if (!mElement) { return NS_OK; }
nsXFormsLabelElement::OnDataAvailable(nsIRequest *aRequest,                                      nsISupports *aContext,                                      nsIInputStream *aInputStream,                                      PRUint32 aOffset,                                      PRUint32 aCount){  nsresult rv;  PRUint32 size, bytesRead;  char buffer[256];  while (aCount) {    size = PR_MIN(aCount, sizeof(buffer));    rv = aInputStream->Read(buffer, size, &bytesRead);    if (NS_FAILED(rv))      return rv;    mSrcAttrText.Append(buffer, bytesRead);    aCount -= bytesRead;  }  return NS_OK;}