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/* Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*!
* \file fdset.h
*
* \author Marek Vavrusa <marek.vavrusa@nic.cz>
*
* \brief Wrapper for native I/O multiplexing.
*
* Selects best implementation according to config.
* - select()
* - poll() \todo
* - epoll()
* - kqueue()
*
* \addtogroup common_lib
* @{
*/
#ifndef _KNOTD_FDSET_H_
#define _KNOTD_FDSET_H_
#include <stddef.h>
/*! \brief Opaque pointer to implementation-specific fdset data. */
typedef struct fdset_t fdset_t;
/*! \brief Unified event types. */
enum fdset_event_t {
OS_EV_READ = 1 << 0, /*!< Readable event. */
OS_EV_WRITE = 1 << 1, /*!< Writeable event. */
OS_EV_ERROR = 1 << 2 /*!< Error event. */
};
/*! \brief File descriptor set iterator. */
typedef struct fdset_it_t {
int fd; /*!< Current file descriptor. */
int events; /*!< Returned events. */
size_t pos; /* Internal usage. */
} fdset_it_t;
/*!
* \brief File descriptor set implementation backend.
* \notice Functions documentation following.
* \internal
*/
struct fdset_backend_t
{
fdset_t* (*fdset_new)();
int (*fdset_destroy)(fdset_t*);
int (*fdset_add)(fdset_t*, int, int);
int (*fdset_remove)(fdset_t*, int);
int (*fdset_wait)(fdset_t*);
int (*fdset_begin)(fdset_t*, fdset_it_t*);
int (*fdset_end)(fdset_t*, fdset_it_t*);
int (*fdset_next)(fdset_t*, fdset_it_t*);
const char* (*fdset_method)();
};
/*!
* \brief Selected backend.
* \internal
*/
extern struct fdset_backend_t _fdset_backend;
/*!
* \brief Create new fdset.
*
* FDSET implementation depends on system.
*
* \retval Pointer to initialized FDSET structure if successful.
* \retval NULL on error.
*/
static inline fdset_t *fdset_new() {
return _fdset_backend.fdset_new();
}
/*!
* \brief Destroy FDSET.
*
* \retval 0 if successful.
* \retval -1 on error.
*/
static inline int fdset_destroy(fdset_t * fdset) {
return _fdset_backend.fdset_destroy(fdset);
}
/*!
* \brief Add file descriptor to watched set.
*
* \param fdset Target set.
* \param fd Added file descriptor.
* \param events Mask of watched events.
*
* \retval 0 if successful.
* \retval -1 on errors.
*/
static inline int fdset_add(fdset_t *fdset, int fd, int events) {
return _fdset_backend.fdset_add(fdset, fd, events);
}
/*!
* \brief Remove file descriptor from watched set.
*
* \param fdset Target set.
* \param fd File descriptor to be removed.
*
* \retval 0 if successful.
* \retval -1 on errors.
*/
static inline int fdset_remove(fdset_t *fdset, int fd) {
return _fdset_backend.fdset_remove(fdset, fd);
}
/*!
* \brief Poll set for new events.
*
* \param fdset Target set.
*
* \retval Number of events if successful.
* \retval -1 on errors.
*
* \todo Timeout.
*/
static inline int fdset_wait(fdset_t *fdset) {
return _fdset_backend.fdset_wait(fdset);
}
/*!
* \brief Set event iterator to the beginning of last polled events.
*
* \param fdset Target set.
* \param it Event iterator.
*
* \retval 0 if successful.
* \retval -1 on errors.
*/
static inline int fdset_begin(fdset_t *fdset, fdset_it_t *it) {
return _fdset_backend.fdset_begin(fdset, it);
}
/*!
* \brief Set event iterator to the end of last polled events.
*
* \param fdset Target set.
* \param it Event iterator.
*
* \retval 0 if successful.
* \retval -1 on errors.
*/
static inline int fdset_end(fdset_t *fdset, fdset_it_t *it) {
return _fdset_backend.fdset_end(fdset, it);
}
/*!
* \brief Set event iterator to the next event.
*
* Event iterator fd will be set to -1 if next event doesn't exist.
*
* \param fdset Target set.
* \param it Event iterator.
*
* \retval 0 if successful.
* \retval -1 on errors.
*/
static inline int fdset_next(fdset_t *fdset, fdset_it_t *it) {
return _fdset_backend.fdset_next(fdset, it);
}
/*!
* \brief Returned name of underlying poll method.
*
* \retval Name if successful.
* \retval NULL if no method was loaded (shouldn't happen).
*/
static inline const char* fdset_method() {
return _fdset_backend.fdset_method();
}
#endif /* _KNOTD_FDSET_H_ */
/*! @} */
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