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TrackerDecoratorTrackerDecorator — A miner tasked with listening for DB resource changes and extracting metadata |
Functions
GQuark | tracker_decorator_error_quark () |
const gchar * | tracker_decorator_get_data_source () |
const gchar ** | tracker_decorator_get_class_names () |
guint | tracker_decorator_get_n_items () |
void | tracker_decorator_prepend_id () |
void | tracker_decorator_delete_id () |
void | tracker_decorator_next () |
TrackerDecoratorInfo * | tracker_decorator_next_finish () |
void | tracker_decorator_set_priority_rdf_types () |
TrackerDecoratorInfo * | tracker_decorator_info_ref () |
void | tracker_decorator_info_unref () |
const gchar * | tracker_decorator_info_get_urn () |
const gchar * | tracker_decorator_info_get_url () |
const gchar * | tracker_decorator_info_get_mimetype () |
GTask * | tracker_decorator_info_get_task () |
void | tracker_decorator_info_complete () |
void | tracker_decorator_info_complete_error () |
Properties
GStrv | class-names | Read / Write |
gint | commit-batch-size | Read / Write |
gchar * | data-source | Read / Write / Construct Only |
GStrv | priority-rdf-types | Write |
Description
TrackerDecorator watches for signal updates based on content changes in the database. When new files are added initially, only simple metadata exists, for example, name, size, mtime, etc. The TrackerDecorator queues files for extended metadata extraction (i.e. for tracker-extract to fetch metadata specific to the file type) for example 'nmm:whiteBalance' for a picture.
Functions
tracker_decorator_error_quark ()
GQuark
tracker_decorator_error_quark (void
);
Gives the caller the GQuark used to identify TrackerDecorator errors in GError structures. The GQuark is used as the domain for the error.
Since: 0.18.
tracker_decorator_get_data_source ()
const gchar *
tracker_decorator_get_data_source (TrackerDecorator *decorator
);
The unique string identifying this TrackerDecorator that has extracted the extended metadata. This is essentially an identifier so it's clear WHO has extracted this extended metadata.
Since: 0.18.
tracker_decorator_get_class_names ()
const gchar **
tracker_decorator_get_class_names (TrackerDecorator *decorator
);
This function returns a string list of class names which are being updated with extended metadata. An example would be 'nfo:Document'.
Since: 0.18.
tracker_decorator_get_n_items ()
guint
tracker_decorator_get_n_items (TrackerDecorator *decorator
);
Get the number of items left in the queue to be processed. This indicates content that may already exist in Tracker but is waiting to be further flurished with metadata with a 2nd pass extraction or index.
Since: 0.18.
tracker_decorator_prepend_id ()
void tracker_decorator_prepend_id (TrackerDecorator *decorator
,gint id
,gint class_name_id
);
Adds resource needing extended metadata extraction to the queue.
id
is the same IDs emitted by tracker-store when the database is updated for
consistency. For details, see the GraphUpdated signal.
Since: 0.18.
tracker_decorator_delete_id ()
void tracker_decorator_delete_id (TrackerDecorator *decorator
,gint id
);
Deletes resource needing extended metadata extraction from the
queue. id
is the same IDs emitted by tracker-store when the database is
updated for consistency. For details, see the GraphUpdated signal.
Since: 0.18.
tracker_decorator_next ()
void tracker_decorator_next (TrackerDecorator *decorator
,GCancellable *cancellable
,GAsyncReadyCallback callback
,gpointer user_data
);
Processes the next resource in the queue to have extended metadata extracted. If the item in the queue has been completed already, it signals it's completion instead.
This function will give a GError if the miner is paused at the time it is called.
Parameters
decorator |
||
cancellable |
a GCancellable. |
|
callback |
a GAsyncReadyCallback. |
|
user_data |
user_data for |
Since: 0.18.
tracker_decorator_next_finish ()
TrackerDecoratorInfo * tracker_decorator_next_finish (TrackerDecorator *decorator
,GAsyncResult *result
,GError **error
);
Should be called in the callback function provided to
tracker_decorator_next()
to return the result of the task be it an
error or not.
Returns
a TrackerDecoratorInfo on success or
NULL on error. Free with tracker_decorator_info_unref()
.
[transfer full]
Since: 0.18.
tracker_decorator_set_priority_rdf_types ()
void tracker_decorator_set_priority_rdf_types (TrackerDecorator *decorator
,const gchar * const *rdf_types
);
Re-evaluate the priority queues internally to ensure that
rdf_types
are handled before all other content. This is useful for
applications that need their content available sooner than the
standard time it would take to index content.
Since: 0.18.
tracker_decorator_info_ref ()
TrackerDecoratorInfo *
tracker_decorator_info_ref (TrackerDecoratorInfo *info
);
Increases the reference count of info
by 1.
Since: 0.18.
tracker_decorator_info_unref ()
void
tracker_decorator_info_unref (TrackerDecoratorInfo *info
);
Decreases the reference count of info
by 1 and frees it when the
reference count reaches 0.
Since: 0.18.
tracker_decorator_info_get_urn ()
const gchar *
tracker_decorator_info_get_urn (TrackerDecoratorInfo *info
);
A URN is a Uniform Resource Name and should be a unique identifier for a resource in the database.
Since: 0.18.
tracker_decorator_info_get_url ()
const gchar *
tracker_decorator_info_get_url (TrackerDecoratorInfo *info
);
A URL is a Uniform Resource Locator and should be a location associated with a resource in the database. For example, 'file:///tmp/foo.txt'.
Since: 0.18.
tracker_decorator_info_get_mimetype ()
const gchar *
tracker_decorator_info_get_mimetype (TrackerDecoratorInfo *info
);
A MIME¹ type is a way of describing the content type of a file or set of data. An example would be 'text/plain' for a clear text document or file.
¹: http://en.wikipedia.org/wiki/MIME
Since: 0.18.
tracker_decorator_info_get_task ()
GTask *
tracker_decorator_info_get_task (TrackerDecoratorInfo *info
);
Get the GTask associated with retrieving extended metadata and information for a URN in Tracker.
The task object's data (accessible with g_task_get_task_data()
) is the
TrackerSparqlBuilder that you must populate with the results of the
metadata extraction. This can also be accessed with
tracker_decorator_info_get_sparql()
.
Returns
the GTask for TrackerDecoratorInfo on success or NULL if there is no existing GTask.
[transfer none]
Since: 0.18.
tracker_decorator_info_complete ()
void tracker_decorator_info_complete (TrackerDecoratorInfo *info
,gchar *sparql
);
Completes the task associated to this TrackerDecoratorInfo.
Takes ownership of sparql
.
Since: 2.0
Types and Values
struct TrackerDecorator
struct TrackerDecorator;
Abstract miner object for passive extended metadata indexing, i.e. data past the basic information such as file name, size, etc.
struct TrackerDecoratorClass
struct TrackerDecoratorClass { TrackerMinerClass parent_class; void (* items_available) (TrackerDecorator *decorator); void (* finished) (TrackerDecorator *decorator); /* <Private> */ gpointer padding[10]; };
An implementation that takes care of extracting extra metadata specific to file types by talking to tracker-extract.
Based on TrackerMinerClass.
enum TrackerDecoratorError
Possible errors returned when calling tracker_decorator_next_finish()
.
Members
There is no item to be processed
next. It is entirely possible to have a ::items_available signal
emitted and then have this error when calling
|
||
No work was done or will be done because the miner is currently paused. |
Property Details
The “class-names”
property
“class-names” GStrv
rdfs:Class objects to listen to for changes.
Flags: Read / Write
The “commit-batch-size”
property
“commit-batch-size” gint
Number of items per update batch.
Flags: Read / Write
Allowed values: >= 0
Default value: 200
The “data-source”
property
“data-source” gchar *
nie:DataSource to use in this decorator.
Flags: Read / Write / Construct Only
Default value: NULL
Signal Details
The “finished”
signal
void user_function (TrackerDecorator *decorator, gpointer user_data)
The ::finished signal will be emitted whenever the TrackerDecorator has finished extracted extended metadata for resources in the database.
Parameters
decorator |
the TrackerDecorator |
|
user_data |
user data set when the signal handler was connected. |
Flags: Run Last
Since: 0.18.
The “items-available”
signal
void user_function (TrackerDecorator *decorator, gpointer user_data)
The ::items-available signal will be emitted whenever the TrackerDecorator sees resources that are available for extended metadata extraction.
Parameters
decorator |
the TrackerDecorator |
|
user_data |
user data set when the signal handler was connected. |
Flags: Run Last
Since: 0.18.