playlist: assign unique id to playlist items

Playlist items are intended to be handled by index (with lock held) or
by instance (vlc_playlist_item_t *).

Some modules, like http, require to reference playlist items "remotely".
To simplify their implementation, assign an id, unique within a playlist
instance, to every items.

Signed-off-by: Thomas Guillem <thomas@gllm.fr>

include/vlc_playlist.h

@@ -316,6 +316,12 @@ vlc_playlist_item_Release(vlc_playlist_item_t *);
 VLC_API input_item_t *
 vlc_playlist_item_GetMedia(vlc_playlist_item_t *);
 
+/**
+ * Return a unique id for the playlist item instance.
+ */
+VLC_API uint64_t
+vlc_playlist_item_GetId(vlc_playlist_item_t *);
+
 /* Playlist */
 
 /**
@@ -655,6 +661,16 @@ vlc_playlist_IndexOf(vlc_playlist_t *playlist, const vlc_playlist_item_t *item);
 VLC_API ssize_t
 vlc_playlist_IndexOfMedia(vlc_playlist_t *playlist, const input_item_t *media);
 
+/**
+ * Return the index of a given item id.
+ *
+ * \param playlist the playlist, locked
+ * \param id       the id to locate
+ * \return the index of the playlist item having the id (-1 if not found)
+ */
+VLC_API ssize_t
+vlc_playlist_IndexOfId(vlc_playlist_t *playlist, uint64_t id);
+
 /**
  * Return the playback "repeat" mode.
  *

src/libvlccore.sym

@@ -936,6 +936,7 @@ vlc_player_vout_Snapshot
 vlc_playlist_item_Hold
 vlc_playlist_item_Release
 vlc_playlist_item_GetMedia
+vlc_playlist_item_GetId
 vlc_playlist_New
 vlc_playlist_Delete
 vlc_playlist_Lock
@@ -955,6 +956,7 @@ vlc_playlist_Shuffle
 vlc_playlist_Sort
 vlc_playlist_IndexOf
 vlc_playlist_IndexOfMedia
+vlc_playlist_IndexOfId
 vlc_playlist_GetPlaybackRepeat
 vlc_playlist_GetPlaybackOrder
 vlc_playlist_SetPlaybackRepeat

src/playlist/content.c

@@ -205,6 +205,18 @@ vlc_playlist_IndexOfMedia(vlc_playlist_t *playlist, const input_item_t *media)
     return -1;
 }
 
+ssize_t
+vlc_playlist_IndexOfId(vlc_playlist_t *playlist, uint64_t id)
+{
+    vlc_playlist_AssertLocked(playlist);
+
+    playlist_item_vector_t *items = &playlist->items;
+    for (size_t i = 0; i < items->size; ++i)
+        if (items->data[i]->id == id)
+            return i;
+    return -1;
+}
+
 void
 vlc_playlist_Clear(vlc_playlist_t *playlist)
 {
@@ -218,13 +230,15 @@ vlc_playlist_Clear(vlc_playlist_t *playlist)
 }
 
 static int
-vlc_playlist_MediaToItems(input_item_t *const media[], size_t count,
-                          vlc_playlist_item_t *items[])
+vlc_playlist_MediaToItems(vlc_playlist_t *playlist, input_item_t *const media[],
+                          size_t count, vlc_playlist_item_t *items[])
 {
+    vlc_playlist_AssertLocked(playlist);
     size_t i;
     for (i = 0; i < count; ++i)
     {
-        items[i] = vlc_playlist_item_New(media[i]);
+        uint64_t id = playlist->idgen++;
+        items[i] = vlc_playlist_item_New(media[i], id);
         if (unlikely(!items[i]))
             break;
     }
@@ -250,7 +264,7 @@ vlc_playlist_Insert(vlc_playlist_t *playlist, size_t index,
         return VLC_ENOMEM;
 
     /* create playlist items in place */
-    int ret = vlc_playlist_MediaToItems(media, count,
+    int ret = vlc_playlist_MediaToItems(playlist, media, count,
                                         &playlist->items.data[index]);
     if (ret != VLC_SUCCESS)
     {
@@ -307,7 +321,8 @@ vlc_playlist_Replace(vlc_playlist_t *playlist, size_t index,
     vlc_playlist_AssertLocked(playlist);
     assert(index < playlist->items.size);
 
-    vlc_playlist_item_t *item = vlc_playlist_item_New(media);
+    uint64_t id = playlist->idgen++;
+    vlc_playlist_item_t *item = vlc_playlist_item_New(media, id);
     if (!item)
         return VLC_ENOMEM;
 
@@ -347,7 +362,7 @@ vlc_playlist_Expand(vlc_playlist_t *playlist, size_t index,
                 return VLC_ENOMEM;
 
             /* create playlist items in place */
-            ret = vlc_playlist_MediaToItems(&media[1], count - 1,
+            ret = vlc_playlist_MediaToItems(playlist, &media[1], count - 1,
                                             &playlist->items.data[index + 1]);
             if (ret != VLC_SUCCESS)
             {

src/playlist/item.c

@@ -28,13 +28,14 @@
 #include <vlc_input_item.h>
 
 vlc_playlist_item_t *
-vlc_playlist_item_New(input_item_t *media)
+vlc_playlist_item_New(input_item_t *media, uint64_t id)
 {
     vlc_playlist_item_t *item = malloc(sizeof(*item));
     if (unlikely(!item))
         return NULL;
 
     vlc_atomic_rc_init(&item->rc);
+    item->id = id;
     item->media = media;
     input_item_Hold(media);
     return item;
@@ -61,3 +62,9 @@ vlc_playlist_item_GetMedia(vlc_playlist_item_t *item)
 {
     return item->media;
 }
+
+uint64_t
+vlc_playlist_item_GetId(vlc_playlist_item_t *item)
+{
+    return item->id;
+}

src/playlist/item.h

@@ -29,11 +29,12 @@ typedef struct input_item_t input_item_t;
 struct vlc_playlist_item
 {
     input_item_t *media;
+    uint64_t id;
     vlc_atomic_rc_t rc;
 };
 
 /* _New() is private, it is called when inserting new media in the playlist */
 vlc_playlist_item_t *
-vlc_playlist_item_New(input_item_t *media);
+vlc_playlist_item_New(input_item_t *media, uint64_t id);
 
 #endif

src/playlist/playlist.c

@@ -52,6 +52,7 @@ vlc_playlist_New(vlc_object_t *parent)
     vlc_list_init(&playlist->listeners);
     playlist->repeat = VLC_PLAYLIST_PLAYBACK_REPEAT_NONE;
     playlist->order = VLC_PLAYLIST_PLAYBACK_ORDER_NORMAL;
+    playlist->idgen = 0;
 
     return playlist;
 }

src/playlist/playlist.h

@@ -57,6 +57,7 @@ struct vlc_playlist
     struct vlc_list listeners; /**< list of vlc_playlist_listener_id.node */
     enum vlc_playlist_playback_repeat repeat;
     enum vlc_playlist_playback_order order;
+    uint64_t idgen;
 };
 
 static inline void

src/playlist/preparse.c

@@ -32,14 +32,17 @@
 typedef struct VLC_VECTOR(input_item_t *) media_vector_t;
 
 static void
-vlc_playlist_CollectChildren(media_vector_t *dest, input_item_node_t *node)
+vlc_playlist_CollectChildren(vlc_playlist_t *playlist,
+                             media_vector_t *dest,
+                             input_item_node_t *node)
 {
+    vlc_playlist_AssertLocked(playlist);
     for (int i = 0; i < node->i_children; ++i)
     {
         input_item_node_t *child = node->pp_children[i];
         input_item_t *media = child->p_item;
         vlc_vector_push(dest, media);
-        vlc_playlist_CollectChildren(dest, child);
+        vlc_playlist_CollectChildren(playlist, dest, child);
     }
 }
 
@@ -50,7 +53,7 @@ vlc_playlist_ExpandItem(vlc_playlist_t *playlist, size_t index,
     vlc_playlist_AssertLocked(playlist);
 
     media_vector_t flatten = VLC_VECTOR_INITIALIZER;
-    vlc_playlist_CollectChildren(&flatten, node);
+    vlc_playlist_CollectChildren(playlist, &flatten, node);
 
     int ret = vlc_playlist_Expand(playlist, index, flatten.data, flatten.size);
     vlc_vector_destroy(&flatten);

src/playlist/test.c

@@ -1504,7 +1504,7 @@ test_request_remove_adapt(void)
             vlc_playlist_AddListener(playlist, &cbs, &ctx, false);
     assert(listener);
 
-    vlc_playlist_item_t *dummy = vlc_playlist_item_New(media[10]);
+    vlc_playlist_item_t *dummy = vlc_playlist_item_New(media[10], 0);
     assert(dummy);
 
     /* remove items in a wrong order at wrong position, as if the playlist had
@@ -1702,7 +1702,7 @@ test_request_move_adapt(void)
             vlc_playlist_AddListener(playlist, &cbs, &ctx, false);
     assert(listener);
 
-    vlc_playlist_item_t *dummy = vlc_playlist_item_New(media[15]);
+    vlc_playlist_item_t *dummy = vlc_playlist_item_New(media[15], 0);
     assert(dummy);
 
     /* move items in a wrong order at wrong position, as if the playlist had