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.)

1 files changed, 267 insertions, 0 deletions

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));
+}