libev4.15学习

libev作为优秀的高性能IO框架，非常值得学习！

虽然我是菜鸟，但也必须学习啦，从今天一点一点地学习，慢慢进步！

# include "ev.h"

struct event_base;

//定义事件类型码，注意啦，都是2的指数幂
#define EVLIST_TIMEOUT  0x01
#define EVLIST_INSERTED 0x02
#define EVLIST_SIGNAL   0x04
#define EVLIST_ACTIVE   0x08
#define EVLIST_INTERNAL 0x10
#define EVLIST_INIT     0x80

//定义回调函数
typedef void (*event_callback_fn)(int, short, void *);

struct event
{
  /* libev watchers we map onto */
　//注意，这里union表示某一时间会有一个东东，比如在win32里就只有ev_io

  union {
    struct ev_io io;
    struct ev_signal sig;
  } iosig;
  struct ev_timer to;

  /* compatibility slots */
  struct event_base *ev_base;
  event_callback_fn ev_callback;
  void *ev_arg;
  int ev_fd;
  int ev_pri;
  int ev_res;
  int ev_flags;
  short ev_events;
};

event_callback_fn event_get_callback (const struct event *ev);

#define EV_READ                    EV_READ
#define EV_WRITE                   EV_WRITE
#define EV_PERSIST                 0x10
#define EV_ET                      0x20 /* nop */

//这里定义了一系列函数，其实封装成函数 感觉更好点

#define EVENT_SIGNAL(ev)           ((int) (ev)->ev_fd)
#define EVENT_FD(ev)               ((int) (ev)->ev_fd)

#define event_initialized(ev)      ((ev)->ev_flags & EVLIST_INIT)

#define evtimer_add(ev,tv)         event_add (ev, tv)
#define evtimer_set(ev,cb,data)    event_set (ev, -1, 0, cb, data)
#define evtimer_del(ev)            event_del (ev)
#define evtimer_pending(ev,tv)     event_pending (ev, EV_TIMEOUT, tv)
#define evtimer_initialized(ev)    event_initialized (ev)

#define timeout_add(ev,tv)         evtimer_add (ev, tv)
#define timeout_set(ev,cb,data)    evtimer_set (ev, cb, data)
#define timeout_del(ev)            evtimer_del (ev)
#define timeout_pending(ev,tv)     evtimer_pending (ev, tv)
#define timeout_initialized(ev)    evtimer_initialized (ev)

#define signal_add(ev,tv)          event_add (ev, tv)
#define signal_set(ev,sig,cb,data) event_set (ev, sig, EV_SIGNAL | EV_PERSIST, cb, data)
#define signal_del(ev)             event_del (ev)
#define signal_pending(ev,tv)      event_pending (ev, EV_SIGNAL, tv)
#define signal_initialized(ev)     event_initialized (ev)

const char *event_get_version (void);
const char *event_get_method (void);

void *event_init (void);
void event_base_free (struct event_base *base);

#define EVLOOP_ONCE      EVLOOP_ONESHOT
int event_loop (int);
int event_loopexit (struct timeval *tv);
int event_dispatch (void);

#define _EVENT_LOG_DEBUG 0
#define _EVENT_LOG_MSG   1
#define _EVENT_LOG_WARN  2
#define _EVENT_LOG_ERR   3
typedef void (*event_log_cb)(int severity, const char *msg);
void event_set_log_callback(event_log_cb cb);

void event_set (struct event *ev, int fd, short events, void (*cb)(int, short, void *), void *arg);
int event_once (int fd, short events, void (*cb)(int, short, void *), void *arg, struct timeval *tv);

int event_add (struct event *ev, struct timeval *tv);
int event_del (struct event *ev);
void event_active (struct event *ev, int res, short ncalls); /* ncalls is being ignored */

int event_pending (struct event *ev, short, struct timeval *tv);

int event_priority_init (int npri);
int event_priority_set (struct event *ev, int pri);

struct event_base *event_base_new (void);
const char *event_base_get_method (const struct event_base *);
int event_base_set (struct event_base *base, struct event *ev);
int event_base_loop (struct event_base *base, int);
int event_base_loopexit (struct event_base *base, struct timeval *tv);
int event_base_dispatch (struct event_base *base);
int event_base_once (struct event_base *base, int fd, short events, void (*cb)(int, short, void *), void *arg, struct timeval *tv);
int event_base_priority_init (struct event_base *base, int fd);

/* next line is different in the libevent+libev version */
/*libevent-include*/

#ifdef __cplusplus
}
#endif

#endif

上面是声明，下面可以看定义啦！

#include <stddef.h>
#include <stdlib.h>
#include <assert.h>
# include "event.h"


#if EV_MULTIPLICITY
# define dLOOPev struct ev_loop *loop = (struct ev_loop *)ev->ev_base
# define dLOOPbase struct ev_loop *loop = (struct ev_loop *)base
#else
# define dLOOPev
# define dLOOPbase
#endif

/* never accessed, will always be cast from/to ev_loop */
struct event_base
{
  int dummy;
};

static struct event_base *ev_x_cur;

//取得剩下的秒数
static ev_tstamp ev_tv_get (struct timeval *tv)
{
  if (tv)
    {
      ev_tstamp after = tv->tv_sec + tv->tv_usec * 1e-6;
      return after ? after : 1e-6;
    }
  else
    return -1.;
}

#define EVENT_STRINGIFY(s) # s
#define EVENT_VERSION(a,b) EVENT_STRINGIFY (a) "." EVENT_STRINGIFY (b)

const char *
event_get_version (void)
{
  /* returns ABI, not API or library, version */
  return EVENT_VERSION (EV_VERSION_MAJOR, EV_VERSION_MINOR);
}

const char *
event_get_method (void)
{
  return "libev";
}

void *event_init (void)
{
#if EV_MULTIPLICITY
  if (ev_x_cur)
    ev_x_cur = (struct event_base *)ev_loop_new (EVFLAG_AUTO);
  else
    ev_x_cur = (struct event_base *)ev_default_loop (EVFLAG_AUTO);
#else
  assert (("libev: multiple event bases not supported when not compiled with EV_MULTIPLICITY", !ev_x_cur));

  ev_x_cur = (struct event_base *)(long)ev_default_loop (EVFLAG_AUTO);
#endif

  return ev_x_cur;
}

const char *
event_base_get_method (const struct event_base *base)
{
  return "libev";
}

struct event_base *
event_base_new (void)
{
#if EV_MULTIPLICITY
  return (struct event_base *)ev_loop_new (EVFLAG_AUTO);
#else
  assert (("libev: multiple event bases not supported when not compiled with EV_MULTIPLICITY"));
  return NULL;
#endif
}

void event_base_free (struct event_base *base)
{
  dLOOPbase;

#if EV_MULTIPLICITY
  if (!ev_is_default_loop (loop))
    ev_loop_destroy (loop);
#endif
}

int event_dispatch (void)
{
  return event_base_dispatch (ev_x_cur);
}

#ifdef EV_STANDALONE
void event_set_log_callback (event_log_cb cb)
{
  /* nop */
}
#endif

int event_loop (int flags)
{
  return event_base_loop (ev_x_cur, flags);
}

int event_loopexit (struct timeval *tv)
{
  return event_base_loopexit (ev_x_cur, tv);
}

event_callback_fn event_get_callback
(const struct event *ev)
{
  return ev->ev_callback;
}

static void
ev_x_cb (struct event *ev, int revents)
{
  revents &= EV_READ | EV_WRITE | EV_TIMER | EV_SIGNAL;

  ev->ev_res = revents;
  ev->ev_callback (ev->ev_fd, (short)revents, ev->ev_arg);
}

static void
ev_x_cb_sig (EV_P_ struct ev_signal *w, int revents)
{
  struct event *ev = (struct event *)(((char *)w) - offsetof (struct event, iosig.sig));

  if (revents & EV_ERROR)
    event_del (ev);

  ev_x_cb (ev, revents);
}

static void
ev_x_cb_io (EV_P_ struct ev_io *w, int revents)
{
  struct event *ev = (struct event *)(((char *)w) - offsetof (struct event, iosig.io));

  if ((revents & EV_ERROR) || !(ev->ev_events & EV_PERSIST))
    event_del (ev);

  ev_x_cb (ev, revents);
}

static void
ev_x_cb_to (EV_P_ struct ev_timer *w, int revents)
{
  struct event *ev = (struct event *)(((char *)w) - offsetof (struct event, to));

  event_del (ev);

  ev_x_cb (ev, revents);
}

void event_set (struct event *ev, int fd, short events, void (*cb)(int, short, void *), void *arg)
{
  if (events & EV_SIGNAL)
    ev_init (&ev->iosig.sig, ev_x_cb_sig);
  else
    ev_init (&ev->iosig.io, ev_x_cb_io);

  ev_init (&ev->to, ev_x_cb_to);

  ev->ev_base     = ev_x_cur; /* not threadsafe, but it's how libevent works */
  ev->ev_fd       = fd;
  ev->ev_events   = events;
  ev->ev_pri      = 0;
  ev->ev_callback = cb;
  ev->ev_arg      = arg;
  ev->ev_res      = 0;
  ev->ev_flags    = EVLIST_INIT;
}

int event_once (int fd, short events, void (*cb)(int, short, void *), void *arg, struct timeval *tv)
{
  return event_base_once (ev_x_cur, fd, events, cb, arg, tv);
}

int event_add (struct event *ev, struct timeval *tv)
{
  dLOOPev;

  if (ev->ev_events & EV_SIGNAL)
    {
      if (!ev_is_active (&ev->iosig.sig))
        {
          ev_signal_set (&ev->iosig.sig, ev->ev_fd);
          ev_signal_start (EV_A_ &ev->iosig.sig);

          ev->ev_flags |= EVLIST_SIGNAL;
        }
    }
  else if (ev->ev_events & (EV_READ | EV_WRITE))
    {
      if (!ev_is_active (&ev->iosig.io))
        {
          ev_io_set (&ev->iosig.io, ev->ev_fd, ev->ev_events & (EV_READ | EV_WRITE));
          ev_io_start (EV_A_ &ev->iosig.io);

          ev->ev_flags |= EVLIST_INSERTED;
        }
    }

  if (tv)
    {
      ev->to.repeat = ev_tv_get (tv);
      ev_timer_again (EV_A_ &ev->to);
      ev->ev_flags |= EVLIST_TIMEOUT;
    }
  else
    {
      ev_timer_stop (EV_A_ &ev->to);
      ev->ev_flags &= ~EVLIST_TIMEOUT;
    }

  ev->ev_flags |= EVLIST_ACTIVE;

  return 0;
}

int event_del (struct event *ev)
{
  dLOOPev;

  if (ev->ev_events & EV_SIGNAL)
    ev_signal_stop (EV_A_ &ev->iosig.sig);
  else if (ev->ev_events & (EV_READ | EV_WRITE))
    ev_io_stop (EV_A_ &ev->iosig.io);

  if (ev_is_active (&ev->to))
    ev_timer_stop (EV_A_ &ev->to);

  ev->ev_flags = EVLIST_INIT;

  return 0;
}

void event_active (struct event *ev, int res, short ncalls)
{
  dLOOPev;

  if (res & EV_TIMEOUT)
    ev_feed_event (EV_A_ &ev->to, res & EV_TIMEOUT);

  if (res & EV_SIGNAL)
    ev_feed_event (EV_A_ &ev->iosig.sig, res & EV_SIGNAL);

  if (res & (EV_READ | EV_WRITE))
    ev_feed_event (EV_A_ &ev->iosig.io, res & (EV_READ | EV_WRITE));
}

int event_pending (struct event *ev, short events, struct timeval *tv)
{
  short revents = 0;
  dLOOPev;

  if (ev->ev_events & EV_SIGNAL)
    {
      /* sig */
      if (ev_is_active (&ev->iosig.sig) || ev_is_pending (&ev->iosig.sig))
        revents |= EV_SIGNAL;
    }
  else if (ev->ev_events & (EV_READ | EV_WRITE))
    {
      /* io */
      if (ev_is_active (&ev->iosig.io) || ev_is_pending (&ev->iosig.io))
        revents |= ev->ev_events & (EV_READ | EV_WRITE);
    }

  if (ev->ev_events & EV_TIMEOUT || ev_is_active (&ev->to) || ev_is_pending (&ev->to))
    {
      revents |= EV_TIMEOUT;

      if (tv)
        {
          ev_tstamp at = ev_now (EV_A);

          tv->tv_sec  = (long)at;
          tv->tv_usec = (long)((at - (ev_tstamp)tv->tv_sec) * 1e6);
        }
    }

  return events & revents;
}

int event_priority_init (int npri)
{
  return event_base_priority_init (ev_x_cur, npri);
}

int event_priority_set (struct event *ev, int pri)
{
  ev->ev_pri = pri;

  return 0;
}

int event_base_set (struct event_base *base, struct event *ev)
{
  ev->ev_base = base;

  return 0;
}

int event_base_loop (struct event_base *base, int flags)
{
  dLOOPbase;

  return !ev_run (EV_A_ flags);
}

int event_base_dispatch (struct event_base *base)
{
  return event_base_loop (base, 0);
}

static void
ev_x_loopexit_cb (int revents, void *base)
{
  dLOOPbase;

  ev_break (EV_A_ EVBREAK_ONE);
}

int event_base_loopexit (struct event_base *base, struct timeval *tv)
{
  ev_tstamp after = ev_tv_get (tv);
  dLOOPbase;

  ev_once (EV_A_ -1, 0, after >= 0. ? after : 0., ev_x_loopexit_cb, (void *)base);

  return 0;
}

struct ev_x_once
{
  int fd;
  void (*cb)(int, short, void *);
  void *arg;
};

static void
ev_x_once_cb (int revents, void *arg)
{
  struct ev_x_once *once = (struct ev_x_once *)arg;

  once->cb (once->fd, (short)revents, once->arg);
  free (once);
}

int event_base_once (struct event_base *base, int fd, short events, void (*cb)(int, short, void *), void *arg, struct timeval *tv)
{
  struct ev_x_once *once = (struct ev_x_once *)malloc (sizeof (struct ev_x_once));
  dLOOPbase;

  if (!once)
    return -1;

  once->fd  = fd;
  once->cb  = cb;
  once->arg = arg;

  ev_once (EV_A_ fd, events & (EV_READ | EV_WRITE), ev_tv_get (tv), ev_x_once_cb, (void *)once);

  return 0;
}

int event_base_priority_init (struct event_base *base, int npri)
{
  /*dLOOPbase;*/

  return 0;
}