Scripting: Allow Lua to pass nested tables to the scripting subsystem

include/mgba/script/types.h

@@ -35,7 +35,7 @@ CXX_GUARD_START
 #define mSCRIPT_TYPE_C_PTR void*
 #define mSCRIPT_TYPE_C_CPTR const void*
 #define mSCRIPT_TYPE_C_LIST struct mScriptList*
-#define mSCRIPT_TYPE_C_TABLE Table*
+#define mSCRIPT_TYPE_C_TABLE struct Table*
 #define mSCRIPT_TYPE_C_WRAPPER struct mScriptValue*
 #define mSCRIPT_TYPE_C_WEAKREF uint32_t
 #define mSCRIPT_TYPE_C_S(STRUCT) struct STRUCT*
@@ -120,6 +120,7 @@ CXX_GUARD_START
 #define mSCRIPT_TYPE_CMP_STR(TYPE) mSCRIPT_TYPE_CMP_GENERIC(mSCRIPT_TYPE_MS_STR, TYPE)
 #define mSCRIPT_TYPE_CMP_CHARP(TYPE) mSCRIPT_TYPE_CMP_GENERIC(mSCRIPT_TYPE_MS_CHARP, TYPE)
 #define mSCRIPT_TYPE_CMP_LIST(TYPE) mSCRIPT_TYPE_CMP_GENERIC(mSCRIPT_TYPE_MS_LIST, TYPE)
+#define mSCRIPT_TYPE_CMP_TABLE(TYPE) mSCRIPT_TYPE_CMP_GENERIC(mSCRIPT_TYPE_MS_TABLE, TYPE)
 #define mSCRIPT_TYPE_CMP_PTR(TYPE) ((TYPE)->base >= mSCRIPT_TYPE_OPAQUE)
 #define mSCRIPT_TYPE_CMP_WRAPPER(TYPE) (true)
 #define mSCRIPT_TYPE_CMP_S(STRUCT) mSCRIPT_TYPE_MS_S(STRUCT)->name == _mSCRIPT_FIELD_NAME

src/script/engines/lua.c

@@ -538,11 +538,13 @@ struct mScriptValue* _luaCoerceFunction(struct mScriptEngineContextLua* luaConte
 	return value;
 }
 
-struct mScriptValue* _luaCoerceTable(struct mScriptEngineContextLua* luaContext) {
+struct mScriptValue* _luaCoerceTable(struct mScriptEngineContextLua* luaContext, struct Table* markedObjects) {
 	struct mScriptValue* table = mScriptValueAlloc(mSCRIPT_TYPE_MS_TABLE);
 	bool isList = true;
 
 	lua_pushnil(luaContext->lua);
+
+	void* tablePointer;
 	while (lua_next(luaContext->lua, -2) != 0) {
 		struct mScriptValue* value = NULL;
 		int type = lua_type(luaContext->lua, -1);
@@ -553,14 +555,23 @@ struct mScriptValue* _luaCoerceTable(struct mScriptEngineContextLua* luaContext)
 		case LUA_TFUNCTION:
 			value = _luaCoerce(luaContext, true);
 			break;
+		case LUA_TTABLE:
+			tablePointer = lua_topointer(luaContext->lua, -1);
+			// Ensure this table doesn't contain any cycles
+			if (!HashTableLookupBinary(markedObjects, &tablePointer, sizeof(tablePointer))) {
+				HashTableInsertBinary(markedObjects, &tablePointer, sizeof(tablePointer), tablePointer);
+				value = _luaCoerceTable(luaContext, markedObjects);
+				if (value) {
+					mScriptValueRef(value);
+				}
+			}
 		default:
-			// Don't let values be something that could contain themselves
 			break;
 		}
 		if (!value) {
-			lua_pop(luaContext->lua, 3);
+			lua_pop(luaContext->lua, type == LUA_TTABLE ? 2 : 3);
 			mScriptValueDeref(table);
-			return false;
+			return NULL;
 		}
 
 		struct mScriptValue* key = NULL;
@@ -628,6 +639,7 @@ struct mScriptValue* _luaCoerce(struct mScriptEngineContextLua* luaContext, bool
 
 	size_t size;
 	const void* buffer;
+	struct Table markedObjects;
 	struct mScriptValue* value = NULL;
 	switch (lua_type(luaContext->lua, -1)) {
 	case LUA_TNIL:
@@ -664,7 +676,10 @@ struct mScriptValue* _luaCoerce(struct mScriptEngineContextLua* luaContext, bool
 		if (!pop) {
 			break;
 		}
-		return _luaCoerceTable(luaContext);
+		HashTableInit(&markedObjects, 0, NULL);
+		value = _luaCoerceTable(luaContext, &markedObjects);
+		HashTableDeinit(&markedObjects);
+		return value;
 	case LUA_TUSERDATA:
 		if (!lua_getmetatable(luaContext->lua, -1)) {
 			break;

src/script/test/lua.c

@@ -66,9 +66,14 @@ static int32_t sum(struct mScriptList* list) {
 	return sum;
 }
 
+static unsigned tableSize(struct Table* table) {
+	return TableSize(table);
+}
+
 mSCRIPT_BIND_FUNCTION(boundIdentityInt, S32, identityInt, 1, S32, a);
 mSCRIPT_BIND_FUNCTION(boundAddInts, S32, addInts, 2, S32, a, S32, b);
 mSCRIPT_BIND_FUNCTION(boundSum, S32, sum, 1, LIST, list);
+mSCRIPT_BIND_FUNCTION(boundTableSize, U32, tableSize, 1, TABLE, table);
 
 mSCRIPT_DECLARE_STRUCT(Test);
 mSCRIPT_DECLARE_STRUCT_D_METHOD(Test, S32, ifn0, 0);
@@ -371,8 +376,50 @@ M_TEST_DEFINE(callCFunc) {
 	assert_true(a.type->equal(&a, val));
 	mScriptValueDeref(val);
 
+	LOAD_PROGRAM("b('a')");
+	assert_false(lua->run(lua));
+
 	mScriptContextDeinit(&context);
 }
+
+M_TEST_DEFINE(callCTable) {
+	SETUP_LUA;
+
+	struct mScriptValue a = mSCRIPT_MAKE_S32(1);
+	struct mScriptValue* val;
+
+	assert_true(lua->setGlobal(lua, "b", &boundTableSize));
+
+	TEST_PROGRAM("assert(b({}) == 0)");
+	assert_null(lua->getError(lua));
+
+	TEST_PROGRAM("assert(b({[2]=1}) == 1)");
+	assert_null(lua->getError(lua));
+
+	TEST_PROGRAM("assert(b({a=1}) == 1)");
+	assert_null(lua->getError(lua));
+
+	TEST_PROGRAM("assert(b({a={}}) == 1)");
+	assert_null(lua->getError(lua));
+
+	LOAD_PROGRAM(
+		"a = {}\n"
+		"a.b = a\n"
+		"assert(b(a) == 1)\n"
+	);
+	assert_false(lua->run(lua));
+
+	LOAD_PROGRAM(
+		"a = {}\n"
+		"a.b = {}\n"
+		"a.b.c = a\n"
+		"assert(b(a) == 1)\n"
+	);
+	assert_false(lua->run(lua));
+
+	mScriptContextDeinit(&context);
+}
+
 M_TEST_DEFINE(globalNull) {
 	SETUP_LUA;
 
@@ -774,6 +821,7 @@ M_TEST_SUITE_DEFINE_SETUP_TEARDOWN(mScriptLua,
 	cmocka_unit_test(rootScope),
 	cmocka_unit_test(callLuaFunc),
 	cmocka_unit_test(callCFunc),
+	cmocka_unit_test(callCTable),
 	cmocka_unit_test(globalNull),
 	cmocka_unit_test(globalStructFieldGet),
 	cmocka_unit_test(globalStructFieldSet),
@@ -782,5 +830,5 @@ M_TEST_SUITE_DEFINE_SETUP_TEARDOWN(mScriptLua,
 	cmocka_unit_test(tableLookup),
 	cmocka_unit_test(tableIterate),
 	cmocka_unit_test(callList),
-	cmocka_unit_test(linkedList)
+	cmocka_unit_test(linkedList),
 )