event.h中的主要数据结构与宏定义

主要的宏定义：

//设定链表类型
#define EVLIST_TIMEOUT    0x01 //超时链表
#define EVLIST_INSERTED    0x02    //初始链表，若该event刚刚被加入eventbase中，则进入到EVLIST_INSERTED链表
#define EVLIST_SIGNAL    0x04    //信号链表
#define EVLIST_ACTIVE    0x08    //激活的event链表
#define EVLIST_INTERNAL    0x10    //内部链表
#define EVLIST_INIT    0x80    //

/* EVLIST_X_ Private space: 0x1000-0xf000 */
#define EVLIST_ALL    (0xf000 | 0x9f) //所有链表类型的或操作得到的

//event类型
#define EV_TIMEOUT    0x01 //超时
#define EV_READ        0x02 //读
#define EV_WRITE    0x04 //写
#define EV_SIGNAL    0x08 //信号
#define EV_PERSIST    0x10    /* Persistant event */

//日志级别
#define _EVENT_LOG_DEBUG 0  //DEBUG
#define _EVENT_LOG_MSG 1    //MSG
#define _EVENT_LOG_WARN 2    //WARN
#define _EVENT_LOG_ERR 3    //ERR

/**
 event_loop() flags
 */
/*@{*/
#define EVLOOP_ONCE    0x01    /**< Block at most once. */
#define EVLOOP_NONBLOCK    0x02    /**< Do not block. */

主要的数据结构：

struct event {
    TAILQ_ENTRY (event) ev_next; //该指针指向event_base中eventqueue链表的下一个元素
    TAILQ_ENTRY (event) ev_active_next;//该指针指向event_base中的activequeue[i]链表的下一个元素
    TAILQ_ENTRY (event) ev_signal_next;//该指针指向event_base中的sig结构中的evsigevents[i]链表的下一个元素
    unsigned int min_heap_idx;    /* for managing timeouts *///该结构标识该event在最小堆的序号

    struct event_base *ev_base; //指向event_base

    int ev_fd; //文件fd
    short ev_events; //事件类型，如EV_TIMEOUT，EV_READ，EV_WRITE等
    short ev_ncalls; //该事件的回调函数被执行的次数
    short *ev_pncalls;    /* Allows deletes in callback */ //指向ev_ncalls

    struct timeval ev_timeout; //该event的超时时间

    int ev_pri;        /* smaller numbers are higher priority *///该event的优先级

    void (*ev_callback)(int, short, void *arg); //该event被触发的回调函数
    void *ev_arg; //回调函数参数

    int ev_res;        /* result passed to event callback */
    int ev_flags; //标识该event是在哪个链表之中，可以是EVLIST_TIMEOUT，EVLIST_INSERTED，EVLIST_ACTIVE，EVLIST_INTERNAL的组合
}

evhttp的主要结构（待分析）

/*
 * Key-Value pairs. Can be used for HTTP headers but also for
 * query argument parsing.
 */
struct evkeyval {
    TAILQ_ENTRY(evkeyval) next;

    char *key;
    char *value;
}

evbuffer的主要结构（待分析）

struct evbuffer {
    u_char *buffer;
    u_char *orig_buffer;

    size_t misalign;
    size_t totallen;
    size_t off;

    void (*cb)(struct evbuffer *, size_t, size_t, void *);
    void *cbarg;
}

/* Just for error reporting - use other constants otherwise */
#define EVBUFFER_READ        0x01
#define EVBUFFER_WRITE        0x02
#define EVBUFFER_EOF        0x10
#define EVBUFFER_ERROR        0x20
#define EVBUFFER_TIMEOUT    0x40

struct bufferevent;
typedef void (*evbuffercb)(struct bufferevent *, void *);
typedef void (*everrorcb)(struct bufferevent *, short what, void *)

struct event_watermark {
    size_t low;
    size_t high;
}

struct bufferevent {
    struct event_base *ev_base;

    struct event ev_read;
    struct event ev_write;

    struct evbuffer *input;
    struct evbuffer *output;

    struct event_watermark wm_read;
    struct event_watermark wm_write;

    evbuffercb readcb;
    evbuffercb writecb;
    everrorcb errorcb;
    void *cbarg;

    int timeout_read;    /* in seconds */
    int timeout_write;    /* in seconds */

    short enabled;    /* events that are currently enabled */
}