GI.Gio.Interfaces.PollableInputStream

PollableInputStream is implemented by GInputStreams 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.

Since: 2.28

Exported types

newtype PollableInputStream

Memory-managed wrapper type.

Constructors

PollableInputStream (ManagedPtr PollableInputStream)

Instances

Eq PollableInputStream

Defined in GI.Gio.Interfaces.PollableInputStream

Methods

(==) :: PollableInputStream -> PollableInputStream -> Bool

(/=) :: PollableInputStream -> PollableInputStream -> Bool

IsGValue PollableInputStream

Convert PollableInputStream to and from GValue with toGValue and fromGValue.

Defined in GI.Gio.Interfaces.PollableInputStream

Methods

toGValue :: PollableInputStream -> IO GValue

fromGValue :: GValue -> IO PollableInputStream

ManagedPtrNewtype PollableInputStream

Defined in GI.Gio.Interfaces.PollableInputStream

Methods

toManagedPtr :: PollableInputStream -> ManagedPtr PollableInputStream

TypedObject PollableInputStream

Defined in GI.Gio.Interfaces.PollableInputStream

Methods

glibType :: IO GType

GObject PollableInputStream

Defined in GI.Gio.Interfaces.PollableInputStream

HasParentTypes PollableInputStream

Defined in GI.Gio.Interfaces.PollableInputStream

type ParentTypes PollableInputStream

Defined in GI.Gio.Interfaces.PollableInputStream

type ParentTypes PollableInputStream = '[InputStream, Object]

class (GObject o, IsDescendantOf PollableInputStream o) => IsPollableInputStream o

Type class for types which can be safely cast to PollableInputStream, for instance with toPollableInputStream.

Instances

(GObject o, IsDescendantOf PollableInputStream o) => IsPollableInputStream o

Defined in GI.Gio.Interfaces.PollableInputStream

toPollableInputStream :: (MonadIO m, IsPollableInputStream o) => o -> m PollableInputStream

Cast to PollableInputStream, for types for which this is known to be safe. For general casts, use castTo.

Methods

Overloaded methods

canPoll

pollableInputStreamCanPoll

Arguments

:: (HasCallStack, MonadIO m, IsPollableInputStream a)

=> a

stream: a PollableInputStream.

-> m Bool

Returns: True if stream is pollable, False if not.

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

Since: 2.28

createSource

pollableInputStreamCreateSource

Arguments

:: (HasCallStack, MonadIO m, IsPollableInputStream a, IsCancellable b)

=> a

stream: a PollableInputStream.

-> Maybe b

cancellable: a Cancellable, or Nothing

-> m Source

Returns: a new Source

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

As with pollableInputStreamIsReadable, it is possible that the stream may not actually be readable even after the source triggers, so you should use pollableInputStreamReadNonblocking rather than inputStreamRead from the callback.

Since: 2.28

isReadable

pollableInputStreamIsReadable

Arguments

:: (HasCallStack, MonadIO m, IsPollableInputStream a)

=> a

stream: a PollableInputStream.

-> m Bool

Returns: True if stream is readable, False if not. If an error has occurred on stream, this will result in pollableInputStreamIsReadable returning True, and the next attempt to read will return the error.

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 inputStreamRead after this returns True would still block. To guarantee non-blocking behavior, you should always use pollableInputStreamReadNonblocking, which will return a IOErrorEnumWouldBlock error rather than blocking.

Since: 2.28

readNonblocking

pollableInputStreamReadNonblocking

Arguments

:: (HasCallStack, MonadIO m, IsPollableInputStream a, IsCancellable b)

=> a

stream: a PollableInputStream

-> Maybe ByteString

buffer: a buffer to read data into (which should be at least count bytes long).

-> Maybe b

cancellable: a Cancellable, or Nothing

-> m Int64

Returns: the number of bytes read, or -1 on error (including IOErrorEnumWouldBlock). (Can throw GError)

Attempts to read up to count bytes from stream into buffer, as with inputStreamRead. If stream is not currently readable, this will immediately return IOErrorEnumWouldBlock, and you can use pollableInputStreamCreateSource to create a Source 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.