com.pingcap.tikv.expression.visitor.MetaResolver Maven / Gradle / Ivy

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/*
 * Copyright 2017 PingCAP, Inc.
 *
 * Licensed 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,
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.pingcap.tikv.expression.visitor;

import com.pingcap.tikv.expression.ColumnRef;
import com.pingcap.tikv.expression.ComparisonBinaryExpression;
import com.pingcap.tikv.expression.ComparisonBinaryExpression.NormalizedPredicate;
import com.pingcap.tikv.expression.Expression;
import com.pingcap.tikv.meta.TiTableInfo;
import java.util.List;
import java.util.Objects;

public class MetaResolver extends DefaultVisitor {
  private final TiTableInfo table;

  public MetaResolver(TiTableInfo table) {
    this.table = table;
  }

  public static void resolve(Expression expression, TiTableInfo table) {
    MetaResolver resolver = new MetaResolver(table);
    resolver.resolve(expression);
  }

  public static void resolve(List expressions, TiTableInfo table) {
    MetaResolver resolver = new MetaResolver(table);
    resolver.resolve(expressions);
  }

  public void resolve(List expressions) {
    expressions.forEach(expression -> expression.accept(this, null));
  }

  public void resolve(Expression expression) {
    Objects.requireNonNull(expression, "expression is null");
    expression.accept(this, null);
  }

  @Override
  protected Void visit(ComparisonBinaryExpression node, Expression parent) {
    NormalizedPredicate predicate = node.normalize();
    // TODO(Zhexuan Yang): fix this if we have complex ComparisonBinaryExpression
    // We may need add a expressionRewriter to address this.
    if (predicate != null) {
      visit(predicate.getColumnRef(), node);
      // do not set the constant data type to the column ref data type if they are the
      // same catalog because it may narrow the constant type, and cause wrong result.
      // for example when the filter is `bit_col op long_constant`, set long_constant
      // to bit type will truncated the long_constant, and may cause wrong result
      if (predicate.getValue().getDataType() == null
          || !predicate
              .getValue()
              .getDataType()
              .isSameCatalog(predicate.getColumnRef().getDataType()))
        predicate.getValue().setDataType(predicate.getColumnRef().getDataType());
    }
    return null;
  }

  @Override
  protected Void visit(ColumnRef node, Expression parent) {
    node.resolve(table);
    return null;
  }
}