/* A simple event-driven programming library. Originally I wrote this code
* for the Jim's event-loop (Jim is a Tcl interpreter) but later translated
* it in form of a library for easy reuse.
*
* Copyright (c) 2006-2010, Salvatore Sanfilippo <antirez at gmail dot com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Redis nor the names of its contributors may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdio.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <poll.h>
#include <string.h>
#include <time.h>
#include <errno.h>
#include "ae.h"
#include "zmalloc.h"
#include "config.h"
/* Include the best multiplexing layer supported by this system.
* The following should be ordered by performances, descending. */
#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
aeEventLoop *aeCreateEventLoop(int setsize) {
aeEventLoop *eventLoop;
int i;
if ((eventLoop = zmalloc(sizeof(*eventLoop))) == NULL) goto err;
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->lastTime = time(NULL);
eventLoop->timeEventHead = NULL;
eventLoop->timeEventNextId = 0;
eventLoop->stop = 0;
eventLoop->maxfd = -1;
eventLoop->beforesleep = NULL;
eventLoop->aftersleep = NULL;
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++)
eventLoop->events[i].mask = AE_NONE;
return eventLoop;
err:
if (eventLoop) {
zfree(eventLoop->events);
zfree(eventLoop->fired);
zfree(eventLoop);
}
return NULL;
}
/* Return the current set size. */
int aeGetSetSize(aeEventLoop *eventLoop) {
return eventLoop->setsize;
}
/* Resize the maximum set size of the event loop.
* If the requested set size is smaller than the current set size, but
* there is already a file descriptor in use that is >= the requested
* set size minus one, AE_ERR is returned and the operation is not
* performed at all.
*
* Otherwise AE_OK is returned and the operation is successful. */
int aeResizeSetSize(aeEventLoop *eventLoop, int setsize) {
int i;
if (setsize == eventLoop->setsize) return AE_OK;
if (eventLoop->maxfd >= setsize) return AE_ERR;
if (aeApiResize(eventLoop,setsize) == -1) return AE_ERR;
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. */
for (i = eventLoop->maxfd+1; i < setsize; i++)
eventLoop->events[i].mask = AE_NONE;
return AE_OK;
}
void aeDeleteEventLoop(aeEventLoop *eventLoop) {
aeApiFree(eventLoop);
zfree(eventLoop->events);
zfree(eventLoop->fired);
zfree(eventLoop);
}
void aeStop(aeEventLoop *eventLoop) {
eventLoop->stop = 1;
}
int aeCreateFileEvent(aeEventLoop *eventLoop, int fd, int mask,
aeFileProc *proc, void *clientData)
{
if (fd >= eventLoop->setsize) {
errno = ERANGE;
return AE_ERR;
}
aeFileEvent *fe = &eventLoop->events[fd];
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);
if (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;
}
}
int aeGetFileEvents(aeEventLoop *eventLoop, int fd) {
if (fd >= eventLoop->setsize) return 0;
aeFileEvent *fe = &eventLoop->events[fd];
return fe->mask;
}
static void aeGetTime(long *seconds, long *milliseconds)
{
struct timeval tv;
gettimeofday(&tv, NULL);
*seconds = tv.tv_sec;
*milliseconds = tv.tv_usec/1000;
}
static void aeAddMillisecondsToNow(long long milliseconds, long *sec, long *ms) {
long cur_sec, cur_ms, when_sec, when_ms;
aeGetTime(&cur_sec, &cur_ms);
when_sec = cur_sec + milliseconds/1000;
when_ms = cur_ms + milliseconds%1000;
if (when_ms >= 1000) {
when_sec ++;
when_ms -= 1000;
}
*sec = when_sec;
*ms = when_ms;
}
long long aeCreateTimeEvent(aeEventLoop *eventLoop, long long milliseconds,
aeTimeProc *proc, void *clientData,
aeEventFinalizerProc *finalizerProc)
{
long long id = eventLoop->timeEventNextId++;
aeTimeEvent *te;
te = zmalloc(sizeof(*te));
if (te == NULL) return AE_ERR;
te->id = id;
aeAddMillisecondsToNow(milliseconds,&te->when_sec,&te->when_ms);
te->timeProc = proc;
te->finalizerProc = finalizerProc;
te->clientData = clientData;
te->prev = NULL;
te->next = eventLoop->timeEventHead;
if (te->next)
te->next->prev = te;
eventLoop->timeEventHead = te;
return id;
}
int aeDeleteTimeEvent(aeEventLoop *eventLoop, long long id)
{
aeTimeEvent *te = eventLoop->timeEventHead;
while(te) {
if (te->id == id) {
te->id = AE_DELETED_EVENT_ID;
return AE_OK;
}
te = te->next;
}
return AE_ERR; /* NO event with the specified ID found */
}
/* Search the first timer to fire.
* This operation is useful to know how many time the select can be
* put in sleep without to delay any event.
* If there are no timers NULL is returned.
*
* Note that's O(N) since time events are unsorted.
* Possible optimizations (not needed by Redis so far, but...):
* 1) Insert the event in order, so that the nearest is just the head.
* Much better but still insertion or deletion of timers is O(N).
* 2) Use a skiplist to have this operation as O(1) and insertion as O(log(N)).
*/
static aeTimeEvent *aeSearchNearestTimer(aeEventLoop *eventLoop)
{
aeTimeEvent *te = eventLoop->timeEventHead;
aeTimeEvent *nearest = NULL;
while(te) {
if (!nearest || te->when_sec < nearest->when_sec ||
(te->when_sec == nearest->when_sec &&
te->when_ms < nearest->when_ms))
nearest = te;
te = te->next;
}
return nearest;
}
/* Process time events */
static int processTimeEvents(aeEventLoop *eventLoop) {
int processed = 0;
aeTimeEvent *te;
long long maxId;
time_t now = time(NULL);
/* If the system clock is moved to the future, and then set back to the
* right value, time events may be delayed in a random way. Often this
* means that scheduled operations will not be performed soon enough.
*
* Here we try to detect system clock skews, and force all the time
* events to be processed ASAP when this happens: the idea is that
* processing events earlier is less dangerous than delaying them
* indefinitely, and practice suggests it is. */
if (now < eventLoop->lastTime) {
te = eventLoop->timeEventHead;
while(te) {
te->when_sec = 0;
te = te->next;
}
}
eventLoop->lastTime = now;
te = eventLoop->timeEventHead;
maxId = eventLoop->timeEventNextId-1;
while(te) {
long now_sec, now_ms;
long long id;
/* Remove events scheduled for deletion. */
if (te->id == AE_DELETED_EVENT_ID) {
aeTimeEvent *next = te->next;
if (te->prev)
te->prev->next = te->next;
else
eventLoop->timeEventHead = te->next;
if (te->next)
te->next->prev = te->prev;
if (te->finalizerProc)
te->finalizerProc(eventLoop, te->clientData);
zfree(te);
te = next;
continue;
}
/* Make sure we don't process time events created by time events in
* this iteration. Note that this check is currently useless: we always
* add new timers on the head, however if we change the implementation
* detail, this check may be useful again: we keep it here for future
* defense. */
if (te->id > maxId) {
te = te->next;
continue;
}
aeGetTime(&now_sec, &now_ms);
if (now_sec > te->when_sec ||
(now_sec == te->when_sec && now_ms >= te->when_ms))
{
int retval;
id = te->id;
retval = te->timeProc(eventLoop, id, te->clientData);
processed++;
if (retval != AE_NOMORE) {
aeAddMillisecondsToNow(retval,&te->when_sec,&te->when_ms);
} else {
te->id = AE_DELETED_EVENT_ID;
}
}
te = te->next;
}
return processed;
}
/* Process every pending time event, then every pending file event
* (that may be registered by time event callbacks just processed).
* Without special flags the function sleeps until some file event
* fires, or when the next time event occurs (if any).
*
* If flags is 0, the function does nothing and returns.
* if flags has AE_ALL_EVENTS set, all the kind of events are processed.
* if flags has AE_FILE_EVENTS set, file events are processed.
* if flags has AE_TIME_EVENTS set, time events are processed.
* if flags has AE_DONT_WAIT set the function returns ASAP until all
* if flags has AE_CALL_AFTER_SLEEP set, the aftersleep callback is called.
* the events that's possible to process without to wait are processed.
*
* The function returns the number of events processed. */
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 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;
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;
aeGetTime(&now_sec, &now_ms);
tvp = &tv;
/* How many milliseconds we need to wait for the next
* time event to fire? */
long long ms =
(shortest->when_sec - now_sec)*1000 +
shortest->when_ms - now_ms;
if (ms > 0) {
tvp->tv_sec = ms/1000;
tvp->tv_usec = (ms % 1000)*1000;
} else {
tvp->tv_sec = 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 */
}
}
/* Call the multiplexing API, will return only on timeout or when
* some event fires. */
numevents = aeApiPoll(eventLoop, tvp);
/* After sleep callback. */
if (eventLoop->aftersleep != NULL && flags & AE_CALL_AFTER_SLEEP)
eventLoop->aftersleep(eventLoop);
for (j = 0; j < numevents; j++) {
aeFileEvent *fe = &eventLoop->events[eventLoop->fired[j].fd];
int mask = eventLoop->fired[j].mask;
int fd = eventLoop->fired[j].fd;
int fired = 0; /* Number of events fired for current fd. */
/* Normally we execute the readable event first, and the writable
* event laster. 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 fsynching a file to disk,
* before replying to a client. */
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
* didn't 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) {
fe->rfileProc(eventLoop,fd,fe->clientData,mask);
fired++;
}
/* Fire the writable event. */
if (fe->mask & mask & AE_WRITABLE) {
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 && fe->mask & mask & AE_READABLE) {
if (!fired || fe->wfileProc != fe->rfileProc) {
fe->rfileProc(eventLoop,fd,fe->clientData,mask);
fired++;
}
}
processed++;
}
}
/* Check time events */
if (flags & AE_TIME_EVENTS)
processed += processTimeEvents(eventLoop);
return processed; /* return the number of processed file/time events */
}
/* Wait for milliseconds until the given file descriptor becomes
* writable/readable/exception */
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;
}
}
void aeMain(aeEventLoop *eventLoop) {
eventLoop->stop = 0;
while (!eventLoop->stop) {
if (eventLoop->beforesleep != NULL)
eventLoop->beforesleep(eventLoop);
aeProcessEvents(eventLoop, AE_ALL_EVENTS|AE_CALL_AFTER_SLEEP);
}
}
char *aeGetApiName(void) {
return aeApiName();
}
void aeSetBeforeSleepProc(aeEventLoop *eventLoop, aeBeforeSleepProc *beforesleep) {
eventLoop->beforesleep = beforesleep;
}
void aeSetAfterSleepProc(aeEventLoop *eventLoop, aeBeforeSleepProc *aftersleep) {
eventLoop->aftersleep = aftersleep;
}
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