ccan/io: make union more generic.

I really wanted an array of bytes in there, so make it more flexible.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

ccan/io/io.c

@@ -50,7 +50,7 @@ struct io_plan io_debug(struct io_plan plan)
 		if (!ready->plan.next) {
 			/* Call finish function immediately. */
 			if (ready->finish) {
-				errno = ready->plan.u.close.saved_errno;
+				errno = ready->plan.u1.s;
 				ready->finish(ready, ready->finish_arg);
 				ready->finish = NULL;
 			}
@@ -227,13 +227,13 @@ bool io_timeout_(struct io_conn *conn, struct timespec ts,
 /* Returns true if we're finished. */
 static int do_write(int fd, struct io_plan *plan)
 {
-	ssize_t ret = write(fd, plan->u.write.buf, plan->u.write.len);
+	ssize_t ret = write(fd, plan->u1.cp, plan->u2.s);
 	if (ret < 0)
 		return io_debug_io(-1);
 
-	plan->u.write.buf += ret;
-	plan->u.write.len -= ret;
-	return io_debug_io(plan->u.write.len == 0);
+	plan->u1.cp += ret;
+	plan->u2.s -= ret;
+	return io_debug_io(plan->u2.s == 0);
 }
 
 /* Queue some data to be written. */
@@ -244,8 +244,8 @@ struct io_plan io_write_(const void *data, size_t len,
 	struct io_plan plan;
 
 	assert(cb);
-	plan.u.write.buf = data;
-	plan.u.write.len = len;
+	plan.u1.const_vp = data;
+	plan.u2.s = len;
 	plan.io = do_write;
 	plan.next = cb;
 	plan.next_arg = arg;
@@ -256,13 +256,13 @@ struct io_plan io_write_(const void *data, size_t len,
 
 static int do_read(int fd, struct io_plan *plan)
 {
-	ssize_t ret = read(fd, plan->u.read.buf, plan->u.read.len);
+	ssize_t ret = read(fd, plan->u1.cp, plan->u2.s);
 	if (ret <= 0)
 		return io_debug_io(-1);
 
-	plan->u.read.buf += ret;
-	plan->u.read.len -= ret;
-	return io_debug_io(plan->u.read.len == 0);
+	plan->u1.cp += ret;
+	plan->u2.s -= ret;
+	return io_debug_io(plan->u2.s == 0);
 }
 
 /* Queue a request to read into a buffer. */
@@ -273,8 +273,8 @@ struct io_plan io_read_(void *data, size_t len,
 	struct io_plan plan;
 
 	assert(cb);
-	plan.u.read.buf = data;
-	plan.u.read.len = len;
+	plan.u1.cp = data;
+	plan.u2.s = len;
 	plan.io = do_read;
 	plan.next = cb;
 	plan.next_arg = arg;
@@ -285,11 +285,11 @@ struct io_plan io_read_(void *data, size_t len,
 
 static int do_read_partial(int fd, struct io_plan *plan)
 {
-	ssize_t ret = read(fd, plan->u.readpart.buf, *plan->u.readpart.lenp);
+	ssize_t ret = read(fd, plan->u1.cp, *(size_t *)plan->u2.vp);
 	if (ret <= 0)
 		return io_debug_io(-1);
 
-	*plan->u.readpart.lenp = ret;
+	*(size_t *)plan->u2.vp = ret;
 	return io_debug_io(1);
 }
 
@@ -301,8 +301,8 @@ struct io_plan io_read_partial_(void *data, size_t *len,
 	struct io_plan plan;
 
 	assert(cb);
-	plan.u.readpart.buf = data;
-	plan.u.readpart.lenp = len;
+	plan.u1.cp = data;
+	plan.u2.vp = len;
 	plan.io = do_read_partial;
 	plan.next = cb;
 	plan.next_arg = arg;
@@ -313,11 +313,11 @@ struct io_plan io_read_partial_(void *data, size_t *len,
 
 static int do_write_partial(int fd, struct io_plan *plan)
 {
-	ssize_t ret = write(fd, plan->u.writepart.buf, *plan->u.writepart.lenp);
+	ssize_t ret = write(fd, plan->u1.cp, *(size_t *)plan->u2.vp);
 	if (ret < 0)
 		return io_debug_io(-1);
 
-	*plan->u.writepart.lenp = ret;
+	*(size_t *)plan->u2.vp = ret;
 	return io_debug_io(1);
 }
 
@@ -329,8 +329,8 @@ struct io_plan io_write_partial_(const void *data, size_t *len,
 	struct io_plan plan;
 
 	assert(cb);
-	plan.u.writepart.buf = data;
-	plan.u.writepart.lenp = len;
+	plan.u1.const_vp = data;
+	plan.u2.vp = len;
 	plan.io = do_write_partial;
 	plan.next = cb;
 	plan.next_arg = arg;
@@ -356,7 +356,7 @@ static int do_connect(int fd, struct io_plan *plan)
 
 	if (err == 0) {
 		/* Restore blocking if it was initially. */
-		fcntl(fd, F_SETFD, plan->u.len_len.len1);
+		fcntl(fd, F_SETFD, plan->u1.s);
 		return 1;
 	}
 	return 0;
@@ -374,8 +374,8 @@ struct io_plan io_connect_(int fd, const struct addrinfo *addr,
 	plan.next_arg = arg;
 
 	/* Save old flags, set nonblock if not already. */
-	plan.u.len_len.len1 = fcntl(fd, F_GETFD);
-	fcntl(fd, F_SETFD, plan.u.len_len.len1 | O_NONBLOCK);
+	plan.u1.s = fcntl(fd, F_GETFD);
+	fcntl(fd, F_SETFD, plan.u1.s | O_NONBLOCK);
 
 	/* Immediate connect can happen. */
 	if (connect(fd, addr->ai_addr, addr->ai_addrlen) == 0) {
@@ -447,7 +447,7 @@ struct io_plan io_close_(void)
 	plan.pollflag = 0;
 	/* This means we're closing. */
 	plan.next = NULL;
-	plan.u.close.saved_errno = errno;
+	plan.u1.s = errno;
 
 	return plan;
 }

ccan/io/io_plan.h

@@ -9,7 +9,8 @@ struct io_conn;
  * @io: function to call when fd is available for @pollflag.
  * @next: function to call after @io returns true.
  * @next_arg: argument to @next.
- * @u: scratch area for I/O.
+ * @u1: scratch area for I/O.
+ * @u2: scratch area for I/O.
  *
  * When the fd is POLLIN or POLLOUT (according to @pollflag), @io is
  * called.  If it returns -1, io_close() becomed the new plan (and errno
@@ -27,38 +28,19 @@ struct io_plan {
 	void *next_arg;
 
 	union {
-		struct {
-			char *buf;
-			size_t len;
-		} read;
-		struct {
-			const char *buf;
-			size_t len;
-		} write;
-		struct {
-			char *buf;
-			size_t *lenp;
-		} readpart;
-		struct {
-			const char *buf;
-			size_t *lenp;
-		} writepart;
-		struct {
-			int saved_errno;
-		} close;
-		struct {
-			void *p;
-			size_t len;
-		} ptr_len;
-		struct {
-			void *p1;
-			void *p2;
-		} ptr_ptr;
-		struct {
-			size_t len1;
-			size_t len2;
-		} len_len;
-	} u;
+		char *cp;
+		void *vp;
+		const void *const_vp;
+		size_t s;
+		char c[sizeof(size_t)];
+	} u1;
+	union {
+		char *p;
+		void *vp;
+		const void *const_vp;
+		size_t s;
+		char c[sizeof(size_t)];
+	} u2;
 };
 
 #ifdef DEBUG

ccan/io/poll.c

@@ -175,7 +175,8 @@ bool add_duplex(struct io_conn *c)
 void backend_del_conn(struct io_conn *conn)
 {
 	if (conn->finish) {
-		errno = conn->plan.u.close.saved_errno;
+		/* Saved by io_close */
+		errno = conn->plan.u1.s;
 		conn->finish(conn, conn->finish_arg);
 	}
 	if (timeout_active(conn))

ccan/io/test/run-17-homemade-io.c

@@ -25,17 +25,17 @@ static void finish_ok(struct io_conn *conn, struct packet *pkt)
 
 static int do_read_packet(int fd, struct io_plan *plan)
 {
-	struct packet *pkt = plan->u.ptr_len.p;
+	struct packet *pkt = plan->u1.vp;
 	char *dest;
 	ssize_t ret;
 	size_t off, totlen;
 
 	/* Reading len? */
-	if (plan->u.ptr_len.len < sizeof(size_t)) {
+	if (plan->u2.s < sizeof(size_t)) {
 		ok1(pkt->state == 1);
 		pkt->state++;
 		dest = (char *)&pkt->len;
-		off = plan->u.ptr_len.len;
+		off = plan->u2.s;
 		totlen = sizeof(pkt->len);
 	} else {
 		ok1(pkt->state == 2);
@@ -46,7 +46,7 @@ static int do_read_packet(int fd, struct io_plan *plan)
 			goto fail;
 		else {
 			dest = pkt->contents;
-			off = plan->u.ptr_len.len - sizeof(pkt->len);
+			off = plan->u2.s - sizeof(pkt->len);
 			totlen = pkt->len;
 		}
 	}
@@ -55,11 +55,11 @@ static int do_read_packet(int fd, struct io_plan *plan)
 	if (ret <= 0)
 		goto fail;
 
-	plan->u.ptr_len.len += ret;
+	plan->u2.s += ret;
 
 	/* Finished? */
-	return io_debug_io(plan->u.ptr_len.len >= sizeof(pkt->len)
-			   && plan->u.ptr_len.len == pkt->len + sizeof(pkt->len));
+	return io_debug_io(plan->u2.s >= sizeof(pkt->len)
+			   && plan->u2.s == pkt->len + sizeof(pkt->len));
 
 fail:
 	free(pkt->contents);
@@ -74,8 +74,8 @@ static struct io_plan io_read_packet(struct packet *pkt,
 
 	assert(cb);
 	pkt->contents = NULL;
-	plan.u.ptr_len.p = pkt;
-	plan.u.ptr_len.len = 0;
+	plan.u1.vp = pkt;
+	plan.u2.s = 0;
 	plan.io = do_read_packet;
 	plan.next = cb;
 	plan.next_arg = arg;