// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// https://developers.google.com/protocol-buffers/
//
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package com.google.protobuf;

import static com.google.protobuf.Internal.checkNotNull;

import com.google.protobuf.Descriptors.Descriptor;
import com.google.protobuf.Descriptors.EnumValueDescriptor;
import com.google.protobuf.Descriptors.FieldDescriptor;
import com.google.protobuf.Descriptors.OneofDescriptor;
import java.io.IOException;
import java.io.InputStream;
import java.util.Collections;
import java.util.List;
import java.util.Map;

An implementation of Message that can represent arbitrary types, given a Descriptor. 
Author:
kenton@google.com Kenton Varda/**
 * An implementation of {@link Message} that can represent arbitrary types, given a {@link
 * Descriptors.Descriptor}.
 *
 * @author kenton@google.com Kenton Varda
 */
public final class DynamicMessage extends AbstractMessage {
  private final Descriptor type;
  private final FieldSet<FieldDescriptor> fields;
  private final FieldDescriptor[] oneofCases;
  private final UnknownFieldSet unknownFields;
  private int memoizedSize = -1;

  
Construct a DynamicMessage using the given FieldSet. oneofCases stores the FieldDescriptor for each oneof to indicate which field is set. Caller should make sure the array is immutable. 
This constructor is package private and will be used in DynamicMutableMessage to convert a mutable message to an immutable message. /**
   * Construct a {@code DynamicMessage} using the given {@code FieldSet}. oneofCases stores the
   * FieldDescriptor for each oneof to indicate which field is set. Caller should make sure the
   * array is immutable.
   *
   * <p>This constructor is package private and will be used in {@code DynamicMutableMessage} to
   * convert a mutable message to an immutable message.
   */
  DynamicMessage(
      Descriptor type,
      FieldSet<FieldDescriptor> fields,
      FieldDescriptor[] oneofCases,
      UnknownFieldSet unknownFields) {
    this.type = type;
    this.fields = fields;
    this.oneofCases = oneofCases;
    this.unknownFields = unknownFields;
  }

  
Get a DynamicMessage representing the default instance of the given type. /** Get a {@code DynamicMessage} representing the default instance of the given type. */
  public static DynamicMessage getDefaultInstance(Descriptor type) {
    int oneofDeclCount = type.toProto().getOneofDeclCount();
    FieldDescriptor[] oneofCases = new FieldDescriptor[oneofDeclCount];
    return new DynamicMessage(
        type,
        FieldSet.<FieldDescriptor>emptySet(),
        oneofCases,
        UnknownFieldSet.getDefaultInstance());
  }


  
Parse a message of the given type from the given input stream. /** Parse a message of the given type from the given input stream. */
  public static DynamicMessage parseFrom(Descriptor type, CodedInputStream input)
      throws IOException {
    return newBuilder(type).mergeFrom(input).buildParsed();
  }

  
Parse a message of the given type from the given input stream. /** Parse a message of the given type from the given input stream. */
  public static DynamicMessage parseFrom(
      Descriptor type, CodedInputStream input, ExtensionRegistry extensionRegistry)
      throws IOException {
    return newBuilder(type).mergeFrom(input, extensionRegistry).buildParsed();
  }

  
Parse data as a message of the given type and return it. /** Parse {@code data} as a message of the given type and return it. */
  public static DynamicMessage parseFrom(Descriptor type, ByteString data)
      throws InvalidProtocolBufferException {
    return newBuilder(type).mergeFrom(data).buildParsed();
  }

  
Parse data as a message of the given type and return it. /** Parse {@code data} as a message of the given type and return it. */
  public static DynamicMessage parseFrom(
      Descriptor type, ByteString data, ExtensionRegistry extensionRegistry)
      throws InvalidProtocolBufferException {
    return newBuilder(type).mergeFrom(data, extensionRegistry).buildParsed();
  }

  
Parse data as a message of the given type and return it. /** Parse {@code data} as a message of the given type and return it. */
  public static DynamicMessage parseFrom(Descriptor type, byte[] data)
      throws InvalidProtocolBufferException {
    return newBuilder(type).mergeFrom(data).buildParsed();
  }

  
Parse data as a message of the given type and return it. /** Parse {@code data} as a message of the given type and return it. */
  public static DynamicMessage parseFrom(
      Descriptor type, byte[] data, ExtensionRegistry extensionRegistry)
      throws InvalidProtocolBufferException {
    return newBuilder(type).mergeFrom(data, extensionRegistry).buildParsed();
  }

  
Parse a message of the given type from input and return it. /** Parse a message of the given type from {@code input} and return it. */
  public static DynamicMessage parseFrom(Descriptor type, InputStream input) throws IOException {
    return newBuilder(type).mergeFrom(input).buildParsed();
  }

  
Parse a message of the given type from input and return it. /** Parse a message of the given type from {@code input} and return it. */
  public static DynamicMessage parseFrom(
      Descriptor type, InputStream input, ExtensionRegistry extensionRegistry) throws IOException {
    return newBuilder(type).mergeFrom(input, extensionRegistry).buildParsed();
  }

  
Construct a Builder for the given type. /** Construct a {@link Message.Builder} for the given type. */
  public static Builder newBuilder(Descriptor type) {
    return new Builder(type);
  }

  
Construct a Builder for a message of the same type as prototype, and initialize it with prototype's contents. /**
   * Construct a {@link Message.Builder} for a message of the same type as {@code prototype}, and
   * initialize it with {@code prototype}'s contents.
   */
  public static Builder newBuilder(Message prototype) {
    return new Builder(prototype.getDescriptorForType()).mergeFrom(prototype);
  }

  // -----------------------------------------------------------------
  // Implementation of Message interface.

  @Override
  public Descriptor getDescriptorForType() {
    return type;
  }

  @Override
  public DynamicMessage getDefaultInstanceForType() {
    return getDefaultInstance(type);
  }

  @Override
  public Map<FieldDescriptor, Object> getAllFields() {
    return fields.getAllFields();
  }

  @Override
  public boolean hasOneof(OneofDescriptor oneof) {
    verifyOneofContainingType(oneof);
    FieldDescriptor field = oneofCases[oneof.getIndex()];
    if (field == null) {
      return false;
    }
    return true;
  }

  @Override
  public FieldDescriptor getOneofFieldDescriptor(OneofDescriptor oneof) {
    verifyOneofContainingType(oneof);
    return oneofCases[oneof.getIndex()];
  }

  @Override
  public boolean hasField(FieldDescriptor field) {
    verifyContainingType(field);
    return fields.hasField(field);
  }

  @Override
  public Object getField(FieldDescriptor field) {
    verifyContainingType(field);
    Object result = fields.getField(field);
    if (result == null) {
      if (field.isRepeated()) {
        result = Collections.emptyList();
      } else if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
        result = getDefaultInstance(field.getMessageType());
      } else {
        result = field.getDefaultValue();
      }
    }
    return result;
  }

  @Override
  public int getRepeatedFieldCount(FieldDescriptor field) {
    verifyContainingType(field);
    return fields.getRepeatedFieldCount(field);
  }

  @Override
  public Object getRepeatedField(FieldDescriptor field, int index) {
    verifyContainingType(field);
    return fields.getRepeatedField(field, index);
  }

  @Override
  public UnknownFieldSet getUnknownFields() {
    return unknownFields;
  }

  static boolean isInitialized(Descriptor type, FieldSet<FieldDescriptor> fields) {
    // Check that all required fields are present.
    for (final FieldDescriptor field : type.getFields()) {
      if (field.isRequired()) {
        if (!fields.hasField(field)) {
          return false;
        }
      }
    }

    // Check that embedded messages are initialized.
    return fields.isInitialized();
  }

  @Override
  public boolean isInitialized() {
    return isInitialized(type, fields);
  }

  @Override
  public void writeTo(CodedOutputStream output) throws IOException {
    if (type.getOptions().getMessageSetWireFormat()) {
      fields.writeMessageSetTo(output);
      unknownFields.writeAsMessageSetTo(output);
    } else {
      fields.writeTo(output);
      unknownFields.writeTo(output);
    }
  }

  @Override
  public int getSerializedSize() {
    int size = memoizedSize;
    if (size != -1) return size;

    if (type.getOptions().getMessageSetWireFormat()) {
      size = fields.getMessageSetSerializedSize();
      size += unknownFields.getSerializedSizeAsMessageSet();
    } else {
      size = fields.getSerializedSize();
      size += unknownFields.getSerializedSize();
    }

    memoizedSize = size;
    return size;
  }

  @Override
  public Builder newBuilderForType() {
    return new Builder(type);
  }

  @Override
  public Builder toBuilder() {
    return newBuilderForType().mergeFrom(this);
  }

  @Override
  public Parser<DynamicMessage> getParserForType() {
    return new AbstractParser<DynamicMessage>() {
      @Override
      public DynamicMessage parsePartialFrom(
          CodedInputStream input, ExtensionRegistryLite extensionRegistry)
          throws InvalidProtocolBufferException {
        Builder builder = newBuilder(type);
        try {
          builder.mergeFrom(input, extensionRegistry);
        } catch (InvalidProtocolBufferException e) {
          throw e.setUnfinishedMessage(builder.buildPartial());
        } catch (IOException e) {
          throw new InvalidProtocolBufferException(e).setUnfinishedMessage(builder.buildPartial());
        }
        return builder.buildPartial();
      }
    };
  }

  
Verifies that the field is a field of this message. /** Verifies that the field is a field of this message. */
  private void verifyContainingType(FieldDescriptor field) {
    if (field.getContainingType() != type) {
      throw new IllegalArgumentException("FieldDescriptor does not match message type.");
    }
  }

  
Verifies that the oneof is an oneof of this message. /** Verifies that the oneof is an oneof of this message. */
  private void verifyOneofContainingType(OneofDescriptor oneof) {
    if (oneof.getContainingType() != type) {
      throw new IllegalArgumentException("OneofDescriptor does not match message type.");
    }
  }

  // =================================================================

  
Builder for DynamicMessages. /** Builder for {@link DynamicMessage}s. */
  public static final class Builder extends AbstractMessage.Builder<Builder> {
    private final Descriptor type;
    private FieldSet<FieldDescriptor> fields;
    private final FieldDescriptor[] oneofCases;
    private UnknownFieldSet unknownFields;

    
Construct a Builder for the given type. /** Construct a {@code Builder} for the given type. */
    private Builder(Descriptor type) {
      this.type = type;
      this.fields = FieldSet.newFieldSet();
      this.unknownFields = UnknownFieldSet.getDefaultInstance();
      this.oneofCases = new FieldDescriptor[type.toProto().getOneofDeclCount()];
      // A MapEntry has all of its fields present at all times.
      if (type.getOptions().getMapEntry()) {
        populateMapEntry();
      }
    }

    private void populateMapEntry() {
      for (FieldDescriptor field : type.getFields()) {
        if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
          fields.setField(field, getDefaultInstance(field.getMessageType()));
        } else {
          fields.setField(field, field.getDefaultValue());
        }
      }
    }

    // ---------------------------------------------------------------
    // Implementation of Message.Builder interface.

    @Override
    public Builder clear() {
      if (fields.isImmutable()) {
        fields = FieldSet.newFieldSet();
      } else {
        fields.clear();
      }
      // A MapEntry has all of its fields present at all times.
      if (type.getOptions().getMapEntry()) {
        populateMapEntry();
      }
      unknownFields = UnknownFieldSet.getDefaultInstance();
      return this;
    }

    @Override
    public Builder mergeFrom(Message other) {
      if (other instanceof DynamicMessage) {
        // This should be somewhat faster than calling super.mergeFrom().
        DynamicMessage otherDynamicMessage = (DynamicMessage) other;
        if (otherDynamicMessage.type != type) {
          throw new IllegalArgumentException(
              "mergeFrom(Message) can only merge messages of the same type.");
        }
        ensureIsMutable();
        fields.mergeFrom(otherDynamicMessage.fields);
        mergeUnknownFields(otherDynamicMessage.unknownFields);
        for (int i = 0; i < oneofCases.length; i++) {
          if (oneofCases[i] == null) {
            oneofCases[i] = otherDynamicMessage.oneofCases[i];
          } else {
            if ((otherDynamicMessage.oneofCases[i] != null)
                && (oneofCases[i] != otherDynamicMessage.oneofCases[i])) {
              fields.clearField(oneofCases[i]);
              oneofCases[i] = otherDynamicMessage.oneofCases[i];
            }
          }
        }
        return this;
      } else {
        return super.mergeFrom(other);
      }
    }

    @Override
    public DynamicMessage build() {
      if (!isInitialized()) {
        throw newUninitializedMessageException(
            new DynamicMessage(
                type,
                fields,
                java.util.Arrays.copyOf(oneofCases, oneofCases.length),
                unknownFields));
      }
      return buildPartial();
    }

    
Helper for DynamicMessage.parseFrom() methods to call. Throws InvalidProtocolBufferException instead of UninitializedMessageException. /**
     * Helper for DynamicMessage.parseFrom() methods to call. Throws {@link
     * InvalidProtocolBufferException} instead of {@link UninitializedMessageException}.
     */
    private DynamicMessage buildParsed() throws InvalidProtocolBufferException {
      if (!isInitialized()) {
        throw newUninitializedMessageException(
                new DynamicMessage(
                    type,
                    fields,
                    java.util.Arrays.copyOf(oneofCases, oneofCases.length),
                    unknownFields))
            .asInvalidProtocolBufferException();
      }
      return buildPartial();
    }

    @Override
    public DynamicMessage buildPartial() {
      fields.makeImmutable();
      DynamicMessage result =
          new DynamicMessage(
              type, fields, java.util.Arrays.copyOf(oneofCases, oneofCases.length), unknownFields);
      return result;
    }

    @Override
    public Builder clone() {
      Builder result = new Builder(type);
      result.fields.mergeFrom(fields);
      result.mergeUnknownFields(unknownFields);
      System.arraycopy(oneofCases, 0, result.oneofCases, 0, oneofCases.length);
      return result;
    }

    @Override
    public boolean isInitialized() {
      return DynamicMessage.isInitialized(type, fields);
    }

    @Override
    public Descriptor getDescriptorForType() {
      return type;
    }

    @Override
    public DynamicMessage getDefaultInstanceForType() {
      return getDefaultInstance(type);
    }

    @Override
    public Map<FieldDescriptor, Object> getAllFields() {
      return fields.getAllFields();
    }

    @Override
    public Builder newBuilderForField(FieldDescriptor field) {
      verifyContainingType(field);

      if (field.getJavaType() != FieldDescriptor.JavaType.MESSAGE) {
        throw new IllegalArgumentException(
            "newBuilderForField is only valid for fields with message type.");
      }

      return new Builder(field.getMessageType());
    }

    @Override
    public boolean hasOneof(OneofDescriptor oneof) {
      verifyOneofContainingType(oneof);
      FieldDescriptor field = oneofCases[oneof.getIndex()];
      if (field == null) {
        return false;
      }
      return true;
    }

    @Override
    public FieldDescriptor getOneofFieldDescriptor(OneofDescriptor oneof) {
      verifyOneofContainingType(oneof);
      return oneofCases[oneof.getIndex()];
    }

    @Override
    public Builder clearOneof(OneofDescriptor oneof) {
      verifyOneofContainingType(oneof);
      FieldDescriptor field = oneofCases[oneof.getIndex()];
      if (field != null) {
        clearField(field);
      }
      return this;
    }

    @Override
    public boolean hasField(FieldDescriptor field) {
      verifyContainingType(field);
      return fields.hasField(field);
    }

    @Override
    public Object getField(FieldDescriptor field) {
      verifyContainingType(field);
      Object result = fields.getField(field);
      if (result == null) {
        if (field.isRepeated()) {
          result = Collections.emptyList();
        } else if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
          result = getDefaultInstance(field.getMessageType());
        } else {
          result = field.getDefaultValue();
        }
      }
      return result;
    }

    @Override
    public Builder setField(FieldDescriptor field, Object value) {
      verifyContainingType(field);
      ensureIsMutable();
      // TODO(xiaofeng): This check should really be put in FieldSet.setField()
      // where all other such checks are done. However, currently
      // FieldSet.setField() permits Integer value for enum fields probably
      // because of some internal features we support. Should figure it out
      // and move this check to a more appropriate place.
      if (field.getType() == FieldDescriptor.Type.ENUM) {
        ensureEnumValueDescriptor(field, value);
      }
      OneofDescriptor oneofDescriptor = field.getContainingOneof();
      if (oneofDescriptor != null) {
        int index = oneofDescriptor.getIndex();
        FieldDescriptor oldField = oneofCases[index];
        if ((oldField != null) && (oldField != field)) {
          fields.clearField(oldField);
        }
        oneofCases[index] = field;
      } else if (field.getFile().getSyntax() == Descriptors.FileDescriptor.Syntax.PROTO3) {
        if (!field.isRepeated()
            && field.getJavaType() != FieldDescriptor.JavaType.MESSAGE
            && value.equals(field.getDefaultValue())) {
          // In proto3, setting a field to its default value is equivalent to clearing the field.
          fields.clearField(field);
          return this;
        }
      }
      fields.setField(field, value);
      return this;
    }

    @Override
    public Builder clearField(FieldDescriptor field) {
      verifyContainingType(field);
      ensureIsMutable();
      OneofDescriptor oneofDescriptor = field.getContainingOneof();
      if (oneofDescriptor != null) {
        int index = oneofDescriptor.getIndex();
        if (oneofCases[index] == field) {
          oneofCases[index] = null;
        }
      }
      fields.clearField(field);
      return this;
    }

    @Override
    public int getRepeatedFieldCount(FieldDescriptor field) {
      verifyContainingType(field);
      return fields.getRepeatedFieldCount(field);
    }

    @Override
    public Object getRepeatedField(FieldDescriptor field, int index) {
      verifyContainingType(field);
      return fields.getRepeatedField(field, index);
    }

    @Override
    public Builder setRepeatedField(FieldDescriptor field, int index, Object value) {
      verifyContainingType(field);
      ensureIsMutable();
      fields.setRepeatedField(field, index, value);
      return this;
    }

    @Override
    public Builder addRepeatedField(FieldDescriptor field, Object value) {
      verifyContainingType(field);
      ensureIsMutable();
      fields.addRepeatedField(field, value);
      return this;
    }

    @Override
    public UnknownFieldSet getUnknownFields() {
      return unknownFields;
    }

    @Override
    public Builder setUnknownFields(UnknownFieldSet unknownFields) {
      this.unknownFields = unknownFields;
      return this;
    }

    @Override
    public Builder mergeUnknownFields(UnknownFieldSet unknownFields) {
      this.unknownFields =
          UnknownFieldSet.newBuilder(this.unknownFields).mergeFrom(unknownFields).build();
      return this;
    }

    
Verifies that the field is a field of this message. /** Verifies that the field is a field of this message. */
    private void verifyContainingType(FieldDescriptor field) {
      if (field.getContainingType() != type) {
        throw new IllegalArgumentException("FieldDescriptor does not match message type.");
      }
    }

    
Verifies that the oneof is an oneof of this message. /** Verifies that the oneof is an oneof of this message. */
    private void verifyOneofContainingType(OneofDescriptor oneof) {
      if (oneof.getContainingType() != type) {
        throw new IllegalArgumentException("OneofDescriptor does not match message type.");
      }
    }

    
Verifies that the value is EnumValueDescriptor and matches Enum Type. /** Verifies that the value is EnumValueDescriptor and matches Enum Type. */
    private void ensureSingularEnumValueDescriptor(FieldDescriptor field, Object value) {
      checkNotNull(value);
      if (!(value instanceof EnumValueDescriptor)) {
        throw new IllegalArgumentException(
            "DynamicMessage should use EnumValueDescriptor to set Enum Value.");
      }
      // TODO(xiaofeng): Re-enable this check after Orgstore is fixed to not
      // set incorrect EnumValueDescriptors.
      // EnumDescriptor fieldType = field.getEnumType();
      // EnumDescriptor fieldValueType = ((EnumValueDescriptor) value).getType();
      // if (fieldType != fieldValueType) {
      //  throw new IllegalArgumentException(String.format(
      //      "EnumDescriptor %s of field doesn't match EnumDescriptor %s of field value",
      //      fieldType.getFullName(), fieldValueType.getFullName()));
      // }
    }

    
Verifies the value for an enum field. /** Verifies the value for an enum field. */
    private void ensureEnumValueDescriptor(FieldDescriptor field, Object value) {
      if (field.isRepeated()) {
        for (Object item : (List) value) {
          ensureSingularEnumValueDescriptor(field, item);
        }
      } else {
        ensureSingularEnumValueDescriptor(field, value);
      }
    }

    private void ensureIsMutable() {
      if (fields.isImmutable()) {
        fields = fields.clone();
      }
    }

    @Override
    public com.google.protobuf.Message.Builder getFieldBuilder(FieldDescriptor field) {
      // TODO(xiangl): need implementation for dynamic message
      throw new UnsupportedOperationException(
          "getFieldBuilder() called on a dynamic message type.");
    }

    @Override
    public com.google.protobuf.Message.Builder getRepeatedFieldBuilder(
        FieldDescriptor field, int index) {
      throw new UnsupportedOperationException(
          "getRepeatedFieldBuilder() called on a dynamic message type.");
    }
  }
}