Class: Gio::InputStream

Inherits:
Object
  • Object
show all
Defined in:
(unknown)

Instance Method Summary collapse

Instance Method Details

#clear_pendingnil

Clears the pending flag on stream.

Returns:

  • (nil)

#close(cancellable) ⇒ TrueClass

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.

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.

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 some streams can use a faster close that doesn’t block to e.g. check errors.

Parameters:

  • cancellable (Gio::Cancellable)

    optional #GCancellable object, nil to ignore.

Returns:

  • (TrueClass)

    true on success, false on failure

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

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 g_input_stream_close_finish() to get the result of the operation.

For behaviour details see g_input_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 [I/O priority] of the request

  • cancellable (Gio::Cancellable)

    optional cancellable object

  • callback (Gio::AsyncReadyCallback)

    callback to call when the request is satisfied

  • user_data (GObject)

    the data to pass to callback function

Returns:

  • (nil)

#close_finish(result) ⇒ TrueClass

Finishes closing a stream asynchronously, started from g_input_stream_close_async().

Parameters:

Returns:

  • (TrueClass)

    true if the stream was closed successfully.

#has_pendingTrueClass

Checks if an input stream has pending actions.

Returns:

  • (TrueClass)

    true if stream has pending actions.

#is_closedTrueClass

Checks if an input stream is closed.

Returns:

  • (TrueClass)

    true if the stream is closed.

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

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 %G_IO_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.

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 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>)

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

  • count (Integer)

    the number of bytes that will be read from the stream

  • cancellable (Gio::Cancellable)

    optional #GCancellable object, nil to ignore.

Returns:

  • (Gio::gssize)

    Number of bytes read, or -1 on error, or 0 on end of file.

#read_all(buffer, count, bytes_read, cancellable) ⇒ TrueClass

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

This function is similar to g_input_stream_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 #GError, 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 g_input_stream_read().

Parameters:

  • buffer (Array<Integer>)

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

  • count (Integer)

    the number of bytes that will be read from the stream

  • bytes_read (Integer)

    location to store the number of bytes that was read from the stream

  • cancellable (Gio::Cancellable)

    optional #GCancellable object, nil to ignore.

Returns:

  • (TrueClass)

    true on success, false if there was an error

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

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

This is the asynchronous equivalent of g_input_stream_read_all().

Call g_input_stream_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 %G_PRIORITY_DEFAULT.

Parameters:

  • buffer (Array<Integer>)

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

  • count (Integer)

    the number of bytes that will be read from the stream

  • io_priority (Integer)

    the [I/O priority] of the request

  • cancellable (Gio::Cancellable)

    optional #GCancellable object, nil to ignore

  • callback (Gio::AsyncReadyCallback)

    callback to call when the request is satisfied

  • user_data (GObject)

    the data to pass to callback function

Returns:

  • (nil)

#read_all_finish(result, bytes_read) ⇒ TrueClass

Finishes an asynchronous stream read operation started with g_input_stream_read_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_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 g_input_stream_read_async().

Parameters:

  • result (Gio::AsyncResult)

    a GAsync::Result

  • bytes_read (Integer)

    location to store the number of bytes that was read from the stream

Returns:

  • (TrueClass)

    true on success, false if there was an error

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

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 g_input_stream_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 %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 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 %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. of the request.

Parameters:

  • buffer (Array<Integer>)

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

  • count (Integer)

    the number of bytes that will be read from the stream

  • io_priority (Integer)

    the [I/O priority]

  • cancellable (Gio::Cancellable)

    optional #GCancellable object, nil to ignore.

  • callback (Gio::AsyncReadyCallback)

    callback to call when the request is satisfied

  • user_data (GObject)

    the data to pass to callback function

Returns:

  • (nil)

#read_bytes(count, cancellable) ⇒ GLib::Bytes

Like g_input_stream_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 #GBytes containing the data that was read. This may be easier to use from language bindings.

If count is zero, returns a zero-length #GBytes and does nothing. A value of count larger than %G_MAXSSIZE will cause a %G_IO_ERROR_INVALID_ARGUMENT error.

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

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 nil is returned and error is set accordingly. values include 4096 and 8192.

Parameters:

  • count (Integer)

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

  • cancellable (Gio::Cancellable)

    optional #GCancellable object, nil to ignore.

Returns:

  • (GLib::Bytes)

    a new #GBytes, or nil on error

#read_bytes_async(count, io_priority, cancellable, callback, user_data) ⇒ nil

Request an asynchronous read of count bytes from the stream into a new #GBytes. When the operation is finished callback will be called. You can then call g_input_stream_read_bytes_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 %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 new #GBytes 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 %G_PRIORITY_DEFAULT.

Parameters:

  • count (Integer)

    the number of bytes that will be read from the stream

  • io_priority (Integer)

    the [I/O priority] of the request

  • cancellable (Gio::Cancellable)

    optional #GCancellable object, nil to ignore.

  • callback (Gio::AsyncReadyCallback)

    callback to call when the request is satisfied

  • user_data (GObject)

    the data to pass to callback function

Returns:

  • (nil)

#read_bytes_finish(result) ⇒ GLib::Bytes

Finishes an asynchronous stream read-into-#GBytes operation.

Parameters:

Returns:

  • (GLib::Bytes)

    the newly-allocated #GBytes, or nil on error

#read_finish(result) ⇒ Gio::gssize

Finishes an asynchronous stream read operation.

Parameters:

Returns:

  • (Gio::gssize)

    number of bytes read in, or -1 on error, or 0 on end of file.

#set_pendingTrueClass

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:

  • (TrueClass)

    true if pending was previously unset and is now set.

#skip(count, cancellable) ⇒ Gio::gssize

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

This is identical to g_input_stream_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 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.

Parameters:

  • count (Integer)

    the number of bytes that will be skipped from the stream

  • cancellable (Gio::Cancellable)

    optional #GCancellable object, nil to ignore.

Returns:

  • (Gio::gssize)

    Number of bytes skipped, or -1 on error

#skip_async(count, io_priority, cancellable, callback, user_data) ⇒ nil

Request an asynchronous skip of count bytes from the stream. When the operation is finished callback will be called. You can then call g_input_stream_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 %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 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 %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.

Parameters:

  • count (Integer)

    the number of bytes that will be skipped from the stream

  • io_priority (Integer)

    the [I/O priority] of the request

  • cancellable (Gio::Cancellable)

    optional #GCancellable object, nil to ignore.

  • callback (Gio::AsyncReadyCallback)

    callback to call when the request is satisfied

  • user_data (GObject)

    the data to pass to callback function

Returns:

  • (nil)

#skip_finish(result) ⇒ Gio::gssize

Finishes a stream skip operation.

Parameters:

Returns:

  • (Gio::gssize)

    the size of the bytes skipped, or ‘-1` on error.