src/event.c: introduce ADD_POLLFD

Abstract away the fiddly fd array handling so that it is harder to
make mistakes.  We are going to want to add more fds.

No functional change in this patch.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/src/event.c b/src/event.c
index 433a4d0..04ba26b 100644 (file)
--- a/src/event.c
+++ b/src/event.c
@@ -304,29 +304,35 @@ void adns_processtimeouts(adns_state ads, const struct timeval *now) {
 
 int adns__pollfds(adns_state ads, struct pollfd pollfds_buf[MAX_POLLFDS]) {
   /* Returns the number of entries filled in.  Always zeroes revents. */
+  int nwanted=0;
+#define ADD_POLLFD(wantfd, wantevents) do{     \
+    pollfds_buf[nwanted].fd= (wantfd);         \
+    pollfds_buf[nwanted].events= (wantevents); \
+    pollfds_buf[nwanted].revents= 0;           \
+    nwanted++;                                 \
+  }while(0)
 
   assert(MAX_POLLFDS==2);
 
-  pollfds_buf[0].fd= ads->udpsocket;
-  pollfds_buf[0].events= POLLIN;
-  pollfds_buf[0].revents= 0;
+  ADD_POLLFD(ads->udpsocket, POLLIN);
 
   switch (ads->tcpstate) {
   case server_disconnected:
   case server_broken:
-    return 1;
+    break;
   case server_connecting:
-    pollfds_buf[1].events= POLLOUT;
+    ADD_POLLFD(ads->tcpsocket, POLLOUT);
     break;
   case server_ok:
-    pollfds_buf[1].events=
-      ads->tcpsend.used ? POLLIN|POLLOUT|POLLPRI : POLLIN|POLLPRI;
+    ADD_POLLFD(ads->tcpsocket,
+              ads->tcpsend.used ? POLLIN|POLLOUT|POLLPRI : POLLIN|POLLPRI);
     break;
   default:
     abort();
   }
-  pollfds_buf[1].fd= ads->tcpsocket;
-  return 2;
+  assert(nwanted<=MAX_POLLFDS);
+#undef ADD_POLLFD
+  return nwanted;
 }
 
 int adns_processreadable(adns_state ads, int fd, const struct timeval *now) {