Gio.Seekable¶

interface

GSeekable is implemented by streams (implementations of InputStream or OutputStream) 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: attempting 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.

Methods¶

can_seek¶

def can_seek(self) -> bool

Tests if the stream supports the SeekableIface.

can_truncate¶

def can_truncate(self) -> bool

Tests if the length of the stream can be adjusted with Seekable.truncate.

seek¶

def seek(self, offset: int, type: GLib.SeekType | int, cancellable: Cancellable | None = ...) -> bool

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 None, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error IOErrorEnum.CANCELLED will be returned.

Parameters:

offset — a #goffset.
type — a GLib.SeekType.
cancellable — optional Cancellable object, None to ignore.

tell¶

def tell(self) -> int

Tells the current position within the stream.

truncate¶

def truncate(self, offset: int, cancellable: Cancellable | None = ...) -> bool

Sets the length of the stream to offset. If the stream was previously larger than offset, the extra data is discarded. If the stream was previously shorter than offset, it is extended with NUL ('\0') bytes.

If cancellable is not None, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error IOErrorEnum.CANCELLED will be returned. If an operation was partially finished when the operation was cancelled the partial result will be returned, without an error.

Parameters:

offset — new length for seekable, in bytes.
cancellable — optional Cancellable object, None to ignore.

Virtual methods¶

do_can_seek¶

def do_can_seek(self) -> bool

Tests if the stream supports the SeekableIface.

do_can_truncate¶

def do_can_truncate(self) -> bool

Tests if the length of the stream can be adjusted with Seekable.truncate.

do_seek¶

def do_seek(self, offset: int, type: GLib.SeekType | int, cancellable: Cancellable | None = ...) -> bool

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 None, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error IOErrorEnum.CANCELLED will be returned.

Parameters:

offset — a #goffset.
type — a GLib.SeekType.
cancellable — optional Cancellable object, None to ignore.

do_tell¶

def do_tell(self) -> int

Tells the current position within the stream.

do_truncate_fn¶

def do_truncate_fn(self, offset: int, cancellable: Cancellable | None = ...) -> bool

Sets the length of the stream to offset. If the stream was previously larger than offset, the extra data is discarded. If the stream was previously shorter than offset, it is extended with NUL ('\0') bytes.

If cancellable is not None, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error IOErrorEnum.CANCELLED will be returned. If an operation was partially finished when the operation was cancelled the partial result will be returned, without an error.

Parameters:

offset — new length for seekable, in bytes.
cancellable — optional Cancellable object, None to ignore.