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.cql3.terms;
  
  import java.nio.ByteBuffer;
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Objects;
  import java.util.Set;
  import java.util.stream.Collectors;
  
  import org.apache.cassandra.cql3.AssignmentTestable;
  import org.apache.cassandra.cql3.ColumnIdentifier;
  import org.apache.cassandra.cql3.ColumnSpecification;
  import org.apache.cassandra.cql3.Operation;
  import org.apache.cassandra.cql3.QueryOptions;
  import org.apache.cassandra.cql3.UpdateParameters;
  import org.apache.cassandra.cql3.VariableSpecifications;
  import org.apache.cassandra.db.DecoratedKey;
  import org.apache.cassandra.db.guardrails.Guardrails;
  import org.apache.cassandra.db.marshal.AbstractType;
  import org.apache.cassandra.db.marshal.MapType;
  import org.apache.cassandra.db.marshal.MultiElementType;
  import org.apache.cassandra.db.rows.Cell;
  import org.apache.cassandra.db.rows.CellPath;
  import org.apache.cassandra.exceptions.InvalidRequestException;
  import org.apache.cassandra.schema.ColumnMetadata;
  import org.apache.cassandra.utils.ByteBufferUtil;
  import org.apache.cassandra.utils.Pair;
  
  import static org.apache.cassandra.cql3.terms.Constants.UNSET_VALUE;
  
  /**
   * Static helper methods and classes for maps.
   */
  public final class Maps
  {
      private Maps() {}
  
      public static ColumnSpecification keySpecOf(ColumnSpecification column)
      {
          return new ColumnSpecification(column.ksName, column.cfName, new ColumnIdentifier("key(" + column.name + ')', true), keysType(column.type));
      }
  
      public static ColumnSpecification valueSpecOf(ColumnSpecification column)
      {
          return new ColumnSpecification(column.ksName, column.cfName, new ColumnIdentifier("value(" + column.name + ')', true), valuesType(column.type));
      }
  
      private static AbstractType<?> keysType(AbstractType<?> type)
      {
          return ((MapType<?, ?>) type.unwrap()).getKeysType();
      }
  
      private static AbstractType<?> valuesType(AbstractType<?> type)
      {
          return ((MapType<?, ?>) type.unwrap()).getValuesType();
      }
  
      /**
       * Tests that the map with the specified entries can be assigned to the specified column.
       *
       * @param receiver the receiving column
       * @param entries the map entries
       */
      public static <T extends AssignmentTestable> AssignmentTestable.TestResult testMapAssignment(ColumnSpecification receiver,
                                                                                                   List<Pair<T, T>> entries)
      {
          ColumnSpecification keySpec = keySpecOf(receiver);
          ColumnSpecification valueSpec = valueSpecOf(receiver);
  
          // It's an exact match if all are exact match, but is not assignable as soon as any is non assignable.
          AssignmentTestable.TestResult res = AssignmentTestable.TestResult.EXACT_MATCH;
          for (Pair<T, T> entry : entries)
          {
              AssignmentTestable.TestResult t1 = entry.left.testAssignment(receiver.ksName, keySpec);
              AssignmentTestable.TestResult t2 = entry.right.testAssignment(receiver.ksName, valueSpec);
              if (t1 == AssignmentTestable.TestResult.NOT_ASSIGNABLE || t2 == AssignmentTestable.TestResult.NOT_ASSIGNABLE)
                  return AssignmentTestable.TestResult.NOT_ASSIGNABLE;
              if (t1 != AssignmentTestable.TestResult.EXACT_MATCH || t2 != AssignmentTestable.TestResult.EXACT_MATCH)
                  res = AssignmentTestable.TestResult.WEAKLY_ASSIGNABLE;
          }
          return res;
      }
  
      /**
       * Create a <code>String</code> representation of the list containing the specified elements.
       *
       * @param entries the list elements
       * @return a <code>String</code> representation of the list
       */
      public static <T> String mapToString(List<Pair<T, T>> entries)
      {
          return mapToString(entries, Object::toString);
      }
  
      /**
       * Create a <code>String</code> representation of the map from the specified items associated to
       * the map entries.
       *
       * @param items items associated to the map entries
       * @param mapper the mapper used to map the items to the <code>String</code> representation of the map entries
       * @return a <code>String</code> representation of the map
       */
      public static <T> String mapToString(List<Pair<T, T>> items,
                                           java.util.function.Function<T, String> mapper)
      {
          return items.stream()
                  .map(p -> String.format("%s: %s", mapper.apply(p.left), mapper.apply(p.right)))
                  .collect(Collectors.joining(", ", "{", "}"));
      }
  
      /**
       * Returns the exact MapType from the entries if it can be known.
       *
       * @param entries the entries
       * @param mapper the mapper used to retrieve the key and value types from the entries
       * @return the exact MapType from the entries if it can be known or <code>null</code>
       */
      public static <T> MapType<?, ?> getExactMapTypeIfKnown(List<Pair<T, T>> entries,
                                                             java.util.function.Function<T, AbstractType<?>> mapper)
      {
          AbstractType<?> keyType = null;
          AbstractType<?> valueType = null;
          for (Pair<T, T> entry : entries)
          {
              if (keyType == null)
                  keyType = mapper.apply(entry.left);
              if (valueType == null)
                  valueType = mapper.apply(entry.right);
              if (keyType != null && valueType != null)
                  return MapType.getInstance(keyType, valueType, false);
          }
          return null;
      }
  
      public static <T> MapType<?, ?> getPreferredCompatibleType(List<Pair<T, T>> entries,
                                                                 java.util.function.Function<T, AbstractType<?>> mapper)
      {
          Set<AbstractType<?>> keyTypes = entries.stream().map(Pair::left).map(mapper).filter(Objects::nonNull).collect(Collectors.toSet());
          AbstractType<?> keyType = AssignmentTestable.getCompatibleTypeIfKnown(keyTypes);
          if (keyType == null)
              return null;
  
          Set<AbstractType<?>> valueTypes = entries.stream().map(Pair::right).map(mapper).filter(Objects::nonNull).collect(Collectors.toSet());
          AbstractType<?> valueType = AssignmentTestable.getCompatibleTypeIfKnown(valueTypes);
          if (valueType == null)
              return null;
  
          return  MapType.getInstance(keyType, valueType, false);
      }
  
      public static class Literal extends Term.Raw
      {
          public final List<Pair<Term.Raw, Term.Raw>> entries;
  
          public Literal(List<Pair<Term.Raw, Term.Raw>> entries)
          {
              this.entries = entries;
          }
  
          public Term prepare(String keyspace, ColumnSpecification receiver) throws InvalidRequestException
          {
              validateAssignableTo(keyspace, receiver);
  
              ColumnSpecification keySpec = Maps.keySpecOf(receiver);
              ColumnSpecification valueSpec = Maps.valueSpecOf(receiver);
              // In CQL maps are represented as a list of key value pairs (e.g. {k1 : v1, k2 : v2, ...}).
              // Whereas, internally maps are serialized as a lists where each key is followed by its value (e.g. [k1, v1, k2, v2, ...])
              // Therefore, we must go from one format to another.
              List<Term> values = new ArrayList<>(entries.size() << 1);
              boolean allTerminal = true;
              for (Pair<Term.Raw, Term.Raw> entry : entries)
              {
                  Term k = entry.left.prepare(keyspace, keySpec);
                  Term v = entry.right.prepare(keyspace, valueSpec);
  
                  if (k.containsBindMarker() || v.containsBindMarker())
                      throw new InvalidRequestException(String.format("Invalid map literal for %s: bind variables are not supported inside collection literals", receiver.name));
  
                  if (k instanceof Term.NonTerminal || v instanceof Term.NonTerminal)
                      allTerminal = false;
  
                  values.add(k);
                  values.add(v);
              }
              MultiElements.DelayedValue value = new MultiElements.DelayedValue((MultiElementType<?>) receiver.type.unwrap(), values);
              return allTerminal ? value.bind(QueryOptions.DEFAULT) : value;
          }
  
          private void validateAssignableTo(String keyspace, ColumnSpecification receiver) throws InvalidRequestException
          {
              AbstractType<?> type = receiver.type.unwrap();
  
              if (!(type instanceof MapType))
                  throw new InvalidRequestException(String.format("Invalid map literal for %s of type %s", receiver.name, receiver.type.asCQL3Type()));
  
              ColumnSpecification keySpec = Maps.keySpecOf(receiver);
              ColumnSpecification valueSpec = Maps.valueSpecOf(receiver);
              for (Pair<Term.Raw, Term.Raw> entry : entries)
              {
                  if (!entry.left.testAssignment(keyspace, keySpec).isAssignable())
                      throw new InvalidRequestException(String.format("Invalid map literal for %s: key %s is not of type %s", receiver.name, entry.left, keySpec.type.asCQL3Type()));
                  if (!entry.right.testAssignment(keyspace, valueSpec).isAssignable())
                      throw new InvalidRequestException(String.format("Invalid map literal for %s: value %s is not of type %s", receiver.name, entry.right, valueSpec.type.asCQL3Type()));
              }
          }
  
          public AssignmentTestable.TestResult testAssignment(String keyspace, ColumnSpecification receiver)
          {
              return testMapAssignment(receiver, entries);
          }
  
          @Override
          public AbstractType<?> getExactTypeIfKnown(String keyspace)
          {
              return getExactMapTypeIfKnown(entries, p -> p.getExactTypeIfKnown(keyspace));
          }
  
          @Override
          public AbstractType<?> getCompatibleTypeIfKnown(String keyspace)
          {
              return Maps.getPreferredCompatibleType(entries, p -> p.getCompatibleTypeIfKnown(keyspace));
          }
  
          public String getText()
          {
              return mapToString(entries, Term.Raw::getText);
          }
      }
  
      public static class Setter extends Operation
      {
          public Setter(ColumnMetadata column, Term t)
          {
              super(column, t);
          }
  
          public void execute(DecoratedKey partitionKey, UpdateParameters params) throws InvalidRequestException
          {
              Term.Terminal value = t.bind(params.options);
              if (value == UNSET_VALUE)
                  return;
  
              // delete + put
              if (column.type.isMultiCell())
                  params.setComplexDeletionTimeForOverwrite(column);
              Putter.doPut(value, column, params);
          }
      }
  
      public static class SetterByKey extends Operation
      {
          public final Term k;
  
          public SetterByKey(ColumnMetadata column, Term k, Term t)
          {
              super(column, t);
              this.k = k;
          }
  
          @Override
          public void collectMarkerSpecification(VariableSpecifications boundNames)
          {
              super.collectMarkerSpecification(boundNames);
              k.collectMarkerSpecification(boundNames);
          }
  
          public void execute(DecoratedKey partitionKey, UpdateParameters params) throws InvalidRequestException
          {
              assert column.type.isMultiCell() : "Attempted to set a value for a single key on a frozen map";
              ByteBuffer key = k.bindAndGet(params.options);
              ByteBuffer value = t.bindAndGet(params.options);
              if (key == null)
                  throw new InvalidRequestException("Invalid null map key");
              if (key == ByteBufferUtil.UNSET_BYTE_BUFFER)
                  throw new InvalidRequestException("Invalid unset map key");
  
              CellPath path = CellPath.create(key);
  
              if (value == null)
              {
                  params.addTombstone(column, path);
              }
              else if (value != ByteBufferUtil.UNSET_BYTE_BUFFER)
              {
                  params.addCell(column, path, value);
              }
          }
      }
  
      public static class Putter extends Operation
      {
          public Putter(ColumnMetadata column, Term t)
          {
              super(column, t);
          }
  
          public void execute(DecoratedKey partitionKey, UpdateParameters params) throws InvalidRequestException
          {
              assert column.type.isMultiCell() : "Attempted to add items to a frozen map";
              Term.Terminal value = t.bind(params.options);
              if (value != UNSET_VALUE)
                  doPut(value, column, params);
          }
  
          static void doPut(Term.Terminal value, ColumnMetadata column, UpdateParameters params) throws InvalidRequestException
          {
              MapType<?, ?> type = (MapType<?, ?>) column.type;
  
              if (value == null)
              {
                  // for frozen maps, we're overwriting the whole cell
                  if (!type.isMultiCell())
                      params.addTombstone(column);
  
                  return;
              }
  
              List<ByteBuffer> elements = value.getElements();
  
              if (type.isMultiCell())
              {
                  if (elements.isEmpty())
                      return;
  
                  // Guardrails about collection size are only checked for the added elements without considering
                  // already existent elements. This is done so to avoid read-before-write, having additional checks
                  // during SSTable write.
                  Guardrails.itemsPerCollection.guard(type.collectionSize(elements), column.name.toString(), false, params.clientState);
  
                  int dataSize = 0;
                  Iterator<ByteBuffer> iter = elements.iterator();
                  while(iter.hasNext())
                  {
                      Cell<?> cell = params.addCell(column, CellPath.create(iter.next()), iter.next());
                      dataSize += cell.dataSize();
                  }
                  Guardrails.collectionMapSize.guard(dataSize, column.name.toString(), false, params.clientState);
              }
              else
              {
                  Guardrails.itemsPerCollection.guard(type.collectionSize(elements), column.name.toString(), false, params.clientState);
                  Cell<?> cell = params.addCell(column, value.get());
                  Guardrails.collectionMapSize.guard(cell.dataSize(), column.name.toString(), false, params.clientState);
              }
          }
      }
  
      public static class DiscarderByKey extends Operation
      {
          public DiscarderByKey(ColumnMetadata column, Term k)
          {
              super(column, k);
          }
  
          public void execute(DecoratedKey partitionKey, UpdateParameters params) throws InvalidRequestException
          {
              assert column.type.isMultiCell() : "Attempted to delete a single key in a frozen map";
              Term.Terminal key = t.bind(params.options);
              if (key == null)
                  throw new InvalidRequestException("Invalid null map key");
              if (key == Constants.UNSET_VALUE)
                  throw new InvalidRequestException("Invalid unset map key");
  
              params.addTombstone(column, CellPath.create(key.get()));
          }
      }
  }
  