view hgext/largefiles/wirestore.py @ 27234:15c6eb0a51bd

context: use a the nofsauditor when matching file in history (issue4749)

Before this change, asking for file from history (eg: 'hg cat -r 42 foo/bar')
could fail because of the current content of the working copy (eg: current
"foo" being a symlink). As the working copy state have no influence on the
content of the history, we can safely skip these checks.

The working copy context class have a different 'match'
implementation. That implementation still use the repo.auditor will
still catch symlink traversal.

I've audited all stuff calling "match" and they all go through a ctx
in a sensible way. The most unclear case was diff which still seemed
okay. You raised my paranoid level today and I double checked through
tests. They behave properly.

The odds of someone using the wrong (matching with a changectx for
operation that will eventually touch the file system) is non-zero
because you are never sure of what people will do. But I dunno if we
can fight against that. So I would not commit to "never" for "at this
level" and "in the future" if someone write especially bad code.

However, as a last defense, the vfs itself is running path auditor in
all cases outside of .hg/. So I think anything passing the 'matcher'
for buggy reason would growl at the vfs layer.

# Copyright 2010-2011 Fog Creek Software
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

'''largefile store working over Mercurial's wire protocol'''

import lfutil
import remotestore

class wirestore(remotestore.remotestore):
    def __init__(self, ui, repo, remote):
        cap = remote.capable('largefiles')
        if not cap:
            raise lfutil.storeprotonotcapable([])
        storetypes = cap.split(',')
        if 'serve' not in storetypes:
            raise lfutil.storeprotonotcapable(storetypes)
        self.remote = remote
        super(wirestore, self).__init__(ui, repo, remote.url())

    def _put(self, hash, fd):
        return self.remote.putlfile(hash, fd)

    def _get(self, hash):
        return self.remote.getlfile(hash)

    def _stat(self, hashes):
        '''For each hash, return 0 if it is available, other values if not.
        It is usually 2 if the largefile is missing, but might be 1 the server
        has a corrupted copy.'''
        batch = self.remote.batch()
        futures = {}
        for hash in hashes:
            futures[hash] = batch.statlfile(hash)
        batch.submit()
        retval = {}
        for hash in hashes:
            retval[hash] = futures[hash].value
        return retval