* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General
- * Public License along with this library; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
- * Boston, MA 02111-1307, USA.
+ * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
*
* Author: Alexander Larsson <alexl@redhat.com>
*/
-#include <config.h>
+#include "config.h"
#include "gseekable.h"
#include "glibintl.h"
-static void g_seekable_base_init (gpointer g_class);
+/**
+ * SECTION:gseekable
+ * @short_description: Stream seeking interface
+ * @include: gio/gio.h
+ * @see_also: #GInputStream, #GOutputStream
+ *
+ * #GSeekable is implemented by streams (implementations of
+ * #GInputStream or #GOutputStream) that support seeking.
+ *
+ * Seekable streams largely fall into two categories: resizable and
+ * fixed-size.
+ *
+ * #GSeekable on fixed-sized streams is approximately the same as POSIX
+ * lseek() on a block device (for example: attmepting to seek past the
+ * end of the device is an error). Fixed streams typically cannot be
+ * truncated.
+ *
+ * #GSeekable on resizable streams is approximately the same as POSIX
+ * lseek() on a normal file. Seeking past the end and writing data will
+ * usually cause the stream to resize by introducing zero bytes.
+ **/
-GType
-g_seekable_get_type (void)
-{
- static GType seekable_type = 0;
-
- if (! seekable_type)
- {
- static const GTypeInfo seekable_info =
- {
- sizeof (GSeekableIface), /* class_size */
- g_seekable_base_init, /* base_init */
- NULL, /* base_finalize */
- NULL,
- NULL, /* class_finalize */
- NULL, /* class_data */
- 0,
- 0, /* n_preallocs */
- NULL
- };
-
- seekable_type =
- g_type_register_static (G_TYPE_INTERFACE, I_("GSeekable"),
- &seekable_info, 0);
-
- g_type_interface_add_prerequisite (seekable_type, G_TYPE_OBJECT);
- }
-
- return seekable_type;
-}
+typedef GSeekableIface GSeekableInterface;
+G_DEFINE_INTERFACE (GSeekable, g_seekable, G_TYPE_OBJECT)
static void
-g_seekable_base_init (gpointer g_class)
+g_seekable_default_init (GSeekableInterface *iface)
{
}
/**
* g_seekable_tell:
- * @seekable:
+ * @seekable: a #GSeekable.
*
- * Returns: a goffset.
+ * Tells the current position within the stream.
+ *
+ * Returns: the offset from the beginning of the buffer.
**/
goffset
g_seekable_tell (GSeekable *seekable)
/**
* g_seekable_can_seek:
- * @seekable:
+ * @seekable: a #GSeekable.
+ *
+ * Tests if the stream supports the #GSeekableIface.
*
* Returns: %TRUE if @seekable can be seeked. %FALSE otherwise.
**/
/**
* g_seekable_seek:
- * @seekable:
- * @offset:
- * @type:
- * @cancellable: optional #GCancellable object, %NULL to ignore.
- * @error: a #GError location to store the error occuring, or %NULL to
+ * @seekable: a #GSeekable.
+ * @offset: a #goffset.
+ * @type: a #GSeekType.
+ * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
+ * @error: a #GError location to store the error occurring, or %NULL to
* ignore.
- * Returns: %TRUE, %FALSE otherwise.
+ *
+ * Seeks in the stream by the given @offset, modified by @type.
+ *
+ * Attempting to seek past the end of the stream will have different
+ * results depending on if the stream is fixed-sized or resizable. If
+ * the stream is resizable then seeking past the end and then writing
+ * will result in zeros filling the empty space. Seeking past the end
+ * of a resizable stream and reading will result in EOF. Seeking past
+ * the end of a fixed-sized stream will fail.
+ *
+ * Any operation that would result in a negative offset will fail.
+ *
+ * If @cancellable is not %NULL, then the operation can be cancelled by
+ * triggering the cancellable object from another thread. If the operation
+ * was cancelled, the error %G_IO_ERROR_CANCELLED will be returned.
+ *
+ * Returns: %TRUE if successful. If an error
+ * has occurred, this function will return %FALSE and set @error
+ * appropriately if present.
**/
gboolean
g_seekable_seek (GSeekable *seekable,
/**
* g_seekable_can_truncate:
- * @seekable:
+ * @seekable: a #GSeekable.
*
- * Returns:
+ * Tests if the stream can be truncated.
+ *
+ * Returns: %TRUE if the stream can be truncated, %FALSE otherwise.
**/
gboolean
g_seekable_can_truncate (GSeekable *seekable)
/**
* g_seekable_truncate:
- * @seekable:
- * @offset:
- * @cancellable: optional #GCancellable object, %NULL to ignore.
- * @error: a #GError location to store the error occuring, or %NULL to
+ * @seekable: a #GSeekable.
+ * @offset: a #goffset.
+ * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
+ * @error: a #GError location to store the error occurring, or %NULL to
* ignore.
- * Returns:
+ *
+ * Truncates a stream with a given #offset.
+ *
+ * If @cancellable is not %NULL, then the operation can be cancelled by
+ * triggering the cancellable object from another thread. If the operation
+ * was cancelled, the error %G_IO_ERROR_CANCELLED will be returned. If an
+ * operation was partially finished when the operation was cancelled the
+ * partial result will be returned, without an error.
+ *
+ * Virtual: truncate_fn
+ * Returns: %TRUE if successful. If an error
+ * has occurred, this function will return %FALSE and set @error
+ * appropriately if present.
**/
gboolean
g_seekable_truncate (GSeekable *seekable,
iface = G_SEEKABLE_GET_IFACE (seekable);
- return (* iface->truncate) (seekable, offset, cancellable, error);
+ return (* iface->truncate_fn) (seekable, offset, cancellable, error);
}
-
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