content: /*
   * Copyright (c) 2017, 2022, Oracle and/or its affiliates.
   *
   * This program is free software; you can redistribute it and/or modify it under
   * the terms of the GNU General Public License, version 2.0, as published by the
   * Free Software Foundation.
   *
   * This program is also distributed with certain software (including but not
   * limited to OpenSSL) that is licensed under separate terms, as designated in a
   * particular file or component or in included license documentation. The
   * authors of MySQL hereby grant you an additional permission to link the
   * program and your derivative works with the separately licensed software that
   * they have included with MySQL.
   *
   * Without limiting anything contained in the foregoing, this file, which is
   * part of MySQL Connector/J, is also subject to the Universal FOSS Exception,
   * version 1.0, a copy of which can be found at
   * http://oss.oracle.com/licenses/universal-foss-exception.
   *
   * This program 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 General Public License, version 2.0,
   * for more details.
   *
   * You should have received a copy of the GNU General Public License along with
   * this program; if not, write to the Free Software Foundation, Inc.,
   * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
   */
  
  package com.mysql.cj;
  
  import java.util.TimerTask;
  
  import com.mysql.cj.Query.CancelStatus;
  import com.mysql.cj.conf.HostInfo;
  import com.mysql.cj.conf.PropertyKey;
  import com.mysql.cj.exceptions.OperationCancelledException;
  import com.mysql.cj.protocol.a.NativeMessageBuilder;
  
  //TODO should not be protocol-specific
  
  /**
   * Thread used to implement query timeouts...Eventually we could be more
   * efficient and have one thread with timers, but this is a straightforward
   * and simple way to implement a feature that isn't used all that often.
   */
  public class CancelQueryTaskImpl extends TimerTask implements CancelQueryTask {
  
      Query queryToCancel;
      Throwable caughtWhileCancelling = null;
      boolean queryTimeoutKillsConnection = false;
  
      public CancelQueryTaskImpl(Query cancellee) {
          this.queryToCancel = cancellee;
          NativeSession session = (NativeSession) cancellee.getSession();
          this.queryTimeoutKillsConnection = session.getPropertySet().getBooleanProperty(PropertyKey.queryTimeoutKillsConnection).getValue();
      }
  
      @Override
      public boolean cancel() {
          boolean res = super.cancel();
          this.queryToCancel = null;
          return res;
      }
  
      @Override
      public void run() {
  
          Thread cancelThread = new Thread() {
  
              @Override
              public void run() {
                  Query localQueryToCancel = CancelQueryTaskImpl.this.queryToCancel;
                  if (localQueryToCancel == null) {
                      return;
                  }
                  NativeSession session = (NativeSession) localQueryToCancel.getSession();
                  if (session == null) {
                      return;
                  }
  
                  try {
                      if (CancelQueryTaskImpl.this.queryTimeoutKillsConnection) {
                          localQueryToCancel.setCancelStatus(CancelStatus.CANCELED_BY_TIMEOUT);
                          session.invokeCleanupListeners(new OperationCancelledException(Messages.getString("Statement.ConnectionKilledDueToTimeout")));
                      } else {
                          synchronized (localQueryToCancel.getCancelTimeoutMutex()) {
                              long origConnId = session.getThreadId();
                              HostInfo hostInfo = session.getHostInfo();
                              String database = hostInfo.getDatabase();
                              String user = hostInfo.getUser();
                              String password = hostInfo.getPassword();
  
                              NativeSession newSession = null;
                              try {
                                  newSession = new NativeSession(hostInfo, session.getPropertySet());
                                  newSession.connect(hostInfo, user, password, database, 30000, new TransactionEventHandler() {
                                      @Override
                                      public void transactionCompleted() {
                                      }
  
                                      public void transactionBegun() {
                                      }
                                  });
                                  newSession.getProtocol().sendCommand(new NativeMessageBuilder(newSession.getServerSession().supportsQueryAttributes())
                                          .buildComQuery(newSession.getSharedSendPacket(), "KILL QUERY " + origConnId), false, 0);
                              } finally {
                                  try {
                                      newSession.forceClose();
                                  } catch (Throwable t) {
                                      // no-op.
                                  }
                              }
                              localQueryToCancel.setCancelStatus(CancelStatus.CANCELED_BY_TIMEOUT);
                          }
                      }
                      // } catch (NullPointerException npe) {
                      // Case when connection closed while starting to cancel.
                      // We can't easily synchronize this, because then one thread can't cancel() a running query.
                      // Ignore, we shouldn't re-throw this, because the connection's already closed, so the statement has been timed out.
                  } catch (Throwable t) {
                      CancelQueryTaskImpl.this.caughtWhileCancelling = t;
                  } finally {
                      setQueryToCancel(null);
                  }
              }
          };
  
          cancelThread.start();
      }
  
      public Throwable getCaughtWhileCancelling() {
          return this.caughtWhileCancelling;
      }
  
      public void setCaughtWhileCancelling(Throwable caughtWhileCancelling) {
          this.caughtWhileCancelling = caughtWhileCancelling;
      }
  
      public Query getQueryToCancel() {
          return this.queryToCancel;
      }
  
      public void setQueryToCancel(Query queryToCancel) {
          this.queryToCancel = queryToCancel;
      }
  }
  