From 68d7411edff1a110b96fca853d6b22f1a1dce1c0 Mon Sep 17 00:00:00 2001
From: twinaphex <libretro@gmail.com>
Date: Sat, 18 May 2019 03:28:54 +0200
Subject: [PATCH] (menu entries) Add sublabel_cache - this should prevent
 unnecessary function calls if the contents of a sublabel don't change over
 time

---
 menu/cbs/menu_cbs_sublabel.c |  6 +++---
 menu/menu_entries.c          | 26 +++++++++++++++++++-------
 menu/menu_entries.h          |  2 ++
 3 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/menu/cbs/menu_cbs_sublabel.c b/menu/cbs/menu_cbs_sublabel.c
index dc025c8d2d..02a137e9d3 100644
--- a/menu/cbs/menu_cbs_sublabel.c
+++ b/menu/cbs/menu_cbs_sublabel.c
@@ -55,7 +55,7 @@
   static int (func_name)(file_list_t *list, unsigned type, unsigned i, const char *label, const char *path, char *s, size_t len) \
 { \
    strlcpy(s, msg_hash_to_str(lbl), len); \
-   return 0; \
+   return 1; \
 }
 
 default_sublabel_macro(menu_action_sublabel_setting_audio_mixer_add_to_mixer_and_play,
@@ -708,7 +708,7 @@ static int action_bind_sublabel_audio_mixer_stream(
    audio_mixer_stream_t *stream = audio_driver_mixer_get_stream(offset);
 
    if (!stream)
-      return 0;
+      return -1;
 
    switch (stream->state)
    {
@@ -796,7 +796,7 @@ static int action_bind_sublabel_netplay_room(
    unsigned offset        = i - 3;
 
    if (i < 1 || offset > (unsigned)netplay_room_count)
-      return 0;
+      return -1;
 
    ra_version = netplay_room_list[offset].retroarch_version;
    corename   = netplay_room_list[offset].corename;
diff --git a/menu/menu_entries.c b/menu/menu_entries.c
index 2ddc72385e..c070ab664a 100644
--- a/menu/menu_entries.c
+++ b/menu/menu_entries.c
@@ -433,14 +433,26 @@ void menu_entry_get(menu_entry_t *entry, size_t stack_idx,
          char tmp[512];
          tmp[0] = '\0';
 
-         cbs->action_sublabel(list,
-               entry->type, (unsigned)i,
-               label, path,
-               tmp,
-               sizeof(tmp));
+         if (!string_is_empty(cbs->action_sublabel_cache))
+            entry->sublabel = strdup(cbs->action_sublabel_cache);
+         else
+         {
+            if (cbs->action_sublabel(list,
+                     entry->type, (unsigned)i,
+                     label, path,
+                     tmp,
+                     sizeof(tmp)))
+            {
+               /* if this function callback returns true,
+                * we know that the value won't change - so we
+                * can cache it instead. */
+               strlcpy(cbs->action_sublabel_cache,
+                     tmp, sizeof(cbs->action_sublabel_cache));
+            }
 
-         if (!string_is_empty(tmp))
-            entry->sublabel = strdup(tmp);
+            if (!string_is_empty(tmp))
+               entry->sublabel = strdup(tmp);
+         }
       }
    }
 
diff --git a/menu/menu_entries.h b/menu/menu_entries.h
index ca94e50e95..6baddb93d3 100644
--- a/menu/menu_entries.h
+++ b/menu/menu_entries.h
@@ -80,6 +80,8 @@ typedef struct menu_ctx_list
 
 typedef struct menu_file_list_cbs
 {
+   char action_sublabel_cache[512];
+
    enum msg_hash_enums enum_idx;
    const char *action_iterate_ident;
    const char *action_deferred_push_ident;