new file mode 100644
--- /dev/null
+++ b/src/event/ngx_event.h
@@ -0,0 +1,637 @@
+
+/*
+ * 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 (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 (WIN32)
+    /* setsockopt(SO_UPDATE_ACCEPT_CONTEXT) was succesfull */
+    unsigned         accept_context_updated:1;
+#endif
+
+#if (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 (HAVE_KQUEUE) || (HAVE_IOCP)
+    int              available;
+#else
+    unsigned         available:1;
+#endif
+
+    /* TODO rename to handler */
+    ngx_event_handler_pt  event_handler;
+
+
+#if (HAVE_AIO)
+
+#if (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 (HAVE_KQUEUE)
+    /* the pending errno reported by kqueue */
+    int              posted_errno;
+#endif
+
+#if (HAVE_KQUEUE) || (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 try);
+    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_HAVE_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_HAVE_LOWAT_EVENT     0x00000010
+
+/*
+ * The event filter requires to do i/o operation until EAGAIN -
+ * epoll, rt signals.
+ */
+#define NGX_HAVE_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 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 (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 (HAVE_DEVPOLL)
+
+#define NGX_READ_EVENT     POLLIN
+#define NGX_WRITE_EVENT    POLLOUT
+
+#define NGX_LEVEL_EVENT    0
+#define NGX_ONESHOT_EVENT  1
+
+
+#elif (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 (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 /* HAVE_KQUEUE */
+
+
+#if (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 (WIN32)
+void ngx_event_acceptex(ngx_event_t *ev);
+int ngx_event_post_acceptex(ngx_listening_t *ls, int n);
+#endif
+
+
+/* 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 (WIN32)
+#include <ngx_iocp_module.h>
+#endif
+
+
+
+ngx_inline static int ngx_handle_read_event(ngx_event_t *rev, u_int flags)
+{
+    if (ngx_event_flags & NGX_USE_CLEAR_EVENT) {
+
+        /* kqueue */
+
+        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, epoll, rtsig */
+
+    return NGX_OK;
+}
+
+
+ngx_inline static int 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;
+}
+
+
+ngx_inline static int ngx_handle_write_event(ngx_event_t *wev, u_int flags)
+{
+    if (ngx_event_flags & NGX_USE_CLEAR_EVENT) {
+
+        /* kqueue */
+
+        if (!wev->active && !wev->ready) {
+            if (ngx_add_event(wev, NGX_WRITE_EVENT, NGX_CLEAR_EVENT|flags)
+                                                                  == 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, epoll, rtsig */
+
+    return NGX_OK;
+}
+
+
+ngx_inline static int 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_ */