iPod database reading/writing

iPod database reading/writing — Functions to read, write, and create an iPod database

Synopsis




                    Itdb_iTunesDB;
enum                ItdbFileError;
Itdb_iTunesDB*      itdb_new                            (void);
void                itdb_free                           (Itdb_iTunesDB *itdb);
Itdb_iTunesDB*      itdb_parse                          (const gchar *mp,
                                                         GError **error);
gboolean            itdb_write                          (Itdb_iTunesDB *itdb,
                                                         GError **error);
void                itdb_set_mountpoint                 (Itdb_iTunesDB *itdb,
                                                         const gchar *mp);
const gchar*        itdb_get_mountpoint                 (Itdb_iTunesDB *itdb);
guint32             itdb_tracks_number                  (Itdb_iTunesDB *itdb);
guint32             itdb_tracks_number_nontransferred   (Itdb_iTunesDB *itdb);
guint32             itdb_playlists_number               (Itdb_iTunesDB *itdb);
void                (*ItdbUserDataDestroyFunc)          (gpointer userdata);
gpointer            (*ItdbUserDataDuplicateFunc)        (gpointer userdata);

Description

These functions are for reading, writing, creating, and deleting an iPod database and getting the total number of tracks and playlists.

Overview of using an iPod database:

itdb_parse(): read the iTunesDB and ArtworkDB

itdb_write(): write the iTunesDB and ArtworkDB

itdb_parse() will return a Itdb_iTunesDB structure with GLists containing all tracks the playlists in the database. Each track is represented by an Itdb_Track. Each playlist is represented by an Itdb_Playlist. See the Tracks and Playlists sections for details on tracks and playlists, respectively.

Each Itdb_Playlist has a GList called members which contains all of the tracks in the playlist. Tracks referenced in a playlist must also be present in the tracks GList of the Itdb_iTunesDB.

The iPod must contain one master playlist (MPL) containing all tracks accessible on the iPod through the Music->Tracks/Albums/Artists/etc. menu. In addition to the MPL there can be a number of normal playlists accessible through the Music->Playlists menu on the iPod. Tracks that are a member of one of these normal playlists must also be a member of the MPL.

The Podcasts playlist is just another playlist with some internal flags set differently. Tracks in the Podcasts playlist are not normally members of the MPL (so on the iPod they will only show up under the Podcasts menu). All tracks referenced must be in the tracks GList of the Itdb_iTunesDB, however.

Each track may have a thumbnail associated with it. You can retrieve a GdkPixmap of the thumbnail using itdb_artwork_get_pixbuf(). A thumbnail can be added with itdb_track_set_thumbnails(). A thumbnail can be removed with itdb_track_remove_thumbnails(). Please see the Artwork section for more details on artwork related functions and structures.

Note

Be aware that iTunes additionally stores the artwork as tags in the original music file. That's also from where the data is read when artwork is displayed in iTunes, and there can be more than one piece of artwork. libgpod does not store the artwork as tags in the original music file. As a consequence, if iTunes attempts to access the artwork, it will find none, and remove libgpod's artwork. Luckily, iTunes will only attempt to access the artwork if you select a track in iTunes. To work around this, gtkpod keeps a list of the original filename of all artwork and silently adds the thumbnails if they were 'lost'. Your application might want to do something similar, or you can supply patches for (optionally!) adding tags to the original music files.

The Itdb_iTunesDB, Itdb_Playlist and Itdb_Track structures each have userdata and usertype fields that can be used by the application to store additional application-specific data. If userdata is a pointer to an external structure, you can supply a ItdbUserDataDuplicateFunc and a ItdbUserDataDestroyFunc so that this data can be duplicated or freed automatically with a call to the library _duplicate()/_free() functions.

Details

Itdb_iTunesDB

typedef struct {
    GList *tracks;
    GList *playlists;
    gchar *filename;
    Itdb_Device *device;
    guint32 version;
    guint64 id;
    /* reserved for future use */
    gint32 reserved_int1;
    gint32 reserved_int2;
    gpointer reserved1;
    gpointer reserved2;
    /* below is for use by application */
    guint64 usertype;
    gpointer userdata;
    /* functions called to duplicate/free userdata */
    ItdbUserDataDuplicateFunc userdata_duplicate;
    ItdbUserDataDestroyFunc userdata_destroy;
} Itdb_iTunesDB;

Structure representing an iTunes database

GList *tracks;

 A list of tracks in the database (Itdb_Track)

GList *playlists;

 A list of playlists in the database (Itdb_Playlist)

gchar *filename;

 The filename of the iTunesDB

Itdb_Device *device;

 iPod device info (Itdb_Device)

guint32 version;

 The version number of the iTunesDB

guint64 id;

 A 64 bit id value for the iTunesDB

gint32 reserved_int1;

 Reserved for future use

gint32 reserved_int2;

 Reserved for future use

gpointer reserved1;

 Reserved for future use

gpointer reserved2;

 Reserved for future use

guint64 usertype;

 For use by application

gpointer userdata;

 For use by application

ItdbUserDataDuplicateFunc userdata_duplicate;

 A function to duplicate userdata

ItdbUserDataDestroyFunc userdata_destroy;

 A function to free userdata

enum ItdbFileError

typedef enum
{
    ITDB_FILE_ERROR_SEEK,
    ITDB_FILE_ERROR_CORRUPT,
    ITDB_FILE_ERROR_NOTFOUND,
    ITDB_FILE_ERROR_RENAME,
    ITDB_FILE_ERROR_ITDB_CORRUPT
} ItdbFileError;

Error codes for iTunesDB file

ITDB_FILE_ERROR_SEEK

 file corrupt: illegal seek occured

ITDB_FILE_ERROR_CORRUPT

 file corrupt

ITDB_FILE_ERROR_NOTFOUND

 file not found

ITDB_FILE_ERROR_RENAME

 file could not be renamed

ITDB_FILE_ERROR_ITDB_CORRUPT

 iTunesDB in memory corrupt

itdb_new ()

Itdb_iTunesDB*      itdb_new                            (void);

Creates a new Itdb_iTunesDB with the unknowns filled in to reasonable values.

Returns :

 a newly created Itdb_iTunesDB to be freed with itdb_free() when it's no longer needed

itdb_free ()

void                itdb_free                           (Itdb_iTunesDB *itdb);

Free the memory taken by itdb.

itdb :

 an Itdb_iTunesDB

itdb_parse ()

Itdb_iTunesDB*      itdb_parse                          (const gchar *mp,
                                                         GError **error);

Parse the Itdb_iTunesDB of the iPod located at mp

mp :

 mount point of the iPod (eg "/mnt/ipod") in local encoding

error :

 return location for a GError or NULL

Returns :

 a newly allocated Itdb_iTunesDB struct holding the tracks and the playlists present on the iPod at mp, NULL if mp isn't an iPod mount point. If non-NULL, the Itdb_iTunesDB is to be freed with itdb_free() when it's no longer needed

itdb_write ()

gboolean            itdb_write                          (Itdb_iTunesDB *itdb,
                                                         GError **error);

Write out an iTunesDB. It reassigns unique IDs to all tracks. An existing "Play Counts" file is renamed to "Play Counts.bak" if the export was successful. An existing "OTGPlaylistInfo" file is removed if the export was successful.

itdb :

 the Itdb_iTunesDB to write to disk

error :

 return location for a GError or NULL

Returns :

 TRUE on success, FALSE on error, in which case error is set accordingly.

itdb_set_mountpoint ()

void                itdb_set_mountpoint                 (Itdb_iTunesDB *itdb,
                                                         const gchar *mp);

Sets the mountpoint of itdb. Always use this function to set the mountpoint of an Itdb_iTunesDB as it will reset the number of available /iPod_Control/Music/F.. dirs. It doesn't attempt to parse an iPod database that may be present on the iPod at mp.

itdb :

 an Itdb_iTunesDB

mp :

 new mount point

Since 0.1.3

itdb_get_mountpoint ()

const gchar*        itdb_get_mountpoint                 (Itdb_iTunesDB *itdb);

Retrieve a reference to the mountpoint of itdb

itdb :

 an Itdb_iTunesDB

Returns :

 the itdb mountpoint, this string shouldn't be freed nor modified

Since 0.4.0

itdb_tracks_number ()

guint32             itdb_tracks_number                  (Itdb_iTunesDB *itdb);

Counts the number of tracks stored in itdb

itdb :

 an Itdb_iTunesDB

Returns :

 the number of tracks in itdb

itdb_tracks_number_nontransferred ()

guint32             itdb_tracks_number_nontransferred   (Itdb_iTunesDB *itdb);

Counts the number of non-transferred tracks in itdb

itdb :

 an Itdb_iTunesDB

Returns :

 the number of tracks in itdb that haven't been transferred to the iPod yet (ie the number of Itdb_Track in which the transferred field is false)

itdb_playlists_number ()

guint32             itdb_playlists_number               (Itdb_iTunesDB *itdb);

Counts the number of playlists stored in itdb

itdb :

 an Itdb_iTunesDB

Returns :

 the number of playlists in itdb (including the master playlist)

ItdbUserDataDestroyFunc ()

void                (*ItdbUserDataDestroyFunc)          (gpointer userdata);

Function called to free userdata

userdata :

 A gpointer to user data

ItdbUserDataDuplicateFunc ()

gpointer            (*ItdbUserDataDuplicateFunc)        (gpointer userdata);

Function called to duplicate userdata

userdata :

 A gpointer to user data

Returns :

 A gpointer