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.io.sstable;
  
  import java.nio.ByteBuffer;
  import java.nio.ByteOrder;
  import java.util.Objects;
  import java.util.function.Supplier;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  import java.util.stream.Stream;
  import javax.annotation.Nonnull;
  
  import com.google.common.base.Preconditions;
  
  import org.apache.cassandra.utils.TimeUUID;
  
  /**
   * SSTable generation identifiers that can be stored across nodes in one directory/bucket
   * <p>
   * Uses the UUID v1 identifiers
   */
  public final class UUIDBasedSSTableId implements SSTableId, Comparable<UUIDBasedSSTableId>
  {
      public final static int STRING_LEN = 28;
      public final static int BYTES_LEN = 16;
  
      private final TimeUUID uuid;
      private final String repr;
  
      public UUIDBasedSSTableId(TimeUUID uuid)
      {
          this.uuid = uuid;
          this.repr = asString();
      }
  
      @Override
      public ByteBuffer asBytes()
      {
          return ByteBuffer.allocate(16)
                           .order(ByteOrder.BIG_ENDIAN)
                           .putLong(0, uuid.uuidTimestamp())
                           .putLong(Long.BYTES, uuid.lsb());
      }
  
      private String asString()
      {
          long ts = uuid.uuidTimestamp();
          long nanoPart = ts % 10_000_000;
          ts = ts / 10_000_000;
          long seconds = ts % 86_400;
          ts = ts / 86_400;
  
          return String.format("%4s_%4s_%5s%13s",
                               Long.toString(ts, 36),
                               Long.toString(seconds, 36),
                               Long.toString(nanoPart, 36),
                               Long.toUnsignedString(uuid.lsb(), 36)).replace(' ', '0');
      }
  
      @Override
      public String toString()
      {
          return repr;
      }
  
      @Override
      public int compareTo(UUIDBasedSSTableId o)
      {
          if (o == null)
              return 1;
          else if (o == this)
              return 0;
  
          return uuid.compareTo(o.uuid);
      }
  
      @Override
      public boolean equals(Object o)
      {
  
          if (this == o) return true;
          if (o == null || getClass() != o.getClass())
              return false;
          UUIDBasedSSTableId that = (UUIDBasedSSTableId) o;
          return uuid.equals(that.uuid);
      }
  
      @Override
      public int hashCode()
      {
          return Objects.hash(uuid);
      }
  
      public static class Builder implements SSTableId.Builder<UUIDBasedSSTableId>
      {
          public static final Builder instance = new Builder();
          private final static Pattern PATTERN = Pattern.compile("([0-9a-z]{4})_([0-9a-z]{4})_([0-9a-z]{5})([0-9a-z]{13})", Pattern.CASE_INSENSITIVE);
  
          /**
           * Creates a new UUID based identifiers generator.
           *
           * @param existingIdentifiers not used by UUID based generator
           */
          @Override
          public Supplier<UUIDBasedSSTableId> generator(Stream<SSTableId> existingIdentifiers)
          {
              return () -> new UUIDBasedSSTableId(TimeUUID.Generator.nextTimeUUID());
          }
  
          @Override
          public boolean isUniqueIdentifier(String str)
          {
              return str != null && str.length() == STRING_LEN && PATTERN.matcher(str).matches();
          }
  
          @Override
          public boolean isUniqueIdentifier(ByteBuffer bytes)
          {
              return bytes != null && bytes.remaining() == BYTES_LEN;
          }
  
          @Override
          public UUIDBasedSSTableId fromString(@Nonnull String s) throws IllegalArgumentException
          {
              Matcher m = PATTERN.matcher(s);
              if (!m.matches())
                  throw new IllegalArgumentException("String '" + s + "' is not a valid UUID based sstable identifier");
  
              long dayPart = Long.parseLong(m.group(1), 36);
              long secondPart = Long.parseLong(m.group(2), 36);
              long nanoPart = Long.parseLong(m.group(3), 36);
              long ts = (dayPart * 86_400 + secondPart) * 10_000_000 + nanoPart;
              long randomPart = Long.parseUnsignedLong(m.group(4), 36);
  
              TimeUUID uuid = new TimeUUID(ts, randomPart);
              return new UUIDBasedSSTableId(uuid);
          }
  
          @Override
          public UUIDBasedSSTableId fromBytes(@Nonnull ByteBuffer bytes) throws IllegalArgumentException
          {
              Preconditions.checkArgument(bytes.remaining() == UUIDBasedSSTableId.BYTES_LEN, "Buffer does not have a valid number of bytes remaining. Expecting: %s but was: %s", UUIDBasedSSTableId.BYTES_LEN, bytes.remaining());
              bytes = bytes.order() == ByteOrder.BIG_ENDIAN ? bytes : bytes.duplicate().order(ByteOrder.BIG_ENDIAN);
              TimeUUID uuid = new TimeUUID(bytes.getLong(0), bytes.getLong(Long.BYTES));
              return new UUIDBasedSSTableId(uuid);
          }
      }
  }
  