Scripting: Allow weakrefs to be marked for auto-collection

include/mgba/script/context.h

@@ -89,6 +89,7 @@ uint32_t mScriptContextSetWeakref(struct mScriptContext*, struct mScriptValue* v
 struct mScriptValue* mScriptContextMakeWeakref(struct mScriptContext*, struct mScriptValue* value);
 struct mScriptValue* mScriptContextAccessWeakref(struct mScriptContext*, struct mScriptValue* value);
 void mScriptContextClearWeakref(struct mScriptContext*, uint32_t weakref);
+void mScriptContextDisownWeakref(struct mScriptContext*, uint32_t weakref);
 
 void mScriptContextAttachStdlib(struct mScriptContext* context);
 void mScriptContextAttachSocket(struct mScriptContext* context);

src/script/CMakeLists.txt

@@ -12,8 +12,9 @@ set(TEST_FILES
 if(USE_LUA)
 	list(APPEND SOURCE_FILES engines/lua.c)
 	list(APPEND TEST_FILES
-		test/stdlib.c
+		test/context.c
-		test/lua.c)
+		test/lua.c
+		test/stdlib.c)
 endif()
 
 source_group("Scripting" FILES ${SOURCE_FILES})

src/script/context.c

@@ -71,8 +71,8 @@ void mScriptContextInit(struct mScriptContext* context) {
 
 void mScriptContextDeinit(struct mScriptContext* context) {
 	HashTableDeinit(&context->rootScope);
-	HashTableDeinit(&context->weakrefs);
 	mScriptContextDrainPool(context);
+	HashTableDeinit(&context->weakrefs);
 	mScriptListDeinit(&context->refPool);
 	HashTableDeinit(&context->callbacks);
 	TableDeinit(&context->callbackId);
@@ -102,9 +102,12 @@ void mScriptContextFillPool(struct mScriptContext* context, struct mScriptValue*
 void mScriptContextDrainPool(struct mScriptContext* context) {
 	size_t i;
 	for (i = 0; i < mScriptListSize(&context->refPool); ++i) {
-		struct mScriptValue* value = mScriptValueUnwrap(mScriptListGetPointer(&context->refPool, i));
+		struct mScriptValue* value = mScriptListGetPointer(&context->refPool, i);
-		if (value) {
+		if (value->type->base == mSCRIPT_TYPE_WRAPPER) {
+			value = mScriptValueUnwrap(value);
 			mScriptValueDeref(value);
+		} else if (value->type == mSCRIPT_TYPE_MS_WEAKREF) {
+			mScriptContextClearWeakref(context, value->value.u32);
 		}
 	}
 	mScriptListClear(&context->refPool);
@@ -201,6 +204,13 @@ void mScriptContextClearWeakref(struct mScriptContext* context, uint32_t weakref
 	TableRemove(&context->weakrefs, weakref);
 }
 
+void mScriptContextDisownWeakref(struct mScriptContext* context, uint32_t weakref) {
+	struct mScriptValue* poolEntry = mScriptListAppend(&context->refPool);
+	poolEntry->type = mSCRIPT_TYPE_MS_WEAKREF;
+	poolEntry->value.u32 = weakref;
+	poolEntry->refs = mSCRIPT_VALUE_UNREF;
+}
+
 void mScriptContextTriggerCallback(struct mScriptContext* context, const char* callback) {
 	struct mScriptValue* list = HashTableLookup(&context->callbacks, callback);
 	if (!list) {

src/script/test/context.c

@@ -0,0 +1,103 @@
+/* Copyright (c) 2013-2023 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#include "util/test/suite.h"
+
+#include <mgba/script/context.h>
+#include <mgba/script/macros.h>
+#include <mgba/script/types.h>
+
+M_TEST_DEFINE(weakrefBasic) {
+	struct mScriptContext context;
+	mScriptContextInit(&context);
+
+	struct mScriptValue weakref = mSCRIPT_VAL(WEAKREF, 1);
+	struct mScriptValue fakeVal = mSCRIPT_S32(0x7E57CA5E);
+	struct mScriptValue* val;
+
+	assert_int_equal(TableSize(&context.weakrefs), 0);
+	assert_null(TableLookup(&context.weakrefs, 1));
+	assert_int_equal(context.nextWeakref, 1);
+	assert_null(mScriptContextAccessWeakref(&context, &weakref));
+
+	assert_int_equal(mScriptContextSetWeakref(&context, &fakeVal), 1);
+	assert_int_equal(context.nextWeakref, 2);
+	assert_int_equal(TableSize(&context.weakrefs), 1);
+	val = mScriptContextAccessWeakref(&context, &weakref);
+	assert_non_null(val);
+	assert_int_equal(val->value.u32, 0x7E57CA5E);
+
+	mScriptContextClearWeakref(&context, 1);
+
+	assert_int_equal(TableSize(&context.weakrefs), 0);
+	assert_null(TableLookup(&context.weakrefs, 1));
+	assert_int_equal(context.nextWeakref, 2);
+	assert_null(mScriptContextAccessWeakref(&context, &weakref));
+
+	mScriptContextDeinit(&context);
+}
+
+M_TEST_DEFINE(drainPool) {
+	struct mScriptContext context;
+	mScriptContextInit(&context);
+
+	assert_int_equal(mScriptListSize(&context.refPool), 0);
+
+	struct mScriptValue fakeVal = mSCRIPT_CHARP("foo");
+	fakeVal.refs = 2;
+
+	mScriptContextFillPool(&context, &fakeVal);
+	assert_int_equal(mScriptListSize(&context.refPool), 1);
+	assert_int_equal(fakeVal.refs, 2);
+
+	mScriptContextDrainPool(&context);
+	assert_int_equal(mScriptListSize(&context.refPool), 0);
+	assert_int_equal(fakeVal.refs, 1);
+
+	mScriptContextDeinit(&context);
+}
+
+M_TEST_DEFINE(disownWeakref) {
+	struct mScriptContext context;
+	mScriptContextInit(&context);
+
+	struct mScriptValue weakref = mSCRIPT_VAL(WEAKREF, 1);
+	struct mScriptValue fakeVal = mSCRIPT_S32(0x7E57CA5E);
+	struct mScriptValue* val;
+
+	assert_int_equal(mScriptListSize(&context.refPool), 0);
+	assert_int_equal(TableSize(&context.weakrefs), 0);
+	assert_null(TableLookup(&context.weakrefs, 1));
+	assert_int_equal(context.nextWeakref, 1);
+	assert_null(mScriptContextAccessWeakref(&context, &weakref));
+
+	assert_int_equal(mScriptContextSetWeakref(&context, &fakeVal), 1);
+	assert_int_equal(TableSize(&context.weakrefs), 1);
+	assert_int_equal(context.nextWeakref, 2);
+	val = mScriptContextAccessWeakref(&context, &weakref);
+	assert_non_null(val);
+	assert_int_equal(val->value.u32, 0x7E57CA5E);
+
+	mScriptContextDisownWeakref(&context, 1);
+	assert_int_equal(mScriptListSize(&context.refPool), 1);
+	assert_int_equal(TableSize(&context.weakrefs), 1);
+	val = mScriptContextAccessWeakref(&context, &weakref);
+	assert_non_null(val);
+	assert_int_equal(val->value.u32, 0x7E57CA5E);
+
+	mScriptContextDrainPool(&context);
+	assert_int_equal(mScriptListSize(&context.refPool), 0);
+	assert_int_equal(TableSize(&context.weakrefs), 0);
+	assert_null(TableLookup(&context.weakrefs, 1));
+	assert_null(mScriptContextAccessWeakref(&context, &weakref));
+
+	mScriptContextDeinit(&context);
+}
+
+M_TEST_SUITE_DEFINE(mScript,
+	cmocka_unit_test(weakrefBasic),
+	cmocka_unit_test(drainPool),
+	cmocka_unit_test(disownWeakref),
+)