Allow streaming Class references.

git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@5524 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/io/BasicStreamers.java

@@ -44,6 +44,7 @@ public class BasicStreamers
         Long.class,
         Float.class,
         Double.class,
+        Class.class,
         String.class,
         boolean[].class,
         byte[].class,
@@ -68,6 +69,7 @@ public class BasicStreamers
         new LongStreamer(),
         new FloatStreamer(),
         new DoubleStreamer(),
+        new ClassStreamer(),
         new StringStreamer(),
         new BooleanArrayStreamer(),
         new ByteArrayStreamer(),
@@ -225,6 +227,24 @@ public class BasicStreamers
         }
     }
 
+    /** Streams {@link Class} instances. */
+    public static class ClassStreamer extends BasicStreamer
+    {
+        @Override
+        public Object createObject (ObjectInputStream in)
+            throws IOException, ClassNotFoundException
+        {
+            return in.readClassMapping().sclass;
+        }
+
+        @Override
+        public void writeObject (Object object, ObjectOutputStream out, boolean useWriter)
+            throws IOException
+        {
+            out.writeClassMapping((Class)object);
+        }
+    }
+
     /** Streams {@link String} instances. */
     public static class StringStreamer extends BasicStreamer
     {

src/java/com/threerings/io/ObjectInputStream.java

@@ -76,8 +76,38 @@ public class ObjectInputStream extends DataInputStream
     public Object readObject ()
         throws IOException, ClassNotFoundException
     {
-        ClassMapping cmap;
+        try {
+            // read the class mapping
+            ClassMapping cmap = readClassMapping();
+            if (cmap == null) {
+                if (STREAM_DEBUG) {
+                    log.info(hashCode() + ": Read null.");
+                }
+                return null;
+            }
 
+            if (STREAM_DEBUG) {
+                log.info(hashCode() + ": Reading with " + cmap.streamer + ".");
+            }
+
+            // create an instance of the appropriate object
+            Object target = cmap.streamer.createObject(this);
+            readBareObject(target, cmap.streamer, true);
+            return target;
+
+        } catch (OutOfMemoryError oome) {
+            throw (IOException)new IOException("Malformed object data").initCause(oome);
+        }
+    }
+
+    /**
+     * Reads a class mapping from the stream.
+     *
+     * @return the class mapping, or <code>null</code> to represent a null value.
+     */
+    protected ClassMapping readClassMapping ()
+        throws IOException, ClassNotFoundException
+    {
         // create our classmap if necessary
         if (_classmap == null) {
             _classmap = new ArrayList<ClassMapping>();
@@ -85,15 +115,11 @@ public class ObjectInputStream extends DataInputStream
             _classmap.add(null);
         }
 
-        try {
         // read in the class code for this instance
         short code = readShort();
 
         // a zero code indicates a null value
         if (code == 0) {
-                if (STREAM_DEBUG) {
-                    log.info(hashCode() + ": Read null.");
-                }
             return null;
 
         // if the code is negative, that means that we've never seen it before and class
@@ -114,10 +140,10 @@ public class ObjectInputStream extends DataInputStream
             }
 
             // create the class mapping
-                cmap = mapClass(code, cname);
+            return mapClass(code, cname);
 
         } else {
-                cmap = _classmap.get(code);
+            ClassMapping cmap = _classmap.get(code);
 
             // sanity check
             if (cmap == null) {
@@ -129,19 +155,7 @@ public class ObjectInputStream extends DataInputStream
                     "metadata [code=" + code + "]";
                 throw new RuntimeException(errmsg);
             }
-            }
-
-            if (STREAM_DEBUG) {
-                log.info(hashCode() + ": Reading with " + cmap.streamer + ".");
-            }
-
-            // create an instance of the appropriate object
-            Object target = cmap.streamer.createObject(this);
-            readBareObject(target, cmap.streamer, true);
-            return target;
-
-        } catch (OutOfMemoryError oome) {
-            throw (IOException)new IOException("Malformed object data").initCause(oome);
+            return cmap;
         }
     }
 

src/java/com/threerings/io/ObjectOutputStream.java

@@ -71,13 +71,25 @@ public class ObjectOutputStream extends DataOutputStream
             return;
         }
 
+        // otherwise, write the class mapping, then the bare object
+        Class<?> sclass = Streamer.getStreamerClass(object);
+        ClassMapping cmap = writeClassMapping(sclass);
+        writeBareObject(object, cmap.streamer, true);
+    }
+
+    /**
+     * Retrieves or creates the class mapping for the supplied class, writes it out to the stream,
+     * and returns a reference to it.
+     */
+    protected ClassMapping writeClassMapping (Class<?> sclass)
+        throws IOException
+    {
         // create our classmap if necessary
         if (_classmap == null) {
             _classmap = new HashMap<Class<?>, ClassMapping>();
         }
 
-        // otherwise, look up the class mapping record
-        Class<?> sclass = Streamer.getStreamerClass(object);
+        // look up the class mapping record
         ClassMapping cmap = _classmap.get(sclass);
 
         // create a class mapping for this class if we've not got one
@@ -103,8 +115,7 @@ public class ObjectOutputStream extends DataOutputStream
         } else {
             writeExistingClassMapping(cmap);
         }
-
-        writeBareObject(object, cmap.streamer, true);
+        return cmap;
     }
 
     /**