common.py 文件源码

def find_links(file):
    """Find all markdown links in a file object.

    Yield (lineno, regexmatch) tuples.
    """
    # don't yield same link twice
    seen = set()

    # we need to loop over the file two lines at a time to support
    # multi-line (actually two-line) links, so this is kind of a mess
    firsts, seconds = itertools.tee(file)
    next(seconds)  # first line is never second line

    # we want 1-based indexing instead of 0-based and one-line links get
    # caught from linepair[1], so we need to start at two
    for lineno, linepair in enumerate(zip(firsts, seconds), start=2):
        lines = linepair[0] + linepair[1]
        for match in re.finditer(_LINK_REGEX, lines, flags=re.DOTALL):
            if match.group(0) not in seen:
                seen.add(match.group(0))
                yield match, lineno