[Tracker] Request for review, API allowing external software like MTP daemons to get metadata as correct sparql insert

[Philip Van Hoof <philip codeminded be>]

Hi guys,

I have finished my feature that allows MTP daemons to through an API get
a correct SPARQL INSERT query with extracted metadata for a file.

This is the branch: extract-sparql 
http://git.gnome.org/browse/tracker/log/?h=extract-sparql

This is the currently only commit:
http://git.gnome.org/browse/tracker/commit/?h=extract-sparql&id=e4af9b34e22b60d37251426a29dfcd9b566f6e0e


This is the newly added API:

    static void
    on_finished (GObject *none, GAsyncResult *result, gpointer user_data)
    {
        GMainLoop *loop = user_data;
        GError *error = NULL;
        gchar *sparql = tracker_extract_get_sparql_finish (result, &error);
    
        if (error == NULL) {
                g_print ("%s", sparql);
                g_free (sparql);
        } else {
                g_error("%s", error->message);
        }
    
        g_clear_error (&error);
    
        g_main_loop_quit (loop);
    }
    
    int main (int argc, char **argv)
    {
        const gchar *file = "/tmp/file.png";
        const gchar *dest = "file:///tmp/destination.png"
        GMainLoop *loop;
    
        g_type_init();
    
        loop = g_main_loop_new (NULL, FALSE);
        tracker_extract_get_sparql (file, dest, NULL, time(0),
                                    time(0), on_finished, loop);
    
        g_main_loop_run (loop);
    
        g_object_unref (loop);
    
        return 0;
  }

I have also added usage of the API to the tracker-sparql binary:

$ cp /home/pvanhoof/Documents/Photos/pasfoto-small.png /tmp/tempfile.png
$ /opt/tracker/bin/tracker-sparql --metadata-file-path=/tmp/tempfile.png \
        --metadata-graph-urn=urn:uuid:173b2520-4828-11e2-bcfd-0800200c9a66 \
        --metadata-dest-url=file:///home/pvanhoof/Documents/Photos/photo.png


INSERT SILENT {
GRAPH <urn:uuid:173b2520-4828-11e2-bcfd-0800200c9a66> {
_:file a nfo:FileDataObject , nie:InformationElement ;
         nfo:fileName "photo.png" ;
         nfo:fileSize 38155 ;
         nfo:fileLastModified "2012-12-17T09:20:18Z" ;
         nfo:fileLastAccessed "2012-12-17T09:20:18Z" ;
         nie:isStoredAs _:file ;
         nie:url "file:///home/pvanhoof/Documents/Photos/photo.png" ;
         nie:mimeType "image/png" ;
         a nfo:FileDataObject ;
         nie:dataSource <urn:nepomuk:datasource:9291a450-1d49-11de-8c30-0800200c9a66> ;
         tracker:available true .
_:file a nfo:Image , nmm:Photo ;
         nfo:width 150 ;
         nfo:height 192 ;
         nmm:dlnaProfile "PNG_LRG" ;
         nmm:dlnaMime "image/png" .

}
}

$ 


Please review.

Kind regards,

Philip

-- 


Philip Van Hoof
Software developer
Codeminded BVBA - http://codeminded.be