漫话Redis源码之八十三

2024-02-06 09:38
文章标签 源码 redis 漫话 八十三

本文主要是介绍漫话Redis源码之八十三，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

触发并掩码掉给定的fd：

static int aeApiLookupPending(aeApiState *state, int fd) {uint_t i;for (i = 0; i < state->npending; i++) {if (state->pending_fds[i] == fd)return (i);}return (-1);
}/** Helper function to invoke port_associate for the given fd and mask.*/
static int aeApiAssociate(const char *where, int portfd, int fd, int mask) {int events = 0;int rv, err;if (mask & AE_READABLE)events |= POLLIN;if (mask & AE_WRITABLE)events |= POLLOUT;if (evport_debug)fprintf(stderr, "%s: port_associate(%d, 0x%x) = ", where, fd, events);rv = port_associate(portfd, PORT_SOURCE_FD, fd, events,(void *)(uintptr_t)mask);err = errno;if (evport_debug)fprintf(stderr, "%d (%s)\n", rv, rv == 0 ? "no error" : strerror(err));if (rv == -1) {fprintf(stderr, "%s: port_associate: %s\n", where, strerror(err));if (err == EAGAIN)fprintf(stderr, "aeApiAssociate: event port limit exceeded.");}return rv;
}static int aeApiAddEvent(aeEventLoop *eventLoop, int fd, int mask) {aeApiState *state = eventLoop->apidata;int fullmask, pfd;if (evport_debug)fprintf(stderr, "aeApiAddEvent: fd %d mask 0x%x\n", fd, mask);/** Since port_associate's "events" argument replaces any existing events, we* must be sure to include whatever events are already associated when* we call port_associate() again.*/fullmask = mask | eventLoop->events[fd].mask;pfd = aeApiLookupPending(state, fd);if (pfd != -1) {/** This fd was recently returned from aeApiPoll.  It should be safe to* assume that the consumer has processed that poll event, but we play* it safer by simply updating pending_mask.  The fd will be* re-associated as usual when aeApiPoll is called again.*/if (evport_debug)fprintf(stderr, "aeApiAddEvent: adding to pending fd %d\n", fd);state->pending_masks[pfd] |= fullmask;return 0;}return (aeApiAssociate("aeApiAddEvent", state->portfd, fd, fullmask));
}static void aeApiDelEvent(aeEventLoop *eventLoop, int fd, int mask) {aeApiState *state = eventLoop->apidata;int fullmask, pfd;if (evport_debug)fprintf(stderr, "del fd %d mask 0x%x\n", fd, mask);pfd = aeApiLookupPending(state, fd);if (pfd != -1) {if (evport_debug)fprintf(stderr, "deleting event from pending fd %d\n", fd);/** This fd was just returned from aeApiPoll, so it's not currently* associated with the port.  All we need to do is update* pending_mask appropriately.*/state->pending_masks[pfd] &= ~mask;if (state->pending_masks[pfd] == AE_NONE)state->pending_fds[pfd] = -1;return;}/** The fd is currently associated with the port.  Like with the add case* above, we must look at the full mask for the file descriptor before* updating that association.  We don't have a good way of knowing what the* events are without looking into the eventLoop state directly.  We rely on* the fact that our caller has already updated the mask in the eventLoop.*/fullmask = eventLoop->events[fd].mask;if (fullmask == AE_NONE) {/** We're removing *all* events, so use port_dissociate to remove the* association completely.  Failure here indicates a bug.*/if (evport_debug)fprintf(stderr, "aeApiDelEvent: port_dissociate(%d)\n", fd);if (port_dissociate(state->portfd, PORT_SOURCE_FD, fd) != 0) {perror("aeApiDelEvent: port_dissociate");abort(); /* will not return */}} else if (aeApiAssociate("aeApiDelEvent", state->portfd, fd,fullmask) != 0) {/** ENOMEM is a potentially transient condition, but the kernel won't* generally return it unless things are really bad.  EAGAIN indicates* we've reached a resource limit, for which it doesn't make sense to* retry (counter-intuitively).  All other errors indicate a bug.  In any* of these cases, the best we can do is to abort.*/abort(); /* will not return */}
}static int aeApiPoll(aeEventLoop *eventLoop, struct timeval *tvp) {aeApiState *state = eventLoop->apidata;struct timespec timeout, *tsp;uint_t mask, i;uint_t nevents;port_event_t event[MAX_EVENT_BATCHSZ];/** If we've returned fd events before, we must re-associate them with the* port now, before calling port_get().  See the block comment at the top of* this file for an explanation of why.*/for (i = 0; i < state->npending; i++) {if (state->pending_fds[i] == -1)/* This fd has since been deleted. */continue;if (aeApiAssociate("aeApiPoll", state->portfd,state->pending_fds[i], state->pending_masks[i]) != 0) {/* See aeApiDelEvent for why this case is fatal. */abort();}state->pending_masks[i] = AE_NONE;state->pending_fds[i] = -1;}state->npending = 0;if (tvp != NULL) {timeout.tv_sec = tvp->tv_sec;timeout.tv_nsec = tvp->tv_usec * 1000;tsp = &timeout;} else {tsp = NULL;}/** port_getn can return with errno == ETIME having returned some events (!).* So if we get ETIME, we check nevents, too.*/nevents = 1;if (port_getn(state->portfd, event, MAX_EVENT_BATCHSZ, &nevents,tsp) == -1 && (errno != ETIME || nevents == 0)) {if (errno == ETIME || errno == EINTR)return 0;/* Any other error indicates a bug. */perror("aeApiPoll: port_get");abort();}state->npending = nevents;for (i = 0; i < nevents; i++) {mask = 0;if (event[i].portev_events & POLLIN)mask |= AE_READABLE;if (event[i].portev_events & POLLOUT)mask |= AE_WRITABLE;eventLoop->fired[i].fd = event[i].portev_object;eventLoop->fired[i].mask = mask;if (evport_debug)fprintf(stderr, "aeApiPoll: fd %d mask 0x%x\n",(int)event[i].portev_object, mask);state->pending_fds[i] = event[i].portev_object;state->pending_masks[i] = (uintptr_t)event[i].portev_user;}return nevents;
}static char *aeApiName(void) {return "evport";
}

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