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

#

#  Copyright 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 ctypes

import ctypes.util

import os

import socket

import stat as statmod

from . import (

    policy,

    pycompat,

)

modulepolicy = policy.policy

policynocffi = policy.policynocffi

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 listdirpure(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

ffi = None

if modulepolicy not in policynocffi and pycompat.sysplatform == 'darwin':

    try:

        from _osutil_cffi import ffi, lib

    except ImportError:

        if modulepolicy == 'cffi': # strict cffi import

            raise

if pycompat.sysplatform == 'darwin' and ffi is not None:

    listdir_batch_size = 4096

    # tweakable number, only affects performance, which chunks

    # of bytes do we get back from getattrlistbulk

    attrkinds = [None] * 20 # we need the max no for enum VXXX, 20 is plenty

    attrkinds[lib.VREG] = statmod.S_IFREG

    attrkinds[lib.VDIR] = statmod.S_IFDIR

    attrkinds[lib.VLNK] = statmod.S_IFLNK

    attrkinds[lib.VBLK] = statmod.S_IFBLK

    attrkinds[lib.VCHR] = statmod.S_IFCHR

    attrkinds[lib.VFIFO] = statmod.S_IFIFO

    attrkinds[lib.VSOCK] = statmod.S_IFSOCK

    class stat_res(object):

        def __init__(self, st_mode, st_mtime, st_size):

            self.st_mode = st_mode

            self.st_mtime = st_mtime

            self.st_size = st_size

    tv_sec_ofs = ffi.offsetof("struct timespec", "tv_sec")

    buf = ffi.new("char[]", listdir_batch_size)

    def listdirinternal(dfd, req, stat, skip):

        ret = []

        while True:

            r = lib.getattrlistbulk(dfd, req, buf, listdir_batch_size, 0)

            if r == 0:

                break

            if r == -1:

                raise OSError(ffi.errno, os.strerror(ffi.errno))

            cur = ffi.cast("val_attrs_t*", buf)

            for i in range(r):

                lgt = cur.length

                assert lgt == ffi.cast('uint32_t*', cur)[0]

                ofs = cur.name_info.attr_dataoffset

                str_lgt = cur.name_info.attr_length

                base_ofs = ffi.offsetof('val_attrs_t', 'name_info')

                name = str(ffi.buffer(ffi.cast("char*", cur) + base_ofs + ofs,

                           str_lgt - 1))

                tp = attrkinds[cur.obj_type]

                if name == "." or name == "..":

                    continue

                if skip == name and tp == statmod.S_ISDIR:

                    return []

                if stat:

                    mtime = cur.mtime.tv_sec

                    mode = (cur.accessmask & ~lib.S_IFMT)| tp

                    ret.append((name, tp, stat_res(st_mode=mode, st_mtime=mtime,

                                st_size=cur.datalength)))

                else:

                    ret.append((name, tp))

                cur = ffi.cast("val_attrs_t*", int(ffi.cast("intptr_t", cur))

                    + lgt)

        return ret

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

        req = ffi.new("struct attrlist*")

        req.bitmapcount = lib.ATTR_BIT_MAP_COUNT

        req.commonattr = (lib.ATTR_CMN_RETURNED_ATTRS |

                          lib.ATTR_CMN_NAME |

                          lib.ATTR_CMN_OBJTYPE |

                          lib.ATTR_CMN_ACCESSMASK |

                          lib.ATTR_CMN_MODTIME)

        req.fileattr = lib.ATTR_FILE_DATALENGTH

        dfd = lib.open(path, lib.O_RDONLY, 0)

        if dfd == -1:

            raise OSError(ffi.errno, os.strerror(ffi.errno))

        try:

            ret = listdirinternal(dfd, req, stat, skip)

        finally:

            try:

                lib.close(dfd)

            except BaseException:

                pass # we ignore all the errors from closing, not

                # much we can do about that

        return ret

else:

    listdir = listdirpure

if pycompat.osname != 'nt':

    posixfile = open

    _SCM_RIGHTS = 0x01

    _socklen_t = ctypes.c_uint

    if pycompat.sysplatform.startswith('linux'):

        # socket.h says "the type should be socklen_t but the definition of

        # the kernel is incompatible with this."

        _cmsg_len_t = ctypes.c_size_t

        _msg_controllen_t = ctypes.c_size_t

        _msg_iovlen_t = ctypes.c_size_t

    else:

        _cmsg_len_t = _socklen_t

        _msg_controllen_t = _socklen_t

        _msg_iovlen_t = ctypes.c_int

    class _iovec(ctypes.Structure):

        _fields_ = [

            (u'iov_base', ctypes.c_void_p),

            (u'iov_len', ctypes.c_size_t),

        ]

    class _msghdr(ctypes.Structure):

        _fields_ = [

            (u'msg_name', ctypes.c_void_p),

            (u'msg_namelen', _socklen_t),

            (u'msg_iov', ctypes.POINTER(_iovec)),

            (u'msg_iovlen', _msg_iovlen_t),

            (u'msg_control', ctypes.c_void_p),

            (u'msg_controllen', _msg_controllen_t),

            (u'msg_flags', ctypes.c_int),

        ]

    class _cmsghdr(ctypes.Structure):

        _fields_ = [

            (u'cmsg_len', _cmsg_len_t),

            (u'cmsg_level', ctypes.c_int),

            (u'cmsg_type', ctypes.c_int),

            (u'cmsg_data', ctypes.c_ubyte * 0),

        ]

    _libc = ctypes.CDLL(ctypes.util.find_library(u'c'), use_errno=True)

    _recvmsg = getattr(_libc, 'recvmsg', None)

    if _recvmsg:

        _recvmsg.restype = getattr(ctypes, 'c_ssize_t', ctypes.c_long)

        _recvmsg.argtypes = (ctypes.c_int, ctypes.POINTER(_msghdr),

                             ctypes.c_int)

    else:

        # recvmsg isn't always provided by libc; such systems are unsupported

        def _recvmsg(sockfd, msg, flags):

            raise NotImplementedError('unsupported platform')

    def _CMSG_FIRSTHDR(msgh):

        if msgh.msg_controllen < ctypes.sizeof(_cmsghdr):

            return

        cmsgptr = ctypes.cast(msgh.msg_control, ctypes.POINTER(_cmsghdr))

        return cmsgptr.contents

    # The pure version is less portable than the native version because the

    # handling of socket ancillary data heavily depends on C preprocessor.

    # Also, some length fields are wrongly typed in Linux kernel.

    def recvfds(sockfd):

        """receive list of file descriptors via socket"""

        dummy = (ctypes.c_ubyte * 1)()

        iov = _iovec(ctypes.cast(dummy, ctypes.c_void_p), ctypes.sizeof(dummy))

        cbuf = ctypes.create_string_buffer(256)

        msgh = _msghdr(None, 0,

                       ctypes.pointer(iov), 1,

                       ctypes.cast(cbuf, ctypes.c_void_p), ctypes.sizeof(cbuf),

                       0)

        r = _recvmsg(sockfd, ctypes.byref(msgh), 0)

        if r < 0:

            e = ctypes.get_errno()

            raise OSError(e, os.strerror(e))

        # assumes that the first cmsg has fds because it isn't easy to write

        # portable CMSG_NXTHDR() with ctypes.

        cmsg = _CMSG_FIRSTHDR(msgh)

        if not cmsg:

            return []

        if (cmsg.cmsg_level != socket.SOL_SOCKET or

            cmsg.cmsg_type != _SCM_RIGHTS):

            return []

        rfds = ctypes.cast(cmsg.cmsg_data, ctypes.POINTER(ctypes.c_int))

        rfdscount = ((cmsg.cmsg_len - _cmsghdr.cmsg_data.offset) /

                     ctypes.sizeof(ctypes.c_int))

        return [rfds[i] for i in xrange(rfdscount)]

else:

    import msvcrt

    _kernel32 = ctypes.windll.kernel32

    _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()

        raise IOError(err.errno, '%s: %s' % (name, err.strerror))

    class posixfile(object):

        '''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='r', bufsize=-1):

            if 'b' in mode:

                flags = _O_BINARY

            else:

                flags = _O_TEXT

            m0 = mode[0]

            if m0 == 'r' and '+' 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 == 'r':

                creation = _OPEN_EXISTING

            elif m0 == 'w':

                creation = _CREATE_ALWAYS

            elif m0 == 'a':

                creation = _OPEN_ALWAYS

                flags |= _O_APPEND

            else:

                raise ValueError("invalid mode: %s" % 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)

            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, r'name', name)

            object.__setattr__(self, r'_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):

            return self._file.__enter__()

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

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