/*
 * Copyright (C) Igor Sysoev
 */


#ifndef _NGX_EVENT_H_INCLUDED_
#define _NGX_EVENT_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>


#define NGX_INVALID_INDEX  0xd0d0d0d0


#if (NGX_HAVE_IOCP)

typedef struct {
    WSAOVERLAPPED    ovlp;
    ngx_event_t     *event;
    int              error;
} ngx_event_ovlp_t;

#endif


typedef struct {
    ngx_uint_t       lock;

    ngx_event_t     *events;
    ngx_event_t     *last;
} ngx_event_mutex_t;


struct ngx_event_s {
    void            *data;

    unsigned         write:1;

    unsigned         accept:1;

    unsigned         oneshot:1;

    /* used to detect the stale events in kqueue, rt signals and epoll */
    unsigned         instance:1;

    /*
     * the event was passed or would be passed to a kernel;
     * in aio mode - operation was posted.
     */
    unsigned         active:1;

    unsigned         disabled:1;

    /* the ready event; in aio mode 0 means that no operation can be posted */
    unsigned         ready:1;

    /* aio operation is complete */
    unsigned         complete:1;

    unsigned         eof:1;
    unsigned         error:1;

    unsigned         timedout:1;
    unsigned         timer_set:1;

    unsigned         delayed:1;

    unsigned         read_discarded:1;

    unsigned         unexpected_eof:1;

    unsigned         deferred_accept:1;

    /* the pending eof reported by kqueue or in aio chain operation */
    unsigned         pending_eof:1;

#if !(NGX_THREADS)
    unsigned         posted_ready:1;
#endif

#if (NGX_WIN32)
    /* setsockopt(SO_UPDATE_ACCEPT_CONTEXT) was succesfull */
    unsigned         accept_context_updated:1;
#endif

#if (NGX_HAVE_KQUEUE)
    unsigned         kq_vnode:1;

    /* the pending errno reported by kqueue */
    int              kq_errno;
#endif

    /*
     * kqueue only:
     *   accept:     number of sockets that wait to be accepted
     *   read:       bytes to read when event is ready
     *               or lowat when event is set with NGX_LOWAT_EVENT flag
     *   write:      available space in buffer when event is ready
     *               or lowat when event is set with NGX_LOWAT_EVENT flag
     *
     * iocp: TODO
     *
     * otherwise:
     *   accept:     1 if accept many, 0 otherwise
     */

#if (NGX_HAVE_KQUEUE) || (NGX_HAVE_IOCP)
    int              available;
#else
    unsigned         available:1;
#endif

    /* TODO rename to handler */
    ngx_event_handler_pt  event_handler;


#if (NGX_HAVE_AIO)

#if (NGX_HAVE_IOCP)
    ngx_event_ovlp_t ovlp;
#else
    struct aiocb     aiocb;
#endif

#endif

    u_int            index;

    ngx_log_t       *log;

    /* TODO: threads: padding to cache line */

    /*
     * STUB: The inline of "ngx_rbtree_t  rbtree;"
     */

    ngx_int_t        rbtree_key;
    void            *rbtree_left;
    void            *rbtree_right;
    void            *rbtree_parent;
    char             rbtree_color;


    unsigned         closed:1;

#if (NGX_THREADS)

    unsigned         locked:1;

    unsigned         posted_ready:1;
    unsigned         posted_timedout:1;
    unsigned         posted_eof:1;

#if (NGX_HAVE_KQUEUE)
    /* the pending errno reported by kqueue */
    int              posted_errno;
#endif

#if (NGX_HAVE_KQUEUE) || (NGX_HAVE_IOCP)
    int              posted_available;
#else
    unsigned         posted_available:1;
#endif

    ngx_atomic_t    *lock;
    ngx_atomic_t    *own_lock;

#endif

    /* the links of the posted queue */
    ngx_event_t     *next;
    ngx_event_t    **prev;


#if 0

    /* the threads support */

    /*
     * the event thread context, we store it here
     * if $(CC) does not understand __thread declaration
     * and pthread_getspecific() is too costly
     */

    void            *thr_ctx;

#if (NGX_EVENT_T_PADDING)

    /* event should not cross cache line in SMP */

    int              padding[NGX_EVENT_T_PADDING];
#endif
#endif
};


typedef struct {
    ngx_int_t  (*add)(ngx_event_t *ev, int event, u_int flags);
    ngx_int_t  (*del)(ngx_event_t *ev, int event, u_int flags);

    ngx_int_t  (*enable)(ngx_event_t *ev, int event, u_int flags);
    ngx_int_t  (*disable)(ngx_event_t *ev, int event, u_int flags);

    ngx_int_t  (*add_conn)(ngx_connection_t *c);
    ngx_int_t  (*del_conn)(ngx_connection_t *c, u_int flags);

    ngx_int_t  (*process_changes)(ngx_cycle_t *cycle, ngx_uint_t nowait);
    ngx_int_t  (*process_events)(ngx_cycle_t *cycle);

    ngx_int_t  (*init)(ngx_cycle_t *cycle);
    void       (*done)(ngx_cycle_t *cycle);
} ngx_event_actions_t;


extern ngx_event_actions_t   ngx_event_actions;


/*
 * The event filter requires to read/write the whole data -
 * select, poll, /dev/poll, kqueue, epoll.
 */
#define NGX_USE_LEVEL_EVENT      0x00000001

/*
 * The event filter is deleted after a notification without an additional
 * syscall - select, poll, kqueue, epoll, Solaris 10's event ports.
 */
#define NGX_USE_ONESHOT_EVENT    0x00000002

/*
 * The event filter notifies only the changes and an initial level -
 * kqueue, epoll.
 */
#define NGX_USE_CLEAR_EVENT      0x00000004

/*
 * The event filter has kqueue features - the eof flag, errno,
 * available data, etc.
 */
#define NGX_USE_KQUEUE_EVENT    0x00000008

/*
 * The event filter supports low water mark - kqueue's NOTE_LOWAT.
 * kqueue in FreeBSD 4.1-4.2 has no NOTE_LOWAT so we need a separate flag.
 */
#define NGX_USE_LOWAT_EVENT     0x00000010

/*
 * The event filter requires to do i/o operation until EAGAIN -
 * epoll, rt signals.
 */
#define NGX_USE_GREEDY_EVENT    0x00000020

/*
 * The event filter is epoll,
 */
#define NGX_USE_EPOLL_EVENT      0x00000040

/*
 * No need to add or delete the event filters - rt signals.
 */
#define NGX_USE_RTSIG_EVENT      0x00000080

/*
 * No need to add or delete the event filters - overlapped, aio_read,
 * aioread, io_submit.
 */
#define NGX_USE_AIO_EVENT        0x00000100

/*
 * Need to add socket or handle only once - i/o completion port.
 * It also requires NGX_HAVE_AIO and NGX_USE_AIO_EVENT to be set.
 */
#define NGX_USE_IOCP_EVENT       0x00000200



/*
 * The event filter is deleted before the closing file.
 * Has no meaning for select, poll, epoll.
 *
 * kqueue:     kqueue deletes event filters for file that closed
 *             so we need only to delete filters in user-level batch array
 * /dev/poll:  we need to flush POLLREMOVE event before closing file
 */

#define NGX_CLOSE_EVENT    1
#define NGX_DISABLE_EVENT  2


/* these flags have a meaning only for kqueue */
#define NGX_LOWAT_EVENT    0
#define NGX_VNODE_EVENT    0


#if (NGX_HAVE_KQUEUE)

#define NGX_READ_EVENT     EVFILT_READ
#define NGX_WRITE_EVENT    EVFILT_WRITE

#undef  NGX_VNODE_EVENT
#define NGX_VNODE_EVENT    EVFILT_VNODE

/*
 * NGX_CLOSE_EVENT and NGX_LOWAT_EVENT are the module flags and they would
 * not go into a kernel so we need to choose the value that would not interfere
 * with any existent and future kqueue flags.  kqueue has such values -
 * EV_FLAG1, EV_EOF and EV_ERROR.  They are reserved and cleared on a kernel
 * entrance.
 */
#undef  NGX_CLOSE_EVENT
#define NGX_CLOSE_EVENT    EV_EOF

#undef  NGX_LOWAT_EVENT
#define NGX_LOWAT_EVENT    EV_FLAG1

#define NGX_LEVEL_EVENT    0
#define NGX_ONESHOT_EVENT  EV_ONESHOT
#define NGX_CLEAR_EVENT    EV_CLEAR

#undef  NGX_DISABLE_EVENT
#define NGX_DISABLE_EVENT  EV_DISABLE


#elif (NGX_HAVE_DEVPOLL)

#define NGX_READ_EVENT     POLLIN
#define NGX_WRITE_EVENT    POLLOUT

#define NGX_LEVEL_EVENT    0
#define NGX_ONESHOT_EVENT  1


#elif (NGX_HAVE_EPOLL)

#define NGX_READ_EVENT     EPOLLIN
#define NGX_WRITE_EVENT    EPOLLOUT

#define NGX_LEVEL_EVENT    0
#define NGX_CLEAR_EVENT    EPOLLET
#define NGX_ONESHOT_EVENT  0x70000000
#if 0
#define NGX_ONESHOT_EVENT  EPOLLONESHOT
#endif


#elif (NGX_HAVE_POLL)

#define NGX_READ_EVENT     POLLIN
#define NGX_WRITE_EVENT    POLLOUT

#define NGX_LEVEL_EVENT    0
#define NGX_ONESHOT_EVENT  1


#else /* select */

#define NGX_READ_EVENT     0
#define NGX_WRITE_EVENT    1

#define NGX_LEVEL_EVENT    0
#define NGX_ONESHOT_EVENT  1

#endif /* NGX_HAVE_KQUEUE */


#if (NGX_HAVE_IOCP)
#define NGX_IOCP_ACCEPT      0
#define NGX_IOCP_IO          1
#define NGX_IOCP_CONNECT     2
#endif


#ifndef NGX_CLEAR_EVENT
#define NGX_CLEAR_EVENT    0    /* dummy declaration */
#endif


#define ngx_process_changes  ngx_event_actions.process_changes
#define ngx_process_events   ngx_event_actions.process_events
#define ngx_done_events      ngx_event_actions.done

#define ngx_add_event        ngx_event_actions.add
#define ngx_del_event        ngx_event_actions.del
#define ngx_add_conn         ngx_event_actions.add_conn
#define ngx_del_conn         ngx_event_actions.del_conn

#define ngx_add_timer        ngx_event_add_timer
#define ngx_del_timer        ngx_event_del_timer


#define ngx_recv             ngx_io.recv
#define ngx_recv_chain       ngx_io.recv_chain
#define ngx_send             ngx_io.send
#define ngx_send_chain       ngx_io.send_chain



#define NGX_EVENT_MODULE      0x544E5645  /* "EVNT" */
#define NGX_EVENT_CONF        0x02000000


typedef struct {
    ngx_uint_t    connections;
    ngx_uint_t    use;

    ngx_flag_t    multi_accept;
    ngx_flag_t    accept_mutex;

    ngx_msec_t    accept_mutex_delay;

    u_char       *name;

#if (NGX_DEBUG)
    ngx_array_t   debug_connection;
#endif
} ngx_event_conf_t;


typedef struct {
    ngx_str_t              *name;

    void                 *(*create_conf)(ngx_cycle_t *cycle);
    char                 *(*init_conf)(ngx_cycle_t *cycle, void *conf);

    ngx_event_actions_t     actions;
} ngx_event_module_t;


extern ngx_atomic_t          *ngx_connection_counter;

extern ngx_atomic_t          *ngx_accept_mutex_ptr;
extern ngx_atomic_t          *ngx_accept_mutex;
extern ngx_uint_t             ngx_accept_mutex_held;
extern ngx_msec_t             ngx_accept_mutex_delay;
extern ngx_int_t              ngx_accept_disabled;


#if (NGX_STAT_STUB)

extern ngx_atomic_t  *ngx_stat_accepted;
extern ngx_atomic_t  *ngx_stat_requests;
extern ngx_atomic_t  *ngx_stat_active;
extern ngx_atomic_t  *ngx_stat_reading;
extern ngx_atomic_t  *ngx_stat_writing;

#endif



#define ngx_accept_mutex_unlock()                                             \
           if (ngx_accept_mutex_held) {                                       \
               *ngx_accept_mutex = 0;                                         \
           }


extern ngx_uint_t             ngx_event_flags;
extern ngx_module_t           ngx_events_module;
extern ngx_module_t           ngx_event_core_module;


#define ngx_event_get_conf(conf_ctx, module)                                  \
             (*(ngx_get_conf(conf_ctx, ngx_events_module))) [module.ctx_index];



void ngx_event_accept(ngx_event_t *ev);
ngx_int_t ngx_trylock_accept_mutex(ngx_cycle_t *cycle);
ngx_int_t ngx_disable_accept_events(ngx_cycle_t *cycle);
ngx_int_t ngx_enable_accept_events(ngx_cycle_t *cycle);


#if (NGX_WIN32)
void ngx_event_acceptex(ngx_event_t *ev);
int ngx_event_post_acceptex(ngx_listening_t *ls, int n);
#endif


ngx_int_t ngx_send_lowat(ngx_connection_t *c, size_t lowat);


/* used in ngx_log_debugX() */
#define ngx_event_ident(p)  ((ngx_connection_t *) (p))->fd


#include <ngx_event_timer.h>
#include <ngx_event_posted.h>
#include <ngx_event_busy_lock.h>

#if (NGX_WIN32)
#include <ngx_iocp_module.h>
#endif



static ngx_inline ngx_int_t ngx_handle_read_event(ngx_event_t *rev, u_int flags)
{
    if (ngx_event_flags & NGX_USE_CLEAR_EVENT) {

        /* kqueue, epoll */

        if (!rev->active && !rev->ready) {
            if (ngx_add_event(rev, NGX_READ_EVENT, NGX_CLEAR_EVENT)
                                                                == NGX_ERROR) {
                return NGX_ERROR;
            }
        }

        return NGX_OK;

    } else if (ngx_event_flags & NGX_USE_LEVEL_EVENT) {

        /* select, poll, /dev/poll */

        if (!rev->active && !rev->ready) {
            if (ngx_add_event(rev, NGX_READ_EVENT, NGX_LEVEL_EVENT)
                                                                  == NGX_ERROR)
            {
                return NGX_ERROR;
            }

            return NGX_OK;
        }

        if (rev->active && (rev->ready || (flags & NGX_CLOSE_EVENT))) {
            if (ngx_del_event(rev, NGX_READ_EVENT, flags) == NGX_ERROR) {
                return NGX_ERROR;
            }

            return NGX_OK;
        }
    }

    /* aio, iocp, rtsig */

    return NGX_OK;
}


static ngx_inline ngx_int_t ngx_handle_level_read_event(ngx_event_t *rev)
{
    if (ngx_event_flags & NGX_USE_LEVEL_EVENT) {
        if (!rev->active && !rev->ready) {
            if (ngx_add_event(rev, NGX_READ_EVENT, NGX_LEVEL_EVENT)
                                                                  == NGX_ERROR)
            {
                return NGX_ERROR;
            }

            return NGX_OK;
        }

        if (rev->active && rev->ready) {
            if (ngx_del_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
                return NGX_ERROR;
            }

            return NGX_OK;
        }
    }

    return NGX_OK;
}


static ngx_inline ngx_int_t ngx_handle_write_event(ngx_event_t *wev,
                                                   size_t lowat)
{
    ngx_connection_t  *c;

    if (lowat) {
        c = (ngx_connection_t *) wev->data;

        if (ngx_send_lowat(c, lowat) == NGX_ERROR) {
            return NGX_ERROR;
        }
    }

    if (ngx_event_flags & NGX_USE_CLEAR_EVENT) {

        /* kqueue, epoll */

        if (!wev->active && !wev->ready) {
            if (ngx_add_event(wev, NGX_WRITE_EVENT,
                              NGX_CLEAR_EVENT | (lowat ? NGX_LOWAT_EVENT : 0))
                                                                  == NGX_ERROR)
            {
                return NGX_ERROR;
            }
        }

        return NGX_OK;

    } else if (ngx_event_flags & NGX_USE_LEVEL_EVENT) {

        /* select, poll, /dev/poll */

        if (!wev->active && !wev->ready) {
            if (ngx_add_event(wev, NGX_WRITE_EVENT, NGX_LEVEL_EVENT)
                                                                  == NGX_ERROR)
            {
                return NGX_ERROR;
            }

            return NGX_OK;
        }

        if (wev->active && wev->ready) {
            if (ngx_del_event(wev, NGX_WRITE_EVENT, 0) == NGX_ERROR) {
                return NGX_ERROR;
            }

            return NGX_OK;
        }
    }

    /* aio, iocp, rtsig */

    return NGX_OK;
}


static ngx_inline ngx_int_t ngx_handle_level_write_event(ngx_event_t *wev)
{
    if (ngx_event_flags & NGX_USE_LEVEL_EVENT) {
        if (!wev->active && !wev->ready) {
            if (ngx_add_event(wev, NGX_WRITE_EVENT, NGX_LEVEL_EVENT)
                                                                  == NGX_ERROR)
            {
                return NGX_ERROR;
            }

            return NGX_OK;
        }

        if (wev->active && wev->ready) {
            if (ngx_del_event(wev, NGX_WRITE_EVENT, 0) == NGX_ERROR) {
                return NGX_ERROR;
            }

            return NGX_OK;
        }
    }

    return NGX_OK;
}


#endif /* _NGX_EVENT_H_INCLUDED_ */