[vlc-devel] [PATCH 3/3] core: playlist: keep current item on expand

[Romain Vimont]

When an item is expanded (e.g. due to preparsing), it is replaced by its
(flatten) subitems.

The previous implementation first removed the item, then inserted its
subitems. As a consequence of the removal, the current index was reset
and the player was stopped.

Since we don't want to stop the player on item expansion, instead,
replace the item by its first subitem (if any), then insert the
remaining subitems.
---
 src/playlist/content.c | 74 ++++++++++++++++++++++++++++++++++++++++--
 src/playlist/test.c    |  7 ++++
 2 files changed, 79 insertions(+), 2 deletions(-)

diff --git a/src/playlist/content.c b/src/playlist/content.c
index 312db31202..43b3800d9f 100644
--- a/src/playlist/content.c
+++ b/src/playlist/content.c
@@ -155,6 +155,20 @@ vlc_playlist_ItemsRemoved(vlc_playlist_t *playlist, size_t index, size_t count)
     return current_media_changed;
 }
 
+static void
+vlc_playlist_ItemReplaced(vlc_playlist_t *playlist, size_t index)
+{
+    struct vlc_playlist_state state;
+    vlc_playlist_state_Save(playlist, &state);
+
+    playlist->has_prev = vlc_playlist_ComputeHasPrev(playlist);
+    playlist->has_next = vlc_playlist_ComputeHasNext(playlist);
+
+    vlc_playlist_Notify(playlist, on_items_updated, index,
+                        &playlist->items.data[index], 1);
+    vlc_playlist_state_NotifyChanges(playlist, &state);
+}
+
 size_t
 vlc_playlist_Count(vlc_playlist_t *playlist)
 {
@@ -286,6 +300,31 @@ vlc_playlist_Remove(vlc_playlist_t *playlist, size_t index, size_t count)
         vlc_player_InvalidateNextMedia(playlist->player);
 }
 
+static int
+vlc_playlist_Replace(vlc_playlist_t *playlist, size_t index,
+                     input_item_t *media)
+{
+    vlc_playlist_AssertLocked(playlist);
+    assert(index < playlist->items.size);
+
+    vlc_playlist_item_t *item = vlc_playlist_item_New(media);
+    if (!item)
+        return VLC_ENOMEM;
+
+    if (playlist->order == VLC_PLAYLIST_PLAYBACK_ORDER_RANDOM)
+    {
+        randomizer_Remove(&playlist->randomizer,
+                          &playlist->items.data[index], 1);
+        randomizer_Add(&playlist->randomizer, &item, 1);
+    }
+
+    vlc_playlist_item_Release(playlist->items.data[index]);
+    playlist->items.data[index] = item;
+
+    vlc_playlist_ItemReplaced(playlist, index);
+    return VLC_SUCCESS;
+}
+
 int
 vlc_playlist_Expand(vlc_playlist_t *playlist, size_t index,
                     input_item_t *const media[], size_t count)
@@ -293,6 +332,37 @@ vlc_playlist_Expand(vlc_playlist_t *playlist, size_t index,
     vlc_playlist_AssertLocked(playlist);
     assert(index < playlist->items.size);
 
-    vlc_playlist_RemoveOne(playlist, index);
-    return vlc_playlist_Insert(playlist, index, media, count);
+    if (count == 0)
+        vlc_playlist_RemoveOne(playlist, index);
+    else
+    {
+        int ret = vlc_playlist_Replace(playlist, index, media[0]);
+        if (ret != VLC_SUCCESS)
+            return ret;
+
+        if (count > 1)
+        {
+            /* make space in the vector */
+            if (!vlc_vector_insert_hole(&playlist->items, index + 1, count - 1))
+                return VLC_ENOMEM;
+
+            /* create playlist items in place */
+            ret = vlc_playlist_MediaToItems(&media[1], count - 1,
+                                            &playlist->items.data[index + 1]);
+            if (ret != VLC_SUCCESS)
+            {
+                /* we were optimistic, it failed, restore the vector state */
+                vlc_vector_remove_slice(&playlist->items, index + 1, count - 1);
+                return ret;
+            }
+            vlc_playlist_ItemsInserted(playlist, index + 1, count - 1);
+        }
+
+        if ((ssize_t) index == playlist->current)
+            vlc_playlist_SetCurrentMedia(playlist, playlist->current);
+        else
+            vlc_player_InvalidateNextMedia(playlist->player);
+    }
+
+    return VLC_SUCCESS;
 }
diff --git a/src/playlist/test.c b/src/playlist/test.c
index b24a95adb7..df0eb6fe0e 100644
--- a/src/playlist/test.c
+++ b/src/playlist/test.c
@@ -285,6 +285,10 @@ test_expand_item(void)
         assert(node);
     }
 
+    playlist->current = 8;
+    playlist->has_prev = true;
+    playlist->has_next = true;
+
     ret = vlc_playlist_ExpandItem(playlist, 8, root);
     assert(ret == VLC_SUCCESS);
     assert(vlc_playlist_Count(playlist) == 15);
@@ -301,6 +305,9 @@ test_expand_item(void)
 
     EXPECT_AT(14, 9);
 
+    /* item 8 will be replaced, the current must stay the same */
+    assert(playlist->current == 8);
+
     input_item_node_Delete(root);
     DestroyMediaArray(media, 16);
     vlc_playlist_Delete(playlist);
-- 
2.20.0.rc2