	default:
 		return;
 	}
-	_runCallbacks(point);
+	_runCallbacks(scriptDebugger, point);
 	debugger->isPaused = false;
 }
 
@@ -1085,7 +1085,7 @@ static bool _callRotationCb(struct mScriptCoreAdapter* adapter, const char* cbNa
 	if (context) {
 		mScriptValueWrap(context, mScriptListAppend(&frame.arguments));
 	}
-	bool ok = mScriptInvoke(cb, &frame);
+	bool ok = mScriptContextInvoke(adapter->context, cb, &frame);
 	if (ok && out && mScriptListSize(&frame.returnValues) == 1) {
 		if (!mScriptCast(mSCRIPT_TYPE_MS_F32, mScriptListGetPointer(&frame.returnValues, 0), out)) {
 			ok = false;
@@ -1154,7 +1154,7 @@ static uint8_t _readLuminance(struct GBALuminanceSource* luminance) {
 	if (adapter->luminanceCb) {
 		struct mScriptFrame frame;
 		mScriptFrameInit(&frame);
-		bool ok = mScriptInvoke(adapter->luminanceCb, &frame);
+		bool ok = mScriptContextInvoke(adapter->context, adapter->luminanceCb, &frame);
 		struct mScriptValue out = {0};
 		if (ok && mScriptListSize(&frame.returnValues) == 1) {
 			if (!mScriptCast(mSCRIPT_TYPE_MS_U8, mScriptListGetPointer(&frame.returnValues, 0), &out)) {

src/script/context.c

@@ -7,6 +7,27 @@
 #ifdef USE_LUA
 #include <mgba/internal/script/lua.h>
 #endif
+#include <mgba-util/threading.h>
+
+static ThreadLocal _threadContext;
+
+#ifdef USE_PTHREADS
+static pthread_once_t _contextOnce = PTHREAD_ONCE_INIT;
+
+static void _createTLS(void) {
+	ThreadLocalInitKey(&_threadContext);
+}
+#elif _WIN32
+static INIT_ONCE _contextOnce = INIT_ONCE_STATIC_INIT;
+
+static BOOL CALLBACK _createTLS(PINIT_ONCE once, PVOID param, PVOID* context) {
+	UNUSED(once);
+	UNUSED(param);
+	UNUSED(context);
+	ThreadLocalInitKey(&_threadContext);
+	return TRUE;
+}
+#endif
 
 #define KEY_NAME_MAX 128
 
@@ -74,6 +95,11 @@ static void _freeTable(void* data) {
 }
 
 void mScriptContextInit(struct mScriptContext* context) {
+#ifdef USE_PTHREADS
+	pthread_once(&_contextOnce, _createTLS);
+#elif _WIN32
+	InitOnceExecuteOnce(&_contextOnce, _createTLS, NULL, 0);
+#endif
 	HashTableInit(&context->rootScope, 0, (void (*)(void*)) mScriptValueDeref);
 	HashTableInit(&context->engines, 0, _engineContextDestroy);
 	mScriptListInit(&context->refPool, 0);
@@ -84,6 +110,7 @@ void mScriptContextInit(struct mScriptContext* context) {
 	context->nextCallbackId = 1;
 	context->constants = NULL;
 	HashTableInit(&context->docstrings, 0, NULL);
+	context->threadDepth = 0;
 }
 
 void mScriptContextDeinit(struct mScriptContext* context) {
@@ -241,7 +268,7 @@ void mScriptContextTriggerCallback(struct mScriptContext* context, const char* c
 			if (args) {
 				mScriptListCopy(&frame.arguments, args);
 			}
-			mScriptInvoke(fn, &frame);
+			mScriptContextInvoke(context, fn, &frame);
 			mScriptFrameDeinit(&frame);
 		}
 
@@ -407,6 +434,48 @@ bool mScriptContextLoadFile(struct mScriptContext* context, const char* path) {
 	return ret;
 }
 
+struct mScriptContext* mScriptActiveContext(void) {
+	return ThreadLocalGetValue(_threadContext);
+}
+
+bool mScriptContextActivate(struct mScriptContext* context) {
+	struct mScriptContext* threadContext = ThreadLocalGetValue(_threadContext);
+	if (threadContext && threadContext != context) {
+		return false;
+	}
+	if (!threadContext && context->threadDepth) {
+		return false;
+	}
+	++context->threadDepth;
+	if (!threadContext) {
+		ThreadLocalSetKey(_threadContext, context);
+	}
+	return true;
+}
+
+void mScriptContextDeactivate(struct mScriptContext* context) {
+#ifndef NDEBUG
+	struct mScriptContext* threadContext = ThreadLocalGetValue(_threadContext);
+	if (threadContext != context) {
+		abort();
+	}
+#endif
+
+	--context->threadDepth;
+	if (!context->threadDepth) {
+		ThreadLocalSetKey(_threadContext, NULL);
+	}
+}
+
+bool mScriptContextInvoke(struct mScriptContext* context, const struct mScriptValue* fn, struct mScriptFrame* frame) {
+	if (!mScriptContextActivate(context)) {
+		return false;
+	}
+	bool res = mScriptInvoke(fn, frame);
+	mScriptContextDeactivate(context);
+	return res;
+}
+
 bool mScriptInvoke(const struct mScriptValue* val, struct mScriptFrame* frame) {
 	if (val->type->base != mSCRIPT_TYPE_FUNCTION) {
 		return false;

src/script/engines/lua.c

@@ -1098,7 +1098,12 @@ bool _luaInvoke(struct mScriptEngineContextLua* luaContext, struct mScriptFrame*
 		luaContext->lastError = NULL;
 	}
 
+	if (!mScriptContextActivate(luaContext->d.context)) {
+		return false;
+	}
+
 	if (frame && !_luaPushFrame(luaContext, &frame->arguments)) {
+		mScriptContextDeactivate(luaContext->d.context);
 		return false;
 	}
 
@@ -1114,6 +1119,7 @@ bool _luaInvoke(struct mScriptEngineContextLua* luaContext, struct mScriptFrame*
 		luaContext->lastError = strdup(lua_tostring(luaContext->lua, -1));
 		lua_pop(luaContext->lua, 1);
 	}
+	mScriptContextDeactivate(luaContext->d.context);
 	if (ret) {
 		return false;
 	}
@@ -1172,7 +1178,7 @@ int _luaThunk(lua_State* lua) {
 
 	struct mScriptValue* fn = lua_touserdata(lua, lua_upvalueindex(1));
 	_autofreeFrame(luaContext->d.context, &frame.arguments);
-	if (!fn || !mScriptInvoke(fn, &frame)) {
+	if (!fn || !mScriptContextInvoke(luaContext->d.context, fn, &frame)) {
 		mScriptContextDrainPool(luaContext->d.context);
 		mScriptFrameDeinit(&frame);
 		luaL_traceback(lua, lua, "Error calling function (invoking failed)", 1);