view hgext/largefiles/remotestore.py @ 45095:8e04607023e5

procutil: ensure that procutil.std{out,err}.write() writes all bytes

Python 3 offers different kind of streams and it’s not guaranteed for all of
them that calling write() writes all bytes.

When Python is started in unbuffered mode, sys.std{out,err}.buffer are
instances of io.FileIO, whose write() can write less bytes for
platform-specific reasons (e.g. Linux has a 0x7ffff000 bytes maximum and could
write less if interrupted by a signal; when writing to Windows consoles, it’s
limited to 32767 bytes to avoid the "not enough space" error). This can lead to
silent loss of data, both when using sys.std{out,err}.buffer (which may in fact
not be a buffered stream) and when using the text streams sys.std{out,err}
(I’ve created a CPython bug report for that:
https://bugs.python.org/issue41221).

Python may fix the problem at some point. For now, we implement our own wrapper
for procutil.std{out,err} that calls the raw stream’s write() method until all
bytes have been written. We don’t use sys.std{out,err} for larger writes, so I
think it’s not worth the effort to patch them.

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

'''remote largefile store; the base class for wirestore'''
from __future__ import absolute_import

from mercurial.i18n import _

from mercurial import (
    error,
    pycompat,
    util,
)

from mercurial.utils import stringutil

from . import (
    basestore,
    lfutil,
    localstore,
)

urlerr = util.urlerr
urlreq = util.urlreq


class remotestore(basestore.basestore):
    '''a largefile store accessed over a network'''

    def __init__(self, ui, repo, url):
        super(remotestore, self).__init__(ui, repo, url)
        self._lstore = None
        if repo is not None:
            self._lstore = localstore.localstore(self.ui, self.repo, self.repo)

    def put(self, source, hash):
        if self.sendfile(source, hash):
            raise error.Abort(
                _(b'remotestore: could not put %s to remote store %s')
                % (source, util.hidepassword(self.url))
            )
        self.ui.debug(
            _(b'remotestore: put %s to remote store %s\n')
            % (source, util.hidepassword(self.url))
        )

    def exists(self, hashes):
        return {
            h: s == 0
            for (h, s) in pycompat.iteritems(
                self._stat(hashes)
            )  # dict-from-generator
        }

    def sendfile(self, filename, hash):
        self.ui.debug(b'remotestore: sendfile(%s, %s)\n' % (filename, hash))
        try:
            with lfutil.httpsendfile(self.ui, filename) as fd:
                return self._put(hash, fd)
        except IOError as e:
            raise error.Abort(
                _(b'remotestore: could not open file %s: %s')
                % (filename, stringutil.forcebytestr(e))
            )

    def _getfile(self, tmpfile, filename, hash):
        try:
            chunks = self._get(hash)
        except urlerr.httperror as e:
            # 401s get converted to error.Aborts; everything else is fine being
            # turned into a StoreError
            raise basestore.StoreError(
                filename, hash, self.url, stringutil.forcebytestr(e)
            )
        except urlerr.urlerror as e:
            # This usually indicates a connection problem, so don't
            # keep trying with the other files... they will probably
            # all fail too.
            raise error.Abort(
                b'%s: %s' % (util.hidepassword(self.url), e.reason)
            )
        except IOError as e:
            raise basestore.StoreError(
                filename, hash, self.url, stringutil.forcebytestr(e)
            )

        return lfutil.copyandhash(chunks, tmpfile)

    def _hashesavailablelocally(self, hashes):
        existslocallymap = self._lstore.exists(hashes)
        localhashes = [hash for hash in hashes if existslocallymap[hash]]
        return localhashes

    def _verifyfiles(self, contents, filestocheck):
        failed = False
        expectedhashes = [
            expectedhash for cset, filename, expectedhash in filestocheck
        ]
        localhashes = self._hashesavailablelocally(expectedhashes)
        stats = self._stat(
            [
                expectedhash
                for expectedhash in expectedhashes
                if expectedhash not in localhashes
            ]
        )

        for cset, filename, expectedhash in filestocheck:
            if expectedhash in localhashes:
                filetocheck = (cset, filename, expectedhash)
                verifyresult = self._lstore._verifyfiles(
                    contents, [filetocheck]
                )
                if verifyresult:
                    failed = True
            else:
                stat = stats[expectedhash]
                if stat:
                    if stat == 1:
                        self.ui.warn(
                            _(b'changeset %s: %s: contents differ\n')
                            % (cset, filename)
                        )
                        failed = True
                    elif stat == 2:
                        self.ui.warn(
                            _(b'changeset %s: %s missing\n') % (cset, filename)
                        )
                        failed = True
                    else:
                        raise RuntimeError(
                            b'verify failed: unexpected response '
                            b'from statlfile (%r)' % stat
                        )
        return failed

    def _put(self, hash, fd):
        '''Put file with the given hash in the remote store.'''
        raise NotImplementedError(b'abstract method')

    def _get(self, hash):
        '''Get a iterator for content with the given hash.'''
        raise NotImplementedError(b'abstract method')

    def _stat(self, hashes):
        '''Get information about availability of files specified by
        hashes in the remote store. Return dictionary mapping hashes
        to return code where 0 means that file is available, other
        values if not.'''
        raise NotImplementedError(b'abstract method')