utils: add hint to enable/disable object validity checks

Author: mechakotik

include/SDL3/SDL_hints.h

@@ -591,6 +591,25 @@ extern "C" {
  */
 #define SDL_HINT_CAMERA_DRIVER "SDL_CAMERA_DRIVER"
 
+/**
+ * A variable that controls whether object validity checks are enabled.
+ *
+ * Object validity checks prevent undefined behaviour when passing invalid
+ * pointers to SDL functions. A function will return invalid argument error
+ * if you pass pointer to unitialized/freed SDL object. You may want to
+ * disable these checks to improve performance.
+ *
+ * The variable can be set to the following values:
+ *
+ * - "0": Disable object validity checks
+ * - "1": Enable object validity checks
+ *
+ * This hint should be set before SDL is initialized.
+ *
+ * \since This hint is avaliable since ???
+ */
+#define SDL_HINT_CHECK_OBJECT_VALIDITY "SDL_CHECK_OBJECT_VALIDITY"
+
 /**
  * A variable that limits what CPU features are available.
  *

src/SDL_utils.c

@@ -18,6 +18,7 @@
      misrepresented as being the original software.
   3. This notice may not be removed or altered from any source distribution.
 */
+#include "SDL3/SDL_hints.h"
 #include "SDL_internal.h"
 
 #if defined(HAVE_GETHOSTNAME) && !defined(SDL_PLATFORM_WINDOWS)
@@ -137,6 +138,7 @@ Uint32 SDL_GetNextObjectID(void)
 
 static SDL_InitState SDL_objects_init;
 static SDL_HashTable *SDL_objects;
+static bool check_validity = true;
 
 static Uint32 SDLCALL SDL_HashObject(void *unused, const void *key)
 {
@@ -153,6 +155,11 @@ void SDL_SetObjectValid(void *object, SDL_ObjectType type, bool valid)
     SDL_assert(object != NULL);
 
     if (SDL_ShouldInit(&SDL_objects_init)) {
+        check_validity = SDL_GetHintBoolean(SDL_HINT_CHECK_OBJECT_VALIDITY, true);
+        if(!check_validity) {
+            SDL_SetInitialized(&SDL_objects_init, true);
+            return;
+        }
         SDL_objects = SDL_CreateHashTable(0, true, SDL_HashObject, SDL_KeyMatchObject, NULL, NULL);
         const bool initialized = (SDL_objects != NULL);
         SDL_SetInitialized(&SDL_objects_init, initialized);
@@ -161,10 +168,12 @@ void SDL_SetObjectValid(void *object, SDL_ObjectType type, bool valid)
         }
     }
 
-    if (valid) {
-        SDL_InsertIntoHashTable(SDL_objects, object, (void *)(uintptr_t)type, true);
-    } else {
-        SDL_RemoveFromHashTable(SDL_objects, object);
+    if (check_validity) {
+        if (valid) {
+            SDL_InsertIntoHashTable(SDL_objects, object, (void *)(uintptr_t)type, true);
+        } else {
+            SDL_RemoveFromHashTable(SDL_objects, object);
+        }
     }
 }
 
@@ -174,6 +183,10 @@ bool SDL_ObjectValid(void *object, SDL_ObjectType type)
         return false;
     }
 
+    if (!check_validity) {
+        return true;
+    }
+
     const void *object_type;
     if (!SDL_FindInHashTable(SDL_objects, object, &object_type)) {
         return false;
@@ -205,6 +218,9 @@ static bool SDLCALL GetOneObject(void *userdata, const SDL_HashTable *table, con
 
 int SDL_GetObjects(SDL_ObjectType type, void **objects, int count)
 {
+    if (!check_validity) {
+        return 0;
+    }
     GetOneObjectData data = { type, objects, count, 0 };
     SDL_IterateHashTable(SDL_objects, GetOneObject, &data);
     return data.num_objects;
@@ -236,11 +252,13 @@ static bool SDLCALL LogOneLeakedObject(void *userdata, const SDL_HashTable *tabl
 void SDL_SetObjectsInvalid(void)
 {
     if (SDL_ShouldQuit(&SDL_objects_init)) {
-        // Log any leaked objects
-        SDL_IterateHashTable(SDL_objects, LogOneLeakedObject, NULL);
-        SDL_assert(SDL_HashTableEmpty(SDL_objects));
-        SDL_DestroyHashTable(SDL_objects);
-        SDL_objects = NULL;
+        if (check_validity) {
+            // Log any leaked objects
+            SDL_IterateHashTable(SDL_objects, LogOneLeakedObject, NULL);
+            SDL_assert(SDL_HashTableEmpty(SDL_objects));
+            SDL_DestroyHashTable(SDL_objects);
+            SDL_objects = NULL;
+        }
         SDL_SetInitialized(&SDL_objects_init, false);
     }
 }