Gio.IOStream

g GObject.Object GObject.Object Gio.IOStream Gio.IOStream GObject.Object->Gio.IOStream

Subclasses:Gio.FileIOStream, Gio.SimpleIOStream, Gio.SocketConnection, Gio.TlsConnection

Methods

Inherited:GObject.Object (37)
Structs:GObject.ObjectClass (5)
class splice_finish (result)
  clear_pending ()
  close (cancellable)
  close_async (io_priority, cancellable, callback, *user_data)
  close_finish (result)
  get_input_stream ()
  get_output_stream ()
  has_pending ()
  is_closed ()
  set_pending ()
  splice_async (stream2, flags, io_priority, cancellable, callback, *user_data)

Virtual Methods

Inherited:GObject.Object (7)
  do_close_async (io_priority, cancellable, callback, *user_data)
  do_close_finish (result)
  do_close_fn (cancellable)
  do_get_input_stream ()
  do_get_output_stream ()

Properties

Name Type Flags Short Description
closed bool r Is the stream closed
input-stream Gio.InputStream r The Gio.InputStream to read from
output-stream Gio.OutputStream r The Gio.OutputStream to write to

Signals

Inherited:GObject.Object (1)

Fields

Inherited:GObject.Object (1)
Name Type Access Description
parent_instance GObject.Object r  

Class Details

class Gio.IOStream(**kwargs)
Bases:GObject.Object
Abstract:Yes
Structure:Gio.IOStreamClass

Gio.IOStream represents an object that has both read and write streams. Generally the two streams act as separate input and output streams, but they share some common resources and state. For instance, for seekable streams, both streams may use the same position.

Examples of Gio.IOStream objects are Gio.SocketConnection, which represents a two-way network connection; and Gio.FileIOStream, which represents a file handle opened in read-write mode.

To do the actual reading and writing you need to get the substreams with Gio.IOStream.get_input_stream() and Gio.IOStream.get_output_stream().

The Gio.IOStream object owns the input and the output streams, not the other way around, so keeping the substreams alive will not keep the Gio.IOStream object alive. If the Gio.IOStream object is freed it will be closed, thus closing the substreams, so even if the substreams stay alive they will always return Gio.IOErrorEnum.CLOSED for all operations.

To close a stream use Gio.IOStream.close() which will close the common stream object and also the individual substreams. You can also close the substreams themselves. In most cases this only marks the substream as closed, so further I/O on it fails but common state in the Gio.IOStream may still be open. However, some streams may support “half-closed” states where one direction of the stream is actually shut down.

Operations on Gio.IOStreams cannot be started while another operation on the Gio.IOStream or its substreams is in progress. Specifically, an application can read from the Gio.InputStream and write to the Gio.OutputStream simultaneously (either in separate threads, or as asynchronous operations in the same thread), but an application cannot start any Gio.IOStream operation while there is a Gio.IOStream, Gio.InputStream or Gio.OutputStream operation in progress, and an application can’t start any Gio.InputStream or Gio.OutputStream operation while there is a Gio.IOStream operation in progress.

This is a product of individual stream operations being associated with a given GLib.MainContext (the thread-default context at the time the operation was started), rather than entire streams being associated with a single GLib.MainContext.

GIO may run operations on Gio.IOStreams from other (worker) threads, and this may be exposed to application code in the behaviour of wrapper streams, such as Gio.BufferedInputStream or Gio.TlsConnection. With such wrapper APIs, application code may only run operations on the base (wrapped) stream when the wrapper stream is idle. Note that the semantics of such operations may not be well-defined due to the state the wrapper stream leaves the base stream in (though they are guaranteed not to crash).

New in version 2.22.

classmethod splice_finish(result)[source]
Parameters:result (Gio.AsyncResult) – a Gio.AsyncResult.
Raises:GLib.Error
Returns:True on success, False otherwise.
Return type:bool

Finishes an asynchronous io stream splice operation.

New in version 2.28.

clear_pending()[source]

Clears the pending flag on self.

New in version 2.22.

close(cancellable)[source]
Parameters:cancellable (Gio.Cancellable or None) – optional Gio.Cancellable object, None to ignore
Raises:GLib.Error
Returns:True on success, False on failure
Return type:bool

Closes the stream, releasing resources related to it. This will also close the individual input and output streams, if they are not already closed.

Once the stream is closed, all other operations will return Gio.IOErrorEnum.CLOSED. Closing a stream multiple times will not return an error.

Closing a stream will automatically flush any outstanding buffers in the stream.

Streams will be automatically closed when the last reference is dropped, but you might want to call this function to make sure resources are released as early as possible.

Some streams might keep the backing store of the stream (e.g. a file descriptor) open after the stream is closed. See the documentation for the individual stream for details.

On failure the first error that happened will be reported, but the close operation will finish as much as possible. A stream that failed to close will still return Gio.IOErrorEnum.CLOSED for all operations. Still, it is important to check and report the error to the user, otherwise there might be a loss of data as all data might not be written.

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 Gio.IOErrorEnum.CANCELLED will be returned. Cancelling a close will still leave the stream closed, but some streams can use a faster close that doesn’t block to e.g. check errors.

The default implementation of this method just calls close on the individual input/output streams.

New in version 2.22.

close_async(io_priority, cancellable, callback, *user_data)[source]
Parameters:

Requests an asynchronous close of the stream, releasing resources related to it. When the operation is finished callback will be called. You can then call Gio.IOStream.close_finish() to get the result of the operation.

For behaviour details see Gio.IOStream.close().

The asynchronous methods have a default fallback that uses threads to implement asynchronicity, so they are optional for inheriting classes. However, if you override one you must override all.

New in version 2.22.

close_finish(result)[source]
Parameters:result (Gio.AsyncResult) – a Gio.AsyncResult
Raises:GLib.Error
Returns:True if stream was successfully closed, False otherwise.
Return type:bool

Closes a stream.

New in version 2.22.

get_input_stream()[source]
Returns:a Gio.InputStream, owned by the Gio.IOStream. Do not free.
Return type:Gio.InputStream

Gets the input stream for this object. This is used for reading.

New in version 2.22.

get_output_stream()[source]
Returns:a Gio.OutputStream, owned by the Gio.IOStream. Do not free.
Return type:Gio.OutputStream

Gets the output stream for this object. This is used for writing.

New in version 2.22.

has_pending()[source]
Returns:True if self has pending actions.
Return type:bool

Checks if a stream has pending actions.

New in version 2.22.

is_closed()[source]
Returns:True if the stream is closed.
Return type:bool

Checks if a stream is closed.

New in version 2.22.

set_pending()[source]
Raises:GLib.Error
Returns:True if pending was previously unset and is now set.
Return type:bool

Sets self to have actions pending. If the pending flag is already set or self is closed, it will return False and set error.

New in version 2.22.

splice_async(stream2, flags, io_priority, cancellable, callback, *user_data)[source]
Parameters:

Asynchronously splice the output stream of self to the input stream of stream2, and splice the output stream of stream2 to the input stream of self.

When the operation is finished callback will be called. You can then call Gio.IOStream.splice_finish() to get the result of the operation.

New in version 2.28.

do_close_async(io_priority, cancellable, callback, *user_data) virtual
Parameters:

Requests an asynchronous close of the stream, releasing resources related to it. When the operation is finished callback will be called. You can then call Gio.IOStream.close_finish() to get the result of the operation.

For behaviour details see Gio.IOStream.close().

The asynchronous methods have a default fallback that uses threads to implement asynchronicity, so they are optional for inheriting classes. However, if you override one you must override all.

New in version 2.22.

do_close_finish(result) virtual
Parameters:result (Gio.AsyncResult) – a Gio.AsyncResult
Returns:True if stream was successfully closed, False otherwise.
Return type:bool

Closes a stream.

New in version 2.22.

do_close_fn(cancellable) virtual
Parameters:cancellable (Gio.Cancellable or None) –
Return type:bool
do_get_input_stream() virtual
Returns:a Gio.InputStream, owned by the Gio.IOStream. Do not free.
Return type:Gio.InputStream

Gets the input stream for this object. This is used for reading.

New in version 2.22.

do_get_output_stream() virtual
Returns:a Gio.OutputStream, owned by the Gio.IOStream. Do not free.
Return type:Gio.OutputStream

Gets the output stream for this object. This is used for writing.

New in version 2.22.

Property Details

Gio.IOStream.props.closed
Name:closed
Type:bool
Default Value:False
Flags:READABLE

Is the stream closed

Gio.IOStream.props.input_stream
Name:input-stream
Type:Gio.InputStream
Default Value:None
Flags:READABLE

The Gio.InputStream to read from

Gio.IOStream.props.output_stream
Name:output-stream
Type:Gio.OutputStream
Default Value:None
Flags:READABLE

The Gio.OutputStream to write to