Allow callers to detect when a client is about to die even though it is connected and logged on. This allows handling of the edge case where a client is getting throttled.

git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@5897 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/as/com/threerings/presents/client/Client.as

@@ -243,6 +243,16 @@ public class Client extends EventDispatcher
         return _comm != null && _comm.isConnected();
     }
 
+    /**
+     * Detects if we have an external logoff request waiting to go through. If the connection is
+     * being throttled, this may return true even though the client <code>isLoggedOn() &&
+     * isConnected()</code>.
+     */
+    public function isLogoffPending () :Boolean
+    {
+        return _switcher == null && _comm != null && _comm.hasPendingLogoff();
+    }
+
     /**
      * Requests that this client connect and logon to the server with which it was previously
      * configured.

src/as/com/threerings/presents/client/Communicator.as

@@ -95,6 +95,21 @@ public class Communicator
         return _writer != null;
     }
 
+    /**
+     * Detects is the communicator has a logoff request pending, i.e. will logoff in the near
+     * future.
+     */
+    public function hasPendingLogoff () :Boolean
+    {
+        // check for a logoff message
+        for each (var message :UpstreamMessage in _outq) {
+            if (message is LogoffRequest) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     /**
      * Attempts to logon on using the port at the specified index.
      */
@@ -287,13 +302,11 @@ public class Communicator
         _portIdx = -1;
 
         // check for a logoff message
-        for each (var message :UpstreamMessage in _outq) {
-            if (message is LogoffRequest) {
-                // don't bother authing, just bail
-                log.info("Logged off prior to socket opening, shutting down");
-                shutdown(null);
-                return;
-            }
+        if (hasPendingLogoff()) {
+            // don't bother authing, just bail
+            log.info("Logged off prior to socket opening, shutting down");
+            shutdown(null);
+            return;
         }
 
         // send our authentication request (do so directly rather than putting it on the outgoing