def make_release_tree(self, base_dir, files):
        """Create the directory tree that will become the source
        distribution archive.  All directories implied by the filenames in
        'files' are created under 'base_dir', and then we hard link or copy
        (if hard linking is unavailable) those files into place.
        Essentially, this duplicates the developer's source tree, but in a
        directory named after the distribution, containing only the files
        to be distributed.
        """
        # Create all the directories under 'base_dir' necessary to
        # put 'files' there; the 'mkpath()' is just so we don't die
        # if the manifest happens to be empty.
        self.mkpath(base_dir)
        dir_util.create_tree(base_dir, files, dry_run=self.dry_run)

        # And walk over the list of files, either making a hard link (if
        # os.link exists) to each one that doesn't already exist in its
        # corresponding location under 'base_dir', or copying each file
        # that's out-of-date in 'base_dir'.  (Usually, all files will be
        # out-of-date, because by default we blow away 'base_dir' when
        # we're done making the distribution archives.)

        if hasattr(os, 'link'):  # can make hard links on this system
            link = 'hard'
            msg = "making hard links in %s..." % base_dir
        else:  # nope, have to copy
            link = None
            msg = "copying files to %s..." % base_dir

        if not files:
            log.warning("no files to distribute -- empty manifest?")
        else:
            log.info(msg)
        for file in files:
            if not os.path.isfile(file):
                log.warning("'%s' not a regular file -- skipping", file)
            else:
                dest = os.path.join(base_dir, file)
                self.copy_file(file, dest, link=link)

        self.distribution.metadata.write_pkg_info(base_dir)
Create the directory tree that will become the source
        distribution archive.  All directories implied by the filenames in
        'files' are created under 'base_dir', and then we hard link or copy
        (if hard linking is unavailable) those files into place.
        Essentially, this duplicates the developer's source tree, but in a
        directory named after the distribution, containing only the files
        to be distributed.
        
product/gradle-plugin/src/main/python/setuptools/_distutils/command/sdist.py