Allow scene updates to increment the version number by more than 1.

git-svn-id: svn+ssh://src.earth.threerings.net/vilya/trunk@572 c613c5cb-e716-0410-b11b-feb51c14d237

src/java/com/threerings/whirled/data/SceneUpdate.java

@@ -33,20 +33,18 @@ import com.threerings.util.ActionScript;
 import com.threerings.whirled.Log;
 
 /**
- * Used to encapsulate updates to scenes in such a manner that updates can
+ * Used to encapsulate updates to scenes in such a manner that updates can be stored persistently
- * be stored persistently and sent to clients to update their own local
+ * and sent to clients to update their own local copies of scenes.
- * copies of scenes.
  */
 public class SceneUpdate
     implements Streamable, Cloneable
 {
     /**
-     * Initializes this scene update such that it will operate on a scene
+     * Initializes this scene update such that it will operate on a scene with the specified target
-     * with the specified target scene and version number.
+     * scene and version number.
      *
      * @param targetId the id of the scene on which we are to operate.
-     * @param targetVersion the version of the scene on which we are to
+     * @param targetVersion the version of the scene on which we are to operate.
-     * operate.
      */
     public void init (int targetId, int targetVersion)
     {
@@ -71,43 +69,48 @@ public class SceneUpdate
     }
 
     /**
-     * Called to ensure that the scene is in the appropriate state prior
+     * Returns the amount by which this update increments the scene version.
-     * to applying the update.
+     */
+    public int getVersionIncrement ()
+    {
+        return 1;
+    }
+
+    /**
+     * Called to ensure that the scene is in the appropriate state prior to applying the update.
      *
-     * @exception IllegalStateException thrown if the update cannot be
+     * @exception IllegalStateException thrown if the update cannot be applied to the scene because
-     * applied to the scene because it is not in a valid state
+     * it is not in a valid state (appropriate previous updates were not applied, it's the wrong
-     * (appropriate previous updates were not applied, it's the wrong kind
+     * kind of scene, etc.).
-     * of scene, etc.).
      */
     public void validate (SceneModel model)
         throws IllegalStateException
     {
         if (model.sceneId != _targetId) {
-            String errmsg = "Wrong target scene, expected id " +
+            String errmsg = "Wrong target scene, expected id " + _targetId +
-                _targetId + " got id " + model.sceneId;
+                " got id " + model.sceneId;
             throw new IllegalStateException(errmsg);
         }
         if (model.version != _targetVersion) {
-            String errmsg = "Target scene not proper version, expected " +
+            String errmsg = "Target scene not proper version, expected " + _targetVersion +
-                _targetVersion + " got " + model.version;
+                " got " + model.version;
             throw new IllegalStateException(errmsg);
         }
     }
 
     /**
-     * Applies this update to the specified scene model. Derived classes
+     * Applies this update to the specified scene model. Derived classes will want to override this
-     * will want to override this method and apply updates of their own,
+     * method and apply updates of their own, being sure to call <code>super.apply</code>.
-     * being sure to call <code>super.apply</code>.
      */
     public void apply (SceneModel model)
     {
         // increment the version; disallowing integer overflow
-        model.version = Math.max(_targetVersion + 1, model.version);
+        model.version = Math.max(_targetVersion + getVersionIncrement(), model.version);
 
         // sanity check for the amazing two billion updates
         if (model.version == _targetVersion) {
-            Log.warning("Egads! This scene has been updated two billion " +
+            Log.warning("Egads! This scene has been updated two billion times [model=" + model +
-                        "times [model=" + model + ", update=" + this + "].");
+                        ", update=" + this + "].");
         }
     }
 
@@ -138,10 +141,9 @@ public class SceneUpdate
     }
 
     /**
-     * Serializes the bare representation of this instance without the scene id
+     * Serializes the bare representation of this instance without the scene id and version fields.
-     * and version fields.  Useful when storing updates in a database where the
+     * Useful when storing updates in a database where the scene id and version fields are stored
-     * scene id and version fields are stored in separate columns and the rest
+     * in separate columns and the rest if the representation is contained in an opaque blob.
-     * if the representation is contained in an opaque blob.
      */
     @ActionScript(omit=true)
     public void persistTo (ObjectOutputStream out)
@@ -156,8 +158,7 @@ public class SceneUpdate
     }
 
     /**
-     * Unserializes this instance from the bare representation created by
+     * Unserializes this instance from the bare representation created by {@link #persistTo}.
-     * {@link #persistTo}.
      */
     @ActionScript(omit=true)
     public void unpersistFrom (ObjectInputStream in)
@@ -182,8 +183,7 @@ public class SceneUpdate
     }
 
     /**
-     * An extensible mechanism for generating a string representation of
+     * An extensible mechanism for generating a string representation of this instance.
-     * this instance.
      */
     @ActionScript(name="toStringBuilder")
     protected void toString (StringBuilder buf)

src/java/com/threerings/whirled/server/SceneManager.java

@@ -149,8 +149,7 @@ public class SceneManager extends PlaceManager
         WhirledServer.invoker.postUnit(new Invoker.Unit() {
             public boolean invoke () {
                 try {
-                    _screg.getSceneRepository().applyAndRecordUpdate(
+                    _screg.getSceneRepository().applyAndRecordUpdate(_scene.getSceneModel(), update);
-                        _scene.getSceneModel(), update);
                 } catch (PersistenceException pe) {
                     Log.warning("Failed to apply scene update " + update + ".");
                     Log.logStackTrace(pe);

src/java/com/threerings/whirled/util/UpdateList.java

@@ -21,7 +21,9 @@
 
 package com.threerings.whirled.util;
 
-import java.util.ArrayList;
+import java.util.List;
+
+import com.google.common.collect.Lists;
 
 import com.threerings.whirled.Log;
 import com.threerings.whirled.data.SceneUpdate;
@@ -31,77 +33,66 @@ import com.threerings.whirled.data.SceneUpdate;
  */
 public class UpdateList
 {
-    public UpdateList ()
-    {
-        _updates = new ArrayList();
-    }
-
     /**
-     * Adds an update to this list. The update must follow appropriately
+     * Adds an update to this list. The update must follow appropriately the chain of updates
-     * the chain of updates established by the updates already in the list
+     * established by the updates already in the list (meaning it must operate on one version
-     * (meaning it must operate on one version higher than the most recent
+     * higher than the most recent update already in the list).
-     * update already in the list).
      */
     public void addUpdate (SceneUpdate update)
     {
-        if (_minVersion == -1) {
+        // if this is our first update, great, we let it in with no questions asked
-            // this is our first update, so we initialize our min version
+        if (_updates.isEmpty()) {
-            _minVersion = update.getSceneVersion();
+            _updates.add(update);
-
+            return;
-        } else {
-            int gotVersion = update.getSceneVersion();
-            int expVersion = _minVersion + _updates.size();
-            if (gotVersion > expVersion) {
-                Log.warning("Update continuity broken, flushing list " +
-                            "[got=" + update + ", expect=" + expVersion +
-                            ", ucount=" + _updates.size() + "].");
-                // flush out our old updates and start anew from here
-                _updates.clear();
-                _minVersion = expVersion;
-
-            } else if (gotVersion < expVersion) {
-                // we somehow got an update that's older than updates we
-                // already have? wick wick wack
-                String errmsg = "Invalid update version " +
-                    "[want=" + expVersion + ", got=" + update + "]";
-                throw new IllegalArgumentException(errmsg);
-            }
         }
+
+        // otherwise make sure this update conforms to our update sequence
+        SceneUpdate last = _updates.get(_updates.size()-1);
+        int expVersion = last.getSceneVersion() + last.getVersionIncrement();
+        int gotVersion = update.getSceneVersion();
+        if (gotVersion > expVersion) {
+            Log.warning("Update continuity broken, flushing list [got=" + update +
+                        ", expect=" + expVersion + ", ucount=" + _updates.size() + "].");
+            _updates.clear(); // flush out our old updates, fall through and add this one
+
+        } else if (gotVersion < expVersion) {
+            // we somehow got an update that's older than updates we already have?
+            String errmsg = "Invalid update version [want=" + expVersion + ", got=" + update + "]";
+            throw new IllegalArgumentException(errmsg);
+        }
+
         _updates.add(update);
     }
 
     /**
-     * Returns all of the updates that should be applied to a scene with
+     * Returns all of the updates that should be applied to a scene with the specified version to
-     * the specified version to bring it up to date. <code>null</code> is
+     * bring it up to date. <code>null</code> is returned if the scene's version is older than the
-     * returned if the scene's version is older than the oldest update in
+     * oldest update in our list, in which case it cannot be brought up to date by applying updates
-     * our list, in which case it cannot be brought up to date by applying
+     * from this list.
-     * updates from this list.
      */
     public SceneUpdate[] getUpdates (int fromVersion)
     {
-        if (_minVersion == -1 || fromVersion < _minVersion) {
+        List<SceneUpdate> updates = Lists.newArrayList();
-            return null;
+        for (SceneUpdate update : _updates) {
+            if (update.getSceneVersion() >= fromVersion) {
+                updates.add(update);
+            }
         }
-
+        return updates.toArray(new SceneUpdate[updates.size()]);
-        int offset = fromVersion - _minVersion;
-        int ucount = _updates.size() - offset;
-        SceneUpdate[] updates = new SceneUpdate[ucount];
-        for (int ii = 0; ii < ucount; ii++) {
-            updates[ii] = (SceneUpdate)_updates.get(ii+offset);
-        }
-        return updates;
     }
 
     /**
-     * Returns true if the supplied actual scene version is in accordance
+     * Returns true if the supplied actual scene version is in accordance with the updates
-     * with the updates contained in this list.
+     * contained in this list.
      */
     public boolean validate (int sceneVersion)
     {
-        return ((_minVersion == -1) || // we have no updates
+        if (_updates.size() == 0) {
-                (_minVersion + _updates.size() == sceneVersion));
+            return true;
+        }
+        SceneUpdate last = _updates.get(_updates.size()-1);
+        return sceneVersion == (last.getSceneVersion() + last.getVersionIncrement());
     }
 
-    protected ArrayList _updates;
+    protected List<SceneUpdate> _updates = Lists.newArrayList();
-    protected int _minVersion = -1;
 }