revlog: remove some knowledge of sentinel nullid in index
I think the "-2" to mean "last position in index, not counting the
null revision at the end" is an implementation detail of the index
that we should avoid spreading knowledge of. I hope we can even remove
support for index[-2].
Differential Revision: https://phab.mercurial-scm.org/D4016
# posix.py - Posix 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 __future__ import absolute_import
import errno
import fcntl
import getpass
import grp
import os
import pwd
import re
import select
import stat
import sys
import tempfile
import unicodedata
from .i18n import _
from . import (
encoding,
error,
policy,
pycompat,
)
osutil = policy.importmod(r'osutil')
posixfile = open
normpath = os.path.normpath
samestat = os.path.samestat
try:
oslink = os.link
except AttributeError:
# Some platforms build Python without os.link on systems that are
# vaguely unix-like but don't have hardlink support. For those
# poor souls, just say we tried and that it failed so we fall back
# to copies.
def oslink(src, dst):
raise OSError(errno.EINVAL,
'hardlinks not supported: %s to %s' % (src, dst))
unlink = os.unlink
rename = os.rename
removedirs = os.removedirs
expandglobs = False
umask = os.umask(0)
os.umask(umask)
def split(p):
'''Same as posixpath.split, but faster
>>> import posixpath
>>> for f in [b'/absolute/path/to/file',
... b'relative/path/to/file',
... b'file_alone',
... b'path/to/directory/',
... b'/multiple/path//separators',
... b'/file_at_root',
... b'///multiple_leading_separators_at_root',
... b'']:
... assert split(f) == posixpath.split(f), f
'''
ht = p.rsplit('/', 1)
if len(ht) == 1:
return '', p
nh = ht[0].rstrip('/')
if nh:
return nh, ht[1]
return ht[0] + '/', ht[1]
def openhardlinks():
'''return true if it is safe to hold open file handles to hardlinks'''
return True
def nlinks(name):
'''return number of hardlinks for the given file'''
return os.lstat(name).st_nlink
def parsepatchoutput(output_line):
"""parses the output produced by patch and returns the filename"""
pf = output_line[14:]
if pycompat.sysplatform == 'OpenVMS':
if pf[0] == '`':
pf = pf[1:-1] # Remove the quotes
else:
if pf.startswith("'") and pf.endswith("'") and " " in pf:
pf = pf[1:-1] # Remove the quotes
return pf
def sshargs(sshcmd, host, user, port):
'''Build argument list for ssh'''
args = user and ("%s@%s" % (user, host)) or host
if '-' in args[:1]:
raise error.Abort(
_('illegal ssh hostname or username starting with -: %s') % args)
args = shellquote(args)
if port:
args = '-p %s %s' % (shellquote(port), args)
return args
def isexec(f):
"""check whether a file is executable"""
return (os.lstat(f).st_mode & 0o100 != 0)
def setflags(f, l, x):
st = os.lstat(f)
s = st.st_mode
if l:
if not stat.S_ISLNK(s):
# switch file to link
fp = open(f, 'rb')
data = fp.read()
fp.close()
unlink(f)
try:
os.symlink(data, f)
except OSError:
# failed to make a link, rewrite file
fp = open(f, "wb")
fp.write(data)
fp.close()
# no chmod needed at this point
return
if stat.S_ISLNK(s):
# switch link to file
data = os.readlink(f)
unlink(f)
fp = open(f, "wb")
fp.write(data)
fp.close()
s = 0o666 & ~umask # avoid restatting for chmod
sx = s & 0o100
if st.st_nlink > 1 and bool(x) != bool(sx):
# the file is a hardlink, break it
with open(f, "rb") as fp:
data = fp.read()
unlink(f)
with open(f, "wb") as fp:
fp.write(data)
if x and not sx:
# Turn on +x for every +r bit when making a file executable
# and obey umask.
os.chmod(f, s | (s & 0o444) >> 2 & ~umask)
elif not x and sx:
# Turn off all +x bits
os.chmod(f, s & 0o666)
def copymode(src, dst, mode=None):
'''Copy the file mode from the file at path src to dst.
If src doesn't exist, we're using mode instead. If mode is None, we're
using umask.'''
try:
st_mode = os.lstat(src).st_mode & 0o777
except OSError as inst:
if inst.errno != errno.ENOENT:
raise
st_mode = mode
if st_mode is None:
st_mode = ~umask
st_mode &= 0o666
os.chmod(dst, st_mode)
def checkexec(path):
"""
Check whether the given path is on a filesystem with UNIX-like exec flags
Requires a directory (like /foo/.hg)
"""
# VFAT on some Linux versions can flip mode but it doesn't persist
# a FS remount. Frequently we can detect it if files are created
# with exec bit on.
try:
EXECFLAGS = stat.S_IXUSR | stat.S_IXGRP | stat.S_IXOTH
cachedir = os.path.join(path, '.hg', 'cache')
if os.path.isdir(cachedir):
checkisexec = os.path.join(cachedir, 'checkisexec')
checknoexec = os.path.join(cachedir, 'checknoexec')
try:
m = os.stat(checkisexec).st_mode
except OSError as e:
if e.errno != errno.ENOENT:
raise
# checkisexec does not exist - fall through ...
else:
# checkisexec exists, check if it actually is exec
if m & EXECFLAGS != 0:
# ensure checkisexec exists, check it isn't exec
try:
m = os.stat(checknoexec).st_mode
except OSError as e:
if e.errno != errno.ENOENT:
raise
open(checknoexec, 'w').close() # might fail
m = os.stat(checknoexec).st_mode
if m & EXECFLAGS == 0:
# check-exec is exec and check-no-exec is not exec
return True
# checknoexec exists but is exec - delete it
unlink(checknoexec)
# checkisexec exists but is not exec - delete it
unlink(checkisexec)
# check using one file, leave it as checkisexec
checkdir = cachedir
else:
# check directly in path and don't leave checkisexec behind
checkdir = path
checkisexec = None
fh, fn = pycompat.mkstemp(dir=checkdir, prefix='hg-checkexec-')
try:
os.close(fh)
m = os.stat(fn).st_mode
if m & EXECFLAGS == 0:
os.chmod(fn, m & 0o777 | EXECFLAGS)
if os.stat(fn).st_mode & EXECFLAGS != 0:
if checkisexec is not None:
os.rename(fn, checkisexec)
fn = None
return True
finally:
if fn is not None:
unlink(fn)
except (IOError, OSError):
# we don't care, the user probably won't be able to commit anyway
return False
def checklink(path):
"""check whether the given path is on a symlink-capable filesystem"""
# mktemp is not racy because symlink creation will fail if the
# file already exists
while True:
cachedir = os.path.join(path, '.hg', 'cache')
checklink = os.path.join(cachedir, 'checklink')
# try fast path, read only
if os.path.islink(checklink):
return True
if os.path.isdir(cachedir):
checkdir = cachedir
else:
checkdir = path
cachedir = None
name = tempfile.mktemp(dir=pycompat.fsdecode(checkdir),
prefix=r'checklink-')
name = pycompat.fsencode(name)
try:
fd = None
if cachedir is None:
fd = pycompat.namedtempfile(dir=checkdir,
prefix='hg-checklink-')
target = os.path.basename(fd.name)
else:
# create a fixed file to link to; doesn't matter if it
# already exists.
target = 'checklink-target'
try:
fullpath = os.path.join(cachedir, target)
open(fullpath, 'w').close()
except IOError as inst:
if inst[0] == errno.EACCES:
# If we can't write to cachedir, just pretend
# that the fs is readonly and by association
# that the fs won't support symlinks. This
# seems like the least dangerous way to avoid
# data loss.
return False
raise
try:
os.symlink(target, name)
if cachedir is None:
unlink(name)
else:
try:
os.rename(name, checklink)
except OSError:
unlink(name)
return True
except OSError as inst:
# link creation might race, try again
if inst.errno == errno.EEXIST:
continue
raise
finally:
if fd is not None:
fd.close()
except AttributeError:
return False
except OSError as inst:
# sshfs might report failure while successfully creating the link
if inst.errno == errno.EIO and os.path.exists(name):
unlink(name)
return False
def checkosfilename(path):
'''Check that the base-relative path is a valid filename on this platform.
Returns None if the path is ok, or a UI string describing the problem.'''
return None # on posix platforms, every path is ok
def getfsmountpoint(dirpath):
'''Get the filesystem mount point from a directory (best-effort)
Returns None if we are unsure. Raises OSError on ENOENT, EPERM, etc.
'''
return getattr(osutil, 'getfsmountpoint', lambda x: None)(dirpath)
def getfstype(dirpath):
'''Get the filesystem type name from a directory (best-effort)
Returns None if we are unsure. Raises OSError on ENOENT, EPERM, etc.
'''
return getattr(osutil, 'getfstype', lambda x: None)(dirpath)
def setbinary(fd):
pass
def pconvert(path):
return path
def localpath(path):
return path
def samefile(fpath1, fpath2):
"""Returns whether path1 and path2 refer to the same file. This is only
guaranteed to work for files, not directories."""
return os.path.samefile(fpath1, fpath2)
def samedevice(fpath1, fpath2):
"""Returns whether fpath1 and fpath2 are on the same device. This is only
guaranteed to work for files, not directories."""
st1 = os.lstat(fpath1)
st2 = os.lstat(fpath2)
return st1.st_dev == st2.st_dev
# os.path.normcase is a no-op, which doesn't help us on non-native filesystems
def normcase(path):
return path.lower()
# what normcase does to ASCII strings
normcasespec = encoding.normcasespecs.lower
# fallback normcase function for non-ASCII strings
normcasefallback = normcase
if pycompat.isdarwin:
def normcase(path):
'''
Normalize a filename for OS X-compatible comparison:
- escape-encode invalid characters
- decompose to NFD
- lowercase
- omit ignored characters [200c-200f, 202a-202e, 206a-206f,feff]
>>> normcase(b'UPPER')
'upper'
>>> normcase(b'Caf\\xc3\\xa9')
'cafe\\xcc\\x81'
>>> normcase(b'\\xc3\\x89')
'e\\xcc\\x81'
>>> normcase(b'\\xb8\\xca\\xc3\\xca\\xbe\\xc8.JPG') # issue3918
'%b8%ca%c3\\xca\\xbe%c8.jpg'
'''
try:
return encoding.asciilower(path) # exception for non-ASCII
except UnicodeDecodeError:
return normcasefallback(path)
normcasespec = encoding.normcasespecs.lower
def normcasefallback(path):
try:
u = path.decode('utf-8')
except UnicodeDecodeError:
# OS X percent-encodes any bytes that aren't valid utf-8
s = ''
pos = 0
l = len(path)
while pos < l:
try:
c = encoding.getutf8char(path, pos)
pos += len(c)
except ValueError:
c = '%%%02X' % ord(path[pos:pos + 1])
pos += 1
s += c
u = s.decode('utf-8')
# Decompose then lowercase (HFS+ technote specifies lower)
enc = unicodedata.normalize(r'NFD', u).lower().encode('utf-8')
# drop HFS+ ignored characters
return encoding.hfsignoreclean(enc)
if pycompat.sysplatform == 'cygwin':
# workaround for cygwin, in which mount point part of path is
# treated as case sensitive, even though underlying NTFS is case
# insensitive.
# default mount points
cygwinmountpoints = sorted([
"/usr/bin",
"/usr/lib",
"/cygdrive",
], reverse=True)
# use upper-ing as normcase as same as NTFS workaround
def normcase(path):
pathlen = len(path)
if (pathlen == 0) or (path[0] != pycompat.ossep):
# treat as relative
return encoding.upper(path)
# to preserve case of mountpoint part
for mp in cygwinmountpoints:
if not path.startswith(mp):
continue
mplen = len(mp)
if mplen == pathlen: # mount point itself
return mp
if path[mplen] == pycompat.ossep:
return mp + encoding.upper(path[mplen:])
return encoding.upper(path)
normcasespec = encoding.normcasespecs.other
normcasefallback = normcase
# Cygwin translates native ACLs to POSIX permissions,
# but these translations are not supported by native
# tools, so the exec bit tends to be set erroneously.
# Therefore, disable executable bit access on Cygwin.
def checkexec(path):
return False
# Similarly, Cygwin's symlink emulation is likely to create
# problems when Mercurial is used from both Cygwin and native
# Windows, with other native tools, or on shared volumes
def checklink(path):
return False
_needsshellquote = None
def shellquote(s):
if pycompat.sysplatform == 'OpenVMS':
return '"%s"' % s
global _needsshellquote
if _needsshellquote is None:
_needsshellquote = re.compile(br'[^a-zA-Z0-9._/+-]').search
if s and not _needsshellquote(s):
# "s" shouldn't have to be quoted
return s
else:
return "'%s'" % s.replace("'", "'\\''")
def shellsplit(s):
"""Parse a command string in POSIX shell way (best-effort)"""
return pycompat.shlexsplit(s, posix=True)
def quotecommand(cmd):
return cmd
def testpid(pid):
'''return False if pid dead, True if running or not sure'''
if pycompat.sysplatform == 'OpenVMS':
return True
try:
os.kill(pid, 0)
return True
except OSError as inst:
return inst.errno != errno.ESRCH
def isowner(st):
"""Return True if the stat object st is from the current user."""
return st.st_uid == os.getuid()
def findexe(command):
'''Find executable for command searching like which does.
If command is a basename then PATH is searched for command.
PATH isn't searched if command is an absolute or relative path.
If command isn't found None is returned.'''
if pycompat.sysplatform == 'OpenVMS':
return command
def findexisting(executable):
'Will return executable if existing file'
if os.path.isfile(executable) and os.access(executable, os.X_OK):
return executable
return None
if pycompat.ossep in command:
return findexisting(command)
if pycompat.sysplatform == 'plan9':
return findexisting(os.path.join('/bin', command))
for path in encoding.environ.get('PATH', '').split(pycompat.ospathsep):
executable = findexisting(os.path.join(path, command))
if executable is not None:
return executable
return None
def setsignalhandler():
pass
_wantedkinds = {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.'''
lstat = os.lstat
getkind = stat.S_IFMT
for nf in files:
try:
st = lstat(nf)
if getkind(st.st_mode) not in _wantedkinds:
st = None
except OSError as err:
if err.errno not in (errno.ENOENT, errno.ENOTDIR):
raise
st = None
yield st
def getuser():
'''return name of current user'''
return pycompat.fsencode(getpass.getuser())
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."""
if uid is None:
uid = os.getuid()
try:
return pycompat.fsencode(pwd.getpwuid(uid)[0])
except KeyError:
return b'%d' % uid
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."""
if gid is None:
gid = os.getgid()
try:
return grp.getgrgid(gid)[0]
except KeyError:
return str(gid)
def groupmembers(name):
"""Return the list of members of the group with the given
name, KeyError if the group does not exist.
"""
return list(grp.getgrnam(name).gr_mem)
def spawndetached(args):
return os.spawnvp(os.P_NOWAIT | getattr(os, 'P_DETACH', 0),
args[0], args)
def gethgcmd():
return sys.argv[:1]
def makedir(path, notindexed):
os.mkdir(path)
def lookupreg(key, name=None, scope=None):
return None
def hidewindow():
"""Hide current shell window.
Used to hide the window opened when starting asynchronous
child process under Windows, unneeded on other systems.
"""
pass
class cachestat(object):
def __init__(self, path):
self.stat = os.stat(path)
def cacheable(self):
return bool(self.stat.st_ino)
__hash__ = object.__hash__
def __eq__(self, other):
try:
# Only dev, ino, size, mtime and atime are likely to change. Out
# of these, we shouldn't compare atime but should compare the
# rest. However, one of the other fields changing indicates
# something fishy going on, so return False if anything but atime
# changes.
return (self.stat.st_mode == other.stat.st_mode and
self.stat.st_ino == other.stat.st_ino and
self.stat.st_dev == other.stat.st_dev and
self.stat.st_nlink == other.stat.st_nlink and
self.stat.st_uid == other.stat.st_uid and
self.stat.st_gid == other.stat.st_gid and
self.stat.st_size == other.stat.st_size and
self.stat[stat.ST_MTIME] == other.stat[stat.ST_MTIME] and
self.stat[stat.ST_CTIME] == other.stat[stat.ST_CTIME])
except AttributeError:
return False
def __ne__(self, other):
return not self == other
def statislink(st):
'''check whether a stat result is a symlink'''
return st and stat.S_ISLNK(st.st_mode)
def statisexec(st):
'''check whether a stat result is an executable file'''
return st and (st.st_mode & 0o100 != 0)
def poll(fds):
"""block until something happens on any file descriptor
This is a generic helper that will check for any activity
(read, write. exception) and return the list of touched files.
In unsupported cases, it will raise a NotImplementedError"""
try:
while True:
try:
res = select.select(fds, fds, fds)
break
except select.error as inst:
if inst.args[0] == errno.EINTR:
continue
raise
except ValueError: # out of range file descriptor
raise NotImplementedError()
return sorted(list(set(sum(res, []))))
def readpipe(pipe):
"""Read all available data from a pipe."""
# We can't fstat() a pipe because Linux will always report 0.
# So, we set the pipe to non-blocking mode and read everything
# that's available.
flags = fcntl.fcntl(pipe, fcntl.F_GETFL)
flags |= os.O_NONBLOCK
oldflags = fcntl.fcntl(pipe, fcntl.F_SETFL, flags)
try:
chunks = []
while True:
try:
s = pipe.read()
if not s:
break
chunks.append(s)
except IOError:
break
return ''.join(chunks)
finally:
fcntl.fcntl(pipe, fcntl.F_SETFL, oldflags)
def bindunixsocket(sock, path):
"""Bind the UNIX domain socket to the specified path"""
# use relative path instead of full path at bind() if possible, since
# AF_UNIX path has very small length limit (107 chars) on common
# platforms (see sys/un.h)
dirname, basename = os.path.split(path)
bakwdfd = None
if dirname:
bakwdfd = os.open('.', os.O_DIRECTORY)
os.chdir(dirname)
sock.bind(basename)
if bakwdfd:
os.fchdir(bakwdfd)
os.close(bakwdfd)