gio.pollable_output_stream_mixin
Module for PollableOutputStream interface mixin
Templates 2
gio.pollable_output_stream.PollableOutputStream is implemented by gio.output_stream.OutputStreams that can be polled for readiness to write. This can be used when interfacing with a non-GIO API that expects UNIX-file-descriptor-style asynchronous I/O rather than GIO-style.
Some classes may implement gio.pollable_output_stream.PollableOutputStream but have only certain instances of that class be pollable. If gio.pollable_output_stream.PollableOutputStream.canPoll returns false, then the behavior of other gio.pollable_output_stream.PollableOutputStream methods is undefined.
Checks if stream is actually pollable. Some classes may implement #GPollableOutputStream but have only certain instances of that class be pollable. If this method returns false, then the behavior of other #GPollableOutputStream methods is undefined.
For any given stream, the value returned by this method is constant; a stream cannot switch from pollable to non-pollable or vice versa.
Returns
Creates a #GSource that triggers when stream can be written, or cancellable is triggered or an error occurs. The callback on the source is of the #GPollableSourceFunc type.
As with gio.pollable_output_stream.PollableOutputStream.isWritable, it is possible that the stream may not actually be writable even after the source triggers, so you should use gio.pollable_output_stream.PollableOutputStream.writeNonblocking rather than gio.output_stream.OutputStream.write from the callback.
The behaviour of this method is undefined if gio.pollable_output_stream.PollableOutputStream.canPoll returns false for stream.
Parameters
cancellable | a #GCancellable, or null |
Returns
Checks if stream can be written.
Note that some stream types may not be able to implement this 100% reliably, and it is possible that a call to gio.output_stream.OutputStream.write after this returns true would still block. To guarantee non-blocking behavior, you should always use gio.pollable_output_stream.PollableOutputStream.writeNonblocking, which will return a gio.types.IOErrorEnum.WouldBlock error rather than blocking.
The behaviour of this method is undefined if gio.pollable_output_stream.PollableOutputStream.canPoll returns false for stream.
Returns
has occurred on stream, this will result in gio.pollable_output_stream.PollableOutputStream.isWritable returning true, and the next attempt to write will return the error.
Attempts to write up to count bytes from buffer to stream, as with gio.output_stream.OutputStream.write. If stream is not currently writable, this will immediately return gio.types.IOErrorEnum.WouldBlock, and you can use gio.pollable_output_stream.PollableOutputStream.createSource to create a #GSource that will be triggered when stream is writable.
Note that since this method never blocks, you cannot actually use cancellable to cancel it. However, it will return an error if cancellable has already been cancelled when you call, which may happen if you call this method after a source triggers due to having been cancelled.
Also note that if gio.types.IOErrorEnum.WouldBlock is returned some underlying transports like D/TLS require that you re-send the same buffer and count in the next write call.
The behaviour of this method is undefined if gio.pollable_output_stream.PollableOutputStream.canPoll returns false for stream.
Parameters
buffer | a buffer to write data from |
cancellable | a #GCancellable, or null |
Returns
Throws
Attempts to write the bytes contained in the n_vectors vectors to stream, as with gio.output_stream.OutputStream.writev. If stream is not currently writable, this will immediately return %G_POLLABLE_RETURN_WOULD_BLOCK, and you can use gio.pollable_output_stream.PollableOutputStream.createSource to create a #GSource that will be triggered when stream is writable. error will not be set in that case.
Note that since this method never blocks, you cannot actually use cancellable to cancel it. However, it will return an error if cancellable has already been cancelled when you call, which may happen if you call this method after a source triggers due to having been cancelled.
Also note that if gio.types.PollableReturn.WouldBlock is returned some underlying transports like D/TLS require that you re-send the same vectors and n_vectors in the next write call.
The behaviour of this method is undefined if gio.pollable_output_stream.PollableOutputStream.canPoll returns false for stream.
Parameters
vectors | the buffer containing the #GOutputVectors to write. |
bytesWritten | location to store the number of bytes that were written to the stream |
cancellable | a #GCancellable, or null |
Returns
if the stream is not currently writable (and error is not set), or gio.types.PollableReturn.Failed if there was an error in which case error will be set.
Throws
Fluent builder implementation template for gio.pollable_output_stream.PollableOutputStream