req_install.py 文件源码

def from_editable(cls, editable_req, comes_from=None, default_vcs=None,
                      isolated=False, options=None, wheel_cache=None,
                      constraint=False):
        from pip.index import Link

        name, url, extras_override = parse_editable(
            editable_req, default_vcs)
        if url.startswith('file:'):
            source_dir = url_to_path(url)
        else:
            source_dir = None

        res = cls(name, comes_from, source_dir=source_dir,
                  editable=True,
                  link=Link(url),
                  constraint=constraint,
                  isolated=isolated,
                  options=options if options else {},
                  wheel_cache=wheel_cache)

        if extras_override is not None:
            res.extras = _safe_extras(extras_override)

        return res