deltas: skip if projected delta size is bigger than previous snapshot
Before computing any delta, we get a basic estimation of the delta size we can
expect and the resulted compressed value. We then checks this projected size
against the `size(snapshotⁿ) > size(snapshotⁿ⁺¹)` constraint. This allows to
exclude potential base candidates before doing any expensive computation.
This only apply to the intermediate-snapshot case since this constraint only
apply to them.
For some pathological cases of a private repository this step provide a
significant performance boost (timing from `hg perfrevlogwrite`):
before: 14.115908 seconds
after: 3.145906 seconds
# pycompat.py - portability shim for python 3
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""Mercurial portability shim for python 3.
This contains aliases to hide python version-specific details from the core.
"""
from __future__ import absolute_import
import getopt
import inspect
import os
import shlex
import sys
import tempfile
ispy3 = (sys.version_info[0] >= 3)
ispypy = (r'__pypy__' in sys.builtin_module_names)
if not ispy3:
import cookielib
import cPickle as pickle
import httplib
import Queue as queue
import SocketServer as socketserver
import xmlrpclib
from .thirdparty.concurrent import futures
def future_set_exception_info(f, exc_info):
f.set_exception_info(*exc_info)
else:
import concurrent.futures as futures
import http.cookiejar as cookielib
import http.client as httplib
import pickle
import queue as queue
import socketserver
import xmlrpc.client as xmlrpclib
def future_set_exception_info(f, exc_info):
f.set_exception(exc_info[0])
def identity(a):
return a
def _rapply(f, xs):
if xs is None:
# assume None means non-value of optional data
return xs
if isinstance(xs, (list, set, tuple)):
return type(xs)(_rapply(f, x) for x in xs)
if isinstance(xs, dict):
return type(xs)((_rapply(f, k), _rapply(f, v)) for k, v in xs.items())
return f(xs)
def rapply(f, xs):
"""Apply function recursively to every item preserving the data structure
>>> def f(x):
... return 'f(%s)' % x
>>> rapply(f, None) is None
True
>>> rapply(f, 'a')
'f(a)'
>>> rapply(f, {'a'}) == {'f(a)'}
True
>>> rapply(f, ['a', 'b', None, {'c': 'd'}, []])
['f(a)', 'f(b)', None, {'f(c)': 'f(d)'}, []]
>>> xs = [object()]
>>> rapply(identity, xs) is xs
True
"""
if f is identity:
# fast path mainly for py2
return xs
return _rapply(f, xs)
if ispy3:
import builtins
import functools
import io
import struct
fsencode = os.fsencode
fsdecode = os.fsdecode
oscurdir = os.curdir.encode('ascii')
oslinesep = os.linesep.encode('ascii')
osname = os.name.encode('ascii')
ospathsep = os.pathsep.encode('ascii')
ospardir = os.pardir.encode('ascii')
ossep = os.sep.encode('ascii')
osaltsep = os.altsep
if osaltsep:
osaltsep = osaltsep.encode('ascii')
sysplatform = sys.platform.encode('ascii')
sysexecutable = sys.executable
if sysexecutable:
sysexecutable = os.fsencode(sysexecutable)
bytesio = io.BytesIO
# TODO deprecate stringio name, as it is a lie on Python 3.
stringio = bytesio
def maplist(*args):
return list(map(*args))
def rangelist(*args):
return list(range(*args))
def ziplist(*args):
return list(zip(*args))
rawinput = input
getargspec = inspect.getfullargspec
long = int
# TODO: .buffer might not exist if std streams were replaced; we'll need
# a silly wrapper to make a bytes stream backed by a unicode one.
stdin = sys.stdin.buffer
stdout = sys.stdout.buffer
stderr = sys.stderr.buffer
# Since Python 3 converts argv to wchar_t type by Py_DecodeLocale() on Unix,
# we can use os.fsencode() to get back bytes argv.
#
# https://hg.python.org/cpython/file/v3.5.1/Programs/python.c#l55
#
# TODO: On Windows, the native argv is wchar_t, so we'll need a different
# workaround to simulate the Python 2 (i.e. ANSI Win32 API) behavior.
if getattr(sys, 'argv', None) is not None:
sysargv = list(map(os.fsencode, sys.argv))
bytechr = struct.Struct(r'>B').pack
byterepr = b'%r'.__mod__
class bytestr(bytes):
"""A bytes which mostly acts as a Python 2 str
>>> bytestr(), bytestr(bytearray(b'foo')), bytestr(u'ascii'), bytestr(1)
('', 'foo', 'ascii', '1')
>>> s = bytestr(b'foo')
>>> assert s is bytestr(s)
__bytes__() should be called if provided:
>>> class bytesable(object):
... def __bytes__(self):
... return b'bytes'
>>> bytestr(bytesable())
'bytes'
There's no implicit conversion from non-ascii str as its encoding is
unknown:
>>> bytestr(chr(0x80)) # doctest: +ELLIPSIS
Traceback (most recent call last):
...
UnicodeEncodeError: ...
Comparison between bytestr and bytes should work:
>>> assert bytestr(b'foo') == b'foo'
>>> assert b'foo' == bytestr(b'foo')
>>> assert b'f' in bytestr(b'foo')
>>> assert bytestr(b'f') in b'foo'
Sliced elements should be bytes, not integer:
>>> s[1], s[:2]
(b'o', b'fo')
>>> list(s), list(reversed(s))
([b'f', b'o', b'o'], [b'o', b'o', b'f'])
As bytestr type isn't propagated across operations, you need to cast
bytes to bytestr explicitly:
>>> s = bytestr(b'foo').upper()
>>> t = bytestr(s)
>>> s[0], t[0]
(70, b'F')
Be careful to not pass a bytestr object to a function which expects
bytearray-like behavior.
>>> t = bytes(t) # cast to bytes
>>> assert type(t) is bytes
"""
def __new__(cls, s=b''):
if isinstance(s, bytestr):
return s
if (not isinstance(s, (bytes, bytearray))
and not hasattr(s, u'__bytes__')): # hasattr-py3-only
s = str(s).encode(u'ascii')
return bytes.__new__(cls, s)
def __getitem__(self, key):
s = bytes.__getitem__(self, key)
if not isinstance(s, bytes):
s = bytechr(s)
return s
def __iter__(self):
return iterbytestr(bytes.__iter__(self))
def __repr__(self):
return bytes.__repr__(self)[1:] # drop b''
def iterbytestr(s):
"""Iterate bytes as if it were a str object of Python 2"""
return map(bytechr, s)
def maybebytestr(s):
"""Promote bytes to bytestr"""
if isinstance(s, bytes):
return bytestr(s)
return s
def sysbytes(s):
"""Convert an internal str (e.g. keyword, __doc__) back to bytes
This never raises UnicodeEncodeError, but only ASCII characters
can be round-trip by sysstr(sysbytes(s)).
"""
return s.encode(u'utf-8')
def sysstr(s):
"""Return a keyword str to be passed to Python functions such as
getattr() and str.encode()
This never raises UnicodeDecodeError. Non-ascii characters are
considered invalid and mapped to arbitrary but unique code points
such that 'sysstr(a) != sysstr(b)' for all 'a != b'.
"""
if isinstance(s, builtins.str):
return s
return s.decode(u'latin-1')
def strurl(url):
"""Converts a bytes url back to str"""
if isinstance(url, bytes):
return url.decode(u'ascii')
return url
def bytesurl(url):
"""Converts a str url to bytes by encoding in ascii"""
if isinstance(url, str):
return url.encode(u'ascii')
return url
def raisewithtb(exc, tb):
"""Raise exception with the given traceback"""
raise exc.with_traceback(tb)
def getdoc(obj):
"""Get docstring as bytes; may be None so gettext() won't confuse it
with _('')"""
doc = getattr(obj, u'__doc__', None)
if doc is None:
return doc
return sysbytes(doc)
def _wrapattrfunc(f):
@functools.wraps(f)
def w(object, name, *args):
return f(object, sysstr(name), *args)
return w
# these wrappers are automagically imported by hgloader
delattr = _wrapattrfunc(builtins.delattr)
getattr = _wrapattrfunc(builtins.getattr)
hasattr = _wrapattrfunc(builtins.hasattr)
setattr = _wrapattrfunc(builtins.setattr)
xrange = builtins.range
unicode = str
def open(name, mode=b'r', buffering=-1, encoding=None):
return builtins.open(name, sysstr(mode), buffering, encoding)
safehasattr = _wrapattrfunc(builtins.hasattr)
def _getoptbwrapper(orig, args, shortlist, namelist):
"""
Takes bytes arguments, converts them to unicode, pass them to
getopt.getopt(), convert the returned values back to bytes and then
return them for Python 3 compatibility as getopt.getopt() don't accepts
bytes on Python 3.
"""
args = [a.decode('latin-1') for a in args]
shortlist = shortlist.decode('latin-1')
namelist = [a.decode('latin-1') for a in namelist]
opts, args = orig(args, shortlist, namelist)
opts = [(a[0].encode('latin-1'), a[1].encode('latin-1'))
for a in opts]
args = [a.encode('latin-1') for a in args]
return opts, args
def strkwargs(dic):
"""
Converts the keys of a python dictonary to str i.e. unicodes so that
they can be passed as keyword arguments as dictonaries with bytes keys
can't be passed as keyword arguments to functions on Python 3.
"""
dic = dict((k.decode('latin-1'), v) for k, v in dic.iteritems())
return dic
def byteskwargs(dic):
"""
Converts keys of python dictonaries to bytes as they were converted to
str to pass that dictonary as a keyword argument on Python 3.
"""
dic = dict((k.encode('latin-1'), v) for k, v in dic.iteritems())
return dic
# TODO: handle shlex.shlex().
def shlexsplit(s, comments=False, posix=True):
"""
Takes bytes argument, convert it to str i.e. unicodes, pass that into
shlex.split(), convert the returned value to bytes and return that for
Python 3 compatibility as shelx.split() don't accept bytes on Python 3.
"""
ret = shlex.split(s.decode('latin-1'), comments, posix)
return [a.encode('latin-1') for a in ret]
else:
import cStringIO
xrange = xrange
unicode = unicode
bytechr = chr
byterepr = repr
bytestr = str
iterbytestr = iter
maybebytestr = identity
sysbytes = identity
sysstr = identity
strurl = identity
bytesurl = identity
# this can't be parsed on Python 3
exec('def raisewithtb(exc, tb):\n'
' raise exc, None, tb\n')
def fsencode(filename):
"""
Partial backport from os.py in Python 3, which only accepts bytes.
In Python 2, our paths should only ever be bytes, a unicode path
indicates a bug.
"""
if isinstance(filename, str):
return filename
else:
raise TypeError(
r"expect str, not %s" % type(filename).__name__)
# In Python 2, fsdecode() has a very chance to receive bytes. So it's
# better not to touch Python 2 part as it's already working fine.
fsdecode = identity
def getdoc(obj):
return getattr(obj, '__doc__', None)
_notset = object()
def safehasattr(thing, attr):
return getattr(thing, attr, _notset) is not _notset
def _getoptbwrapper(orig, args, shortlist, namelist):
return orig(args, shortlist, namelist)
strkwargs = identity
byteskwargs = identity
oscurdir = os.curdir
oslinesep = os.linesep
osname = os.name
ospathsep = os.pathsep
ospardir = os.pardir
ossep = os.sep
osaltsep = os.altsep
long = long
stdin = sys.stdin
stdout = sys.stdout
stderr = sys.stderr
if getattr(sys, 'argv', None) is not None:
sysargv = sys.argv
sysplatform = sys.platform
sysexecutable = sys.executable
shlexsplit = shlex.split
bytesio = cStringIO.StringIO
stringio = bytesio
maplist = map
rangelist = range
ziplist = zip
rawinput = raw_input
getargspec = inspect.getargspec
isjython = sysplatform.startswith(b'java')
isdarwin = sysplatform.startswith(b'darwin')
islinux = sysplatform.startswith(b'linux')
isposix = osname == b'posix'
iswindows = osname == b'nt'
def getoptb(args, shortlist, namelist):
return _getoptbwrapper(getopt.getopt, args, shortlist, namelist)
def gnugetoptb(args, shortlist, namelist):
return _getoptbwrapper(getopt.gnu_getopt, args, shortlist, namelist)
def mkdtemp(suffix=b'', prefix=b'tmp', dir=None):
return tempfile.mkdtemp(suffix, prefix, dir)
# text=True is not supported; use util.from/tonativeeol() instead
def mkstemp(suffix=b'', prefix=b'tmp', dir=None):
return tempfile.mkstemp(suffix, prefix, dir)
# mode must include 'b'ytes as encoding= is not supported
def namedtempfile(mode=b'w+b', bufsize=-1, suffix=b'', prefix=b'tmp', dir=None,
delete=True):
mode = sysstr(mode)
assert r'b' in mode
return tempfile.NamedTemporaryFile(mode, bufsize, suffix=suffix,
prefix=prefix, dir=dir, delete=delete)