io: io_always, and zero-length operations support.
[ccan] / ccan / io / poll.c
index f15644025cf3fdb756e2e1e20bb53935f02f7b64..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;
@@ -28,7 +29,7 @@ static void io_loop_exit(void)
                while (free_later) {
                        struct io_conn *c = free_later;
                        free_later = c->finish_arg;
-                       free(c);
+                       io_alloc.free(c);
                }
        }
 }
@@ -42,7 +43,7 @@ static void free_conn(struct io_conn *conn)
                conn->finish_arg = free_later;
                free_later = conn;
        } else
-               free(conn);
+               io_alloc.free(conn);
 }
 #else
 static void io_loop_enter(void)
@@ -53,7 +54,7 @@ static void io_loop_exit(void)
 }
 static void free_conn(struct io_conn *conn)
 {
-       free(conn);
+       io_alloc.free(conn);
 }
 #endif
 
@@ -64,11 +65,11 @@ static bool add_fd(struct fd *fd, short events)
                struct fd **newfds;
                size_t num = max_fds ? max_fds * 2 : 8;
 
-               newpollfds = realloc(pollfds, sizeof(*newpollfds) * num);
+               newpollfds = io_alloc.realloc(pollfds, sizeof(*newpollfds)*num);
                if (!newpollfds)
                        return false;
                pollfds = newpollfds;
-               newfds = realloc(fds, sizeof(*newfds) * num);
+               newfds = io_alloc.realloc(fds, sizeof(*newfds) * num);
                if (!newfds)
                        return false;
                fds = newfds;
@@ -105,10 +106,18 @@ 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. */
-               free(pollfds);
-               free(fds);
+               io_alloc.free(pollfds);
+               io_alloc.free(fds);
                pollfds = NULL;
                fds = NULL;
                max_fds = 0;
@@ -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;
 }
 
@@ -181,9 +195,10 @@ void backend_del_conn(struct io_conn *conn)
        }
        if (timeout_active(conn))
                backend_del_timeout(conn);
-       free(conn->timeout);
+       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;
 
@@ -346,7 +386,11 @@ void *do_io_loop(struct io_conn **ready)
                                                 * anything can change. */
                                                if (doing_debug())
                                                        break;
-                                               if (!(events&(POLLIN|POLLOUT)))
+
+                                               /* If no events, or it closed
+                                                * the duplex, continue. */
+                                               if (!(events&(POLLIN|POLLOUT))
+                                                   || !c->plan.next)
                                                        continue;
                                        }
                                }