Replaced old wacked-in-head system with proper reference counting for

client objects.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@1989 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/presents/data/ClientObject.dobj

@@ -1,11 +1,13 @@
 //
-// $Id: ClientObject.dobj,v 1.2 2002/09/19 23:36:59 mdb Exp $
+// $Id: ClientObject.dobj,v 1.3 2002/11/26 02:14:24 mdb Exp $
 
 package com.threerings.presents.data;
 
 import com.threerings.presents.dobj.DObject;
 import com.threerings.presents.dobj.DSet;
 
+import com.threerings.presents.Log;
+
 /**
  * Every client in the system has an associated client object to which
  * only they subscribe. The client object can be used to deliver messages
@@ -29,4 +31,32 @@ public class ClientObject extends DObject
     {
         return "(" + getOid() + ")";
     }
+
+    /**
+     * Used for reference counting client objects, adds a reference to
+     * this object.
+     */
+    public synchronized void reference ()
+    {
+        _references++;
+//         Log.info("Incremented references [who=" + who() +
+//                  ", refs=" + _references + "].");
+    }
+
+    /**
+     * Used for reference counting client objects, releases a reference to
+     * this object.
+     *
+     * @return true if the object has remaining references, false
+     * otherwise.
+     */
+    public synchronized boolean release ()
+    {
+//         Log.info("Decremented references [who=" + who() +
+//                  ", refs=" + (_references-1) + "].");
+        return (--_references > 0);
+    }
+
+    /** Used to reference count resolved client objects. */
+    protected transient int _references;
 }

src/java/com/threerings/presents/data/ClientObject.java

@@ -1,11 +1,13 @@
 //
-// $Id: ClientObject.java,v 1.4 2002/09/19 23:36:59 mdb Exp $
+// $Id: ClientObject.java,v 1.5 2002/11/26 02:14:24 mdb Exp $
 
 package com.threerings.presents.data;
 
 import com.threerings.presents.dobj.DObject;
 import com.threerings.presents.dobj.DSet;
 
+import com.threerings.presents.Log;
+
 /**
  * Every client in the system has an associated client object to which
  * only they subscribe. The client object can be used to deliver messages
@@ -33,6 +35,34 @@ public class ClientObject extends DObject
         return "(" + getOid() + ")";
     }
 
+    /**
+     * Used for reference counting client objects, adds a reference to
+     * this object.
+     */
+    public synchronized void reference ()
+    {
+        _references++;
+//         Log.info("Incremented references [who=" + who() +
+//                  ", refs=" + _references + "].");
+    }
+
+    /**
+     * Used for reference counting client objects, releases a reference to
+     * this object.
+     *
+     * @return true if the object has remaining references, false
+     * otherwise.
+     */
+    public synchronized boolean release ()
+    {
+//         Log.info("Decremented references [who=" + who() +
+//                  ", refs=" + (_references-1) + "].");
+        return (--_references > 0);
+    }
+
+    /** Used to reference count resolved client objects. */
+    protected transient int _references;
+
     /**
      * Requests that the specified entry be added to the
      * <code>receivers</code> set. The set will not change until the event is

src/java/com/threerings/presents/server/ClientManager.java

@@ -1,5 +1,5 @@
 //
-// $Id: ClientManager.java,v 1.26 2002/11/05 02:17:56 mdb Exp $
+// $Id: ClientManager.java,v 1.27 2002/11/26 02:14:25 mdb Exp $
 
 package com.threerings.presents.server;
 
@@ -135,7 +135,9 @@ public class ClientManager
      * If the client object is already resolved, the request will be
      * processed immediately, otherwise the appropriate client object will
      * be instantiated and populated by the registered client resolver
-     * (which may involve talking to databases).
+     * (which may involve talking to databases). <em>Note:</em> this
+     * <b>must</b> be paired with a call to {@link #releaseClientObject}
+     * when the caller is finished with the client object.
      */
     public synchronized void resolveClientObject (
         String username, ClientResolutionListener listener)
@@ -144,6 +146,7 @@ public class ClientManager
         String key = toKey(username);
         ClientObject clobj = (ClientObject)_objmap.get(key);
         if (clobj != null) {
+            clobj.reference();
             listener.clientResolved(username, clobj);
             return;
         }
@@ -189,67 +192,34 @@ public class ClientManager
     }
 
     /**
-     * If an entity resolves a client object outside the scope of a normal
+     * Releases a client object that was obtained via a call to {@link
-     * client session, it should call this to unmap the client object when
+     * #resolveClientObject}. If this caller is the last reference, the
-     * it's finished. This won't actually unmap the client if someone came
+     * object will be flushed and destroyed.
-     * along and started a session for that client in the meanwhile, but
-     * if it does unmap the client it will also destroy the client object
-     * (finishing the job, as it were).
      */
-    public synchronized void unmapClientObject (String username)
+    public void releaseClientObject (String username)
     {
-        // we only remove the mapping if there's not a session in progress
-        // (which is indicated by an entry in the locks table)
         String key = toKey(username);
-        if (_locks.contains(key)) {
+        ClientObject clobj = (ClientObject)_objmap.get(key);
+        if (clobj == null) {
+            Log.warning("Requested to release unmapped client object " +
+                        "[username=" + username + "].");
+            Thread.dumpStack();
             return;
         }
 
-        ClientObject clobj = (ClientObject)_objmap.remove(key);
+        // decrement the reference count and stop here if there are
-        if (clobj != null) {
+        // remaining references
-            PresentsServer.omgr.destroyObject(clobj.getOid());
+        if (clobj.release()) {
-        } else {
+            return;
-            Log.warning("Requested to unmap non-existent client object " +
-                        "[username=" + username + "].");
         }
-    }
 
-    /**
+        Log.debug("Destroying client " + clobj.who() + ".");
-     * When a client object becomes part of an active session, this method
-     * should be called to ensure that it is not unloaded by any entities
-     * that temporarily resolve and release the object. This is called
-     * automatically when a real user starts a session by establishing a
-     * network connection with the server. If a client session is managed
-     * via some other mechanism (bots managed by the server, for example),
-     * this method and its corresponding {@link #releaseClientObject}
-     * should be called at the beginning and end of the faked client
-     * session respectively.
-     */
-    public synchronized void lockClientObject (String username)
-    {
-        String key = toKey(username);
-        if (_locks.contains(key)) {
-            Log.warning("Requested to lock already locked user " +
-                        "[username=" + username + "].");
-            Thread.dumpStack();
 
-        } else {
+        // we're all clear to go; remove the mapping
-            _locks.add(key);
+        _objmap.remove(key);
-        }
-    }
 
-    /**
+        // and destroy the object itself
-     * Releases a client object when their session has ended.
+        PresentsServer.omgr.destroyObject(clobj.getOid());
-     *
-     * @see #lockClientObject
-     */
-    public synchronized void releaseClientObject (String username)
-    {
-        if (!_locks.remove(toKey(username))) {
-            Log.warning("Requested to unlock a user that was not locked " +
-                        "[username=" + username + "].");
-            Thread.dumpStack();
-        }
     }
 
     // documentation inherited
@@ -355,21 +325,12 @@ public class ClientManager
         if (rc == null) {
             Log.warning("Unregistered client ended session " + client + ".");
             Thread.dumpStack();
-
-            // if they weren't in the username mapping, bail out now
-            // because the subsequent unmappings would just fail if we
-            // tried to do them for an unmapped client
-            return;
-
         } else if (rc != client) {
             Log.warning("Different clients with same username!? " +
                         "[c1=" + rc + ", c2=" + client + "].");
         } else {
             Log.info("Ending session " + client + ".");
         }
-
-        // unmap (and destroy) the client object
-        unmapClientObject(username);
     }
 
     /**

src/java/com/threerings/presents/server/ClientResolver.java

@@ -1,5 +1,5 @@
 //
-// $Id: ClientResolver.java,v 1.1 2002/03/05 05:33:25 mdb Exp $
+// $Id: ClientResolver.java,v 1.2 2002/11/26 02:14:25 mdb Exp $
 
 package com.threerings.presents.server;
 
@@ -99,6 +99,8 @@ public class ClientResolver extends Invoker.Unit
                 ClientResolutionListener crl = (ClientResolutionListener)
                     _listeners.get(i);
                 try {
+                    // add a reference for each listener
+                    _clobj.reference();
                     crl.clientResolved(_username, _clobj);
                 } catch (Exception e) {
                     Log.warning("Client resolution listener choked during " +

src/java/com/threerings/presents/server/PresentsClient.java

@@ -1,5 +1,5 @@
 //
-// $Id: PresentsClient.java,v 1.44 2002/11/05 05:47:36 mdb Exp $
+// $Id: PresentsClient.java,v 1.45 2002/11/26 02:14:25 mdb Exp $
 
 package com.threerings.presents.server;
 
@@ -154,20 +154,13 @@ public class PresentsClient
                 // call down to any derived classes
                 clientObjectWillChange(_clobj, clobj);
 
-                // release our old client object
+                // release our old client object; this will destroy it
                 _cmgr.releaseClientObject(_username);
 
-                // unmap the old client object; this will destroy it and
-                // clear out our username mapping
-                _cmgr.unmapClientObject(_username);
-
                 // update our internal fields
                 _username = username;
                 _clobj = clobj;
 
-                // lock our new client object
-                _cmgr.lockClientObject(_username);
-
                 // call down to any derived classes
                 clientObjectDidChange(_clobj);
 
@@ -234,10 +227,6 @@ public class PresentsClient
         // obtain our starting username
         assignStartingUsername();
 
-        // obtain a lock for our username->client object mapping while we
-        // have an active session
-        cmgr.lockClientObject(_username);
-
         // resolve our client object before we get fully underway
         cmgr.resolveClientObject(_username, this);
 
@@ -448,11 +437,10 @@ public class PresentsClient
         // about to generate
         clearSubscrips();
 
-        // release our locked client object
+        // release (and destroy) our client object
         _cmgr.releaseClientObject(_username);
 
-        // then let the client manager know what's up (it will take care
+        // let the client manager know that we're audi 5000
-        // of destroying our client object for us)
         _cmgr.clientDidEndSession(this);
 
         // clear out the client object so that we know the session is over