"""
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)