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, 126 insertions, 0 deletions

diff --git a/tests/surveypoll.c b/tests/surveypoll.c
new file mode 100644
index 00000000..f97e1c22
--- /dev/null
+++ b/tests/surveypoll.c
@@ -0,0 +1,126 @@
+//
+// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2018 Capitar IT Group BV <info@capitar.com>
+//
+// This software is supplied under the terms of the MIT License, a
+// copy of which should be located in the distribution where this
+// file was obtained (LICENSE.txt).  A copy of the license may also be
+// found online at https://opensource.org/licenses/MIT.
+//
+
+#include "convey.h"
+#include "nng.h"
+#include "protocol/survey0/respond.h"
+#include "protocol/survey0/survey.h"
+#include "stubs.h"
+#include "supplemental/util/platform.h"
+
+TestMain("Survey pollable", {
+
+	atexit(nng_fini);
+
+	Convey("Given a connected survey pair", {
+		nng_socket surv;
+		nng_socket resp;
+		nng_ctx    ctx;
+
+		So(nng_surveyor0_open(&surv) == 0);
+		So(nng_respondent0_open(&resp) == 0);
+		So(nng_ctx_open(&ctx, surv) == 0);
+
+		So(nng_setopt_ms(surv, NNG_OPT_SENDTIMEO, 2000) == 0);
+		So(nng_setopt_ms(resp, NNG_OPT_SENDTIMEO, 2000) == 0);
+		So(nng_setopt_ms(surv, NNG_OPT_RECVTIMEO, 2000) == 0);
+		So(nng_setopt_ms(resp, NNG_OPT_RECVTIMEO, 2000) == 0);
+
+		Reset({
+			nng_ctx_close(ctx);
+			nng_close(surv);
+			nng_close(resp);
+		});
+		So(nng_listen(resp, "inproc://ctx1", NULL, 0) == 0);
+
+		Convey("Surveyor ctx not pollable", {
+			int fd;
+
+			So(nng_ctx_getopt_int(ctx, NNG_OPT_SENDFD, &fd) ==
+			    NNG_ENOTSUP);
+			So(nng_ctx_getopt_int(ctx, NNG_OPT_RECVFD, &fd) ==
+			    NNG_ENOTSUP);
+		});
+
+		Convey("Suveyor starts writable", {
+			int fd;
+
+			So(nng_getopt_int(surv, NNG_OPT_SENDFD, &fd) == 0);
+			So(fdready(fd) == true);
+
+			Convey("And becomes readable on connect", {
+				So(nng_dial(surv, "inproc://ctx1", NULL, 0) ==
+				    0);
+				nng_msleep(100);
+				So(fdready(fd) == true);
+
+				Convey("And stays writable", {
+					// 500 messages should force all
+					// the way to send depth.
+					int i;
+					for (i = 0; i < 500; i++) {
+						nng_msg *m;
+						if (nng_msg_alloc(&m, 0) !=
+						    0) {
+							break;
+						}
+						// Fill intermediate queues.
+						if (nng_sendmsg(surv, m,
+						        NNG_FLAG_NONBLOCK) !=
+						    0) {
+							nng_msg_free(m);
+						}
+					}
+					So(i == 500);
+					So(fdready(fd) == true);
+				});
+			});
+		});
+
+		Convey("Surveyor starts not readable", {
+			int fd;
+
+			So(nng_getopt_int(surv, NNG_OPT_RECVFD, &fd) == 0);
+			So(fdready(fd) == false);
+
+			Convey("And doesn't become readable on connect", {
+				So(nng_dial(surv, "inproc://ctx1", NULL, 0) ==
+				    0);
+				nng_msleep(100);
+				So(fdready(fd) == false);
+			});
+
+			Convey("And becomes readable on data", {
+				nng_msg *msg;
+
+				So(nng_dial(surv, "inproc://ctx1", NULL, 0) ==
+				    0);
+				nng_msleep(200);
+
+				So(nng_msg_alloc(&msg, 0) == 0);
+				So(fdready(fd) == false);
+				So(nng_msg_append(msg, "xyz", 3) == 0);
+				So(nng_sendmsg(surv, msg, 0) == 0);
+				So(nng_recvmsg(resp, &msg, 0) ==
+				    0); // recv on rep
+				So(nng_sendmsg(resp, msg, 0) ==
+				    0); // echo it back
+				nng_msleep(
+				    300); // give time for message to arrive
+				So(fdready(fd) == true);
+				Convey("Is no longer readable after recv", {
+					So(nng_recvmsg(surv, &msg, 0) == 0);
+					nng_msg_free(msg);
+					So(fdready(fd) == false);
+				});
+			});
+		});
+	});
+});