GI.Gio.Objects.InputStream

InputStream has functions to read from a stream (inputStreamRead), to close a stream (inputStreamClose) and to skip some content (inputStreamSkip).

To copy the content of an input stream to an output stream without manually handling the reads and writes, use outputStreamSplice.

See the documentation for IOStream for details of thread safety of streaming APIs.

All of these functions have async variants too.

Exported types

newtype InputStream

Memory-managed wrapper type.

Constructors

InputStream (ManagedPtr InputStream)

Instances

GObject InputStream

Defined in GI.Gio.Objects.InputStream

Methods

gobjectType :: IO GType

HasParentTypes InputStream

Defined in GI.Gio.Objects.InputStream

type ParentTypes InputStream

Defined in GI.Gio.Objects.InputStream

type ParentTypes InputStream = Object ': ([] :: [Type])

class (GObject o, IsDescendantOf InputStream o) => IsInputStream o

Type class for types which can be safely cast to InputStream, for instance with toInputStream.

Instances

(GObject o, IsDescendantOf InputStream o) => IsInputStream o

Defined in GI.Gio.Objects.InputStream

toInputStream :: (MonadIO m, IsInputStream o) => o -> m InputStream

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

noInputStream :: Maybe InputStream

A convenience alias for Nothing :: Maybe InputStream.

Methods

clearPending

inputStreamClearPending

Arguments

:: (HasCallStack, MonadIO m, IsInputStream a)

=> a

stream: input stream

-> m ()

Clears the pending flag on stream.

close

inputStreamClose

Arguments

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

=> a

stream: A InputStream.

-> Maybe b

cancellable: optional Cancellable object, Nothing to ignore.

-> m ()

(Can throw GError)

Closes the stream, releasing resources related to it.

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

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 IOErrorEnumClosed for all operations. Still, it is important to check and report the error to the user.

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. 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.

closeAsync

inputStreamCloseAsync

Arguments

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

=> a

stream: A InputStream.

-> Int32

ioPriority: the [I/O priority][io-priority] of the request

-> Maybe b

cancellable: optional cancellable object

-> Maybe AsyncReadyCallback

callback: callback to call when the request is satisfied

-> m ()

Requests an asynchronous closes of the stream, releasing resources related to it. When the operation is finished callback will be called. You can then call inputStreamCloseFinish to get the result of the operation.

For behaviour details see inputStreamClose.

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.

closeFinish

inputStreamCloseFinish

Arguments

:: (HasCallStack, MonadIO m, IsInputStream a, IsAsyncResult b)

=> a

stream: a InputStream.

-> b

result: a AsyncResult.

-> m ()

(Can throw GError)

Finishes closing a stream asynchronously, started from inputStreamCloseAsync.

hasPending

inputStreamHasPending

Arguments

:: (HasCallStack, MonadIO m, IsInputStream a)

=> a

stream: input stream.

-> m Bool

Returns: True if stream has pending actions.

Checks if an input stream has pending actions.

isClosed

inputStreamIsClosed

Arguments

:: (HasCallStack, MonadIO m, IsInputStream a)

=> a

stream: input stream.

-> m Bool

Returns: True if the stream is closed.

Checks if an input stream is closed.

read

inputStreamRead

Arguments

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

=> a

stream: a InputStream.

-> ByteString

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

-> Maybe b

cancellable: optional Cancellable object, Nothing to ignore.

-> m Int64

Returns: Number of bytes read, or -1 on error, or 0 on end of file. (Can throw GError)

Tries to read count bytes from the stream into the buffer starting at buffer. Will block during this read.

If count is zero returns zero and does nothing. A value of count larger than G_MAXSSIZE will cause a IOErrorEnumInvalidArgument error.

On success, the number of bytes read into the buffer is returned. It is not an error if this is not the same as the requested size, as it can happen e.g. near the end of a file. Zero is returned on end of file (or if count is zero), but never otherwise.

The returned buffer is not a nul-terminated string, it can contain nul bytes at any position, and this function doesn't nul-terminate the buffer.

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.

On error -1 is returned and error is set accordingly.

readAll

inputStreamReadAll

Arguments

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

=> a

stream: a InputStream.

-> ByteString

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

-> Maybe b

cancellable: optional Cancellable object, Nothing to ignore.

-> m Word64

(Can throw GError)

Tries to read count bytes from the stream into the buffer starting at buffer. Will block during this read.

This function is similar to inputStreamRead, except it tries to read as many bytes as requested, only stopping on an error or end of stream.

On a successful read of count bytes, or if we reached the end of the stream, True is returned, and bytesRead is set to the number of bytes read into buffer.

If there is an error during the operation False is returned and error is set to indicate the error status.

As a special exception to the normal conventions for functions that use GError, if this function returns False (and sets error) then bytesRead will be set to the number of bytes that were successfully read before the error was encountered. This functionality is only available from C. If you need it from another language then you must write your own loop around inputStreamRead.

readAllAsync

inputStreamReadAllAsync

Arguments

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

=> a

stream: A InputStream

-> ByteString

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

-> Int32

ioPriority: the [I/O priority][io-priority] of the request

-> Maybe b

cancellable: optional Cancellable object, Nothing to ignore

-> Maybe AsyncReadyCallback

callback: callback to call when the request is satisfied

-> m ()

Request an asynchronous read of count bytes from the stream into the buffer starting at buffer.

This is the asynchronous equivalent of inputStreamReadAll.

Call inputStreamReadAllFinish to collect the result.

Any outstanding I/O request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is PRIORITY_DEFAULT.

Since: 2.44

readAllFinish

inputStreamReadAllFinish

Arguments

:: (HasCallStack, MonadIO m, IsInputStream a, IsAsyncResult b)

=> a

stream: a InputStream

-> b

result: a AsyncResult

-> m Word64

(Can throw GError)

Finishes an asynchronous stream read operation started with inputStreamReadAllAsync.

As a special exception to the normal conventions for functions that use GError, if this function returns False (and sets error) then bytesRead will be set to the number of bytes that were successfully read before the error was encountered. This functionality is only available from C. If you need it from another language then you must write your own loop around inputStreamReadAsync.

Since: 2.44

readAsync

inputStreamReadAsync

Arguments

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

=> a

stream: A InputStream.

-> Maybe ByteString

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

-> Int32

ioPriority: the [I/O priority][io-priority] of the request.

-> Maybe b

cancellable: optional Cancellable object, Nothing to ignore.

-> Maybe AsyncReadyCallback

callback: callback to call when the request is satisfied

-> m ()

Request an asynchronous read of count bytes from the stream into the buffer starting at buffer. When the operation is finished callback will be called. You can then call inputStreamReadFinish to get the result of the operation.

During an async request no other sync and async calls are allowed on stream, and will result in IOErrorEnumPending errors.

A value of count larger than G_MAXSSIZE will cause a IOErrorEnumInvalidArgument error.

On success, the number of bytes read into the buffer will be passed to the callback. It is not an error if this is not the same as the requested size, as it can happen e.g. near the end of a file, but generally we try to read as many bytes as requested. Zero is returned on end of file (or if count is zero), but never otherwise.

Any outstanding i/o request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is PRIORITY_DEFAULT.

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.

readBytes

inputStreamReadBytes

Arguments

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

=> a

stream: a InputStream.

-> Word64

count: maximum number of bytes that will be read from the stream. Common values include 4096 and 8192.

-> Maybe b

cancellable: optional Cancellable object, Nothing to ignore.

-> m Bytes

Returns: a new Bytes, or Nothing on error (Can throw GError)

Like inputStreamRead, this tries to read count bytes from the stream in a blocking fashion. However, rather than reading into a user-supplied buffer, this will create a new Bytes containing the data that was read. This may be easier to use from language bindings.

If count is zero, returns a zero-length Bytes and does nothing. A value of count larger than G_MAXSSIZE will cause a IOErrorEnumInvalidArgument error.

On success, a new Bytes is returned. It is not an error if the size of this object is not the same as the requested size, as it can happen e.g. near the end of a file. A zero-length Bytes is returned on end of file (or if count is zero), but never otherwise.

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.

On error Nothing is returned and error is set accordingly.

Since: 2.34

readBytesAsync

inputStreamReadBytesAsync

Arguments

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

=> a

stream: A InputStream.

-> Word64

count: the number of bytes that will be read from the stream

-> Int32

ioPriority: the [I/O priority][io-priority] of the request

-> Maybe b

cancellable: optional Cancellable object, Nothing to ignore.

-> Maybe AsyncReadyCallback

callback: callback to call when the request is satisfied

-> m ()

Request an asynchronous read of count bytes from the stream into a new Bytes. When the operation is finished callback will be called. You can then call inputStreamReadBytesFinish to get the result of the operation.

During an async request no other sync and async calls are allowed on stream, and will result in IOErrorEnumPending errors.

A value of count larger than G_MAXSSIZE will cause a IOErrorEnumInvalidArgument error.

On success, the new Bytes will be passed to the callback. It is not an error if this is smaller than the requested size, as it can happen e.g. near the end of a file, but generally we try to read as many bytes as requested. Zero is returned on end of file (or if count is zero), but never otherwise.

Any outstanding I/O request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is PRIORITY_DEFAULT.

Since: 2.34

readBytesFinish

inputStreamReadBytesFinish

Arguments

:: (HasCallStack, MonadIO m, IsInputStream a, IsAsyncResult b)

=> a

stream: a InputStream.

-> b

result: a AsyncResult.

-> m Bytes

Returns: the newly-allocated Bytes, or Nothing on error (Can throw GError)

Finishes an asynchronous stream read-into-Bytes operation.

Since: 2.34

readFinish

inputStreamReadFinish

Arguments

:: (HasCallStack, MonadIO m, IsInputStream a, IsAsyncResult b)

=> a

stream: a InputStream.

-> b

result: a AsyncResult.

-> m Int64

Returns: number of bytes read in, or -1 on error, or 0 on end of file. (Can throw GError)

Finishes an asynchronous stream read operation.

setPending

inputStreamSetPending

Arguments

:: (HasCallStack, MonadIO m, IsInputStream a)

=> a

stream: input stream

-> m ()

(Can throw GError)

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

skip

inputStreamSkip

Arguments

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

=> a

stream: a InputStream.

-> Word64

count: the number of bytes that will be skipped from the stream

-> Maybe b

cancellable: optional Cancellable object, Nothing to ignore.

-> m Int64

Returns: Number of bytes skipped, or -1 on error (Can throw GError)

Tries to skip count bytes from the stream. Will block during the operation.

This is identical to inputStreamRead, from a behaviour standpoint, but the bytes that are skipped are not returned to the user. Some streams have an implementation that is more efficient than reading the data.

This function is optional for inherited classes, as the default implementation emulates it using read.

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.

skipAsync

inputStreamSkipAsync

Arguments

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

=> a

stream: A InputStream.

-> Word64

count: the number of bytes that will be skipped from the stream

-> Int32

ioPriority: the [I/O priority][io-priority] of the request

-> Maybe b

cancellable: optional Cancellable object, Nothing to ignore.

-> Maybe AsyncReadyCallback

callback: callback to call when the request is satisfied

-> m ()

Request an asynchronous skip of count bytes from the stream. When the operation is finished callback will be called. You can then call inputStreamSkipFinish to get the result of the operation.

During an async request no other sync and async calls are allowed, and will result in IOErrorEnumPending errors.

A value of count larger than G_MAXSSIZE will cause a IOErrorEnumInvalidArgument error.

On success, the number of bytes skipped will be passed to the callback. It is not an error if this is not the same as the requested size, as it can happen e.g. near the end of a file, but generally we try to skip as many bytes as requested. Zero is returned on end of file (or if count is zero), but never otherwise.

Any outstanding i/o request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is PRIORITY_DEFAULT.

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.

skipFinish

inputStreamSkipFinish

Arguments

:: (HasCallStack, MonadIO m, IsInputStream a, IsAsyncResult b)

=> a

stream: a InputStream.

-> b

result: a AsyncResult.

-> m Int64

Returns: the size of the bytes skipped, or %-1 on error. (Can throw GError)

Finishes a stream skip operation.