Introduce FlattenedGeneratedMessageV3

protobuf-api/src/main/java/com/google/protobuf/AbstractMessageLite.java

@@ -248,62 +248,6 @@ public BuilderType mergeFrom(
       return (BuilderType) this;
     }
 
-    /**
-     * An InputStream implementations which reads from some other InputStream but is limited to a
-     * particular number of bytes. Used by mergeDelimitedFrom(). This is intentionally
-     * package-private so that UnknownFieldSet can share it.
-     */
-    static final class LimitedInputStream extends FilterInputStream {
-      private int limit;
-
-      LimitedInputStream(InputStream in, int limit) {
-        super(in);
-        this.limit = limit;
-      }
-
-      @Override
-      public int available() throws IOException {
-        return Math.min(super.available(), limit);
-      }
-
-      @Override
-      public int read() throws IOException {
-        if (limit <= 0) {
-          return -1;
-        }
-        final int result = super.read();
-        if (result >= 0) {
-          --limit;
-        }
-        return result;
-      }
-
-      @Override
-      public int read(final byte[] b, final int off, int len) throws IOException {
-        if (limit <= 0) {
-          return -1;
-        }
-        len = Math.min(len, limit);
-        final int result = super.read(b, off, len);
-        if (result >= 0) {
-          limit -= result;
-        }
-        return result;
-      }
-
-      @Override
-      public long skip(final long n) throws IOException {
-        // because we take the minimum of an int and a long, result is guaranteed to be
-        // less than or equal to Integer.MAX_INT so this cast is safe
-        int result = (int) super.skip(Math.min(n, limit));
-        if (result >= 0) {
-          // if the superclass adheres to the contract for skip, this condition is always true
-          limit -= result;
-        }
-        return result;
-      }
-    }
-
     @Override
     public boolean mergeDelimitedFrom(
         final InputStream input, final ExtensionRegistryLite extensionRegistry) throws IOException {

protobuf-api/src/main/java/com/google/protobuf/AbstractParser.java

@@ -7,7 +7,6 @@
 
 package com.google.protobuf;
 
-import com.google.protobuf.AbstractMessageLite.Builder.LimitedInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.ByteBuffer;

protobuf-api/src/main/java/com/google/protobuf/DynamicMessage.java

@@ -26,7 +26,7 @@
  *
  * @author [email protected] Kenton Varda
  */
-public final class DynamicMessage extends AbstractMessage {
+public final class DynamicMessage extends FlattenedAbstractMessage {
   private final Descriptor type;
   private final FieldSet<FieldDescriptor> fields;
   private final FieldDescriptor[] oneofCases;
@@ -293,7 +293,7 @@ private void verifyOneofContainingType(OneofDescriptor oneof) {
   // =================================================================
 
   /** Builder for {@link DynamicMessage}s. */
-  public static final class Builder extends AbstractMessage.Builder<Builder> {
+  public static final class Builder extends FlattenedAbstractMessage.Builder<Builder> {
     private final Descriptor type;
     private FieldSet.Builder<FieldDescriptor> fields;
     private final FieldDescriptor[] oneofCases;