path: root/java/src/main/java/com/google/protobuf/UnknownFieldSet.java

// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.
// http://code.google.com/p/protobuf/
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package com.google.protobuf;

import java.io.InputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.TreeMap;
import java.util.List;
import java.util.Map;

/**
 * {@code UnknownFieldSet} is used to keep track of fields which were seen when
 * parsing a protocol message but whose field numbers or types are unrecognized.
 * This most frequently occurs when new fields are added to a message type
 * and then messages containing those feilds are read by old software that was
 * compiled before the new types were added.
 *
 * <p>Every {@link Message} contains an {@code UnknownFieldSet} (and every
 * {@link Message.Builder} contains an {@link UnknownFieldSet.Builder}).
 *
 * <p>Most users will never need to use this class.
 *
 * @author kenton@google.com Kenton Varda
 */
public final class UnknownFieldSet {
  private UnknownFieldSet() {}

  /** Create a new {@link UnknownFieldSet.Builder}. */
  public static Builder newBuilder() {
    return new Builder();
  }

  /**
   * Create a new {@link UnknownFieldSet.Builder} and initialize it to be a copy
   * of {@code copyFrom}.
   */
  public static Builder newBuilder(UnknownFieldSet copyFrom) {
    return new Builder().mergeFrom(copyFrom);
  }

  /** Get an empty {@code UnknownFieldSet}. */
  public static UnknownFieldSet getDefaultInstance() {
    return defaultInstance;
  }
  private static UnknownFieldSet defaultInstance =
    new UnknownFieldSet(Collections.<Integer, Field>emptyMap());

  /**
   * Construct an {@code UnknownFieldSet} around the given map.  The map is
   * expected to be immutable.
   */
  private UnknownFieldSet(Map<Integer, Field> fields) {
    this.fields = fields;
  }
  private Map<Integer, Field> fields;

  /** Get a map of fields in the set by number. */
  public Map<Integer, Field> asMap() {
    return fields;
  }

  /** Check if the given field number is present in the set. */
  public boolean hasField(int number) {
    return fields.containsKey(number);
  }

  /**
   * Get a field by number.  Returns an empty field if not present.  Never
   * returns {@code null}.
   */
  public Field getField(int number) {
    Field result = fields.get(number);
    return (result == null) ? Field.getDefaultInstance() : result;
  }

  /** Serializes the set and writes it to {@code output}. */
  public void writeTo(CodedOutputStream output) throws IOException {
    for (Map.Entry<Integer, Field> entry : fields.entrySet()) {
      entry.getValue().writeTo(entry.getKey(), output);
    }
  }

  /**
   * Converts the set to a string in protocol buffer text format. This is
   * just a trivial wrapper around
   * {@link TextFormat#printToString(UnknownFieldSet)}.
   */
  public final String toString() {
    return TextFormat.printToString(this);
  }

  /**
   * Serializes the message to a {@code ByteString} and returns it. This is
   * just a trivial wrapper around {@link #writeTo(CodedOutputStream)}.
   */
  public final ByteString toByteString() {
    try {
      ByteString.CodedBuilder out =
        ByteString.newCodedBuilder(getSerializedSize());
      writeTo(out.getCodedOutput());
      return out.build();
    } catch (IOException e) {
      throw new RuntimeException(
        "Serializing to a ByteString threw an IOException (should " +
        "never happen).", e);
    }
  }

  /**
   * Serializes the message to a {@code byte} array and returns it.  This is
   * just a trivial wrapper around {@link #writeTo(CodedOutputStream)}.
   */
  public final byte[] toByteArray() {
    try {
      byte[] result = new byte[getSerializedSize()];
      CodedOutputStream output = CodedOutputStream.newInstance(result);
      writeTo(output);
      output.checkNoSpaceLeft();
      return result;
    } catch (IOException e) {
      throw new RuntimeException(
        "Serializing to a byte array threw an IOException " +
        "(should never happen).", e);
    }
  }

  /**
   * Serializes the message and writes it to {@code output}.  This is just a
   * trivial wrapper around {@link #writeTo(CodedOutputStream)}.
   */
  public final void writeTo(OutputStream output) throws IOException {
    CodedOutputStream codedOutput = CodedOutputStream.newInstance(output);
    writeTo(codedOutput);
    codedOutput.flush();
  }

  /** Get the number of bytes required to encode this set. */
  public int getSerializedSize() {
    int result = 0;
    for (Map.Entry<Integer, Field> entry : fields.entrySet()) {
      result += entry.getValue().getSerializedSize(entry.getKey());
    }
    return result;
  }

  /**
   * Serializes the set and writes it to {@code output} using
   * {@code MessageSet} wire format.
   */
  public void writeAsMessageSetTo(CodedOutputStream output)
      throws IOException {
    for (Map.Entry<Integer, Field> entry : fields.entrySet()) {
      entry.getValue().writeAsMessageSetExtensionTo(
        entry.getKey(), output);
    }
  }

  /**
   * Get the number of bytes required to encode this set using
   * {@code MessageSet} wire format.
   */
  public int getSerializedSizeAsMessageSet() {
    int result = 0;
    for (Map.Entry<Integer, Field> entry : fields.entrySet()) {
      result += entry.getValue().getSerializedSizeAsMessageSetExtension(
        entry.getKey());
    }
    return result;
  }

  /** Parse an {@code UnknownFieldSet} from the given input stream. */
  static public UnknownFieldSet parseFrom(CodedInputStream input)
                                          throws IOException {
    return newBuilder().mergeFrom(input).build();
  }

  /** Parse {@code data} as an {@code UnknownFieldSet} and return it. */
  public static UnknownFieldSet parseFrom(ByteString data)
      throws InvalidProtocolBufferException {
    return newBuilder().mergeFrom(data).build();
  }

  /** Parse {@code data} as an {@code UnknownFieldSet} and return it. */
  public static UnknownFieldSet parseFrom(byte[] data)
      throws InvalidProtocolBufferException {
    return newBuilder().mergeFrom(data).build();
  }

  /** Parse an {@code UnknownFieldSet} from {@code input} and return it. */
  public static UnknownFieldSet parseFrom(InputStream input)
                                          throws IOException {
    return newBuilder().mergeFrom(input).build();
  }

  /**
   * Builder for {@link UnknownFieldSet}s.
   *
   * <p>Note that this class maintains {@link Field.Builder}s for all fields
   * in the set.  Thus, adding one element to an existing {@link Field} does not
   * require making a copy.  This is important for efficient parsing of
   * unknown repeated fields.  However, it implies that {@link Field}s cannot
   * be constructed independently, nor can two {@link UnknownFieldSet}s share
   * the same {@code Field} object.
   *
   * <p>Use {@link UnknownFieldSet#newBuilder()} to construct a {@code Builder}.
   */
  public static final class Builder {
    private Builder() {}
    private Map<Integer, Field> fields = new TreeMap<Integer, Field>();

    // Optimization:  We keep around a builder for the last field that was
    //   modified so that we can efficiently add to it multiple times in a
    //   row (important when parsing an unknown repeated field).
    int lastFieldNumber = 0;
    Field.Builder lastField = null;

    /**
     * Get a field builder for the given field number which includes any
     * values that already exist.
     */
    private Field.Builder getFieldBuilder(int number) {
      if (lastField != null) {
        if (number == lastFieldNumber) {
          return lastField;
        }
        // Note:  addField() will reset lastField and lastFieldNumber.
        addField(lastFieldNumber, lastField.build());
      }
      if (number == 0) {
        return null;
      } else {
        Field existing = fields.get(number);
        lastFieldNumber = number;
        lastField = Field.newBuilder();
        if (existing != null) {
          lastField.mergeFrom(existing);
        }
        return lastField;
      }
    }

    /**
     * Build the {@link UnknownFieldSet} and return it.
     *
     * <p>Once {@code build()} has been called, the {@code Builder} will no
     * longer be usable.  Calling any method after {@code build()} will throw
     * {@code NullPointerException}.
     */
    public UnknownFieldSet build() {
      getFieldBuilder(0);  // Force lastField to be built.
      UnknownFieldSet result;
      if (fields.isEmpty()) {
        result = getDefaultInstance();
      } else {
        result = new UnknownFieldSet(Collections.unmodifiableMap(fields));
      }
      fields = null;
      return result;
    }

    /** Reset the builder to an empty set. */
    public Builder clear() {
      fields = new TreeMap<Integer, Field>();
      lastFieldNumber = 0;
      lastField = null;
      return this;
    }

    /**
     * Merge the fields from {@code other} into this set.  If a field number
     * exists in both sets, {@code other}'s values for that field will be
     * appended to the values in this set.
     */
    public Builder mergeFrom(UnknownFieldSet other) {
      if (other != getDefaultInstance()) {
        for (Map.Entry<Integer, Field> entry : other.fields.entrySet()) {
          mergeField(entry.getKey(), entry.getValue());
        }
      }
      return this;
    }

    /**
     * Add a field to the {@code UnknownFieldSet}.  If a field with the same
     * number already exists, the two are merged.
     */
    public Builder mergeField(int number, Field field) {
      if (number == 0) {
        throw new IllegalArgumentException("Zero is not a valid field number.");
      }
      if (hasField(number)) {
        getFieldBuilder(number).mergeFrom(field);
      } else {
        // Optimization:  We could call getFieldBuilder(number).mergeFrom(field)
        // in this case, but that would create a copy of the Field object.
        // We'd rather reuse the one passed to us, so call addField() instead.
        addField(number, field);
      }
      return this;
    }

    /**
     * Convenience method for merging a new field containing a single varint
     * value.  This is used in particular when an unknown enum value is
     * encountered.
     */
    public Builder mergeVarintField(int number, int value) {
      if (number == 0) {
        throw new IllegalArgumentException("Zero is not a valid field number.");
      }
      getFieldBuilder(number).addVarint(value);
      return this;
    }

    /** Check if the given field number is present in the set. */
    public boolean hasField(int number) {
      if (number == 0) {
        throw new IllegalArgumentException("Zero is not a valid field number.");
      }
      return number == lastFieldNumber || fields.containsKey(number);
    }

    /**
     * Add a field to the {@code UnknownFieldSet}.  If a field with the same
     * number already exists, it is removed.
     */
    public Builder addField(int number, Field field) {
      if (number == 0) {
        throw new IllegalArgumentException("Zero is not a valid field number.");
      }
      if (lastField != null && lastFieldNumber == number) {
        // Discard this.
        lastField = null;
        lastFieldNumber = 0;
      }
      fields.put(number, field);
      return this;
    }

    /**
     * Get all present {@code Field}s as an immutable {@code Map}.  If more
     * fields are added, the changes may or may not be reflected in this map.
     */
    public Map<Integer, Field> asMap() {
      getFieldBuilder(0);  // Force lastField to be built.
      return Collections.unmodifiableMap(fields);
    }

    /**
     * Parse an entire message from {@code input} and merge its fields into
     * this set.
     */
    public Builder mergeFrom(CodedInputStream input) throws IOException {
      while (true) {
        int tag = input.readTag();
        if (tag == 0 || !mergeFieldFrom(tag, input)) {
          break;
        }
      }
      return this;
    }

    /**
     * Parse a single field from {@code input} and merge it into this set.
     * @param tag The field's tag number, which was already parsed.
     * @return {@code false} if the tag is an engroup tag.
     */
    public boolean mergeFieldFrom(int tag, CodedInputStream input)
                                  throws IOException {
      int number = WireFormat.getTagFieldNumber(tag);
      switch (WireFormat.getTagWireType(tag)) {
        case WireFormat.WIRETYPE_VARINT:
          getFieldBuilder(number).addVarint(input.readInt32());
          return true;
        case WireFormat.WIRETYPE_FIXED64:
          getFieldBuilder(number).addFixed64(input.readFixed64());
          return true;
        case WireFormat.WIRETYPE_LENGTH_DELIMITED:
          getFieldBuilder(number).addLengthDelimited(input.readBytes());
          return true;
        case WireFormat.WIRETYPE_START_GROUP: {
          UnknownFieldSet.Builder subBuilder = UnknownFieldSet.newBuilder();
          input.readUnknownGroup(number, subBuilder);
          getFieldBuilder(number).addGroup(subBuilder.build());
          return true;
        }
        case WireFormat.WIRETYPE_END_GROUP:
          return false;
        case WireFormat.WIRETYPE_FIXED32:
          getFieldBuilder(number).addFixed32(input.readFixed32());
          return true;
        default:
          throw InvalidProtocolBufferException.invalidWireType();
      }
    }

    /**
     * Parse {@code data} as an {@code UnknownFieldSet} and merge it with the
     * set being built.  This is just a small wrapper around
     * {@link #mergeFrom(CodedInputStream)}.
     */
    public Builder mergeFrom(ByteString data)
        throws InvalidProtocolBufferException {
      try {
        CodedInputStream input = data.newCodedInput();
        mergeFrom(input);
        input.checkLastTagWas(0);
        return this;
      } catch (InvalidProtocolBufferException e) {
        throw e;
      } catch (IOException e) {
        throw new RuntimeException(
          "Reading from a ByteString threw an IOException (should " +
          "never happen).", e);
      }
    }

    /**
     * Parse {@code data} as an {@code UnknownFieldSet} and merge it with the
     * set being built.  This is just a small wrapper around
     * {@link #mergeFrom(CodedInputStream)}.
     */
    public Builder mergeFrom(byte[] data)
        throws InvalidProtocolBufferException {
      try {
        CodedInputStream input = CodedInputStream.newInstance(data);
        mergeFrom(input);
        input.checkLastTagWas(0);
        return this;
      } catch (InvalidProtocolBufferException e) {
        throw e;
      } catch (IOException e) {
        throw new RuntimeException(
          "Reading from a byte array threw an IOException (should " +
          "never happen).", e);
      }
    }

    /**
     * Parse an {@code UnknownFieldSet} from {@code input} and merge it with the
     * set being built.  This is just a small wrapper around
     * {@link #mergeFrom(CodedInputStream)}.
     */
    public Builder mergeFrom(InputStream input) throws IOException {
      CodedInputStream codedInput = CodedInputStream.newInstance(input);
      mergeFrom(codedInput);
      codedInput.checkLastTagWas(0);
      return this;
    }
  }

  /**
   * Represents a single field in an {@code UnknownFieldSet}.
   *
   * <p>A {@code Field} consists of five lists of values.  The lists correspond
   * to the five "wire types" used in the protocol buffer binary format.
   * The wire type of each field can be determined from the encoded form alone,
   * without knowing the field's declared type.  So, we are able to parse
   * unknown values at least this far and separate them.  Normally, only one
   * of the five lists will contain any values, since it is impossible to
   * define a valid message type that declares two different types for the
   * same field number.  However, the code is designed to allow for the case
   * where the same unknown field number is encountered using multiple different
   * wire types.
   *
   * <p>{@code Field} is an immutable class.  To construct one, you must use a
   * {@link Field.Builder}.
   *
   * @see UnknownFieldSet
   */
  public static final class Field {
    private Field() {}

    /** Construct a new {@link Builder}. */
    public static Builder newBuilder() {
      return new Builder();
    }

    /**
     * Construct a new {@link Builder} and initialize it to a copy of
     * {@code copyFrom}.
     */
    public static Builder newBuilder(Field copyFrom) {
      return new Builder().mergeFrom(copyFrom);
    }

    /** Get an empty {@code Field}. */
    public static Field getDefaultInstance() {
      return defaultInstance;
    }
    private static Field defaultInstance = newBuilder().build();

    /** Get the list of varint values for this field. */
    public List<Long> getVarintList()               { return varint;          }

    /** Get the list of fixed32 values for this field. */
    public List<Integer> getFixed32List()           { return fixed32;         }

    /** Get the list of fixed64 values for this field. */
    public List<Long> getFixed64List()              { return fixed64;         }

    /** Get the list of length-delimited values for this field. */
    public List<ByteString> getLengthDelimitedList() { return lengthDelimited; }

    /**
     * Get the list of embedded group values for this field.  These are
     * represented using {@link UnknownFieldSet}s rather than {@link Message}s
     * since the group's type is presumably unknown.
     */
    public List<UnknownFieldSet> getGroupList()      { return group;           }

    /**
     * Serializes the field, including field number, and writes it to
     * {@code output}.
     */
    public void writeTo(int fieldNumber, CodedOutputStream output)
                        throws IOException {
      for (long value : varint) {
        output.writeUInt64(fieldNumber, value);
      }
      for (int value : fixed32) {
        output.writeFixed32(fieldNumber, value);
      }
      for (long value : fixed64) {
        output.writeFixed64(fieldNumber, value);
      }
      for (ByteString value : lengthDelimited) {
        output.writeBytes(fieldNumber, value);
      }
      for (UnknownFieldSet value : group) {
        output.writeUnknownGroup(fieldNumber, value);
      }
    }

    /**
     * Get the number of bytes required to encode this field, including field
     * number.
     */
    public int getSerializedSize(int fieldNumber) {
      int result = 0;
      for (long value : varint) {
        result += CodedOutputStream.computeUInt64Size(fieldNumber, value);
      }
      for (int value : fixed32) {
        result += CodedOutputStream.computeFixed32Size(fieldNumber, value);
      }
      for (long value : fixed64) {
        result += CodedOutputStream.computeFixed64Size(fieldNumber, value);
      }
      for (ByteString value : lengthDelimited) {
        result += CodedOutputStream.computeBytesSize(fieldNumber, value);
      }
      for (UnknownFieldSet value : group) {
        result += CodedOutputStream.computeUnknownGroupSize(fieldNumber, value);
      }
      return result;
    }

    /**
     * Serializes the field, including field number, and writes it to
     * {@code output}, using {@code MessageSet} wire format.
     */
    public void writeAsMessageSetExtensionTo(
        int fieldNumber,
        CodedOutputStream output)
        throws IOException {
      for (ByteString value : lengthDelimited) {
        output.writeRawMessageSetExtension(fieldNumber, value);
      }
    }

    /**
     * Get the number of bytes required to encode this field, including field
     * number, using {@code MessageSet} wire format.
     */
    public int getSerializedSizeAsMessageSetExtension(int fieldNumber) {
      int result = 0;
      for (ByteString value : lengthDelimited) {
        result += CodedOutputStream.computeRawMessageSetExtensionSize(
          fieldNumber, value);
      }
      return result;
    }

    private List<Long> varint;
    private List<Integer> fixed32;
    private List<Long> fixed64;
    private List<ByteString> lengthDelimited;
    private List<UnknownFieldSet> group;

    /**
     * Used to build a {@link Field} within an {@link UnknownFieldSet}.
     *
     * <p>Use {@link Field#newBuilder()} to construct a {@code Builder}.
     */
    public static final class Builder {
      private Builder() {}
      private Field result = new Field();

      /**
       * Build the field.  After {@code build()} has been called, the
       * {@code Builder} is no longer usable.  Calling any other method will
       * throw a {@code NullPointerException}.
       */
      public Field build() {
        if (result.varint == null) {
          result.varint = Collections.emptyList();
        } else {
          result.varint = Collections.unmodifiableList(result.varint);
        }
        if (result.fixed32 == null) {
          result.fixed32 = Collections.emptyList();
        } else {
          result.fixed32 = Collections.unmodifiableList(result.fixed32);
        }
        if (result.fixed64 == null) {
          result.fixed64 = Collections.emptyList();
        } else {
          result.fixed64 = Collections.unmodifiableList(result.fixed64);
        }
        if (result.lengthDelimited == null) {
          result.lengthDelimited = Collections.emptyList();
        } else {
          result.lengthDelimited =
            Collections.unmodifiableList(result.lengthDelimited);
        }
        if (result.group == null) {
          result.group = Collections.emptyList();
        } else {
          result.group = Collections.unmodifiableList(result.group);
        }

        Field returnMe = result;
        result = null;
        return returnMe;
      }

      /** Discard the field's contents. */
      public Builder clear() {
        result = new Field();
        return this;
      }

      /**
       * Merge the values in {@code other} into this field.  For each list
       * of values, {@code other}'s values are append to the ones in this
       * field.
       */
      public Builder mergeFrom(Field other) {
        if (!other.varint.isEmpty()) {
          if (result.varint == null) {
            result.varint = new ArrayList<Long>();
          }
          result.varint.addAll(other.varint);
        }
        if (!other.fixed32.isEmpty()) {
          if (result.fixed32 == null) {
            result.fixed32 = new ArrayList<Integer>();
          }
          result.fixed32.addAll(other.fixed32);
        }
        if (!other.fixed64.isEmpty()) {
          if (result.fixed64 == null) {
            result.fixed64 = new ArrayList<Long>();
          }
          result.fixed64.addAll(other.fixed64);
        }
        if (!other.lengthDelimited.isEmpty()) {
          if (result.lengthDelimited == null) {
            result.lengthDelimited = new ArrayList<ByteString>();
          }
          result.lengthDelimited.addAll(other.lengthDelimited);
        }
        if (!other.group.isEmpty()) {
          if (result.group == null) {
            result.group = new ArrayList<UnknownFieldSet>();
          }
          result.group.addAll(other.group);
        }
        return this;
      }

      /** Add a varint value. */
      public Builder addVarint(long value) {
        if (result.varint == null) {
          result.varint = new ArrayList<Long>();
        }
        result.varint.add(value);
        return this;
      }

      /** Add a fixed32 value. */
      public Builder addFixed32(int value) {
        if (result.fixed32 == null) {
          result.fixed32 = new ArrayList<Integer>();
        }
        result.fixed32.add(value);
        return this;
      }

      /** Add a fixed64 value. */
      public Builder addFixed64(long value) {
        if (result.fixed64 == null) {
          result.fixed64 = new ArrayList<Long>();
        }
        result.fixed64.add(value);
        return this;
      }

      /** Add a length-delimited value. */
      public Builder addLengthDelimited(ByteString value) {
        if (result.lengthDelimited == null) {
          result.lengthDelimited = new ArrayList<ByteString>();
        }
        result.lengthDelimited.add(value);
        return this;
      }

      /** Add an embedded group. */
      public Builder addGroup(UnknownFieldSet value) {
        if (result.group == null) {
          result.group = new ArrayList<UnknownFieldSet>();
        }
        result.group.add(value);
        return this;
      }
    }
  }
}