# # Start of posixfile.py # # # Extended file operations # # 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_: 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:]) def __del__(self): self._file_.close() # # Initialization routines # def open(self, name, mode='r', bufsize=-1): import __builtin__ return self.fileopen(__builtin__.open(name, mode, bufsize)) def fileopen(self, file): if `type(file)` != "": raise TypeError, 'posixfile.fileopen() arg must be file object' self._file_ = file # Copy basic file methods for method in file.__methods__: setattr(self, method, getattr(file, method)) return self # # New methods # def file(self): return self._file_ def dup(self): import posix try: ignore = posix.fdopen except: raise AttributeError, 'dup() method unavailable' return posix.fdopen(posix.dup(self._file_.fileno()), self._file_.mode) def dup2(self, fd): import posix try: ignore = posix.fdopen except: raise AttributeError, 'dup() method unavailable' posix.dup2(self._file_.fileno(), fd) return posix.fdopen(fd, self._file_.mode) def flags(self, *which): import fcntl, FCNTL 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 | FCNTL.O_NDELAY if 'a' in which: l_flags = l_flags | FCNTL.O_APPEND if 's' in which: l_flags = l_flags | FCNTL.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 FCNTL.O_APPEND & l_flags: which = which + 'a' if fcntl.fcntl(file.fileno(), FCNTL.F_GETFD, 0) & 1: which = which + 'c' if FCNTL.O_NDELAY & l_flags: which = which + 'n' if FCNTL.O_SYNC & l_flags: which = which + 's' return which def lock(self, how, *args): import struct, fcntl, 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', 'freebsd2', 'freebsd3', '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', 'freebsd2', 'freebsd3', '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 # # Public routine to obtain a posixfile object # def open(name, mode='r', bufsize=-1): return _posixfile_().open(name, mode, bufsize) def fileopen(file): return _posixfile_().fileopen(file) # # Constants # SEEK_SET = 0 SEEK_CUR = 1 SEEK_END = 2 # # End of posixfile.py #