上一篇讲完了initServer的大体流程，其中aeCreateEventLoop（）,这个函数没有详细说明，我们在这一篇里讲述Ae.h和Ae.c, 这里面的api阐述了如何创建
eventLoop和添加文件读写事件等等。
ae.h中的解释
//文件读写事件回调函数typedef void aeFileProc(struct aeEventLoop *eventLoop, int fd, void *clientData, int mask);
//定时器回调函数typedef int aeTimeProc(struct aeEventLoop *eventLoop, long long id, void *clientData);
//事件结束回调函数，析构一些资源typedef void aeEventFinalizerProc(struct aeEventLoop *eventLoop, void *clientData);
//不是很清楚，应该是进程结束前做的回调函数typedef void aeBeforeSleepProc(struct aeEventLoop *eventLoop);
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//文件事件回调函数typedef struct aeFileEvent {int mask; /* one of AE_(READABLE|WRITABLE) */ //文件事件类型 读/写aeFileProc *rfileProc;aeFileProc *wfileProc;void *clientData;} aeFileEvent;/* A fired event */typedef struct aeFiredEvent {int fd; ////已出现的事件的文件号对应的事件描述在aeEventLoop.events[]中的下标int mask; //文件事件类型 AE_WRITABLE||AE_READABLE} aeFiredEvent;typedef struct aeTimeEvent {long long id; /* time event identifier. */ //由aeEventLoop.timeEventNextId进行管理long when_sec; /* seconds */long when_ms; /* milliseconds */aeTimeProc *timeProc;aeEventFinalizerProc *finalizerProc;void *clientData;struct aeTimeEvent *next;} aeTimeEvent;/* State of an event based program */typedef struct aeEventLoop {int maxfd; //监听的最大文件号int setsize; //跟踪的文件描述符最大数量long long timeEventNextId; //定时器事件的ID编号管理（分配ID号所用）time_t lastTime; /* Used to detect system clock skew */aeFileEvent *events; //注册的文件事件，这些是需要进程关注的文件aeFiredEvent *fired; //poll结果，待处理的文件事件的文件号和事件类型aeTimeEvent *timeEventHead; //定时器时间链表int stop; //时间轮询是否结束？void *apidata; //polling API 特殊的数据aeBeforeSleepProc *beforesleep; //休眠前的程序} aeEventLoop;
/ Prototypes /
//创建eventLoop结构
aeEventLoop *aeCreateEventLoop(int setsize);
//删除eventloop
void aeDeleteEventLoop(aeEventLoop *eventLoop);
//事件派发停止
void aeStop(aeEventLoop *eventLoop);
//添加文件读写事件
int aeCreateFileEvent(aeEventLoop *eventLoop, int fd, int mask,
aeFileProc *proc, void *clientData);
//删除文件读写事件
void aeDeleteFileEvent(aeEventLoop *eventLoop, int fd, int mask);
//获取文件事件对应类型(读或写)
int aeGetFileEvents(aeEventLoop *eventLoop, int fd);
//创建定时器事件
long long aeCreateTimeEvent(aeEventLoop *eventLoop,
long long milliseconds,aeTimeProc *proc, void *clientData,
aeEventFinalizerProc *finalizerProc);
//删除定时器事件
int aeDeleteTimeEvent(aeEventLoop *eventLoop, long long id);
//派发事件
int aeProcessEvents(aeEventLoop *eventLoop, int flags);
//等待millionseconds直到文件描述符可读或者可写
int aeWait(int fd, int mask, long long milliseconds);
//ae事件轮询主函数
void aeMain(aeEventLoop *eventLoop);
//获取当前网络模型
char *aeGetApiName(void);
//进程休眠前回调函数
void aeSetBeforeSleepProc(aeEventLoop *eventLoop,
aeBeforeSleepProc *beforesleep);
//获取eventloop所有的事件个数
int aeGetSetSize(aeEventLoop *eventLoop);
//重新设置eventloop事件个数
int aeResizeSetSize(aeEventLoop *eventLoop, int setsize);
ae.cpp中，一个函数一个函数解析
//定义了几个宏，根据不同的宏加载//不同的网络模型#ifdef HAVE_EVPORT#include "ae_evport.c"#else#ifdef HAVE_EPOLL#include "ae_epoll.c"#else#ifdef HAVE_KQUEUE#include "ae_kqueue.c"#else#include "ae_select.c"#endif#endif#endif
aeCreateEventLoop,主要负责eventloop结构的创建和初始化，以及模型的初始化
aeEventLoop *aeCreateEventLoop(int setsize) {aeEventLoop *eventLoop;int i;//创建eventloopif ((eventLoop = zmalloc(sizeof(*eventLoop))) == NULL) goto err;//为进程要注册的文件开辟空间eventLoop->events = zmalloc(sizeof(aeFileEvent)*setsize);//为激活的要处理的文件开辟空间eventLoop->fired = zmalloc(sizeof(aeFiredEvent)*setsize);//开辟失败报错if (eventLoop->events == NULL || eventLoop->fired == NULL) goto err;//设置监听事件总数eventLoop->setsize = setsize;//更新为当前时间eventLoop->lastTime = time(NULL);eventLoop->timeEventHead = NULL;eventLoop->timeEventNextId = 0;eventLoop->stop = 0;eventLoop->maxfd = -1;eventLoop->beforesleep = NULL;//将不同模式的api注册到eventloop里if (aeApiCreate(eventLoop) == -1) goto err;/* Events with mask == AE_NONE are not set. So let's initialize the* vector with it. */for (i = 0; i < setsize; i++)//将所有文件事件类型初始为空eventLoop->events[i].mask = AE_NONE;return eventLoop;err:if (eventLoop) {zfree(eventLoop->events);zfree(eventLoop->fired);zfree(eventLoop);}return NULL;}
//事件队列大小和重置//获取eventloop事件队列大小int aeGetSetSize(aeEventLoop *eventLoop) {return eventLoop->setsize;}//重新设置大小int aeResizeSetSize(aeEventLoop *eventLoop, int setsize) {int i;if (setsize == eventLoop->setsize) return AE_OK;if (eventLoop->maxfd >= setsize) return AE_ERR;//不同的网络模型调用不同的resizeif (aeApiResize(eventLoop,setsize) == -1) return AE_ERR;//重新开辟空间eventLoop->events = zrealloc(eventLoop->events,sizeof(aeFileEvent)*setsize);eventLoop->fired = zrealloc(eventLoop->fired,sizeof(aeFiredEvent)*setsize);eventLoop->setsize = setsize;/* Make sure that if we created new slots, they are initialized with* an AE_NONE mask. *///重新初始化事件类型for (i = eventLoop->maxfd+1; i < setsize; i++)eventLoop->events[i].mask = AE_NONE;return AE_OK;}
删除eventloop和stop事件轮询
//删除eventloop结构void aeDeleteEventLoop(aeEventLoop *eventLoop) {aeApiFree(eventLoop);zfree(eventLoop->events);zfree(eventLoop->fired);zfree(eventLoop);}//设置eventloop停止标记void aeStop(aeEventLoop *eventLoop) {eventLoop->stop = 1;}
创建监听事件
//创建监听事件int aeCreateFileEvent(aeEventLoop *eventLoop, int fd, int mask,aeFileProc *proc, void *clientData){//判断fd大于eventloop设置的事件队列大小if (fd >= eventLoop->setsize) {errno = ERANGE;return AE_ERR;}//取出对应的aeFileEvent事件aeFileEvent *fe = &eventLoop->events[fd];//添加读写事件到不同的模型if (aeApiAddEvent(eventLoop, fd, mask) == -1)return AE_ERR;//文件类型按位或fe->mask |= mask;//根据最终的类型设置读写回调函数if (mask & AE_READABLE) fe->rfileProc = proc;if (mask & AE_WRITABLE) fe->wfileProc = proc;//fe中读写操作的clientdatafe->clientData = clientData;//如果fd大于当前最大的eventLoop maxfdfdif (fd > eventLoop->maxfd)eventLoop->maxfd = fd;return AE_OK;}
删除监听事件
void aeDeleteFileEvent(aeEventLoop *eventLoop, int fd, int mask){if (fd >= eventLoop->setsize) return;aeFileEvent *fe = &eventLoop->events[fd];if (fe->mask == AE_NONE) return;//网络模型里删除对应的事件aeApiDelEvent(eventLoop, fd, mask);//清除对应的类型标记fe->mask = fe->mask & (~mask);//如果删除的fd是maxfd，并且对应的事件为空，那么更新maxfdif (fd == eventLoop->maxfd && fe->mask == AE_NONE) {/* Update the max fd */int j;for (j = eventLoop->maxfd-1; j >= 0; j--)if (eventLoop->events[j].mask != AE_NONE) break;eventLoop->maxfd = j;}}
//获取文件类型int aeGetFileEvents(aeEventLoop *eventLoop, int fd) {if (fd >= eventLoop->setsize) return 0;aeFileEvent *fe = &eventLoop->events[fd];//返回对应的类型标记return fe->mask;}
事件派发函数
//派发事件的函数int aeProcessEvents(aeEventLoop *eventLoop, int flags){int processed = 0, numevents;/* Nothing to do? return ASAP */if (!(flags & AE_TIME_EVENTS) && !(flags & AE_FILE_EVENTS)) return 0;//为了休眠，直到有时间事件触发，即便是没有文件事件处理，我们也会//调用对应的事件时间//这部分不是很清楚，知道大体意思是设置时间，//为了aeApiPoll设置等待的时间if (eventLoop->maxfd != -1 ||((flags & AE_TIME_EVENTS) && !(flags & AE_DONT_WAIT))) {int j;aeTimeEvent *shortest = NULL;struct timeval tv, *tvp;if (flags & AE_TIME_EVENTS && !(flags & AE_DONT_WAIT))shortest = aeSearchNearestTimer(eventLoop);if (shortest) {long now_sec, now_ms;/* Calculate the time missing for the nearest* timer to fire. */aeGetTime(&now_sec, &now_ms);tvp = &tv;tvp->tv_sec = shortest->when_sec - now_sec;if (shortest->when_ms < now_ms) {tvp->tv_usec = ((shortest->when_ms+1000) - now_ms)*1000;tvp->tv_sec --;} else {tvp->tv_usec = (shortest->when_ms - now_ms)*1000;}if (tvp->tv_sec < 0) tvp->tv_sec = 0;if (tvp->tv_usec < 0) tvp->tv_usec = 0;} else {/* If we have to check for events but need to return* ASAP because of AE_DONT_WAIT we need to set the timeout* to zero */if (flags & AE_DONT_WAIT) {tv.tv_sec = tv.tv_usec = 0;tvp = &tv;} else {/* Otherwise we can block */tvp = NULL; /* wait forever */}}//调用不同的网络模型poll事件numevents = aeApiPoll(eventLoop, tvp);for (j = 0; j < numevents; j++) {//轮询处理就绪事件aeFileEvent *fe = &eventLoop->events[eventLoop->fired[j].fd];int mask = eventLoop->fired[j].mask;int fd = eventLoop->fired[j].fd;int rfired = 0;//可读就绪事件if (fe->mask & mask & AE_READABLE) {rfired = 1;fe->rfileProc(eventLoop,fd,fe->clientData,mask);}//可写就绪事件if (fe->mask & mask & AE_WRITABLE) {if (!rfired || fe->wfileProc != fe->rfileProc)fe->wfileProc(eventLoop,fd,fe->clientData,mask);}processed++;}}/* Check time events *///处理所有定时器事件if (flags & AE_TIME_EVENTS)processed += processTimeEvents(eventLoop);return processed; /* return the number of processed file/time events */}
/等待millionseconds，直到有可读或者可写事件触发int aeWait(int fd, int mask, long long milliseconds) {struct pollfd pfd;int retmask = 0, retval;memset(&pfd, 0, sizeof(pfd));pfd.fd = fd;if (mask & AE_READABLE) pfd.events |= POLLIN;if (mask & AE_WRITABLE) pfd.events |= POLLOUT;if ((retval = poll(&pfd, 1, milliseconds))== 1) {if (pfd.revents & POLLIN) retmask |= AE_READABLE;if (pfd.revents & POLLOUT) retmask |= AE_WRITABLE;if (pfd.revents & POLLERR) retmask |= AE_WRITABLE;if (pfd.revents & POLLHUP) retmask |= AE_WRITABLE;return retmask;} else {return retval;}}
//ae主函数void aeMain(aeEventLoop *eventLoop) {//stop初始为0eventLoop->stop = 0;while (!eventLoop->stop) {//调用beforesleep函数if (eventLoop->beforesleep != NULL)eventLoop->beforesleep(eventLoop);//派发所有的事件aeProcessEvents(eventLoop, AE_ALL_EVENTS);}}//获取api名字char *aeGetApiName(void) {return aeApiName();}//sleep之前的回调函数void aeSetBeforeSleepProc(aeEventLoop *eventLoop, aeBeforeSleepProc *beforesleep) {eventLoop->beforesleep = beforesleep;}
这就是ae文件里大体的几个api，其他的没理解的还在研究。
