Handle retry entirely within the fifo_read_all routine

diff --git a/x5/khatus.c b/x5/khatus.c
index 98eea2d..62b3774 100644 (file)
--- a/x5/khatus.c
+++ b/x5/khatus.c
@@ -368,13 +368,12 @@ fifo_read_one(Fifo *f, char *buf)
        /* TODO Record timestamp read */
 }
 
-int
+void
 fifo_read_all(Config *cfg, char *buf)
 {
        fd_set fds;
        int maxfd = -1;
-       int reading = 0;  /* Number of FDs with unfinished reads */
-       int ready;
+       int ready = 0;
        struct stat st;
 
        FD_ZERO(&fds);
@@ -412,41 +411,43 @@ fifo_read_all(Config *cfg, char *buf)
        debug("ready: %d\n", ready);
        assert(ready != 0);
        if (ready < 0)
+               /* TODO: Do we really want to fail here? */
                fatal("%s", strerror(errno));
-       for (Fifo *f = cfg->fifos; f; f = f->next) {
-               if (FD_ISSET(f->fd, &fds)) {
-                       reading++;
-                       debug("reading: %s\n", f->name);
-                       switch (fifo_read_one(f, buf)) {
-                       /*
-                        * ### MESSAGE LOSS ###
-                        * is introduced by closing at EOM in addition to EOF,
-                        * since there may be unread messages remaining in the
-                        * pipe. However,
-                        *
-                        * ### INTER-MESSAGE PUSHBACK ###
-                        * is also gained, since pipes block at the "open" call.
-                        *
-                        * This is an acceptable trade-off because we are a
-                        * stateless reporter of a _most-recent_ status, not a
-                        * stateful accumulator.
-                        */
-                       case END_OF_MESSAGE:
-                       case END_OF_FILE:
-                       case FAILURE:
-                               close(f->fd);
-                               f->fd = -1;
-                               reading--;
-                               break;
-                       case RETRY:
-                               break;
-                       default:
-                               assert(0);
+       while (ready) {
+               for (Fifo *f = cfg->fifos; f; f = f->next) {
+                       if (FD_ISSET(f->fd, &fds)) {
+                               debug("reading: %s\n", f->name);
+                               switch (fifo_read_one(f, buf)) {
+                               /*
+                                * ### MESSAGE LOSS ###
+                                * is introduced by closing at EOM in addition
+                                * to EOF, since there may be unread messages
+                                * remaining in the pipe. However,
+                                *
+                                * ### INTER-MESSAGE PUSHBACK ###
+                                * is also gained, since pipes block at the
+                                * "open" call.
+                                *
+                                * This is an acceptable trade-off because we
+                                * are a stateless reporter of a _most-recent_
+                                * status, not a stateful accumulator.
+                                */
+                               case END_OF_MESSAGE:
+                               case END_OF_FILE:
+                               case FAILURE:
+                                       close(f->fd);
+                                       f->fd = -1;
+                                       ready--;
+                                       break;
+                               case RETRY:
+                                       break;
+                               default:
+                                       assert(0);
+                               }
                        }
                }
        }
-       assert(reading >= 0);
-       return reading;
+       assert(ready == 0);
 }
 
 int
@@ -457,7 +458,6 @@ main(int argc, char *argv[])
        int seplen = 0;
        int prefix = 0;
        int errors = 0;
-       int reading = 0;
        char *buf;
        Config cfg0 = defaults;
        Config *cfg = &cfg0;
@@ -533,8 +533,7 @@ main(int argc, char *argv[])
                 *       fifo_read_all and desired time of next TTL check.
                 */
                /* TODO: How long to wait on IO? Max TTL? */
-               reading = fifo_read_all(cfg, buf);
-               debug("reading: %d\n", reading);
+               fifo_read_all(cfg, buf);
                if (cfg->output_to_x_root_window) {
                        if (XStoreName(display, DefaultRootWindow(display), buf) < 0)
                                fatal("XStoreName failed.\n");
@@ -546,15 +545,10 @@ main(int argc, char *argv[])
                clock_gettime(CLOCK_MONOTONIC, &t1); // FIXME: check errors
                timespecsub(&t1, &t0, &td);
                debug("td {tv_sec = %ld, tv_nsec = %ld}\n", td.tv_sec, td.tv_nsec);
-               /*
-                * Skip sleep when we aren't done reading,
-                * to avoid filling-up the pipe during sleep.
-                */
-               if (!reading && timespeccmp(&td, &ti, <)) {
+               if (timespeccmp(&td, &ti, <)) {
                        /* Pushback on data producers by refusing to read the
                         * pipe more frequently than the interval.
                         */
-                       /* FIXME: Client is never blocked after initial open. */
                        timespecsub(&ti, &td, &tc);
                        debug("snooze YES\n");
                        snooze(&tc);