Down-integrate from internal code base.

3 files changed, 26 insertions, 22 deletions

diff --git a/java/src/main/java/com/google/protobuf/GeneratedMessageLite.java b/java/src/main/java/com/google/protobuf/GeneratedMessageLite.java
index 06492cc9..4d25c077 100644
--- a/java/src/main/java/com/google/protobuf/GeneratedMessageLite.java
+++ b/java/src/main/java/com/google/protobuf/GeneratedMessageLite.java
@@ -55,14 +55,6 @@ public abstract class GeneratedMessageLite extends AbstractMessageLite
   /** For use by generated code only.  */
   protected UnknownFieldSetLite unknownFields;
   
-  protected GeneratedMessageLite() {
-    unknownFields = UnknownFieldSetLite.getDefaultInstance();
-  }
-
-  protected GeneratedMessageLite(Builder builder) {
-    unknownFields = builder.unknownFields;
-  }
-
   public Parser<? extends MessageLite> getParserForType() {
     throw new UnsupportedOperationException(
         "This is supposed to be overridden by subclasses.");
@@ -87,7 +79,9 @@ public abstract class GeneratedMessageLite extends AbstractMessageLite
       extends AbstractMessageLite.Builder<BuilderType> {
 
     private final MessageType defaultInstance;
-    private UnknownFieldSetLite unknownFields =
+
+    /** For use by generated code only. */
+    protected UnknownFieldSetLite unknownFields =
         UnknownFieldSetLite.getDefaultInstance();
 
     protected Builder(MessageType defaultInstance) {
@@ -211,16 +205,8 @@ public abstract class GeneratedMessageLite extends AbstractMessageLite
      * Represents the set of extensions on this message. For use by generated
      * code only.
      */
-    protected final FieldSet<ExtensionDescriptor> extensions;
-
-    protected ExtendableMessage() {
-      this.extensions = FieldSet.newFieldSet();
-    }
-
-    protected ExtendableMessage(ExtendableBuilder<MessageType, ?> builder) {
-      this.extensions = builder.buildExtensions();
-    }
-
+    protected FieldSet<ExtensionDescriptor> extensions = FieldSet.newFieldSet();
+    
     private void verifyExtensionContainingType(
         final GeneratedExtension<MessageType, ?> extension) {
       if (extension.getContainingTypeDefaultInstance() !=
@@ -396,8 +382,10 @@ public abstract class GeneratedMessageLite extends AbstractMessageLite
     /**
      * Called by the build code path to create a copy of the extensions for
      * building the message.
+     * <p>
+     * For use by generated code only.
      */
-    private FieldSet<ExtensionDescriptor> buildExtensions() {
+    protected final FieldSet<ExtensionDescriptor> buildExtensions() {
       extensions.makeImmutable();
       extensionsIsMutable = false;
       return extensions;
@@ -472,8 +460,7 @@ public abstract class GeneratedMessageLite extends AbstractMessageLite
     // of this dummy clone() implementation makes it go away.
     @Override
     public BuilderType clone() {
-      throw new UnsupportedOperationException(
-          "This is supposed to be overridden by subclasses.");
+      return super.clone();
     }
     
     /** Set the value of an extension. */
diff --git a/java/src/main/java/com/google/protobuf/Internal.java b/java/src/main/java/com/google/protobuf/Internal.java
index ba0f526b..5ef39418 100644
--- a/java/src/main/java/com/google/protobuf/Internal.java
+++ b/java/src/main/java/com/google/protobuf/Internal.java
@@ -393,6 +393,10 @@ public class Internal {
    */
   public static final ByteBuffer EMPTY_BYTE_BUFFER =
       ByteBuffer.wrap(EMPTY_BYTE_ARRAY);
+  
+  /** An empty coded input stream constant used in generated code. */
+  public static final CodedInputStream EMPTY_CODED_INPUT_STREAM =
+      CodedInputStream.newInstance(EMPTY_BYTE_ARRAY);
 
 
   /**
diff --git a/java/src/test/java/com/google/protobuf/LiteTest.java b/java/src/test/java/com/google/protobuf/LiteTest.java
index 8bb30ad9..4d8037fc 100644
--- a/java/src/test/java/com/google/protobuf/LiteTest.java
+++ b/java/src/test/java/com/google/protobuf/LiteTest.java
@@ -145,4 +145,17 @@ public class LiteTest extends TestCase {
     assertEquals(expected.getOptionalNestedMessage().getBb(),
         actual.getOptionalNestedMessage().getBb());
   }
+  
+  public void testClone() {
+    TestAllTypesLite.Builder expected = TestAllTypesLite.newBuilder()
+        .setOptionalInt32(123);
+   assertEquals(
+       expected.getOptionalInt32(), expected.clone().getOptionalInt32());
+   
+   TestAllExtensionsLite.Builder expected2 = TestAllExtensionsLite.newBuilder()
+       .setExtension(UnittestLite.optionalInt32ExtensionLite, 123);
+   assertEquals(
+       expected2.getExtension(UnittestLite.optionalInt32ExtensionLite),
+       expected2.clone().getExtension(UnittestLite.optionalInt32ExtensionLite));
+  }
 }