From 44ab21ab35d2ede6f8fc1e9391c0271bc0e58146 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Mon, 1 May 2023 04:44:03 -0700
Subject: [PATCH] Scripting: Allow callbacks to access weakrefs

---
 src/script/context.c     | 23 +++++++++++++++------
 src/script/test/stdlib.c | 44 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+), 6 deletions(-)

diff --git a/src/script/context.c b/src/script/context.c
index 352c4d278..85c3de485 100644
--- a/src/script/context.c
+++ b/src/script/context.c
@@ -235,12 +235,15 @@ void mScriptContextTriggerCallback(struct mScriptContext* context, const char* c
 	do {
 		struct mScriptFrame frame;
 		struct mScriptCallbackInfo* info = TableIteratorGetValue(table, &iter);
-		mScriptFrameInit(&frame);
-		if (args) {
-			mScriptListCopy(&frame.arguments, args);
+		struct mScriptValue* fn = mScriptContextAccessWeakref(context, info->fn);
+		if (fn) {
+			mScriptFrameInit(&frame);
+			if (args) {
+				mScriptListCopy(&frame.arguments, args);
+			}
+			mScriptInvoke(fn, &frame);
+			mScriptFrameDeinit(&frame);
 		}
-		mScriptInvoke(info->fn, &frame);
-		mScriptFrameDeinit(&frame);
 
 		if (info->oneshot) {
 			*UInt32ListAppend(&oneshots) = info->id;
@@ -255,7 +258,15 @@ void mScriptContextTriggerCallback(struct mScriptContext* context, const char* c
 }
 
 static uint32_t mScriptContextAddCallbackInternal(struct mScriptContext* context, const char* callback, struct mScriptValue* fn, bool oneshot) {
-	if (fn->type->base != mSCRIPT_TYPE_FUNCTION) {
+	if (fn->type == mSCRIPT_TYPE_MS_WEAKREF) {
+		struct mScriptValue* weakref = mScriptContextAccessWeakref(context, fn);
+		if (!weakref) {
+			return 0;
+		}
+		if (weakref->type->base != mSCRIPT_TYPE_FUNCTION) {
+			return 0;
+		}
+	} else if (fn->type->base != mSCRIPT_TYPE_FUNCTION) {
 		return 0;
 	}
 	struct Table* table = HashTableLookup(&context->callbacks, callback);
diff --git a/src/script/test/stdlib.c b/src/script/test/stdlib.c
index 852894a34..eda6deb7b 100644
--- a/src/script/test/stdlib.c
+++ b/src/script/test/stdlib.c
@@ -126,9 +126,53 @@ M_TEST_DEFINE(oneshot) {
 	mScriptContextDeinit(&context);
 }
 
+static void _tableIncrement(struct mScriptValue* table) {
+	assert_non_null(table);
+	struct mScriptValue* value = mScriptTableLookup(table, &mSCRIPT_MAKE_CHARP("key"));
+	assert_non_null(value);
+	assert_ptr_equal(value->type, mSCRIPT_TYPE_MS_S32);
+	++value->value.s32;
+}
+
+mSCRIPT_BIND_VOID_FUNCTION(tableIncrement, _tableIncrement, 1, WTABLE, table);
+
+M_TEST_DEFINE(callbackWeakref) {
+	SETUP_LUA;
+
+	struct mScriptValue* table = mScriptValueAlloc(mSCRIPT_TYPE_MS_TABLE);
+	struct mScriptList args;
+	mScriptListInit(&args, 1);
+	mScriptValueWrap(table, mScriptListAppend(&args));
+	struct mScriptValue* lambda = mScriptLambdaCreate0(&tableIncrement, &args);
+	mScriptListDeinit(&args);
+	struct mScriptValue* weakref = mScriptContextMakeWeakref(&context, lambda);
+	mScriptContextAddCallback(&context, "test", weakref);
+
+	struct mScriptValue* key = mScriptStringCreateFromUTF8("key");
+	struct mScriptValue* value = mScriptValueAlloc(mSCRIPT_TYPE_MS_S32);
+	value->value.s32 = 1;
+	mScriptTableInsert(table, key, value);
+
+	mScriptContextTriggerCallback(&context, "test", NULL);
+	assert_int_equal(value->value.s32, 2);
+
+	mScriptContextClearWeakref(&context, weakref->value.u32);
+	mScriptValueDeref(weakref);
+
+	mScriptContextTriggerCallback(&context, "test", NULL);
+	assert_int_equal(value->value.s32, 2);
+
+	mScriptValueDeref(table);
+	mScriptValueDeref(key);
+	mScriptValueDeref(value);
+
+	mScriptContextDeinit(&context);
+}
+
 M_TEST_SUITE_DEFINE_SETUP_TEARDOWN(mScriptStdlib,
 	cmocka_unit_test(bitMask),
 	cmocka_unit_test(bitUnmask),
 	cmocka_unit_test(callbacks),
 	cmocka_unit_test(oneshot),
+	cmocka_unit_test(callbackWeakref),
 )