defget_backend_for_scheme(self, scheme: str) -> Optional["VersionControl"]: """ Return a VersionControl object or None. """ for vcs_backend in self._registry.values(): if scheme in vcs_backend.schemes: return vcs_backend returnNone
判断是否有 name 属性，如果没有的话禁止注册，如果有的话，通过 name 属性进行注册，对类进行实例化并且将实例保存到 vcs 的 _registry 字典中。
defdirect_url_from_link( link: Link, source_dir: Optional[str] = None, link_is_in_wheel_cache: bool = False ) -> DirectUrl: if link.is_vcs: vcs_backend = vcs.get_backend_for_scheme(link.scheme) assert vcs_backend url, requested_revision, _ = vcs_backend.get_url_rev_and_auth( link.url_without_fragment ) # For VCS links, we need to find out and add commit_id. if link_is_in_wheel_cache: # If the requested VCS link corresponds to a cached # wheel, it means the requested revision was an # immutable commit hash, otherwise it would not have # been cached. In that case we don't have a source_dir # with the VCS checkout. assert requested_revision commit_id = requested_revision else: # If the wheel was not in cache, it means we have # had to checkout from VCS to build and we have a source_dir # which we can inspect to find out the commit id. assert source_dir commit_id = vcs_backend.get_revision(source_dir) return DirectUrl( url=url, info=VcsInfo( vcs=vcs_backend.name, commit_id=commit_id, requested_revision=requested_revision, ), subdirectory=link.subdirectory_fragment, ) elif link.is_existing_dir(): return DirectUrl( url=link.url_without_fragment, info=DirInfo(), subdirectory=link.subdirectory_fragment, ) else: hash = None hash_name = link.hash_name if hash_name: hash = f"{hash_name}={link.hash}" return DirectUrl( url=link.url_without_fragment, info=ArchiveInfo(hash=hash), subdirectory=link.subdirectory_fragment, )
@classmethod defget_url_rev_and_auth(cls, url: str) -> Tuple[str, Optional[str], AuthInfo]: """ Prefixes stub URLs like 'user@hostname:user/repo.git' with 'ssh://'. That's required because although they use SSH they sometimes don't work with a ssh:// scheme (e.g. GitHub). But we need a scheme for parsing. Hence we remove it again afterwards and return it as a stub. """ # Works around an apparent Git bug # (see https://article.gmane.org/gmane.comp.version-control.git/146500) scheme, netloc, path, query, fragment = urlsplit(url) if scheme.endswith("file"): initial_slashes = path[: -len(path.lstrip("/"))] newpath = initial_slashes + urllib.request.url2pathname(path).replace( "\\", "/" ).lstrip("/") after_plus = scheme.find("+") + 1 url = scheme[:after_plus] + urlunsplit( (scheme[after_plus:], netloc, newpath, query, fragment), )
