For EZ property sets, added a setter that performs an "atomic" test-and-set:

it's atomic in the sense that a single server event will test the variable, 
and only set it if the previous value was null (i.e. didn't exist). 
This allows for a level of elementary synchronization between the clients.

The new function on EZGameControl is:
  _gameCtrl.testAndSet (propertyName, newValue[, index])

I hoped to generalize this to test against arbitrary values, but that's 
significantly harder, since properties accept numerous types as values,
and those can have different representations on the client and the server.
So it remains a check against null until we need to generalize it. :)





git-svn-id: svn+ssh://src.earth.threerings.net/vilya/trunk@193 c613c5cb-e716-0410-b11b-feb51c14d237

src/as/com/threerings/ezgame/EZGameControl.as

@@ -157,7 +157,20 @@ public class EZGameControl extends EventDispatcher
      */
     public function set (propName :String, value :Object, index :int = -1) :void
     {
-        callEZCode("setProperty_v1", propName, value, index);
+        callEZCode("setProperty_v2", propName, value, index, false);
+    }
+
+    /**
+     * Set a property that will be distributed, but only if it was null before.
+     *
+     * The operation is 'atomic', in the sense that testing and setting take place
+     * during the same server event. In comparison, a separate 'get' followed by
+     * a 'set' operation would involve two events with two network round-trips,
+     * and no guarantee that the value won't change between the events.
+     */
+    public function testAndSet (propName :String, value :Object, index :int = -1) :void
+    {
+        callEZCode("setProperty_v2", propName, value, index, true);
     }
 
     /**

src/as/com/threerings/ezgame/client/EZGameService.as

@@ -67,7 +67,7 @@ public interface EZGameService extends InvocationService
     function setCookie (arg1 :Client, arg2 :ByteArray, arg3 :InvocationService_InvocationListener) :void;
 
     // from Java interface EZGameService
-    function setProperty (arg1 :Client, arg2 :String, arg3 :Object, arg4 :int, arg5 :InvocationService_InvocationListener) :void;
+    function setProperty (arg1 :Client, arg2 :String, arg3 :Object, arg4 :int, arg5 :Boolean, arg6 :InvocationService_InvocationListener) :void;
 
     // from Java interface EZGameService
     function setTicker (arg1 :Client, arg2 :String, arg3 :int, arg4 :InvocationService_InvocationListener) :void;

src/as/com/threerings/ezgame/client/GameControlBackend.as

@@ -72,7 +72,7 @@ public class GameControlBackend
     {
         _ctx = ctx;
         _ezObj = ezObj;
-        _gameData = new GameData(setProperty_v1, _ezObj.getUserProps());
+        _gameData = new GameData(setProperty_v2, _ezObj.getUserProps());
 
         _ezObj.addListener(this);
         _ctx.getClient().getClientObject().addListener(_userListener);
@@ -136,7 +136,7 @@ public class GameControlBackend
         o["gameData"] = _gameData;
 
         // functions
-        o["setProperty_v1"] = setProperty_v1;
+        o["setProperty_v2"] = setProperty_v2;
         o["mergeCollection_v1"] = mergeCollection_v1;
         o["setTicker_v1"] = setTicker_v1;
         o["sendChat_v1"] = sendChat_v1;
@@ -163,18 +163,18 @@ public class GameControlBackend
         o["getPlayers_v1"] = getPlayers_v1;
     }
 
-    public function setProperty_v1 (
-        propName :String, value :Object, index :int) :void
+    public function setProperty_v2 (
+        propName :String, value :Object, index :int, testAndSet :Boolean) :void
     {
         validatePropertyChange(propName, value, index);
 
         var encoded :Object = EZObjectMarshaller.encode(value, (index == -1));
         _ezObj.ezGameService.setProperty(
-            _ctx.getClient(), propName, encoded, index,
+            _ctx.getClient(), propName, encoded, index, testAndSet,
             createLoggingConfirmListener("setProperty"));
 
         // set it immediately in the game object
-        _ezObj.applyPropertySet(propName, value, index);
+        _ezObj.applyPropertySet(propName, value, index, testAndSet);
     }
 
     public function mergeCollection_v1 (

src/as/com/threerings/ezgame/client/GameData.as

@@ -67,7 +67,7 @@ public class GameData extends Proxy
 
     override flash_proxy function setProperty (propName :*, value :*) :void
     {
-        _propSetFn(String(propName), value, -1);
+        _propSetFn(String(propName), value, -1, false);
     }
 
     override flash_proxy function deleteProperty (propName :*) :Boolean

src/as/com/threerings/ezgame/data/EZGameMarshaller.as

@@ -178,12 +178,12 @@ public class EZGameMarshaller extends InvocationMarshaller
     public static const SET_PROPERTY :int = 11;
 
     // from interface EZGameService
-    public function setProperty (arg1 :Client, arg2 :String, arg3 :Object, arg4 :int, arg5 :InvocationService_InvocationListener) :void
+    public function setProperty (arg1 :Client, arg2 :String, arg3 :Object, arg4 :int, arg5 :Boolean, arg6 :InvocationService_InvocationListener) :void
     {
-        var listener5 :InvocationMarshaller_ListenerMarshaller = new InvocationMarshaller_ListenerMarshaller();
-        listener5.listener = arg5;
+        var listener6 :InvocationMarshaller_ListenerMarshaller = new InvocationMarshaller_ListenerMarshaller();
+        listener6.listener = arg6;
         sendRequest(arg1, SET_PROPERTY, [
-            arg2, arg3, Integer.valueOf(arg4), listener5
+            arg2, arg3, Integer.valueOf(arg4), langBoolean.valueOf(arg5), listener6
         ]);
     }
 

src/as/com/threerings/ezgame/data/EZGameObject.as

@@ -98,26 +98,30 @@ public class EZGameObject extends GameObject
      * @return the old value
      */
     public function applyPropertySet (
-        propName :String, value :Object, index :int) :Object
+        propName :String, value :Object, index :int, testAndSet :Boolean)
+        :Object
     {
         var oldValue :Object = _props[propName];
-        if (index >= 0) {
-            // set an array element
-            var arr :Array = (oldValue as Array);
-            if (arr == null) {
-                arr = [];
-                _props[propName] = arr;
+        if ((testAndSet && oldValue == null) || ! testAndSet)
+        {
+            if (index >= 0) {
+                // set an array element
+                var arr :Array = (oldValue as Array);
+                if (arr == null) {
+                    arr = [];
+                    _props[propName] = arr;
+                }
+                oldValue = arr[index];
+                arr[index] = value;
+                
+            } else if (value != null) {
+                // normal property set
+                _props[propName] = value;
+                
+            } else {
+                // remove a property
+                delete _props[propName];
             }
-            oldValue = arr[index];
-            arr[index] = value;
-
-        } else if (value != null) {
-            // normal property set
-            _props[propName] = value;
-
-        } else {
-            // remove a property
-            delete _props[propName];
         }
         return oldValue;
     }

src/as/com/threerings/ezgame/data/PropertySetEvent.as

@@ -35,7 +35,7 @@ public class PropertySetEvent extends NamedEvent
     override public function applyToObject (target :DObject) :Boolean
     {
         _oldValue =
-            EZGameObject(target).applyPropertySet(_name, _data, _index);
+            EZGameObject(target).applyPropertySet(_name, _data, _index, _testAndSet);
         return true;
     }
 
@@ -69,6 +69,7 @@ public class PropertySetEvent extends NamedEvent
         super.readObject(ins);
         _index = ins.readInt();
         _data = EZObjectMarshaller.decode(ins.readObject());
+        _testAndSet = ins.readBoolean();
     }
 
     // from interface Streamable
@@ -77,6 +78,7 @@ public class PropertySetEvent extends NamedEvent
         super.writeObject(out);
         out.writeInt(_index);
         out.writeObject(_data);
+        out.writeBoolean(_testAndSet);
     }
 
     override protected function notifyListener (listener :Object) :void
@@ -99,6 +101,9 @@ public class PropertySetEvent extends NamedEvent
     /** The client-side data that is assigned to this property. */
     protected var _data :Object;
 
+    /** When true, the property will only be set if its previous value was null. */
+    protected var _testAndSet :Boolean;
+
     /** The old value. */
     protected var _oldValue :Object;
 }

src/java/com/threerings/ezgame/EZGame.java

@@ -27,6 +27,16 @@ public interface EZGame
      */
     public void set (String propName, Object value, int index);
 
+    /**
+     * Set a property that will be distributed. 
+     */
+    public void set (String propName, Object value, boolean testAndSet);
+
+    /**
+     * Set a property that will be distributed. 
+     */
+    public void set (String propName, Object value, int index, boolean testAndSet);
+
     /**
      * Register an object to receive whatever events it should receive,
      * based on which event listeners it implements. Note that it is not

src/java/com/threerings/ezgame/client/EZGameService.java

@@ -20,7 +20,7 @@ public interface EZGameService extends InvocationService
      */
     public void setProperty (
         Client client, String propName, Object value, int index,
-        InvocationListener listener);
+        boolean testAndSet, InvocationListener listener);
 
     /**
      * Request to end the turn, possibly futzing the next turn holder unless

src/java/com/threerings/ezgame/client/GameObjectImpl.java

@@ -61,22 +61,34 @@ public class GameObjectImpl
     // from EZGame
     public void set (String propName, Object value)
     {
-        set(propName, value, -1);
+        set(propName, value, -1, false);
+    }
+
+    // from EZGame
+    public void set (String propName, Object value, boolean testAndSet)
+    {
+        set(propName, value, -1, testAndSet);
     }
 
     // from EZGame
     public void set (String propName, Object value, int index)
+    {
+        set(propName, value, index, false);
+    }
+    
+    // from EZGame
+    public void set (String propName, Object value, int index, boolean testAndSet)
     {
         validatePropertyChange(propName, value, -1);
 
         Object encoded = EZObjectMarshaller.encode(value);
         Object reconstituted = EZObjectMarshaller.decode(encoded);
         _ezObj.ezGameService.setProperty(
-            _ctx.getClient(), propName, encoded, index,
+            _ctx.getClient(), propName, encoded, index, testAndSet,
             createLoggingListener("setProperty"));
 
         // set it immediately in the game object
-        _ezObj.applyPropertySet(propName, reconstituted, index);
+        _ezObj.applyPropertySet(propName, reconstituted, index, testAndSet);
     }
 
     // from EZGame

src/java/com/threerings/ezgame/data/EZGameMarshaller.java

@@ -171,12 +171,12 @@ public class EZGameMarshaller extends InvocationMarshaller
     public static final int SET_PROPERTY = 11;
 
     // from interface EZGameService
-    public void setProperty (Client arg1, String arg2, Object arg3, int arg4, InvocationService.InvocationListener arg5)
+    public void setProperty (Client arg1, String arg2, Object arg3, int arg4, boolean arg5, InvocationService.InvocationListener arg6)
     {
-        ListenerMarshaller listener5 = new ListenerMarshaller();
-        listener5.listener = arg5;
+        ListenerMarshaller listener6 = new ListenerMarshaller();
+        listener6.listener = arg6;
         sendRequest(arg1, SET_PROPERTY, new Object[] {
-            arg2, arg3, Integer.valueOf(arg4), listener5
+            arg2, arg3, Integer.valueOf(arg4), Boolean.valueOf(arg5), listener6
         });
     }
 

src/java/com/threerings/ezgame/data/EZGameObject.java

@@ -85,46 +85,50 @@ public class EZGameObject extends GameObject
     /**
      * Called by PropertySetEvent to effect the property update.
      */
-    public Object applyPropertySet (String propName, Object data, int index)
+    public Object applyPropertySet (
+        String propName, Object data, int index, boolean testAndSet)
     {
         Object oldValue = _props.get(propName);
-        if (index >= 0) {
-            if (isOnServer()) {
-                byte[][] arr = (oldValue instanceof byte[][])
-                    ? (byte[][]) oldValue : null;
-                if (arr == null || arr.length <= index) {
-                    // TODO: in case a user sets element 0 and element 90000,
-                    // we might want to store elements in a hash
-                    byte[][] newArr = new byte[index + 1][];
-                    if (arr != null) {
-                        System.arraycopy(arr, 0, newArr, 0, arr.length);
+        if ((testAndSet && oldValue == null) || ! testAndSet)
+        {
+            if (index >= 0) {
+                if (isOnServer()) {
+                    byte[][] arr = (oldValue instanceof byte[][])
+                        ? (byte[][]) oldValue : null;
+                    if (arr == null || arr.length <= index) {
+                        // TODO: in case a user sets element 0 and element 90000,
+                        // we might want to store elements in a hash
+                        byte[][] newArr = new byte[index + 1][];
+                        if (arr != null) {
+                            System.arraycopy(arr, 0, newArr, 0, arr.length);
+                        }
+                        _props.put(propName, newArr);
+                        arr = newArr;
                     }
-                    _props.put(propName, newArr);
-                    arr = newArr;
+                    oldValue = arr[index];
+                    arr[index] = (byte[]) data;
+
+                } else {
+                    Object[] arr = (oldValue instanceof Object[])
+                        ? (Object[]) oldValue : null;
+                    if (arr == null || arr.length <= index) {
+                        Object[] newArr = new Object[index + 1];
+                        if (arr != null) {
+                            System.arraycopy(arr, 0, newArr, 0, arr.length);
+                        }
+                        _props.put(propName, newArr);
+                        arr = newArr;
+                    }
+                    oldValue = arr[index];
+                    arr[index] = data;
                 }
-                oldValue = arr[index];
-                arr[index] = (byte[]) data;
+
+            } else if (data != null) {
+                _props.put(propName, data);
 
             } else {
-                Object[] arr = (oldValue instanceof Object[])
-                    ? (Object[]) oldValue : null;
-                if (arr == null || arr.length <= index) {
-                    Object[] newArr = new Object[index + 1];
-                    if (arr != null) {
-                        System.arraycopy(arr, 0, newArr, 0, arr.length);
-                    }
-                    _props.put(propName, newArr);
-                    arr = newArr;
-                }
-                oldValue = arr[index];
-                arr[index] = data;
+                _props.remove(propName);
             }
-
-        } else if (data != null) {
-            _props.put(propName, data);
-
-        } else {
-            _props.remove(propName);
         }
 
         return oldValue;

src/java/com/threerings/ezgame/data/PropertySetEvent.java

@@ -30,11 +30,12 @@ public class PropertySetEvent extends NamedEvent
      * Create a PropertySetEvent.
      */
     public PropertySetEvent (
-        int targetOid, String propName, Object value, int index)
+        int targetOid, String propName, Object value, int index, boolean testAndSet)
     {
         super(targetOid, propName);
         _data = value;
         _index = index;
+        _testAndSet = testAndSet;
     }
 
     /**
@@ -68,7 +69,7 @@ public class PropertySetEvent extends NamedEvent
         if (!ezObj.isOnServer()) {
             _data = EZObjectMarshaller.decode(_data);
         }
-        _oldValue = ezObj.applyPropertySet(_name, _data, _index);
+        _oldValue = ezObj.applyPropertySet(_name, _data, _index, _testAndSet);
         return true;
     }
 
@@ -94,6 +95,9 @@ public class PropertySetEvent extends NamedEvent
     /** The client-side data that is assigned to this property. */
     protected Object _data;
 
+    /** When true, the property will only be set if the old value was null. */
+    protected boolean _testAndSet;
+    
     /** The old value. */
     protected transient Object _oldValue;
 }

src/java/com/threerings/ezgame/server/DictionaryService.java

@@ -174,15 +174,6 @@ public class DictionaryService
     }
 
 
-    /**
-     * Obsolete init function. I'm keeping it around to prevent
-     * any automated build breakage between the upcoming Vilya checkin
-     * and the subsequent MSoy checkin. But this will go away real soon.
-     */
-    public static void init ()
-    {
-    }
-
     /**
      * Creates the singleton instance of the dictionary service.
      */

src/java/com/threerings/ezgame/server/EZGameDispatcher.java

@@ -129,7 +129,7 @@ public class EZGameDispatcher extends InvocationDispatcher
         case EZGameMarshaller.SET_PROPERTY:
             ((EZGameProvider)provider).setProperty(
                 source,
-                (String)args[0], (Object)args[1], ((Integer)args[2]).intValue(), (InvocationService.InvocationListener)args[3]
+                (String)args[0], (Object)args[1], ((Integer)args[2]).intValue(), ((Boolean)args[3]).booleanValue(), (InvocationService.InvocationListener)args[4]
             );
             return;
 

src/java/com/threerings/ezgame/server/EZGameManager.java

@@ -127,11 +127,11 @@ public class EZGameManager extends GameManager
     // from EZGameProvider
     public void setProperty (
         ClientObject caller, String propName, Object data, int index,
-        InvocationService.InvocationListener listener)
+        boolean testAndSet, InvocationService.InvocationListener listener)
         throws InvocationException
     {
         validateUser(caller);
-        setProperty(propName, data, index);
+        setProperty(propName, data, index, testAndSet);
     }
 
     // from EZGameProvider
@@ -220,7 +220,7 @@ public class EZGameManager extends GameManager
                 }
 
                 if (playerId == 0) {
-                    setProperty(msgOrPropName, result, -1);
+                    setProperty(msgOrPropName, result, -1, false);
                     
                 } else {
                     sendPrivateMessage(playerId, msgOrPropName, result);
@@ -400,10 +400,12 @@ public class EZGameManager extends GameManager
     /**
      * Helper method to post a property set event.
      */
-    protected void setProperty (String propName, Object value, int index)
+    protected void setProperty (
+        String propName, Object value, int index, boolean testAndSet)
     {
         _gameObj.postEvent(
-            new PropertySetEvent(_gameObj.getOid(), propName, value, index));
+            new PropertySetEvent(
+                _gameObj.getOid(), propName, value, index, testAndSet));
     }
 
     /**

src/java/com/threerings/ezgame/server/EZGameProvider.java

@@ -96,7 +96,7 @@ public interface EZGameProvider extends InvocationProvider
     /**
      * Handles a {@link EZGameService#setProperty} request.
      */
-    public void setProperty (ClientObject caller, String arg1, Object arg2, int arg3, InvocationService.InvocationListener arg4)
+    public void setProperty (ClientObject caller, String arg1, Object arg2, int arg3, boolean arg4, InvocationService.InvocationListener arg5)
         throws InvocationException;
 
     /**