com.google.appengine.api.search.checkers.IndexChecker Maven / Gradle / Ivy

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/*
 * Copyright 2021 Google LLC
 *
 * 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
 *
 *     https://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 com.google.appengine.api.search.checkers;

import com.google.common.base.Preconditions;
import com.google.common.base.Strings;

/**
 * Checks values of {@link com.google.appengine.api.search.Index Indexes}.
 *
 */
public class IndexChecker {

  /**
   * Checks whether an index name is valid. It must be a ASCII visible
   * printable string of length between 1 and {@literal
   * #MAXIMUM_INDEX_NAME_LENGTH}, not start with '!', and not be of
   * the format __.*__, which are reserved sequences for internal
   * index names.
   *
   * @param indexName the index name to check
   * @return the checked index name
   * @throws IllegalArgumentException if the index name is not valid.
   */
  public static String checkName(String indexName) {
    // TODO: add regex constraint
    Preconditions.checkArgument(!Strings.isNullOrEmpty(indexName), "Index name null or empty");
    Preconditions.checkArgument(
        indexName.length() <= SearchApiLimits.MAXIMUM_INDEX_NAME_LENGTH,
        "Index name longer than %s characters: %s",
        SearchApiLimits.MAXIMUM_INDEX_NAME_LENGTH,
        indexName);
    Preconditions.checkArgument(isAsciiVisiblePrintable(indexName),
        "Index name must be ASCII visible printable: %s", indexName);
    Preconditions.checkArgument(!isReserved(indexName),
        "Index name must not start with !: %s", indexName);
    return indexName;
  }

  /**
   * @return true if all characters are visible ascii printable: that is,
   * between 33 ('!') and 126 ('~'), inclusive
   */
  static boolean isAsciiVisiblePrintable(String str) {
    for (int i = 0; i < str.length(); ++i) {
      if (str.charAt(i) < 33 || str.charAt(i) > 126) {
        return false;
      }
    }
    return true;
  }

  /**
   * @return true if str represents a reserved index name
   */
  static boolean isReserved(String str) {
    return str.startsWith("!")
      || (str.length() > 3 && str.startsWith("__") && str.endsWith("__"));
  }
}