io: io_always, and zero-length operations support.
[ccan] / ccan / io / poll.c
index 1b11badd642c0d87d1270d642ac63db40f9cb24e..d7b9eb56b950b5a1b4772525c86bb944b3a60c6f 100644 (file)
@@ -10,6 +10,7 @@
 #include <errno.h>
 
 static size_t num_fds = 0, max_fds = 0, num_closing = 0, num_waiting = 0;
+static bool some_always = false;
 static struct pollfd *pollfds = NULL;
 static struct fd **fds = NULL;
 static struct timers timeouts;
@@ -105,6 +106,14 @@ static void del_fd(struct fd *fd)
                fds[n] = fds[num_fds-1];
                assert(fds[n]->backend_info == num_fds-1);
                fds[n]->backend_info = n;
+               /* If that happens to be a duplex, move that too. */
+               if (!fds[n]->listener) {
+                       struct io_conn *c = (void *)fds[n];
+                       if (c->duplex) {
+                               assert(c->duplex->fd.backend_info == num_fds-1);
+                               c->duplex->fd.backend_info = n;
+                       }
+               }
        } else if (num_fds == 1) {
                /* Free everything when no more fds. */
                io_alloc.free(pollfds);
@@ -138,9 +147,9 @@ void backend_plan_changed(struct io_conn *conn)
        if (pfd->events)
                num_waiting--;
 
-       pfd->events = conn->plan.pollflag;
+       pfd->events = conn->plan.pollflag & (POLLIN|POLLOUT);
        if (conn->duplex) {
-               int mask = conn->duplex->plan.pollflag;
+               int mask = conn->duplex->plan.pollflag & (POLLIN|POLLOUT);
                /* You can't *both* read/write. */
                assert(!mask || pfd->events != mask);
                pfd->events |= mask;
@@ -153,15 +162,20 @@ void backend_plan_changed(struct io_conn *conn)
 
        if (!conn->plan.next)
                num_closing++;
+
+       if (conn->plan.pollflag == POLLALWAYS)
+               some_always = true;
 }
 
 bool add_conn(struct io_conn *c)
 {
-       if (!add_fd(&c->fd, c->plan.pollflag))
+       if (!add_fd(&c->fd, c->plan.pollflag & (POLLIN|POLLOUT)))
                return false;
        /* Immediate close is allowed. */
        if (!c->plan.next)
                num_closing++;
+       if (c->plan.pollflag == POLLALWAYS)
+               some_always = true;
        return true;
 }
 
@@ -184,6 +198,7 @@ void backend_del_conn(struct io_conn *conn)
        io_alloc.free(conn->timeout);
        if (conn->duplex) {
                /* In case fds[] pointed to the other one. */
+               assert(conn->duplex->fd.backend_info == conn->fd.backend_info);
                fds[conn->fd.backend_info] = &conn->duplex->fd;
                conn->duplex->duplex = NULL;
                conn->fd.backend_info = -1;
@@ -258,6 +273,26 @@ void backend_del_timeout(struct io_conn *conn)
        conn->timeout->conn = NULL;
 }
 
+static void handle_always(void)
+{
+       int i;
+
+       some_always = false;
+
+       for (i = 0; i < num_fds && !io_loop_return; i++) {
+               struct io_conn *c = (void *)fds[i];
+
+               if (fds[i]->listener)
+                       continue;
+
+               if (c->plan.pollflag == POLLALWAYS)
+                       io_ready(c);
+
+               if (c->duplex && c->duplex->plan.pollflag == POLLALWAYS)
+                       io_ready(c->duplex);
+       }
+}
+
 /* This is the main loop. */
 void *do_io_loop(struct io_conn **ready)
 {
@@ -308,6 +343,11 @@ void *do_io_loop(struct io_conn **ready)
                if (doing_debug() && some_timeouts)
                        continue;
 
+               if (some_always) {
+                       handle_always();
+                       continue;
+               }
+
                if (num_fds == 0)
                        break;