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JDBC driver for MariaDB and MySQL
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/*
 *
 * MariaDB Client for Java
 *
 * Copyright (c) 2012-2014 Monty Program Ab.
 * Copyright (c) 2015-2019 MariaDB Ab.
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along
 * with this library; if not, write to Monty Program Ab [email protected].
 *
 * This particular MariaDB Client for Java file is work
 * derived from a Drizzle-JDBC. Drizzle-JDBC file which is covered by subject to
 * the following copyright and notice provisions:
 *
 * Copyright (c) 2009-2011, Marcus Eriksson
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 * Redistributions of source code must retain the above copyright notice, this list
 * of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice, this
 * list of conditions and the following disclaimer in the documentation and/or
 * other materials provided with the distribution.
 *
 * Neither the name of the driver nor the names of its contributors may not be
 * used to endorse or promote products derived from this software without specific
 * prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS  AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 */

package org.mariadb.jdbc.internal.util.dao;

import org.mariadb.jdbc.internal.*;
import org.mariadb.jdbc.internal.com.read.resultset.*;
import org.mariadb.jdbc.internal.protocol.*;

import java.util.concurrent.atomic.*;

public class ServerPrepareResult implements PrepareResult {

  private final ColumnInformation[] columns;
  private final ColumnInformation[] parameters;
  private final String sql;
  private final AtomicBoolean inCache = new AtomicBoolean();
  private int statementId;
  private ColumnType[] parameterTypeHeader;
  private Protocol unProxiedProtocol;
  // share indicator
  private volatile int shareCounter = 1;
  private volatile boolean isBeingDeallocate;

  /**
   * PrepareStatement Result object.
   *
   * @param sql query
   * @param statementId server statement Id.
   * @param columns columns information
   * @param parameters parameters information
   * @param unProxiedProtocol indicate the protocol on which the prepare has been done
   */
  public ServerPrepareResult(
      String sql,
      int statementId,
      ColumnInformation[] columns,
      ColumnInformation[] parameters,
      Protocol unProxiedProtocol) {
    this.sql = sql;
    this.statementId = statementId;
    this.columns = columns;
    this.parameters = parameters;
    this.unProxiedProtocol = unProxiedProtocol;
    this.parameterTypeHeader = new ColumnType[parameters.length];
  }

  public void resetParameterTypeHeader() {
    this.parameterTypeHeader = new ColumnType[parameters.length];
  }

  /**
   * Update information after a failover.
   *
   * @param statementId new statement Id
   * @param unProxiedProtocol the protocol on which the prepare has been done
   */
  public void failover(int statementId, Protocol unProxiedProtocol) {
    this.statementId = statementId;
    this.unProxiedProtocol = unProxiedProtocol;
    this.parameterTypeHeader = new ColumnType[parameters.length];
    this.shareCounter = 1;
    this.isBeingDeallocate = false;
  }

  public void setAddToCache() {
    inCache.set(true);
  }

  public void setRemoveFromCache() {
    inCache.set(false);
  }

  /**
   * Increment share counter.
   *
   * @return true if can be used (is not been deallocate).
   */
  public synchronized boolean incrementShareCounter() {

    if (isBeingDeallocate) {
      return false;
    }

    shareCounter++;
    return true;
  }

  public synchronized void decrementShareCounter() {
    shareCounter--;
  }

  /**
   * Asked if can be deallocate (is not shared in other statement and not in cache) Set deallocate
   * flag to true if so.
   *
   * @return true if can be deallocate
   */
  public synchronized boolean canBeDeallocate() {
    if (shareCounter > 0 || isBeingDeallocate) {
      return false;
    }
    if (!inCache.get()) {
      isBeingDeallocate = true;
      return true;
    }
    return false;
  }

  public int getParamCount() {
    return parameters.length;
  }

  // for unit test
  public synchronized int getShareCounter() {
    return shareCounter;
  }

  public int getStatementId() {
    return statementId;
  }

  public ColumnInformation[] getColumns() {
    return columns;
  }

  public ColumnInformation[] getParameters() {
    return parameters;
  }

  public Protocol getUnProxiedProtocol() {
    return unProxiedProtocol;
  }

  public String getSql() {
    return sql;
  }

  public ColumnType[] getParameterTypeHeader() {
    return parameterTypeHeader;
  }
}