Feature #17059 » epoll.h

WIP backend - dsh0416 (Delton Ding), 07/29/2020 03:55 PM

#ifndef RBIMPL_INTERN_SELECT_EPOLL_H /*-*-C++-*-vi:se ft=cpp:*/
* @file
* @author Ruby developers <>
* @copyright This file is a part of the programming language Ruby.
* Permission is hereby granted, to either redistribute and/or
* modify this file, provided that the conditions mentioned in the
* file COPYING are met. Consult the file for details.
* @warning Symbols prefixed with either `RBIMPL` or `rbimpl` are
* implementation details. Don't take them as canon. They could
* rapidly appear then vanish. The name (path) of this header file
* is also an implementation detail. Do not expect it to persist
* at the place it is now. Developers are free to move it anywhere
* anytime at will.
* @note To ruby-core: remember that this header can be possibly
* recursively included from extension libraries written in C++.
* Do not expect for instance `__VA_ARGS__` is always available.
* We assume C99 for ruby itself but we don't assume languages of
* extension libraries. They could be written in C++98.
* @brief Public APIs to provide ::rb_fd_select().
#include "ruby/internal/config.h"
#include "ruby/internal/attr/pure.h"
#include "ruby/internal/attr/const.h"

typedef struct {
int n;
int *fd; // TODO: a Vector-like sturct for dynamic allocation
} rb_fdset_t;

typedef fd_set rb_fdset_t;

# include <sys/epoll.h> /* for epoll(7) (Linux) */

int epoll_fd = -1;

#define rb_fd_zero rb_fd_zero
#define rb_fd_set rb_fd_set
#define rb_fd_clr rb_fd_clr
#define rb_fd_isset rb_fd_isset
#define rb_fd_init rb_fd_init
#define rb_fd_copy rb_fd_copy
#define rb_fd_dup rb_fd_dup
#define rb_fd_ptr rb_fd_ptr
#define rb_epoll_max_events 8
/** @endcond */

static inline void
rb_fd_zero(rb_fdset_t *dst)
dst->n = 0;
dst->fd = NULL;

static inline void
rb_fd_set(int fd, rb_fdset_t *dst)
int *new_fd;
new_fd = (int*) malloc(n * sizeof(int));
memcpy(new_fd, dst->fd, (n - 1) * sizeof(int));
new_fd[n-1] = fd;

static inline void
rb_fd_copy(rb_fdset_t *dst, const fd_set *src, int n)
*dst = *src;

static inline void
rb_fd_dup(rb_fdset_t *dst, const fd_set *src, int n)
*dst = *src;

/* :TODO: can this function be __attribute__((returns_nonnull)) or not? */
static inline fd_set *
rb_fd_ptr(rb_fdset_t *f)
return f;

static inline int
rb_fd_max(const rb_fdset_t *f)
return f->maxfd;

static inline void
if (epoll_fd == -1) {
epoll_fd = epoll_create1(0);
assert(epoll_id != -1);

static int
rb_fd_select(int n, rb_fdset_t *rfds, rb_fdset_t *wfds, rb_fdset_t *efds, struct timeval *timeout)
int epoll_timeout;
rb_epoll_init(); // lazily create epoll FD, since not everybody waits on I/O
epoll_timeout = (int) timeout->tv_sec * 1000 + timeout->tv_usec;
if (epoll_timeout < 0) epoll_timeout = INT_MAX; // Integer Overflow

// TODO: implement the conversion of epoll_events
// int epoll_wait(int epfd, struct epoll_event *events, int maxevents, int timeout);
epoll_wait(epoll_fd, x, rb_epoll_max_events, epoll_timeout);

/* :FIXME: What are these? They don't exist for shibling implementations. */
#define rb_fd_init_copy(d, s) (*(d) = *(s))
#define rb_fd_term(f) ((void)(f))