content: // Protocol Buffers - Google's data interchange format
  // Copyright 2008 Google Inc.  All rights reserved.
  // https://developers.google.com/protocol-buffers/
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  //     * Redistributions of source code must retain the above copyright
  // notice, this list of conditions and the following disclaimer.
  //     * Redistributions in binary form must reproduce the above
  // copyright notice, this list of conditions and the following disclaimer
  // in the documentation and/or other materials provided with the
  // distribution.
  //     * Neither the name of Google Inc. nor the names of its
  // contributors may be used to endorse or promote products derived from
  // this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  package com.google.protobuf;
  
  import com.google.protobuf.AbstractMessageLite.Builder.LimitedInputStream;
  import com.google.protobuf.Internal.BooleanList;
  import com.google.protobuf.Internal.DoubleList;
  import com.google.protobuf.Internal.FloatList;
  import com.google.protobuf.Internal.IntList;
  import com.google.protobuf.Internal.LongList;
  import com.google.protobuf.Internal.ProtobufList;
  import com.google.protobuf.WireFormat.FieldType;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.ObjectStreamException;
  import java.io.Serializable;
  import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Method;
  import java.nio.ByteBuffer;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  /**
   * Lite version of {@link GeneratedMessage}.
   *
   * @author kenton@google.com Kenton Varda
   */
  public abstract class GeneratedMessageLite<
          MessageType extends GeneratedMessageLite<MessageType, BuilderType>,
          BuilderType extends GeneratedMessageLite.Builder<MessageType, BuilderType>>
      extends AbstractMessageLite<MessageType, BuilderType> {
  
    /** For use by generated code only. Lazily initialized to reduce allocations. */
    protected UnknownFieldSetLite unknownFields = UnknownFieldSetLite.getDefaultInstance();
  
    /** For use by generated code only. */
    protected int memoizedSerializedSize = -1;
  
    @Override
    @SuppressWarnings("unchecked") // Guaranteed by runtime.
    public final Parser<MessageType> getParserForType() {
      return (Parser<MessageType>) dynamicMethod(MethodToInvoke.GET_PARSER);
    }
  
    @Override
    @SuppressWarnings("unchecked") // Guaranteed by runtime.
    public final MessageType getDefaultInstanceForType() {
      return (MessageType) dynamicMethod(MethodToInvoke.GET_DEFAULT_INSTANCE);
    }
  
    @Override
    @SuppressWarnings("unchecked") // Guaranteed by runtime.
    public final BuilderType newBuilderForType() {
      return (BuilderType) dynamicMethod(MethodToInvoke.NEW_BUILDER);
    }
  
    /**
     * A reflective toString function. This is primarily intended as a developer aid, while keeping
     * binary size down. The first line of the {@code toString()} representation includes a commented
     * version of {@code super.toString()} to act as an indicator that this should not be relied on
     * for comparisons.
     *
     * <p>NOTE: This method relies on the field getter methods not being stripped or renamed by
     * proguard. If they are, the fields will not be included in the returned string representation.
     *
     * <p>NOTE: This implementation is liable to change in the future, and should not be relied on in
     * code.
     */
    @Override
    public String toString() {
      return MessageLiteToString.toString(this, super.toString());
    }
  
    @SuppressWarnings("unchecked") // Guaranteed by runtime
    @Override
    public int hashCode() {
      if (memoizedHashCode != 0) {
        return memoizedHashCode;
      }
      memoizedHashCode = Protobuf.getInstance().schemaFor(this).hashCode(this);
      return memoizedHashCode;
    }
  
    @SuppressWarnings("unchecked") // Guaranteed by isInstance + runtime
    @Override
    public boolean equals(Object other) {
      if (this == other) {
        return true;
      }
  
      if (!getDefaultInstanceForType().getClass().isInstance(other)) {
        return false;
      }
  
      return Protobuf.getInstance().schemaFor(this).equals(this, (MessageType) other);
    }
  
    // The general strategy for unknown fields is to use an UnknownFieldSetLite that is treated as
    // mutable during the parsing constructor and immutable after. This allows us to avoid
    // any unnecessary intermediary allocations while reducing the generated code size.
  
    /** Lazily initializes unknown fields. */
    private final void ensureUnknownFieldsInitialized() {
      if (unknownFields == UnknownFieldSetLite.getDefaultInstance()) {
        unknownFields = UnknownFieldSetLite.newInstance();
      }
    }
  
    /**
     * Called by subclasses to parse an unknown field. For use by generated code only.
     *
     * @return {@code true} unless the tag is an end-group tag.
     */
    protected boolean parseUnknownField(int tag, CodedInputStream input) throws IOException {
      // This will avoid the allocation of unknown fields when a group tag is encountered.
      if (WireFormat.getTagWireType(tag) == WireFormat.WIRETYPE_END_GROUP) {
        return false;
      }
  
      ensureUnknownFieldsInitialized();
      return unknownFields.mergeFieldFrom(tag, input);
    }
  
    /** Called by subclasses to parse an unknown field. For use by generated code only. */
    protected void mergeVarintField(int tag, int value) {
      ensureUnknownFieldsInitialized();
      unknownFields.mergeVarintField(tag, value);
    }
  
    /** Called by subclasses to parse an unknown field. For use by generated code only. */
    protected void mergeLengthDelimitedField(int fieldNumber, ByteString value) {
      ensureUnknownFieldsInitialized();
      unknownFields.mergeLengthDelimitedField(fieldNumber, value);
    }
  
    /** Called by subclasses to complete parsing. For use by generated code only. */
    protected void makeImmutable() {
      Protobuf.getInstance().schemaFor(this).makeImmutable(this);
    }
  
    protected final <
            MessageType extends GeneratedMessageLite<MessageType, BuilderType>,
            BuilderType extends GeneratedMessageLite.Builder<MessageType, BuilderType>>
        BuilderType createBuilder() {
      return (BuilderType) dynamicMethod(MethodToInvoke.NEW_BUILDER);
    }
  
    protected final <
            MessageType extends GeneratedMessageLite<MessageType, BuilderType>,
            BuilderType extends GeneratedMessageLite.Builder<MessageType, BuilderType>>
        BuilderType createBuilder(MessageType prototype) {
      return ((BuilderType) createBuilder()).mergeFrom(prototype);
    }
  
    @Override
    public final boolean isInitialized() {
      return isInitialized((MessageType) this, Boolean.TRUE);
    }
  
    @Override
    @SuppressWarnings("unchecked")
    public final BuilderType toBuilder() {
      BuilderType builder = (BuilderType) dynamicMethod(MethodToInvoke.NEW_BUILDER);
      builder.mergeFrom((MessageType) this);
      return builder;
    }
  
    /**
     * Defines which method path to invoke in {@link GeneratedMessageLite
     * #dynamicMethod(MethodToInvoke, Object...)}.
     *
     * <p>For use by generated code only.
     */
    public static enum MethodToInvoke {
      // Rely on/modify instance state
      GET_MEMOIZED_IS_INITIALIZED,
      SET_MEMOIZED_IS_INITIALIZED,
  
      // Rely on static state
      BUILD_MESSAGE_INFO,
      NEW_MUTABLE_INSTANCE,
      NEW_BUILDER,
      GET_DEFAULT_INSTANCE,
      GET_PARSER;
    }
  
    /**
     * A method that implements different types of operations described in {@link MethodToInvoke}.
     * Theses different kinds of operations are required to implement message-level operations for
     * builders in the runtime. This method bundles those operations to reduce the generated methods
     * count.
     *
     * <ul>
     *   <li>{@code NEW_INSTANCE} returns a new instance of the protocol buffer that has not yet been
     *       made immutable. See {@code MAKE_IMMUTABLE}.
     *   <li>{@code IS_INITIALIZED} returns {@code null} for false and the default instance for true.
     *       It doesn't use or modify any memoized value.
     *   <li>{@code GET_MEMOIZED_IS_INITIALIZED} returns the memoized {@code isInitialized} byte
     *       value.
     *   <li>{@code SET_MEMOIZED_IS_INITIALIZED} sets the memoized {@code isInitilaized} byte value to
     *       1 if the first parameter is not null, or to 0 if the first parameter is null.
     *   <li>{@code NEW_BUILDER} returns a {@code BuilderType} instance.
     * </ul>
     *
     * This method, plus the implementation of the Builder, enables the Builder class to be proguarded
     * away entirely on Android.
     *
     * <p>For use by generated code only.
     */
    protected abstract Object dynamicMethod(MethodToInvoke method, Object arg0, Object arg1);
  
    /** Same as {@link #dynamicMethod(MethodToInvoke, Object, Object)} with {@code null} padding. */
    protected Object dynamicMethod(MethodToInvoke method, Object arg0) {
      return dynamicMethod(method, arg0, null);
    }
  
    /** Same as {@link #dynamicMethod(MethodToInvoke, Object, Object)} with {@code null} padding. */
    protected Object dynamicMethod(MethodToInvoke method) {
      return dynamicMethod(method, null, null);
    }
  
    @Override
    int getMemoizedSerializedSize() {
      return memoizedSerializedSize;
    }
  
    @Override
    void setMemoizedSerializedSize(int size) {
      memoizedSerializedSize = size;
    }
  
    public void writeTo(CodedOutputStream output) throws IOException {
      writeToInternal(output);
    }
  
    public int getSerializedSize() {
      if (memoizedSerializedSize == -1) {
        memoizedSerializedSize = getSerializedSizeInternal();
      }
      return memoizedSerializedSize;
    }
  
    /** Constructs a {@link MessageInfo} for this message type. */
    Object buildMessageInfo() throws Exception {
      return dynamicMethod(MethodToInvoke.BUILD_MESSAGE_INFO);
    }
  
    private static Map<Object, GeneratedMessageLite<?, ?>> defaultInstanceMap =
        new ConcurrentHashMap<Object, GeneratedMessageLite<?, ?>>();
  
    @SuppressWarnings("unchecked")
    static <T extends GeneratedMessageLite<?, ?>> T getDefaultInstance(Class<T> clazz) {
      T result = (T) defaultInstanceMap.get(clazz);
      if (result == null) {
        // Foo.class does not initialize the class so we need to force the initialization in order to
        // get the default instance registered.
        try {
          Class.forName(clazz.getName(), true, clazz.getClassLoader());
        } catch (ClassNotFoundException e) {
          throw new IllegalStateException("Class initialization cannot fail.", e);
        }
        result = (T) defaultInstanceMap.get(clazz);
      }
      if (result == null) {
        // On some Samsung devices, this still doesn't return a valid value for some reason. We add a
        // reflective fallback to keep the device running. See b/114675342.
        result = (T) UnsafeUtil.allocateInstance(clazz).getDefaultInstanceForType();
        // A sanity check to ensure that <clinit> was actually invoked.
        if (result == null) {
          throw new IllegalStateException();
        }
        defaultInstanceMap.put(clazz, result);
      }
      return result;
    }
  
    protected static <T extends GeneratedMessageLite<?, ?>> void registerDefaultInstance(
        Class<T> clazz, T defaultInstance) {
      defaultInstanceMap.put(clazz, defaultInstance);
    }
  
    protected static Object newMessageInfo(
        MessageLite defaultInstance, String info, Object[] objects) {
      return new RawMessageInfo(defaultInstance, info, objects);
    }
  
    /**
     * Merge some unknown fields into the {@link UnknownFieldSetLite} for this message.
     *
     * <p>For use by generated code only.
     */
    protected final void mergeUnknownFields(UnknownFieldSetLite unknownFields) {
      this.unknownFields = UnknownFieldSetLite.mutableCopyOf(this.unknownFields, unknownFields);
    }
  
    @SuppressWarnings("unchecked")
    public abstract static class Builder<
            MessageType extends GeneratedMessageLite<MessageType, BuilderType>,
            BuilderType extends Builder<MessageType, BuilderType>>
        extends AbstractMessageLite.Builder<MessageType, BuilderType> {
  
      private final MessageType defaultInstance;
      protected MessageType instance;
      protected boolean isBuilt;
  
      protected Builder(MessageType defaultInstance) {
        this.defaultInstance = defaultInstance;
        this.instance =
            (MessageType) defaultInstance.dynamicMethod(MethodToInvoke.NEW_MUTABLE_INSTANCE);
        isBuilt = false;
      }
  
      /**
       * Called before any method that would mutate the builder to ensure that it correctly copies any
       * state before the write happens to preserve immutability guarantees.
       */
      protected void copyOnWrite() {
        if (isBuilt) {
          MessageType newInstance =
              (MessageType) instance.dynamicMethod(MethodToInvoke.NEW_MUTABLE_INSTANCE);
          mergeFromInstance(newInstance, instance);
          instance = newInstance;
          isBuilt = false;
        }
      }
  
      @Override
      public final boolean isInitialized() {
        return GeneratedMessageLite.isInitialized(instance, /* shouldMemoize= */ false);
      }
  
      @Override
      public final BuilderType clear() {
        // No need to copy on write since we're dropping the instance anyways.
        instance = (MessageType) instance.dynamicMethod(MethodToInvoke.NEW_MUTABLE_INSTANCE);
        return (BuilderType) this;
      }
  
      @Override
      public BuilderType clone() {
        BuilderType builder = (BuilderType) getDefaultInstanceForType().newBuilderForType();
        builder.mergeFrom(buildPartial());
        return builder;
      }
  
      @Override
      public MessageType buildPartial() {
        if (isBuilt) {
          return instance;
        }
  
        instance.makeImmutable();
  
        isBuilt = true;
        return instance;
      }
  
      @Override
      public final MessageType build() {
        MessageType result = buildPartial();
        if (!result.isInitialized()) {
          throw newUninitializedMessageException(result);
        }
        return result;
      }
  
      @Override
      protected BuilderType internalMergeFrom(MessageType message) {
        return mergeFrom(message);
      }
  
      /** All subclasses implement this. */
      public BuilderType mergeFrom(MessageType message) {
        copyOnWrite();
        mergeFromInstance(instance, message);
        return (BuilderType) this;
      }
  
      private void mergeFromInstance(MessageType dest, MessageType src) {
        Protobuf.getInstance().schemaFor(dest).mergeFrom(dest, src);
      }
  
      @Override
      public MessageType getDefaultInstanceForType() {
        return defaultInstance;
      }
  
      @Override
      public BuilderType mergeFrom(
          byte[] input, int offset, int length, ExtensionRegistryLite extensionRegistry)
          throws InvalidProtocolBufferException {
        copyOnWrite();
        try {
          Protobuf.getInstance().schemaFor(instance).mergeFrom(
              instance, input, offset, offset + length,
              new ArrayDecoders.Registers(extensionRegistry));
        } catch (InvalidProtocolBufferException e) {
          throw e;
        } catch (IndexOutOfBoundsException e) {
          throw InvalidProtocolBufferException.truncatedMessage();
        } catch (IOException e) {
          throw new RuntimeException("Reading from byte array should not throw IOException.", e);
        }
        return (BuilderType) this;
      }
  
      @Override
      public BuilderType mergeFrom(
          byte[] input, int offset, int length)
          throws InvalidProtocolBufferException {
        return mergeFrom(input, offset, length, ExtensionRegistryLite.getEmptyRegistry());
      }
  
      @Override
      public BuilderType mergeFrom(
          com.google.protobuf.CodedInputStream input,
          com.google.protobuf.ExtensionRegistryLite extensionRegistry)
          throws IOException {
        copyOnWrite();
        try {
          // TODO(yilunchong): Try to make input with type CodedInpuStream.ArrayDecoder use
          // fast path.
          Protobuf.getInstance().schemaFor(instance).mergeFrom(
              instance, CodedInputStreamReader.forCodedInput(input), extensionRegistry);
        } catch (RuntimeException e) {
          if (e.getCause() instanceof IOException) {
            throw (IOException) e.getCause();
          }
          throw e;
        }
        return (BuilderType) this;
      }
    }
  
  
    // =================================================================
    // Extensions-related stuff
  
    /** Lite equivalent of {@link com.google.protobuf.GeneratedMessage.ExtendableMessageOrBuilder}. */
    public interface ExtendableMessageOrBuilder<
            MessageType extends ExtendableMessage<MessageType, BuilderType>,
            BuilderType extends ExtendableBuilder<MessageType, BuilderType>>
        extends MessageLiteOrBuilder {
  
      /** Check if a singular extension is present. */
      <Type> boolean hasExtension(ExtensionLite<MessageType, Type> extension);
  
      /** Get the number of elements in a repeated extension. */
      <Type> int getExtensionCount(ExtensionLite<MessageType, List<Type>> extension);
  
      /** Get the value of an extension. */
      <Type> Type getExtension(ExtensionLite<MessageType, Type> extension);
  
      /** Get one element of a repeated extension. */
      <Type> Type getExtension(ExtensionLite<MessageType, List<Type>> extension, int index);
    }
  
    /** Lite equivalent of {@link GeneratedMessage.ExtendableMessage}. */
    public abstract static class ExtendableMessage<
            MessageType extends ExtendableMessage<MessageType, BuilderType>,
            BuilderType extends ExtendableBuilder<MessageType, BuilderType>>
        extends GeneratedMessageLite<MessageType, BuilderType>
        implements ExtendableMessageOrBuilder<MessageType, BuilderType> {
  
      /** Represents the set of extensions on this message. For use by generated code only. */
      protected FieldSet<ExtensionDescriptor> extensions = FieldSet.emptySet();
  
      @SuppressWarnings("unchecked")
      protected final void mergeExtensionFields(final MessageType other) {
        if (extensions.isImmutable()) {
          extensions = extensions.clone();
        }
        extensions.mergeFrom(((ExtendableMessage) other).extensions);
      }
  
      /**
       * Parse an unknown field or an extension. For use by generated code only.
       *
       * <p>For use by generated code only.
       *
       * @return {@code true} unless the tag is an end-group tag.
       */
      protected <MessageType extends MessageLite> boolean parseUnknownField(
          MessageType defaultInstance,
          CodedInputStream input,
          ExtensionRegistryLite extensionRegistry,
          int tag)
          throws IOException {
        int fieldNumber = WireFormat.getTagFieldNumber(tag);
  
        // TODO(dweis): How much bytecode would be saved by not requiring the generated code to
        //     provide the default instance?
        GeneratedExtension<MessageType, ?> extension =
            extensionRegistry.findLiteExtensionByNumber(defaultInstance, fieldNumber);
  
        return parseExtension(input, extensionRegistry, extension, tag, fieldNumber);
      }
  
      private boolean parseExtension(
          CodedInputStream input,
          ExtensionRegistryLite extensionRegistry,
          GeneratedExtension<?, ?> extension,
          int tag,
          int fieldNumber)
          throws IOException {
        int wireType = WireFormat.getTagWireType(tag);
        boolean unknown = false;
        boolean packed = false;
        if (extension == null) {
          unknown = true; // Unknown field.
        } else if (wireType
            == FieldSet.getWireFormatForFieldType(
                extension.descriptor.getLiteType(), /* isPacked= */ false)) {
          packed = false; // Normal, unpacked value.
        } else if (extension.descriptor.isRepeated
            && extension.descriptor.type.isPackable()
            && wireType
                == FieldSet.getWireFormatForFieldType(
                    extension.descriptor.getLiteType(), /* isPacked= */ true)) {
          packed = true; // Packed value.
        } else {
          unknown = true; // Wrong wire type.
        }
  
        if (unknown) { // Unknown field or wrong wire type.  Skip.
          return parseUnknownField(tag, input);
        }
  
        ensureExtensionsAreMutable();
  
        if (packed) {
          int length = input.readRawVarint32();
          int limit = input.pushLimit(length);
          if (extension.descriptor.getLiteType() == WireFormat.FieldType.ENUM) {
            while (input.getBytesUntilLimit() > 0) {
              int rawValue = input.readEnum();
              Object value = extension.descriptor.getEnumType().findValueByNumber(rawValue);
              if (value == null) {
                // If the number isn't recognized as a valid value for this
                // enum, drop it (don't even add it to unknownFields).
                return true;
              }
              extensions.addRepeatedField(
                  extension.descriptor, extension.singularToFieldSetType(value));
            }
          } else {
            while (input.getBytesUntilLimit() > 0) {
              Object value =
                  FieldSet.readPrimitiveField(
                      input, extension.descriptor.getLiteType(), /*checkUtf8=*/ false);
              extensions.addRepeatedField(extension.descriptor, value);
            }
          }
          input.popLimit(limit);
        } else {
          Object value;
          switch (extension.descriptor.getLiteJavaType()) {
            case MESSAGE:
              {
                MessageLite.Builder subBuilder = null;
                if (!extension.descriptor.isRepeated()) {
                  MessageLite existingValue = (MessageLite) extensions.getField(extension.descriptor);
                  if (existingValue != null) {
                    subBuilder = existingValue.toBuilder();
                  }
                }
                if (subBuilder == null) {
                  subBuilder = extension.getMessageDefaultInstance().newBuilderForType();
                }
                if (extension.descriptor.getLiteType() == WireFormat.FieldType.GROUP) {
                  input.readGroup(extension.getNumber(), subBuilder, extensionRegistry);
                } else {
                  input.readMessage(subBuilder, extensionRegistry);
                }
                value = subBuilder.build();
                break;
              }
            case ENUM:
              int rawValue = input.readEnum();
              value = extension.descriptor.getEnumType().findValueByNumber(rawValue);
              // If the number isn't recognized as a valid value for this enum,
              // write it to unknown fields object.
              if (value == null) {
                mergeVarintField(fieldNumber, rawValue);
                return true;
              }
              break;
            default:
              value =
                  FieldSet.readPrimitiveField(
                      input, extension.descriptor.getLiteType(), /*checkUtf8=*/ false);
              break;
          }
  
          if (extension.descriptor.isRepeated()) {
            extensions.addRepeatedField(
                extension.descriptor, extension.singularToFieldSetType(value));
          } else {
            extensions.setField(extension.descriptor, extension.singularToFieldSetType(value));
          }
        }
        return true;
      }
  
      /**
       * Parse an unknown field or an extension. For use by generated code only.
       *
       * <p>For use by generated code only.
       *
       * @return {@code true} unless the tag is an end-group tag.
       */
      protected <MessageType extends MessageLite> boolean parseUnknownFieldAsMessageSet(
          MessageType defaultInstance,
          CodedInputStream input,
          ExtensionRegistryLite extensionRegistry,
          int tag)
          throws IOException {
  
        if (tag == WireFormat.MESSAGE_SET_ITEM_TAG) {
          mergeMessageSetExtensionFromCodedStream(defaultInstance, input, extensionRegistry);
          return true;
        }
  
        // TODO(dweis): Do we really want to support non message set wire format in message sets?
        // Full runtime does... So we do for now.
        int wireType = WireFormat.getTagWireType(tag);
        if (wireType == WireFormat.WIRETYPE_LENGTH_DELIMITED) {
          return parseUnknownField(defaultInstance, input, extensionRegistry, tag);
        } else {
          // TODO(dweis): Should we throw on invalid input? Full runtime does not...
          return input.skipField(tag);
        }
      }
  
      /**
       * Merges the message set from the input stream; requires message set wire format.
       *
       * @param defaultInstance the default instance of the containing message we are parsing in
       * @param input the stream to parse from
       * @param extensionRegistry the registry to use when parsing
       */
      private <MessageType extends MessageLite> void mergeMessageSetExtensionFromCodedStream(
          MessageType defaultInstance,
          CodedInputStream input,
          ExtensionRegistryLite extensionRegistry)
          throws IOException {
        // The wire format for MessageSet is:
        //   message MessageSet {
        //     repeated group Item = 1 {
        //       required int32 typeId = 2;
        //       required bytes message = 3;
        //     }
        //   }
        // "typeId" is the extension's field number.  The extension can only be
        // a message type, where "message" contains the encoded bytes of that
        // message.
        //
        // In practice, we will probably never see a MessageSet item in which
        // the message appears before the type ID, or where either field does not
        // appear exactly once.  However, in theory such cases are valid, so we
        // should be prepared to accept them.
  
        int typeId = 0;
        ByteString rawBytes = null; // If we encounter "message" before "typeId"
        GeneratedExtension<?, ?> extension = null;
  
        // Read bytes from input, if we get it's type first then parse it eagerly,
        // otherwise we store the raw bytes in a local variable.
        while (true) {
          final int tag = input.readTag();
          if (tag == 0) {
            break;
          }
  
          if (tag == WireFormat.MESSAGE_SET_TYPE_ID_TAG) {
            typeId = input.readUInt32();
            if (typeId != 0) {
              extension = extensionRegistry.findLiteExtensionByNumber(defaultInstance, typeId);
            }
  
          } else if (tag == WireFormat.MESSAGE_SET_MESSAGE_TAG) {
            if (typeId != 0) {
              if (extension != null) {
                // We already know the type, so we can parse directly from the
                // input with no copying.  Hooray!
                eagerlyMergeMessageSetExtension(input, extension, extensionRegistry, typeId);
                rawBytes = null;
                continue;
              }
            }
            // We haven't seen a type ID yet or we want parse message lazily.
            rawBytes = input.readBytes();
  
          } else { // Unknown tag. Skip it.
            if (!input.skipField(tag)) {
              break; // End of group
            }
          }
        }
        input.checkLastTagWas(WireFormat.MESSAGE_SET_ITEM_END_TAG);
  
        // Process the raw bytes.
        if (rawBytes != null && typeId != 0) { // Zero is not a valid type ID.
          if (extension != null) { // We known the type
            mergeMessageSetExtensionFromBytes(rawBytes, extensionRegistry, extension);
          } else { // We don't know how to parse this. Ignore it.
            if (rawBytes != null) {
              mergeLengthDelimitedField(typeId, rawBytes);
            }
          }
        }
      }
  
      private void eagerlyMergeMessageSetExtension(
          CodedInputStream input,
          GeneratedExtension<?, ?> extension,
          ExtensionRegistryLite extensionRegistry,
          int typeId)
          throws IOException {
        int fieldNumber = typeId;
        int tag = WireFormat.makeTag(typeId, WireFormat.WIRETYPE_LENGTH_DELIMITED);
        parseExtension(input, extensionRegistry, extension, tag, fieldNumber);
      }
  
      private void mergeMessageSetExtensionFromBytes(
          ByteString rawBytes,
          ExtensionRegistryLite extensionRegistry,
          GeneratedExtension<?, ?> extension)
          throws IOException {
        MessageLite.Builder subBuilder = null;
        MessageLite existingValue = (MessageLite) extensions.getField(extension.descriptor);
        if (existingValue != null) {
          subBuilder = existingValue.toBuilder();
        }
        if (subBuilder == null) {
          subBuilder = extension.getMessageDefaultInstance().newBuilderForType();
        }
        subBuilder.mergeFrom(rawBytes, extensionRegistry);
        MessageLite value = subBuilder.build();
  
        ensureExtensionsAreMutable()
            .setField(extension.descriptor, extension.singularToFieldSetType(value));
      }
  
      FieldSet<ExtensionDescriptor> ensureExtensionsAreMutable() {
        if (extensions.isImmutable()) {
          extensions = extensions.clone();
        }
        return extensions;
      }
  
      private void verifyExtensionContainingType(final GeneratedExtension<MessageType, ?> extension) {
        if (extension.getContainingTypeDefaultInstance() != getDefaultInstanceForType()) {
          // This can only happen if someone uses unchecked operations.
          throw new IllegalArgumentException(
              "This extension is for a different message type.  Please make "
                  + "sure that you are not suppressing any generics type warnings.");
        }
      }
  
      /** Check if a singular extension is present. */
      @Override
      public final <Type> boolean hasExtension(final ExtensionLite<MessageType, Type> extension) {
        GeneratedExtension<MessageType, Type> extensionLite = checkIsLite(extension);
  
        verifyExtensionContainingType(extensionLite);
        return extensions.hasField(extensionLite.descriptor);
      }
  
      /** Get the number of elements in a repeated extension. */
      @Override
      public final <Type> int getExtensionCount(
          final ExtensionLite<MessageType, List<Type>> extension) {
        GeneratedExtension<MessageType, List<Type>> extensionLite = checkIsLite(extension);
  
        verifyExtensionContainingType(extensionLite);
        return extensions.getRepeatedFieldCount(extensionLite.descriptor);
      }
  
      /** Get the value of an extension. */
      @Override
      @SuppressWarnings("unchecked")
      public final <Type> Type getExtension(final ExtensionLite<MessageType, Type> extension) {
        GeneratedExtension<MessageType, Type> extensionLite = checkIsLite(extension);
  
        verifyExtensionContainingType(extensionLite);
        final Object value = extensions.getField(extensionLite.descriptor);
        if (value == null) {
          return extensionLite.defaultValue;
        } else {
          return (Type) extensionLite.fromFieldSetType(value);
        }
      }
  
      /** Get one element of a repeated extension. */
      @Override
      @SuppressWarnings("unchecked")
      public final <Type> Type getExtension(
          final ExtensionLite<MessageType, List<Type>> extension, final int index) {
        GeneratedExtension<MessageType, List<Type>> extensionLite = checkIsLite(extension);
  
        verifyExtensionContainingType(extensionLite);
        return (Type)
            extensionLite.singularFromFieldSetType(
                extensions.getRepeatedField(extensionLite.descriptor, index));
      }
  
      /** Called by subclasses to check if all extensions are initialized. */
      protected boolean extensionsAreInitialized() {
        return extensions.isInitialized();
      }
  
      /**
       * Used by subclasses to serialize extensions. Extension ranges may be interleaved with field
       * numbers, but we must write them in canonical (sorted by field number) order. ExtensionWriter
       * helps us write individual ranges of extensions at once.
       */
      protected class ExtensionWriter {
        // Imagine how much simpler this code would be if Java iterators had
        // a way to get the next element without advancing the iterator.
  
        private final Iterator<Map.Entry<ExtensionDescriptor, Object>> iter = extensions.iterator();
        private Map.Entry<ExtensionDescriptor, Object> next;
        private final boolean messageSetWireFormat;
  
        private ExtensionWriter(boolean messageSetWireFormat) {
          if (iter.hasNext()) {
            next = iter.next();
          }
          this.messageSetWireFormat = messageSetWireFormat;
        }
  
        public void writeUntil(final int end, final CodedOutputStream output) throws IOException {
          while (next != null && next.getKey().getNumber() < end) {
            ExtensionDescriptor extension = next.getKey();
            if (messageSetWireFormat
                && extension.getLiteJavaType() == WireFormat.JavaType.MESSAGE
                && !extension.isRepeated()) {
              output.writeMessageSetExtension(extension.getNumber(), (MessageLite) next.getValue());
            } else {
              FieldSet.writeField(extension, next.getValue(), output);
            }
            if (iter.hasNext()) {
              next = iter.next();
            } else {
              next = null;
            }
          }
        }
      }
  
      protected ExtensionWriter newExtensionWriter() {
        return new ExtensionWriter(false);
      }
  
      protected ExtensionWriter newMessageSetExtensionWriter() {
        return new ExtensionWriter(true);
      }
  
      /** Called by subclasses to compute the size of extensions. */
      protected int extensionsSerializedSize() {
        return extensions.getSerializedSize();
      }
  
      protected int extensionsSerializedSizeAsMessageSet() {
        return extensions.getMessageSetSerializedSize();
      }
    }
  
    /** Lite equivalent of {@link GeneratedMessage.ExtendableBuilder}. */
    @SuppressWarnings("unchecked")
    public abstract static class ExtendableBuilder<
            MessageType extends ExtendableMessage<MessageType, BuilderType>,
            BuilderType extends ExtendableBuilder<MessageType, BuilderType>>
        extends Builder<MessageType, BuilderType>
        implements ExtendableMessageOrBuilder<MessageType, BuilderType> {
      protected ExtendableBuilder(MessageType defaultInstance) {
        super(defaultInstance);
      }
  
      // For immutable message conversion.
      void internalSetExtensionSet(FieldSet<ExtensionDescriptor> extensions) {
        copyOnWrite();
        instance.extensions = extensions;
      }
  
      @Override
      protected void copyOnWrite() {
        if (!isBuilt) {
          return;
        }
  
        super.copyOnWrite();
        instance.extensions = instance.extensions.clone();
      }
  
      private FieldSet<ExtensionDescriptor> ensureExtensionsAreMutable() {
        FieldSet<ExtensionDescriptor> extensions = instance.extensions;
        if (extensions.isImmutable()) {
          extensions = extensions.clone();
          instance.extensions = extensions;
        }
        return extensions;
      }
  
      @Override
      public final MessageType buildPartial() {
        if (isBuilt) {
          return instance;
        }
  
        instance.extensions.makeImmutable();
        return super.buildPartial();
      }
  
      private void verifyExtensionContainingType(final GeneratedExtension<MessageType, ?> extension) {
        if (extension.getContainingTypeDefaultInstance() != getDefaultInstanceForType()) {
          // This can only happen if someone uses unchecked operations.
          throw new IllegalArgumentException(
              "This extension is for a different message type.  Please make "
                  + "sure that you are not suppressing any generics type warnings.");
        }
      }
  
      /** Check if a singular extension is present. */
      @Override
      public final <Type> boolean hasExtension(final ExtensionLite<MessageType, Type> extension) {
        return instance.hasExtension(extension);
      }
  
      /** Get the number of elements in a repeated extension. */
      @Override
      public final <Type> int getExtensionCount(
          final ExtensionLite<MessageType, List<Type>> extension) {
        return instance.getExtensionCount(extension);
      }
  
      /** Get the value of an extension. */
      @Override
      @SuppressWarnings("unchecked")
      public final <Type> Type getExtension(final ExtensionLite<MessageType, Type> extension) {
        return instance.getExtension(extension);
      }
  
      /** Get one element of a repeated extension. */
      @Override
      @SuppressWarnings("unchecked")
      public final <Type> Type getExtension(
          final ExtensionLite<MessageType, List<Type>> extension, final int index) {
        return instance.getExtension(extension, index);
      }
  
      /** Set the value of an extension. */
      public final <Type> BuilderType setExtension(
          final ExtensionLite<MessageType, Type> extension, final Type value) {
        GeneratedExtension<MessageType, Type> extensionLite = checkIsLite(extension);
  
        verifyExtensionContainingType(extensionLite);
        copyOnWrite();
        ensureExtensionsAreMutable()
            .setField(extensionLite.descriptor, extensionLite.toFieldSetType(value));
        return (BuilderType) this;
      }
  
      /** Set the value of one element of a repeated extension. */
      public final <Type> BuilderType setExtension(
          final ExtensionLite<MessageType, List<Type>> extension, final int index, final Type value) {
        GeneratedExtension<MessageType, List<Type>> extensionLite = checkIsLite(extension);
  
        verifyExtensionContainingType(extensionLite);
        copyOnWrite();
        ensureExtensionsAreMutable()
            .setRepeatedField(
                extensionLite.descriptor, index, extensionLite.singularToFieldSetType(value));
        return (BuilderType) this;
      }
  
      /** Append a value to a repeated extension. */
      public final <Type> BuilderType addExtension(
          final ExtensionLite<MessageType, List<Type>> extension, final Type value) {
        GeneratedExtension<MessageType, List<Type>> extensionLite = checkIsLite(extension);
  
        verifyExtensionContainingType(extensionLite);
        copyOnWrite();
        ensureExtensionsAreMutable()
            .addRepeatedField(extensionLite.descriptor, extensionLite.singularToFieldSetType(value));
        return (BuilderType) this;
      }
  
      /** Clear an extension. */
      public final <Type> BuilderType clearExtension(final ExtensionLite<MessageType, ?> extension) {
        GeneratedExtension<MessageType, ?> extensionLite = checkIsLite(extension);
  
        verifyExtensionContainingType(extensionLite);
        copyOnWrite();
        ensureExtensionsAreMutable().clearField(extensionLite.descriptor);
        return (BuilderType) this;
      }
    }
  
    // -----------------------------------------------------------------
  
    /** For use by generated code only. */
    public static <ContainingType extends MessageLite, Type>
        GeneratedExtension<ContainingType, Type> newSingularGeneratedExtension(
            final ContainingType containingTypeDefaultInstance,
            final Type defaultValue,
            final MessageLite messageDefaultInstance,
            final Internal.EnumLiteMap<?> enumTypeMap,
            final int number,
            final WireFormat.FieldType type,
            final Class singularType) {
      return new GeneratedExtension<ContainingType, Type>(
          containingTypeDefaultInstance,
          defaultValue,
          messageDefaultInstance,
          new ExtensionDescriptor(
              enumTypeMap, number, type, /* isRepeated= */ false, /* isPacked= */ false),
          singularType);
    }
  
    /** For use by generated code only. */
    public static <ContainingType extends MessageLite, Type>
        GeneratedExtension<ContainingType, Type> newRepeatedGeneratedExtension(
            final ContainingType containingTypeDefaultInstance,
            final MessageLite messageDefaultInstance,
            final Internal.EnumLiteMap<?> enumTypeMap,
            final int number,
            final WireFormat.FieldType type,
            final boolean isPacked,
            final Class singularType) {
      @SuppressWarnings("unchecked") // Subclasses ensure Type is a List
      Type emptyList = (Type) Collections.emptyList();
      return new GeneratedExtension<ContainingType, Type>(
          containingTypeDefaultInstance,
          emptyList,
          messageDefaultInstance,
          new ExtensionDescriptor(enumTypeMap, number, type, /* isRepeated= */ true, isPacked),
          singularType);
    }
  
    static final class ExtensionDescriptor
        implements FieldSet.FieldDescriptorLite<ExtensionDescriptor> {
      ExtensionDescriptor(
          final Internal.EnumLiteMap<?> enumTypeMap,
          final int number,
          final WireFormat.FieldType type,
          final boolean isRepeated,
          final boolean isPacked) {
        this.enumTypeMap = enumTypeMap;
        this.number = number;
        this.type = type;
        this.isRepeated = isRepeated;
        this.isPacked = isPacked;
      }
  
      final Internal.EnumLiteMap<?> enumTypeMap;
      final int number;
      final WireFormat.FieldType type;
      final boolean isRepeated;
      final boolean isPacked;
  
      @Override
      public int getNumber() {
        return number;
      }
  
      @Override
      public WireFormat.FieldType getLiteType() {
        return type;
      }
  
      @Override
      public WireFormat.JavaType getLiteJavaType() {
        return type.getJavaType();
      }
  
      @Override
      public boolean isRepeated() {
        return isRepeated;
      }
  
      @Override
      public boolean isPacked() {
        return isPacked;
      }
  
      @Override
      public Internal.EnumLiteMap<?> getEnumType() {
        return enumTypeMap;
      }
  
      @Override
      @SuppressWarnings("unchecked")
      public MessageLite.Builder internalMergeFrom(MessageLite.Builder to, MessageLite from) {
        return ((Builder) to).mergeFrom((GeneratedMessageLite) from);
      }
  
  
      @Override
      public int compareTo(ExtensionDescriptor other) {
        return number - other.number;
      }
    }
  
    // =================================================================
  
    /** Calls Class.getMethod and throws a RuntimeException if it fails. */
    @SuppressWarnings("unchecked")
    static Method getMethodOrDie(Class clazz, String name, Class... params) {
      try {
        return clazz.getMethod(name, params);
      } catch (NoSuchMethodException e) {
        throw new RuntimeException(
            "Generated message class \"" + clazz.getName() + "\" missing method \"" + name + "\".",
            e);
      }
    }
  
    /** Calls invoke and throws a RuntimeException if it fails. */
    static Object invokeOrDie(Method method, Object object, Object... params) {
      try {
        return method.invoke(object, params);
      } catch (IllegalAccessException e) {
        throw new RuntimeException(
            "Couldn't use Java reflection to implement protocol message reflection.", e);
      } catch (InvocationTargetException e) {
        final Throwable cause = e.getCause();
        if (cause instanceof RuntimeException) {
          throw (RuntimeException) cause;
        } else if (cause instanceof Error) {
          throw (Error) cause;
        } else {
          throw new RuntimeException(
              "Unexpected exception thrown by generated accessor method.", cause);
        }
      }
    }
  
  
    /**
     * Lite equivalent to {@link GeneratedMessage.GeneratedExtension}.
     *
     * <p>Users should ignore the contents of this class and only use objects of this type as
     * parameters to extension accessors and ExtensionRegistry.add().
     */
    public static class GeneratedExtension<ContainingType extends MessageLite, Type>
        extends ExtensionLite<ContainingType, Type> {
  
      /**
       * Create a new instance with the given parameters.
       *
       * <p>The last parameter {@code singularType} is only needed for enum types. We store integer
       * values for enum types in a {@link ExtendableMessage} and use Java reflection to convert an
       * integer value back into a concrete enum object.
       */
      GeneratedExtension(
          final ContainingType containingTypeDefaultInstance,
          final Type defaultValue,
          final MessageLite messageDefaultInstance,
          final ExtensionDescriptor descriptor,
          final Class singularType) {
        // Defensive checks to verify the correct initialization order of
        // GeneratedExtensions and their related GeneratedMessages.
        if (containingTypeDefaultInstance == null) {
          throw new IllegalArgumentException("Null containingTypeDefaultInstance");
        }
        if (descriptor.getLiteType() == WireFormat.FieldType.MESSAGE
            && messageDefaultInstance == null) {
          throw new IllegalArgumentException("Null messageDefaultInstance");
        }
        this.containingTypeDefaultInstance = containingTypeDefaultInstance;
        this.defaultValue = defaultValue;
        this.messageDefaultInstance = messageDefaultInstance;
        this.descriptor = descriptor;
      }
  
      final ContainingType containingTypeDefaultInstance;
      final Type defaultValue;
      final MessageLite messageDefaultInstance;
      final ExtensionDescriptor descriptor;
  
      /** Default instance of the type being extended, used to identify that type. */
      public ContainingType getContainingTypeDefaultInstance() {
        return containingTypeDefaultInstance;
      }
  
      /** Get the field number. */
      @Override
      public int getNumber() {
        return descriptor.getNumber();
      }
  
      /**
       * If the extension is an embedded message or group, returns the default instance of the
       * message.
       */
      @Override
      public MessageLite getMessageDefaultInstance() {
        return messageDefaultInstance;
      }
  
      @SuppressWarnings("unchecked")
      Object fromFieldSetType(final Object value) {
        if (descriptor.isRepeated()) {
          if (descriptor.getLiteJavaType() == WireFormat.JavaType.ENUM) {
            final List result = new ArrayList();
            for (final Object element : (List) value) {
              result.add(singularFromFieldSetType(element));
            }
            return result;
          } else {
            return value;
          }
        } else {
          return singularFromFieldSetType(value);
        }
      }
  
      Object singularFromFieldSetType(final Object value) {
        if (descriptor.getLiteJavaType() == WireFormat.JavaType.ENUM) {
          return descriptor.enumTypeMap.findValueByNumber((Integer) value);
        } else {
          return value;
        }
      }
  
      @SuppressWarnings("unchecked")
      Object toFieldSetType(final Object value) {
        if (descriptor.isRepeated()) {
          if (descriptor.getLiteJavaType() == WireFormat.JavaType.ENUM) {
            final List result = new ArrayList();
            for (final Object element : (List) value) {
              result.add(singularToFieldSetType(element));
            }
            return result;
          } else {
            return value;
          }
        } else {
          return singularToFieldSetType(value);
        }
      }
  
      Object singularToFieldSetType(final Object value) {
        if (descriptor.getLiteJavaType() == WireFormat.JavaType.ENUM) {
          return ((Internal.EnumLite) value).getNumber();
        } else {
          return value;
        }
      }
  
      @Override
      public FieldType getLiteType() {
        return descriptor.getLiteType();
      }
  
      @Override
      public boolean isRepeated() {
        return descriptor.isRepeated;
      }
  
      @Override
      public Type getDefaultValue() {
        return defaultValue;
      }
    }
  
    /**
     * A serialized (serializable) form of the generated message. Stores the message as a class name
     * and a byte array.
     */
    protected static final class SerializedForm implements Serializable {
  
      public static SerializedForm of(MessageLite message) {
        return new SerializedForm(message);
      }
  
      private static final long serialVersionUID = 0L;
  
      // since v3.6.1
      private final Class<?> messageClass;
      // only included for backwards compatibility before messageClass was added
      private final String messageClassName;
      private final byte[] asBytes;
  
      /**
       * Creates the serialized form by calling {@link com.google.protobuf.MessageLite#toByteArray}.
       *
       * @param regularForm the message to serialize
       */
      SerializedForm(MessageLite regularForm) {
        messageClass = regularForm.getClass();
        messageClassName = messageClass.getName();
        asBytes = regularForm.toByteArray();
      }
  
      /**
       * When read from an ObjectInputStream, this method converts this object back to the regular
       * form. Part of Java's serialization magic.
       *
       * @return a GeneratedMessage of the type that was serialized
       */
      @SuppressWarnings("unchecked")
      protected Object readResolve() throws ObjectStreamException {
        try {
          Class<?> messageClass = resolveMessageClass();
          java.lang.reflect.Field defaultInstanceField =
              messageClass.getDeclaredField("DEFAULT_INSTANCE");
          defaultInstanceField.setAccessible(true);
          MessageLite defaultInstance = (MessageLite) defaultInstanceField.get(null);
          return defaultInstance.newBuilderForType().mergeFrom(asBytes).buildPartial();
        } catch (ClassNotFoundException e) {
          throw new RuntimeException("Unable to find proto buffer class: " + messageClassName, e);
        } catch (NoSuchFieldException e) {
          return readResolveFallback();
        } catch (SecurityException e) {
          throw new RuntimeException("Unable to call DEFAULT_INSTANCE in " + messageClassName, e);
        } catch (IllegalAccessException e) {
          throw new RuntimeException("Unable to call parsePartialFrom", e);
        } catch (InvalidProtocolBufferException e) {
          throw new RuntimeException("Unable to understand proto buffer", e);
        }
      }
  
      /**
       * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1 generated code.
       */
      @Deprecated
      private Object readResolveFallback() throws ObjectStreamException {
        try {
          Class<?> messageClass = resolveMessageClass();
          java.lang.reflect.Field defaultInstanceField =
              messageClass.getDeclaredField("defaultInstance");
          defaultInstanceField.setAccessible(true);
          MessageLite defaultInstance = (MessageLite) defaultInstanceField.get(null);
          return defaultInstance.newBuilderForType()
              .mergeFrom(asBytes)
              .buildPartial();
        } catch (ClassNotFoundException e) {
          throw new RuntimeException("Unable to find proto buffer class: " + messageClassName, e);
        } catch (NoSuchFieldException e) {
          throw new RuntimeException("Unable to find defaultInstance in " + messageClassName, e);
        } catch (SecurityException e) {
          throw new RuntimeException("Unable to call defaultInstance in " + messageClassName, e);
        } catch (IllegalAccessException e) {
          throw new RuntimeException("Unable to call parsePartialFrom", e);
        } catch (InvalidProtocolBufferException e) {
          throw new RuntimeException("Unable to understand proto buffer", e);
        }
      }
  
      private Class<?> resolveMessageClass() throws ClassNotFoundException {
        return messageClass != null ? messageClass : Class.forName(messageClassName);
      }
    }
  
    /** Checks that the {@link Extension} is Lite and returns it as a {@link GeneratedExtension}. */
    private static <
            MessageType extends ExtendableMessage<MessageType, BuilderType>,
            BuilderType extends ExtendableBuilder<MessageType, BuilderType>,
            T>
        GeneratedExtension<MessageType, T> checkIsLite(ExtensionLite<MessageType, T> extension) {
      if (!extension.isLite()) {
        throw new IllegalArgumentException("Expected a lite extension.");
      }
  
      return (GeneratedExtension<MessageType, T>) extension;
    }
  
    /**
     * A static helper method for checking if a message is initialized, optionally memoizing.
     *
     * <p>For use by generated code only.
     */
    protected static final <T extends GeneratedMessageLite<T, ?>> boolean isInitialized(
        T message, boolean shouldMemoize) {
      byte memoizedIsInitialized =
          (Byte) message.dynamicMethod(MethodToInvoke.GET_MEMOIZED_IS_INITIALIZED);
      if (memoizedIsInitialized == 1) {
        return true;
      }
      if (memoizedIsInitialized == 0) {
        return false;
      }
      boolean isInitialized = Protobuf.getInstance().schemaFor(message).isInitialized(message);
      if (shouldMemoize) {
        message.dynamicMethod(
            MethodToInvoke.SET_MEMOIZED_IS_INITIALIZED, isInitialized ? message : null);
      }
      return isInitialized;
    }
  
    protected static IntList emptyIntList() {
      return IntArrayList.emptyList();
    }
  
    protected static IntList mutableCopy(IntList list) {
      int size = list.size();
      return list.mutableCopyWithCapacity(
          size == 0 ? AbstractProtobufList.DEFAULT_CAPACITY : size * 2);
    }
  
    protected static LongList emptyLongList() {
      return LongArrayList.emptyList();
    }
  
    protected static LongList mutableCopy(LongList list) {
      int size = list.size();
      return list.mutableCopyWithCapacity(
          size == 0 ? AbstractProtobufList.DEFAULT_CAPACITY : size * 2);
    }
  
    protected static FloatList emptyFloatList() {
      return FloatArrayList.emptyList();
    }
  
    protected static FloatList mutableCopy(FloatList list) {
      int size = list.size();
      return list.mutableCopyWithCapacity(
          size == 0 ? AbstractProtobufList.DEFAULT_CAPACITY : size * 2);
    }
  
    protected static DoubleList emptyDoubleList() {
      return DoubleArrayList.emptyList();
    }
  
    protected static DoubleList mutableCopy(DoubleList list) {
      int size = list.size();
      return list.mutableCopyWithCapacity(
          size == 0 ? AbstractProtobufList.DEFAULT_CAPACITY : size * 2);
    }
  
    protected static BooleanList emptyBooleanList() {
      return BooleanArrayList.emptyList();
    }
  
    protected static BooleanList mutableCopy(BooleanList list) {
      int size = list.size();
      return list.mutableCopyWithCapacity(
          size == 0 ? AbstractProtobufList.DEFAULT_CAPACITY : size * 2);
    }
  
    protected static <E> ProtobufList<E> emptyProtobufList() {
      return ProtobufArrayList.emptyList();
    }
  
    protected static <E> ProtobufList<E> mutableCopy(ProtobufList<E> list) {
      int size = list.size();
      return list.mutableCopyWithCapacity(
          size == 0 ? AbstractProtobufList.DEFAULT_CAPACITY : size * 2);
    }
  
    /**
     * A {@link Parser} implementation that delegates to the default instance.
     *
     * <p>For use by generated code only.
     */
    protected static class DefaultInstanceBasedParser<T extends GeneratedMessageLite<T, ?>>
        extends AbstractParser<T> {
  
      private final T defaultInstance;
  
      public DefaultInstanceBasedParser(T defaultInstance) {
        this.defaultInstance = defaultInstance;
      }
  
      @Override
      public T parsePartialFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry)
          throws InvalidProtocolBufferException {
        return GeneratedMessageLite.parsePartialFrom(defaultInstance, input, extensionRegistry);
      }
  
      @Override
      public T parsePartialFrom(
          byte[] input, int offset, int length, ExtensionRegistryLite extensionRegistry)
          throws InvalidProtocolBufferException {
        return GeneratedMessageLite.parsePartialFrom(
            defaultInstance, input, offset, length, extensionRegistry);
      }
    }
  
    /**
     * A static helper method for parsing a partial from input using the extension registry and the
     * instance.
     */
    // TODO(dweis): Should this verify that the last tag was 0?
    static <T extends GeneratedMessageLite<T, ?>> T parsePartialFrom(
        T instance, CodedInputStream input, ExtensionRegistryLite extensionRegistry)
        throws InvalidProtocolBufferException {
      @SuppressWarnings("unchecked") // Guaranteed by protoc
      T result = (T) instance.dynamicMethod(MethodToInvoke.NEW_MUTABLE_INSTANCE);
      try {
        // TODO(yilunchong): Try to make input with type CodedInpuStream.ArrayDecoder use
        // fast path.
        Protobuf.getInstance().schemaFor(result).mergeFrom(
            result, CodedInputStreamReader.forCodedInput(input), extensionRegistry);
        result.makeImmutable();
      } catch (IOException e) {
        if (e.getCause() instanceof InvalidProtocolBufferException) {
          throw (InvalidProtocolBufferException) e.getCause();
        }
        throw new InvalidProtocolBufferException(e.getMessage()).setUnfinishedMessage(result);
      } catch (RuntimeException e) {
        if (e.getCause() instanceof InvalidProtocolBufferException) {
          throw (InvalidProtocolBufferException) e.getCause();
        }
        throw e;
      }
      return result;
    }
  
    /** A static helper method for parsing a partial from byte array. */
    static <T extends GeneratedMessageLite<T, ?>> T parsePartialFrom(
        T instance, byte[] input, int offset, int length, ExtensionRegistryLite extensionRegistry)
        throws InvalidProtocolBufferException {
      @SuppressWarnings("unchecked") // Guaranteed by protoc
      T result = (T) instance.dynamicMethod(MethodToInvoke.NEW_MUTABLE_INSTANCE);
      try {
        Protobuf.getInstance().schemaFor(result).mergeFrom(
            result, input, offset, offset + length,
            new ArrayDecoders.Registers(extensionRegistry));
        result.makeImmutable();
        if (result.memoizedHashCode != 0) {
          throw new RuntimeException();
        }
      } catch (IOException e) {
        if (e.getCause() instanceof InvalidProtocolBufferException) {
          throw (InvalidProtocolBufferException) e.getCause();
        }
        throw new InvalidProtocolBufferException(e.getMessage()).setUnfinishedMessage(result);
      } catch (IndexOutOfBoundsException e) {
        throw InvalidProtocolBufferException.truncatedMessage().setUnfinishedMessage(result);
      }
      return result;
    }
  
    protected static <T extends GeneratedMessageLite<T, ?>> T parsePartialFrom(
        T defaultInstance, CodedInputStream input) throws InvalidProtocolBufferException {
      return parsePartialFrom(defaultInstance, input, ExtensionRegistryLite.getEmptyRegistry());
    }
  
    /**
     * Helper method to check if message is initialized.
     *
     * @throws InvalidProtocolBufferException if it is not initialized.
     * @return The message to check.
     */
    private static <T extends GeneratedMessageLite<T, ?>> T checkMessageInitialized(T message)
        throws InvalidProtocolBufferException {
      if (message != null && !message.isInitialized()) {
        throw message
            .newUninitializedMessageException()
            .asInvalidProtocolBufferException()
            .setUnfinishedMessage(message);
      }
      return message;
    }
  
    // Validates last tag.
    protected static <T extends GeneratedMessageLite<T, ?>> T parseFrom(
        T defaultInstance, ByteBuffer data, ExtensionRegistryLite extensionRegistry)
        throws InvalidProtocolBufferException {
      return checkMessageInitialized(
          parseFrom(defaultInstance, CodedInputStream.newInstance(data), extensionRegistry));
    }
  
    // Validates last tag.
    protected static <T extends GeneratedMessageLite<T, ?>> T parseFrom(
        T defaultInstance, ByteBuffer data) throws InvalidProtocolBufferException {
      return parseFrom(defaultInstance, data, ExtensionRegistryLite.getEmptyRegistry());
    }
  
    // Validates last tag.
    protected static <T extends GeneratedMessageLite<T, ?>> T parseFrom(
        T defaultInstance, ByteString data) throws InvalidProtocolBufferException {
      return checkMessageInitialized(
          parseFrom(defaultInstance, data, ExtensionRegistryLite.getEmptyRegistry()));
    }
  
    // Validates last tag.
    protected static <T extends GeneratedMessageLite<T, ?>> T parseFrom(
        T defaultInstance, ByteString data, ExtensionRegistryLite extensionRegistry)
        throws InvalidProtocolBufferException {
      return checkMessageInitialized(parsePartialFrom(defaultInstance, data, extensionRegistry));
    }
  
    // This is a special case since we want to verify that the last tag is 0. We assume we exhaust the
    // ByteString.
    private static <T extends GeneratedMessageLite<T, ?>> T parsePartialFrom(
        T defaultInstance, ByteString data, ExtensionRegistryLite extensionRegistry)
        throws InvalidProtocolBufferException {
      T message;
      try {
        CodedInputStream input = data.newCodedInput();
        message = parsePartialFrom(defaultInstance, input, extensionRegistry);
        try {
          input.checkLastTagWas(0);
        } catch (InvalidProtocolBufferException e) {
          throw e.setUnfinishedMessage(message);
        }
        return message;
      } catch (InvalidProtocolBufferException e) {
        throw e;
      }
    }
  
    // This is a special case since we want to verify that the last tag is 0. We assume we exhaust the
    // ByteString.
    private static <T extends GeneratedMessageLite<T, ?>> T parsePartialFrom(
        T defaultInstance, byte[] data, ExtensionRegistryLite extensionRegistry)
        throws InvalidProtocolBufferException {
      return checkMessageInitialized(
          parsePartialFrom(defaultInstance, data, 0, data.length, extensionRegistry));
    }
  
    // Validates last tag.
    protected static <T extends GeneratedMessageLite<T, ?>> T parseFrom(
        T defaultInstance, byte[] data) throws InvalidProtocolBufferException {
      return checkMessageInitialized(parsePartialFrom(
          defaultInstance, data, 0, data.length, ExtensionRegistryLite.getEmptyRegistry()));
    }
  
    // Validates last tag.
    protected static <T extends GeneratedMessageLite<T, ?>> T parseFrom(
        T defaultInstance, byte[] data, ExtensionRegistryLite extensionRegistry)
        throws InvalidProtocolBufferException {
      return checkMessageInitialized(
          parsePartialFrom(defaultInstance, data, 0, data.length, extensionRegistry));
    }
  
    // Does not validate last tag.
    protected static <T extends GeneratedMessageLite<T, ?>> T parseFrom(
        T defaultInstance, InputStream input) throws InvalidProtocolBufferException {
      return checkMessageInitialized(
          parsePartialFrom(
              defaultInstance,
              CodedInputStream.newInstance(input),
              ExtensionRegistryLite.getEmptyRegistry()));
    }
  
    // Does not validate last tag.
    protected static <T extends GeneratedMessageLite<T, ?>> T parseFrom(
        T defaultInstance, InputStream input, ExtensionRegistryLite extensionRegistry)
        throws InvalidProtocolBufferException {
      return checkMessageInitialized(
          parsePartialFrom(defaultInstance, CodedInputStream.newInstance(input), extensionRegistry));
    }
  
    // Does not validate last tag.
    protected static <T extends GeneratedMessageLite<T, ?>> T parseFrom(
        T defaultInstance, CodedInputStream input) throws InvalidProtocolBufferException {
      return parseFrom(defaultInstance, input, ExtensionRegistryLite.getEmptyRegistry());
    }
  
    // Does not validate last tag.
    protected static <T extends GeneratedMessageLite<T, ?>> T parseFrom(
        T defaultInstance, CodedInputStream input, ExtensionRegistryLite extensionRegistry)
        throws InvalidProtocolBufferException {
      return checkMessageInitialized(parsePartialFrom(defaultInstance, input, extensionRegistry));
    }
  
    // Validates last tag.
    protected static <T extends GeneratedMessageLite<T, ?>> T parseDelimitedFrom(
        T defaultInstance, InputStream input) throws InvalidProtocolBufferException {
      return checkMessageInitialized(
          parsePartialDelimitedFrom(
              defaultInstance, input, ExtensionRegistryLite.getEmptyRegistry()));
    }
  
    // Validates last tag.
    protected static <T extends GeneratedMessageLite<T, ?>> T parseDelimitedFrom(
        T defaultInstance, InputStream input, ExtensionRegistryLite extensionRegistry)
        throws InvalidProtocolBufferException {
      return checkMessageInitialized(
          parsePartialDelimitedFrom(defaultInstance, input, extensionRegistry));
    }
  
    private static <T extends GeneratedMessageLite<T, ?>> T parsePartialDelimitedFrom(
        T defaultInstance, InputStream input, ExtensionRegistryLite extensionRegistry)
        throws InvalidProtocolBufferException {
      int size;
      try {
        int firstByte = input.read();
        if (firstByte == -1) {
          return null;
        }
        size = CodedInputStream.readRawVarint32(firstByte, input);
      } catch (IOException e) {
        throw new InvalidProtocolBufferException(e.getMessage());
      }
      InputStream limitedInput = new LimitedInputStream(input, size);
      CodedInputStream codedInput = CodedInputStream.newInstance(limitedInput);
      T message = parsePartialFrom(defaultInstance, codedInput, extensionRegistry);
      try {
        codedInput.checkLastTagWas(0);
      } catch (InvalidProtocolBufferException e) {
        throw e.setUnfinishedMessage(message);
      }
      return message;
    }
  }
  