Fix playback queue bug when "Insert Next" is used with multiple songs at once

After using “Insert Next” to insert multiple songs at once (e.g. an album from the database browser or folder from the file browser), subsequent Insert operations will incorrectly insert items after the first song of all items that were previously inserted, instead of after the last song of the previously inserted items.

A bug fix was originally written by Costas Calamvokis for the file browser only. I adopted the original fix and added code analogous to it so that it works from the database browser as well.

See FS#7898, FS#7363 or this forum post for more info:
https://forums.rockbox.org/index.php/topic,53741.0.html

Change-Id: Ie2718e136df0b340000f7a171e9e806cf23a27b4

2 files changed, 21 insertions, 25 deletions

diff --git a/apps/playlist.c b/apps/playlist.c
index c64fc229b5..3eb0949cc2 100644
--- a/apps/playlist.c
+++ b/apps/playlist.c
@@ -855,14 +855,14 @@ static int directory_search_callback(char* filename, void* context)
 
     if (insert_pos < 0)
         return -1;
-    
+
     (c->count)++;
-    
-    /* Make sure tracks are inserted in correct order if user requests
-       INSERT_FIRST */
-    if (c->position == PLAYLIST_INSERT_FIRST || c->position >= 0)
-        c->position = insert_pos + 1;
-    
+
+    /* After first INSERT_FIRST switch to INSERT so that all the
+    rest of the tracks get inserted one after the other */
+    if (c->position == PLAYLIST_INSERT_FIRST)
+        c->position = PLAYLIST_INSERT;
+
     if (((c->count)%PLAYLIST_DISPLAY_COUNT) == 0)
     {
         unsigned char* count_str;
@@ -3179,7 +3179,7 @@ int playlist_insert_playlist(struct playlist_info* playlist, const char *filenam
                 result = -1;
                 break;
             }
-            
+
             insert_pos = add_track_to_playlist(playlist, trackname, position,
                 queue, -1);
 
@@ -3189,13 +3189,13 @@ int playlist_insert_playlist(struct playlist_info* playlist, const char *filenam
                 break;
             }
 
-            /* Make sure tracks are inserted in correct order if user
-               requests INSERT_FIRST */
-            if (position == PLAYLIST_INSERT_FIRST || position >= 0)
-                position = insert_pos + 1;
+            /* After first INSERT_FIRST switch to INSERT so that all the
+            rest of the tracks get inserted one after the other */
+            if (position == PLAYLIST_INSERT_FIRST)
+                position = PLAYLIST_INSERT;
 
             count++;
-            
+
             if ((count%PLAYLIST_DISPLAY_COUNT) == 0)
             {
                 display_playlist_count(count, count_str, false);
diff --git a/apps/tagtree.c b/apps/tagtree.c
index f006baa581..97e0c67b62 100644
--- a/apps/tagtree.c
+++ b/apps/tagtree.c
@@ -2018,18 +2018,9 @@ static bool insert_all_playlist(struct tree_context *c, int position, bool queue
         }
     }
 
-    if (position == PLAYLIST_INSERT_FIRST)
-    {
-        from = c->filesindir - 1;
-        to = -1;
-        direction = -1;
-    }
-    else
-    {
-        from = 0;
-        to = c->filesindir;
-        direction = 1;
-    }
+    from = 0;
+    to = c->filesindir;
+    direction = 1;
 
     for (i = from; i != to; i += direction)
     {
@@ -2049,6 +2040,11 @@ static bool insert_all_playlist(struct tree_context *c, int position, bool queue
             break;
         }
         yield();
+
+        if (position == PLAYLIST_INSERT_FIRST)
+        {
+            position = PLAYLIST_INSERT;
+        }
     }
     playlist_sync(NULL);
     tagcache_search_finish(&tcs);