@Override
 public void loadAttachmentProgress(int progress) {
   try {
     mCallback.loadAttachmentStatus(
         mMessageId, mAttachmentId, EmailServiceStatus.IN_PROGRESS, progress);
   } catch (final RemoteException e) {
     // No danger if the client is no longer around
   }
 }
  @Override
  public void loadAttachment(
      final IEmailServiceCallback cb, final long attachmentId, final boolean background)
      throws RemoteException {
    /// M: We Can't load attachment in low storage state @{
    if (StorageLowState.checkIfStorageLow(mContext)) {
      LogUtils.e(Logging.LOG_TAG, "Can't load attachment due to low storage");
      cb.loadAttachmentStatus(0, attachmentId, EmailServiceStatus.SUCCESS, 0);
      return;
    }
    /// @}
    Folder remoteFolder = null;
    try {
      // 1. Check if the attachment is already here and return early in that case
      Attachment attachment = Attachment.restoreAttachmentWithId(mContext, attachmentId);
      if (attachment == null) {
        cb.loadAttachmentStatus(0, attachmentId, EmailServiceStatus.ATTACHMENT_NOT_FOUND, 0);
        return;
      }
      final long messageId = attachment.mMessageKey;

      final EmailContent.Message message =
          EmailContent.Message.restoreMessageWithId(mContext, attachment.mMessageKey);
      if (message == null) {
        cb.loadAttachmentStatus(messageId, attachmentId, EmailServiceStatus.MESSAGE_NOT_FOUND, 0);
        return;
      }

      // If the message is loaded, just report that we're finished
      if (Utility.attachmentExists(mContext, attachment)
          && attachment.mUiState == UIProvider.AttachmentState.SAVED) {
        cb.loadAttachmentStatus(messageId, attachmentId, EmailServiceStatus.SUCCESS, 0);
        return;
      }

      // Say we're starting...
      cb.loadAttachmentStatus(messageId, attachmentId, EmailServiceStatus.IN_PROGRESS, 0);

      // 2. Open the remote folder.
      final Account account = Account.restoreAccountWithId(mContext, message.mAccountKey);
      Mailbox mailbox = Mailbox.restoreMailboxWithId(mContext, message.mMailboxKey);

      if (mailbox.mType == Mailbox.TYPE_OUTBOX
          /// M: View an attachment which comes from refMessage need sourceKey to identify
          || mailbox.mType == Mailbox.TYPE_DRAFTS) {
        long sourceId =
            Utility.getFirstRowLong(
                mContext,
                Body.CONTENT_URI,
                new String[] {BodyColumns.SOURCE_MESSAGE_KEY},
                BodyColumns.MESSAGE_KEY + "=?",
                new String[] {Long.toString(messageId)},
                null,
                0,
                -1L);
        if (sourceId != -1) {
          EmailContent.Message sourceMsg =
              EmailContent.Message.restoreMessageWithId(mContext, sourceId);
          if (sourceMsg != null) {
            mailbox = Mailbox.restoreMailboxWithId(mContext, sourceMsg.mMailboxKey);
            message.mServerId = sourceMsg.mServerId;
          }
        }
      } else if (mailbox.mType == Mailbox.TYPE_SEARCH && message.mMainMailboxKey != 0) {
        mailbox = Mailbox.restoreMailboxWithId(mContext, message.mMainMailboxKey);
      }

      if (account == null || mailbox == null) {
        // If the account/mailbox are gone, just report success; the UI handles this
        cb.loadAttachmentStatus(messageId, attachmentId, EmailServiceStatus.SUCCESS, 0);
        return;
      }
      TrafficStats.setThreadStatsTag(TrafficFlags.getAttachmentFlags(mContext, account));

      final Store remoteStore = Store.getInstance(account, mContext);
      remoteFolder = remoteStore.getFolder(mailbox.mServerId);
      remoteFolder.open(OpenMode.READ_WRITE);

      // 3. Generate a shell message in which to retrieve the attachment,
      // and a shell BodyPart for the attachment.  Then glue them together.
      final Message storeMessage = remoteFolder.createMessage(message.mServerId);
      final MimeBodyPart storePart = new MimeBodyPart();
      storePart.setSize((int) attachment.mSize);
      storePart.setHeader(MimeHeader.HEADER_ANDROID_ATTACHMENT_STORE_DATA, attachment.mLocation);
      storePart.setHeader(
          MimeHeader.HEADER_CONTENT_TYPE,
          String.format("%s;\n name=\"%s\"", attachment.mMimeType, attachment.mFileName));

      // TODO is this always true for attachments?  I think we dropped the
      // true encoding along the way
      /// M: set encoding type according to data base record.
      String encoding = attachment.mEncoding;
      if (TextUtils.isEmpty(encoding)) {
        encoding = "base64";
      }
      storePart.setHeader(MimeHeader.HEADER_CONTENT_TRANSFER_ENCODING, encoding);

      final MimeMultipart multipart = new MimeMultipart();
      multipart.setSubType("mixed");
      multipart.addBodyPart(storePart);

      storeMessage.setHeader(MimeHeader.HEADER_CONTENT_TYPE, "multipart/mixed");
      storeMessage.setBody(multipart);

      // 4. Now ask for the attachment to be fetched
      final FetchProfile fp = new FetchProfile();
      fp.add(storePart);
      remoteFolder.fetch(
          new Message[] {storeMessage},
          fp,
          new MessageRetrievalListenerBridge(messageId, attachmentId, cb));

      // If we failed to load the attachment, throw an Exception here, so that
      // AttachmentDownloadService knows that we failed
      if (storePart.getBody() == null) {
        throw new MessagingException("Attachment not loaded.");
      }

      // Save the attachment to wherever it's going
      AttachmentUtilities.saveAttachment(
          mContext, storePart.getBody().getInputStream(), attachment);

      // 6. Report success
      cb.loadAttachmentStatus(messageId, attachmentId, EmailServiceStatus.SUCCESS, 0);

    } catch (MessagingException me) {
      LogUtils.i(Logging.LOG_TAG, me, "Error loading attachment");

      final ContentValues cv = new ContentValues(1);
      cv.put(AttachmentColumns.UI_STATE, UIProvider.AttachmentState.FAILED);
      final Uri uri = ContentUris.withAppendedId(Attachment.CONTENT_URI, attachmentId);
      mContext.getContentResolver().update(uri, cv, null, null);

      cb.loadAttachmentStatus(0, attachmentId, EmailServiceStatus.CONNECTION_ERROR, 0);
    } finally {
      if (remoteFolder != null) {
        remoteFolder.close(false);
      }
    }
  }