mailbox.py 文件源码

def _dump_message(self, message, target, mangle_from_=False):
        # Most files are opened in binary mode to allow predictable seeking.
        # To get native line endings on disk, the user-friendly \n line endings
        # used in strings and by email.Message are translated here.
        """Dump message contents to target file."""
        if isinstance(message, email.message.Message):
            buffer = StringIO.StringIO()
            gen = email.generator.Generator(buffer, mangle_from_, 0)
            gen.flatten(message)
            buffer.seek(0)
            data = buffer.read().replace('\n', os.linesep)
            target.write(data)
            if self._append_newline and not data.endswith(os.linesep):
                # Make sure the message ends with a newline
                target.write(os.linesep)
        elif isinstance(message, str):
            if mangle_from_:
                message = message.replace('\nFrom ', '\n>From ')
            message = message.replace('\n', os.linesep)
            target.write(message)
            if self._append_newline and not message.endswith(os.linesep):
                # Make sure the message ends with a newline
                target.write(os.linesep)
        elif hasattr(message, 'read'):
            lastline = None
            while True:
                line = message.readline()
                if line == '':
                    break
                if mangle_from_ and line.startswith('From '):
                    line = '>From ' + line[5:]
                line = line.replace('\n', os.linesep)
                target.write(line)
                lastline = line
            if self._append_newline and lastline and not lastline.endswith(os.linesep):
                # Make sure the message ends with a newline
                target.write(os.linesep)
        else:
            raise TypeError('Invalid message type: %s' % type(message))