from trunk:

Patch from Scott Lamb: Implement event_{base_}loopbreak.  Includes documentation and tests.  From sf.net Feature Request 1826546.


svn:r584

ChangeLog

@@ -10,6 +10,7 @@ Changes in current version:
  o small improvements to evhttp documentation
  o always generate Date and Content-Length headers for HTTP/1.1 replies
  o set the correct event base for HTTP close events
+ o New function, event_{base_}loopbreak.  Like event_loopexit, it makes an event loop stop executing and return.  Unlike event_loopexit, it keeps subsequent pending events from getting executed.  Patch from Scott Lamb
 
 
 Changes in 1.4.0-beta:

event-internal.h

@@ -54,6 +54,7 @@ struct event_base {
 	int event_count_active;	/* counts number of active events */
 
 	int event_gotterm;		/* Set to terminate loop */
+	int event_break;		/* Set to terminate loop immediately */
 
 	/* active event management */
 	struct event_list **activequeues;

event.3

@@ -34,10 +34,12 @@
 .Nm event_dispatch ,
 .Nm event_loop ,
 .Nm event_loopexit ,
+.Nm event_loopbreak ,
 .Nm event_set ,
 .Nm event_base_dispatch ,
 .Nm event_base_loop ,
 .Nm event_base_loopexit ,
+.Nm event_base_loopbreak ,
 .Nm event_base_set ,
 .Nm event_base_free ,
 .Nm event_add ,
@@ -93,6 +95,8 @@
 .Fn "event_loop" "int flags"
 .Ft int
 .Fn "event_loopexit" "struct timeval *tv"
+.Ft int
+.Fn "event_loopbreak" "void"
 .Ft void
 .Fn "event_set" "struct event *ev" "int fd" "short event" "void (*fn)(int, short, void *)" "void *arg"
 .Ft int
@@ -102,6 +106,8 @@
 .Ft int
 .Fn "event_base_loopexit" "struct event_base *base" "struct timeval *tv"
 .Ft int
+.Fn "event_base_loopbreak" "struct event_base *base"
+.Ft int
 .Fn "event_base_set" "struct event_base *base" "struct event *"
 .Ft void
 .Fn "event_base_free" "struct event_base *base"
@@ -419,7 +425,16 @@ given timer expires will complete normally (handling all queued events) then
 exit without blocking for events again. Subsequent invocations of
 .Fn event_loop
 will proceed normally.
-The parameter indicates the time after which the loop should terminate.
+The
+.Nm event_loopbreak
+function exits from the event loop immediately.
+.Fn event_loop
+will abort after the next event is completed;
+.Fn event_loopbreak
+is typically invoked from this event's callback. This behavior is analogous
+to the "break;" statement. Subsequent invocations of
+.Fn event_loop
+will proceed normally.
 .Pp
 It is the responsibility of the caller to provide these functions with
 pre-allocated event structures.

event.c

@@ -358,7 +358,7 @@ event_process_active(struct event_base *base)
 			ncalls--;
 			ev->ev_ncalls = ncalls;
 			(*ev->ev_callback)((int)ev->ev_fd, ev->ev_res, ev->ev_arg);
-			if (event_gotsig)
+			if (event_gotsig || base->event_break)
 				return;
 		}
 	}
@@ -402,6 +402,25 @@ event_base_loopexit(struct event_base *event_base, struct timeval *tv)
 		    event_base, tv));
 }
 
+/* not thread safe */
+int
+event_loopbreak(void)
+{
+	return (event_base_loopbreak(current_base));
+}
+
+int
+event_base_loopbreak(struct event_base *event_base)
+{
+	if (event_base == NULL)
+		return (-1);
+
+	event_base->event_break = 1;
+	return (0);
+}
+
+
+
 /* not thread safe */
 
 int
@@ -433,6 +452,11 @@ event_base_loop(struct event_base *base, int flags)
 			break;
 		}
 
+		if (base->event_break) {
+			base->event_break = 0;
+			break;
+		}
+
 		/* You cannot use this interface for multi-threaded apps */
 		while (event_gotsig) {
 			event_gotsig = 0;

event.h

@@ -408,6 +408,35 @@ int event_loopexit(struct timeval *);
  */
 int event_base_loopexit(struct event_base *, struct timeval *);
 
+/**
+  Abort the active event_loop() immediately.
+
+  event_loop() will abort the loop after the next event is completed;
+  event_loopbreak() is typically invoked from this event's callback.
+  This behavior is analogous to the "break;" statement.
+
+  Subsequent invocations of event_loop() will proceed normally.
+
+  @return 0 if successful, or -1 if an error occurred
+  @see event_base_loopbreak(), event_loopexit()
+ */
+int event_loopbreak(void);
+
+/**
+  Abort the active event_base_loop() immediately.
+
+  event_base_loop() will abort the loop after the next event is completed;
+  event_base_loopbreak() is typically invoked from this event's callback.
+  This behavior is analogous to the "break;" statement.
+
+  Subsequent invocations of event_loop() will proceed normally.
+
+  @param eb the event_base structure returned by event_init()
+  @return 0 if successful, or -1 if an error occurred
+  @see event_base_loopexit
+ */
+int event_base_loopbreak(struct event_base *);
+
 
 /**
   Add a timer event.

test/regress.c

@@ -769,6 +769,42 @@ test_loopexit(void)
 	cleanup_test();
 }
 
+static void
+break_cb(int fd, short events, void *arg)
+{
+	test_ok = 1;
+	event_loopbreak();
+}
+
+static void
+fail_cb(int fd, short events, void *arg)
+{
+	test_ok = 0;
+}
+
+void
+test_loopbreak(void)
+{
+	struct event ev1, ev2;
+	struct timeval tv;
+
+	setup_test("Loop break: ");
+
+	tv.tv_sec = 0;
+	tv.tv_usec = 0;
+	evtimer_set(&ev1, break_cb, NULL);
+	evtimer_add(&ev1, &tv);
+	evtimer_set(&ev2, fail_cb, NULL);
+	evtimer_add(&ev2, &tv);
+
+	event_dispatch();
+
+	evtimer_del(&ev1);
+	evtimer_del(&ev2);
+
+	cleanup_test();
+}
+
 void
 test_evbuffer(void) {
 
@@ -1275,6 +1311,7 @@ main (int argc, char **argv)
 	test_immediatesignal();
 #endif
 	test_loopexit();
+	test_loopbreak();
 
 	test_multiple_events_for_same_fd();