markdown.py 文件源码

def resolve_url(self, url):
        """
        Resolve internal URLs.

        Returns None if the URL does not need changing, else returns the new URL.
        """
        from markdown.util import AMP_SUBSTITUTE
        if not url:
            return None
        if url.startswith(AMP_SUBSTITUTE):
            # Possibly an overencoded mailto: link.
            # see https://bugs.debian.org/816218
            #
            # Markdown then further escapes & with utils.AMP_SUBSTITUTE, so
            # we look for it here.
            return None
        parsed = urlparse(url)
        if parsed.scheme or parsed.netloc:
            return None
        if not parsed.path:
            return None
        dest = self.page.resolve_link(parsed.path)
        # Also allow .md extension in
        if dest is None and parsed.path.endswith(".md"):
            dirname, basename = os.path.split(parsed.path)
            if basename in ("index.md", "README.md"):
                dest = self.page.resolve_link(dirname)
            else:
                dest = self.page.resolve_link(parsed.path[:-3])
        if dest is None:
            log.warn("%s: internal link %r does not resolve to any site page", self.page.src_relpath, url)
            return None

        return urlunparse(
            (parsed.scheme, parsed.netloc, dest.dst_link, parsed.params, parsed.query, parsed.fragment)
        )