ccan/io: generic init function for listening connections.

Instead of assuming they want a connection made from the new fd, hand
the fd to a callback.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

ccan/io/backend.h

@@ -15,9 +15,8 @@ struct io_listener {
 	struct fd fd;
 
 	/* These are for connections we create. */
-	struct io_plan (*next)(struct io_conn *, void *arg);
-	void (*finish)(struct io_conn *, void *arg);
-	void *conn_arg;
+	void (*init)(int fd, void *arg);
+	void *arg;
 };
 
 struct io_timeout {

ccan/io/io.c

@@ -13,9 +13,7 @@
 void *io_loop_return;
 
 struct io_listener *io_new_listener_(int fd,
-				     struct io_plan (*start)(struct io_conn *,
-							     void *arg),
-				     void (*finish)(struct io_conn *, void *),
+				     void (*init)(int fd, void *arg),
 				     void *arg)
 {
 	struct io_listener *l = malloc(sizeof(*l));
@@ -25,9 +23,8 @@ struct io_listener *io_new_listener_(int fd,
 
 	l->fd.listener = true;
 	l->fd.fd = fd;
-	l->next = start;
-	l->finish = finish;
-	l->conn_arg = arg;
+	l->init = init;
+	l->arg = arg;
 	if (!add_listener(l)) {
 		free(l);
 		return NULL;

ccan/io/io.h

@@ -93,28 +93,21 @@ struct io_conn *io_new_conn_(int fd,
 /**
  * io_new_listener - create a new accepting listener.
  * @fd: the file descriptor.
- * @start: the first function to call on new connections.
- * @finish: the function to call when the connection is closed or fails.
- * @arg: the argument to both @start and @finish.
+ * @init: the function to call for a new connection
+ * @arg: the argument to @init.
  *
- * When @fd becomes readable, we accept() and turn that fd into a new
- * connection.
+ * When @fd becomes readable, we accept() and pass that fd to init().
  *
  * Returns NULL on error (and sets errno).
  */
-#define io_new_listener(fd, start, finish, arg)				\
+#define io_new_listener(fd, init, arg)					\
 	io_new_listener_((fd),						\
-			 typesafe_cb_preargs(struct io_plan, void *,	\
-					     (start), (arg),		\
-					     struct io_conn *),		\
-			 typesafe_cb_preargs(void, void *, (finish),	\
-					     (arg), struct io_conn *),	\
+			 typesafe_cb_preargs(void, void *,		\
+					     (init), (arg),		\
+					     int fd),			\
 			 (arg))
 struct io_listener *io_new_listener_(int fd,
-				     struct io_plan (*start)(struct io_conn *,
-							      void *arg),
-				     void (*finish)(struct io_conn *,
-						    void *arg),
+				     void (*init)(int fd, void *arg),
 				     void *arg);
 
 /**

ccan/io/poll.c

@@ -144,17 +144,12 @@ void backend_wakeup(struct io_conn *conn)
 
 static void accept_conn(struct io_listener *l)
 {
-	struct io_conn *c;
 	int fd = accept(l->fd.fd, NULL, NULL);
 
 	/* FIXME: What to do here? */
 	if (fd < 0)
 		return;
-	c = io_new_conn(fd, l->next, l->finish, l->conn_arg);
-	if (!c) {
-		close(fd);
-		return;
-	}
+	l->init(fd, l->arg);
 }
 
 /* It's OK to miss some, as long as we make progress. */

ccan/io/test/run-01-start-finish.c

@@ -20,6 +20,12 @@ static void finish_ok(struct io_conn *conn, int *state)
 	io_break(state + 1, NULL, NULL);
 }
 
+static void init_conn(int fd, int *state)
+{
+	if (!io_new_conn(fd, start_ok, finish_ok, state))
+		abort();
+}
+
 static int make_listen_fd(const char *port, struct addrinfo **info)
 {
 	int fd, on = 1;
@@ -63,7 +69,7 @@ int main(void)
 	plan_tests(9);
 	fd = make_listen_fd("65001", &addrinfo);
 	ok1(fd >= 0);
-	l = io_new_listener(fd, start_ok, finish_ok, &state);
+	l = io_new_listener(fd, init_conn, &state);
 	ok1(l);
 	fflush(stdout);
 	if (!fork()) {

ccan/io/test/run-02-read.c

@@ -25,6 +25,12 @@ static void finish_ok(struct io_conn *conn, struct data *d)
 	io_break(d, NULL, NULL);
 }
 
+static void init_conn(int fd, struct data *d)
+{
+	if (!io_new_conn(fd, start_ok, finish_ok, d))
+		abort();
+}
+
 static int make_listen_fd(const char *port, struct addrinfo **info)
 {
 	int fd, on = 1;
@@ -69,7 +75,7 @@ int main(void)
 	d->state = 0;
 	fd = make_listen_fd("65002", &addrinfo);
 	ok1(fd >= 0);
-	l = io_new_listener(fd, start_ok, finish_ok, d);
+	l = io_new_listener(fd, init_conn, d);
 	ok1(l);
 	fflush(stdout);
 	if (!fork()) {

ccan/io/test/run-03-readpartial.c

@@ -27,6 +27,12 @@ static void finish_ok(struct io_conn *conn, struct data *d)
 	io_break(d, NULL, NULL);
 }
 
+static void init_conn(int fd, struct data *d)
+{
+	if (!io_new_conn(fd, start_ok, finish_ok, d))
+		abort();
+}
+
 static int make_listen_fd(const char *port, struct addrinfo **info)
 {
 	int fd, on = 1;
@@ -89,7 +95,7 @@ int main(void)
 	d->state = 0;
 	fd = make_listen_fd("65003", &addrinfo);
 	ok1(fd >= 0);
-	l = io_new_listener(fd, start_ok, finish_ok, d);
+	l = io_new_listener(fd, init_conn, d);
 	ok1(l);
 	fflush(stdout);
 	if (!fork()) {

ccan/io/test/run-04-writepartial.c

@@ -26,6 +26,12 @@ static void finish_ok(struct io_conn *conn, struct data *d)
 	io_break(d, NULL, NULL);
 }
 
+static void init_conn(int fd, struct data *d)
+{
+	if (!io_new_conn(fd, start_ok, finish_ok, d))
+		abort();
+}
+
 static int make_listen_fd(const char *port, struct addrinfo **info)
 {
 	int fd, on = 1;
@@ -91,7 +97,7 @@ int main(void)
 	memset(d->buf, 'a', d->bytes);
 	fd = make_listen_fd("65004", &addrinfo);
 	ok1(fd >= 0);
-	l = io_new_listener(fd, start_ok, finish_ok, d);
+	l = io_new_listener(fd, init_conn, d);
 	ok1(l);
 	fflush(stdout);
 	if (!fork()) {

ccan/io/test/run-05-write.c

@@ -26,6 +26,12 @@ static void finish_ok(struct io_conn *conn, struct data *d)
 	io_break(d, NULL, NULL);
 }
 
+static void init_conn(int fd, struct data *d)
+{
+	if (!io_new_conn(fd, start_ok, finish_ok, d))
+		abort();
+}
+
 static int make_listen_fd(const char *port, struct addrinfo **info)
 {
 	int fd, on = 1;
@@ -94,7 +100,7 @@ int main(void)
 	memset(d->buf, 'a', d->bytes);
 	fd = make_listen_fd("65005", &addrinfo);
 	ok1(fd >= 0);
-	l = io_new_listener(fd, start_ok, finish_ok, d);
+	l = io_new_listener(fd, init_conn, d);
 	ok1(l);
 	fflush(stdout);
 	if (!fork()) {

ccan/io/test/run-06-idle.c

@@ -61,6 +61,12 @@ static void finish_idle(struct io_conn *conn, struct data *d)
 	io_break(d, NULL, NULL);
 }
 
+static void init_conn(int fd, struct data *d)
+{
+	if (!io_new_conn(fd, start_idle, finish_idle, d))
+		abort();
+}
+
 static int make_listen_fd(const char *port, struct addrinfo **info)
 {
 	int fd, on = 1;
@@ -105,7 +111,7 @@ int main(void)
 	d->state = 0;
 	fd = make_listen_fd("65006", &addrinfo);
 	ok1(fd >= 0);
-	l = io_new_listener(fd, start_idle, finish_idle, d);
+	l = io_new_listener(fd, init_conn, d);
 	ok1(l);
 	fflush(stdout);
 	if (!fork()) {

ccan/io/test/run-07-break.c

@@ -31,6 +31,12 @@ static void finish_ok(struct io_conn *conn, struct data *d)
 	d->state++;
 }
 
+static void init_conn(int fd, struct data *d)
+{
+	if (!io_new_conn(fd, start_break, finish_ok, d))
+		abort();
+}
+
 static int make_listen_fd(const char *port, struct addrinfo **info)
 {
 	int fd, on = 1;
@@ -75,7 +81,7 @@ int main(void)
 	d->state = 0;
 	fd = make_listen_fd("65007", &addrinfo);
 	ok1(fd >= 0);
-	l = io_new_listener(fd, start_break, finish_ok, d);
+	l = io_new_listener(fd, init_conn, d);
 	ok1(l);
 	fflush(stdout);
 	if (!fork()) {

ccan/io/test/run-12-bidir.c

@@ -36,6 +36,12 @@ static struct io_plan start_ok(struct io_conn *conn, struct data *d)
 	return io_read(d->buf, sizeof(d->buf), io_close, d);
 }
 
+static void init_conn(int fd, struct data *d)
+{
+	if (!io_new_conn(fd, start_ok, finish_ok, d))
+		abort();
+}
+
 static int make_listen_fd(const char *port, struct addrinfo **info)
 {
 	int fd, on = 1;
@@ -79,7 +85,7 @@ int main(void)
 	d->state = 0;
 	fd = make_listen_fd("65012", &addrinfo);
 	ok1(fd >= 0);
-	d->l = io_new_listener(fd, start_ok, finish_ok, d);
+	d->l = io_new_listener(fd, init_conn, d);
 	ok1(d->l);
 	fflush(stdout);
 	if (!fork()) {

ccan/io/test/run-15-timeout.c

@@ -45,6 +45,12 @@ static void finish_ok(struct io_conn *conn, struct data *d)
 	io_break(d, NULL, NULL);
 }
 
+static void init_conn(int fd, struct data *d)
+{
+	if (!io_new_conn(fd, start_ok, finish_ok, d))
+		abort();
+}
+
 static int make_listen_fd(const char *port, struct addrinfo **info)
 {
 	int fd, on = 1;
@@ -91,7 +97,7 @@ int main(void)
 	d->timeout_usec = 100000;
 	fd = make_listen_fd("65002", &addrinfo);
 	ok1(fd >= 0);
-	l = io_new_listener(fd, start_ok, finish_ok, d);
+	l = io_new_listener(fd, init_conn, d);
 	ok1(l);
 	fflush(stdout);