Gio.InputStream

g GObject.Object GObject.Object Gio.InputStream Gio.InputStream GObject.Object->Gio.InputStream

Subclasses:Gio.FileInputStream, Gio.FilterInputStream, Gio.MemoryInputStream, Gio.UnixInputStream

Methods

Inherited:GObject.Object (37)
Structs:GObject.ObjectClass (5)
  clear_pending ()
  close (cancellable)
  close_async (io_priority, cancellable, callback, *user_data)
  close_finish (result)
  has_pending ()
  is_closed ()
  read (cancellable)
  read_all (cancellable)
  read_all_async (io_priority, cancellable, callback, *user_data)
  read_all_finish (result)
  read_async (io_priority, cancellable, callback, *user_data)
  read_bytes (count, cancellable)
  read_bytes_async (count, io_priority, cancellable, callback, *user_data)
  read_bytes_finish (result)
  read_finish (result)
  set_pending ()
  skip (count, cancellable)
  skip_async (count, io_priority, cancellable, callback, *user_data)
  skip_finish (result)

Virtual Methods

Inherited:GObject.Object (7)
  do_close_async (io_priority, cancellable, callback, *user_data)
  do_close_finish (result)
  do_close_fn (cancellable)
  do_read_async (io_priority, cancellable, callback, *user_data)
  do_read_finish (result)
  do_read_fn (buffer, count, cancellable)
  do_skip (count, cancellable)
  do_skip_async (count, io_priority, cancellable, callback, *user_data)
  do_skip_finish (result)

Properties

None

Signals

Inherited:GObject.Object (1)

Fields

Inherited:GObject.Object (1)
Name Type Access Description
parent_instance GObject.Object r  
priv Gio.InputStreamPrivate r  

Class Details

class Gio.InputStream(**kwargs)
Bases:GObject.Object
Abstract:Yes
Structure:Gio.InputStreamClass

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

To copy the content of an input stream to an output stream without manually handling the reads and writes, use Gio.OutputStream.splice().

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

All of these functions have async variants too.

clear_pending()[source]

Clears the pending flag on self.

close(cancellable)[source]
Parameters:cancellable (Gio.Cancellable or None) – optional Gio.Cancellable object, None to ignore.
Raises:GLib.Error
Returns:True on success, False on failure
Return type:bool

Closes the stream, releasing resources related to it.

Once the stream is closed, all other operations will return Gio.IOErrorEnum.CLOSED. 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 Gio.IOErrorEnum.CLOSED for all operations. Still, it is important to check and report the error to the user.

If cancellable is not None, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error Gio.IOErrorEnum.CANCELLED 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.

close_async(io_priority, cancellable, callback, *user_data)[source]
Parameters:

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 Gio.InputStream.close_finish() to get the result of the operation.

For behaviour details see Gio.InputStream.close().

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.

close_finish(result)[source]
Parameters:result (Gio.AsyncResult) – a Gio.AsyncResult.
Raises:GLib.Error
Returns:True if the stream was closed successfully.
Return type:bool

Finishes closing a stream asynchronously, started from Gio.InputStream.close_async().

has_pending()[source]
Returns:True if self has pending actions.
Return type:bool

Checks if an input stream has pending actions.

is_closed()[source]
Returns:True if the stream is closed.
Return type:bool

Checks if an input stream is closed.

read(cancellable)[source]
Parameters:cancellable (Gio.Cancellable or None) – optional Gio.Cancellable object, None to ignore.
Raises:GLib.Error
Returns:Number of bytes read, or -1 on error, or 0 on end of file.
buffer:a buffer to read data into (which should be at least count bytes long).
Return type:(int, buffer: bytes)

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 GObject.G_MAXSSIZE will cause a Gio.IOErrorEnum.INVALID_ARGUMENT 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 None, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error Gio.IOErrorEnum.CANCELLED 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.

read_all(cancellable)[source]
Parameters:cancellable (Gio.Cancellable or None) – optional Gio.Cancellable object, None to ignore.
Raises:GLib.Error
Returns:True on success, False if there was an error
buffer:a buffer to read data into (which should be at least count bytes long).
bytes_read:location to store the number of bytes that was read from the stream
Return type:(bool, buffer: bytes, bytes_read: int)

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

This function is similar to Gio.InputStream.read(), 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 bytes_read 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 GLib.Error, if this function returns False (and sets error) then bytes_read 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 Gio.InputStream.read().

read_all_async(io_priority, cancellable, callback, *user_data)[source]
Parameters:
Returns:

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

Return type:

buffer: bytes

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

This is the asynchronous equivalent of Gio.InputStream.read_all().

Call Gio.InputStream.read_all_finish() 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 GLib.PRIORITY_DEFAULT.

New in version 2.44.

read_all_finish(result)[source]
Parameters:result (Gio.AsyncResult) – a Gio.AsyncResult
Raises:GLib.Error
Returns:True on success, False if there was an error
bytes_read:location to store the number of bytes that was read from the stream
Return type:(bool, bytes_read: int)

Finishes an asynchronous stream read operation started with Gio.InputStream.read_all_async().

As a special exception to the normal conventions for functions that use GLib.Error, if this function returns False (and sets error) then bytes_read 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 Gio.InputStream.read_async().

New in version 2.44.

read_async(io_priority, cancellable, callback, *user_data)[source]
Parameters:
Returns:

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

Return type:

buffer: bytes

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 Gio.InputStream.read_finish() to get the result of the operation.

During an async request no other sync and async calls are allowed on self, and will result in Gio.IOErrorEnum.PENDING errors.

A value of count larger than GObject.G_MAXSSIZE will cause a Gio.IOErrorEnum.INVALID_ARGUMENT 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 GLib.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.

read_bytes(count, cancellable)[source]
Parameters:
Raises:

GLib.Error

Returns:

a new GLib.Bytes, or None on error

Return type:

GLib.Bytes

Like Gio.InputStream.read(), 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 GLib.Bytes containing the data that was read. This may be easier to use from language bindings.

If count is zero, returns a zero-length GLib.Bytes and does nothing. A value of count larger than GObject.G_MAXSSIZE will cause a Gio.IOErrorEnum.INVALID_ARGUMENT error.

On success, a new GLib.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 GLib.Bytes is returned on end of file (or if count is zero), but never otherwise.

If cancellable is not None, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error Gio.IOErrorEnum.CANCELLED 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 None is returned and error is set accordingly.

New in version 2.34.

read_bytes_async(count, io_priority, cancellable, callback, *user_data)[source]
Parameters:

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

During an async request no other sync and async calls are allowed on self, and will result in Gio.IOErrorEnum.PENDING errors.

A value of count larger than GObject.G_MAXSSIZE will cause a Gio.IOErrorEnum.INVALID_ARGUMENT error.

On success, the new GLib.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 GLib.PRIORITY_DEFAULT.

New in version 2.34.

read_bytes_finish(result)[source]
Parameters:result (Gio.AsyncResult) – a Gio.AsyncResult.
Raises:GLib.Error
Returns:the newly-allocated GLib.Bytes, or None on error
Return type:GLib.Bytes

Finishes an asynchronous stream read-into-GLib.Bytes operation.

New in version 2.34.

read_finish(result)[source]
Parameters:result (Gio.AsyncResult) – a Gio.AsyncResult.
Raises:GLib.Error
Returns:number of bytes read in, or -1 on error, or 0 on end of file.
Return type:int

Finishes an asynchronous stream read operation.

set_pending()[source]
Raises:GLib.Error
Returns:True if pending was previously unset and is now set.
Return type:bool

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

skip(count, cancellable)[source]
Parameters:
Raises:

GLib.Error

Returns:

Number of bytes skipped, or -1 on error

Return type:

int

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

This is identical to Gio.InputStream.read(), 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 None, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error Gio.IOErrorEnum.CANCELLED will be returned. If an operation was partially finished when the operation was cancelled the partial result will be returned, without an error.

skip_async(count, io_priority, cancellable, callback, *user_data)[source]
Parameters:

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

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

A value of count larger than GObject.G_MAXSSIZE will cause a Gio.IOErrorEnum.INVALID_ARGUMENT 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 GLib.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.

skip_finish(result)[source]
Parameters:result (Gio.AsyncResult) – a Gio.AsyncResult.
Raises:GLib.Error
Returns:the size of the bytes skipped, or -1 on error.
Return type:int

Finishes a stream skip operation.

do_close_async(io_priority, cancellable, callback, *user_data) virtual
Parameters:

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 Gio.InputStream.close_finish() to get the result of the operation.

For behaviour details see Gio.InputStream.close().

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.

do_close_finish(result) virtual
Parameters:result (Gio.AsyncResult) – a Gio.AsyncResult.
Returns:True if the stream was closed successfully.
Return type:bool

Finishes closing a stream asynchronously, started from Gio.InputStream.close_async().

do_close_fn(cancellable) virtual
Parameters:cancellable (Gio.Cancellable or None) –
Return type:bool
do_read_async(io_priority, cancellable, callback, *user_data) virtual
Parameters:
Returns:

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

Return type:

buffer: bytes

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 Gio.InputStream.read_finish() 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 Gio.IOErrorEnum.PENDING errors.

A value of count larger than GObject.G_MAXSSIZE will cause a Gio.IOErrorEnum.INVALID_ARGUMENT 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 GLib.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.

do_read_finish(result) virtual
Parameters:result (Gio.AsyncResult) – a Gio.AsyncResult.
Returns:number of bytes read in, or -1 on error, or 0 on end of file.
Return type:int

Finishes an asynchronous stream read operation.

do_read_fn(buffer, count, cancellable) virtual
Parameters:
Return type:

int

do_skip(count, cancellable) virtual
Parameters:
Returns:

Number of bytes skipped, or -1 on error

Return type:

int

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

This is identical to Gio.InputStream.read(), 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 None, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error Gio.IOErrorEnum.CANCELLED will be returned. If an operation was partially finished when the operation was cancelled the partial result will be returned, without an error.

do_skip_async(count, io_priority, cancellable, callback, *user_data) virtual
Parameters:

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

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

A value of count larger than GObject.G_MAXSSIZE will cause a Gio.IOErrorEnum.INVALID_ARGUMENT 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 GLib.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.

do_skip_finish(result) virtual
Parameters:result (Gio.AsyncResult) – a Gio.AsyncResult.
Returns:the size of the bytes skipped, or -1 on error.
Return type:int

Finishes a stream skip operation.