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.fqltool;
  
  
  import java.nio.ByteBuffer;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Objects;
  import java.util.function.Supplier;
  import java.util.stream.Collectors;
  
  import com.google.common.collect.AbstractIterator;
  
  import net.openhft.chronicle.queue.ExcerptTailer;
  import org.apache.cassandra.utils.ByteBufferUtil;
  import org.apache.cassandra.utils.Pair;
  
  /**
   * represents a resultset defined by the format in ResultStore on disk
   *
   * todo: Currently all iterators need to be consumed fully while iterating over result sets
   *       if this is created from a tailer. This can probably be improved, but for all current uses it is fine.
   */
  public class StoredResultSet implements ResultHandler.ComparableResultSet
  {
      private final ResultHandler.ComparableColumnDefinitions defs;
      public final boolean hasMoreResultSets;
      private final Supplier<Iterator<ResultHandler.ComparableRow>> rowIteratorSupplier;
      private final boolean wasFailed;
      private final Throwable failureException;
  
      /**
       * create a new StoredResultSet
       *
       * note that we use an iteratorSupplier to be able to iterate over the same in-memory rows several times *in tests*
       */
      public StoredResultSet(ResultHandler.ComparableColumnDefinitions defs,
                             boolean hasMoreResultSets,
                             boolean wasFailed,
                             Throwable failure,
                             Supplier<Iterator<ResultHandler.ComparableRow>> iteratorSupplier)
      {
          this.defs = defs;
          this.hasMoreResultSets = hasMoreResultSets;
          this.wasFailed = wasFailed;
          this.failureException = failure;
          this.rowIteratorSupplier = iteratorSupplier;
      }
  
      /**
       * creates a ComparableResultSet based on the data in tailer
       */
      public static StoredResultSet fromTailer(ExcerptTailer tailer)
      {
          ResultStore.ColumnDefsReader reader = new ResultStore.ColumnDefsReader();
          boolean hasMoreResultSets = tailer.readDocument(reader);
          ResultHandler.ComparableColumnDefinitions defs = new StoredComparableColumnDefinitions(reader.columnDefinitions,
                                                                                                 reader.wasFailed,
                                                                                                 new RuntimeException(reader.failureMessage));
  
  
          Iterator<ResultHandler.ComparableRow> rowIterator = new AbstractIterator<ResultHandler.ComparableRow>()
          {
              protected ResultHandler.ComparableRow computeNext()
              {
                  ResultStore.RowReader rowReader = new ResultStore.RowReader();
                  tailer.readDocument(rowReader);
                  if (rowReader.isFinished)
                      return endOfData();
                  return new StoredComparableRow(rowReader.rows, defs);
              }
          };
  
          return new StoredResultSet(defs,
                                     hasMoreResultSets,
                                     reader.wasFailed,
                                     new RuntimeException(reader.failureMessage),
                                     () -> rowIterator);
      }
  
      public static ResultHandler.ComparableResultSet failed(String failureMessage)
      {
          return new FailedComparableResultSet(new RuntimeException(failureMessage));
      }
  
      public Iterator<ResultHandler.ComparableRow> iterator()
      {
          return rowIteratorSupplier.get();
      }
  
      public ResultHandler.ComparableColumnDefinitions getColumnDefinitions()
      {
          return defs;
      }
  
      public boolean wasFailed()
      {
          return wasFailed;
      }
  
      public Throwable getFailureException()
      {
          return failureException;
      }
  
      static class StoredComparableRow implements ResultHandler.ComparableRow
      {
          private final List<ByteBuffer> row;
          private final ResultHandler.ComparableColumnDefinitions cds;
  
          public StoredComparableRow(List<ByteBuffer> row, ResultHandler.ComparableColumnDefinitions cds)
          {
              this.row = row;
              this.cds = cds;
          }
  
          public ByteBuffer getBytesUnsafe(int i)
          {
              return row.get(i);
          }
  
          public ResultHandler.ComparableColumnDefinitions getColumnDefinitions()
          {
              return cds;
          }
  
          public boolean equals(Object other)
          {
              if (!(other instanceof StoredComparableRow))
                  return false;
              return row.equals(((StoredComparableRow)other).row);
          }
  
          public int hashCode()
          {
              return Objects.hash(row, cds);
          }
  
          public String toString()
          {
              return row.stream().map(ByteBufferUtil::bytesToHex).collect(Collectors.joining(","));
          }
      }
  
      static class StoredComparableColumnDefinitions implements ResultHandler.ComparableColumnDefinitions
      {
          private final List<ResultHandler.ComparableDefinition> defs;
          private final boolean wasFailed;
          private final Throwable failureException;
  
          public StoredComparableColumnDefinitions(List<Pair<String, String>> cds, boolean wasFailed, Throwable failureException)
          {
              defs = cds != null ? cds.stream().map(StoredComparableDefinition::new).collect(Collectors.toList()) : Collections.emptyList();
              this.wasFailed = wasFailed;
              this.failureException = failureException;
          }
          public List<ResultHandler.ComparableDefinition> asList()
          {
              return wasFailed() ? Collections.emptyList() : defs;
          }
  
          public boolean wasFailed()
          {
              return wasFailed;
          }
  
          public Throwable getFailureException()
          {
              return failureException;
          }
  
          public int size()
          {
              return asList().size();
          }
  
          public Iterator<ResultHandler.ComparableDefinition> iterator()
          {
              return defs.iterator();
          }
  
          public boolean equals(Object other)
          {
              if (!(other instanceof StoredComparableColumnDefinitions))
                  return false;
              return defs.equals(((StoredComparableColumnDefinitions)other).defs);
          }
  
          public int hashCode()
          {
              return Objects.hash(defs, wasFailed, failureException);
          }
  
          public String toString()
          {
              return defs.toString();
          }
      }
  
      private static class StoredComparableDefinition implements ResultHandler.ComparableDefinition
      {
          private final Pair<String, String> p;
  
          public StoredComparableDefinition(Pair<String, String> p)
          {
              this.p = p;
          }
          public String getType()
          {
              return p.right;
          }
  
          public String getName()
          {
              return p.left;
          }
  
          public boolean equals(Object other)
          {
              if (!(other instanceof StoredComparableDefinition))
                  return false;
              return p.equals(((StoredComparableDefinition)other).p);
          }
  
          public int hashCode()
          {
              return Objects.hash(p);
          }
  
          public String toString()
          {
              return getName() + ':' + getType();
          }
      }
  
      private static class FailedComparableResultSet implements ResultHandler.ComparableResultSet
      {
          private final Throwable exception;
  
          public FailedComparableResultSet(Throwable exception)
          {
              this.exception = exception;
          }
          public ResultHandler.ComparableColumnDefinitions getColumnDefinitions()
          {
              return new ResultHandler.ComparableColumnDefinitions()
              {
                  public List<ResultHandler.ComparableDefinition> asList()
                  {
                      return Collections.emptyList();
                  }
  
                  public boolean wasFailed()
                  {
                      return true;
                  }
  
                  public Throwable getFailureException()
                  {
                      return exception;
                  }
  
                  public int size()
                  {
                      return 0;
                  }
  
                  public Iterator<ResultHandler.ComparableDefinition> iterator()
                  {
                      return asList().iterator();
                  }
              };
          }
  
          public boolean wasFailed()
          {
              return true;
          }
  
          public Throwable getFailureException()
          {
              return new RuntimeException();
          }
  
          public Iterator<ResultHandler.ComparableRow> iterator()
          {
              return Collections.emptyListIterator();
          }
      }
  }
  