event模塊底層各種事件機制

1.aio機制

nginx_aio_module.c

static ngx_str_t      aio_name = ngx_string("aio");

ngx_event_module_t  ngx_aio_module_ctx = {
    &aio_name,
    NULL,                                  /* create configuration */
    NULL,                                  /* init configuration */

    {
        ngx_aio_add_event,                 /* add an event */
        ngx_aio_del_event,                 /* delete an event */
        NULL,                              /* enable an event */
        NULL,                              /* disable an event */
        NULL,                              /* add an connection */
        ngx_aio_del_connection,            /* delete an connection */
        NULL,                              /* process the changes */
        ngx_aio_process_events,            /* process the events */
        ngx_aio_init,                      /* init the events */
        ngx_aio_done                       /* done the events */
    }

};

ngx_module_t  ngx_aio_module = {
    NGX_MODULE_V1,
    &ngx_aio_module_ctx,                   /* module context */
    NULL,                                  /* module directives */
    NGX_EVENT_MODULE,                      /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};

兩個數據結構：模塊ngx_aio_module和模塊上下文ngx_aio_module_ctx

2.devpoll機制

static struct pollfd   *change_list, *event_list;
static ngx_uint_t       nchanges, max_changes, nevents;

static ngx_event_t    **change_index;


static ngx_str_t      devpoll_name = ngx_string("/dev/poll");

static ngx_command_t  ngx_devpoll_commands[] = {

    { ngx_string("devpoll_changes"),
      NGX_EVENT_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_num_slot,
      0,
      offsetof(ngx_devpoll_conf_t, changes),
      NULL },

    { ngx_string("devpoll_events"),
      NGX_EVENT_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_num_slot,
      0,
      offsetof(ngx_devpoll_conf_t, events),
      NULL },

      ngx_null_command
};


ngx_event_module_t  ngx_devpoll_module_ctx = {
    &devpoll_name,
    ngx_devpoll_create_conf,               /* create configuration */
    ngx_devpoll_init_conf,                 /* init configuration */

    {
        ngx_devpoll_add_event,             /* add an event */
        ngx_devpoll_del_event,             /* delete an event */
        ngx_devpoll_add_event,             /* enable an event */
        ngx_devpoll_del_event,             /* disable an event */
        NULL,                              /* add an connection */
        NULL,                              /* delete an connection */
        NULL,                              /* process the changes */
        ngx_devpoll_process_events,        /* process the events */
        ngx_devpoll_init,                  /* init the events */
        ngx_devpoll_done,                  /* done the events */
    }

};

ngx_module_t  ngx_devpoll_module = {
    NGX_MODULE_V1,
    &ngx_devpoll_module_ctx,               /* module context */
    ngx_devpoll_commands,                  /* module directives */
    NGX_EVENT_MODULE,                      /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};

三個數據結構，ngx_devpoll_commands讀取配置文件使用；

3.epoll機制

static ngx_str_t      epoll_name = ngx_string("epoll");

static ngx_command_t  ngx_epoll_commands[] = {

    { ngx_string("epoll_events"),
      NGX_EVENT_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_num_slot,
      0,
      offsetof(ngx_epoll_conf_t, events),
      NULL },

    { ngx_string("worker_aio_requests"),
      NGX_EVENT_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_num_slot,
      0,
      offsetof(ngx_epoll_conf_t, aio_requests),
      NULL },

      ngx_null_command
};


ngx_event_module_t  ngx_epoll_module_ctx = {
    &epoll_name,
    ngx_epoll_create_conf,               /* create configuration */
    ngx_epoll_init_conf,                 /* init configuration */

    {
        ngx_epoll_add_event,             /* add an event */
        ngx_epoll_del_event,             /* delete an event */
        ngx_epoll_add_event,             /* enable an event */
        ngx_epoll_del_event,             /* disable an event */
        ngx_epoll_add_connection,        /* add an connection */
        ngx_epoll_del_connection,        /* delete an connection */
        NULL,                            /* process the changes */
        ngx_epoll_process_events,        /* process the events */
        ngx_epoll_init,                  /* init the events */
        ngx_epoll_done,                  /* done the events */
    }
};

ngx_module_t  ngx_epoll_module = {
    NGX_MODULE_V1,
    &ngx_epoll_module_ctx,               /* module context */
    ngx_epoll_commands,                  /* module directives */
    NGX_EVENT_MODULE,                    /* module type */
    NULL,                                /* init master */
    NULL,                                /* init module */
    NULL,                                /* init process */
    NULL,                                /* init thread */
    NULL,                                /* exit thread */
    NULL,                                /* exit process */
    NULL,                                /* exit master */
    NGX_MODULE_V1_PADDING
};