ccan/io: put explicit poll flags in the plan.

Weaning off enum io_state, to allow custom ones.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

ccan/io/backend.h

@@ -77,6 +77,7 @@ struct io_conn {
 	struct io_conn *duplex;
 	struct io_timeout *timeout;
 
+	int pollflag; /* 0, POLLIN or POLLOUT */
 	enum io_state state;
 	union {
 		struct io_state_read read;

ccan/io/io.c

@@ -8,6 +8,7 @@
 #include <errno.h>
 #include <stdlib.h>
 #include <assert.h>
+#include <poll.h>
 
 void *io_loop_return;
 
@@ -56,6 +57,7 @@ struct io_conn *io_new_conn_(int fd,
 	conn->fd.next = start;
 	conn->fd.finish = finish;
 	conn->fd.finish_arg = conn->fd.next_arg = arg;
+	conn->pollflag = 0;
 	conn->state = NEXT;
 	conn->duplex = NULL;
 	conn->timeout = NULL;
@@ -84,6 +86,7 @@ struct io_conn *io_duplex_(struct io_conn *old,
 	conn->fd.next = start;
 	conn->fd.finish = finish;
 	conn->fd.finish_arg = conn->fd.next_arg = arg;
+	conn->pollflag = 0;
 	conn->state = NEXT;
 	conn->duplex = old;
 	conn->timeout = NULL;
@@ -125,6 +128,7 @@ struct io_plan *io_write_(struct io_conn *conn, const void *data, size_t len,
 	conn->u.write.len = len;
 	conn->fd.next = cb;
 	conn->fd.next_arg = arg;
+	conn->pollflag = POLLOUT;
 	return to_ioplan(WRITE);
 }
 
@@ -137,6 +141,7 @@ struct io_plan *io_read_(struct io_conn *conn, void *data, size_t len,
 	conn->u.read.len = len;
 	conn->fd.next = cb;
 	conn->fd.next_arg = arg;
+	conn->pollflag = POLLIN;
 	return to_ioplan(READ);
 }
 
@@ -149,6 +154,7 @@ struct io_plan *io_read_partial_(struct io_conn *conn, void *data, size_t *len,
 	conn->u.readpart.lenp = len;
 	conn->fd.next = cb;
 	conn->fd.next_arg = arg;
+	conn->pollflag = POLLIN;
 	return to_ioplan(READPART);
 }
 
@@ -162,11 +168,13 @@ struct io_plan *io_write_partial_(struct io_conn *conn,
 	conn->u.writepart.lenp = len;
 	conn->fd.next = cb;
 	conn->fd.next_arg = arg;
+	conn->pollflag = POLLOUT;
 	return to_ioplan(WRITEPART);
 }
 
 struct io_plan *io_idle(struct io_conn *conn)
 {
+	conn->pollflag = 0;
 	return to_ioplan(IDLE);
 }
 

ccan/io/poll.c

@@ -112,20 +112,6 @@ void del_listener(struct io_listener *l)
 	del_fd(&l->fd);
 }
 
-static int pollmask(enum io_state state)
-{
-	switch (state) {
-	case READ:
-	case READPART:
-		return POLLIN;
-	case WRITE:
-	case WRITEPART:
-		return POLLOUT;
-	default:
-		return 0;
-	}
-}
-
 void backend_set_state(struct io_conn *conn, struct io_plan *plan)
 {
 	enum io_state state = from_ioplan(plan);
@@ -134,9 +120,9 @@ void backend_set_state(struct io_conn *conn, struct io_plan *plan)
 	if (pfd->events)
 		num_waiting--;
 
-	pfd->events = pollmask(state);
+	pfd->events = conn->pollflag;
 	if (conn->duplex) {
-		int mask = pollmask(conn->duplex->state);
+		int mask = conn->duplex->pollflag;
 		/* You can't *both* read/write. */
 		assert(!mask || pfd->events != mask);
 		pfd->events |= mask;
@@ -282,7 +268,7 @@ void *io_loop(void)
 			} else if (events & (POLLIN|POLLOUT)) {
 				r--;
 				if (c->duplex) {
-					int mask = pollmask(c->duplex->state);
+					int mask = c->duplex->pollflag;
 					if (events & mask) {
 						ready(c->duplex);
 						events &= ~mask;