Show results when diff option on.

def showDiffResults(self):
        """
        Show results when diff option on.
        """
        try:
            oldWarnings = self.parseWarnings(self._readDiffFile())
        except:
            sys.stderr.write(self.errorResultRead % self.diffOption)
            return 1

        newWarnings = self.parseWarnings(self.streamForDiff.getvalue())

        diffWarnings = self.generateDiff(oldWarnings, newWarnings)

        if diffWarnings:
            diffResult = self.formatWarnings(diffWarnings)
            self.outputStream.write(diffResult + "\n")
            return len(diffWarnings)
        else:
            return 0