comparison mercurial/util.py @ 22963:56e04741bbf1

util: add a file handle wrapper class that does hash digest validation

It is going to be used for the remote-changegroup feature in bundle2.

22962:4d58f4083148

        for k in DIGESTS_BY_STRENGTH:
            if k in supported:
                return k
        return None

try:
    buffer = buffer
except NameError:
    if sys.version_info[0] < 3:
        def buffer(sliceable, offset=0):

22963:56e04741bbf1

        for k in DIGESTS_BY_STRENGTH:
            if k in supported:
                return k
        return None

class digestchecker(object):
    """file handle wrapper that additionally checks content against a given
    size and digests.

        d = digestchecker(fh, size, {'md5': '...'})

    When multiple digests are given, all of them are validated.
    """

    def __init__(self, fh, size, digests):
        self._fh = fh
        self._size = size
        self._got = 0
        self._digests = dict(digests)
        self._digester = digester(self._digests.keys())

    def read(self, length=-1):
        content = self._fh.read(length)
        self._digester.update(content)
        self._got += len(content)
        return content

    def validate(self):
        if self._size != self._got:
            raise Abort(_('size mismatch: expected %d, got %d') %
                (self._size, self._got))
        for k, v in self._digests.items():
            if v != self._digester[k]:
                raise Abort(_('%s mismatch: expected %s, got %s') %
                    (k, v, self._digester[k]))

try:
    buffer = buffer
except NameError:
    if sys.version_info[0] < 3:
        def buffer(sliceable, offset=0):