fixes #4 Statistics support

This introduces new public APIs for obtaining statistics,
and adds some generic stats for dialers, listeners, pipes, and
sockets.  Also added are stats for inproc and pairv1 protocol.

The other protocols and transports will have stats added
incrementally as time goes on.

A simple test program, and man pages are provided for this.
Start by looking at nng_stat(5).

Statistics does have some impact, and they can be disabled by
using the advanced NNG_ENABLE_STATS (setting it to OFF, it's
ON by default) if you need to build a minimized configuration.

1 files changed, 47 insertions, 3 deletions

diff --git a/src/core/pipe.c b/src/core/pipe.c
index bdbc76e0..d623e158 100644
--- a/src/core/pipe.c
+++ b/src/core/pipe.c
@@ -11,6 +11,7 @@
 #include "core/nng_impl.h"
 #include "sockimpl.h"
 
+#include <stdio.h>
 #include <string.h>
 
 // This file contains functions relating to pipes.
@@ -82,6 +83,7 @@ pipe_destroy(nni_pipe *p)
 		p->p_tran_ops.p_stop(p->p_tran_data);
 	}
 
+	nni_stat_remove(&p->p_stats.s_root);
 	nni_pipe_remove(p);
 
 	if (p->p_proto_data != NULL) {
@@ -177,6 +179,28 @@ nni_pipe_peer(nni_pipe *p)
 	return (p->p_tran_ops.p_peer(p->p_tran_data));
 }
 
+void
+nni_pipe_stats_init(nni_pipe *p)
+{
+#ifdef NNG_ENABLE_STATS
+	nni_pipe_stats *st = &p->p_stats;
+
+	if (p->p_listener != NULL) {
+		st->s_ep_id.si_name  = "listener";
+		st->s_ep_id.si_desc  = "listener for pipe";
+		st->s_ep_id.si_value = nni_listener_id(p->p_listener);
+	} else {
+		st->s_ep_id.si_name  = "dialer";
+		st->s_ep_id.si_desc  = "dialer for pipe";
+		st->s_ep_id.si_value = nni_dialer_id(p->p_dialer);
+	}
+
+	nni_stat_append(NULL, &st->s_root);
+#else
+	NNI_ARG_UNUSED(p);
+#endif
+}
+
 int
 nni_pipe_create(nni_pipe **pp, nni_sock *sock, nni_tran *tran, void *tdata)
 {
@@ -184,7 +208,6 @@ nni_pipe_create(nni_pipe **pp, nni_sock *sock, nni_tran *tran, void *tdata)
 	int                 rv;
 	void *              sdata = nni_sock_proto_data(sock);
 	nni_proto_pipe_ops *pops  = nni_sock_proto_pipe_ops(sock);
-	uint64_t            id;
 
 	if ((p = NNI_ALLOC_STRUCT(p)) == NULL) {
 		// In this case we just toss the pipe...
@@ -210,12 +233,27 @@ nni_pipe_create(nni_pipe **pp, nni_sock *sock, nni_tran *tran, void *tdata)
 	nni_cv_init(&p->p_cv, &nni_pipe_lk);
 
 	nni_mtx_lock(&nni_pipe_lk);
-	if ((rv = nni_idhash_alloc(nni_pipes, &id, p)) == 0) {
-		p->p_id     = (uint32_t) id;
+	if ((rv = nni_idhash_alloc32(nni_pipes, &p->p_id, p)) == 0) {
 		p->p_refcnt = 1;
 	}
 	nni_mtx_unlock(&nni_pipe_lk);
 
+	nni_pipe_stats *st = &p->p_stats;
+	snprintf(st->s_scope, sizeof(st->s_scope), "pipe%u", p->p_id);
+
+	nni_stat_init_scope(&st->s_root, st->s_scope, "pipe statistics");
+
+	nni_stat_init_id(&st->s_id, "id", "pipe id", p->p_id);
+	nni_stat_append(&st->s_root, &st->s_id);
+
+	// name and description fleshed out later.
+	nni_stat_init_id(&st->s_ep_id, "", "", 0);
+	nni_stat_append(&st->s_root, &st->s_ep_id);
+
+	nni_stat_init_id(&st->s_sock_id, "socket", "socket for pipe",
+	    nni_sock_id(p->p_sock));
+	nni_stat_append(&st->s_root, &st->s_sock_id);
+
 	if ((rv != 0) || ((rv = tran->tran_pipe->p_init(tdata, p)) != 0) ||
 	    ((rv = pops->pipe_init(&p->p_proto_data, p, sdata)) != 0)) {
 		nni_pipe_close(p);
@@ -274,3 +312,9 @@ nni_pipe_dialer_id(nni_pipe *p)
 {
 	return (p->p_dialer ? nni_dialer_id(p->p_dialer) : 0);
 }
+
+void
+nni_pipe_add_stat(nni_pipe *p, nni_stat_item *item)
+{
+	nni_stat_append(&p->p_stats.s_root, item);
+}