writer_base Class Reference

Base class for all writers. More...

#include <writer.hpp>

Inheritance diagram for writer_base:

Collaboration diagram for writer_base:

Public Types
using	progress_cb_t = std::function< void(writer_base const *, uint64_t written)>
Public Types inherited from aio_base
using	size_type = uint64_t

Public Member Functions
	writer_base (writer_base const &)=delete
writer_base &	operator= (writer_base const &)=delete
virtual aio_result	preallocate (uint64_t)
	Instructs writer to preallocate storage. May be a noop.
aio_result	add_buffer (buffer_lease &&b, aio_waiter &h)
	Pass a buffer to be written out. More...
aio_result	add_buffer (buffer_lease &&b, event_handler &h)
aio_result	finalize (aio_waiter &h)
	Finalizes the writer. More...
aio_result	finalize (event_handler &h)
virtual bool	set_mtime (datetime const &)
	Must be finalized already.
void	close ()
Public Member Functions inherited from aio_waitable
void	remove_waiter (aio_waiter &h)
void	remove_waiter (event_handler &h)

Protected Member Functions
virtual aio_result	do_add_buffer (scoped_lock &l, buffer_lease &&b)=0
virtual aio_result	do_finalize (scoped_lock &l)=0
	writer_base (std::wstring &&name, aio_buffer_pool &pool, progress_cb_t &&progress_cb, size_t max_buffers) noexcept
	writer_base (std::wstring_view name, aio_buffer_pool &pool, progress_cb_t &&progress_cb, size_t max_buffers) noexcept
virtual void	do_close (scoped_lock &)
Protected Member Functions inherited from aio_waitable
void	remove_waiters ()
	Call in destructor of most-derived class.
void	add_waiter (aio_waiter &h)
void	add_waiter (event_handler &h)
void	signal_availibility ()

Protected Attributes
mutex	mtx_
aio_buffer_pool &	buffer_pool_
std::wstring const	name_
progress_cb_t	progress_cb_
size_t const	max_buffers_ {}
std::list< buffer_lease >	buffers_
bool	error_ {}
uint8_t	finalizing_ {}

Additional Inherited Members
Static Public Attributes inherited from aio_base
static constexpr auto	nosize = static_cast<size_type>(-1)

Detailed Description

Base class for all writers.

All writers have a name describing them for logging purposes.

The initial state of a freshly opened writer is writable, add_buffer() can be called.

See the aio demo program for example usage.

Examples

aio.cpp.

Member Typedef Documentation

progress_cb_t

using progress_cb_t = std::function<void(writer_base const*, uint64_t written)>

Progress callback is only for accounting progress. Never call into the writer from the callback.

The progress callback is invoked whenever the writer has written out some data.

Idiomatic usage of the the progress callback: Update some atomic variables and optionally send an event.

Member Function Documentation

add_buffer()

aio_result add_buffer	(	buffer_lease &&	b,
		aio_waiter &	h
	)

Pass a buffer to be written out.

If aio_result::ok is returned, you can call add_buffer again.

If aio_result::wait is returned, do not call add_buffer again until after the passed waiter got on_buffer_availability() invoked.

If aio_result::error is returned, the writer has failed and can only be closed.

finalize()

aio_result finalize

(

aio_waiter &

h

)

Finalizes the writer.

If aio_result::ok is returned, all pending data has been written out.

If aio_result::wait is returned, wait until the passed waiter gets on_buffer_availability() invoked, then call finalize again.

If aio_result::error is returned, the writer has failed and can only be closed.

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The documentation for this class was generated from the following file:

• writer.hpp