Mercurial > hg
view mercurial/pycompat.py @ 32151:4d504e541d3d
rebase: use matcher to optimize manifestmerge
The old merge code would call manifestmerge and calculate the complete diff
between the source to the destination. In many cases, like rebase, the vast
majority of differences between the source and destination are irrelevant
because they are differences between the destination and the common ancestor
only, and therefore don't affect the merge. Since most actions are 'keep', all
the effort to compute them is wasted.
Instead, let's compute the difference between the source and the common ancestor
and only perform the diff of those files against the merge destination. When
using treemanifest, this lets us avoid loading almost the entire tree when
rebasing from a very old ancestor. This speeds up rebase of an old stack of 27
commits by 20x.
In mozilla-central, without treemanifest, when rebasing a commit from
default~100000 to default, this speeds up the manifestmerge step from 2.6s to
1.2s. However, the additional diff adds an overhead to all manifestmerge calls,
especially for flat manifests. When rebasing a commit from default~1 to default
it appears to add 100ms in mozilla-central. While we could put this optimization
behind a flag, I think the fact that it makes merge O(number of changes being
applied) instead of O(number of changes between X and Y) justifies it.
author | Durham Goode <durham@fb.com> |
---|---|
date | Wed, 03 May 2017 10:43:59 -0700 |
parents | bc0579a25f82 |
children | 76f9a0009b4b |
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# 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 os import shlex import sys ispy3 = (sys.version_info[0] >= 3) if not ispy3: import cookielib import cPickle as pickle import httplib import Queue as _queue import SocketServer as socketserver import xmlrpclib else: import http.cookiejar as cookielib import http.client as httplib import pickle import queue as _queue import socketserver import xmlrpc.client as xmlrpclib def identity(a): return a if ispy3: import builtins import functools import io import struct fsencode = os.fsencode fsdecode = os.fsdecode # A bytes version of os.name. oslinesep = os.linesep.encode('ascii') osname = os.name.encode('ascii') ospathsep = os.pathsep.encode('ascii') ossep = os.sep.encode('ascii') osaltsep = os.altsep if osaltsep: osaltsep = osaltsep.encode('ascii') # os.getcwd() on Python 3 returns string, but it has os.getcwdb() which # returns bytes. getcwd = os.getcwdb sysplatform = sys.platform.encode('ascii') sysexecutable = sys.executable if sysexecutable: sysexecutable = os.fsencode(sysexecutable) stringio = io.BytesIO maplist = lambda *args: list(map(*args)) # 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('>B').pack class bytestr(bytes): """A bytes which mostly acts as a Python 2 str >>> bytestr(), bytestr(bytearray(b'foo')), bytestr(u'ascii'), bytestr(1) (b'', b'foo', b'ascii', b'1') >>> s = bytestr(b'foo') >>> assert s is bytestr(s) 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)): 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 iterbytestr(s): """Iterate bytes as if it were a str object of Python 2""" return map(bytechr, 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 _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='r', buffering=-1): return builtins.open(name, sysstr(mode), buffering) # getopt.getopt() on Python 3 deals with unicodes internally so we cannot # pass bytes there. Passing unicodes will result in unicodes as return # values which we need to convert again to bytes. def getoptb(args, shortlist, namelist): 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 = getopt.getopt(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 # keys of keyword arguments in Python need to be strings which are unicodes # Python 3. This function takes keyword arguments, convert the keys to str. def strkwargs(dic): dic = dict((k.decode('latin-1'), v) for k, v in dic.iteritems()) return dic # keys of keyword arguments need to be unicode while passing into # a function. This function helps us to convert those keys back to bytes # again as we need to deal with bytes. def byteskwargs(dic): dic = dict((k.encode('latin-1'), v) for k, v in dic.iteritems()) return dic # shlex.split() accepts unicodes on Python 3. This function takes bytes # argument, convert it into unicodes, pass into shlex.split(), convert the # returned value to bytes and return that. # TODO: handle shlex.shlex(). def shlexsplit(s): ret = shlex.split(s.decode('latin-1')) return [a.encode('latin-1') for a in ret] else: import cStringIO bytechr = chr bytestr = str iterbytestr = iter sysbytes = identity sysstr = identity # 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. def fsencode(filename): if isinstance(filename, str): return filename else: raise TypeError( "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 getoptb(args, shortlist, namelist): return getopt.getopt(args, shortlist, namelist) strkwargs = identity byteskwargs = identity oslinesep = os.linesep osname = os.name ospathsep = os.pathsep ossep = os.sep osaltsep = os.altsep stdin = sys.stdin stdout = sys.stdout stderr = sys.stderr if getattr(sys, 'argv', None) is not None: sysargv = sys.argv sysplatform = sys.platform getcwd = os.getcwd sysexecutable = sys.executable shlexsplit = shlex.split stringio = cStringIO.StringIO maplist = map empty = _queue.Empty queue = _queue.Queue class _pycompatstub(object): def __init__(self): self._aliases = {} def _registeraliases(self, origin, items): """Add items that will be populated at the first access""" items = map(sysstr, items) self._aliases.update( (item.replace(sysstr('_'), sysstr('')).lower(), (origin, item)) for item in items) def _registeralias(self, origin, attr, name): """Alias ``origin``.``attr`` as ``name``""" self._aliases[sysstr(name)] = (origin, sysstr(attr)) def __getattr__(self, name): try: origin, item = self._aliases[name] except KeyError: raise AttributeError(name) self.__dict__[name] = obj = getattr(origin, item) return obj httpserver = _pycompatstub() urlreq = _pycompatstub() urlerr = _pycompatstub() if not ispy3: import BaseHTTPServer import CGIHTTPServer import SimpleHTTPServer import urllib2 import urllib import urlparse urlreq._registeraliases(urllib, ( "addclosehook", "addinfourl", "ftpwrapper", "pathname2url", "quote", "splitattr", "splitpasswd", "splitport", "splituser", "unquote", "url2pathname", "urlencode", )) urlreq._registeraliases(urllib2, ( "AbstractHTTPHandler", "BaseHandler", "build_opener", "FileHandler", "FTPHandler", "HTTPBasicAuthHandler", "HTTPDigestAuthHandler", "HTTPHandler", "HTTPPasswordMgrWithDefaultRealm", "HTTPSHandler", "install_opener", "ProxyHandler", "Request", "urlopen", )) urlreq._registeraliases(urlparse, ( "urlparse", "urlunparse", )) urlerr._registeraliases(urllib2, ( "HTTPError", "URLError", )) httpserver._registeraliases(BaseHTTPServer, ( "HTTPServer", "BaseHTTPRequestHandler", )) httpserver._registeraliases(SimpleHTTPServer, ( "SimpleHTTPRequestHandler", )) httpserver._registeraliases(CGIHTTPServer, ( "CGIHTTPRequestHandler", )) else: import urllib.parse urlreq._registeraliases(urllib.parse, ( "splitattr", "splitpasswd", "splitport", "splituser", "urlparse", "urlunparse", )) urlreq._registeralias(urllib.parse, "unquote_to_bytes", "unquote") import urllib.request urlreq._registeraliases(urllib.request, ( "AbstractHTTPHandler", "BaseHandler", "build_opener", "FileHandler", "FTPHandler", "ftpwrapper", "HTTPHandler", "HTTPSHandler", "install_opener", "pathname2url", "HTTPBasicAuthHandler", "HTTPDigestAuthHandler", "HTTPPasswordMgrWithDefaultRealm", "ProxyHandler", "Request", "url2pathname", "urlopen", )) import urllib.response urlreq._registeraliases(urllib.response, ( "addclosehook", "addinfourl", )) import urllib.error urlerr._registeraliases(urllib.error, ( "HTTPError", "URLError", )) import http.server httpserver._registeraliases(http.server, ( "HTTPServer", "BaseHTTPRequestHandler", "SimpleHTTPRequestHandler", "CGIHTTPRequestHandler", )) # urllib.parse.quote() accepts both str and bytes, decodes bytes # (if necessary), and returns str. This is wonky. We provide a custom # implementation that only accepts bytes and emits bytes. def quote(s, safe=r'/'): s = urllib.parse.quote_from_bytes(s, safe=safe) return s.encode('ascii', 'strict') # urllib.parse.urlencode() returns str. We use this function to make # sure we return bytes. def urlencode(query, doseq=False): s = urllib.parse.urlencode(query, doseq=doseq) return s.encode('ascii') urlreq.quote = quote urlreq.urlencode = urlencode