fixes #2 Websocket transport

This is a rather large changeset -- it fundamentally adds websocket
transport, but as part of this changeset we added a generic framework
for both HTTP and websocket.  We also made some supporting changes to
the core, such as changing the way timeouts work for AIOs and adding
additional state keeping for AIOs, and adding a common framework for
deferred finalization (to avoid certain kinds of circular deadlocks
during resource cleanup).  We also invented a new initialization framework
so that we can avoid wiring in knowledge about them into the master
initialization framework.

The HTTP framework is not yet complete, but it is good enough for simple
static serving and building additional services on top of -- including
websocket.  We expect both websocket and HTTP support to evolve
considerably, and so these are not part of the public API yet.

Property support for the websocket transport (in particular address
properties) is still missing, as is support for TLS.

The websocket transport here is a bit more robust than the original
nanomsg implementation, as it supports multiple sockets listening at
the same port sharing the same HTTP server instance, discriminating
between them based on URI (and possibly the virtual host).

Websocket is enabled by default at present, and work to conditionalize
HTTP and websocket further (to minimize bloat) is still pending.

1 files changed, 6 insertions, 1 deletions

diff --git a/src/core/list.c b/src/core/list.c
index 8b26b64a..f489a705 100644
--- a/src/core/list.c
+++ b/src/core/list.c
@@ -1,5 +1,7 @@
 //
 // Copyright 2017 Garrett D'Amore <garrett@damore.org>
+// Copyright 2017 Capitar IT Group BV <info@capitar.com>
+// Copyright 2017 Staysail Systems, Inc. <info@staysail.tech>
 //
 // This software is supplied under the terms of the MIT License, a
 // copy of which should be located in the distribution where this
@@ -151,7 +153,10 @@ nni_list_active(nni_list *list, void *item)
 int
 nni_list_empty(nni_list *list)
 {
-	return (list->ll_head.ln_next == &list->ll_head);
+	// The first check ensures that we treat an uninitialized list
+	// as empty.  This use useful for statically initialized lists.
+	return ((list->ll_head.ln_next == NULL) ||
+	    (list->ll_head.ln_next == &list->ll_head));
 }
 
 int