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网络营销基础 网站策划与网上营销,app定制开发大概多少钱,网上手机网站建设计划书,济南的互联网公司ae模块是redis实现的Reactor模型的封装。它的主要代码实现集中在 ae.c 中#xff0c;另外还提供了平台相关的io多路复用的封装#xff0c;它们都实现了一套相同的poll接口#xff0c;就类似于C中提供了一个接口基类#xff0c;由针对不同平台的派生类去实现。 // 创建平台…ae模块是redis实现的Reactor模型的封装。它的主要代码实现集中在 ae.c 中另外还提供了平台相关的io多路复用的封装它们都实现了一套相同的poll接口就类似于C中提供了一个接口基类由针对不同平台的派生类去实现。 // 创建平台相关的io模型实例 static int aeApiCreate(aeEventLoop *eventLoop) // 修改可侦听的fd数量 static int aeApiResize(aeEventLoop *eventLoop, int setsize) // 释放实例 static void aeApiFree(aeEventLoop *eventLoop) // 添加或修改fd的侦听事件 static int aeApiAddEvent(aeEventLoop *eventLoop, int fd, int mask) // 删除或修改fd的侦听事件 static void aeApiDelEvent(aeEventLoop *eventLoop, int fd, int delmask) // 侦听所有fd的事件 static int aeApiPoll(aeEventLoop *eventLoop, struct timeval *tvp) // 返回使用的io模型名称 static char aeApiName(void) 实际使用的io模型会根据编译时定义的宏在 ae.c 的代码头部直接引入。 / Include the best multiplexing layer supported by this system.* The following should be ordered by performances, descending. */ // 根据不同操作系统下不同的宏选择应该使用的io复用模型 #ifdef HAVE_EVPORT #include ae_evport.c #else#ifdef HAVE_EPOLL// 对应linux#include ae_epoll.c#else#ifdef HAVE_KQUEUE// 对应BSDFreeBSD、MacOS等#include ae_kqueue.c#else// 对应Solaris#include ae_select.c#endif#endif #endif 以linux为例先来看一下ae_epoll.c的实现它的代码也比较简单 static int aeApiCreate(aeEventLoop *eventLoop) {aeApiState *state zmalloc(sizeof(aeApiState));if (!state) return -1;// 分配events数组大小state-events zmalloc(sizeof(struct epoll_event)eventLoop-setsize);if (!state-events) {zfree(state);return -1;}// 创建epoll, kernal 2.6.8 之后参数被忽略了state-epfd epoll_create(1024); / 1024 is just a hint for the kernel */if (state-epfd -1) {zfree(state-events);zfree(state);return -1;}anetCloexec(state-epfd);eventLoop-apidata state;return 0; }……static int aeApiAddEvent(aeEventLoop *eventLoop, int fd, int mask) {aeApiState state eventLoop-apidata;struct epoll_event ee {0}; / avoid valgrind warning // If the fd was already monitored for some event, we need a MOD* operation. Otherwise we need an ADD operation. /// 没注册过, 认为是添加fd到epollint op eventLoop-events[fd].mask AE_NONE ?EPOLL_CTL_ADD : EPOLL_CTL_MOD;ee.events 0;// 合并新老事件mask | eventLoop-events[fd].mask; / Merge old events */// 设置需要的事件if (mask AE_READABLE) ee.events | EPOLLIN;if (mask AE_WRITABLE) ee.events | EPOLLOUT;ee.data.fd fd;if (epoll_ctl(state-epfd,op,fd,ee) -1) return -1;return 0; }static void aeApiDelEvent(aeEventLoop *eventLoop, int fd, int delmask) {aeApiState state eventLoop-apidata;struct epoll_event ee {0}; / avoid valgrind warning /// 删除指定事件int mask eventLoop-events[fd].mask (~delmask);ee.events 0;// 设置需要的事件if (mask AE_READABLE) ee.events | EPOLLIN;if (mask AE_WRITABLE) ee.events | EPOLLOUT;ee.data.fd fd;// 没有事件执行删除否则执行修改if (mask ! AE_NONE) {epoll_ctl(state-epfd,EPOLL_CTL_MOD,fd,ee);} else {/ Note, Kernel 2.6.9 requires a non null event pointer even for* EPOLL_CTL_DEL. */epoll_ctl(state-epfd,EPOLL_CTL_DEL,fd,ee);} }static int aeApiPoll(aeEventLoop *eventLoop, struct timeval *tvp) {aeApiState *state eventLoop-apidata;int retval, numevents 0;// 此处的 (tvp-tv_usec 999)/1000 是为了避免当 tvp-tv_usec 1000us 时转换成毫秒为 0ms, 导致epoll_wait不会等待// 因此这么写之后能保证只要 tvp-tv_usec 不为0那么至少都能等待 1ms 时长retval epoll_wait(state-epfd,state-events,eventLoop-setsize,tvp ? (tvp-tv_sec*1000 (tvp-tv_usec 999)/1000) : -1);if (retval 0) {int j;numevents retval;for (j 0; j numevents; j) {int mask 0;struct epoll_event e state-eventsj;if (e-events EPOLLIN) mask | AE_READABLE;if (e-events EPOLLOUT) mask | AE_WRITABLE;if (e-events EPOLLERR) mask | AE_WRITABLE|AE_READABLE;if (e-events EPOLLHUP) mask | AE_WRITABLE|AE_READABLE;// 保存触发的事件eventLoop-fired[j].fd e-data.fd;eventLoop-fired[j].mask mask;}} else if (retval -1 errno ! EINTR) {panic(aeApiPoll: epoll_wait, %s, strerror(errno));}return numevents; } 接下来再看一下ae相关接口先看下fd相关实现。 主要结构体定义如下 / File event structure / typedef struct aeFileEvent {int mask; / one of AE_(READABLE|WRITABLE|BARRIER) */ // 事件类型aeFileProc *rfileProc; // 读事件回调aeFileProc *wfileProc; // 写事件回调void clientData; // 上下文指针 } aeFileEvent;/ Time event structure / typedef struct aeTimeEvent {long long id; / time event identifier. */ // 定时器事件idmonotime when; // 触发时间aeTimeProc *timeProc; // 定时器触发回调aeEventFinalizerProc *finalizerProc; // 定时器销毁时执行的回调void *clientData; // 上下文指针struct aeTimeEvent *prev; // 前一个定时器事件struct aeTimeEvent next; // 后一个定时器事件int refcount; / refcount to prevent timer events from being* freed in recursive time event calls. / // 引用计数 } aeTimeEvent;/ A fired event / typedef struct aeFiredEvent {int fd; // 触发事件的定时器int mask; // 触发的事件类型 } aeFiredEvent;/ State of an event based program / typedef struct aeEventLoop {int maxfd; / highest file descriptor currently registered / // 注册的最大fd值int setsize; / max number of file descriptors tracked */ // 注册的fd数量long long timeEventNextId; // 自增用于生成定时器idaeFileEvent events; / Registered events */ // 注册的fd事件aeFiredEvent fired; / Fired events */ // 触发的fd事件aeTimeEvent *timeEventHead; // 定时器事件链表头int stop; // 结束标志void apidata; / This is used for polling API specific data */ // 不同poll的上下文信息aeBeforeSleepProc *beforesleep; // poll前调用aeBeforeSleepProc *aftersleep; // poll后调用int flags; } aeEventLoop; aeEventLoop中的events是用于保存fd注册事件的数组它是以fd值作为索引来存取事件的。 创建eventloop事件管理器 aeEventLoop *aeCreateEventLoop(int setsize) {aeEventLoop eventLoop;int i;// 初始化一下单调时钟使用哪种方式实现monotonicInit(); / just in case the calling app didnt initialize */if ((eventLoop zmalloc(sizeof(*eventLoop))) NULL) goto err;// events、fired数组以fd值为下标直接存取对应fd的相关数据eventLoop-events zmalloc(sizeof(aeFileEvent)*setsize);eventLoop-fired zmalloc(sizeof(aeFiredEvent)setsize);if (eventLoop-events NULL || eventLoop-fired NULL) goto err;eventLoop-setsize setsize;eventLoop-timeEventHead NULL;eventLoop-timeEventNextId 0;eventLoop-stop 0;eventLoop-maxfd -1;eventLoop-beforesleep NULL;eventLoop-aftersleep NULL;eventLoop-flags 0;// 根据平台创建io模型实例if (aeApiCreate(eventLoop) -1) goto err;/ Events with mask AE_NONE are not set. So lets initialize the* vector with it. */for (i 0; i setsize; i)eventLoop-events[i].mask AE_NONE;return eventLoop;err:if (eventLoop) {zfree(eventLoop-events);zfree(eventLoop-fired);zfree(eventLoop);}return NULL; } 添加和删除事件 int aeCreateFileEvent(aeEventLoop *eventLoop, int fd, int mask,aeFileProc *proc, void *clientData) {// 超出events数组有效范围直接报错if (fd eventLoop-setsize) {errno ERANGE;return AE_ERR;}aeFileEvent *fe eventLoop-events[fd];// 添加或修改fd读写事件if (aeApiAddEvent(eventLoop, fd, mask) -1)return AE_ERR;fe-mask | mask;if (mask AE_READABLE) fe-rfileProc proc;if (mask AE_WRITABLE) fe-wfileProc proc;fe-clientData clientData;if (fd eventLoop-maxfd)eventLoop-maxfd fd;return AE_OK; }void aeDeleteFileEvent(aeEventLoop *eventLoop, int fd, int mask) {if (fd eventLoop-setsize) return;aeFileEvent fe eventLoop-events[fd];if (fe-mask AE_NONE) return;/ We want to always remove AE_BARRIER if set when AE_WRITABLE* is removed. /if (mask AE_WRITABLE) mask | AE_BARRIER;aeApiDelEvent(eventLoop, fd, mask);fe-mask fe-mask (~mask);// 如果本次删除事件的fd是最大的fd并且该fd已经没有事件了可以认为该fd被清除了if (fd eventLoop-maxfd fe-mask AE_NONE) {/ Update the max fd */int j;// 从后往前遍历找到第一个有事件的fd赋给maxfdfor (j eventLoop-maxfd-1; j 0; j–)if (eventLoop-events[j].mask ! AE_NONE) break;eventLoop-maxfd j;} } 事件处理函数处理一轮事件 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;/ Note that we want to call select() even if there are no* file events to process as long as we want to process time* events, in order to sleep until the next time event is ready* to fire. */if (eventLoop-maxfd ! -1 ||((flags AE_TIME_EVENTS) !(flags AE_DONT_WAIT))) {int j;struct timeval tv, tvp;int64_t usUntilTimer -1;// 获取最近的一个定时器距当前时间的触发时长if (flags AE_TIME_EVENTS !(flags AE_DONT_WAIT))usUntilTimer usUntilEarliestTimer(eventLoop);if (usUntilTimer 0) {tv.tv_sec usUntilTimer / 1000000;tv.tv_usec usUntilTimer % 1000000;tvp tv;} 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 /}}// 不需要等待超时时间设为0if (eventLoop-flags AE_DONT_WAIT) {tv.tv_sec tv.tv_usec 0;tvp tv;}// 执行poll前的回调(对fd读写以及命令处理都会在beforsleep中执行, 如果开启多线程读写也会在它内部一并处理)if (eventLoop-beforesleep ! NULL flags AE_CALL_BEFORE_SLEEP)eventLoop-beforesleep(eventLoop);/ Call the multiplexing API, will return only on timeout or when* some event fires. /// 等待事件numevents aeApiPoll(eventLoop, tvp);/ After sleep callback. */// 执行poll后的回调if (eventLoop-aftersleep ! NULL flags AE_CALL_AFTER_SLEEP)eventLoop-aftersleep(eventLoop);// 处理poll到的读写事件for (j 0; j numevents; j) {int fd eventLoop-fired[j].fd;aeFileEvent fe eventLoop-events[fd];int mask eventLoop-fired[j].mask;int fired 0; / Number of events fired for current fd. // Normally we execute the readable event first, and the writable* event later. This is useful as sometimes we may be able* to serve the reply of a query immediately after processing the* query.** However if AE_BARRIER is set in the mask, our application is* asking us to do the reverse: never fire the writable event* after the readable. In such a case, we invert the calls.* This is useful when, for instance, we want to do things* in the beforeSleep() hook, like fsyncing a file to disk,* before replying to a client. /// 是否反转读写事件的顺序不设置 AE_BARRIER 时先读后写int invert fe-mask AE_BARRIER;/ Note the fe-mask mask … code: maybe an already* processed event removed an element that fired and we still* didnt processed, so we check if the event is still valid.** Fire the readable event if the call sequence is not* inverted. /if (!invert fe-mask mask AE_READABLE) {// 处理读事件回调fe-rfileProc(eventLoop,fd,fe-clientData,mask);fired;// 防止在事件处理函数中 resize 过数组大小所以需要重新获取下地址fe eventLoop-events[fd]; / Refresh in case of resize. /}/ Fire the writable event. /if (fe-mask mask AE_WRITABLE) {// 处理写事件回调读写回调函数相同时每轮poll只执行一次读或者写回调if (!fired || fe-wfileProc ! fe-rfileProc) {fe-wfileProc(eventLoop,fd,fe-clientData,mask);fired;}}/ If we have to invert the call, fire the readable event now* after the writable one. /if (invert) {// 反转读写时先写然后在这边后读读写回调函数相同时每轮poll只执行一次读或者写回调fe eventLoop-events[fd]; / Refresh in case of resize. /if ((fe-mask mask AE_READABLE) (!fired || fe-wfileProc ! fe-rfileProc)){fe-rfileProc(eventLoop,fd,fe-clientData,mask);fired;}}processed;}}/ Check time events /// 处理定时器事件if (flags AE_TIME_EVENTS)processed processTimeEvents(eventLoop);return processed; / return the number of processed file/time events */ } 执行主事件循环 void aeMain(aeEventLoop *eventLoop) {// 启动事件循环eventLoop-stop 0;while (!eventLoop-stop) {// 处理事件aeProcessEvents(eventLoop, AE_ALL_EVENTS|AE_CALL_BEFORE_SLEEP|AE_CALL_AFTER_SLEEP);} }