gio.InputStream
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gio.InputStream

gio.InputStream — Base class for implementing streaming input

Synopsis

class gio.InputStream(gobject.GObject):
    def clear_pending()
    def close(cancellable=None)
    def close_async(callback, io_priority=glib.PRIORITY_DEFAULT, cancellable=None, user_data=None)
    def close_finish(result)
    def has_pending()
    def is_closed()
    def read(count=-1, cancellable=None)
    def read_async(count, callback, io_priority=glib.PRIORITY_DEFAULT, cancellable=None, user_data=None)
    def read_finish(result)
    def read_part(count=-1, cancellable=None)
    def set_pending()
    def skip(count, cancellable=None)
    def skip_async(count, callback, io_priority=glib.PRIORITY_DEFAULT, cancellable=None, user_data=None)
    def skip_finish(result)

Ancestry

+-- gobject.GObject
  +-- gio.InputStream

Description

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().

All of these functions have async variants too.

Methods

gio.InputStream.clear_pending

    def clear_pending()

The clear_pending() method clears the pending flag on stream.

gio.InputStream.close

    def close(cancellable=None)

cancellable :

optional gio.Cancellable object, None to ignore.

Returns :

True on success False on failure.

The close() method closes the stream, releasing resources related to it.

Once the stream is closed, all other operations will return gio.ERROR_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.ERROR_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.ERROR_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.

gio.InputStream.close_async

    def close_async(callback, io_priority=glib.PRIORITY_DEFAULT, cancellable=None, user_data=None)

callback :

a GAsyncReadyCallback to call when the request is satisfied.

io_priority :

the Glib Priority Constants of the request.

cancellable :

optional gio.Cancellable object, None to ignore.

user_data :

the data to pass to callback function.

The close_async() method asynchronously requests an asynchronous closes of the stream, releasing resources related to it.

For more details, see gio.InputStream.close() which is the synchronous version of this call.

When the operation is finished, callback will be called. You can then call gio.InputStream.close_finish() to get the result of the operation.

gio.InputStream.close_finish

    def close_finish(result)

result :

a gio.AsyncResult.

Returns :

True if the stream was closed successfully.

The close_finish() method finishes an asynchronous file append operation started with gio.InputStream.close_async().

gio.InputStream.has_pending

    def has_pending()

Returns :

True if stream has pending actions.

The has_pending() method checks if an input stream has pending actions.

gio.InputStream.is_closed

    def is_closed()

Returns :

True if the stream is closed.

The is_closed() method checks if an input stream is closed.

gio.InputStream.read

    def read(count=-1, cancellable=None)

count :

optionally the number of bytes that will be read from the stream.

cancellable :

optional gio.Cancellable object, None to ignore.

Returns :

The number of bytes read, or -1 on error.

The read() method 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_part(), 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 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.ERROR_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.

If there is an error during the operation False is returned and error is set to indicate the error status, bytes_read is updated to contain the number of bytes read into buffer before the error occurred.

gio.InputStream.read_async

    def read_async(count, callback, io_priority=glib.PRIORITY_DEFAULT, cancellable=None, user_data=None)

count :

the number of bytes that will be read from the stream.

callback :

a GAsyncReadyCallback to call when the request is satisfied.

io_priority :

the Glib Priority Constants of the request.

cancellable :

optional gio.Cancellable object, None to ignore.

user_data :

the data to pass to callback function.

The read_async() method requests an asynchronous read of count bytes from the stream into the buffer.

For more details, see gio.InputStream.read() which is the synchronous version of this call.

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, and will result in gio.ERROR_PENDING errors.

A value of count larger than G_MAXSSIZE will cause a gio.ERROR_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 asyncronous 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.

gio.InputStream.read_finish

    def read_finish(result)

result :

a gio.AsyncResult.

Returns :

The number of bytes read in, or -1 on error.

The read_finish() method finishes an asynchronous stream read operation started by gio.InputStream.read_async().

gio.InputStream.read_part

    def read_part(count=-1, cancellable=None)

count :

optionally the number of bytes that will be read from the stream.

cancellable :

optional gio.Cancellable object, None to ignore.

Returns :

The number of bytes read, or -1 on error.

The read_part() method 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 gio.ERROR_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.

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.ERROR_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.

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

Note

This method roughly corresponds to C GIO g_input_stream_read.

gio.InputStream.set_pending

    def set_pending()

Returns :

True if pending was previously unset and is now set.

The set_pending() method sets stream to have actions pending. If the pending flag is already set or stream is closed, it will return False and set error.

gio.InputStream.skip

    def skip(count, cancellable=None)

count :

the number of bytes that will be skipped from the stream.

cancellable :

optional gio.Cancellable object, None to ignore.

Returns :

The number of bytes skipped, or -1 on error

The skip() method tries to skip count bytes from the stream. Will block during the operation.

This is identical to 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 thskip. If the operation was cancelled, the error gio.ERROR_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.

gio.InputStream.skip_async

    def skip_async(count, callback, io_priority=glib.PRIORITY_DEFAULT, cancellable=None, user_data=None)

count :

the number of bytes that will be skipped from the stream.

callback :

a GAsyncskipyCallback to call when the request is satisfied.

io_priority :

the Glib Priority Constants of the request.

cancellable :

optional gio.Cancellable object, None to ignore.

user_data :

the data to pass to callback function.

The skip_async() method request an asynchronous skip of count bytes from the stream.

For more details, see gio.InputStream.skip() which is the synchronous version of this call.

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.ERROR_PENDING errors.

A value of count larger than G_MAXSSIZE will cause a gio.ERROR_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 asyncronous methods have a default fallback that uses thskips to implement asynchronicity, so they are optional for inheriting classes. However, if you override one you must override all.

gio.InputStream.skip_finish

    def skip_finish(result)

result :

a gio.AsyncResult.

Returns :

The number of bytes skipped in, or -1 on error.

The skip_finish() method finishes an asynchronous stream skip operation started by gio.InputStream.skip_async().

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