Class: Gio::OutputStream

Inherits:
Object
  • Object
show all
Defined in:
lib/gio2/output-stream.rb

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.open(*arguments) ⇒ Object 



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# File 'lib/gio2/output-stream.rb', line 20

def open(*arguments)
  output_stream = new(*arguments)
  return output_stream unless block_given?

  begin
    yield(output_stream)
  ensure
    output_stream.close unless output_stream.closed?
  end
end

Instance Method Details

#clear_pending ⇒ nil

Clears the pending flag on stream.

Returns:

  • (nil)

#close(cancellable) ⇒ Boolean

Closes the stream, releasing resources related to it.

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

Closing a stream will automatically flush any outstanding buffers in the
stream.

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 %G_IO_ERROR_CLOSED for all operations. Still, it
is important to check and report the error to the user, otherwise
there might be a loss of data as all data might not be written.

If cancellable is not nil, then the operation can be cancelled by
triggering the cancellable object from another thread. If the operation
was cancelled, the error %G_IO_ERROR_CANCELLED will be returned.
Cancelling a close will still leave the stream closed, but there some streams
can use a faster close that doesn't block to e.g. check errors. On
cancellation (as with any error) there is no guarantee that all written
data will reach the target.

Parameters:

Returns:

  • (Boolean) —

    true on success, false on failure

#close_async(io_priority, cancellable, callback, user_data) ⇒ nil

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

For behaviour details see g_output_stream_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.

Parameters:

  • io_priority (Integer) —

    the io priority of the request.

  • cancellable (Gio::Cancellable) —

    optional cancellable object

  • callback (Gio::AsyncReadyCallback) —

    a GAsync::ReadyCallback
    to call when the request is satisfied

  • user_data (GObject) —

    the data to pass to callback function

Returns:

  • (nil)

#close_finish(result) ⇒ Boolean

Closes an output stream.

Parameters:

Returns:

  • (Boolean) —

    true if stream was successfully closed, false otherwise.

#flush(cancellable) ⇒ Boolean

Forces a write of all user-space buffered data for the given
stream. Will block during the operation. Closing the stream will
implicitly cause a flush.

This function is optional for inherited classes.

If cancellable is not nil, then the operation can be cancelled by
triggering the cancellable object from another thread. If the operation
was cancelled, the error %G_IO_ERROR_CANCELLED will be returned.

Parameters:

Returns:

  • (Boolean) —

    true on success, false on error

#flush_async(io_priority, cancellable, callback, user_data) ⇒ nil

Forces an asynchronous write of all user-space buffered data for
the given stream.
For behaviour details see g_output_stream_flush().

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

Parameters:

  • io_priority (Integer) —

    the io priority of the request.

  • cancellable (Gio::Cancellable) —

    optional #GCancellable object, nil to ignore.

  • callback (Gio::AsyncReadyCallback) —

    a GAsync::ReadyCallback
    to call when the request is satisfied

  • user_data (GObject) —

    the data to pass to callback function

Returns:

  • (nil)

#flush_finish(result) ⇒ Boolean

Finishes flushing an output stream.

Parameters:

Returns:

  • (Boolean) —

    true if flush operation succeeded, false otherwise.

#has_pending ⇒ Boolean

Checks if an output stream has pending actions.

Returns:

  • (Boolean) —

    true if stream has pending actions.

#is_closed ⇒ Boolean

Checks if an output stream has already been closed.

Returns:

  • (Boolean) —

    true if stream is closed. false otherwise.

#is_closing ⇒ Boolean

Checks if an output stream is being closed. This can be
used inside e.g. a flush implementation to see if the
flush (or other i/o operation) is called from within
the closing operation.

Returns:

  • (Boolean) —

    true if stream is being closed. false otherwise.

#printf(bytes_written, cancellable, error, format, array) ⇒ Boolean

This is a utility function around g_output_stream_write_all(). It
uses g_strdup_vprintf() to turn format and @... into a string that
is then written to stream.

See the documentation of g_output_stream_write_all() about the
behavior of the actual write operation.

Note that partial writes cannot be properly checked with this
function due to the variable length of the written string, if you
need precise control over partial write failures, you need to
create you own printf()-like wrapper around g_output_stream_write()
or g_output_stream_write_all().

Parameters:

  • bytes_written (Integer) —

    location to store the number of bytes that was
    written to the stream

  • cancellable (Gio::Cancellable) —

    optional #GCancellable object, nil to ignore.

  • error (GLib::Error) —

    location to store the error occurring, or nil to ignore

  • format (String) —

    the format string. See the printf() documentation

  • array (Array) —

    the parameters to insert into the format string

Returns:

  • (Boolean) —

    true on success, false if there was an error

#set_pending ⇒ Boolean

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

Returns:

  • (Boolean) —

    true if pending was previously unset and is now set.

#splice(source, flags, cancellable) ⇒ Gio::gssize

Splices an input stream into an output stream.

Parameters:

Returns:

  • (Gio::gssize) —

    a #gssize containing the size of the data spliced, or
    -1 if an error occurred. Note that if the number of bytes
    spliced is greater than %G_MAXSSIZE, then that will be
    returned, and there is no way to determine the actual number
    of bytes spliced.

#splice_async(source, flags, io_priority, cancellable, callback, user_data) ⇒ nil

Splices a stream asynchronously.
When the operation is finished callback will be called.
You can then call g_output_stream_splice_finish() to get the
result of the operation.

For the synchronous, blocking version of this function, see
g_output_stream_splice().

Parameters:

  • source (Gio::InputStream) —

    a GInput::Stream.

  • flags (Gio::OutputStreamSpliceFlags) —

    a set of GOutput::StreamSpliceFlags.

  • io_priority (Integer) —

    the io priority of the request.

  • cancellable (Gio::Cancellable) —

    optional #GCancellable object, nil to ignore.

  • callback (Gio::AsyncReadyCallback) —

    a GAsync::ReadyCallback
    to call when the request is satisfied

  • user_data (GObject) —

    the data to pass to callback function

Returns:

  • (nil)

#splice_finish(result) ⇒ Gio::gssize

Finishes an asynchronous stream splice operation.

Parameters:

Returns:

  • (Gio::gssize) —

    a #gssize of the number of bytes spliced. Note that if the
    number of bytes spliced is greater than %G_MAXSSIZE, then that
    will be returned, and there is no way to determine the actual
    number of bytes spliced.

#vprintf(bytes_written, cancellable, error, format, args) ⇒ Boolean

This is a utility function around g_output_stream_write_all(). It
uses g_strdup_vprintf() to turn format and args into a string that
is then written to stream.

See the documentation of g_output_stream_write_all() about the
behavior of the actual write operation.

Note that partial writes cannot be properly checked with this
function due to the variable length of the written string, if you
need precise control over partial write failures, you need to
create you own printf()-like wrapper around g_output_stream_write()
or g_output_stream_write_all().

Parameters:

  • bytes_written (Integer) —

    location to store the number of bytes that was
    written to the stream

  • cancellable (Gio::Cancellable) —

    optional #GCancellable object, nil to ignore.

  • error (GLib::Error) —

    location to store the error occurring, or nil to ignore

  • format (String) —

    the format string. See the printf() documentation

  • args (Gio::va_list) —

    the parameters to insert into the format string

Returns:

  • (Boolean) —

    true on success, false if there was an error

#write(buffer, count, cancellable) ⇒ Gio::gssize

Tries to write count bytes from buffer into the stream. Will block
during the operation.

If count is 0, returns 0 and does nothing. A value of count
larger than %G_MAXSSIZE will cause a %G_IO_ERROR_INVALID_ARGUMENT error.

On success, the number of bytes written to the stream is returned.
It is not an error if this is not the same as the requested size, as it
can happen e.g. on a partial I/O error, or if there is not enough
storage in the stream. All writes block until at least one byte
is written or an error occurs; 0 is never returned (unless
count is 0).

If cancellable is not nil, then the operation can be cancelled by
triggering the cancellable object from another thread. If the operation
was cancelled, the error %G_IO_ERROR_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.

Parameters:

  • buffer (Array<Integer>) —

    the buffer containing the data to write.

  • count (Integer) —

    the number of bytes to write

  • cancellable (Gio::Cancellable) —

    optional cancellable object

Returns:

  • (Gio::gssize) —

    Number of bytes written, or -1 on error

#write_all(buffer, count, bytes_written, cancellable) ⇒ Boolean

Tries to write count bytes from buffer into the stream. Will block
during the operation.

This function is similar to g_output_stream_write(), except it tries to
write as many bytes as requested, only stopping on an error.

On a successful write of count bytes, true is returned, and bytes_written
is set to count.

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
bytes_written will be set to the number of bytes that were
successfully written 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
g_output_stream_write().

Parameters:

  • buffer (Array<Integer>) —

    the buffer containing the data to write.

  • count (Integer) —

    the number of bytes to write

  • bytes_written (Integer) —

    location to store the number of bytes that was
    written to the stream

  • cancellable (Gio::Cancellable) —

    optional #GCancellable object, nil to ignore.

Returns:

  • (Boolean) —

    true on success, false if there was an error

#write_all_async(buffer, count, io_priority, cancellable, callback, user_data) ⇒ nil

Request an asynchronous write of count bytes from buffer into
the stream. When the operation is finished callback will be called.
You can then call g_output_stream_write_all_finish() to get the result of the
operation.

This is the asynchronous version of g_output_stream_write_all().

Call g_output_stream_write_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 %G_PRIORITY_DEFAULT.

Note that no copy of buffer will be made, so it must stay valid
until callback is called.

Parameters:

  • buffer (Array<Integer>) —

    the buffer containing the data to write

  • count (Integer) —

    the number of bytes to write

  • io_priority (Integer) —

    the io priority of the request

  • cancellable (Gio::Cancellable) —

    optional #GCancellable object, nil to ignore

  • callback (Gio::AsyncReadyCallback) —

    a GAsync::ReadyCallback
    to call when the request is satisfied

  • user_data (GObject) —

    the data to pass to callback function

Returns:

  • (nil)

#write_all_finish(result, bytes_written) ⇒ Boolean

Finishes an asynchronous stream write operation started with
g_output_stream_write_all_async().

As a special exception to the normal conventions for functions that
use #GError, if this function returns false (and sets error) then
bytes_written will be set to the number of bytes that were
successfully written 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
g_output_stream_write_async().

Parameters:

  • result (Gio::AsyncResult) —

    a GAsync::Result

  • bytes_written (Integer) —

    location to store the number of bytes that was written to the stream

Returns:

  • (Boolean) —

    true on success, false if there was an error

#write_async(buffer, count, io_priority, cancellable, callback, user_data) ⇒ nil

Request an asynchronous write of count bytes from buffer into
the stream. When the operation is finished callback will be called.
You can then call g_output_stream_write_finish() to get the result of the
operation.

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

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

On success, the number of bytes written 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. on a partial I/O error,
but generally we try to write as many bytes as requested.

You are guaranteed that this method will never fail with
%G_IO_ERROR_WOULD_BLOCK - if stream can't accept more data, the
method will just wait until this changes.

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

For the synchronous, blocking version of this function, see
g_output_stream_write().

Note that no copy of buffer will be made, so it must stay valid
until callback is called. See g_output_stream_write_bytes_async()
for a #GBytes version that will automatically hold a reference to
the contents (without copying) for the duration of the call.

Parameters:

  • buffer (Array<Integer>) —

    the buffer containing the data to write.

  • count (Integer) —

    the number of bytes to write

  • io_priority (Integer) —

    the io priority of the request.

  • cancellable (Gio::Cancellable) —

    optional #GCancellable object, nil to ignore.

  • callback (Gio::AsyncReadyCallback) —

    a GAsync::ReadyCallback
    to call when the request is satisfied

  • user_data (GObject) —

    the data to pass to callback function

Returns:

  • (nil)

#write_bytes(bytes, cancellable) ⇒ Gio::gssize

A wrapper function for g_output_stream_write() which takes a
#GBytes as input. This can be more convenient for use by language
bindings or in other cases where the refcounted nature of #GBytes
is helpful over a bare pointer interface.

However, note that this function may still perform partial writes,
just like g_output_stream_write(). If that occurs, to continue
writing, you will need to create a new #GBytes containing just the
remaining bytes, using g_bytes_new_from_bytes(). Passing the same
#GBytes instance multiple times potentially can result in duplicated
data in the output stream.

Parameters:

  • bytes (GLib::Bytes) —

    the #GBytes to write

  • cancellable (Gio::Cancellable) —

    optional cancellable object

Returns:

  • (Gio::gssize) —

    Number of bytes written, or -1 on error

#write_bytes_async(bytes, io_priority, cancellable, callback, user_data) ⇒ nil

This function is similar to g_output_stream_write_async(), but
takes a #GBytes as input. Due to the refcounted nature of #GBytes,
this allows the stream to avoid taking a copy of the data.

However, note that this function may still perform partial writes,
just like g_output_stream_write_async(). If that occurs, to continue
writing, you will need to create a new #GBytes containing just the
remaining bytes, using g_bytes_new_from_bytes(). Passing the same
#GBytes instance multiple times potentially can result in duplicated
data in the output stream.

For the synchronous, blocking version of this function, see
g_output_stream_write_bytes().

Parameters:

  • bytes (GLib::Bytes) —

    The bytes to write

  • io_priority (Integer) —

    the io priority of the request.

  • cancellable (Gio::Cancellable) —

    optional #GCancellable object, nil to ignore.

  • callback (Gio::AsyncReadyCallback) —

    a GAsync::ReadyCallback
    to call when the request is satisfied

  • user_data (GObject) —

    the data to pass to callback function

Returns:

  • (nil)

#write_bytes_finish(result) ⇒ Gio::gssize

Finishes a stream write-from-#GBytes operation.

Parameters:

Returns:

  • (Gio::gssize) —

    a #gssize containing the number of bytes written to the stream.

#write_finish(result) ⇒ Gio::gssize

Finishes a stream write operation.

Parameters:

Returns:

  • (Gio::gssize) —

    a #gssize containing the number of bytes written to the stream.

#writev(vectors, n_vectors, bytes_written, cancellable) ⇒ Boolean

Tries to write the bytes contained in the n_vectors vectors into the
stream. Will block during the operation.

If n_vectors is 0 or the sum of all bytes in vectors is 0, returns 0 and
does nothing.

On success, the number of bytes written to the stream is returned.
It is not an error if this is not the same as the requested size, as it
can happen e.g. on a partial I/O error, or if there is not enough
storage in the stream. All writes block until at least one byte
is written or an error occurs; 0 is never returned (unless
n_vectors is 0 or the sum of all bytes in vectors is 0).

If cancellable is not nil, then the operation can be cancelled by
triggering the cancellable object from another thread. If the operation
was cancelled, the error %G_IO_ERROR_CANCELLED will be returned. If an
operation was partially finished when the operation was cancelled the
partial result will be returned, without an error.

Some implementations of g_output_stream_writev() may have limitations on the
aggregate buffer size, and will return %G_IO_ERROR_INVALID_ARGUMENT if these
are exceeded. For example, when writing to a local file on UNIX platforms,
the aggregate buffer size must not exceed %G_MAXSSIZE bytes.

Parameters:

  • vectors (Array<Gio::OutputVector>) —

    the buffer containing the GOutput::Vectors to write.

  • n_vectors (Integer) —

    the number of vectors to write

  • bytes_written (Integer) —

    location to store the number of bytes that were
    written to the stream

  • cancellable (Gio::Cancellable) —

    optional cancellable object

Returns:

  • (Boolean) —

    true on success, false if there was an error

#writev_all(vectors, n_vectors, bytes_written, cancellable) ⇒ Boolean

Tries to write the bytes contained in the n_vectors vectors into the
stream. Will block during the operation.

This function is similar to g_output_stream_writev(), except it tries to
write as many bytes as requested, only stopping on an error.

On a successful write of all n_vectors vectors, true is returned, and
bytes_written is set to the sum of all the sizes of vectors.

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
bytes_written will be set to the number of bytes that were
successfully written 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
g_output_stream_write().

The content of the individual elements of vectors might be changed by this
function.

Parameters:

  • vectors (Array<Gio::OutputVector>) —

    the buffer containing the GOutput::Vectors to write.

  • n_vectors (Integer) —

    the number of vectors to write

  • bytes_written (Integer) —

    location to store the number of bytes that were
    written to the stream

  • cancellable (Gio::Cancellable) —

    optional #GCancellable object, nil to ignore.

Returns:

  • (Boolean) —

    true on success, false if there was an error

#writev_all_async(vectors, n_vectors, io_priority, cancellable, callback, user_data) ⇒ nil

Request an asynchronous write of the bytes contained in the n_vectors vectors into
the stream. When the operation is finished callback will be called.
You can then call g_output_stream_writev_all_finish() to get the result of the
operation.

This is the asynchronous version of g_output_stream_writev_all().

Call g_output_stream_writev_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 %G_PRIORITY_DEFAULT.

Note that no copy of vectors will be made, so it must stay valid
until callback is called. The content of the individual elements
of vectors might be changed by this function.

Parameters:

  • vectors (Array<Gio::OutputVector>) —

    the buffer containing the GOutput::Vectors to write.

  • n_vectors (Integer) —

    the number of vectors to write

  • io_priority (Integer) —

    the I/O priority of the request

  • cancellable (Gio::Cancellable) —

    optional #GCancellable object, nil to ignore

  • callback (Gio::AsyncReadyCallback) —

    a GAsync::ReadyCallback
    to call when the request is satisfied

  • user_data (GObject) —

    the data to pass to callback function

Returns:

  • (nil)

#writev_all_finish(result, bytes_written) ⇒ Boolean

Finishes an asynchronous stream write operation started with
g_output_stream_writev_all_async().

As a special exception to the normal conventions for functions that
use #GError, if this function returns false (and sets error) then
bytes_written will be set to the number of bytes that were
successfully written 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
g_output_stream_writev_async().

Parameters:

  • result (Gio::AsyncResult) —

    a GAsync::Result

  • bytes_written (Integer) —

    location to store the number of bytes that were written to the stream

Returns:

  • (Boolean) —

    true on success, false if there was an error

#writev_async(vectors, n_vectors, io_priority, cancellable, callback, user_data) ⇒ nil

Request an asynchronous write of the bytes contained in n_vectors vectors into
the stream. When the operation is finished callback will be called.
You can then call g_output_stream_writev_finish() to get the result of the
operation.

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

On success, the number of bytes written 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. on a partial I/O error,
but generally we try to write as many bytes as requested.

You are guaranteed that this method will never fail with
%G_IO_ERROR_WOULD_BLOCK — if stream can't accept more data, the
method will just wait until this changes.

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

For the synchronous, blocking version of this function, see
g_output_stream_writev().

Note that no copy of vectors will be made, so it must stay valid
until callback is called.

Parameters:

  • vectors (Array<Gio::OutputVector>) —

    the buffer containing the GOutput::Vectors to write.

  • n_vectors (Integer) —

    the number of vectors to write

  • io_priority (Integer) —

    the I/O priority of the request.

  • cancellable (Gio::Cancellable) —

    optional #GCancellable object, nil to ignore.

  • callback (Gio::AsyncReadyCallback) —

    a GAsync::ReadyCallback
    to call when the request is satisfied

  • user_data (GObject) —

    the data to pass to callback function

Returns:

  • (nil)

#writev_finish(result, bytes_written) ⇒ Boolean

Finishes a stream writev operation.

Parameters:

  • result (Gio::AsyncResult) —

    a GAsync::Result.

  • bytes_written (Integer) —

    location to store the number of bytes that were written to the stream

Returns:

  • (Boolean) —

    true on success, false if there was an error