# 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,

)

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 ['/absolute/path/to/file',

    ...           'relative/path/to/file',

    ...           'file_alone',

    ...           'path/to/directory/',

    ...           '/multiple/path//separators',

    ...           '/file_at_root',

    ...           '///multiple_leading_separators_at_root',

    ...           '']:

    ...     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 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 & 0o100 != 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 = 0o666 & ~umask # avoid restatting for chmod

    sx = s & 0o100

    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

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

        try:

            os.close(fh)

            m = os.stat(fn).st_mode & 0o777

            new_file_has_exec = m & EXECFLAGS

            os.chmod(fn, m ^ EXECFLAGS)

            exec_flags_cannot_flip = ((os.stat(fn).st_mode & 0o777) == 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

    while True:

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

        try:

            fd = tempfile.NamedTemporaryFile(dir=path, prefix='hg-checklink-')

            try:

                os.symlink(os.path.basename(fd.name), name)

                os.unlink(name)

                return True

            except OSError as inst:

                # link creation might race, try again

                if inst[0] == errno.EEXIST:

                    continue

                raise

            finally:

                fd.close()

        except AttributeError:

            return False

        except OSError as inst:

            # sshfs might report failure while successfully creating the link

            if inst[0] == errno.EIO and os.path.exists(name):

                os.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.'''

    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

# 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 sys.platform == 'darwin':

    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('UPPER')

        'upper'

        >>> normcase('Caf\xc3\xa9')

        'cafe\\xcc\\x81'

        >>> normcase('\xc3\x89')

        'e\\xcc\\x81'

        >>> normcase('\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

                s += c

            u = s.decode('utf-8')

        # Decompose then lowercase (HFS+ technote specifies lower)

        enc = unicodedata.normalize('NFD', u).lower().encode('utf-8')

        # drop HFS+ ignored characters

        return encoding.hfsignoreclean(enc)

if sys.platform == '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] != os.sep):

            # 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] == os.sep:

                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 os.sys.platform == 'OpenVMS':

        return '"%s"' % s

    global _needsshellquote

    if _needsshellquote is None:

        _needsshellquote = re.compile(r'[^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 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 as 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.isfile(executable) and os.access(executable, os.X_OK):

            return executable

        return None

    if os.sep in command:

        return findexisting(command)

    if sys.platform == 'plan9':

        return findexisting(os.path.join('/bin', command))