Don't automatically free temporary memory, let the application call SDL_FreeTemporaryMemory() when it's ready.

Also mark up all functions that return temporary memory with SDL_DECLSPEC_TEMP, to help people implementing language bindings.

Fixes https://github.com/libsdl-org/SDL/issues/10378

src/dynapi/SDL_dynapi.sym

@@ -130,6 +130,7 @@ SDL3_0.0.0 {
     SDL_FlushEvent;
     SDL_FlushEvents;
     SDL_FlushRenderer;
+    SDL_FreeTemporaryMemory;
     SDL_GDKSuspendComplete;
     SDL_GL_CreateContext;
     SDL_GL_DestroyContext;

src/dynapi/SDL_dynapi_overrides.h

@@ -155,6 +155,7 @@
 #define SDL_FlushEvent SDL_FlushEvent_REAL
 #define SDL_FlushEvents SDL_FlushEvents_REAL
 #define SDL_FlushRenderer SDL_FlushRenderer_REAL
+#define SDL_FreeTemporaryMemory SDL_FreeTemporaryMemory_REAL
 #define SDL_GDKSuspendComplete SDL_GDKSuspendComplete_REAL
 #define SDL_GL_CreateContext SDL_GL_CreateContext_REAL
 #define SDL_GL_DestroyContext SDL_GL_DestroyContext_REAL

src/dynapi/SDL_dynapi_procs.h

@@ -175,6 +175,7 @@ SDL_DYNAPI_PROC(int,SDL_FlushAudioStream,(SDL_AudioStream *a),(a),return)
 SDL_DYNAPI_PROC(void,SDL_FlushEvent,(Uint32 a),(a),)
 SDL_DYNAPI_PROC(void,SDL_FlushEvents,(Uint32 a, Uint32 b),(a,b),)
 SDL_DYNAPI_PROC(int,SDL_FlushRenderer,(SDL_Renderer *a),(a),return)
+SDL_DYNAPI_PROC(void,SDL_FreeTemporaryMemory,(void),(),)
 SDL_DYNAPI_PROC(void,SDL_GDKSuspendComplete,(void),(),)
 SDL_DYNAPI_PROC(SDL_GLContext,SDL_GL_CreateContext,(SDL_Window *a),(a),return)
 SDL_DYNAPI_PROC(int,SDL_GL_DestroyContext,(SDL_GLContext a),(a),return)

src/dynapi/gendynapi.py

@@ -197,6 +197,7 @@ def main():
             func_ret = func_ret.replace('extern', ' ')
             func_ret = func_ret.replace('SDLCALL', ' ')
             func_ret = func_ret.replace('SDL_DECLSPEC', ' ')
+            func_ret = func_ret.replace('SDL_DECLSPEC_TEMP', ' ')
             # Remove trailing spaces in front of '*'
             tmp = ""
             while func_ret != tmp:

src/events/SDL_events.c

@@ -79,7 +79,6 @@ static Uint32 SDL_userevents = SDL_EVENT_USER;
 typedef struct SDL_TemporaryMemory
 {
     void *memory;
-    Uint64 timestamp;
     struct SDL_TemporaryMemory *prev;
     struct SDL_TemporaryMemory *next;
 } SDL_TemporaryMemory;
@@ -111,7 +110,6 @@ static struct
     SDL_EventEntry *free;
 } SDL_EventQ = { NULL, SDL_FALSE, { 0 }, 0, NULL, NULL, NULL };
 
-static void SDL_FreeTemporaryMemory(void);
 
 static void SDL_CleanupTemporaryMemory(void *data)
 {
@@ -268,23 +266,6 @@ static void SDL_TransferTemporaryMemoryFromEvent(SDL_EventEntry *event)
     event->memory = NULL;
 }
 
-static void SDL_CollectTemporaryMemory(SDL_TemporaryMemoryState *state, Uint64 now)
-{
-    // Temporary memory will age out and be collected after 1 second
-    const int TEMPORARY_MEMORY_COLLECT_TIME_MS = 1000;
-
-    while (state->head) {
-        SDL_TemporaryMemory *entry = state->head;
-
-        if ((now - entry->timestamp) < TEMPORARY_MEMORY_COLLECT_TIME_MS) {
-            break;
-        }
-
-        SDL_UnlinkTemporaryMemoryEntry(state, entry);
-        SDL_FreeTemporaryMemoryEntry(state, entry, SDL_TRUE);
-    }
-}
-
 void *SDL_FreeLater(void *memory)
 {
     SDL_TemporaryMemoryState *state;
@@ -301,16 +282,12 @@ void *SDL_FreeLater(void *memory)
         return memory;  // this is now a leak, but you probably have bigger problems if malloc failed.
     }
 
-    Uint64 now = SDL_GetTicks();
-    SDL_CollectTemporaryMemory(state, now);
-
     SDL_TemporaryMemory *entry = (SDL_TemporaryMemory *)SDL_malloc(sizeof(*entry));
     if (!entry) {
         return memory;  // this is now a leak, but you probably have bigger problems if malloc failed. We could probably pool up and reuse entries, though.
     }
 
     entry->memory = memory;
-    entry->timestamp = now;
 
     SDL_LinkTemporaryMemoryEntry(state, entry);
 
@@ -885,8 +862,6 @@ void SDL_StopEventLoop(void)
     SDL_EventQ.free = NULL;
     SDL_AtomicSet(&SDL_sentinel_pending, 0);
 
-    SDL_FreeTemporaryMemory();
-
     /* Clear disabled event state */
     for (i = 0; i < SDL_arraysize(SDL_disabled_events); ++i) {
         SDL_free(SDL_disabled_events[i]);
@@ -1183,9 +1158,6 @@ void SDL_FlushEvents(Uint32 minType, Uint32 maxType)
 /* Run the system dependent event loops */
 static void SDL_PumpEventsInternal(SDL_bool push_sentinel)
 {
-    /* Free old event memory */
-    SDL_FreeTemporaryMemory();
-
     /* Release any keys held down from last frame */
     SDL_ReleaseAutoReleaseKeys();