mercurial/windows.py

posix, windows: introduce cachestat

This class contains a stat result, and possibly other file info to reliably
determine between two points in time whether a file has changed.

Uniquely identifying a file gives us that reliability because we either
atomic rename or append. So one of two will happen: the file 'id' will change,
or the size of the file will change.

posix implements it simply by calling os.stat() and checking if the result
has st_ino.

For now on Windows we always assume the path is uncacheable. This can be
improved on NTFS due to file IDs: http://msdn.microsoft.com/en-us/library/aa363788(v=vs.85).aspx

So we need to find out if a file path is on an NTFS drive, for that we have:

- GetVolumeInformation, which unfortunately only works with a root path (but is available on XP)
- GetVolumeInformationByHandleW, works on a full file path but requires Vista or higher

# windows.py - Windows utility function implementations for Mercurial
#
#  Copyright 2005-2009 Matt Mackall <[e-mail]> 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
import errno, msvcrt, os, re, sys

nulldev = 'NUL:'
umask = 002

# 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 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.
    if hasattr(fd, 'fileno') and fd.fileno() >= 0:
        msvcrt.setmode(fd.fileno(), os.O_BINARY)

def pconvert(path):
    return '/'.join(path.split(os.sep))

def localpath(path):
    return path.replace('/', '\\')

def normpath(path):
    return pconvert(os.path.normpath(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(os.path.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 preceed 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" % nulldev
    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)))

def statfiles(files):
    '''Stat each file in files and yield stat or None if file does not exist.
    Cluster and cache stat per directory to minimize number of OS stat calls.'''
    ncase = os.path.normcase
    dircache = {} # dirname -> filename -> status | None if file does not exist
    for nf in files:
        nf  = ncase(nf)
        dir, base = os.path.split(nf)
        if not dir:
            dir = '.'
        cache = dircache.get(dir, None)
        if cache is None:
            try:
                dmap = dict([(ncase(n), s)
                    for n, k, s in osutil.listdir(dir, True)])
            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 termwidth():
    # cmd.exe does not handle CR like a unix console, the CR is
    # counted in the line length. On 80 columns consoles, if 80
    # characters are written, the following CR won't apply on the
    # current line but on the new one. Keep room for it.
    return 79

def groupmembers(name):
    # Don't support groups on Windows for now
    raise KeyError()

def isexec(f):
    return False

from win32 import *

class cachestat(object):
    def __init__(self, path):
        pass

    def cacheable(self):
        return False

expandglobs = True