saxutils.py 文件源码

def _gettextwriter(out, encoding):
    if out is None:
        import sys
        return sys.stdout

    if isinstance(out, io.TextIOBase):
        # use a text writer as is
        return out

    # wrap a binary writer with TextIOWrapper
    if isinstance(out, io.RawIOBase):
        # Keep the original file open when the TextIOWrapper is
        # destroyed
        class _wrapper:
            __class__ = out.__class__
            def __getattr__(self, name):
                return getattr(out, name)
        buffer = _wrapper()
        buffer.close = lambda: None
    else:
        # This is to handle passed objects that aren't in the
        # IOBase hierarchy, but just have a write method
        buffer = io.BufferedIOBase()
        buffer.writable = lambda: True
        buffer.write = out.write
        try:
            # TextIOWrapper uses this methods to determine
            # if BOM (for UTF-16, etc) should be added
            buffer.seekable = out.seekable
            buffer.tell = out.tell
        except AttributeError:
            pass
    return io.TextIOWrapper(buffer, encoding=encoding,
                            errors='xmlcharrefreplace',
                            newline='\n',
                            write_through=True)