ccan/io: keep always pointers to plans, not a linked list.

[ccan] / ccan / io / io.c

diff --git a/ccan/io/io.c b/ccan/io/io.c
index 99f0f7c90fd8580f4dac211134b5ec87da544bf4..7ebd5a202d7899f356ed1963eb3c6f463ee986e2 100644 (file)
--- a/ccan/io/io.c
+++ b/ccan/io/io.c
@@ -61,10 +61,7 @@ static bool next_plan(struct io_conn *conn, struct io_plan *plan)
        if (plan == &io_conn_freed)
                return false;
 
-       /* It should have set a plan inside this conn (or duplex) */
-       assert(plan == &conn->plan[IO_IN]
-              || plan == &conn->plan[IO_OUT]
-              || plan == &conn->plan[2]);
+       assert(plan == &conn->plan[plan->dir]);
        assert(conn->plan[IO_IN].status != IO_UNSET
               || conn->plan[IO_OUT].status != IO_UNSET);
 
@@ -100,7 +97,6 @@ struct io_conn *io_new_conn_(const tal_t *ctx, int fd,
        conn->fd.fd = fd;
        conn->finish = NULL;
        conn->finish_arg = NULL;
-       list_node_init(&conn->always);
 
        if (!add_conn(conn))
                return tal_free(conn);
@@ -108,6 +104,10 @@ struct io_conn *io_new_conn_(const tal_t *ctx, int fd,
        /* Keep our I/O async. */
        io_fd_block(fd, false);
 
+       /* So we can get back from plan -> conn later */
+       conn->plan[IO_OUT].dir = IO_OUT;
+       conn->plan[IO_IN].dir = IO_IN;
+
        /* We start with out doing nothing, and in doing our init. */
        conn->plan[IO_OUT].status = IO_UNSET;
 
@@ -131,7 +131,7 @@ struct io_plan_arg *io_plan_arg(struct io_conn *conn, enum io_direction dir)
 {
        assert(conn->plan[dir].status == IO_UNSET);
 
-       conn->plan[dir].status = IO_POLLING;
+       conn->plan[dir].status = IO_POLLING_NOTSTARTED;
        return &conn->plan[dir].arg;
 }
 
@@ -144,7 +144,9 @@ static struct io_plan *set_always(struct io_conn *conn,
        struct io_plan *plan = &conn->plan[dir];
 
        plan->status = IO_ALWAYS;
-       backend_new_always(conn);
+       /* Only happens on OOM, and only with non-default tal_backend. */
+       if (!backend_new_always(plan))
+               return NULL;
        return io_set_plan(conn, dir, NULL, next, arg);
 }
 
@@ -202,8 +204,12 @@ struct io_plan *io_write_(struct io_conn *conn, const void *data, size_t len,
 static int do_read(int fd, struct io_plan_arg *arg)
 {
        ssize_t ret = read(fd, arg->u1.cp, arg->u2.s);
-       if (ret <= 0)
+       if (ret <= 0) {
+               /* Errno isn't set if we hit EOF, so set it to distinct value */
+               if (ret == 0)
+                       errno = 0;
                return -1;
+       }
 
        arg->u1.cp += ret;
        arg->u2.s -= ret;
@@ -230,8 +236,12 @@ struct io_plan *io_read_(struct io_conn *conn,
 static int do_read_partial(int fd, struct io_plan_arg *arg)
 {
        ssize_t ret = read(fd, arg->u1.cp, *(size_t *)arg->u2.vp);
-       if (ret <= 0)
+       if (ret <= 0) {
+               /* Errno isn't set if we hit EOF, so set it to distinct value */
+               if (ret == 0)
+                       errno = 0;
                return -1;
+       }
 
        *(size_t *)arg->u2.vp = ret;
        return 1;
@@ -368,7 +378,8 @@ static bool do_plan(struct io_conn *conn, struct io_plan *plan,
                    bool idle_on_epipe)
 {
        /* We shouldn't have polled for this event if this wasn't true! */
-       assert(plan->status == IO_POLLING);
+       assert(plan->status == IO_POLLING_NOTSTARTED
+              || plan->status == IO_POLLING_STARTED);
 
        switch (plan->io(conn->fd.fd, &plan->arg)) {
        case -1:
@@ -380,6 +391,7 @@ static bool do_plan(struct io_conn *conn, struct io_plan *plan,
                io_close(conn);
                return false;
        case 0:
+               plan->status = IO_POLLING_STARTED;
                return true;
        case 1:
                return next_plan(conn, plan);
@@ -399,30 +411,18 @@ void io_ready(struct io_conn *conn, int pollflags)
                /* If we're writing to a closed pipe, we need to wait for
                 * read to fail if we're duplex: we want to drain it! */
                do_plan(conn, &conn->plan[IO_OUT],
-                       conn->plan[IO_IN].status == IO_POLLING);
+                       conn->plan[IO_IN].status == IO_POLLING_NOTSTARTED
+                       || conn->plan[IO_IN].status == IO_POLLING_STARTED);
 }
 
-void io_do_always(struct io_conn *conn)
+void io_do_always(struct io_plan *plan)
 {
-       /* There's a corner case where the in next_plan wakes up the
-        * out, placing it in IO_ALWAYS and we end up processing it immediately,
-        * only to leave it in the always list.
-        *
-        * Yet we can't just process one, in case they are both supposed
-        * to be done, so grab state beforehand.
-        */
-       bool always_out = (conn->plan[IO_OUT].status == IO_ALWAYS);
+       struct io_conn *conn;
 
-       if (conn->plan[IO_IN].status == IO_ALWAYS)
-               if (!next_plan(conn, &conn->plan[IO_IN]))
-                       return;
+       assert(plan->status == IO_ALWAYS);
+       conn = container_of(plan, struct io_conn, plan[plan->dir]);
 
-       if (always_out) {
-               /* You can't *unalways* a conn (except by freeing, in which
-                * case next_plan() returned false */
-               assert(conn->plan[IO_OUT].status == IO_ALWAYS);
-               next_plan(conn, &conn->plan[IO_OUT]);
-       }
+       next_plan(conn, plan);
 }
 
 void io_do_wakeup(struct io_conn *conn, enum io_direction dir)
@@ -477,7 +477,7 @@ struct io_plan *io_duplex(struct io_conn *conn,
        assert(conn == container_of(in_plan, struct io_conn, plan[IO_IN]));
        /* in_plan must be conn->plan[IO_IN], out_plan must be [IO_OUT] */
        assert(out_plan == in_plan + 1);
-       return out_plan + 1;
+       return in_plan;
 }
 
 struct io_plan *io_halfclose(struct io_conn *conn)
@@ -509,13 +509,24 @@ struct io_plan *io_set_plan(struct io_conn *conn, enum io_direction dir,
        return plan;
 }
 
+bool io_plan_in_started(const struct io_conn *conn)
+{
+       return conn->plan[IO_IN].status == IO_POLLING_STARTED;
+}
+
+bool io_plan_out_started(const struct io_conn *conn)
+{
+       return conn->plan[IO_OUT].status == IO_POLLING_STARTED;
+}
+
 bool io_flush_sync(struct io_conn *conn)
 {
        struct io_plan *plan = &conn->plan[IO_OUT];
        bool ok;
 
        /* Not writing?  Nothing to do. */
-       if (plan->status != IO_POLLING)
+       if (plan->status != IO_POLLING_STARTED
+           && plan->status != IO_POLLING_NOTSTARTED)
                return true;
 
        /* Synchronous please. */
@@ -528,6 +539,7 @@ again:
                break;
        /* Incomplete, try again. */
        case 0:
+               plan->status = IO_POLLING_STARTED;
                goto again;
        case 1:
                ok = true;