Mercurial > hg-stable
view mercurial/windows.py @ 18040:fe8caf28d580
strip: make query to get new bookmark target cheaper
The current query to get the new bookmark target for stripped revisions
involves multiple walks up the DAG, and is really expensive, taking over 2.5
seconds on a repository with over 400,000 changesets even if just one
changeset is being stripped.
A slightly simplified version of the current query is
max(heads(::<tostrip> - <tostrip>))
We make two observations here.
1. For any set s, max(heads(s)) == max(s). That is because revision numbers
define a topological order, so that the element with the highest revision
number in s will not have any children in s.
2. For any set s, max(::s - s) == max(parents(s) - s). In other words, the
ancestor of s with the highest revision number not in s is a parent of one
of the revs in s. Why? Because if it were an ancestor but not a parent of s,
it would have a descendant that would be a parent of s. This descendant
would have a higher revision number, leading to a contradiction.
Combining these two observations, we rewrite the revset query as
max(parents(<tostrip>) - <tostrip>)
The time complexity is now linear in the number of changesets being stripped.
For the above repository, the query now takes 0.1 seconds when one changeset
is stripped. This speeds up operations that use repair.strip, like the rebase
and strip commands.
author | Siddharth Agarwal <sid0@fb.com> |
---|---|
date | Wed, 05 Dec 2012 14:33:15 -0800 |
parents | 74912fe3d718 |
children | f0cfa27c712a |
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# windows.py - Windows utility function implementations for Mercurial # # Copyright 2005-2009 Matt Mackall <mpm@selenic.com> and others # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from i18n import _ import osutil, encoding import errno, msvcrt, os, re, stat, sys, _winreg import win32 executablepath = win32.executablepath getuser = win32.getuser hidewindow = win32.hidewindow makedir = win32.makedir nlinks = win32.nlinks oslink = win32.oslink samedevice = win32.samedevice samefile = win32.samefile setsignalhandler = win32.setsignalhandler spawndetached = win32.spawndetached split = os.path.split termwidth = win32.termwidth testpid = win32.testpid unlink = win32.unlink umask = 0022 # wrap osutil.posixfile to provide friendlier exceptions def posixfile(name, mode='r', buffering=-1): try: return osutil.posixfile(name, mode, buffering) except WindowsError, err: raise IOError(err.errno, '%s: %s' % (name, err.strerror)) posixfile.__doc__ = osutil.posixfile.__doc__ class winstdout(object): '''stdout on windows misbehaves if sent through a pipe''' def __init__(self, fp): self.fp = fp def __getattr__(self, key): return getattr(self.fp, key) def close(self): try: self.fp.close() except IOError: pass def write(self, s): try: # This is workaround for "Not enough space" error on # writing large size of data to console. limit = 16000 l = len(s) start = 0 self.softspace = 0 while start < l: end = start + limit self.fp.write(s[start:end]) start = end except IOError, inst: if inst.errno != 0: raise self.close() raise IOError(errno.EPIPE, 'Broken pipe') def flush(self): try: return self.fp.flush() except IOError, inst: if inst.errno != errno.EINVAL: raise self.close() raise IOError(errno.EPIPE, 'Broken pipe') sys.__stdout__ = sys.stdout = winstdout(sys.stdout) def _is_win_9x(): '''return true if run on windows 95, 98 or me.''' try: return sys.getwindowsversion()[3] == 1 except AttributeError: return 'command' in os.environ.get('comspec', '') def openhardlinks(): return not _is_win_9x() def parsepatchoutput(output_line): """parses the output produced by patch and returns the filename""" pf = output_line[14:] if pf[0] == '`': pf = pf[1:-1] # Remove the quotes return pf def sshargs(sshcmd, host, user, port): '''Build argument list for ssh or Plink''' pflag = 'plink' in sshcmd.lower() and '-P' or '-p' args = user and ("%s@%s" % (user, host)) or host return port and ("%s %s %s" % (args, pflag, port)) or args def setflags(f, l, x): pass def copymode(src, dst, mode=None): pass def checkexec(path): return False def checklink(path): return False def setbinary(fd): # When run without console, pipes may expose invalid # fileno(), usually set to -1. fno = getattr(fd, 'fileno', None) if fno is not None and fno() >= 0: msvcrt.setmode(fno(), os.O_BINARY) def pconvert(path): return path.replace(os.sep, '/') def localpath(path): return path.replace('/', '\\') def normpath(path): return pconvert(os.path.normpath(path)) def normcase(path): return encoding.upper(path) def realpath(path): ''' Returns the true, canonical file system path equivalent to the given path. ''' # TODO: There may be a more clever way to do this that also handles other, # less common file systems. return os.path.normpath(normcase(os.path.realpath(path))) def samestat(s1, s2): return False # A sequence of backslashes is special iff it precedes a double quote: # - if there's an even number of backslashes, the double quote is not # quoted (i.e. it ends the quoted region) # - if there's an odd number of backslashes, the double quote is quoted # - in both cases, every pair of backslashes is unquoted into a single # backslash # (See http://msdn2.microsoft.com/en-us/library/a1y7w461.aspx ) # So, to quote a string, we must surround it in double quotes, double # the number of backslashes that precede double quotes and add another # backslash before every double quote (being careful with the double # quote we've appended to the end) _quotere = None def shellquote(s): global _quotere if _quotere is None: _quotere = re.compile(r'(\\*)("|\\$)') return '"%s"' % _quotere.sub(r'\1\1\\\2', s) def quotecommand(cmd): """Build a command string suitable for os.popen* calls.""" if sys.version_info < (2, 7, 1): # Python versions since 2.7.1 do this extra quoting themselves return '"' + cmd + '"' return cmd def popen(command, mode='r'): # Work around "popen spawned process may not write to stdout # under windows" # http://bugs.python.org/issue1366 command += " 2> %s" % os.devnull return os.popen(quotecommand(command), mode) def explainexit(code): return _("exited with status %d") % code, code # if you change this stub into a real check, please try to implement the # username and groupname functions above, too. def isowner(st): return True def findexe(command): '''Find executable for command searching like cmd.exe does. If command is a basename then PATH is searched for command. PATH isn't searched if command is an absolute or relative path. An extension from PATHEXT is found and added if not present. If command isn't found None is returned.''' pathext = os.environ.get('PATHEXT', '.COM;.EXE;.BAT;.CMD') pathexts = [ext for ext in pathext.lower().split(os.pathsep)] if os.path.splitext(command)[1].lower() in pathexts: pathexts = [''] def findexisting(pathcommand): 'Will append extension (if needed) and return existing file' for ext in pathexts: executable = pathcommand + ext if os.path.exists(executable): return executable return None if os.sep in command: return findexisting(command) for path in os.environ.get('PATH', '').split(os.pathsep): executable = findexisting(os.path.join(path, command)) if executable is not None: return executable return findexisting(os.path.expanduser(os.path.expandvars(command))) _wantedkinds = set([stat.S_IFREG, stat.S_IFLNK]) def statfiles(files): '''Stat each file in files. Yield each stat, or None if a file does not exist or has a type we don't care about. Cluster and cache stat per directory to minimize number of OS stat calls.''' dircache = {} # dirname -> filename -> status | None if file does not exist getkind = stat.S_IFMT for nf in files: nf = normcase(nf) dir, base = os.path.split(nf) if not dir: dir = '.' cache = dircache.get(dir, None) if cache is None: try: dmap = dict([(normcase(n), s) for n, k, s in osutil.listdir(dir, True) if getkind(s) in _wantedkinds]) except OSError, err: # handle directory not found in Python version prior to 2.5 # Python <= 2.4 returns native Windows code 3 in errno # Python >= 2.5 returns ENOENT and adds winerror field # EINVAL is raised if dir is not a directory. if err.errno not in (3, errno.ENOENT, errno.EINVAL, errno.ENOTDIR): raise dmap = {} cache = dircache.setdefault(dir, dmap) yield cache.get(base, None) def username(uid=None): """Return the name of the user with the given uid. If uid is None, return the name of the current user.""" return None def groupname(gid=None): """Return the name of the group with the given gid. If gid is None, return the name of the current group.""" return None def _removedirs(name): """special version of os.removedirs that does not remove symlinked directories or junction points if they actually contain files""" if osutil.listdir(name): return os.rmdir(name) head, tail = os.path.split(name) if not tail: head, tail = os.path.split(head) while head and tail: try: if osutil.listdir(head): return os.rmdir(head) except (ValueError, OSError): break head, tail = os.path.split(head) def unlinkpath(f): """unlink and remove the directory if it is empty""" unlink(f) # try removing directories that might now be empty try: _removedirs(os.path.dirname(f)) except OSError: pass def rename(src, dst): '''atomically rename file src to dst, replacing dst if it exists''' try: os.rename(src, dst) except OSError, e: if e.errno != errno.EEXIST: raise unlink(dst) os.rename(src, dst) def gethgcmd(): return [sys.executable] + sys.argv[:1] def groupmembers(name): # Don't support groups on Windows for now raise KeyError def isexec(f): return False class cachestat(object): def __init__(self, path): pass def cacheable(self): return False def lookupreg(key, valname=None, scope=None): ''' Look up a key/value name in the Windows registry. valname: value name. If unspecified, the default value for the key is used. scope: optionally specify scope for registry lookup, this can be a sequence of scopes to look up in order. Default (CURRENT_USER, LOCAL_MACHINE). ''' if scope is None: scope = (_winreg.HKEY_CURRENT_USER, _winreg.HKEY_LOCAL_MACHINE) elif not isinstance(scope, (list, tuple)): scope = (scope,) for s in scope: try: val = _winreg.QueryValueEx(_winreg.OpenKey(s, key), valname)[0] # never let a Unicode string escape into the wild return encoding.tolocal(val.encode('UTF-8')) except EnvironmentError: pass expandglobs = True