"""

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, incorporated herein by

reference.

"""

from i18n import _

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

posixfile = file

nulldev = '/dev/null'

normpath = os.path.normpath

samestat = os.path.samestat

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 rcfiles(path):

    rcs = [os.path.join(path, 'hgrc')]

    rcdir = os.path.join(path, 'hgrc.d')

    try:

        rcs.extend([os.path.join(rcdir, f)

                    for f, kind in osutil.listdir(rcdir)

                    if f.endswith(".rc")])

    except OSError:

        pass

    return rcs

def system_rcpath():

    path = []

    # old mod_python does not set sys.argv

    if len(getattr(sys, 'argv', [])) > 0:

        path.extend(rcfiles(os.path.dirname(sys.argv[0]) +

                              '/../etc/mercurial'))

    path.extend(rcfiles('/etc/mercurial'))

    return path

def user_rcpath():

    return [os.path.expanduser('~/.hgrc')]

def parse_patch_output(output_line):

    """parses the output produced by patch and returns the file name"""

    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 is_exec(f):

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

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

def set_flags(f, l, x):

    s = os.lstat(f).st_mode

    if l:

        if not stat.S_ISLNK(s):

            # switch file to link

            data = file(f).read()

            os.unlink(f)

            try:

                os.symlink(data, f)

            except:

                # failed to make a link, rewrite file

                file(f, "w").write(data)

        # no chmod needed at this point

        return

    if stat.S_ISLNK(s):

        # switch link to file

        data = os.readlink(f)

        os.unlink(f)

        file(f, "w").write(data)

        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 set_binary(fd):

    pass

def pconvert(path):

    return path

def localpath(path):

    return path

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 explain_exit(code):

    """return a 2-tuple (desc, code) describing a process's status"""

    if os.WIFEXITED(code):

        val = os.WEXITSTATUS(code)

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

    elif os.WIFSIGNALED(code):

        val = os.WTERMSIG(code)

        return _("killed by signal %d") % val, val

    elif os.WIFSTOPPED(code):

        val = os.WSTOPSIG(code)

        return _("stopped by signal %d") % val, val

    raise ValueError(_("invalid exit code"))

def isowner(fp, st=None):

    """Return True if the file object f belongs to the current user.

    The return value of a util.fstat(f) may be passed as the st argument.

    """

    if st is None:

        st = fstat(fp)

    return st.st_uid == os.getuid()

def find_exe(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 set_signal_handler():

    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 expand_glob(pats):

    '''On Windows, expand the implicit globs in a list of patterns'''

    return list(pats)

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)