2022-01-04 15:47:38 +02:00

120 lines
3.2 KiB
C++

/*
* Copyright (c) 2018 MariaDB Corporation Ab
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
*
* Change Date: 2026-01-04
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2 or later of the General
* Public License.
*/
#pragma once
/**
* @file include/maxscale/poll.hh - The public poll interface
*/
#include <maxscale/ccdefs.hh>
#include <maxscale/buffer.hh>
#include <maxscale/dcb.hh>
MXS_BEGIN_DECLS
/**
* A statistic identifier that can be returned by poll_get_stat
*/
typedef enum
{
POLL_STAT_READ,
POLL_STAT_WRITE,
POLL_STAT_ERROR,
POLL_STAT_HANGUP,
POLL_STAT_ACCEPT,
POLL_STAT_EVQ_AVG,
POLL_STAT_EVQ_MAX,
POLL_STAT_MAX_QTIME,
POLL_STAT_MAX_EXECTIME
} POLL_STAT;
/*
* Return a particular statistics value.
*
* @param stat What to return.
*
* @return The value.
*/
int64_t poll_get_stat(POLL_STAT stat);
/*
* Insert a fake hangup event for a DCB into the polling queue.
*
* This is used when a monitor detects that a server is not responding.
*
* @param dcb DCB to emulate an EPOLLOUT event for
*/
void poll_fake_hangup_event(DCB* dcb);
/*
* Insert a fake write completion event for a DCB into the polling
* queue.
*
* This is used to trigger transmission activity on another DCB from
* within the event processing routine of a DCB. or to allow a DCB
* to defer some further output processing, to allow for other DCBs
* to receive a slice of the processing time. Fake events are added
* to the tail of the event queue, in the same way that real events
* are, so maintain the "fairness" of processing.
*
* @param dcb DCB to emulate an EPOLLOUT event for
*/
void poll_fake_write_event(DCB* dcb);
/*
* Insert a fake read completion event for a DCB into the polling
* queue.
*
* This is used to trigger transmission activity on another DCB from
* within the event processing routine of a DCB. or to allow a DCB
* to defer some further input processing, to allow for other DCBs
* to receive a slice of the processing time. Fake events are added
* to the tail of the event queue, in the same way that real events
* are, so maintain the "fairness" of processing.
*
* @param dcb DCB to emulate an EPOLLIN event for
*/
void poll_fake_read_event(DCB* dcb);
/**
* Add a DCB to the set of descriptors within the polling
* environment.
*
* @param dcb The descriptor to add to the poll
* @return -1 on error or 0 on success
*/
int poll_add_dcb(DCB*);
/**
* Remove a descriptor from the set of descriptors within the
* polling environment.
*
* @param dcb The descriptor to remove
* @return -1 on error or 0 on success; actually always 0
*/
int poll_remove_dcb(DCB*);
/**
* Add given GWBUF to DCB's readqueue and add a pending EPOLLIN event for DCB.
* The event pretends that there is something to read for the DCB. Actually
* the incoming data is stored in the DCB's readqueue where it is read.
*
* @param dcb DCB where the event and data are added
* @param buf GWBUF including the data
*
*/
void poll_add_epollin_event_to_dcb(DCB* dcb, GWBUF* buf);
MXS_END_DECLS