eventloop: clarify post_dispatch_check()
This *technically* changes the semantics of the return value of the source callbacks.
Previously you could return a negative number from a source callback and it would prevent
*other* source callbacks from triggering a subsequent recheck.
Doing that seems like such a bad idea it's not worth supporting.
v2: Log this case if it is hit, so we don't silently change behaviour.
Signed-off-by: Christopher James Halse Rogers <christopher.halse.rogers@canonical.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
diff --git a/src/event-loop.c b/src/event-loop.c
index 49e48bf..eb2dce6 100644
--- a/src/event-loop.c
+++ b/src/event-loop.c
@@ -29,6 +29,7 @@
#include <signal.h>
#include <stdlib.h>
#include <stdint.h>
+#include <stdbool.h>
#include <string.h>
#include <fcntl.h>
#include <sys/socket.h>
@@ -559,19 +560,26 @@
free(loop);
}
-static int
+static bool
post_dispatch_check(struct wl_event_loop *loop)
{
struct epoll_event ep;
struct wl_event_source *source, *next;
- int n;
+ bool needs_recheck = false;
ep.events = 0;
- n = 0;
- wl_list_for_each_safe(source, next, &loop->check_list, link)
- n += source->interface->dispatch(source, &ep);
+ wl_list_for_each_safe(source, next, &loop->check_list, link) {
+ int dispatch_result;
- return n;
+ dispatch_result = source->interface->dispatch(source, &ep);
+ if (dispatch_result < 0) {
+ wl_log("Source dispatch function returned negative value!");
+ wl_log("This would previously accidentally suppress a follow-up dispatch");
+ }
+ needs_recheck |= dispatch_result != 0;
+ }
+
+ return needs_recheck;
}
/** Dispatch the idle sources
@@ -619,7 +627,7 @@
{
struct epoll_event ep[32];
struct wl_event_source *source;
- int i, count, n;
+ int i, count;
wl_event_loop_dispatch_idle(loop);
@@ -637,9 +645,7 @@
wl_event_loop_dispatch_idle(loop);
- do {
- n = post_dispatch_check(loop);
- } while (n > 0);
+ while (post_dispatch_check(loop));
return 0;
}
