# osutil.py - pure Python version of osutil.c

#

#  Copyright 2009 Olivia Mackall <olivia@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.

import ctypes

import ctypes.util

import os

import stat as statmod

from .. import (

    encoding,

    pycompat,

)

def _mode_to_kind(mode):

    if statmod.S_ISREG(mode):

        return statmod.S_IFREG

    if statmod.S_ISDIR(mode):

        return statmod.S_IFDIR

    if statmod.S_ISLNK(mode):

        return statmod.S_IFLNK

    if statmod.S_ISBLK(mode):

        return statmod.S_IFBLK

    if statmod.S_ISCHR(mode):

        return statmod.S_IFCHR

    if statmod.S_ISFIFO(mode):

        return statmod.S_IFIFO

    if statmod.S_ISSOCK(mode):

        return statmod.S_IFSOCK

    return mode

def listdir(path, stat=False, skip=None):

    """listdir(path, stat=False) -> list_of_tuples

    Return a sorted list containing information about the entries

    in the directory.

    If stat is True, each element is a 3-tuple:

      (name, type, stat object)

    Otherwise, each element is a 2-tuple:

      (name, type)

    """

    result = []

    prefix = path

    if not prefix.endswith(pycompat.ossep):

        prefix += pycompat.ossep

    names = os.listdir(path)

    names.sort()

    for fn in names:

        st = os.lstat(prefix + fn)

        if fn == skip and statmod.S_ISDIR(st.st_mode):

            return []

        if stat:

            result.append((fn, _mode_to_kind(st.st_mode), st))

        else:

            result.append((fn, _mode_to_kind(st.st_mode)))

    return result

if not pycompat.iswindows:

    posixfile = open

else:

    import msvcrt

    _kernel32 = ctypes.windll.kernel32  # pytype: disable=module-attr

    _DWORD = ctypes.c_ulong

    _LPCSTR = _LPSTR = ctypes.c_char_p

    _HANDLE = ctypes.c_void_p

    _INVALID_HANDLE_VALUE = _HANDLE(-1).value

    # CreateFile

    _FILE_SHARE_READ = 0x00000001

    _FILE_SHARE_WRITE = 0x00000002

    _FILE_SHARE_DELETE = 0x00000004

    _CREATE_ALWAYS = 2

    _OPEN_EXISTING = 3

    _OPEN_ALWAYS = 4

    _GENERIC_READ = 0x80000000

    _GENERIC_WRITE = 0x40000000

    _FILE_ATTRIBUTE_NORMAL = 0x80

    # open_osfhandle flags

    _O_RDONLY = 0x0000

    _O_RDWR = 0x0002

    _O_APPEND = 0x0008

    _O_TEXT = 0x4000

    _O_BINARY = 0x8000

    # types of parameters of C functions used (required by pypy)

    _kernel32.CreateFileA.argtypes = [

        _LPCSTR,

        _DWORD,

        _DWORD,

        ctypes.c_void_p,

        _DWORD,

        _DWORD,

        _HANDLE,

    ]

    _kernel32.CreateFileA.restype = _HANDLE

    def _raiseioerror(name):

        err = ctypes.WinError()  # pytype: disable=module-attr

        raise IOError(

            err.errno, '%s: %s' % (encoding.strfromlocal(name), err.strerror)

        )

    class posixfile:

        """a file object aiming for POSIX-like semantics

        CPython's open() returns a file that was opened *without* setting the

        _FILE_SHARE_DELETE flag, which causes rename and unlink to abort.

        This even happens if any hardlinked copy of the file is in open state.

        We set _FILE_SHARE_DELETE here, so files opened with posixfile can be

        renamed and deleted while they are held open.

        Note that if a file opened with posixfile is unlinked, the file

        remains but cannot be opened again or be recreated under the same name,

        until all reading processes have closed the file."""

        def __init__(self, name, mode=b'r', bufsize=-1):

            if b'b' in mode:

                flags = _O_BINARY

            else:

                flags = _O_TEXT

            m0 = mode[0:1]

            if m0 == b'r' and b'+' not in mode:

                flags |= _O_RDONLY

                access = _GENERIC_READ

            else:

                # work around http://support.microsoft.com/kb/899149 and

                # set _O_RDWR for 'w' and 'a', even if mode has no '+'

                flags |= _O_RDWR

                access = _GENERIC_READ | _GENERIC_WRITE

            if m0 == b'r':

                creation = _OPEN_EXISTING

            elif m0 == b'w':

                creation = _CREATE_ALWAYS

            elif m0 == b'a':

                creation = _OPEN_ALWAYS

                flags |= _O_APPEND

            else:

                raise ValueError("invalid mode: %s" % pycompat.sysstr(mode))

            fh = _kernel32.CreateFileA(

                name,

                access,

                _FILE_SHARE_READ | _FILE_SHARE_WRITE | _FILE_SHARE_DELETE,

                None,

                creation,

                _FILE_ATTRIBUTE_NORMAL,

                None,

            )

            if fh == _INVALID_HANDLE_VALUE:

                _raiseioerror(name)

            fd = msvcrt.open_osfhandle(fh, flags)  # pytype: disable=module-attr

            if fd == -1:

                _kernel32.CloseHandle(fh)

                _raiseioerror(name)

            f = os.fdopen(fd, pycompat.sysstr(mode), bufsize)

            # unfortunately, f.name is '<fdopen>' at this point -- so we store

            # the name on this wrapper. We cannot just assign to f.name,

            # because that attribute is read-only.

            object.__setattr__(self, 'name', name)

            object.__setattr__(self, '_file', f)

        def __iter__(self):

            return self._file

        def __getattr__(self, name):

            return getattr(self._file, name)

        def __setattr__(self, name, value):

            """mimics the read-only attributes of Python file objects

            by raising 'TypeError: readonly attribute' if someone tries:

              f = posixfile('foo.txt')

              f.name = 'bla'

            """

            return self._file.__setattr__(name, value)

        def __enter__(self):

            self._file.__enter__()

            return self

        def __exit__(self, exc_type, exc_value, exc_tb):

            return self._file.__exit__(exc_type, exc_value, exc_tb)