protocol: send application/mercurial-0.2 responses to capable clients
With this commit, the HTTP transport now parses the X-HgProto-<N>
header to determine what media type and compression engine to use for
responses. So far, we only compress responses that are already being
compressed with zlib today (stream response types to specific
commands). We can expand things to cover additional response types
later.
The practical side-effect of this commit is that non-zlib compression
engines will be used if both ends support them. This means if both
ends have zstd support, zstd - not zlib - will be used to compress
data!
When cloning the mozilla-unified repository between a local HTTP
server and client, the benefits of non-zlib compression are quite
noticeable:
engine server CPU (s) client CPU (s) bundle size
zlib (l=6) 174.1 283.2 1,148,547,026
zstd (l=1) 99.2 267.3 1,127,513,841
zstd (l=3) 103.1 266.9 1,018,861,363
zstd (l=7) 128.3 269.7 919,190,278
zstd (l=10) 162.0 - 894,547,179
none 95.3 277.2 4,097,566,064
The default zstd compression level is 3. So if you deploy zstd
capable Mercurial to your clients and servers and CPU time on
your server is dominated by "getbundle" requests (clients cloning
and pulling) - and my experience at Mozilla tells me this is often
the case - this commit could drastically reduce your server-side
CPU usage *and* save on bandwidth costs!
Another benefit of this change is that server operators can install
*any* compression engine. While it isn't enabled by default, the
"none" compression engine can now be used to disable wire protocol
compression completely. Previously, commands like "getbundle" always
zlib compressed output, adding considerable overhead to generating
responses. If you are on a high speed network and your server is under
high load, it might be advantageous to trade bandwidth for CPU.
Although, zstd at level 1 doesn't use that much CPU, so I'm not
convinced that disabling compression wholesale is worthwhile. And, my
data seems to indicate a slow down on the client without compression.
I suspect this is due to a lack of buffering resulting in an increase
in socket read() calls and/or the fact we're transferring an extra 3 GB
of data (parsing HTTP chunked transfer and processing extra TCP packets
can add up). This is definitely worth investigating and optimizing. But
since the "none" compressor isn't enabled by default, I'm inclined to
punt on this issue.
This commit introduces tons of tests. Some of these should arguably
have been implemented on previous commits. But it was difficult to
test without the server functionality in place.
# store.py - repository store handling for Mercurial
#
# Copyright 2008 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import absolute_import
import errno
import hashlib
import os
import stat
from .i18n import _
from . import (
error,
parsers,
pycompat,
scmutil,
util,
)
# This avoids a collision between a file named foo and a dir named
# foo.i or foo.d
def _encodedir(path):
'''
>>> _encodedir('data/foo.i')
'data/foo.i'
>>> _encodedir('data/foo.i/bla.i')
'data/foo.i.hg/bla.i'
>>> _encodedir('data/foo.i.hg/bla.i')
'data/foo.i.hg.hg/bla.i'
>>> _encodedir('data/foo.i\\ndata/foo.i/bla.i\\ndata/foo.i.hg/bla.i\\n')
'data/foo.i\\ndata/foo.i.hg/bla.i\\ndata/foo.i.hg.hg/bla.i\\n'
'''
return (path
.replace(".hg/", ".hg.hg/")
.replace(".i/", ".i.hg/")
.replace(".d/", ".d.hg/"))
encodedir = getattr(parsers, 'encodedir', _encodedir)
def decodedir(path):
'''
>>> decodedir('data/foo.i')
'data/foo.i'
>>> decodedir('data/foo.i.hg/bla.i')
'data/foo.i/bla.i'
>>> decodedir('data/foo.i.hg.hg/bla.i')
'data/foo.i.hg/bla.i'
'''
if ".hg/" not in path:
return path
return (path
.replace(".d.hg/", ".d/")
.replace(".i.hg/", ".i/")
.replace(".hg.hg/", ".hg/"))
def _reserved():
''' characters that are problematic for filesystems
* ascii escapes (0..31)
* ascii hi (126..255)
* windows specials
these characters will be escaped by encodefunctions
'''
winreserved = [ord(x) for x in u'\\:*?"<>|']
for x in range(32):
yield x
for x in range(126, 256):
yield x
for x in winreserved:
yield x
def _buildencodefun():
'''
>>> enc, dec = _buildencodefun()
>>> enc('nothing/special.txt')
'nothing/special.txt'
>>> dec('nothing/special.txt')
'nothing/special.txt'
>>> enc('HELLO')
'_h_e_l_l_o'
>>> dec('_h_e_l_l_o')
'HELLO'
>>> enc('hello:world?')
'hello~3aworld~3f'
>>> dec('hello~3aworld~3f')
'hello:world?'
>>> enc('the\x07quick\xADshot')
'the~07quick~adshot'
>>> dec('the~07quick~adshot')
'the\\x07quick\\xadshot'
'''
e = '_'
if pycompat.ispy3:
xchr = lambda x: bytes([x])
asciistr = bytes(xrange(127))
else:
xchr = chr
asciistr = map(chr, xrange(127))
capitals = list(range(ord("A"), ord("Z") + 1))
cmap = dict((x, x) for x in asciistr)
for x in _reserved():
cmap[xchr(x)] = "~%02x" % x
for x in capitals + [ord(e)]:
cmap[xchr(x)] = e + xchr(x).lower()
dmap = {}
for k, v in cmap.iteritems():
dmap[v] = k
def decode(s):
i = 0
while i < len(s):
for l in xrange(1, 4):
try:
yield dmap[s[i:i + l]]
i += l
break
except KeyError:
pass
else:
raise KeyError
return (lambda s: ''.join([cmap[c] for c in s]),
lambda s: ''.join(list(decode(s))))
_encodefname, _decodefname = _buildencodefun()
def encodefilename(s):
'''
>>> encodefilename('foo.i/bar.d/bla.hg/hi:world?/HELLO')
'foo.i.hg/bar.d.hg/bla.hg.hg/hi~3aworld~3f/_h_e_l_l_o'
'''
return _encodefname(encodedir(s))
def decodefilename(s):
'''
>>> decodefilename('foo.i.hg/bar.d.hg/bla.hg.hg/hi~3aworld~3f/_h_e_l_l_o')
'foo.i/bar.d/bla.hg/hi:world?/HELLO'
'''
return decodedir(_decodefname(s))
def _buildlowerencodefun():
'''
>>> f = _buildlowerencodefun()
>>> f('nothing/special.txt')
'nothing/special.txt'
>>> f('HELLO')
'hello'
>>> f('hello:world?')
'hello~3aworld~3f'
>>> f('the\x07quick\xADshot')
'the~07quick~adshot'
'''
cmap = dict([(chr(x), chr(x)) for x in xrange(127)])
for x in _reserved():
cmap[chr(x)] = "~%02x" % x
for x in range(ord("A"), ord("Z") + 1):
cmap[chr(x)] = chr(x).lower()
return lambda s: "".join([cmap[c] for c in s])
lowerencode = getattr(parsers, 'lowerencode', None) or _buildlowerencodefun()
# Windows reserved names: con, prn, aux, nul, com1..com9, lpt1..lpt9
_winres3 = ('aux', 'con', 'prn', 'nul') # length 3
_winres4 = ('com', 'lpt') # length 4 (with trailing 1..9)
def _auxencode(path, dotencode):
'''
Encodes filenames containing names reserved by Windows or which end in
period or space. Does not touch other single reserved characters c.
Specifically, c in '\\:*?"<>|' or ord(c) <= 31 are *not* encoded here.
Additionally encodes space or period at the beginning, if dotencode is
True. Parameter path is assumed to be all lowercase.
A segment only needs encoding if a reserved name appears as a
basename (e.g. "aux", "aux.foo"). A directory or file named "foo.aux"
doesn't need encoding.
>>> s = '.foo/aux.txt/txt.aux/con/prn/nul/foo.'
>>> _auxencode(s.split('/'), True)
['~2efoo', 'au~78.txt', 'txt.aux', 'co~6e', 'pr~6e', 'nu~6c', 'foo~2e']
>>> s = '.com1com2/lpt9.lpt4.lpt1/conprn/com0/lpt0/foo.'
>>> _auxencode(s.split('/'), False)
['.com1com2', 'lp~749.lpt4.lpt1', 'conprn', 'com0', 'lpt0', 'foo~2e']
>>> _auxencode(['foo. '], True)
['foo.~20']
>>> _auxencode([' .foo'], True)
['~20.foo']
'''
for i, n in enumerate(path):
if not n:
continue
if dotencode and n[0] in '. ':
n = "~%02x" % ord(n[0]) + n[1:]
path[i] = n
else:
l = n.find('.')
if l == -1:
l = len(n)
if ((l == 3 and n[:3] in _winres3) or
(l == 4 and n[3] <= '9' and n[3] >= '1'
and n[:3] in _winres4)):
# encode third letter ('aux' -> 'au~78')
ec = "~%02x" % ord(n[2])
n = n[0:2] + ec + n[3:]
path[i] = n
if n[-1] in '. ':
# encode last period or space ('foo...' -> 'foo..~2e')
path[i] = n[:-1] + "~%02x" % ord(n[-1])
return path
_maxstorepathlen = 120
_dirprefixlen = 8
_maxshortdirslen = 8 * (_dirprefixlen + 1) - 4
def _hashencode(path, dotencode):
digest = hashlib.sha1(path).hexdigest()
le = lowerencode(path[5:]).split('/') # skips prefix 'data/' or 'meta/'
parts = _auxencode(le, dotencode)
basename = parts[-1]
_root, ext = os.path.splitext(basename)
sdirs = []
sdirslen = 0
for p in parts[:-1]:
d = p[:_dirprefixlen]
if d[-1] in '. ':
# Windows can't access dirs ending in period or space
d = d[:-1] + '_'
if sdirslen == 0:
t = len(d)
else:
t = sdirslen + 1 + len(d)
if t > _maxshortdirslen:
break
sdirs.append(d)
sdirslen = t
dirs = '/'.join(sdirs)
if len(dirs) > 0:
dirs += '/'
res = 'dh/' + dirs + digest + ext
spaceleft = _maxstorepathlen - len(res)
if spaceleft > 0:
filler = basename[:spaceleft]
res = 'dh/' + dirs + filler + digest + ext
return res
def _hybridencode(path, dotencode):
'''encodes path with a length limit
Encodes all paths that begin with 'data/', according to the following.
Default encoding (reversible):
Encodes all uppercase letters 'X' as '_x'. All reserved or illegal
characters are encoded as '~xx', where xx is the two digit hex code
of the character (see encodefilename).
Relevant path components consisting of Windows reserved filenames are
masked by encoding the third character ('aux' -> 'au~78', see _auxencode).
Hashed encoding (not reversible):
If the default-encoded path is longer than _maxstorepathlen, a
non-reversible hybrid hashing of the path is done instead.
This encoding uses up to _dirprefixlen characters of all directory
levels of the lowerencoded path, but not more levels than can fit into
_maxshortdirslen.
Then follows the filler followed by the sha digest of the full path.
The filler is the beginning of the basename of the lowerencoded path
(the basename is everything after the last path separator). The filler
is as long as possible, filling in characters from the basename until
the encoded path has _maxstorepathlen characters (or all chars of the
basename have been taken).
The extension (e.g. '.i' or '.d') is preserved.
The string 'data/' at the beginning is replaced with 'dh/', if the hashed
encoding was used.
'''
path = encodedir(path)
ef = _encodefname(path).split('/')
res = '/'.join(_auxencode(ef, dotencode))
if len(res) > _maxstorepathlen:
res = _hashencode(path, dotencode)
return res
def _pathencode(path):
de = encodedir(path)
if len(path) > _maxstorepathlen:
return _hashencode(de, True)
ef = _encodefname(de).split('/')
res = '/'.join(_auxencode(ef, True))
if len(res) > _maxstorepathlen:
return _hashencode(de, True)
return res
_pathencode = getattr(parsers, 'pathencode', _pathencode)
def _plainhybridencode(f):
return _hybridencode(f, False)
def _calcmode(vfs):
try:
# files in .hg/ will be created using this mode
mode = vfs.stat().st_mode
# avoid some useless chmods
if (0o777 & ~util.umask) == (0o777 & mode):
mode = None
except OSError:
mode = None
return mode
_data = ('data meta 00manifest.d 00manifest.i 00changelog.d 00changelog.i'
' phaseroots obsstore')
class basicstore(object):
'''base class for local repository stores'''
def __init__(self, path, vfstype):
vfs = vfstype(path)
self.path = vfs.base
self.createmode = _calcmode(vfs)
vfs.createmode = self.createmode
self.rawvfs = vfs
self.vfs = scmutil.filtervfs(vfs, encodedir)
self.opener = self.vfs
def join(self, f):
return self.path + '/' + encodedir(f)
def _walk(self, relpath, recurse):
'''yields (unencoded, encoded, size)'''
path = self.path
if relpath:
path += '/' + relpath
striplen = len(self.path) + 1
l = []
if self.rawvfs.isdir(path):
visit = [path]
readdir = self.rawvfs.readdir
while visit:
p = visit.pop()
for f, kind, st in readdir(p, stat=True):
fp = p + '/' + f
if kind == stat.S_IFREG and f[-2:] in ('.d', '.i'):
n = util.pconvert(fp[striplen:])
l.append((decodedir(n), n, st.st_size))
elif kind == stat.S_IFDIR and recurse:
visit.append(fp)
l.sort()
return l
def datafiles(self):
return self._walk('data', True) + self._walk('meta', True)
def topfiles(self):
# yield manifest before changelog
return reversed(self._walk('', False))
def walk(self):
'''yields (unencoded, encoded, size)'''
# yield data files first
for x in self.datafiles():
yield x
for x in self.topfiles():
yield x
def copylist(self):
return ['requires'] + _data.split()
def write(self, tr):
pass
def invalidatecaches(self):
pass
def markremoved(self, fn):
pass
def __contains__(self, path):
'''Checks if the store contains path'''
path = "/".join(("data", path))
# file?
if self.vfs.exists(path + ".i"):
return True
# dir?
if not path.endswith("/"):
path = path + "/"
return self.vfs.exists(path)
class encodedstore(basicstore):
def __init__(self, path, vfstype):
vfs = vfstype(path + '/store')
self.path = vfs.base
self.createmode = _calcmode(vfs)
vfs.createmode = self.createmode
self.rawvfs = vfs
self.vfs = scmutil.filtervfs(vfs, encodefilename)
self.opener = self.vfs
def datafiles(self):
for a, b, size in super(encodedstore, self).datafiles():
try:
a = decodefilename(a)
except KeyError:
a = None
yield a, b, size
def join(self, f):
return self.path + '/' + encodefilename(f)
def copylist(self):
return (['requires', '00changelog.i'] +
['store/' + f for f in _data.split()])
class fncache(object):
# the filename used to be partially encoded
# hence the encodedir/decodedir dance
def __init__(self, vfs):
self.vfs = vfs
self.entries = None
self._dirty = False
def _load(self):
'''fill the entries from the fncache file'''
self._dirty = False
try:
fp = self.vfs('fncache', mode='rb')
except IOError:
# skip nonexistent file
self.entries = set()
return
self.entries = set(decodedir(fp.read()).splitlines())
if '' in self.entries:
fp.seek(0)
for n, line in enumerate(util.iterfile(fp)):
if not line.rstrip('\n'):
t = _('invalid entry in fncache, line %d') % (n + 1)
raise error.Abort(t)
fp.close()
def write(self, tr):
if self._dirty:
tr.addbackup('fncache')
fp = self.vfs('fncache', mode='wb', atomictemp=True)
if self.entries:
fp.write(encodedir('\n'.join(self.entries) + '\n'))
fp.close()
self._dirty = False
def add(self, fn):
if self.entries is None:
self._load()
if fn not in self.entries:
self._dirty = True
self.entries.add(fn)
def remove(self, fn):
if self.entries is None:
self._load()
try:
self.entries.remove(fn)
self._dirty = True
except KeyError:
pass
def __contains__(self, fn):
if self.entries is None:
self._load()
return fn in self.entries
def __iter__(self):
if self.entries is None:
self._load()
return iter(self.entries)
class _fncachevfs(scmutil.abstractvfs, scmutil.auditvfs):
def __init__(self, vfs, fnc, encode):
scmutil.auditvfs.__init__(self, vfs)
self.fncache = fnc
self.encode = encode
def __call__(self, path, mode='r', *args, **kw):
if mode not in ('r', 'rb') and (path.startswith('data/') or
path.startswith('meta/')):
self.fncache.add(path)
return self.vfs(self.encode(path), mode, *args, **kw)
def join(self, path):
if path:
return self.vfs.join(self.encode(path))
else:
return self.vfs.join(path)
class fncachestore(basicstore):
def __init__(self, path, vfstype, dotencode):
if dotencode:
encode = _pathencode
else:
encode = _plainhybridencode
self.encode = encode
vfs = vfstype(path + '/store')
self.path = vfs.base
self.pathsep = self.path + '/'
self.createmode = _calcmode(vfs)
vfs.createmode = self.createmode
self.rawvfs = vfs
fnc = fncache(vfs)
self.fncache = fnc
self.vfs = _fncachevfs(vfs, fnc, encode)
self.opener = self.vfs
def join(self, f):
return self.pathsep + self.encode(f)
def getsize(self, path):
return self.rawvfs.stat(path).st_size
def datafiles(self):
for f in sorted(self.fncache):
ef = self.encode(f)
try:
yield f, ef, self.getsize(ef)
except OSError as err:
if err.errno != errno.ENOENT:
raise
def copylist(self):
d = ('data meta dh fncache phaseroots obsstore'
' 00manifest.d 00manifest.i 00changelog.d 00changelog.i')
return (['requires', '00changelog.i'] +
['store/' + f for f in d.split()])
def write(self, tr):
self.fncache.write(tr)
def invalidatecaches(self):
self.fncache.entries = None
def markremoved(self, fn):
self.fncache.remove(fn)
def _exists(self, f):
ef = self.encode(f)
try:
self.getsize(ef)
return True
except OSError as err:
if err.errno != errno.ENOENT:
raise
# nonexistent entry
return False
def __contains__(self, path):
'''Checks if the store contains path'''
path = "/".join(("data", path))
# check for files (exact match)
e = path + '.i'
if e in self.fncache and self._exists(e):
return True
# now check for directories (prefix match)
if not path.endswith('/'):
path += '/'
for e in self.fncache:
if e.startswith(path) and self._exists(e):
return True
return False
def store(requirements, path, vfstype):
if 'store' in requirements:
if 'fncache' in requirements:
return fncachestore(path, vfstype, 'dotencode' in requirements)
return encodedstore(path, vfstype)
return basicstore(path, vfstype)