procutil: make stream detection in make_line_buffered more correct and strict
In make_line_buffered(), we don’t want to wrap the stream if we know that lines
get flushed to the underlying raw stream already.
Previously, the heuristic was too optimistic. It assumed that any stream which
is not an instance of io.BufferedIOBase doesn’t need wrapping. However, there
are buffered streams that aren’t instances of io.BufferedIOBase, like
Mercurial’s own winstdout.
The new logic is different in two ways:
First, only for the check, if unwraps any combination of WriteAllWrapper and
winstdout.
Second, it skips wrapping the stream only if it is an instance of io.RawIOBase
(or already wrapped). If it is an instance of io.BufferedIOBase, it gets
wrapped. In any other case, the function raises an exception. This ensures
that, if an unknown stream is passed or we add another wrapper in the future,
we don’t wrap the stream if it’s already line buffered or not wrap the stream
if it’s not line buffered. In fact, this was already helpful during development
of this change. Without it, I possibly would have forgot that WriteAllWrapper
needs to be ignored for the check, leading to unnecessary wrapping if stdout is
unbuffered.
The alternative would have been to always wrap unknown streams. However, I
don’t think that anyone would benefit from being less strict. We can expect
streams from the standard library to be subclassing either io.RawIOBase or
io.BufferedIOBase, so running Mercurial in the standard way should not regress
by this change. Py2exe might replace sys.stdout and sys.stderr, but that
currently breaks Mercurial anyway and also these streams don’t claim to be
interactive, so this function is not called for them.
# Copyright 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.
import os
from mercurial.i18n import _
from mercurial.pycompat import open
from mercurial import (
error,
exthelper,
httppeer,
util,
wireprototypes,
wireprotov1peer,
wireprotov1server,
)
from . import lfutil
urlerr = util.urlerr
urlreq = util.urlreq
LARGEFILES_REQUIRED_MSG = (
b'\nThis repository uses the largefiles extension.'
b'\n\nPlease enable it in your Mercurial config '
b'file.\n'
)
eh = exthelper.exthelper()
def putlfile(repo, proto, sha):
"""Server command for putting a largefile into a repository's local store
and into the user cache."""
with proto.mayberedirectstdio() as output:
path = lfutil.storepath(repo, sha)
util.makedirs(os.path.dirname(path))
tmpfp = util.atomictempfile(path, createmode=repo.store.createmode)
try:
for p in proto.getpayload():
tmpfp.write(p)
tmpfp._fp.seek(0)
if sha != lfutil.hexsha1(tmpfp._fp):
raise IOError(0, _(b'largefile contents do not match hash'))
tmpfp.close()
lfutil.linktousercache(repo, sha)
except IOError as e:
repo.ui.warn(
_(b'largefiles: failed to put %s into store: %s\n')
% (sha, e.strerror)
)
return wireprototypes.pushres(
1, output.getvalue() if output else b''
)
finally:
tmpfp.discard()
return wireprototypes.pushres(0, output.getvalue() if output else b'')
def getlfile(repo, proto, sha):
"""Server command for retrieving a largefile from the repository-local
cache or user cache."""
filename = lfutil.findfile(repo, sha)
if not filename:
raise error.Abort(
_(b'requested largefile %s not present in cache') % sha
)
f = open(filename, b'rb')
length = os.fstat(f.fileno())[6]
# Since we can't set an HTTP content-length header here, and
# Mercurial core provides no way to give the length of a streamres
# (and reading the entire file into RAM would be ill-advised), we
# just send the length on the first line of the response, like the
# ssh proto does for string responses.
def generator():
yield b'%d\n' % length
for chunk in util.filechunkiter(f):
yield chunk
return wireprototypes.streamreslegacy(gen=generator())
def statlfile(repo, proto, sha):
"""Server command for checking if a largefile is present - returns '2\n' if
the largefile is missing, '0\n' if it seems to be in good condition.
The value 1 is reserved for mismatched checksum, but that is too expensive
to be verified on every stat and must be caught be running 'hg verify'
server side."""
filename = lfutil.findfile(repo, sha)
if not filename:
return wireprototypes.bytesresponse(b'2\n')
return wireprototypes.bytesresponse(b'0\n')
def wirereposetup(ui, repo):
orig_commandexecutor = repo.commandexecutor
class lfileswirerepository(repo.__class__):
def commandexecutor(self):
executor = orig_commandexecutor()
if self.capable(b'largefiles'):
orig_callcommand = executor.callcommand
class lfscommandexecutor(executor.__class__):
def callcommand(self, command, args):
if command == b'heads':
command = b'lheads'
return orig_callcommand(command, args)
executor.__class__ = lfscommandexecutor
return executor
@wireprotov1peer.batchable
def lheads(self):
return self.heads.batchable(self)
def putlfile(self, sha, fd):
# unfortunately, httprepository._callpush tries to convert its
# input file-like into a bundle before sending it, so we can't use
# it ...
if issubclass(self.__class__, httppeer.httppeer):
res = self._call(
b'putlfile',
data=fd,
sha=sha,
headers={'content-type': 'application/mercurial-0.1'},
)
try:
d, output = res.split(b'\n', 1)
for l in output.splitlines(True):
self.ui.warn(_(b'remote: '), l) # assume l ends with \n
return int(d)
except ValueError:
self.ui.warn(_(b'unexpected putlfile response: %r\n') % res)
return 1
# ... but we can't use sshrepository._call because the data=
# argument won't get sent, and _callpush does exactly what we want
# in this case: send the data straight through
else:
try:
ret, output = self._callpush(b"putlfile", fd, sha=sha)
if ret == b"":
raise error.ResponseError(
_(b'putlfile failed:'), output
)
return int(ret)
except IOError:
return 1
except ValueError:
raise error.ResponseError(
_(b'putlfile failed (unexpected response):'), ret
)
def getlfile(self, sha):
"""returns an iterable with the chunks of the file with sha sha"""
stream = self._callstream(b"getlfile", sha=sha)
length = stream.readline()
try:
length = int(length)
except ValueError:
self._abort(
error.ResponseError(_(b"unexpected response:"), length)
)
# SSH streams will block if reading more than length
for chunk in util.filechunkiter(stream, limit=length):
yield chunk
# HTTP streams must hit the end to process the last empty
# chunk of Chunked-Encoding so the connection can be reused.
if issubclass(self.__class__, httppeer.httppeer):
chunk = stream.read(1)
if chunk:
self._abort(
error.ResponseError(_(b"unexpected response:"), chunk)
)
@wireprotov1peer.batchable
def statlfile(self, sha):
def decode(d):
try:
return int(d)
except (ValueError, urlerr.httperror):
# If the server returns anything but an integer followed by a
# newline, newline, it's not speaking our language; if we get
# an HTTP error, we can't be sure the largefile is present;
# either way, consider it missing.
return 2
result = {b'sha': sha}
return result, decode
repo.__class__ = lfileswirerepository
# advertise the largefiles=serve capability
@eh.wrapfunction(wireprotov1server, b'_capabilities')
def _capabilities(orig, repo, proto):
'''announce largefile server capability'''
caps = orig(repo, proto)
caps.append(b'largefiles=serve')
return caps
def heads(orig, repo, proto):
"""Wrap server command - largefile capable clients will know to call
lheads instead"""
if lfutil.islfilesrepo(repo):
return wireprototypes.ooberror(LARGEFILES_REQUIRED_MSG)
return orig(repo, proto)