Add an option to trigger bufferevent I/O callbacks

bufferevent-internal.h

@@ -341,14 +341,20 @@ int bufferevent_decref_and_unlock_(struct bufferevent *bufev);
 
 /** Internal: If callbacks are deferred and we have a read callback, schedule
  * a readcb.  Otherwise just run the readcb. */
-void bufferevent_run_readcb_(struct bufferevent *bufev);
+void bufferevent_run_readcb_(struct bufferevent *bufev, int options);
 /** Internal: If callbacks are deferred and we have a write callback, schedule
  * a writecb.  Otherwise just run the writecb. */
-void bufferevent_run_writecb_(struct bufferevent *bufev);
+void bufferevent_run_writecb_(struct bufferevent *bufev, int options);
 /** Internal: If callbacks are deferred and we have an eventcb, schedule
  * it to run with events "what".  Otherwise just run the eventcb. */
 void bufferevent_run_eventcb_(struct bufferevent *bufev, short what);
 
+/** Internal: Run or schedule (if deferred or options contain
+ * BEV_TRIG_DEFER_CALLBACKS) I/O callbacks specified in iotype.
+ * Must already hold the bufev lock. */
+void bufferevent_trigger_nolock_(struct bufferevent *bufev, short iotype, int options);
+
+
 /** Internal: Add the event 'ev' with timeout tv, unless tv is set to 0, in
  * which case add ev with no timeout. */
 int bufferevent_add_event_(struct event *ev, const struct timeval *tv);

bufferevent.c

@@ -219,14 +219,15 @@ bufferevent_run_deferred_callbacks_unlocked(struct event_callback *cb, void *arg
 
 
 void
-bufferevent_run_readcb_(struct bufferevent *bufev)
+bufferevent_run_readcb_(struct bufferevent *bufev, int options)
 {
 	/* Requires that we hold the lock and a reference */
 	struct bufferevent_private *p =
 	    EVUTIL_UPCAST(bufev, struct bufferevent_private, bev);
 	if (bufev->readcb == NULL)
 		return;
-	if (p->options & BEV_OPT_DEFER_CALLBACKS) {
+	if ((p->options & BEV_OPT_DEFER_CALLBACKS) ||
+	    (options & BEV_TRIG_DEFER_CALLBACKS)) {
 		p->readcb_pending = 1;
 		SCHEDULE_DEFERRED(p);
 	} else {
@@ -235,21 +236,41 @@ bufferevent_run_readcb_(struct bufferevent *bufev)
 }
 
 void
-bufferevent_run_writecb_(struct bufferevent *bufev)
+bufferevent_run_writecb_(struct bufferevent *bufev, int options)
 {
 	/* Requires that we hold the lock and a reference */
 	struct bufferevent_private *p =
 	    EVUTIL_UPCAST(bufev, struct bufferevent_private, bev);
 	if (bufev->writecb == NULL)
 		return;
-	if (p->options & BEV_OPT_DEFER_CALLBACKS) {
+	if ((p->options & BEV_OPT_DEFER_CALLBACKS) ||
+	    (options & BEV_TRIG_DEFER_CALLBACKS)) {
 		p->writecb_pending = 1;
 		SCHEDULE_DEFERRED(p);
 	} else {
 		bufev->writecb(bufev, bufev->cbarg);
 	}
 }
 
+void
+bufferevent_trigger_nolock_(struct bufferevent *bufev, short iotype, int options)
+{
+	if ((iotype & EV_READ) && ((options & BEV_TRIG_IGNORE_WATERMARKS) ||
+	    evbuffer_get_length(bufev->input) >= bufev->wm_read.low))
+		bufferevent_run_readcb_(bufev, options);
+	if ((iotype & EV_WRITE) && ((options & BEV_TRIG_IGNORE_WATERMARKS) ||
+	    evbuffer_get_length(bufev->output) <= bufev->wm_write.low))
+		bufferevent_run_writecb_(bufev, options);
+}
+
+void
+bufferevent_trigger(struct bufferevent *bufev, short iotype, int options)
+{
+	bufferevent_incref_and_lock_(bufev);
+	bufferevent_trigger_nolock_(bufev, iotype, options);
+	bufferevent_decref_and_unlock_(bufev);
+}
+
 void
 bufferevent_run_eventcb_(struct bufferevent *bufev, short what)
 {
@@ -322,20 +343,18 @@ bufferevent_init_common_(struct bufferevent_private *bufev_private,
 		event_warnx("UNLOCK_CALLBACKS requires DEFER_CALLBACKS");
 		return -1;
 	}
-	if (options & BEV_OPT_DEFER_CALLBACKS) {
-		if (options & BEV_OPT_UNLOCK_CALLBACKS)
-			event_deferred_cb_init_(
-			    &bufev_private->deferred,
-			    event_base_get_npriorities(base) / 2,
-			    bufferevent_run_deferred_callbacks_unlocked,
-			    bufev_private);
-		else
-			event_deferred_cb_init_(
-			    &bufev_private->deferred,
-			    event_base_get_npriorities(base) / 2,
-			    bufferevent_run_deferred_callbacks_locked,
-			    bufev_private);
-	}
+	if (options & BEV_OPT_UNLOCK_CALLBACKS)
+		event_deferred_cb_init_(
+		    &bufev_private->deferred,
+		    event_base_get_npriorities(base) / 2,
+		    bufferevent_run_deferred_callbacks_unlocked,
+		    bufev_private);
+	else
+		event_deferred_cb_init_(
+		    &bufev_private->deferred,
+		    event_base_get_npriorities(base) / 2,
+		    bufferevent_run_deferred_callbacks_locked,
+		    bufev_private);
 
 	bufev_private->options = options;
 

bufferevent_async.c

@@ -458,8 +458,7 @@ read_complete(struct event_overlapped *eo, ev_uintptr_t key,
 	if (bev_a->ok) {
 		if (ok && nbytes) {
 			BEV_RESET_GENERIC_READ_TIMEOUT(bev);
-			if (evbuffer_get_length(bev->input) >= bev->wm_read.low)
-				bufferevent_run_readcb_(bev);
+			bufferevent_trigger_nolock_(bev, EV_READ, 0);
 			bev_async_consider_reading(bev_a);
 		} else if (!ok) {
 			what |= BEV_EVENT_ERROR;
@@ -502,9 +501,7 @@ write_complete(struct event_overlapped *eo, ev_uintptr_t key,
 	if (bev_a->ok) {
 		if (ok && nbytes) {
 			BEV_RESET_GENERIC_WRITE_TIMEOUT(bev);
-			if (evbuffer_get_length(bev->output) <=
-			    bev->wm_write.low)
-				bufferevent_run_writecb_(bev);
+			bufferevent_trigger_nolock_(bev, EV_WRITE, 0);
 			bev_async_consider_writing(bev_a);
 		} else if (!ok) {
 			what |= BEV_EVENT_ERROR;

bufferevent_filter.c

@@ -376,10 +376,9 @@ be_filter_process_output(struct bufferevent_filtered *bevf,
 			/* Or if we have filled the underlying output buffer. */
 			!be_underlying_writebuf_full(bevf,state));
 
-		if (processed &&
-		    evbuffer_get_length(bufev->output) <= bufev->wm_write.low) {
+		if (processed) {
 			/* call the write callback.*/
-			bufferevent_run_writecb_(bufev);
+			bufferevent_trigger_nolock_(bufev, EV_WRITE, 0);
 
 			if (res == BEV_OK &&
 			    (bufev->enabled & EV_WRITE) &&
@@ -442,9 +441,8 @@ be_filter_readcb(struct bufferevent *underlying, void *me_)
 	/* XXX This should be in process_input, not here.  There are
 	 * other places that can call process-input, and they should
 	 * force readcb calls as needed. */
-	if (processed_any &&
-	    evbuffer_get_length(bufev->input) >= bufev->wm_read.low)
-		bufferevent_run_readcb_(bufev);
+	if (processed_any)
+		bufferevent_trigger_nolock_(bufev, EV_READ, 0);
 
 	bufferevent_decref_and_unlock_(bufev);
 }

bufferevent_openssl.c

@@ -709,8 +709,7 @@ do_write(struct bufferevent_openssl *bev_ssl, int atmost)
 		if (bev_ssl->underlying)
 			BEV_RESET_GENERIC_WRITE_TIMEOUT(bev);
 
-		if (evbuffer_get_length(output) <= bev->wm_write.low)
-			bufferevent_run_writecb_(bev);
+		bufferevent_trigger_nolock_(bev, EV_WRITE, 0);
 	}
 	return result;
 }
@@ -824,11 +823,8 @@ consider_reading(struct bufferevent_openssl *bev_ssl)
 
 	if (all_result_flags & OP_MADE_PROGRESS) {
 		struct bufferevent *bev = &bev_ssl->bev.bev;
-		struct evbuffer *input = bev->input;
 
-		if (evbuffer_get_length(input) >= bev->wm_read.low) {
-			bufferevent_run_readcb_(bev);
-		}
+		bufferevent_trigger_nolock_(bev, EV_READ, 0);
 	}
 
 	if (!bev_ssl->underlying) {
@@ -852,11 +848,8 @@ consider_writing(struct bufferevent_openssl *bev_ssl)
 		r = do_read(bev_ssl, 1024); /* XXXX 1024 is a hack */
 		if (r & OP_MADE_PROGRESS) {
 			struct bufferevent *bev = &bev_ssl->bev.bev;
-			struct evbuffer *input = bev->input;
 
-			if (evbuffer_get_length(input) >= bev->wm_read.low) {
-				bufferevent_run_readcb_(bev);
-			}
+			bufferevent_trigger_nolock_(bev, EV_READ, 0);
 		}
 		if (r & (OP_ERR|OP_BLOCKED))
 			break;

bufferevent_pair.c

@@ -151,7 +151,7 @@ static void
 be_pair_transfer(struct bufferevent *src, struct bufferevent *dst,
     int ignore_wm)
 {
-	size_t src_size, dst_size;
+	size_t dst_size;
 	size_t n;
 
 	evbuffer_unfreeze(src->output, 1);
@@ -182,15 +182,8 @@ be_pair_transfer(struct bufferevent *src, struct bufferevent *dst,
 			BEV_DEL_GENERIC_WRITE_TIMEOUT(dst);
 	}
 
-	src_size = evbuffer_get_length(src->output);
-	dst_size = evbuffer_get_length(dst->input);
-
-	if (dst_size >= dst->wm_read.low) {
-		bufferevent_run_readcb_(dst);
-	}
-	if (src_size <= src->wm_write.low) {
-		bufferevent_run_writecb_(src);
-	}
+	bufferevent_trigger_nolock_(dst, EV_READ, 0);
+	bufferevent_trigger_nolock_(src, EV_WRITE, 0);
 done:
 	evbuffer_freeze(src->output, 1);
 	evbuffer_freeze(dst->input, 0);

bufferevent_sock.c

@@ -184,8 +184,7 @@ bufferevent_readcb(evutil_socket_t fd, short event, void *arg)
 	bufferevent_decrement_read_buckets_(bufev_p, res);
 
 	/* Invoke the user callback - must always be called last */
-	if (evbuffer_get_length(input) >= bufev->wm_read.low)
-		bufferevent_run_readcb_(bufev);
+	bufferevent_trigger_nolock_(bufev, EV_READ, 0);
 
 	goto done;
 
@@ -294,9 +293,8 @@ bufferevent_writecb(evutil_socket_t fd, short event, void *arg)
 	 * Invoke the user callback if our buffer is drained or below the
 	 * low watermark.
 	 */
-	if ((res || !connected) &&
-	    evbuffer_get_length(bufev->output) <= bufev->wm_write.low) {
-		bufferevent_run_writecb_(bufev);
+	if (res || !connected) {
+		bufferevent_trigger_nolock_(bufev, EV_WRITE, 0);
 	}
 
 	goto done;

include/event2/bufferevent.h

@@ -558,6 +558,32 @@ int bufferevent_flush(struct bufferevent *bufev,
     short iotype,
     enum bufferevent_flush_mode mode);
 
+/**
+   Flags for bufferevent_trigger(_event) that modify when and how to trigger
+   the callback.
+*/
+enum bufferevent_trigger_options {
+	/** trigger the callback regardless of the watermarks */
+	BEV_TRIG_IGNORE_WATERMARKS = (1<<0),
+
+	/** defer even if the callbacks are not */
+	BEV_TRIG_DEFER_CALLBACKS = (1<<1),
+};
+
+/**
+   Triggers bufferevent data callbacks.
+
+   The function will honor watermarks unless options contain
+   BEV_TRIG_IGNORE_WATERMARKS. If the options contain BEV_OPT_DEFER_CALLBACKS,
+   the callbacks are deferred.
+
+   @param bufev the bufferevent object
+   @param iotype either EV_READ or EV_WRITE or both.
+   @param options
+ */
+void bufferevent_trigger(struct bufferevent *bufev, short iotype,
+    int options);
+
 /**
    @name Filtering support