gio.pollable_input_stream_mixin

Module for [PollableInputStream] interface mixin

tmpl PollableInputStreamGidBuilderT PollableInputStreamT

Templates 2

tmplPollableInputStreamT()

[gio.pollable_input_stream.PollableInputStream] is implemented by [gio.input_stream.InputStream]s that can be polled for readiness to read. 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_input_stream.PollableInputStream] but have only certain instances of that class be pollable. If [gio.pollable_input_stream.PollableInputStream.canPoll] returns false, then the behavior of other [gio.pollable_input_stream.PollableInputStream] methods is undefined.

Functions

bool canPoll()

Checks if stream is actually pollable. Some classes may implement #GPollableInputStream but have only certain instances of that class be pollable. If this method returns false, then the behavior of other #GPollableInputStream 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

true if stream is pollable, false if not.

glib.source.Source createSource(gio.cancellable.Cancellable cancellable = null)

Creates a #GSource that triggers when stream can be read, or cancellable is triggered or an error occurs. The callback on the source is of the #GPollableSourceFunc type.

As with [gio.pollable_input_stream.PollableInputStream.isReadable], it is possible that the stream may not actually be readable even after the source triggers, so you should use [gio.pollable_input_stream.PollableInputStream.readNonblocking] rather than [gio.input_stream.InputStream.read] from the callback.

The behaviour of this method is undefined if [gio.pollable_input_stream.PollableInputStream.canPoll] returns false for stream.

Parameters

cancellable a #GCancellable, or null

Returns

a new #GSource

bool isReadable()

Checks if stream can be read.

Note that some stream types may not be able to implement this 100% reliably, and it is possible that a call to [gio.input_stream.InputStream.read] after this returns true would still block. To guarantee non-blocking behavior, you should always use [gio.pollable_input_stream.PollableInputStream.readNonblocking], which will return a [gio.types.IOErrorEnum.WouldBlock] error rather than blocking.

The behaviour of this method is undefined if [gio.pollable_input_stream.PollableInputStream.canPoll] returns false for stream.

Returns

true if stream is readable, false if not. If an error

has occurred on stream, this will result in [gio.pollable_input_stream.PollableInputStream.isReadable] returning true, and the next attempt to read will return the error.

ptrdiff_t readNonblocking(ref ubyte[] buffer, gio.cancellable.Cancellable cancellable = null)

Attempts to read up to count bytes from stream into buffer, as with [gio.input_stream.InputStream.read]. If stream is not currently readable, this will immediately return [gio.types.IOErrorEnum.WouldBlock], and you can use [gio.pollable_input_stream.PollableInputStream.createSource] to create a #GSource that will be triggered when stream is readable.

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.

The behaviour of this method is undefined if [gio.pollable_input_stream.PollableInputStream.canPoll] returns false for stream.

Parameters

`buffer`	a buffer to read data into (which should be at least count bytes long).
`cancellable`	a #GCancellable, or null

Returns

the number of bytes read, or -1 on error (including

[gio.types.IOErrorEnum.WouldBlock]).

Throws

[ErrorWrap]

tmplPollableInputStreamGidBuilderT()