Both Undo options now write distinct messages in the OSD when buffers

are empty, when undoing fails and when undoing is successful.

Aside from some TODO/FIXME areas added by this fork, the features in the
fork are now complete.

command.c

@@ -1597,12 +1597,25 @@ static void command_event_save_state(const char *path,
 
 static void command_event_undo_save_state(char *s, size_t len)
 {
+   if (content_undo_save_buf_is_empty())
+   {
+      /* TODO/FIXME - use msg_hash_to_str here */
+      snprintf(s, len, "%s",
+         "No save state has been overwritten yet.");
+      return; 
+   }
+
    if (!content_undo_save_state())
    {
       snprintf(s, len, "%s \"%s\".",
             msg_hash_to_str(MSG_FAILED_TO_UNDO_SAVE_STATE),
             "RAM");
+      return;
    }
+
+      /* TODO/FIXME - use msg_hash_to_str here */
+      snprintf(s, len, "%s",
+         "Restored old save state.");
 }
 
 /**
@@ -1635,12 +1648,26 @@ static void command_event_load_state(const char *path, char *s, size_t len)
 
 static void command_event_undo_load_state(char *s, size_t len)
 {
+   
+   if (content_undo_load_buf_is_empty())
+   {
+      /* TODO/FIXME - use msg_hash_to_str here */
+      snprintf(s, len, "%s",
+         "No state has been loaded yet.");
+      return; 
+   }
+
    if (!content_undo_load_state())
    {
       snprintf(s, len, "%s \"%s\".",
             msg_hash_to_str(MSG_FAILED_TO_UNDO_LOAD_STATE),
             "RAM");
-   } 
+      return;
+   }
+
+   /* TODO/FIXME - use msg_hash_to_str here */
+      snprintf(s, len, "%s",
+         "Undid load state.");
 }
 
 static void command_event_main_state(unsigned cmd)

content.h

@@ -79,6 +79,10 @@ bool content_init(void);
 /* Resets the state and savefile backup buffers */
 bool content_reset_savestate_backups();
 
+/* Checks if the buffers are empty */
+bool content_undo_load_buf_is_empty();
+bool content_undo_save_buf_is_empty();
+
 RETRO_END_DECLS
 
 #endif

tasks/task_save_state.c

@@ -65,18 +65,6 @@ struct sram_block
  **/
 bool content_undo_load_state()
 {
-   if (undo_load_buf.data == NULL || undo_load_buf.size == 0) {
-      /* TODO/FIXME - Use msg_hash_to_str in here */
-      /* TODO/FIXME - Should we be using runloop_msg_queue_push in here? */
-
-      RARCH_LOG("%s\n",
-         "No load state to undo.");
-      runloop_msg_queue_push("No load state to undo.", 2, 180, true);
-
-      /* Even though there was no undo, signal this as a success */
-      return true;
-   }
-
    unsigned i;
    //ssize_t size;
    retro_ctx_serialize_info_t serial_info;
@@ -191,9 +179,7 @@ bool content_undo_load_state()
       RARCH_ERR("%s \"%s\".\n",
          msg_hash_to_str(MSG_FAILED_TO_UNDO_LOAD_STATE),
          undo_load_buf.path);
-   } else {
+   } 
-      runloop_msg_queue_push("Undid load state.", 2, 180, true);
-   }
 
    return ret;
 }
@@ -206,15 +192,6 @@ bool content_undo_load_state()
  **/
 bool content_undo_save_state()
 {
-   if (undo_save_buf.data == NULL || undo_save_buf.size == 0)
-   {
-      /* TODO/FIXME - Use msg_hash_to_str in here */
-      RARCH_LOG("%s\n",
-         "No save state to undo.");
-      runloop_msg_queue_push("No save state to undo.", 2, 180, false);
-      return true;
-   }
-
    bool ret = filestream_write_file(undo_save_buf.path, undo_save_buf.data, undo_save_buf.size);
 
    /* Wipe the save file buffer as it's intended to be one use only */
@@ -230,8 +207,6 @@ bool content_undo_save_state()
       RARCH_ERR("%s \"%s\".\n",
          msg_hash_to_str(MSG_FAILED_TO_UNDO_SAVE_STATE),
          undo_save_buf.path);
-   } else {
-      runloop_msg_queue_push("Undid save state.", 2, 180, true);
    }
 
    return ret;
@@ -512,3 +487,13 @@ bool content_reset_savestate_backups()
 
    return true;
 }
+
+bool content_undo_load_buf_is_empty()
+{
+   return undo_load_buf.data == NULL || undo_load_buf.size == 0;
+}
+
+bool content_undo_save_buf_is_empty()
+{
+   return undo_save_buf.data == NULL || undo_save_buf.size == 0;
+}