src/main/java/org/apache/accumulo/access/AccessExpressionImpl.java

/*
 * 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
 *
 *   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 org.apache.accumulo.access;

import static java.nio.charset.StandardCharsets.UTF_8;

import java.util.HashSet;
import java.util.function.Predicate;

final class AccessExpressionImpl implements AccessExpression {

  public static final AccessExpression EMPTY = new AccessExpressionImpl("", false);

  private final String expression;

  AccessExpressionImpl(String expression, boolean normalize) {
    if (normalize) {
      // validate and normalize expression
      this.expression = normalize(expression);
    } else {
      validate(expression);
      this.expression = expression;
    }
  }

  AccessExpressionImpl(byte[] expression, boolean normalize) {
    if (normalize) {
      // validate and normalize expression
      this.expression = normalize(expression);
    } else {
      validate(expression);
      this.expression = new String(expression, UTF_8);
    }
  }

  @Override
  public String getExpression() {
    return expression;
  }

  @Override
  public String toString() {
    return expression;
  }

  @Override
  public boolean equals(Object o) {
    if (o instanceof AccessExpressionImpl) {
      return ((AccessExpressionImpl) o).expression.equals(expression);
    }

    return false;
  }

  @Override
  public int hashCode() {
    return expression.hashCode();
  }

  @Override
  public Authorizations getAuthorizations() {
    return AccessExpressionImpl.getAuthorizations(expression);
  }

  static Authorizations getAuthorizations(byte[] expression) {
    HashSet<String> auths = new HashSet<>();
    Tokenizer tokenizer = new Tokenizer(expression);
    Predicate<Tokenizer.AuthorizationToken> atp = authToken -> {
      auths.add(new String(authToken.data, authToken.start, authToken.len, UTF_8));
      return true;
    };
    ParserEvaluator.parseAccessExpression(tokenizer, atp, atp);
    return Authorizations.of(auths);
  }

  static Authorizations getAuthorizations(String expression) {
    return getAuthorizations(expression.getBytes(UTF_8));
  }

  static String quote(String term) {
    return new String(quote(term.getBytes(UTF_8)), UTF_8);
  }

  /**
   * Properly quotes terms in an AccessExpression. If no quoting is needed, then nothing is done.
   *
   * @param term term to quote, encoded as UTF-8 bytes
   * @return quoted term (unquoted if unnecessary), encoded as UTF-8 bytes
   * @see #quote(String)
   */
  static byte[] quote(byte[] term) {
    boolean needsQuote = false;

    for (byte b : term) {
      if (!Tokenizer.isValidAuthChar(b)) {
        needsQuote = true;
        break;
      }
    }

    if (!needsQuote) {
      return term;
    }

    return AccessEvaluatorImpl.escape(term, true);
  }

  static void validate(byte[] expression) throws IllegalAccessExpressionException {
    Tokenizer tokenizer = new Tokenizer(expression);
    Predicate<Tokenizer.AuthorizationToken> atp = authToken -> true;
    ParserEvaluator.parseAccessExpression(tokenizer, atp, atp);
  }

  static void validate(String expression) throws IllegalAccessExpressionException {
    validate(expression.getBytes(UTF_8));
  }

  static String normalize(String expression) throws IllegalAccessExpressionException {
    Tokenizer tokenizer = new Tokenizer(expression.getBytes(UTF_8));
    return Normalizer.normalize(tokenizer);
  }

  static String normalize(byte[] expression) throws IllegalAccessExpressionException {
    Tokenizer tokenizer = new Tokenizer(expression);
    return Normalizer.normalize(tokenizer);
  }

}