view hgext/lfs/pointer.py @ 49487:e8481625c582

rust: add Debug constraint to Matcher trait

This makes sure we can easily debug which Matcher we're looking at when using
trait objects, and is just generally useful. Effort to make the debugging
output nicer has been kept to a minimum, please feel free to improve.

# pointer.py - Git-LFS pointer serialization
#
# Copyright 2017 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.


import re

from mercurial.i18n import _

from mercurial import (
    error,
    pycompat,
)
from mercurial.utils import stringutil


class InvalidPointer(error.StorageError):
    pass


class gitlfspointer(dict):
    VERSION = b'https://git-lfs.github.com/spec/v1'

    def __init__(self, *args, **kwargs):
        self[b'version'] = self.VERSION
        super(gitlfspointer, self).__init__(*args)
        self.update(pycompat.byteskwargs(kwargs))

    @classmethod
    def deserialize(cls, text):
        try:
            return cls(l.split(b' ', 1) for l in text.splitlines()).validate()
        except ValueError:  # l.split returns 1 item instead of 2
            raise InvalidPointer(
                _(b'cannot parse git-lfs text: %s') % stringutil.pprint(text)
            )

    def serialize(self):
        sortkeyfunc = lambda x: (x[0] != b'version', x)
        items = sorted(self.validate().items(), key=sortkeyfunc)
        return b''.join(b'%s %s\n' % (k, v) for k, v in items)

    def oid(self):
        return self[b'oid'].split(b':')[-1]

    def size(self):
        return int(self[b'size'])

    # regular expressions used by _validate
    # see https://github.com/git-lfs/git-lfs/blob/master/docs/spec.md
    _keyre = re.compile(br'\A[a-z0-9.-]+\Z')
    _valuere = re.compile(br'\A[^\n]*\Z')
    _requiredre = {
        b'size': re.compile(br'\A[0-9]+\Z'),
        b'oid': re.compile(br'\Asha256:[0-9a-f]{64}\Z'),
        b'version': re.compile(br'\A%s\Z' % stringutil.reescape(VERSION)),
    }

    def validate(self):
        """raise InvalidPointer on error. return self if there is no error"""
        requiredcount = 0
        for k, v in self.items():
            if k in self._requiredre:
                if not self._requiredre[k].match(v):
                    raise InvalidPointer(
                        _(b'unexpected lfs pointer value: %s=%s')
                        % (k, stringutil.pprint(v))
                    )
                requiredcount += 1
            elif not self._keyre.match(k):
                raise InvalidPointer(_(b'unexpected lfs pointer key: %s') % k)
            if not self._valuere.match(v):
                raise InvalidPointer(
                    _(b'unexpected lfs pointer value: %s=%s')
                    % (k, stringutil.pprint(v))
                )
        if len(self._requiredre) != requiredcount:
            miss = sorted(set(self._requiredre.keys()).difference(self.keys()))
            raise InvalidPointer(
                _(b'missing lfs pointer keys: %s') % b', '.join(miss)
            )
        return self


deserialize = gitlfspointer.deserialize