libmediaart Library Reference Manual: Cache

Cache

Cache — Caching and lookup of stored media art.

Functions

gboolean	media_art_get_path ()
gboolean	media_art_get_file ()
gboolean	media_art_remove ()
void	media_art_remove_async ()
gboolean	media_art_remove_finish ()
gchar *	media_art_strip_invalid_entities ()

Includes

#include <libmediaart/mediaart.h>

Description

These functions give you access to the media art that has been extracted and saved. There are normally two places the media art will be located in. These locations store symlinks not real copies of the content:

The user's XDG_CACHE_HOME directory (usually ~/.cache/media-art/)
The local file system's top level .mediaartlocal directory (for example /media/martyn/pendrive/.mediaartlocal/)

To find the media art for a given media file, use the function media_art_get_file() (you can also use media_art_get_path(), which does the same thing but for path strings instead of GFile objects).

If media art for the file is not found in the cache, these functions will return NULL. You may find some embedded media art upon loading the file, and you can use media_art_process_buffer() to convert it to the correct format and save it in the cache for next time. The media_art_process_file() function also supports searching for external media art images using a basic heuristic.

Functions

media_art_get_path ()

gboolean
media_art_get_path (const gchar *artist,
                    const gchar *title,
                    const gchar *prefix,
                    gchar **cache_path);

This function calls media_art_get_file() by creating a GFile for uri and passing the same arguments to media_art_get_file(). For more details about what this function does, see media_art_get_file().

Get the path to media art for a given resource. Newly allocated data returned in cache_path must be freed with g_free().

Parameters

artist	the artist.	[allow-none]
title	the title.	[allow-none]
prefix	the prefix, for example "album".	[allow-none]
cache_path	a string representing the path to the cache for this media art path or `NULL`.	[out][transfer full][allow-none]

Returns

TRUE if cache_path was returned, otherwise FALSE.

Since 0.2.0

media_art_get_file ()

gboolean
media_art_get_file (const gchar *artist,
                    const gchar *title,
                    const gchar *prefix,
                    GFile **cache_file);

Gets the files pointing to cache files suitable for storing the media art provided by the artist , title and file arguments. cache_file will point to a location in the XDG user cache directory..

The cache_file relates to a symlink stored in XDG cache directories for the user. A cache_file would be expected to look like file:///home/martyn/.cache/media-art/.... This is normally the location that is most useful (assuming the cache has been extracted in the first place).

When done, both GFiles must be freed with g_object_unref() if non-NULL.

This operation should not use i/o, but it depends on the backend GFile implementation.

Parameters

artist	the artist.	[allow-none]
title	the title.	[allow-none]
prefix	the prefix for cache files, for example "album".	[allow-none]
cache_file	a pointer to a GFile which represents the cached file for media art, or `NULL` a GFile representing the user's cache path, or `NULL` GFile representing the location of the local media art.	[out][transfer full][allow-none]

Returns

TRUE if cache_file was returned, otherwise FALSE.

Since 0.2.0

media_art_remove ()

gboolean
media_art_remove (const gchar *artist,
                  const gchar *album,
                  GCancellable *cancellable,
                  GError **error);

Removes media art for given album/artist provided.

If artist and album are NULL, ALL media art cache is removed.

Parameters

artist	artist the media art belongs to
album	album the media art belongs or `NULL`.	[allow-none]
cancellable	optional GCancellable object, `NULL` to ignore.	[allow-none]
error	location to store the error occurring, or `NULL` to ignore

Returns

TRUE on success, otherwise FALSE where error will be set.

Since 0.2.0

media_art_remove_async ()

void
media_art_remove_async (const gchar *artist,
                        const gchar *album,
                        gint io_priority,
                        GObject *source_object,
                        GCancellable *cancellable,
                        GAsyncReadyCallback callback,
                        gpointer user_data);

Removes media art for given album/artist provided. Precisely the same operation as media_art_remove() is performing, but asynchronously.

When all i/o for the operation is finished the callback will be called.

In case of a partial error the callback will be called with any succeeding items and no error, and on the next request the error will be reported. If a request is cancelled the callback will be called with G_IO_ERROR_CANCELLED.

During an async request no other sync and async calls are allowed, and will result in G_IO_ERROR_PENDING errors.

Any outstanding i/o request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is G_PRIORITY_DEFAULT.

Parameters

artist	artist the media art belongs to
album	album the media art belongs or `NULL`.	[allow-none]
io_priority	the I/O priority of the request
source_object	the GObject this task belongs to, can be `NULL`.	[allow-none]
cancellable	optional GCancellable object, `NULL` to ignore.	[allow-none]
callback	a GAsyncReadyCallback to call when the request is satisfied.	[scope async]
user_data	the data to pass to callback function.	[closure]

Since 0.7.0

media_art_remove_finish ()

gboolean
media_art_remove_finish (GObject *source_object,
                         GAsyncResult *result,
                         GError **error);

Finishes the asynchronous operation started with media_art_remove_async().

Parameters

source_object	the GObject this task belongs to, can be `NULL`.	[allow-none]
result	a GAsyncResult.
error	a GError location to store the error occurring, or `NULL` to ignore.

Returns

TRUE on success, otherwise FALSE when error will be set.

Since 0.7.0

media_art_strip_invalid_entities ()

gchar *
media_art_strip_invalid_entities (const gchar *original);

Strip a albumname or artistname string to prepare it for calculating the media art path with it. Certain characters and charactersets will be stripped and a newly allocated string returned which you must free with g_free().

This functions is used internally by media_art_get_file() and media_art_get_path(). You will not normally need to call it yourself.

This function provides the following features:

Invalid characters include: ()[]<>{}_!@#$^&*+=|\/"'?~;
Text inside brackets of(), {}, [] and <> pairs are removed.
Multiples of space characters are removed.

Parameters

original

original string

Returns

original stripped of invalid characters which must be freed. On error or if original is empty, NULL is returned.

Since 0.2.0

Cache

Functions

Includes

Description

Functions

media_art_get_path ()

Parameters

Returns

media_art_get_file ()

Parameters

Returns

media_art_remove ()

Parameters

Returns

media_art_remove_async ()

Parameters

media_art_remove_finish ()

Parameters

Returns

media_art_strip_invalid_entities ()

Parameters

Returns

Types and Values