# 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 i18n import _

import os, sys, errno, stat, getpass, pwd, grp, tempfile

posixfile = open

nulldev = '/dev/null'

normpath = os.path.normpath

samestat = os.path.samestat

oslink = os.link

unlink = os.unlink

rename = os.rename

expandglobs = False

umask = os.umask(0)

os.umask(umask)

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 os.sys.platform == '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

    return port and ("%s -p %s" % (args, port)) or args

def isexec(f):

    """check whether a file is executable"""

    return (os.lstat(f).st_mode & 0100 != 0)

def setflags(f, l, x):

    s = os.lstat(f).st_mode

    if l:

        if not stat.S_ISLNK(s):

            # switch file to link

            fp = open(f)

            data = fp.read()

            fp.close()

            os.unlink(f)

            try:

                os.symlink(data, f)

            except OSError:

                # failed to make a link, rewrite file

                fp = open(f, "w")

                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)

        os.unlink(f)

        fp = open(f, "w")

        fp.write(data)

        fp.close()

        s = 0666 & ~umask # avoid restatting for chmod

    sx = s & 0100

    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 & 0444) >> 2 & ~umask)

    elif not x and sx:

        # Turn off all +x bits

        os.chmod(f, s & 0666)

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

        fh, fn = tempfile.mkstemp(dir=path, prefix='hg-checkexec-')

        try:

            os.close(fh)

            m = os.stat(fn).st_mode & 0777

            new_file_has_exec = m & EXECFLAGS

            os.chmod(fn, m ^ EXECFLAGS)

            exec_flags_cannot_flip = ((os.stat(fn).st_mode & 0777) == m)

        finally:

            os.unlink(fn)

    except (IOError, OSError):

        # we don't care, the user probably won't be able to commit anyway

        return False

    return not (new_file_has_exec or exec_flags_cannot_flip)

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

    name = tempfile.mktemp(dir=path, prefix='hg-checklink-')

    try:

        os.symlink(".", name)

        os.unlink(name)

        return True

    except (OSError, AttributeError):

        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.'''

    pass # on posix platforms, every path is ok

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

if sys.platform == 'darwin':

    import fcntl # only needed on darwin, missing on jython

    def realpath(path):

        '''

        Returns the true, canonical file system path equivalent to the given

        path.

        Equivalent means, in this case, resulting in the same, unique

        file system link to the path. Every file system entry, whether a file,

        directory, hard link or symbolic link or special, will have a single

        path preferred by the system, but may allow multiple, differing path

        lookups to point to it.

        Most regular UNIX file systems only allow a file system entry to be

        looked up by its distinct path. Obviously, this does not apply to case

        insensitive file systems, whether case preserving or not. The most

        complex issue to deal with is file systems transparently reencoding the

        path, such as the non-standard Unicode normalisation required for HFS+

        and HFSX.

        '''

        # Constants copied from /usr/include/sys/fcntl.h

        F_GETPATH = 50

        O_SYMLINK = 0x200000

        try:

            fd = os.open(path, O_SYMLINK)

        except OSError, err:

            if err.errno == errno.ENOENT:

                return path

            raise

        try:

            return fcntl.fcntl(fd, F_GETPATH, '\0' * 1024).rstrip('\0')

        finally:

            os.close(fd)

else:

    # Fallback to the likely inadequate Python builtin function.

    realpath = os.path.realpath

def shellquote(s):

    if os.sys.platform == 'OpenVMS':

        return '"%s"' % s

    else:

        return "'%s'" % s.replace("'", "'\\''")

def quotecommand(cmd):

    return cmd

def popen(command, mode='r'):

    return os.popen(command, mode)

def testpid(pid):

    '''return False if pid dead, True if running or not sure'''

    if os.sys.platform == 'OpenVMS':

        return True

    try:

        os.kill(pid, 0)

        return True

    except OSError, inst:

        return inst.errno != errno.ESRCH

def explainexit(code):

    """return a 2-tuple (desc, code) describing a subprocess status

    (codes from kill are negative - not os.system/wait encoding)"""

    if code >= 0:

        return _("exited with status %d") % code, code

    return _("killed by signal %d") % -code, -code

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 sys.platform == 'OpenVMS':

        return command

    def findexisting(executable):

        'Will return executable if existing file'

        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 None

def setsignalhandler():

    pass

def statfiles(files):

    'Stat each file in files and yield stat or None if file does not exist.'

    lstat = os.lstat

    for nf in files:

        try:

            st = lstat(nf)

        except OSError, err:

            if err.errno not in (errno.ENOENT, errno.ENOTDIR):

                raise

            st = None

        yield st

def getuser():

    '''return name of current user'''

    return 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 pwd.getpwuid(uid)[0]

    except KeyError:

        return str(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 termwidth():

    try:

        import termios, array, fcntl

        for dev in (sys.stderr, sys.stdout, sys.stdin):

            try:

                try:

                    fd = dev.fileno()

                except AttributeError:

                    continue

                if not os.isatty(fd):

                    continue

                arri = fcntl.ioctl(fd, termios.TIOCGWINSZ, '\0' * 8)

                width = array.array('h', arri)[1]

                if width > 0:

                    return width

            except ValueError:

                pass

            except IOError, e:

                if e[0] == errno.EINVAL:

                    pass

                else:

                    raise

    except ImportError:

        pass

    return 80

def makedir(path, notindexed):

    os.mkdir(path)

def unlinkpath(f):

    """unlink and remove the directory if it is empty"""

    os.unlink(f)

    # try removing directories that might now be empty

    try:

        os.removedirs(os.path.dirname(f))

    except OSError:

        pass

def lookupreg(key, name=None, scope=None):

    return None