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.calcite.adapter.enumerable;
  
  import org.apache.calcite.adapter.java.JavaTypeFactory;
  import org.apache.calcite.linq4j.tree.BlockBuilder;
  import org.apache.calcite.linq4j.tree.Expression;
  import org.apache.calcite.linq4j.tree.Expressions;
  import org.apache.calcite.linq4j.tree.ParameterExpression;
  import org.apache.calcite.linq4j.tree.Types;
  import org.apache.calcite.plan.RelOptCluster;
  import org.apache.calcite.plan.RelOptTable;
  import org.apache.calcite.plan.RelTraitSet;
  import org.apache.calcite.prepare.Prepare;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.core.TableModify;
  import org.apache.calcite.rex.RexNode;
  import org.apache.calcite.schema.ModifiableTable;
  import org.apache.calcite.util.BuiltInMethod;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.lang.reflect.Method;
  import java.lang.reflect.Modifier;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  
  import static com.google.common.base.Preconditions.checkArgument;
  
  import static java.util.Objects.requireNonNull;
  
  /** Implementation of {@link org.apache.calcite.rel.core.TableModify} in
   * {@link org.apache.calcite.adapter.enumerable.EnumerableConvention enumerable calling convention}. */
  public class EnumerableTableModify extends TableModify
      implements EnumerableRel {
    public EnumerableTableModify(RelOptCluster cluster, RelTraitSet traits,
        RelOptTable table, Prepare.CatalogReader catalogReader, RelNode child,
        Operation operation, @Nullable List<String> updateColumnList,
        @Nullable List<RexNode> sourceExpressionList, boolean flattened) {
      super(cluster, traits, table, catalogReader, child, operation,
          updateColumnList, sourceExpressionList, flattened);
      assert child.getConvention() instanceof EnumerableConvention;
      assert getConvention() instanceof EnumerableConvention;
      final ModifiableTable modifiableTable =
          table.unwrap(ModifiableTable.class);
      if (modifiableTable == null) {
        throw new AssertionError(); // TODO: user error in validator
      }
    }
  
    @Override public RelNode copy(RelTraitSet traitSet, List<RelNode> inputs) {
      return new EnumerableTableModify(
          getCluster(),
          traitSet,
          getTable(),
          getCatalogReader(),
          sole(inputs),
          getOperation(),
          getUpdateColumnList(),
          getSourceExpressionList(),
          isFlattened());
    }
  
    @Override public Result implement(EnumerableRelImplementor implementor, Prefer pref) {
      final BlockBuilder builder = new BlockBuilder();
      final Result result =
          implementor.visitChild(this, 0, (EnumerableRel) getInput(), pref);
      Expression childExp =
          builder.append(
              "child", result.block);
      final ParameterExpression collectionParameter =
          Expressions.parameter(Collection.class,
              builder.newName("collection"));
      final Expression expression = table.getExpression(ModifiableTable.class);
      requireNonNull(expression, "expression"); // TODO: user error in validator
      checkArgument(
          ModifiableTable.class.isAssignableFrom(
              Types.toClass(expression.getType())),
          "not assignable from type %s", expression.getType());
      builder.add(
          Expressions.declare(
              Modifier.FINAL,
              collectionParameter,
              Expressions.call(
                  expression,
                  BuiltInMethod.MODIFIABLE_TABLE_GET_MODIFIABLE_COLLECTION
                      .method)));
      final Expression countParameter =
          builder.append(
              "count",
              Expressions.call(collectionParameter, "size"),
              false);
      Expression convertedChildExp;
      if (!getInput().getRowType().equals(getRowType())) {
        final JavaTypeFactory typeFactory =
            (JavaTypeFactory) getCluster().getTypeFactory();
        final JavaRowFormat format = EnumerableTableScan.deduceFormat(table);
        PhysType physType =
            PhysTypeImpl.of(typeFactory, table.getRowType(), format);
        List<Expression> expressionList = new ArrayList<>();
        final PhysType childPhysType = result.physType;
        final ParameterExpression o_ =
            Expressions.parameter(childPhysType.getJavaRowType(), "o");
        final int fieldCount =
            childPhysType.getRowType().getFieldCount();
        for (int i = 0; i < fieldCount; i++) {
          expressionList.add(
              childPhysType.fieldReference(o_, i, physType.getJavaFieldType(i)));
        }
        convertedChildExp =
            builder.append(
                "convertedChild",
                Expressions.call(
                    childExp,
                    BuiltInMethod.SELECT.method,
                    Expressions.lambda(
                        physType.record(expressionList), o_)));
      } else {
        convertedChildExp = childExp;
      }
      final Method method;
      switch (getOperation()) {
      case INSERT:
        method = BuiltInMethod.INTO.method;
        break;
      case DELETE:
        method = BuiltInMethod.REMOVE_ALL.method;
        break;
      default:
        throw new AssertionError(getOperation());
      }
      builder.add(
          Expressions.statement(
              Expressions.call(
                  convertedChildExp, method, collectionParameter)));
      final Expression updatedCountParameter =
          builder.append(
              "updatedCount",
              Expressions.call(collectionParameter, "size"),
              false);
      builder.add(
          Expressions.return_(
              null,
              Expressions.call(
                  BuiltInMethod.SINGLETON_ENUMERABLE.method,
                  Expressions.convert_(
                      Expressions.condition(
                          Expressions.greaterThanOrEqual(
                              updatedCountParameter, countParameter),
                          Expressions.subtract(
                              updatedCountParameter, countParameter),
                          Expressions.subtract(
                              countParameter, updatedCountParameter)),
                      long.class))));
      final PhysType physType =
          PhysTypeImpl.of(
              implementor.getTypeFactory(),
              getRowType(),
              pref == Prefer.ARRAY
                  ? JavaRowFormat.ARRAY : JavaRowFormat.SCALAR);
      return implementor.result(physType, builder.toBlock());
    }
  
  }
  