tagtree add crc check so we can reuse already loaded entries

If you have a lot of tracks loaded in a database view and play a
track it builds a playlist and puts you into the wps

if you stop playback and exit the WPS you are immediately
loading entries that were just loaded

if you return to the database again reload data thats probably
still there

this patch gets a crc of the data and if it matches reuses it in
the tagtree rather than reloading it

Change-Id: Ice3aba7569f19afdd1627ba18c2dc781f98cbf93

1 files changed, 39 insertions, 0 deletions

diff --git a/apps/tagtree.c b/apps/tagtree.c
index 126fb04678..1a49936f45 100644
--- a/apps/tagtree.c
+++ b/apps/tagtree.c
@@ -66,6 +66,10 @@
 
 static int tagtree_play_folder(struct tree_context* c);
 
+/* reuse of tagtree data after tagtree_play_folder() */
+static uint32_t loaded_entries_crc = 0;
+
+
 /* this needs to be same size as struct entry (tree.h) and name needs to be
  * the first; so that they're compatible enough to walk arrays of both
  * derefencing the name member*/
@@ -280,6 +284,20 @@ static struct buflib_callbacks ops = {
     .shrink_callback = NULL,
 };
 
+static uint32_t tagtree_data_crc(struct tree_context* c)
+{
+    char* buf;
+    uint32_t crc;
+    buf = core_get_data(tagtree_handle); /* data for the search clauses etc */
+    crc = crc_32(buf, tagtree_buf_used, c->dirlength);
+    buf = core_get_data(c->cache.name_buffer_handle); /* names */
+    crc = crc_32(buf, c->cache.name_buffer_size, crc);
+    buf = core_get_data(c->cache.entries_handle); /* tagentries */
+    crc = crc_32(buf, c->cache.max_entries * sizeof(struct tagentry), crc);
+    logf("%s 0x%x", __func__, crc);
+    return crc;
+}
+
 static void* tagtree_alloc(size_t size)
 {
     size = ALIGN_UP(size, sizeof(void*));
@@ -1813,6 +1831,8 @@ static int load_root(struct tree_context *c)
 
 int tagtree_load(struct tree_context* c)
 {
+    logf( "%s", __func__);
+
     int count;
     int table = c->currtable;
 
@@ -1829,12 +1849,24 @@ int tagtree_load(struct tree_context* c)
     switch (table)
     {
         case TABLE_ROOT:
+            logf( "root...");
             count = load_root(c);
             break;
 
         case TABLE_ALLSUBENTRIES:
         case TABLE_NAVIBROWSE:
             logf("navibrowse...");
+
+            if (loaded_entries_crc != 0)
+            {
+                if (loaded_entries_crc == tagtree_data_crc(c))
+                {
+                    count = c->dirlength;
+                    logf("Reusing %d entries", count);
+                    break;
+                }
+            }
+
             cpu_boost(true);
             count = retrieve_entries(c, 0, true);
             cpu_boost(false);
@@ -1845,6 +1877,8 @@ int tagtree_load(struct tree_context* c)
             return -1;
     }
 
+    loaded_entries_crc = 0;
+
     if (count < 0)
     {
         if (count != RELOAD_TAGTREE)
@@ -1877,6 +1911,8 @@ int tagtree_load(struct tree_context* c)
  */
 int tagtree_enter(struct tree_context* c, bool is_visible)
 {
+    logf( "%s", __func__);
+
     int rc = 0;
     struct tagentry *dptr;
     struct mp3entry *id3;
@@ -2076,6 +2112,7 @@ int tagtree_enter(struct tree_context* c, bool is_visible)
 /* Exits current database menu or table */
 void tagtree_exit(struct tree_context* c, bool is_visible)
 {
+    logf( "%s", __func__);
     if (is_visible) /* update selection history only for user-selected items */
     {
         if (c->selected_item != selected_item_history[c->dirlevel])
@@ -2472,6 +2509,7 @@ int tagtree_add_to_playlist(const char* playlist, bool new_playlist)
 
 static int tagtree_play_folder(struct tree_context* c)
 {
+    logf( "%s", __func__);
     int start_index = c->selected_item;
 
     if (playlist_create(NULL, NULL) < 0)
@@ -2502,6 +2540,7 @@ static int tagtree_play_folder(struct tree_context* c)
     }
 
     playlist_start(start_index, 0, 0);
+    loaded_entries_crc = tagtree_data_crc(c); /* save crc in case we return */
     return 0;
 }