"""Extended file operations available in POSIX. f = posixfile.open(filename, [mode, [bufsize]])      will create a new posixfile object f = posixfile.fileopen(fileobject)      will create a posixfile object from a builtin file object f.file()      will return the original builtin file object f.dup()      will return a new file object based on a new filedescriptor f.dup2(fd)      will return a new file object based on the given filedescriptor f.flags(mode)      will turn on the associated flag (merge)      mode can contain the following characters:   (character representing a flag)      a       append only flag      c       close on exec flag      n       no delay flag      s       synchronization flag  (modifiers)      !       turn flags 'off' instead of default 'on'      =       copy flags 'as is' instead of default 'merge'      ?       return a string in which the characters represent the flags              that are set       note: - the '!' and '=' modifiers are mutually exclusive.            - the '?' modifier will return the status of the flags after they              have been changed by other characters in the mode string f.lock(mode [, len [, start [, whence]]])      will (un)lock a region      mode can contain the following characters:   (character representing type of lock)      u       unlock      r       read lock      w       write lock  (modifiers)      |       wait until the lock can be granted      ?       return the first lock conflicting with the requested lock              or 'None' if there is no conflict. The lock returned is in the              format (mode, len, start, whence, pid) where mode is a              character representing the type of lock ('r' or 'w')       note: - the '?' modifier prevents a region from being locked; it is              query only"""  class _posixfile_:    """File wrapper class that provides extra POSIX file routines."""     states = ['open', 'closed']     #    # Internal routines    #    def __repr__(self):        file = self._file_        return "<%s posixfile '%s', mode '%s' at %s>" % \                (self.states[file.closed], file.name, file.mode, \                 hex(id(self))[2:])     #    # Initialization routines    #    def open(self, name, mode='r', bufsize=-1):        import __builtin__        return self.fileopen(__builtin__.open(name, mode, bufsize))     def fileopen(self, file):        import types        if repr(type(file)) != "<type 'file'>":            raise TypeError, 'posixfile.fileopen() arg must be file object'        self._file_  = file        # Copy basic file methods        for maybemethod in dir(file):            if not maybemethod.startswith('_'):                attr = getattr(file, maybemethod)                if isinstance(attr, types.BuiltinMethodType):                    setattr(self, maybemethod, attr)        return self     #    # New methods    #    def file(self):        return self._file_     def dup(self):        import posix         if not hasattr(posix, 'fdopen'):            raise AttributeError, 'dup() method unavailable'         return posix.fdopen(posix.dup(self._file_.fileno()), self._file_.mode)     def dup2(self, fd):        import posix         if not hasattr(posix, 'fdopen'):            raise AttributeError, 'dup() method unavailable'         posix.dup2(self._file_.fileno(), fd)        return posix.fdopen(fd, self._file_.mode)     def flags(self, *which):        import fcntl, os         if which:            if len(which) > 1:                raise TypeError, 'Too many arguments'            which = which[0]        else: which = '?'         l_flags = 0        if 'n' in which: l_flags = l_flags | os.O_NDELAY        if 'a' in which: l_flags = l_flags | os.O_APPEND        if 's' in which: l_flags = l_flags | os.O_SYNC         file = self._file_         if '=' not in which:            cur_fl = fcntl.fcntl(file.fileno(), fcntl.F_GETFL, 0)            if '!' in which: l_flags = cur_fl & ~ l_flags            else: l_flags = cur_fl | l_flags         l_flags = fcntl.fcntl(file.fileno(), fcntl.F_SETFL, l_flags)         if 'c' in which:            arg = ('!' not in which)    # 0 is don't, 1 is do close on exec            l_flags = fcntl.fcntl(file.fileno(), fcntl.F_SETFD, arg)         if '?' in which:            which = ''                  # Return current flags            l_flags = fcntl.fcntl(file.fileno(), fcntl.F_GETFL, 0)            if os.O_APPEND & l_flags: which = which + 'a'            if fcntl.fcntl(file.fileno(), fcntl.F_GETFD, 0) & 1:                which = which + 'c'            if os.O_NDELAY & l_flags: which = which + 'n'            if os.O_SYNC & l_flags: which = which + 's'            return which     def lock(self, how, *args):        import struct, fcntl         if 'w' in how: l_type = fcntl.F_WRLCK        elif 'r' in how: l_type = fcntl.F_RDLCK        elif 'u' in how: l_type = fcntl.F_UNLCK        else: raise TypeError, 'no type of lock specified'         if '|' in how: cmd = fcntl.F_SETLKW        elif '?' in how: cmd = fcntl.F_GETLK        else: cmd = fcntl.F_SETLK         l_whence = 0        l_start = 0        l_len = 0         if len(args) == 1:            l_len = args[0]        elif len(args) == 2:            l_len, l_start = args        elif len(args) == 3:            l_len, l_start, l_whence = args        elif len(args) > 3:            raise TypeError, 'too many arguments'         # Hack by davem@magnet.com to get locking to go on freebsd;        # additions for AIX by Vladimir.Marangozov@imag.fr        import sys, os        if sys.platform in ('netbsd1',                            'openbsd2',                            'freebsd2', 'freebsd3', 'freebsd4', 'freebsd5',                            'freebsd6', 'freebsd7',                            'bsdos2', 'bsdos3', 'bsdos4'):            flock = struct.pack('lxxxxlxxxxlhh', \                  l_start, l_len, os.getpid(), l_type, l_whence)        elif sys.platform in ('aix3', 'aix4'):            flock = struct.pack('hhlllii', \                  l_type, l_whence, l_start, l_len, 0, 0, 0)        else:            flock = struct.pack('hhllhh', \                  l_type, l_whence, l_start, l_len, 0, 0)         flock = fcntl.fcntl(self._file_.fileno(), cmd, flock)         if '?' in how:            if sys.platform in ('netbsd1',                                'openbsd2',                                'freebsd2', 'freebsd3', 'freebsd4', 'freebsd5',                                'bsdos2', 'bsdos3', 'bsdos4'):                l_start, l_len, l_pid, l_type, l_whence = \                    struct.unpack('lxxxxlxxxxlhh', flock)            elif sys.platform in ('aix3', 'aix4'):                l_type, l_whence, l_start, l_len, l_sysid, l_pid, l_vfs = \                    struct.unpack('hhlllii', flock)            elif sys.platform == "linux2":                l_type, l_whence, l_start, l_len, l_pid, l_sysid = \                    struct.unpack('hhllhh', flock)            else:                l_type, l_whence, l_start, l_len, l_sysid, l_pid = \                    struct.unpack('hhllhh', flock)             if l_type != fcntl.F_UNLCK:                if l_type == fcntl.F_RDLCK:                    return 'r', l_len, l_start, l_whence, l_pid                else:                    return 'w', l_len, l_start, l_whence, l_pid def open(name, mode='r', bufsize=-1):    """Public routine to open a file as a posixfile object."""    return _posixfile_().open(name, mode, bufsize) def fileopen(file):    """Public routine to get a posixfile object from a Python file object."""    return _posixfile_().fileopen(file) ## Constants#SEEK_SET = 0SEEK_CUR = 1SEEK_END = 2 ## End of posixfile.py#