Comment 121 for bug 214366

No. The idea here is very similar to the common "priming read" concept taught in introductory CS courses. Following such a pattern the code here should be:

newFolderName.Assign(folderName);
bool containsChild = true;
int counter = 2;

//Priming Read
rv = ContainsChildNamed(newFolderName, &containsChild);
NS_ENSURE_SUCCESS(rv, rv);

while (containsChild) {
  // This could be localizable but Toolkit is fine without it, see
  // mozilla/toolkit/content/contentAreaUtils.js::uniqueFile()
  newFolderName.Assign(folderName);
  newFolderName.AppendLiteral("(");
  newFolderName.AppendInt(i);
  newFolderName.AppendLiteral(")");

  //Read new data
  rv = ContainsChildNamed(newFolderName, &containsChild);
  NS_ENSURE_SUCCESS(rv, rv);
}