SUB protocol implemented (uses sorted linked list for topics).

5 files changed, 386 insertions, 0 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index a1c0fac7..f07a6696 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -67,6 +67,8 @@ set (NNG_SOURCES
 
     protocol/pair/pair.c
 
+    protocol/pubsub/sub.c
+
     protocol/reqrep/rep.c
     protocol/reqrep/req.c
 
diff --git a/src/core/list.c b/src/core/list.c
index ca200415..b1adf2cd 100644
--- a/src/core/list.c
+++ b/src/core/list.c
@@ -83,6 +83,38 @@ nni_list_prepend(nni_list *list, void *item)
 }
 
 
+void
+nni_list_insert_before(nni_list *list, void *item, void *before)
+{
+	nni_list_node *node = NODE(list, item);
+	nni_list_node *where = NODE(list, before);
+
+	if ((node->ln_next != NULL) || (node->ln_prev != NULL)) {
+		nni_panic("prepending node already on a list or not inited");
+	}
+	node->ln_next = where;
+	node->ln_prev = where->ln_prev;
+	node->ln_next->ln_prev = node;
+	node->ln_prev->ln_next = node;
+}
+
+
+void
+nni_list_insert_after(nni_list *list, void *item, void *after)
+{
+	nni_list_node *node = NODE(list, item);
+	nni_list_node *where = NODE(list, after);
+
+	if ((node->ln_next != NULL) || (node->ln_prev != NULL)) {
+		nni_panic("prepending node already on a list or not inited");
+	}
+	node->ln_prev = where;
+	node->ln_next = where->ln_next;
+	node->ln_next->ln_prev = node;
+	node->ln_prev->ln_next = node;
+}
+
+
 void *
 nni_list_next(const nni_list *list, void *item)
 {
diff --git a/src/core/list.h b/src/core/list.h
index a6540f5e..7d8b50be 100644
--- a/src/core/list.h
+++ b/src/core/list.h
@@ -36,6 +36,8 @@ extern void *nni_list_first(const nni_list *);
 extern void *nni_list_last(const nni_list *);
 extern void nni_list_append(nni_list *, void *);
 extern void nni_list_prepend(nni_list *, void *);
+extern void nni_list_insert_before(nni_list *, void *, void *);
+extern void nni_list_insert_after(nni_list *, void *, void *);
 extern void *nni_list_next(const nni_list *, void *);
 extern void *nni_list_prev(const nni_list *, void *);
 extern void nni_list_remove(nni_list *, void *);
diff --git a/src/core/protocol.c b/src/core/protocol.c
index 27430771..765c2e9a 100644
--- a/src/core/protocol.c
+++ b/src/core/protocol.c
@@ -19,11 +19,13 @@
 extern nni_proto nni_pair_proto;
 extern nni_proto nni_rep_proto;
 extern nni_proto nni_req_proto;
+extern nni_proto nni_sub_proto;
 
 static nni_proto *protocols[] = {
 	&nni_pair_proto,
 	&nni_rep_proto,
 	&nni_req_proto,
+	&nni_sub_proto,
 	NULL
 };
 
diff --git a/src/protocol/pubsub/sub.c b/src/protocol/pubsub/sub.c
new file mode 100644
index 00000000..a1f23607
--- /dev/null
+++ b/src/protocol/pubsub/sub.c
@@ -0,0 +1,348 @@
+//
+// Copyright 2016 Garrett D'Amore <garrett@damore.org>
+//
+// 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"
+
+// Subscriber protocol.  The SUB protocol receives messages sent to
+// it from publishers, and filters out those it is not interested in,
+// only passing up ones that match known subscriptions.
+
+typedef struct nni_sub_pipe	nni_sub_pipe;
+typedef struct nni_sub_sock	nni_sub_sock;
+typedef struct nni_sub_topic	nni_sub_topic;
+
+struct nni_sub_topic {
+	nni_list_node	node;
+	size_t		len;
+	void *		buf;
+};
+
+// An nni_rep_sock is our per-socket protocol private structure.
+struct nni_sub_sock {
+	nni_sock *	sock;
+	nni_mtx		mx;
+	nni_list	topics;
+	nni_msgq *	urq;
+	int		raw;
+};
+
+// An nni_rep_pipe is our per-pipe protocol private structure.
+struct nni_sub_pipe {
+	nni_pipe *	pipe;
+	nni_sub_sock *	sub;
+};
+
+static int
+nni_sub_init(void **subp, nni_sock *sock)
+{
+	nni_sub_sock *sub;
+	int rv;
+
+	if ((sub = NNI_ALLOC_STRUCT(sub)) == NULL) {
+		return (NNG_ENOMEM);
+	}
+	if ((rv = nni_mtx_init(&sub->mx)) != 0) {
+		NNI_FREE_STRUCT(sub);
+		return (rv);
+	}
+	NNI_LIST_INIT(&sub->topics, nni_sub_topic, node);
+	sub->sock = sock;
+	sub->raw = 0;
+
+	sub->urq = nni_sock_recvq(sock);
+	nni_sock_senderr(sock, NNG_ENOTSUP);
+	*subp = sub;
+	return (0);
+}
+
+
+static void
+nni_sub_fini(void *arg)
+{
+	nni_sub_sock *sub = arg;
+
+	// XXX: free subscriptions...
+	nni_mtx_fini(&sub->mx);
+	NNI_FREE_STRUCT(sub);
+}
+
+
+static int
+nni_sub_pipe_init(void **spp, nni_pipe *pipe, void *ssock)
+{
+	nni_sub_pipe *sp;
+	int rv;
+
+	if ((sp = NNI_ALLOC_STRUCT(sp)) == NULL) {
+		return (NNG_ENOMEM);
+	}
+	sp->pipe = pipe;
+	sp->sub = ssock;
+	*spp = sp;
+	return (0);
+}
+
+
+static void
+nni_sub_pipe_fini(void *arg)
+{
+	nni_sub_pipe *sp = arg;
+
+	NNI_FREE_STRUCT(sp);
+}
+
+
+static int
+nni_sub_pipe_add(void *arg)
+{
+	nni_sub_pipe *sp = arg;
+
+	if (nni_pipe_peer(sp->pipe) != NNG_PROTO_PUB) {
+		return (NNG_EPROTO);
+	}
+	return (0);
+}
+
+
+static void
+nni_sub_pipe_rem(void *arg)
+{
+	NNI_ARG_UNUSED(arg);
+}
+
+
+static void
+nni_sub_pipe_send(void *arg)
+{
+	NNI_ARG_UNUSED(arg);
+}
+
+
+static void
+nni_sub_pipe_recv(void *arg)
+{
+	nni_sub_pipe *sp = arg;
+	nni_sub_sock *sub = sp->sub;
+	nni_msgq *urq = sub->urq;
+	nni_pipe *pipe = sp->pipe;
+	nni_msg *msg;
+	int rv;
+
+	for (;;) {
+		rv = nni_pipe_recv(pipe, &msg);
+		if (rv != 0) {
+			break;
+		}
+
+		// Now send it up.
+		rv = nni_msgq_put(urq, msg);
+		if (rv != 0) {
+			nni_msg_free(msg);
+			break;
+		}
+	}
+	// Nobody else to signal...
+	nni_pipe_close(pipe);
+}
+
+
+// For now we maintain subscriptions on a sorted linked list.  As we do not
+// expect to have huge numbers of subscriptions, and as the operation is
+// really O(n), we think this is acceptable.  In the future we might decide
+// to replace this with a patricia trie, like old nanomsg had.
+
+static int
+nni_sub_subscribe(nni_sub_sock *sub, const void *buf, size_t sz)
+{
+	nni_sub_topic *topic;
+	nni_sub_topic *newtopic;
+
+	NNI_LIST_FOREACH (&sub->topics, topic) {
+		int rv;
+		if (topic->len >= sz) {
+			rv = memcmp(topic->buf, buf, sz);
+		} else {
+			rv = memcmp(topic->buf, buf, topic->len);
+		}
+		if (rv == 0) {
+			if (topic->len == sz) {
+				// Already inserted.
+				return (0);
+			}
+			if (topic->len > sz) {
+				break;
+			}
+		} else if (rv > 0) {
+			break;
+		}
+	}
+
+	if ((newtopic = NNI_ALLOC_STRUCT(newtopic)) == NULL) {
+		return (NNG_ENOMEM);
+	}
+	if ((newtopic->buf = nni_alloc(sz)) == NULL) {
+		return (NNG_ENOMEM);
+	}
+	NNI_LIST_NODE_INIT(&newtopic->node);
+	newtopic->len = sz;
+	if (topic != NULL) {
+		nni_list_insert_before(&sub->topics, newtopic, topic);
+	}
+	return (0);
+}
+
+
+static int
+nni_sub_unsubscribe(nni_sub_sock *sub, const void *buf, size_t sz)
+{
+	nni_sub_topic *topic;
+	int rv;
+
+	NNI_LIST_FOREACH (&sub->topics, topic) {
+		if (topic->len >= sz) {
+			rv = memcmp(topic->buf, buf, sz);
+		} else {
+			rv = memcmp(topic->buf, buf, topic->len);
+		}
+		if (rv == 0) {
+			if (topic->len == sz) {
+				nni_list_remove(&sub->topics, topic);
+				nni_free(topic->buf, topic->len);
+				NNI_FREE_STRUCT(topic);
+				return (0);
+			}
+			if (topic->len > sz) {
+				return (NNG_ENOENT);
+			}
+		}
+		if (rv > 0) {
+			return (NNG_ENOENT);
+		}
+	}
+	return (NNG_ENOENT);
+}
+
+
+static int
+nni_sub_setopt(void *arg, int opt, const void *buf, size_t sz)
+{
+	nni_sub_sock *sub = arg;
+	int rv;
+
+	switch (opt) {
+	case NNG_OPT_RAW:
+		nni_mtx_lock(&sub->mx);
+		rv = nni_setopt_int(&sub->raw, buf, sz, 0, 1);
+		nni_mtx_unlock(&sub->mx);
+		break;
+	case NNG_OPT_SUBSCRIBE:
+		nni_mtx_lock(&sub->mx);
+		rv = nni_sub_subscribe(sub, buf, sz);
+		nni_mtx_unlock(&sub->mx);
+		break;
+	case NNG_OPT_UNSUBSCRIBE:
+		nni_mtx_lock(&sub->mx);
+		rv = nni_sub_unsubscribe(sub, buf, sz);
+		nni_mtx_unlock(&sub->mx);
+		break;
+	default:
+		rv = NNG_ENOTSUP;
+	}
+	return (rv);
+}
+
+
+static int
+nni_sub_getopt(void *arg, int opt, void *buf, size_t *szp)
+{
+	nni_sub_sock *sub = arg;
+	int rv;
+
+	switch (opt) {
+	case NNG_OPT_RAW:
+		nni_mtx_lock(&sub->mx);
+		rv = nni_getopt_int(&sub->raw, buf, szp);
+		nni_mtx_unlock(&sub->mx);
+		break;
+	default:
+		rv = NNG_ENOTSUP;
+	}
+	return (rv);
+}
+
+
+static nni_msg *
+nni_sub_recvfilter(void *arg, nni_msg *msg)
+{
+	nni_sub_sock *sub = arg;
+	nni_sub_topic *topic;
+	char *body;
+	size_t len;
+	int match;
+
+	nni_mtx_lock(&sub->mx);
+	if (sub->raw) {
+		nni_mtx_unlock(&sub->mx);
+		return (msg);
+	}
+
+	body = nni_msg_body(msg, &len);
+
+	// Check to see if the message matches one of our subscriptions.
+	NNI_LIST_FOREACH (&sub->topics, topic) {
+		if (len >= topic->len) {
+			int rv = memcmp(topic->buf, body, topic->len);
+			if (rv == 0) {
+				// Matched!
+				match = 1;
+				break;
+			}
+			if (rv > 0) {
+				match = 0;
+				break;
+			}
+		} else if (memcmp(topic->buf, body, len) >= 0) {
+			match = 0;
+			break;
+		}
+	}
+	nni_mtx_unlock(&sub->mx);
+	if (!match) {
+		nni_msg_free(msg);
+		return (NULL);
+	}
+	return (0);
+}
+
+
+// This is the global protocol structure -- our linkage to the core.
+// This should be the only global non-static symbol in this file.
+static nni_proto_pipe nni_sub_proto_pipe = {
+	.pipe_init	= nni_sub_pipe_init,
+	.pipe_fini	= nni_sub_pipe_fini,
+	.pipe_add	= nni_sub_pipe_add,
+	.pipe_rem	= nni_sub_pipe_rem,
+	.pipe_send	= nni_sub_pipe_send,
+	.pipe_recv	= nni_sub_pipe_recv,
+};
+
+nni_proto nni_sub_proto = {
+	.proto_self		= NNG_PROTO_SUB,
+	.proto_peer		= NNG_PROTO_PUB,
+	.proto_name		= "sub",
+	.proto_pipe		= &nni_sub_proto_pipe,
+	.proto_init		= nni_sub_init,
+	.proto_fini		= nni_sub_fini,
+	.proto_setopt		= nni_sub_setopt,
+	.proto_getopt		= nni_sub_getopt,
+	.proto_recv_filter	= nni_sub_recvfilter,
+};