New upstream version 3.9

1 files changed, 341 insertions, 346 deletions

diff --git a/src/libaudcore/playlist.h b/src/libaudcore/playlist.h
index ef63a28..18292dc 100644
--- a/src/libaudcore/playlist.h
+++ b/src/libaudcore/playlist.h
@@ -1,6 +1,6 @@
 /*
  * playlist.h
- * Copyright 2010-2013 John Lindgren
+ * Copyright 2010-2017 John Lindgren
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -25,372 +25,367 @@
 #include <libaudcore/index.h>
 #include <libaudcore/tuple.h>
 
-namespace Playlist {
-
-/* The values which can be passed to the "playlist update" hook.  Selection
- * means that entries have been selected or unselected, or that entries have
- * been added to or removed from the queue.  Metadata means that new metadata
- * has been read for some entries, or that the title or filename of a playlist
- * has changed, and implies Selection.  Structure covers any other change, and
- * implies both Selection and Metadata. */
-enum UpdateLevel {
-    NoUpdate = 0,
-    Selection,
-    Metadata,
-    Structure
-};
+/*
+ * Persistent handle attached to a playlist.
+ * Follows the same playlist even if playlists are reordered.
+ * Does not prevent the playlist from being deleted (check exists()).
+ */
+class Playlist
+{
+public:
+    /* --- TYPES --- */
+
+    /* Opaque type which uniquely identifies a playlist */
+    struct ID;
+
+    /* The values which can be passed to the "playlist update" hook.  Selection
+     * means that entries have been selected or unselected, or that entries have
+     * been added to or removed from the queue.  Metadata means that new metadata
+     * has been read for some entries, or that the title or filename of a playlist
+     * has changed, and implies Selection.  Structure covers any other change, and
+     * implies both Selection and Metadata. */
+    enum UpdateLevel {
+        NoUpdate = 0,
+        Selection,
+        Metadata,
+        Structure
+    };
+
+    struct Update {
+        UpdateLevel level;   // type of update
+        int before;          // number of unaffected entries at playlist start
+        int after;           // number of unaffected entries at playlist end
+        bool queue_changed;  // true if entries have been added to/removed from queue
+    };
+
+    /* Preset sorting "schemes" */
+    enum SortType {
+        Path,            // entry's entire URI
+        Filename,        // base name (no folder path)
+        Title,
+        Album,
+        Artist,
+        AlbumArtist,
+        Date,            // release date (not modification time)
+        Genre,
+        Track,
+        FormattedTitle,
+        Length,
+        Comment,
+        n_sort_types
+    };
+
+    /* Possible behaviors for entry_{decoder, tuple}. */
+    enum GetMode {
+        NoWait,  // non-blocking call; returned tuple will be in Initial state if not yet scanned
+        Wait     // blocking call; returned tuple will be either Valid or Failed
+    };
+
+    /* Format descriptor returned by save_formats() */
+    struct SaveFormat {
+        String name;         // human-readable format name
+        Index<String> exts;  // supported filename extensions
+    };
+
+    typedef bool (* FilterFunc) (const char * filename, void * user);
+    typedef int (* StringCompareFunc) (const char * a, const char * b);
+    typedef int (* TupleCompareFunc) (const Tuple & a, const Tuple & b);
+
+    /* --- CONSTRUCTOR ETC. --- */
+
+    /* Default constructor; indicates "no playlist" */
+    constexpr Playlist () : m_id (nullptr) {}
+
+    bool operator== (const Playlist & b) const { return m_id == b.m_id; }
+    bool operator!= (const Playlist & b) const { return m_id != b.m_id; }
+
+    /* The number of the playlist in display order, starting from 0.
+     * Returns -1 if the playlist no longer exists. */
+    int index () const;
+
+    /* True if the playlist exists (i.e. has not been deleted). */
+    bool exists () const { return index () >= 0; }
+
+    /* --- CORE (STATIC) API --- */
+
+    /* Returns the number of playlists currently open (>= 1). */
+    static int n_playlists ();
+
+    /* Looks up a playlist by display order. */
+    static Playlist by_index (int at);
+
+    /* Adds a new playlist before the one numbered <at> (-1 = insert at end). */
+    static Playlist insert_playlist (int at);
+
+    /* Moves a contiguous block of <count> playlists starting with the one
+     * numbered <from> such that that playlist ends up at the position <to>. */
+    static void reorder_playlists (int from, int to, int count);
+
+    /* Returns the active (i.e. displayed) playlist. */
+    static Playlist active_playlist ();
+
+    /* Convenience function which adds a new playlist after the active one and
+     * then sets the new one as active.  Returns the new playlist. */
+    static Playlist new_playlist ();
+
+    /* Returns the currently playing playlist.  If no playlist is playing,
+     * returns Playlist(). */
+    static Playlist playing_playlist ();
+
+    /* Returns the number of a "blank" playlist.  The active playlist is
+     * returned if it has the default title and has no entries; otherwise, a new
+     * playlist is added and returned. */
+    static Playlist blank_playlist ();
+
+    /* Returns the number of the "temporary" playlist (which is no different
+     * from any other playlist except in name).  If the playlist does not exist,
+     * a "blank" playlist is renamed to become the temporary playlist. */
+    static Playlist temporary_playlist ();
+
+    /* Discards the metadata stored for all the entries that refer to a
+     * particular song file, in whatever playlist they appear, and starts
+     * reading it afresh from that file in the background. */
+    static void rescan_file (const char * filename);
+
+    /* --- CORE (NON-STATIC) API --- */
+
+    /* Gets/sets the filename associated with this playlist.
+     * (Audacious currently makes no use of the filename.) */
+    String get_filename () const;
+    void set_filename (const char * filename) const;
+
+    /* Gets/sets the title of the playlist. */
+    String get_title () const;
+    void set_title (const char * title) const;
+
+    /* Closes the playlist.
+     * The playlist is not saved, and no confirmation is presented to the user.
+     * When the last playlist is closed, a new one is added in its place.
+     * When the active playlist is closed, another is made active.
+     * When the playing playlist is closed, playback stops. */
+    void remove_playlist () const;
+
+    /* Makes this the active (i.e. displayed) playlist. */
+    void activate () const;
+
+    /* Starts playback of this playlist, unless it is empty.
+     * Resumes from the position last played if possible.
+     * If <paused> is true, starts playback in a paused state. */
+    void start_playback (bool paused = false) const;
+
+    /* Returns the number of entries (numbered from 0). */
+    int n_entries () const;
+
+    /* Adds a single song file, playlist file, or folder before the entry <at>.
+     * If <at> is negative or equal to the number of entries, the item is added
+     * after the last entry.  <tuple> may be null, in which case Audacious will
+     * attempt to read metadata from the song file.  If <play> is true,
+     * Audacious will begin playback of the items once they have been added.
+     *
+     * This function is asynchronous (the items are added in the background). */
+    void insert_entry (int at, const char * filename, Tuple && tuple, bool play) const;
+
+    /* Adds multiple song files, playlist files, or folders to a playlist. */
+    void insert_items (int at, Index<PlaylistAddItem> && items, bool play) const;
+
+    /* Similar to insert_items() but allows the caller to prevent some items
+     * from being added by returning false from the <filter> callback.  Useful
+     * for searching a folder and adding only new files to the playlist.  <user>
+     * is an opaque pointer passed to the callback. */
+    void insert_filtered (int at, Index<PlaylistAddItem> && items,
+     FilterFunc filter, void * user, bool play) const;
+
+    /* Removes entries from the playlist.  The playback position may be moved,
+     * or playback may be stopped (according to user preference). */
+    void remove_entries (int at, int number) const;
+    void remove_entry (int at) const { remove_entries (at, 1); }
+    void remove_all_entries () const { remove_entries (0, -1); }
+
+    /* Returns an entry's filename. */
+    String entry_filename (int entry) const;
+
+    /* Returns an entry's decoder plugin.  On error, or if the entry has not yet
+     * been scanned, returns nullptr according to <mode>.  An optional error
+     * message may be returned. */
+    PluginHandle * entry_decoder (int entry, GetMode mode = Wait, String * error = nullptr) const;
+
+    /* Returns an entry's metadata.  The state of the returned tuple may
+     * indicate that the entry has not yet been scanned, or an error occurred,
+     * according to <mode>.  An optional error message may be returned. */
+    Tuple entry_tuple (int entry, GetMode mode = Wait, String * error = nullptr) const;
+
+    /* Gets/sets the playing or last-played entry (-1 = no entry).
+     * Affects playback only if this playlist is currently playing.
+     * set_position(get_position()) restarts playback from 0:00.
+     * set_position(-1) stops playback. */
+    int get_position () const;
+    void set_position (int position) const;
+
+    /* Advances the playlist position to the next entry in playback order,
+     * taking current shuffle settings into account.  At the end of the
+     * playlist, wraps around to the beginning if <repeat> is true.  Returns
+     * true on success, false if playlist position was not changed. */
+    bool next_song (bool repeat) const;
+
+    /* Returns the playlist position to the previous entry in playback order.
+     * Does not support wrapping past the beginning of the playlist.  Returns
+     * true on success, false if playlist position was not changed. */
+    bool prev_song () const;
+
+    /* Gets/sets the entry which has keyboard focus (-1 = no entry). */
+    int get_focus () const;
+    void set_focus (int entry) const;
+
+    /* Gets/sets whether an entry is selected. */
+    bool entry_selected (int entry) const;
+    void select_entry (int entry, bool selected) const;
+
+    /* Returns the number of selected entries.
+     * An optional range of entries to examine may be specified. */
+    int n_selected (int at = 0, int number = -1) const;
+
+    /* Selects all (or none) of the entries in a playlist. */
+    void select_all (bool selected) const;
+
+    /* Moves a selected entry within a playlist by an offset of <distance>
+     * entries.  Other selected entries are gathered around it.  Returns the
+     * offset by which the entry was actually moved (which may be less than the
+     * requested offset. */
+    int shift_entries (int position, int distance) const;
+
+    /* Removes all selected entries. */
+    void remove_selected () const;
+
+    /* Sorts the entries in a playlist based on filename.  The callback function
+     * should return negative if the first filename comes before the second,
+     * positive if it comes after, or zero if the two are indistinguishable. */
+    void sort_by_filename (StringCompareFunc compare) const;
+
+    /* Sorts the entries in a playlist based on tuple.  May fail if metadata
+     * scanning is still in progress (or has been disabled). */
+    void sort_by_tuple (TupleCompareFunc compare) const;
+
+    /* Sorts the entries in a playlist based on formatted title string.  May fail if
+     * metadata scanning is still in progress (or has been disabled). */
+    void sort_by_title (StringCompareFunc compare) const;
+
+    /* Sorts only the selected entries in a playlist based on filename. */
+    void sort_selected_by_filename (StringCompareFunc compare) const;
+
+    /* Sorts only the selected entries in a playlist based on tuple.  May fail if
+     * metadata scanning is still in progress (or has been disabled). */
+    void sort_selected_by_tuple (TupleCompareFunc compare) const;
+
+    /* Sorts only the selected entries in a playlist based on formatted title
+     * string.  May fail if metadata scanning is still in progress (or has been
+     * disabled). */
+    void sort_selected_by_title (StringCompareFunc compare) const;
+
+    /* Reverses the order of the entries in a playlist. */
+    void reverse_order () const;
+
+    /* Reorders the entries in a playlist randomly. */
+    void randomize_order () const;
+
+    /* Reverses the order of the selected entries in a playlist. */
+    void reverse_selected () const;
+
+    /* Reorders the selected entries in a playlist randomly. */
+    void randomize_selected () const;
 
-struct Update {
-    UpdateLevel level;   // type of update
-    int before;          // number of unaffected entries at playlist start
-    int after;           // number of unaffected entries at playlist end
-    bool queue_changed;  // true if entries have been added to/removed from queue
-};
+    /* Discards the metadata stored for entries in a playlist and starts reading
+     * it fresh from the song files in the background. */
+    void rescan_all () const;
+    void rescan_selected () const;
 
-/* The values which can be passed to playlist_sort_by_scheme(),
- * playlist_sort_selected_by_scheme(), and
- * playlist_remove_duplicates_by_scheme().  PlaylistSort::Path means the entire
- * URI of a song file; PlaylistSort::Filename means the portion after the last
- * "/" (forward slash).  PlaylistSort::Date means the song's release date (not
- * the file's modification time). */
-enum SortType {
-    Path,
-    Filename,
-    Title,
-    Album,
-    Artist,
-    AlbumArtist,
-    Date,
-    Genre,
-    Track,
-    FormattedTitle,
-    Length,
-    n_sort_types
-};
+    /* Calculates the length in milliseconds of entries in a playlist.  Only
+     * takes into account entries for which metadata has already been read. */
+    int64_t total_length_ms () const;
+    int64_t selected_length_ms () const;
 
-/* Possible behaviors for playlist_entry_get_{decoder, tuple}. */
-enum GetMode {
-    NoWait,  // non-blocking call; returned tuple will be in Initial state if not yet scanned
-    Wait     // blocking call; returned tuple will be either Valid or Failed
-};
+    /* Returns the number of entries in a playlist queue. */
+    int n_queued () const;
 
-/* Format descriptor returned by playlist_save_formats() */
-struct SaveFormat {
-    String name;         // human-readable format name
-    Index<String> exts;  // supported filename extensions
-};
+    /* Adds an entry to the queue at <pos> (-1 = at end of queue).
+     * The same entry cannot be added to the queue more than once. */
+    void queue_insert (int pos, int entry) const;
+    void queue_insert_selected (int pos) const;
 
-} // namespace Playlist
-
-typedef bool (* PlaylistFilterFunc) (const char * filename, void * user);
-typedef int (* PlaylistStringCompareFunc) (const char * a, const char * b);
-typedef int (* PlaylistTupleCompareFunc) (const Tuple & a, const Tuple & b);
-
-/* --- PLAYLIST CORE API --- */
-
-/* Returns the number of playlists currently open.  There will always be at
- * least one playlist open.  The playlists are numbered starting from zero. */
-int aud_playlist_count ();
-
-/* Adds a new playlist before the one numbered <at>.  If <at> is -1 or equal to
- * the number of playlists, adds a new playlist after the last one. */
-void aud_playlist_insert (int at);
-
-/* Moves a contiguous block of <count> playlists starting with the one numbered
- * <from> such that that playlist ends up at the position <to>. */
-void aud_playlist_reorder (int from, int to, int count);
-
-/* Closes a playlist.  CAUTION: The playlist is not saved, and no confirmation
- * is presented to the user.  If <playlist> is the only playlist, a new playlist
- * is added.  If <playlist> is the active playlist, another playlist is marked
- * active.  If <playlist> is the currently playing playlist, playback is
- * stopped. */
-void aud_playlist_delete (int playlist);
-
-/* Returns a unique non-negative integer which can be used to identify a given
- * playlist even if its numbering changes (as when playlists are reordered).
- * On error, returns -1. */
-int aud_playlist_get_unique_id (int playlist);
-
-/* Returns the number of the playlist identified by a given integer ID as
- * returned by playlist_get_unique_id().  If the playlist no longer exists,
- * returns -1. */
-int aud_playlist_by_unique_id (int id);
-
-/* Sets the filename associated with a playlist.  (Audacious currently makes no
- * use of the filename.) */
-void aud_playlist_set_filename (int playlist, const char * filename);
-
-/* Returns the filename associated with a playlist. */
-String aud_playlist_get_filename (int playlist);
-
-/* Sets the title associated with a playlist. */
-void aud_playlist_set_title (int playlist, const char * title);
-
-/* Returns the title associated with a playlist. */
-String aud_playlist_get_title (int playlist);
-
-/* Sets the active playlist.  This is the playlist that user interfaces will
- * show to the user. */
-void aud_playlist_set_active (int playlist);
-
-/* Returns the number of the active playlist. */
-int aud_playlist_get_active ();
-
-/* Convenience function which adds a new playlist after the active one and then
- * sets the new one as active.  Returns the number of the new playlist. */
-int aud_playlist_new ();
-
-/* Starts playback of a playlist, resuming from the position last played if
- * possible.  If <playlist> is -1 or if the requested playlist is empty, stops
- * playback.  If <paused> is true, starts playback in a paused state. */
-void aud_playlist_play (int playlist, bool paused = false);
-
-/* Returns the number of the currently playing playlist.  If no playlist is
- * playing, returns -1. */
-int aud_playlist_get_playing ();
-
-/* Returns the number of a "blank" playlist.  The active playlist is returned if
- * it has the default title and has no entries; otherwise, a new playlist is
- * added and returned. */
-int aud_playlist_get_blank ();
-
-/* Returns the number of the "temporary" playlist (which is no different from
- * any other playlist except in name).  If the playlist does not exist, a
- * "blank" playlist is obtained from playlist_get_blank() and is renamed to
- * become the temporary playlist. */
-int aud_playlist_get_temporary ();
-
-/* Returns the number of entries in a playlist.  The entries are numbered
- * starting from zero. */
-int aud_playlist_entry_count (int playlist);
-
-/* Adds a song file, playlist file, or folder to a playlist before the entry
- * numbered <at>.  If <at> is negative or equal to the number of entries, the
- * item is added after the last entry.  <tuple> may be nullptr, in which case
- * Audacious will attempt to read metadata from the song file.  If <play> is
- * true, Audacious will begin playback of the items once they have been
- * added.
- *
- * Because adding items to the playlist can be a slow process, this function may
- * return before the process is complete.  Hence, the caller must not assume
- * that there will be new entries in the playlist immediately. */
-void aud_playlist_entry_insert (int playlist, int at, const char * filename,
- Tuple && tuple, bool play);
-
-/* Similar to playlist_entry_insert, adds multiple song files, playlist files,
- * or folders to a playlist. */
-void aud_playlist_entry_insert_batch (int playlist, int at,
- Index<PlaylistAddItem> && items, bool play);
-
-/* Similar to playlist_entry_insert_batch, but allows the caller to prevent some
- * items from being added by returning false from the <filter> callback.  Useful
- * for searching a folder and adding only new files to the playlist.  <user> is
- * an additional, untyped pointer passed to the callback. */
-void aud_playlist_entry_insert_filtered (int playlist, int at,
- Index<PlaylistAddItem> && items, PlaylistFilterFunc filter, void * user,
- bool play);
-
-/* Removes a contiguous block of <number> entries starting from the one numbered
- * <at> from a playlist.  If necessary, the playback position is moved elsewhere
- * in the playlist and playback is restarted (or stopped). */
-void aud_playlist_entry_delete (int playlist, int at, int number);
-
-/* Returns the filename of an entry. */
-String aud_playlist_entry_get_filename (int playlist, int entry);
-
-/* Returns a handle to the decoder plugin associated with an entry.  On error,
- * or if the entry has not yet been scanned, returns nullptr according to
- * <mode>.  On error, an error message is optionally returned. */
-PluginHandle * aud_playlist_entry_get_decoder (int playlist, int entry,
- Playlist::GetMode mode = Playlist::Wait, String * error = nullptr);
-
-/* Returns the tuple associated with an entry.  The state of the returned tuple
- * may indicate that the entry has not yet been scanned, or an error occurred,
- * according to <mode>.  On error, an error message is optionally returned. */
-Tuple aud_playlist_entry_get_tuple (int playlist, int entry,
- Playlist::GetMode mode = Playlist::Wait, String * error = nullptr);
-
-/* Moves the playback position to the beginning of the entry at <position>.  If
- * <position> is -1, unsets the playback position.  If <playlist> is the
- * currently playing playlist, playback is restarted (or stopped). */
-void aud_playlist_set_position (int playlist, int position);
-
-/* Returns the playback position, or -1 if it is not set.  Note that the
- * position may be set even if <playlist> is not currently playing. */
-int aud_playlist_get_position (int playlist);
-
-/* Sets the entry which has keyboard focus (-1 means no entry). */
-void aud_playlist_set_focus (int playlist, int entry);
-
-/* Gets the entry which has keyboard focus (-1 means no entry). */
-int aud_playlist_get_focus (int playlist);
-
-/* Sets whether an entry is selected. */
-void aud_playlist_entry_set_selected (int playlist, int entry, bool selected);
-
-/* Returns whether an entry is selected. */
-bool aud_playlist_entry_get_selected (int playlist, int entry);
-
-/* Returns the number of selected entries in a playlist. */
-int aud_playlist_selected_count (int playlist);
-
-/* Selects all (or none) of the entries in a playlist. */
-void aud_playlist_select_all (int playlist, bool selected);
-
-/* Moves a selected entry within a playlist by an offset of <distance> entries.
- * Other selected entries are gathered around it.  Returns the offset by which
- * the entry was actually moved, which may be less in absolute value than the
- * requested offset. */
-int aud_playlist_shift (int playlist, int position, int distance);
-
-/* Removes the selected entries from a playlist.  If necessary, the playback
- * position is moved elsewhere in the playlist and playback is restarted (or
- * stopped). */
-void aud_playlist_delete_selected (int playlist);
-
-/* Sorts the entries in a playlist based on filename.  The callback function
- * should return negative if the first filename comes before the second,
- * positive if it comes after, or zero if the two are indistinguishable. */
-void aud_playlist_sort_by_filename (int playlist, PlaylistStringCompareFunc compare);
-
-/* Sorts the entries in a playlist based on tuple.  May fail if metadata
- * scanning is still in progress (or has been disabled). */
-void aud_playlist_sort_by_tuple (int playlist, PlaylistTupleCompareFunc compare);
-
-/* Sorts the entries in a playlist based on formatted title string.  May fail if
- * metadata scanning is still in progress (or has been disabled). */
-void aud_playlist_sort_by_title (int playlist, PlaylistStringCompareFunc compare);
-
-/* Sorts only the selected entries in a playlist based on filename. */
-void aud_playlist_sort_selected_by_filename (int playlist, PlaylistStringCompareFunc compare);
-
-/* Sorts only the selected entries in a playlist based on tuple.  May fail if
- * metadata scanning is still in progress (or has been disabled). */
-void aud_playlist_sort_selected_by_tuple (int playlist, PlaylistTupleCompareFunc compare);
-
-/* Sorts only the selected entries in a playlist based on formatted title
- * string.  May fail if metadata scanning is still in progress (or has been
- * disabled). */
-void aud_playlist_sort_selected_by_title (int playlist, PlaylistStringCompareFunc compare);
-
-/* Reverses the order of the entries in a playlist. */
-void aud_playlist_reverse (int playlist);
-
-/* Reorders the entries in a playlist randomly. */
-void aud_playlist_randomize (int playlist);
-
-/* Reverses the order of the selected entries in a playlist. */
-void aud_playlist_reverse_selected (int playlist);
-
-/* Reorders the selected entries in a playlist randomly. */
-void aud_playlist_randomize_selected (int playlist);
-
-/* Discards the metadata stored for all the entries in a playlist and starts
- * reading it afresh from the song files in the background. */
-void aud_playlist_rescan (int playlist);
+    /* Returns the entry at the given queue position. */
+    int queue_get_entry (int pos) const;
+
+    /* Returns the queue position of the given entry (-1 if not queued). */
+    int queue_find_entry (int entry) const;
 
-/* Like playlist_rescan, but applies only to the selected entries in a playlist. */
-void aud_playlist_rescan_selected (int playlist);
-
-/* Discards the metadata stored for all the entries that refer to a particular
- * song file, in whatever playlist they appear, and starts reading it afresh
- * from that file in the background. */
-void aud_playlist_rescan_file (const char * filename);
+    /* Removes entries from the queue. */
+    void queue_remove (int pos, int number = 1) const;
+    void queue_remove_all () const { queue_remove (0, -1); }
 
-/* Calculates the total length in milliseconds of all the entries in a playlist.
- * Only takes into account entries for which metadata has already been read. */
-int64_t aud_playlist_get_total_length (int playlist);
+    /* Removes the selected entries in a playlist from the queue, if they are in it. */
+    void queue_remove_selected () const;
 
-/* Calculates the total length in milliseconds of only the selected entries in a
- * playlist.  Only takes into account entries for which metadata has already
- * been read. */
-int64_t aud_playlist_get_selected_length (int playlist);
+    /* Returns true if a "playlist update" hook call is pending.
+     * A running hook call is not considered pending. */
+    bool update_pending () const;
+    static bool update_pending_any ();
 
-/* Returns the number of entries in a playlist queue.  The entries are numbered
- * starting from zero, lower numbers being played first. */
-int aud_playlist_queue_count (int playlist);
+    /* May be called within the "playlist update" hook to determine the update
+     * level and number of entries changed in a playlist. */
+    Update update_detail () const;
 
-/* Adds an entry to a playlist's queue before the entry numbered <at> in the
- * queue.  If <at> is negative or equal to the number of entries in the queue,
- * adds the entry after the last one in the queue.  The same entry cannot be
- * added to the queue more than once. */
-void aud_playlist_queue_insert (int playlist, int at, int entry);
+    /* Returns true if entries are being added in the background. */
+    bool add_in_progress () const;
+    static bool add_in_progress_any ();
 
-/* Adds the selected entries in a playlist to the queue, if they are not already
- * in it. */
-void aud_playlist_queue_insert_selected (int playlist, int at);
+    /* Returns true if entries are being scanned in the background. */
+    bool scan_in_progress () const;
+    static bool scan_in_progress_any ();
 
-/* Returns the position in the playlist of the entry at a given position in the
- * queue. */
-int aud_playlist_queue_get_entry (int playlist, int at);
+    /* --- UTILITY API --- */
 
-/* Returns the position in the queue of the entry at a given position in the
- * playlist.  If it is not in the queue, returns -1. */
-int aud_playlist_queue_find_entry (int playlist, int entry);
+    /* Sorts entries according to a preset scheme. */
+    void sort_entries (SortType scheme) const;
+    void sort_selected (SortType scheme) const;
 
-/* Removes a contiguous block of <number> entries starting with the one numbered
- * <at> from the queue. */
-void aud_playlist_queue_delete (int playlist, int at, int number);
-
-/* Removes the selected entries in a playlist from the queue, if they are in it. */
-void aud_playlist_queue_delete_selected (int playlist);
-
-/* Returns true if a "playlist update" hook call is pending for the given
- * playlist (or for any playlist, if <playlist> is -1).  If called from within
- * the hook, the current hook call is not considered pending. */
-bool aud_playlist_update_pending (int playlist = -1);
-
-/* May be called within the "playlist update" hook to determine the update level
- * and number of entries changed in a playlist. */
-Playlist::Update aud_playlist_update_detail (int playlist);
-
-/* Returns true if entries are being added to a playlist in the background.
- * If <playlist> is -1, checks all playlists. */
-bool aud_playlist_add_in_progress (int playlist);
+    /* Removes duplicate entries according to a preset scheme.
+     * The current implementation also sorts the playlist. */
+    void remove_duplicates (SortType scheme) const;
 
-/* Returns true if entries in a playlist are being scanned for metadata in
- * the background.  If <playlist> is -1, checks all playlists. */
-bool aud_playlist_scan_in_progress (int playlist);
+    /* Removes all entries referring to inaccessible files in a playlist. */
+    void remove_unavailable () const;
 
-/* --- PLAYLIST UTILITY API --- */
+    /* Selects entries by matching regular expressions.
+     * Example: To select all titles starting with the letter "A",
+     * create a blank tuple and set its title field to "^A". */
+    void select_by_patterns (const Tuple & patterns) const;
 
-/* Sorts the entries in a playlist according to one of the schemes listed in
- * playlist.h. */
-void aud_playlist_sort_by_scheme (int playlist, Playlist::SortType scheme);
+    /* Saves metadata for the selected entries to an internal cache.
+     * This will speed up adding those entries to another playlist. */
+    void cache_selected () const;
 
-/* Sorts only the selected entries in a playlist according to one of those
- * schemes. */
-void aud_playlist_sort_selected_by_scheme (int playlist, Playlist::SortType scheme);
+    /* Saves the entries in a playlist to a playlist file.
+     * The format of the file is determined from the file extension.
+     * <mode> specifies whether to wait for metadata scanning to complete.
+     * Returns true on success. */
+    bool save_to_file (const char * filename, GetMode mode) const;
 
-/* Removes duplicate entries in a playlist according to one of those schemes.
- * As currently implemented, first sorts the playlist. */
-void aud_playlist_remove_duplicates_by_scheme (int playlist, Playlist::SortType scheme);
+    /* Checks a filename for an extension matching a known playlist format. */
+    static bool filename_is_playlist (const char * filename);
 
-/* Removes all entries referring to unavailable files in a playlist.  ("Remove
- * failed" is something of a misnomer for the current behavior.) */
-void aud_playlist_remove_failed (int playlist);
+    /* Generates a list of the currently supported formats for saving playlists.
+     * The list should not be cached since it may change as plugins are enabled or
+     * disabled. */
+    static Index<SaveFormat> save_formats ();
 
-/* Selects all the entries in a playlist that match regular expressions stored
- * in the fields of a tuple.  Does not free the memory used by the tuple.
- * Example: To select all the songs whose title starts with the letter "A",
- * create a blank tuple and set its title field to "^A". */
-void aud_playlist_select_by_patterns (int playlist, const Tuple & patterns);
+    /* --- IMPLEMENTATION --- */
 
-/* Saves metadata for the selected entries in a playlist to an internal cache,
- * which is used to speed up adding these entries to another playlist. */
-void aud_playlist_cache_selected (int playlist);
-
-/* Returns true if <filename> refers to a playlist file. */
-bool aud_filename_is_playlist (const char * filename);
-
-/* Saves the entries in a playlist to a playlist file.  The format of the file
- * is determined from the file extension.  Returns true on success. */
-bool aud_playlist_save (int playlist, const char * filename, Playlist::GetMode mode);
-
-/* Generates a list of the currently supported formats for saving playlists.
- * The list should not be cached since it may change as plugins are enabled or
- * disabled. */
-Index<Playlist::SaveFormat> aud_playlist_save_formats ();
+private:
+    ID * m_id;
+
+    explicit constexpr Playlist (ID * id) :
+        m_id (id) {}
+
+    friend class PlaylistEx;
+};
 
 #endif