Use a map of maps for collections of transports.

2 files changed, 50 insertions, 9 deletions

diff --git a/src/org/gnu/clojure/gnunet/hello.clj b/src/org/gnu/clojure/gnunet/hello.clj
index 6370954..3630b23 100644
--- a/src/org/gnu/clojure/gnunet/hello.clj
+++ b/src/org/gnu/clojure/gnunet/hello.clj
@@ -1,6 +1,7 @@
 (ns org.gnu.clojure.gnunet.hello
   (:use (org.gnu.clojure.gnunet parser message identity crypto)
-    clojure.contrib.monads))
+    clojure.contrib.monads)
+  (:import java.util.Date))
 
 (def message-type-hello 16)
 
@@ -21,13 +22,54 @@
      :expiration expiration
      :bytes encoded-address}))
 
+(defn list-transports
+  "Generate a list of transport descriptions."
+  [transport-map]
+  (for [transport transport-map
+        address (val transport)]
+    {:name (key transport)
+     :bytes (key address)
+     :expiration (val address)}))
+
 (defn encode-hello
   "Encode a hello message."
   [hello]
   (concat
     (encode-int32 0)
     (encode-rsa-public-key (:public-key hello))
-    (mapcat encode-transport (:transports hello))))
+    (mapcat encode-transport (list-transports (:transports hello)))))
+
+(defn my-max
+  "Return the maximum in a collection of comparable values."
+  [& coll]
+  (last (sort coll)))
+
+(defn merge-transports
+  "Merge a list of transport descriptions into a map of maps of
+   expiration times, keyed first by transport name and then by
+   transport address, and then filter by min-expiration"
+  [min-expiration transport-map transport-list]
+  (reduce (fn [transport-map transport]
+            (let [addresses (transport-map
+                              (:name transport)
+                              {(:bytes transport) (:expiration transport)})
+                  expiration (addresses
+                               (:bytes transport)
+                               (:expiration transport))]
+              (if (and
+                    (< 0 (compare min-expiration expiration))
+                    (< 0 (compare min-expiration (:expiration transport))))
+                (let [less-addresses (dissoc addresses (:bytes transport))]
+                  (if (empty? less-addresses)
+                    (dissoc transport-map (:name transport))
+                    (assoc transport-map (:name transport) less-addresses)))
+                (assoc transport-map
+                  (:name transport)
+                  (assoc addresses
+                    (:bytes transport)
+                    (my-max (:expiration transport) expiration))))))
+    transport-map
+    transport-list))
 
 (def parse-hello
   (domonad parser-m [padding parse-uint32
@@ -35,4 +77,4 @@
                      public-key parse-rsa-public-key
                      transports (none-or-more parse-transport)]
     {:public-key public-key
-     :transports transports}))
+     :transports (merge-transports (Date. (long 0)) {} transports)}))
diff --git a/src/org/gnu/clojure/gnunet/peer.clj b/src/org/gnu/clojure/gnunet/peer.clj
index 0c3a0d6..7859826 100644
--- a/src/org/gnu/clojure/gnunet/peer.clj
+++ b/src/org/gnu/clojure/gnunet/peer.clj
@@ -1,5 +1,5 @@
 (ns org.gnu.clojure.gnunet.peer
-  (:use (org.gnu.clojure.gnunet identity))
+  (:use (org.gnu.clojure.gnunet identity hello))
   (:import java.util.Date))
 
 (defstruct remote-peer
@@ -27,19 +27,18 @@
   (struct-map peer
     :public-key (.getPublic (:keypair options))
     :id (generate-id (.getPublic (:keypair options)))
-    :transports-agent (agent [])
+    :transports-agent (agent {})
     :private-key (.getPrivate (:keypair options))
     :remote-peers-agent (agent {})))
 
-(def filter-expired-transports
-  (partial filter #(< (:expiration %) (Date.))))
-
 ;; Event - Peer receives a HELLO message
 (defn admit-hello!
   [peer hello]
   (letfn [(update-transports
             [transports new-transports]
-            (filter-expired-transports (concat transports new-transports)))
+            (merge-transports (Date.)
+              transports
+              (list-transports new-transports)))
           (update-remote-peers
             [remote-peers hello]
             (let [id (vec (generate-id (:public-key hello)))