package davmail.exchange;
   
   import davmail.Settings;
   import org.apache.log4j.Logger;
   
   import javax.mail.MessagingException;
   import java.io.IOException;
   import java.io.OutputStream;
   import java.net.SocketException;
  
  /**
   * Message load thread.
   * Used to avoid timeouts over POP and IMAP
   */
  public class MessageLoadThread extends Thread {
      private static final Logger LOGGER = Logger.getLogger(MessageLoadThread.class);
  
      protected volatile boolean isComplete = false;
      protected ExchangeSession.Message message;
      protected IOException ioException;
      protected MessagingException messagingException;
  
      protected MessageLoadThread(String threadName, ExchangeSession.Message message) {
          super(threadName + "-LoadMessage");
          setDaemon(true);
          this.message = message;
      }
  
      public void run() {
          try {
              message.loadMimeMessage();
          } catch (IOException e) {
              ioException = e;
          } catch (MessagingException e) {
              messagingException = e;
          } finally {
              isComplete = true;
          }
      }
  
      /**
       * Load mime message in a separate thread if over 1MB.
       * Send a space character every ten seconds to avoid client timeouts
       *
       * @param message      message
       * @param outputStream output stream
       * @throws IOException        on error
       * @throws MessagingException on error
       */
      public static void loadMimeMessage(ExchangeSession.Message message, OutputStream outputStream) throws IOException, MessagingException {
          if (message.size < 1024 * 1024) {
              message.loadMimeMessage();
          } else {
              LOGGER.debug("Load large message " + (message.size / 1024) + "KB uid " + message.getUid() + " imapUid " + message.getImapUid() + " in a separate thread");
              MessageLoadThread messageLoadThread = new MessageLoadThread(currentThread().getName(), message);
              messageLoadThread.start();
              while (!messageLoadThread.isComplete) {
                  try {
                      messageLoadThread.join(10000);
                  } catch (InterruptedException e) {
                      LOGGER.warn("Thread interrupted", e);
                      Thread.currentThread().interrupt();
                  }
                  if (!messageLoadThread.isComplete) {
                      LOGGER.debug("Still loading uid " + message.getUid() + " imapUid " + message.getImapUid());
                      if (Settings.getBooleanProperty("davmail.enableKeepAlive", false)) {
                          try {
                              outputStream.write(' ');
                              outputStream.flush();
                          } catch (SocketException e) {
                              // client closed connection, stop thread
                              messageLoadThread.interrupt();
                              try {
                                  messageLoadThread.join(1000);
                              } catch (InterruptedException ie) {
                                  Thread.currentThread().interrupt();
                              }
                              message.dropMimeMessage();
                              throw e;
                          }
                      }
                  }
              }
              if (messageLoadThread.ioException != null) {
                  throw messageLoadThread.ioException;
              }
              if (messageLoadThread.messagingException != null) {
                  throw messageLoadThread.messagingException;
              }
          }
      }
  }