streamclone: define first iteration of version 2 of stream format
(This patch is based on a first draft from Gregory Szorc, with deeper rework)
Version 1 of the stream clone format was invented many years ago and suffers
from a few deficiencies:
1) Filenames are stored in store-encoded (on filesystem) form rather than in
their internal form. This makes future compatibility with new store
filename encodings more difficult.
2) File entry "headers" consist of a newline of the file name followed by the
string file size. Converting strings to integers is avoidable overhead. We
can't store filenames with newlines (manifests have this limitation as
well, so it isn't a major concern). But the big concern here is the
necessity for readline(). Scanning for newlines means reading ahead and
that means extra buffer allocations and slicing (in Python) and this makes
performance suffer.
3) Filenames aren't compressed optimally. Filenames should be compressed well
since there is a lot of repeated data. However, since they are scattered
all over the stream (with revlog data in between), they typically fall
outside the window size of the compressor and don't compress.
4) It can only exchange stored based content, being able to exchange caches
too would be nice.
5) It is limited to a stream-based protocol and isn't suitable for an on-disk
format for general repository reading because the offset of individual file
entries requires scanning the entire file to find file records.
As part of enabling streaming clones to work in bundle2, #2 proved to have a
significant negative impact on performance. Since bundle2 provides the
opportunity to start fresh, Gregory Szorc figured he would take the
opportunity to invent a new streaming clone data format.
The new format devised in this series addresses #1, #2, and #4. It punts on #3
because it was complex without yielding a significant gain and on #5 because
devising a new store format that "packs" multiple revlogs into a single
"packed revlog" is massive scope bloat. However, this v2 format might be
suitable for streaming into a "packed revlog" with minimal processing. If it
works, great. If not, we can always invent stream format when it is needed.
This patch only introduces the bases of the format. We'll get it usable through
bundle2 first, then we'll extend the format in future patches to bring it to its
full potential (especially #4).
# Since it's not easy to write a test that portably deals
# with files from different users/groups, we cheat a bit by
# monkey-patching some functions in the util module
from __future__ import absolute_import, print_function
import os
from mercurial import (
error,
ui as uimod,
util,
)
hgrc = os.environ['HGRCPATH']
f = open(hgrc)
basehgrc = f.read()
f.close()
def testui(user='foo', group='bar', tusers=(), tgroups=(),
cuser='foo', cgroup='bar', debug=False, silent=False,
report=True):
# user, group => owners of the file
# tusers, tgroups => trusted users/groups
# cuser, cgroup => user/group of the current process
# write a global hgrc with the list of trusted users/groups and
# some setting so that we can be sure it was read
f = open(hgrc, 'w')
f.write(basehgrc)
f.write('\n[paths]\n')
f.write('global = /some/path\n\n')
if tusers or tgroups:
f.write('[trusted]\n')
if tusers:
f.write('users = %s\n' % ', '.join(tusers))
if tgroups:
f.write('groups = %s\n' % ', '.join(tgroups))
f.close()
# override the functions that give names to uids and gids
def username(uid=None):
if uid is None:
return cuser
return user
util.username = username
def groupname(gid=None):
if gid is None:
return 'bar'
return group
util.groupname = groupname
def isowner(st):
return user == cuser
util.isowner = isowner
# try to read everything
#print '# File belongs to user %s, group %s' % (user, group)
#print '# trusted users = %s; trusted groups = %s' % (tusers, tgroups)
kind = ('different', 'same')
who = ('', 'user', 'group', 'user and the group')
trusted = who[(user in tusers) + 2*(group in tgroups)]
if trusted:
trusted = ', but we trust the ' + trusted
print('# %s user, %s group%s' % (kind[user == cuser], kind[group == cgroup],
trusted))
u = uimod.ui.load()
# disable the configuration registration warning
#
# the purpose of this test is to check the old behavior, not to validate the
# behavior from registered item. so we silent warning related to unregisted
# config.
u.setconfig('devel', 'warn-config-unknown', False, 'test')
u.setconfig('devel', 'all-warnings', False, 'test')
u.setconfig('ui', 'debug', str(bool(debug)))
u.setconfig('ui', 'report_untrusted', str(bool(report)))
u.readconfig('.hg/hgrc')
if silent:
return u
print('trusted')
for name, path in u.configitems('paths'):
print(' ', name, '=', util.pconvert(path))
print('untrusted')
for name, path in u.configitems('paths', untrusted=True):
print('.', end=' ')
u.config('paths', name) # warning with debug=True
print('.', end=' ')
u.config('paths', name, untrusted=True) # no warnings
print(name, '=', util.pconvert(path))
print()
return u
os.mkdir('repo')
os.chdir('repo')
os.mkdir('.hg')
f = open('.hg/hgrc', 'w')
f.write('[paths]\n')
f.write('local = /another/path\n\n')
f.close()
#print '# Everything is run by user foo, group bar\n'
# same user, same group
testui()
# same user, different group
testui(group='def')
# different user, same group
testui(user='abc')
# ... but we trust the group
testui(user='abc', tgroups=['bar'])
# different user, different group
testui(user='abc', group='def')
# ... but we trust the user
testui(user='abc', group='def', tusers=['abc'])
# ... but we trust the group
testui(user='abc', group='def', tgroups=['def'])
# ... but we trust the user and the group
testui(user='abc', group='def', tusers=['abc'], tgroups=['def'])
# ... but we trust all users
print('# we trust all users')
testui(user='abc', group='def', tusers=['*'])
# ... but we trust all groups
print('# we trust all groups')
testui(user='abc', group='def', tgroups=['*'])
# ... but we trust the whole universe
print('# we trust all users and groups')
testui(user='abc', group='def', tusers=['*'], tgroups=['*'])
# ... check that users and groups are in different namespaces
print("# we don't get confused by users and groups with the same name")
testui(user='abc', group='def', tusers=['def'], tgroups=['abc'])
# ... lists of user names work
print("# list of user names")
testui(user='abc', group='def', tusers=['foo', 'xyz', 'abc', 'bleh'],
tgroups=['bar', 'baz', 'qux'])
# ... lists of group names work
print("# list of group names")
testui(user='abc', group='def', tusers=['foo', 'xyz', 'bleh'],
tgroups=['bar', 'def', 'baz', 'qux'])
print("# Can't figure out the name of the user running this process")
testui(user='abc', group='def', cuser=None)
print("# prints debug warnings")
u = testui(user='abc', group='def', cuser='foo', debug=True)
print("# report_untrusted enabled without debug hides warnings")
u = testui(user='abc', group='def', cuser='foo', report=False)
print("# report_untrusted enabled with debug shows warnings")
u = testui(user='abc', group='def', cuser='foo', debug=True, report=False)
print("# ui.readconfig sections")
filename = 'foobar'
f = open(filename, 'w')
f.write('[foobar]\n')
f.write('baz = quux\n')
f.close()
u.readconfig(filename, sections=['foobar'])
print(u.config('foobar', 'baz'))
print()
print("# read trusted, untrusted, new ui, trusted")
u = uimod.ui.load()
# disable the configuration registration warning
#
# the purpose of this test is to check the old behavior, not to validate the
# behavior from registered item. so we silent warning related to unregisted
# config.
u.setconfig('devel', 'warn-config-unknown', False, 'test')
u.setconfig('devel', 'all-warnings', False, 'test')
u.setconfig('ui', 'debug', 'on')
u.readconfig(filename)
u2 = u.copy()
def username(uid=None):
return 'foo'
util.username = username
u2.readconfig('.hg/hgrc')
print('trusted:')
print(u2.config('foobar', 'baz'))
print('untrusted:')
print(u2.config('foobar', 'baz', untrusted=True))
print()
print("# error handling")
def assertraises(f, exc=error.Abort):
try:
f()
except exc as inst:
print('raised', inst.__class__.__name__)
else:
print('no exception?!')
print("# file doesn't exist")
os.unlink('.hg/hgrc')
assert not os.path.exists('.hg/hgrc')
testui(debug=True, silent=True)
testui(user='abc', group='def', debug=True, silent=True)
print()
print("# parse error")
f = open('.hg/hgrc', 'w')
f.write('foo')
f.close()
try:
testui(user='abc', group='def', silent=True)
except error.ParseError as inst:
print(inst)
try:
testui(debug=True, silent=True)
except error.ParseError as inst:
print(inst)
print()
print('# access typed information')
with open('.hg/hgrc', 'w') as f:
f.write('''\
[foo]
sub=main
sub:one=one
sub:two=two
path=monty/python
bool=true
int=42
bytes=81mb
list=spam,ham,eggs
''')
u = testui(user='abc', group='def', cuser='foo', silent=True)
def configpath(section, name, default=None, untrusted=False):
path = u.configpath(section, name, default, untrusted)
if path is None:
return None
return util.pconvert(path)
print('# suboptions, trusted and untrusted')
trusted = u.configsuboptions('foo', 'sub')
untrusted = u.configsuboptions('foo', 'sub', untrusted=True)
print(
(trusted[0], sorted(trusted[1].items())),
(untrusted[0], sorted(untrusted[1].items())))
print('# path, trusted and untrusted')
print(configpath('foo', 'path'), configpath('foo', 'path', untrusted=True))
print('# bool, trusted and untrusted')
print(u.configbool('foo', 'bool'), u.configbool('foo', 'bool', untrusted=True))
print('# int, trusted and untrusted')
print(
u.configint('foo', 'int', 0),
u.configint('foo', 'int', 0, untrusted=True))
print('# bytes, trusted and untrusted')
print(
u.configbytes('foo', 'bytes', 0),
u.configbytes('foo', 'bytes', 0, untrusted=True))
print('# list, trusted and untrusted')
print(
u.configlist('foo', 'list', []),
u.configlist('foo', 'list', [], untrusted=True))