GI.Gio.Interfaces.Seekable

Seekable is implemented by streams (implementations of InputStream or OutputStream) that support seeking.

Seekable streams largely fall into two categories: resizable and fixed-size.

Seekable on fixed-sized streams is approximately the same as POSIX lseek() on a block device (for example: attmepting to seek past the end of the device is an error). Fixed streams typically cannot be truncated.

Seekable 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.

Exported types

newtype Seekable

Constructors

Seekable (ManagedPtr Seekable)

Instances

GObject Seekable

Methods

gobjectType :: Seekable -> IO GType

IsObject Seekable

IsSeekable Seekable

((~) * info (ResolveSeekableMethod t Seekable), MethodInfo * info Seekable p) => IsLabel t (Seekable -> p)

Methods

fromLabel :: Proxy# Symbol t -> Seekable -> p

((~) * info (ResolveSeekableMethod t Seekable), MethodInfo * info Seekable p) => IsLabelProxy t (Seekable -> p)

Methods

fromLabelProxy :: Proxy Symbol t -> Seekable -> p

HasAttributeList * Seekable

type AttributeList Seekable

type AttributeList Seekable

type SignalList Seekable

type SignalList Seekable

noSeekable :: Maybe Seekable

class GObject o => IsSeekable o

Instances

(GObject a, UnknownAncestorError Constraint Seekable a) => IsSeekable a

IsSeekable FileOutputStream

IsSeekable FileInputStream

IsSeekable FileIOStream

IsSeekable BufferedInputStream

IsSeekable Seekable

IsSeekable BufferedOutputStream

IsSeekable MemoryOutputStream

IsSeekable MemoryInputStream

IsSeekable DataOutputStream

IsSeekable DataInputStream

toSeekable :: IsSeekable o => o -> IO Seekable

Methods

canSeek

data SeekableCanSeekMethodInfo

Instances

((~) * signature (m Bool), MonadIO m, IsSeekable a) => MethodInfo * SeekableCanSeekMethodInfo a signature

Methods

overloadedMethod :: MethodProxy SeekableCanSeekMethodInfo a -> signature -> s

seekableCanSeek

Arguments

:: (HasCallStack, MonadIO m, IsSeekable a)

=> a

seekable: a Seekable.

-> m Bool

Returns: True if seekable can be seeked. False otherwise.

Tests if the stream supports the SeekableIface.

canTruncate

data SeekableCanTruncateMethodInfo

Instances

((~) * signature (m Bool), MonadIO m, IsSeekable a) => MethodInfo * SeekableCanTruncateMethodInfo a signature

Methods

overloadedMethod :: MethodProxy SeekableCanTruncateMethodInfo a -> signature -> s

seekableCanTruncate

Arguments

:: (HasCallStack, MonadIO m, IsSeekable a)

=> a

seekable: a Seekable.

-> m Bool

Returns: True if the stream can be truncated, False otherwise.

Tests if the stream can be truncated.

seek

data SeekableSeekMethodInfo

Instances

((~) * signature (Int64 -> SeekType -> Maybe b -> m ()), MonadIO m, IsSeekable a, IsCancellable b) => MethodInfo * SeekableSeekMethodInfo a signature

Methods

overloadedMethod :: MethodProxy SeekableSeekMethodInfo a -> signature -> s

seekableSeek

Arguments

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

=> a

seekable: a Seekable.

-> Int64

offset: a goffset.

-> SeekType

type: a SeekType.

-> Maybe b

cancellable: optional Cancellable object, Nothing to ignore.

-> m ()

(Can throw GError)

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 Nothing, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error IOErrorEnumCancelled will be returned.

tell

data SeekableTellMethodInfo

Instances

((~) * signature (m Int64), MonadIO m, IsSeekable a) => MethodInfo * SeekableTellMethodInfo a signature

Methods

overloadedMethod :: MethodProxy SeekableTellMethodInfo a -> signature -> s

seekableTell

Arguments

:: (HasCallStack, MonadIO m, IsSeekable a)

=> a

seekable: a Seekable.

-> m Int64

Returns: the offset from the beginning of the buffer.

Tells the current position within the stream.

truncate

data SeekableTruncateMethodInfo

Instances

((~) * signature (Int64 -> Maybe b -> m ()), MonadIO m, IsSeekable a, IsCancellable b) => MethodInfo * SeekableTruncateMethodInfo a signature

Methods

overloadedMethod :: MethodProxy SeekableTruncateMethodInfo a -> signature -> s

seekableTruncate

Arguments

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

=> a

seekable: a Seekable.

-> Int64

offset: a goffset.

-> Maybe b

cancellable: optional Cancellable object, Nothing to ignore.

-> m ()

(Can throw GError)

Truncates a stream with a given offset.

If cancellable is not Nothing, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error IOErrorEnumCancelled will be returned. If an operation was partially finished when the operation was cancelled the partial result will be returned, without an error.