content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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 org.apache.cassandra.db.marshal;
  
  import java.nio.ByteBuffer;
  import java.util.UUID;
  import java.util.regex.Pattern;
  
  import com.google.common.primitives.UnsignedLongs;
  
  import org.apache.cassandra.cql3.CQL3Type;
  import org.apache.cassandra.cql3.terms.Constants;
  import org.apache.cassandra.cql3.terms.Term;
  import org.apache.cassandra.cql3.functions.ArgumentDeserializer;
  import org.apache.cassandra.serializers.TypeSerializer;
  import org.apache.cassandra.serializers.MarshalException;
  import org.apache.cassandra.serializers.UUIDSerializer;
  import org.apache.cassandra.utils.ByteBufferUtil;
  import org.apache.cassandra.utils.bytecomparable.ByteComparable;
  import org.apache.cassandra.utils.bytecomparable.ByteSource;
  import org.apache.cassandra.utils.bytecomparable.ByteSourceInverse;
  import org.apache.cassandra.utils.UUIDGen;
  
  /**
   * Compares UUIDs using the following criteria:<br>
   * - if count of supplied bytes is less than 16, compare counts<br>
   * - compare UUID version fields<br>
   * - nil UUID is always lesser<br>
   * - compare timestamps if both are time-based<br>
   * - compare lexically, unsigned msb-to-lsb comparison<br>
   *
   * @see "com.fasterxml.uuid.UUIDComparator"
   */
  public class UUIDType extends AbstractType<UUID>
  {
      public static final UUIDType instance = new UUIDType();
  
      private static final ArgumentDeserializer ARGUMENT_DESERIALIZER = new DefaultArgumentDeserializer(instance);
  
      private static final ByteBuffer MASKED_VALUE = instance.decompose(UUID.fromString("00000000-0000-0000-0000-000000000000"));
  
      UUIDType()
      {
          super(ComparisonType.CUSTOM);
      }
  
      @Override
      public boolean allowsEmpty()
      {
          return true;
      }
  
      @Override
      public boolean isEmptyValueMeaningless()
      {
          return true;
      }
  
      public <VL, VR> int compareCustom(VL left, ValueAccessor<VL> accessorL, VR right, ValueAccessor<VR> accessorR)
      {
  
          // Compare for length
          boolean p1 = accessorL.size(left) == 16, p2 = accessorR.size(right) == 16;
          if (!(p1 & p2))
          {
              // should we assert exactly 16 bytes (or 0)? seems prudent
              assert p1 || accessorL.isEmpty(left);
              assert p2 || accessorR.isEmpty(right);
              return p1 ? 1 : p2 ? -1 : 0;
          }
  
          // Compare versions
          long msb1 = accessorL.getLong(left, 0);
          long msb2 = accessorR.getLong(right, 0);
  
          int version1 = (int) ((msb1 >>> 12) & 0xf);
          int version2 = (int) ((msb2 >>> 12) & 0xf);
          if (version1 != version2)
              return version1 - version2;
  
          // bytes: version is top 4 bits of byte 6
          // then: [6.5-8), [4-6), [0-4)
          if (version1 == 1)
          {
              long reorder1 = TimeUUIDType.reorderTimestampBytes(msb1);
              long reorder2 = TimeUUIDType.reorderTimestampBytes(msb2);
              // we know this is >= 0, since the top 3 bits will be 0
              int c = Long.compare(reorder1, reorder2);
              if (c != 0)
                  return c;
          }
          else
          {
              int c = UnsignedLongs.compare(msb1, msb2);
              if (c != 0)
                  return c;
          }
  
          // Amusingly (or not so much), although UUIDType freely takes time UUIDs (UUIDs with version 1), it compares
          // them differently than TimeUUIDType. This is evident in the least significant bytes comparison (the code
          // below for UUIDType), where UUIDType treats them as unsigned bytes, while TimeUUIDType compares the bytes
          // signed. See CASSANDRA-8730 for details around this discrepancy.
          return UnsignedLongs.compare(accessorL.getLong(left, 8), accessorR.getLong(right, 8));
      }
  
      @Override
      public <V> ByteSource asComparableBytes(ValueAccessor<V> accessor, V data, ByteComparable.Version v)
      {
          if (accessor.isEmpty(data))
              return null;
  
          long msb = accessor.getLong(data, 0);
          long version = ((msb >>> 12) & 0xf);
          ByteBuffer swizzled = ByteBuffer.allocate(16);
  
          if (version == 1)
              swizzled.putLong(0, TimeUUIDType.reorderTimestampBytes(msb));
          else
              swizzled.putLong(0, (version << 60) | ((msb >>> 4) & 0x0FFFFFFFFFFFF000L) | (msb & 0xFFFL));
  
          swizzled.putLong(8, accessor.getLong(data, 8));
  
          // fixed-length thus prefix-free
          return ByteSource.fixedLength(swizzled);
      }
  
      @Override
      public <V> V fromComparableBytes(ValueAccessor<V> accessor, ByteSource.Peekable comparableBytes, ByteComparable.Version version)
      {
          // Optional-style encoding of empty values as null sources
          if (comparableBytes == null)
              return accessor.empty();
  
          // The UUID bits are stored as an unsigned fixed-length 128-bit integer.
          long hiBits = ByteSourceInverse.getUnsignedFixedLengthAsLong(comparableBytes, 8);
          long loBits = ByteSourceInverse.getUnsignedFixedLengthAsLong(comparableBytes, 8);
  
          long uuidVersion = hiBits >>> 60 & 0xF;
          if (uuidVersion == 1)
          {
              // If the version bits are set to 1, this is a time-based UUID, and its high bits are significantly more
              // shuffled than in other UUIDs. Revert the shuffle.
              hiBits = TimeUUIDType.reorderBackTimestampBytes(hiBits);
          }
          else
          {
              // For non-time UUIDs, the only thing that's needed is to put the version bits back where they were originally.
              hiBits = hiBits << 4 & 0xFFFFFFFFFFFF0000L
                       | uuidVersion << 12
                       | hiBits & 0x0000000000000FFFL;
          }
  
          return makeUuidBytes(accessor, hiBits, loBits);
      }
  
      static <V> V makeUuidBytes(ValueAccessor<V> accessor, long high, long low)
      {
          V buffer = accessor.allocate(16);
          accessor.putLong(buffer, 0, high);
          accessor.putLong(buffer, 8, low);
          return buffer;
      }
  
      @Override
      public boolean isValueCompatibleWithInternal(AbstractType<?> otherType)
      {
          return otherType instanceof UUIDType || otherType instanceof TimeUUIDType;
      }
  
      @Override
      public ByteBuffer fromString(String source) throws MarshalException
      {
          // Return an empty ByteBuffer for an empty string.
          ByteBuffer parsed = parse(source);
          if (parsed != null)
              return parsed;
  
          throw new MarshalException(String.format("Unable to make UUID from '%s'", source));
      }
  
      @Override
      public CQL3Type asCQL3Type()
      {
          return CQL3Type.Native.UUID;
      }
  
      @Override
      public TypeSerializer<UUID> getSerializer()
      {
          return UUIDSerializer.instance;
      }
  
      @Override
      public ArgumentDeserializer getArgumentDeserializer()
      {
          return ARGUMENT_DESERIALIZER;
      }
  
      static final Pattern regexPattern = Pattern.compile("[A-Fa-f0-9]{8}\\-[A-Fa-f0-9]{4}\\-[A-Fa-f0-9]{4}\\-[A-Fa-f0-9]{4}\\-[A-Fa-f0-9]{12}");
  
      static ByteBuffer parse(String source)
      {
          if (source.isEmpty())
              return ByteBufferUtil.EMPTY_BYTE_BUFFER;
  
          if (regexPattern.matcher(source).matches())
          {
              try
              {
                  return UUIDGen.toByteBuffer(UUID.fromString(source));
              }
              catch (IllegalArgumentException e)
              {
                  throw new MarshalException(String.format("Unable to make UUID from '%s'", source), e);
              }
          }
  
          return null;
      }
  
      @Override
      public Term fromJSONObject(Object parsed) throws MarshalException
      {
          try
          {
              return new Constants.Value(fromString((String) parsed));
          }
          catch (ClassCastException exc)
          {
              throw new MarshalException(String.format(
                      "Expected a string representation of a uuid, but got a %s: %s", parsed.getClass().getSimpleName(), parsed));
          }
      }
  
      static int version(ByteBuffer uuid)
      {
          return (uuid.get(6) & 0xf0) >> 4;
      }
  
      @Override
      public int valueLengthIfFixed()
      {
          return 16;
      }
  
      @Override
      public ByteBuffer getMaskedValue()
      {
          return MASKED_VALUE;
      }
  }
  