fixes #375 integer types are error prone

This change converts the various integer types like nng_socket
in the public API to opaque structures that are passed by value.
Basically we just wrap the integer ID.  This "hack" give us strong
type checks by the compiler (yay!), at the expense of not being able
to directly use these as numbers (so comparisions for example don't
work, and neither does initialization to zero using the normal
method.

Comparison of disassembly output shows that at least with the optimizer
enabled there is no difference in the compiler output between using
a structure or an integral value.

1 files changed, 62 insertions, 33 deletions

diff --git a/src/compat/nanomsg/nn.c b/src/compat/nanomsg/nn.c
index e99c0ff3..0eb97298 100644
--- a/src/compat/nanomsg/nn.c
+++ b/src/compat/nanomsg/nn.c
@@ -221,15 +221,18 @@ nn_socket(int domain, int protocol)
 		return (-1);
 	}
 
-	return ((int) sock);
+	return ((int) sock.id);
 }
 
 int
 nn_close(int s)
 {
-	int rv;
+	int        rv;
+	nng_socket sid;
+
+	sid.id = (uint32_t) s;
 
-	if ((rv = nng_close((nng_socket) s)) != 0) {
+	if ((rv = nng_close(sid)) != 0) {
 		nn_seterror(rv);
 		return (-1);
 	}
@@ -241,12 +244,14 @@ nn_bind(int s, const char *addr)
 {
 	int          rv;
 	nng_listener l;
+	nng_socket   sid;
 
-	if ((rv = nng_listen((nng_socket) s, addr, &l, 0)) != 0) {
+	sid.id = (uint32_t) s;
+	if ((rv = nng_listen(sid, addr, &l, 0)) != 0) {
 		nn_seterror(rv);
 		return (-1);
 	}
-	return ((int) l);
+	return ((int) l.id);
 }
 
 int
@@ -254,13 +259,14 @@ nn_connect(int s, const char *addr)
 {
 	int        rv;
 	nng_dialer d;
+	nng_socket sid;
 
-	if ((rv = nng_dial((nng_socket) s, addr, &d, NNG_FLAG_NONBLOCK)) !=
-	    0) {
+	sid.id = (uint32_t) s;
+	if ((rv = nng_dial(sid, addr, &d, NNG_FLAG_NONBLOCK)) != 0) {
 		nn_seterror(rv);
 		return (-1);
 	}
-	return ((int) d);
+	return ((int) d.id);
 }
 
 int
@@ -268,6 +274,8 @@ nn_shutdown(int s, int ep)
 {
 	int rv;
 	(void) s; // Unused
+	nng_dialer   d;
+	nng_listener l;
 
 	// Socket is wired into the endpoint... so passing a bad endpoint
 	// ID can result in affecting the wrong socket.  But this requires
@@ -276,8 +284,9 @@ nn_shutdown(int s, int ep)
 	// Note that listeners and dialers share the same namespace
 	// in the core, so we can close either one this way.
 
-	if (((rv = nng_dialer_close((nng_dialer) ep)) != 0) &&
-	    ((rv = nng_listener_close((nng_listener) ep)) != 0)) {
+	d.id = l.id = (uint32_t) ep;
+	if (((rv = nng_dialer_close(d)) != 0) &&
+	    ((rv = nng_listener_close(l)) != 0)) {
 		nn_seterror(rv);
 		return (-1);
 	}
@@ -405,10 +414,11 @@ nn_recv(int s, void *buf, size_t len, int flags)
 int
 nn_recvmsg(int s, struct nn_msghdr *mh, int flags)
 {
-	int      rv;
-	nng_msg *msg;
-	size_t   len;
-	int      keep = 0;
+	int        rv;
+	nng_msg *  msg;
+	size_t     len;
+	int        keep = 0;
+	nng_socket sid;
 
 	if ((flags = nn_flags(flags)) == -1) {
 		return (-1);
@@ -422,7 +432,8 @@ nn_recvmsg(int s, struct nn_msghdr *mh, int flags)
 		return (-1);
 	}
 
-	if ((rv = nng_recvmsg((nng_socket) s, &msg, flags)) != 0) {
+	sid.id = (uint32_t) s;
+	if ((rv = nng_recvmsg(sid, &msg, flags)) != 0) {
 		nn_seterror(rv);
 		return (-1);
 	}
@@ -523,12 +534,15 @@ nn_recvmsg(int s, struct nn_msghdr *mh, int flags)
 int
 nn_sendmsg(int s, const struct nn_msghdr *mh, int flags)
 {
-	nng_msg *msg  = NULL;
-	nng_msg *cmsg = NULL;
-	char *   cdata;
-	int      keep = 0;
-	size_t   sz;
-	int      rv;
+	nng_msg *  msg  = NULL;
+	nng_msg *  cmsg = NULL;
+	nng_socket sid;
+	char *     cdata;
+	int        keep = 0;
+	size_t     sz;
+	int        rv;
+
+	sid.id = (uint32_t) s;
 
 	if ((flags = nn_flags(flags)) == -1) {
 		return (-1);
@@ -629,7 +643,7 @@ nn_sendmsg(int s, const struct nn_msghdr *mh, int flags)
 	}
 
 	sz = nng_msg_len(msg);
-	if ((rv = nng_sendmsg((nng_socket) s, msg, flags)) != 0) {
+	if ((rv = nng_sendmsg(sid, msg, flags)) != 0) {
 		if (!keep) {
 			nng_msg_free(msg);
 		}
@@ -901,7 +915,10 @@ nn_getsockopt(int s, int nnlevel, int nnopt, void *valp, size_t *szp)
 {
 	const char *name                         = NULL;
 	int (*get)(nng_socket, void *, size_t *) = NULL;
-	int rv;
+	int        rv;
+	nng_socket sid;
+
+	sid.id = (uint32_t) s;
 
 	for (unsigned i = 0; i < sizeof(options) / sizeof(options[0]); i++) {
 		if ((options[i].nnlevel == nnlevel) &&
@@ -913,7 +930,7 @@ nn_getsockopt(int s, int nnlevel, int nnopt, void *valp, size_t *szp)
 	}
 
 	if (get != NULL) {
-		return (get((nng_socket) s, valp, szp));
+		return (get(sid, valp, szp));
 	}
 
 	if (name == NULL) {
@@ -921,7 +938,7 @@ nn_getsockopt(int s, int nnlevel, int nnopt, void *valp, size_t *szp)
 		return (-1);
 	}
 
-	if ((rv = nng_getopt((nng_socket) s, name, valp, szp)) != 0) {
+	if ((rv = nng_getopt(sid, name, valp, szp)) != 0) {
 		nn_seterror(rv);
 		return (-1);
 	}
@@ -932,10 +949,13 @@ nn_getsockopt(int s, int nnlevel, int nnopt, void *valp, size_t *szp)
 int
 nn_setsockopt(int s, int nnlevel, int nnopt, const void *valp, size_t sz)
 {
+	nng_socket  sid;
 	const char *name                             = NULL;
 	int (*set)(nng_socket, const void *, size_t) = NULL;
 	int rv;
 
+	sid.id = (uint32_t) s;
+
 	for (unsigned i = 0; i < sizeof(options) / sizeof(options[0]); i++) {
 		if ((options[i].nnlevel == nnlevel) &&
 		    (options[i].nnopt == nnopt)) {
@@ -947,7 +967,7 @@ nn_setsockopt(int s, int nnlevel, int nnopt, const void *valp, size_t sz)
 	}
 
 	if (set != NULL) {
-		return (set((nng_socket) s, valp, sz));
+		return (set(sid, valp, sz));
 	}
 
 	if (name == NULL) {
@@ -955,7 +975,7 @@ nn_setsockopt(int s, int nnlevel, int nnopt, const void *valp, size_t sz)
 		return (-1);
 	}
 
-	if ((rv = nng_setopt((nng_socket) s, name, valp, sz)) != 0) {
+	if ((rv = nng_setopt(sid, name, valp, sz)) != 0) {
 		nn_seterror(rv);
 		return (-1);
 	}
@@ -996,9 +1016,14 @@ nn_cmsg_next(struct nn_msghdr *mh, struct nn_cmsghdr *first)
 int
 nn_device(int s1, int s2)
 {
-	int rv;
+	int        rv;
+	nng_socket sid1;
+	nng_socket sid2;
+
+	sid1.id = (uint32_t) s1;
+	sid2.id = (uint32_t) s2;
 
-	rv = nng_device((nng_socket) s1, (nng_socket) s2);
+	rv = nng_device(sid1, sid2);
 	// rv must always be nonzero
 	nn_seterror(rv);
 	return (-1);
@@ -1041,8 +1066,10 @@ nn_poll(struct nn_pollfd *fds, int nfds, int timeout)
 	for (int i = 0; i < nfds; i++) {
 		int fd;
 		if (fds[i].events & NN_POLLIN) {
-			if ((rv = nng_getopt_int((nng_socket) fds[i].fd,
-			         NNG_OPT_RECVFD, &fd)) != 0) {
+			nng_socket s;
+			s.id = fds[i].fd;
+			if ((rv = nng_getopt_int(s, NNG_OPT_RECVFD, &fd)) !=
+			    0) {
 				nn_seterror(rv);
 				NNI_FREE_STRUCTS(pfd, nfds * 2);
 				return (-1);
@@ -1056,8 +1083,10 @@ nn_poll(struct nn_pollfd *fds, int nfds, int timeout)
 			npfd++;
 		}
 		if (fds[i].events & NN_POLLOUT) {
-			if ((rv = nng_getopt_int((nng_socket) fds[i].fd,
-			         NNG_OPT_SENDFD, &fd)) != 0) {
+			nng_socket s;
+			s.id = fds[i].fd;
+			if ((rv = nng_getopt_int(s, NNG_OPT_SENDFD, &fd)) !=
+			    0) {
 				nn_seterror(rv);
 				NNI_FREE_STRUCTS(pfd, nfds * 2);
 				return (-1);