From f597cfe33d80e2a63430b155115715aa36775293 Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonygarnockjones@gmail.com>
Date: Fri, 11 May 2012 14:58:16 -0400
Subject: [PATCH] Driver now only creates resources for fully grounded local
 addresses.

---
 os2-tcp.rkt | 35 ++++++++++++++++++++++-------------
 1 file changed, 22 insertions(+), 13 deletions(-)

diff --git a/os2-tcp.rkt b/os2-tcp.rkt
index f4ed966..4a306a9 100644
--- a/os2-tcp.rkt
+++ b/os2-tcp.rkt
@@ -6,6 +6,7 @@
 (require (prefix-in tcp: racket/tcp))
 (require racket/port)
 (require "os2.rkt")
+(require "unify.rkt")
 (require "dump-bytes.rkt")
 
 (provide (struct-out tcp-address)
@@ -100,10 +101,11 @@
 ;; Topic Set<HandleMapping> (TcpAddress TcpAddress -> BootK) -> Transition
 (define (maybe-spawn-socket t active-handles driver-fun)
   (match t
-    [(or (topic 'publisher (tcp-channel local-addr remote-addr _) counterparty-virtual?)
-	 (topic 'subscriber (tcp-channel remote-addr local-addr _) counterparty-virtual?))
+    [(or (topic 'publisher (tcp-channel local-addr remote-addr _) _)
+	 (topic 'subscriber (tcp-channel remote-addr local-addr _) _))
      (cond
-      [counterparty-virtual? active-handles]
+      [(ground? remote-addr) active-handles]
+      [(not (ground? local-addr)) active-handles]
       [(set-member? active-handles (cons local-addr remote-addr)) active-handles]
       [else
        (transition (set-add active-handles (cons local-addr remote-addr))
@@ -113,10 +115,11 @@
 ;; Topic Set<HandleMapping> -> Transition
 (define (maybe-forget-socket t active-handles)
   (match t
-    [(or (topic 'publisher (tcp-channel local-addr _ _) counterparty-virtual?)
-	 (topic 'subscriber (tcp-channel _ local-addr _) counterparty-virtual?))
+    [(or (topic 'publisher (tcp-channel local-addr remote-addr _) _)
+	 (topic 'subscriber (tcp-channel remote-addr local-addr _) _))
      (cond
-      [counterparty-virtual? active-handles]
+      [(ground? remote-addr) active-handles]
+      [(not (ground? local-addr)) active-handles]
       [else (set-remove active-handles local-addr)])]))
 
 ;; TcpAddress TcpAddress -> BootK
@@ -128,13 +131,19 @@
 	(set (topic-subscriber (tcp-channel local-addr any-remote (wild)) #:virtual? #t)
 	     (topic-publisher (tcp-channel any-remote local-addr (wild)) #:virtual? #t))
       #:state state
-      #:on-absence (transition 'listener-is-closed
-		     (kill)
-		     (when (eq? state 'listener-is-running)
-		       (spawn (lambda (dummy-pid)
-				(tcp:tcp-close listener)
-				(transition 'dummy (kill)))
-			      #:debug-name (list 'tcp-listener-closer local-addr)))))
+      #:topic t
+      #:on-absence (match t
+		     [(or (topic 'publisher (tcp-channel (== local-addr) remote-addr _) _)
+			  (topic 'subscriber (tcp-channel remote-addr (== local-addr) _) _))
+		      (if (ground? remote-addr)
+			  state
+			  (transition 'listener-is-closed
+			    (kill)
+			    (when (eq? state 'listener-is-running)
+			      (spawn (lambda (dummy-pid)
+				       (tcp:tcp-close listener)
+				       (transition 'dummy (kill)))
+				     #:debug-name (list 'tcp-listener-closer local-addr)))))]))
     (role 'accepter (topic-subscriber (cons (tcp:tcp-accept-evt listener) (wild)))
       #:state state
       [(cons _ (list cin cout))