fixes #143 Protocols and transports should be "configurable"

This makes all the protocols and transports optional.  All
of them except ZeroTier are enabled by default, but you can
now disable them (remove from the build) with cmake options.

The test suite is modified so that tests still run as much
as they can, but skip over things caused by missing functionality
from the library (due to configuration).

Further, the constant definitions and prototypes for functions
that are specific to transports or protocols are moved into
appropriate headers, which should be included directly by
applications wishing to use these.

We have also added and improved documentation -- all of the
transports are documented, and several more man pages for
protocols have been added.  (Req/Rep and Surveyor are still
missing.)

5 files changed, 596 insertions, 0 deletions

diff --git a/src/protocol/pipeline0/CMakeLists.txt b/src/protocol/pipeline0/CMakeLists.txt
new file mode 100644
index 00000000..6153c5a7
--- /dev/null
+++ b/src/protocol/pipeline0/CMakeLists.txt
@@ -0,0 +1,23 @@
+#
+# Copyright 2017 Garrett D'Amore <garrett@damore.org>
+# Copyright 2017 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.
+#
+
+#  Pub/Sub protocol
+
+if (NNG_PROTO_PUSH0)
+    set(PUSH0_SOURCES protocol/pipeline0/push.c protocol/pipeline0/push.h)
+    install(FILES push.h DESTINATION include/nng/protocol/pipeline0)
+endif()
+
+if (NNG_PROTO_PULL0)
+    set(PULL0_SOURCES protocol/pipeline0/pull.c protocol/pipeline0/pull.h)
+    install(FILES pull.h DESTINATION include/nng/protocol/pipeline0)
+endif()
+
+set(NNG_SOURCES ${NNG_SOURCES} ${PUSH0_SOURCES} ${PULL0_SOURCES} PARENT_SCOPE)
\ No newline at end of file
diff --git a/src/protocol/pipeline0/pull.c b/src/protocol/pipeline0/pull.c
new file mode 100644
index 00000000..8c16cb17
--- /dev/null
+++ b/src/protocol/pipeline0/pull.c
@@ -0,0 +1,250 @@
+//
+// Copyright 2017 Garrett D'Amore <garrett@damore.org>
+// Copyright 2017 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 <stdlib.h>
+#include <string.h>
+
+#include "core/nng_impl.h"
+
+// Pull protocol.  The PULL protocol is the "read" side of a pipeline.
+
+#ifndef NNI_PROTO_PULL_V0
+#define NNI_PROTO_PULL_V0 NNI_PROTO(5, 1)
+#endif
+
+#ifndef NNI_PROTO_PUSH_V0
+#define NNI_PROTO_PUSH_V0 NNI_PROTO(5, 0)
+#endif
+
+typedef struct pull0_pipe pull0_pipe;
+typedef struct pull0_sock pull0_sock;
+
+static void pull0_putq_cb(void *);
+static void pull0_recv_cb(void *);
+static void pull0_putq(pull0_pipe *, nni_msg *);
+
+// pull0_sock is our per-socket protocol private structure.
+struct pull0_sock {
+	nni_msgq *urq;
+	int       raw;
+};
+
+// pull0_pipe is our per-pipe protocol private structure.
+struct pull0_pipe {
+	nni_pipe *  pipe;
+	pull0_sock *pull;
+	nni_aio *   putq_aio;
+	nni_aio *   recv_aio;
+};
+
+static int
+pull0_sock_init(void **sp, nni_sock *sock)
+{
+	pull0_sock *s;
+
+	if ((s = NNI_ALLOC_STRUCT(s)) == NULL) {
+		return (NNG_ENOMEM);
+	}
+	s->raw = 0;
+	s->urq = nni_sock_recvq(sock);
+
+	*sp = s;
+	return (0);
+}
+
+static void
+pull0_sock_fini(void *arg)
+{
+	pull0_sock *s = arg;
+
+	NNI_FREE_STRUCT(s);
+}
+
+static void
+pull0_pipe_fini(void *arg)
+{
+	pull0_pipe *p = arg;
+
+	nni_aio_fini(p->putq_aio);
+	nni_aio_fini(p->recv_aio);
+	NNI_FREE_STRUCT(p);
+}
+
+static int
+pull0_pipe_init(void **pp, nni_pipe *pipe, void *s)
+{
+	pull0_pipe *p;
+	int         rv;
+
+	if ((p = NNI_ALLOC_STRUCT(p)) == NULL) {
+		return (NNG_ENOMEM);
+	}
+	if (((rv = nni_aio_init(&p->putq_aio, pull0_putq_cb, p)) != 0) ||
+	    ((rv = nni_aio_init(&p->recv_aio, pull0_recv_cb, p)) != 0)) {
+		pull0_pipe_fini(p);
+		return (rv);
+	}
+
+	p->pipe = pipe;
+	p->pull = s;
+	*pp     = p;
+	return (0);
+}
+
+static int
+pull0_pipe_start(void *arg)
+{
+	pull0_pipe *p = arg;
+
+	// Start the pending pull...
+	nni_pipe_recv(p->pipe, p->recv_aio);
+
+	return (0);
+}
+
+static void
+pull0_pipe_stop(void *arg)
+{
+	pull0_pipe *p = arg;
+
+	nni_aio_stop(p->putq_aio);
+	nni_aio_stop(p->recv_aio);
+}
+
+static void
+pull0_recv_cb(void *arg)
+{
+	pull0_pipe *p   = arg;
+	nni_aio *   aio = p->recv_aio;
+	nni_msg *   msg;
+
+	if (nni_aio_result(aio) != 0) {
+		// Failed to get a message, probably the pipe is closed.
+		nni_pipe_stop(p->pipe);
+		return;
+	}
+
+	// Got a message... start the put to send it up to the application.
+	msg = nni_aio_get_msg(aio);
+	nni_msg_set_pipe(msg, nni_pipe_id(p->pipe));
+	nni_aio_set_msg(aio, NULL);
+	pull0_putq(p, msg);
+}
+
+static void
+pull0_putq_cb(void *arg)
+{
+	pull0_pipe *p   = arg;
+	nni_aio *   aio = p->putq_aio;
+
+	if (nni_aio_result(aio) != 0) {
+		// If we failed to put, probably NNG_ECLOSED, nothing else
+		// we can do.  Just close the pipe.
+		nni_msg_free(nni_aio_get_msg(aio));
+		nni_aio_set_msg(aio, NULL);
+		nni_pipe_stop(p->pipe);
+		return;
+	}
+
+	nni_pipe_recv(p->pipe, p->recv_aio);
+}
+
+// pull0_putq schedules a put operation to the user socket (sendup).
+static void
+pull0_putq(pull0_pipe *p, nni_msg *msg)
+{
+	pull0_sock *s = p->pull;
+
+	nni_aio_set_msg(p->putq_aio, msg);
+
+	nni_msgq_aio_put(s->urq, p->putq_aio);
+}
+
+static void
+pull0_sock_open(void *arg)
+{
+	NNI_ARG_UNUSED(arg);
+}
+
+static void
+pull0_sock_close(void *arg)
+{
+	NNI_ARG_UNUSED(arg);
+}
+
+static int
+pull0_sock_setopt_raw(void *arg, const void *buf, size_t sz)
+{
+	pull0_sock *s = arg;
+	return (nni_setopt_int(&s->raw, buf, sz, 0, 1));
+}
+
+static int
+pull0_sock_getopt_raw(void *arg, void *buf, size_t *szp)
+{
+	pull0_sock *s = arg;
+	return (nni_getopt_int(s->raw, buf, szp));
+}
+
+static void
+pull0_sock_send(void *arg, nni_aio *aio)
+{
+	nni_aio_finish_error(aio, NNG_ENOTSUP);
+}
+
+static void
+pull0_sock_recv(void *arg, nni_aio *aio)
+{
+	pull0_sock *s = arg;
+
+	nni_msgq_aio_get(s->urq, aio);
+}
+
+static nni_proto_pipe_ops pull0_pipe_ops = {
+	.pipe_init  = pull0_pipe_init,
+	.pipe_fini  = pull0_pipe_fini,
+	.pipe_start = pull0_pipe_start,
+	.pipe_stop  = pull0_pipe_stop,
+};
+
+static nni_proto_sock_option pull0_sock_options[] = {
+	{
+	    .pso_name   = NNG_OPT_RAW,
+	    .pso_getopt = pull0_sock_getopt_raw,
+	    .pso_setopt = pull0_sock_setopt_raw,
+	},
+	// terminate list
+	{ NULL, NULL, NULL },
+};
+
+static nni_proto_sock_ops pull0_sock_ops = {
+	.sock_init    = pull0_sock_init,
+	.sock_fini    = pull0_sock_fini,
+	.sock_open    = pull0_sock_open,
+	.sock_close   = pull0_sock_close,
+	.sock_send    = pull0_sock_send,
+	.sock_recv    = pull0_sock_recv,
+	.sock_options = pull0_sock_options,
+};
+
+static nni_proto pull0_proto = {
+	.proto_version  = NNI_PROTOCOL_VERSION,
+	.proto_self     = { NNI_PROTO_PULL_V0, "pull" },
+	.proto_peer     = { NNI_PROTO_PUSH_V0, "push" },
+	.proto_flags    = NNI_PROTO_FLAG_RCV,
+	.proto_pipe_ops = &pull0_pipe_ops,
+	.proto_sock_ops = &pull0_sock_ops,
+};
+
+int
+nng_pull0_open(nng_socket *sidp)
+{
+	return (nni_proto_open(sidp, &pull0_proto));
+}
diff --git a/src/protocol/pipeline0/pull.h b/src/protocol/pipeline0/pull.h
new file mode 100644
index 00000000..75bded03
--- /dev/null
+++ b/src/protocol/pipeline0/pull.h
@@ -0,0 +1,28 @@
+//
+// Copyright 2017 Garrett D'Amore <garrett@damore.org>
+// Copyright 2017 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.
+//
+
+#ifndef NNG_PROTOCOL_PIPELINE0_PULL_H
+#define NNG_PROTOCOL_PIPELINE0_PULL_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+NNG_DECL int nng_pull0_open(nng_socket *);
+
+#ifndef nng_pull_open
+#define nng_pull_open nng_pull0_open
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // NNG_PROTOCOL_PIPELINE0_PULL_H
diff --git a/src/protocol/pipeline0/push.c b/src/protocol/pipeline0/push.c
new file mode 100644
index 00000000..3dd83fe0
--- /dev/null
+++ b/src/protocol/pipeline0/push.c
@@ -0,0 +1,267 @@
+//
+// Copyright 2017 Garrett D'Amore <garrett@damore.org>
+// Copyright 2017 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 <stdlib.h>
+#include <string.h>
+
+#include "core/nng_impl.h"
+
+// Push protocol.  The PUSH protocol is the "write" side of a pipeline.
+// Push distributes fairly, or tries to, by giving messages in round-robin
+// order.
+
+#ifndef NNI_PROTO_PULL_V0
+#define NNI_PROTO_PULL_V0 NNI_PROTO(5, 1)
+#endif
+
+#ifndef NNI_PROTO_PUSH_V0
+#define NNI_PROTO_PUSH_V0 NNI_PROTO(5, 0)
+#endif
+
+typedef struct push0_pipe push0_pipe;
+typedef struct push0_sock push0_sock;
+
+static void push0_send_cb(void *);
+static void push0_recv_cb(void *);
+static void push0_getq_cb(void *);
+
+// push0_sock is our per-socket protocol private structure.
+struct push0_sock {
+	nni_msgq *uwq;
+	int       raw;
+};
+
+// push0_pipe is our per-pipe protocol private structure.
+struct push0_pipe {
+	nni_pipe *    pipe;
+	push0_sock *  push;
+	nni_list_node node;
+
+	nni_aio *aio_recv;
+	nni_aio *aio_send;
+	nni_aio *aio_getq;
+};
+
+static int
+push0_sock_init(void **sp, nni_sock *sock)
+{
+	push0_sock *s;
+
+	if ((s = NNI_ALLOC_STRUCT(s)) == NULL) {
+		return (NNG_ENOMEM);
+	}
+	s->raw = 0;
+	s->uwq = nni_sock_sendq(sock);
+	*sp    = s;
+	return (0);
+}
+
+static void
+push0_sock_fini(void *arg)
+{
+	push0_sock *s = arg;
+
+	NNI_FREE_STRUCT(s);
+}
+
+static void
+push0_sock_open(void *arg)
+{
+	NNI_ARG_UNUSED(arg);
+}
+
+static void
+push0_sock_close(void *arg)
+{
+	NNI_ARG_UNUSED(arg);
+}
+
+static void
+push0_pipe_fini(void *arg)
+{
+	push0_pipe *p = arg;
+
+	nni_aio_fini(p->aio_recv);
+	nni_aio_fini(p->aio_send);
+	nni_aio_fini(p->aio_getq);
+	NNI_FREE_STRUCT(p);
+}
+
+static int
+push0_pipe_init(void **pp, nni_pipe *pipe, void *s)
+{
+	push0_pipe *p;
+	int         rv;
+
+	if ((p = NNI_ALLOC_STRUCT(p)) == NULL) {
+		return (NNG_ENOMEM);
+	}
+	if (((rv = nni_aio_init(&p->aio_recv, push0_recv_cb, p)) != 0) ||
+	    ((rv = nni_aio_init(&p->aio_send, push0_send_cb, p)) != 0) ||
+	    ((rv = nni_aio_init(&p->aio_getq, push0_getq_cb, p)) != 0)) {
+		push0_pipe_fini(p);
+		return (rv);
+	}
+	NNI_LIST_NODE_INIT(&p->node);
+	p->pipe = pipe;
+	p->push = s;
+	*pp     = p;
+	return (0);
+}
+
+static int
+push0_pipe_start(void *arg)
+{
+	push0_pipe *p = arg;
+	push0_sock *s = p->push;
+
+	if (nni_pipe_peer(p->pipe) != NNI_PROTO_PULL_V0) {
+		return (NNG_EPROTO);
+	}
+
+	// Schedule a receiver.  This is mostly so that we can detect
+	// a closed transport pipe.
+	nni_pipe_recv(p->pipe, p->aio_recv);
+
+	// Schedule a sender.
+	nni_msgq_aio_get(s->uwq, p->aio_getq);
+
+	return (0);
+}
+
+static void
+push0_pipe_stop(void *arg)
+{
+	push0_pipe *p = arg;
+
+	nni_aio_stop(p->aio_recv);
+	nni_aio_stop(p->aio_send);
+	nni_aio_stop(p->aio_getq);
+}
+
+static void
+push0_recv_cb(void *arg)
+{
+	push0_pipe *p = arg;
+
+	// We normally expect to receive an error.  If a pipe actually
+	// sends us data, we just discard it.
+	if (nni_aio_result(p->aio_recv) != 0) {
+		nni_pipe_stop(p->pipe);
+		return;
+	}
+	nni_msg_free(nni_aio_get_msg(p->aio_recv));
+	nni_aio_set_msg(p->aio_recv, NULL);
+	nni_pipe_recv(p->pipe, p->aio_recv);
+}
+
+static void
+push0_send_cb(void *arg)
+{
+	push0_pipe *p = arg;
+	push0_sock *s = p->push;
+
+	if (nni_aio_result(p->aio_send) != 0) {
+		nni_msg_free(nni_aio_get_msg(p->aio_send));
+		nni_aio_set_msg(p->aio_send, NULL);
+		nni_pipe_stop(p->pipe);
+		return;
+	}
+
+	nni_msgq_aio_get(s->uwq, p->aio_getq);
+}
+
+static void
+push0_getq_cb(void *arg)
+{
+	push0_pipe *p   = arg;
+	nni_aio *   aio = p->aio_getq;
+
+	if (nni_aio_result(aio) != 0) {
+		// If the socket is closing, nothing else we can do.
+		nni_pipe_stop(p->pipe);
+		return;
+	}
+
+	nni_aio_set_msg(p->aio_send, nni_aio_get_msg(aio));
+	nni_aio_set_msg(aio, NULL);
+
+	nni_pipe_send(p->pipe, p->aio_send);
+}
+
+static int
+push0_sock_setopt_raw(void *arg, const void *buf, size_t sz)
+{
+	push0_sock *s = arg;
+	return (nni_setopt_int(&s->raw, buf, sz, 0, 1));
+}
+
+static int
+push0_sock_getopt_raw(void *arg, void *buf, size_t *szp)
+{
+	push0_sock *s = arg;
+	return (nni_getopt_int(s->raw, buf, szp));
+}
+
+static void
+push0_sock_send(void *arg, nni_aio *aio)
+{
+	push0_sock *s = arg;
+
+	nni_msgq_aio_put(s->uwq, aio);
+}
+
+static void
+push0_sock_recv(void *arg, nni_aio *aio)
+{
+	nni_aio_finish_error(aio, NNG_ENOTSUP);
+}
+
+static nni_proto_pipe_ops push0_pipe_ops = {
+	.pipe_init  = push0_pipe_init,
+	.pipe_fini  = push0_pipe_fini,
+	.pipe_start = push0_pipe_start,
+	.pipe_stop  = push0_pipe_stop,
+};
+
+static nni_proto_sock_option push0_sock_options[] = {
+	{
+	    .pso_name   = NNG_OPT_RAW,
+	    .pso_getopt = push0_sock_getopt_raw,
+	    .pso_setopt = push0_sock_setopt_raw,
+	},
+	// terminate list
+	{ NULL, NULL, NULL },
+};
+
+static nni_proto_sock_ops push0_sock_ops = {
+	.sock_init    = push0_sock_init,
+	.sock_fini    = push0_sock_fini,
+	.sock_open    = push0_sock_open,
+	.sock_close   = push0_sock_close,
+	.sock_options = push0_sock_options,
+	.sock_send    = push0_sock_send,
+	.sock_recv    = push0_sock_recv,
+};
+
+static nni_proto push0_proto = {
+	.proto_version  = NNI_PROTOCOL_VERSION,
+	.proto_self     = { NNI_PROTO_PUSH_V0, "push" },
+	.proto_peer     = { NNI_PROTO_PULL_V0, "pull" },
+	.proto_flags    = NNI_PROTO_FLAG_SND,
+	.proto_pipe_ops = &push0_pipe_ops,
+	.proto_sock_ops = &push0_sock_ops,
+};
+
+int
+nng_push0_open(nng_socket *sidp)
+{
+	return (nni_proto_open(sidp, &push0_proto));
+}
diff --git a/src/protocol/pipeline0/push.h b/src/protocol/pipeline0/push.h
new file mode 100644
index 00000000..c7303b92
--- /dev/null
+++ b/src/protocol/pipeline0/push.h
@@ -0,0 +1,28 @@
+//
+// Copyright 2017 Garrett D'Amore <garrett@damore.org>
+// Copyright 2017 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.
+//
+
+#ifndef NNG_PROTOCOL_PIPELINE0_PUSH_H
+#define NNG_PROTOCOL_PIPELINE0_PUSH_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+NNG_DECL int nng_push0_open(nng_socket *);
+
+#ifndef nng_push_open
+#define nng_push_open nng_push0_open
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // NNG_PROTOCOL_PIPELINE0_PUSH_H