fixes #342 Want Surveyor/Respondent context support

fixes #360 core should nng_aio_begin before nng_aio_finish_error
fixes #361 nng_send_aio should check for NULL message
fixes #362 nni_msgq does not signal pollable on certain events

This adds support for contexts for both sides of the surveyor pattern.
Prior to this commit, the raw mode was completely broken, and there
were numerous other bugs found and fixed.  This integration includes
*much* deeper validation of this pattern.

Some changes to the core and other patterns have been made, where it
was obvioius that we could make such improvements.  (The obviousness
stemming from the fact that RESPONDENT in particular is very closely
derived from REP.)

1 files changed, 24 insertions, 4 deletions

diff --git a/src/nng.c b/src/nng.c
index 9eb33f50..fb374dde 100644
--- a/src/nng.c
+++ b/src/nng.c
@@ -198,7 +198,9 @@ nng_recv_aio(nng_socket sid, nng_aio *aio)
 	int       rv;
 
 	if ((rv = nni_sock_find(&sock, sid)) != 0) {
-		nni_aio_finish_error(aio, rv);
+		if (nni_aio_begin(aio) == 0) {
+			nni_aio_finish_error(aio, rv);
+		}
 		return;
 	}
 	nni_sock_recv(sock, aio);
@@ -211,8 +213,16 @@ nng_send_aio(nng_socket sid, nng_aio *aio)
 	nni_sock *sock;
 	int       rv;
 
+	if (nni_aio_get_msg(aio) == NULL) {
+		if (nni_aio_begin(aio) == 0) {
+			nni_aio_finish_error(aio, NNG_EINVAL);
+		}
+		return;
+	}
 	if ((rv = nni_sock_find(&sock, sid)) != 0) {
-		nni_aio_finish_error(aio, rv);
+		if (nni_aio_begin(aio) == 0) {
+			nni_aio_finish_error(aio, rv);
+		}
 		return;
 	}
 	nni_sock_send(sock, aio);
@@ -260,7 +270,9 @@ nng_ctx_recv(nng_ctx cid, nng_aio *aio)
 	nni_ctx *ctx;
 
 	if ((rv = nni_ctx_find(&ctx, cid, false)) != 0) {
-		nni_aio_finish_error(aio, rv);
+		if (nni_aio_begin(aio) == 0) {
+			nni_aio_finish_error(aio, rv);
+		}
 		return;
 	}
 	nni_ctx_recv(ctx, aio);
@@ -273,8 +285,16 @@ nng_ctx_send(nng_ctx cid, nng_aio *aio)
 	int      rv;
 	nni_ctx *ctx;
 
+	if (nni_aio_get_msg(aio) == NULL) {
+		if (nni_aio_begin(aio) == 0) {
+			nni_aio_finish_error(aio, NNG_EINVAL);
+		}
+		return;
+	}
 	if ((rv = nni_ctx_find(&ctx, cid, false)) != 0) {
-		nni_aio_finish_error(aio, rv);
+		if (nni_aio_begin(aio) == 0) {
+			nni_aio_finish_error(aio, rv);
+		}
 		return;
 	}
 	nni_ctx_send(ctx, aio);