plugins: properties: further reduce stack pressure

Follow-up to 9f20c45.

tagtree.c's retrieve_entries has significant stack usage
(>1.5k) and is called from tagtree_entries_iterate.

Further Reduce stack usage of tagtree_entries_iterate,
going from 784 B to 72 B, by using static memory allocation
for the the tagcache_search struct in the Properties plugin.

Change-Id: I75a170bea1c5392c18a891844a0ff31fbd2114eb

apps/plugin.c

@@ -701,6 +701,7 @@ static const struct plugin_api rockbox_api = {
     count_mp3_frames,
     create_xing_header,
 #ifdef HAVE_TAGCACHE
+    tagtree_entries_iterate,
     tagcache_search,
     tagcache_search_set_uniqbuf,
     tagcache_search_add_filter,
@@ -714,9 +715,8 @@ static const struct plugin_api rockbox_api = {
     tagcache_is_in_ram,
 #if defined(HAVE_DIRCACHE)
     tagcache_fill_tags,
-#endif
+#endif /* HAVE_DIRCACHE */
-#endif
+#endif /* HAVE_TC_RAMCACHE */
-    tagtree_entries_iterate,
 #endif /* HAVE_TAGCACHE */
 
 #ifdef HAVE_ALBUMART

apps/plugin.h

@@ -180,7 +180,7 @@ int plugin_open(const char *plugin, const char *parameter);
  * when this happens please take the opportunity to sort in
  * any new functions "waiting" at the end of the list.
  */
-#define PLUGIN_API_VERSION 283
+#define PLUGIN_API_VERSION 284
 
 /* 239 Marks the removal of ARCHOS HWCODEC and CHARCELL */
 
@@ -824,6 +824,9 @@ struct plugin_api {
             void (*progressfunc)(int), bool generate_toc,
             unsigned char* tempbuf, size_t tempbuf_len);
 #ifdef HAVE_TAGCACHE
+    bool (*tagtree_entries_iterate)(struct tagcache_search *tcs,
+                                    bool (*action_cb)(const char *file_name),
+                                    char *buf, size_t buf_sz);
     bool (*tagcache_search)(struct tagcache_search *tcs, int tag);
     void (*tagcache_search_set_uniqbuf)(struct tagcache_search *tcs,
            void *buffer, long length);
@@ -840,10 +843,8 @@ struct plugin_api {
     bool (*tagcache_is_in_ram)(void);
 #if defined(HAVE_DIRCACHE)
     bool (*tagcache_fill_tags)(struct mp3entry *id3, const char *filename);
-#endif
+#endif /* HAVE_DIRCACHE */
-#endif
+#endif /* HAVE_TC_RAMCACHE */
-    bool (*tagtree_entries_iterate)(bool (*action_cb)(const char *file_name),
-                                    char *buf, size_t buf_sz);
 #endif /* HAVE_TAGCACHE */
 
 #ifdef HAVE_ALBUMART

apps/plugins/properties.c

@@ -34,6 +34,9 @@ enum props_types {
     PROPS_DIR
 };
 
+#ifdef HAVE_TAGCACHE
+static struct tagcache_search tcs;
+#endif
 static struct gui_synclist properties_lists;
 static struct mp3entry id3;
 static struct tm tm;
@@ -307,8 +310,8 @@ static bool assemble_track_info(const char *filename, struct dir_stats *stats)
         return false;
 #ifdef HAVE_TAGCACHE
     else if (props_type == PROPS_MUL_ID3 &&
-             !rb->tagtree_entries_iterate(&mul_id3_add, str_filename,
+             !rb->tagtree_entries_iterate(&tcs, &mul_id3_add, str_filename,
-                                                 sizeof str_filename))
+                                                       sizeof str_filename))
         return false;
 #endif
 

apps/tagtree.c

@@ -1795,7 +1795,7 @@ static int retrieve_entries(struct tree_context *c, int offset, bool init)
             { /* Fallback to basename */
                 char *lastname = dptr->name;
                 dptr->name = core_get_data(c->cache.name_buffer_handle)+namebufused;
-                if ((c->cache.name_buffer_size - namebufused) > 0 && 
+                if ((c->cache.name_buffer_size - namebufused) > 0 &&
                     tagcache_retrieve(&tcs, tcs.idx_id, tag_virt_basename, dptr->name,
                                       c->cache.name_buffer_size - namebufused))
                 {
@@ -2654,10 +2654,10 @@ static bool tagtree_insert_selection(int position, bool queue,
  * callback function parameter. Parameter will be NULL for
  * entries whose filename couldn't be retrieved.
  */
-bool tagtree_entries_iterate(bool (*action_cb)(const char *file_name),
+bool tagtree_entries_iterate(struct tagcache_search *tcs,
+                             bool (*action_cb)(const char *file_name),
                              char* buf, size_t buf_sz)
 {
-    struct tagcache_search tcs;
     int i, n;
     unsigned long last_tick;
     int ret = true;
@@ -2668,7 +2668,7 @@ bool tagtree_entries_iterate(bool (*action_cb)(const char *file_name),
     cpu_boost(true);
     if (!goto_allsubentries(newtable))
         ret = false;
-    else if (tagcache_search(&tcs, tag_filename))
+    else if (tagcache_search(tcs, tag_filename))
     {
         last_tick = current_tick + HZ/2;
         splash_progress_set_delay(HZ / 2); /* wait 1/2 sec before progress */
@@ -2684,8 +2684,8 @@ bool tagtree_entries_iterate(bool (*action_cb)(const char *file_name),
                 last_tick = current_tick;
             }
 
-            if (!action_cb(tagcache_retrieve(&tcs, tagtree_get_entry(tc, i)->extraseek,
+            if (!action_cb(tagcache_retrieve(tcs, tagtree_get_entry(tc, i)->extraseek,
-                                             tcs.type, buf, buf_sz) ? buf : NULL))
+                                             tcs->type, buf, buf_sz) ? buf : NULL))
             {
                 ret = false;
                 break;
@@ -2693,7 +2693,7 @@ bool tagtree_entries_iterate(bool (*action_cb)(const char *file_name),
             yield();
         }
 
-        tagcache_search_finish(&tcs);
+        tagcache_search_finish(tcs);
     }
     else
     {

apps/tagtree.h

@@ -47,7 +47,8 @@ int tagtree_get_icon(struct tree_context* c);
 int tagtree_get_filename(struct tree_context* c, char *buf, int buflen);
 int tagtree_get_custom_action(struct tree_context* c);
 bool tagtree_get_subentry_filename(char *buf, size_t bufsize);
-bool tagtree_entries_iterate(bool (*action_cb)(const char *file_name),
+bool tagtree_entries_iterate(struct tagcache_search *tcs,
+                             bool (*action_cb)(const char *file_name),
                              char *buf, size_t buf_sz);
 
 #endif