Guido van Rossum | 78f8dea | 1994-05-18 11:07:44 +0000 | [diff] [blame^] | 1 | # |
| 2 | # Start of posixfile.py |
| 3 | # |
| 4 | |
| 5 | # |
| 6 | # Extended file operations |
| 7 | # |
| 8 | # f = posixfile.open(filename, mode) |
| 9 | # |
| 10 | # f.file() |
| 11 | # will return the original builtin file object |
| 12 | # |
| 13 | # f.dup() |
| 14 | # will return a new file object based on a new filedescriptor |
| 15 | # |
| 16 | # f.dup2(fd) |
| 17 | # will return a new file object based on the given filedescriptor |
| 18 | # |
| 19 | # f.flags(mode) |
| 20 | # will turn on the associated flag (merge) |
| 21 | # mode can contain the following characters: |
| 22 | # |
| 23 | # (character representing a flag) |
| 24 | # a append only flag |
| 25 | # c close on exec flag |
| 26 | # n no delay flag |
| 27 | # s synchronization flag |
| 28 | # (modifiers) |
| 29 | # ! turn flags 'off' instead of default 'on' |
| 30 | # = copy flags 'as is' instead of default 'merge' |
| 31 | # ? return a string in which the characters represent the flags |
| 32 | # that are set |
| 33 | # |
| 34 | # note: - the '!' and '=' modifiers are mutually exclusive. |
| 35 | # - the '?' modifier will return the status of the flags after they |
| 36 | # have been changed by other characters in the mode string |
| 37 | # |
| 38 | # f.lock(mode [, len [, start [, whence]]]) |
| 39 | # will (un)lock a region |
| 40 | # mode can contain the following characters: |
| 41 | # |
| 42 | # (character representing type of lock) |
| 43 | # u unlock |
| 44 | # r read lock |
| 45 | # w write lock |
| 46 | # (modifiers) |
| 47 | # | wait until the lock can be granted |
| 48 | # ? return the first lock conflicting with the requested lock |
| 49 | # or 'None' if there is no conflict. The lock returned is in the |
| 50 | # format (mode, len, start, whence, pid) where mode is a |
| 51 | # character representing the type of lock ('r' or 'w') |
| 52 | # |
| 53 | # note: - the '?' modifier prevents a region from being locked; it is |
| 54 | # query only |
| 55 | # |
| 56 | |
| 57 | class _posixfile_: |
| 58 | # |
| 59 | # Internal routines |
| 60 | # |
| 61 | def __repr__(self): |
| 62 | return repr(self._file_) |
| 63 | |
| 64 | def __del__(self): |
| 65 | self._file_.close() |
| 66 | |
| 67 | # |
| 68 | # Initialization routines |
| 69 | # |
| 70 | def open(self, name, mode): |
| 71 | import __builtin__ |
| 72 | |
| 73 | self._name_ = name |
| 74 | self._mode_ = mode |
| 75 | self._file_ = __builtin__.open(name, mode) |
| 76 | # Copy basic file methods |
| 77 | for method in self._file_.__methods__: |
| 78 | setattr(self, method, getattr(self._file_, method)) |
| 79 | return self |
| 80 | |
| 81 | # |
| 82 | # New methods |
| 83 | # |
| 84 | def file(self): |
| 85 | return self._file_ |
| 86 | |
| 87 | def dup(self): |
| 88 | import posix |
| 89 | |
| 90 | try: ignore = posix.fdopen |
| 91 | except: raise AttributeError, 'dup() method unavailable' |
| 92 | |
| 93 | return posix.fdopen(posix.dup(self._file_.fileno()), self._mode_) |
| 94 | |
| 95 | def dup2(self, fd): |
| 96 | import posix |
| 97 | |
| 98 | try: ignore = posix.fdopen |
| 99 | except: raise AttributeError, 'dup() method unavailable' |
| 100 | |
| 101 | posix.dup2(self._file_.fileno(), fd) |
| 102 | return posix.fdopen(fd, self._mode_) |
| 103 | |
| 104 | def flags(self, which): |
| 105 | import fcntl, FCNTL |
| 106 | |
| 107 | l_flags = 0 |
| 108 | if 'n' in which: l_flags = l_flags | FCNTL.O_NDELAY |
| 109 | if 'a' in which: l_flags = l_flags | FCNTL.O_APPEND |
| 110 | if 's' in which: l_flags = l_flags | FCNTL.O_SYNC |
| 111 | |
| 112 | if '=' not in which: |
| 113 | cur_fl = fcntl.fcntl(self._file_.fileno(), FCNTL.F_GETFL, 0) |
| 114 | if '!' in which: l_flags = cur_fl & ~ l_flags |
| 115 | else: l_flags = cur_fl | l_flags |
| 116 | |
| 117 | l_flags = fcntl.fcntl(self._file_.fileno(), FCNTL.F_SETFL, l_flags) |
| 118 | |
| 119 | if 'c' in which: |
| 120 | arg = ('!' not in which) # 1 is close |
| 121 | l_flags = fcntl.fcntl(self._file_.fileno(), FCNTL.F_SETFD, arg) |
| 122 | |
| 123 | if '?' in which: |
| 124 | which = '' |
| 125 | l_flags = fcntl.fcntl(self._file_.fileno(), FCNTL.F_GETFL, 0) |
| 126 | if FCNTL.O_APPEND & l_flags: which = which + 'a' |
| 127 | if fcntl.fcntl(self._file_.fileno(), FCNTL.F_GETFD, 0) & 1: |
| 128 | which = which + 'c' |
| 129 | if FCNTL.O_NDELAY & l_flags: which = which + 'n' |
| 130 | if FCNTL.O_SYNC & l_flags: which = which + 's' |
| 131 | return which |
| 132 | |
| 133 | def lock(self, how, *args): |
| 134 | import struct, fcntl, FCNTL |
| 135 | |
| 136 | if 'w' in how: l_type = FCNTL.F_WRLCK |
| 137 | elif 'r' in how: l_type = FCNTL.F_WRLCK |
| 138 | elif 'u' in how: l_type = FCNTL.F_UNLCK |
| 139 | else: raise TypeError, 'no type of lock specified' |
| 140 | |
| 141 | if '|' in how: cmd = FCNTL.F_SETLKW |
| 142 | elif '?' in how: cmd = FCNTL.F_GETLK |
| 143 | else: cmd = FCNTL.F_SETLK |
| 144 | |
| 145 | l_whence = 0 |
| 146 | l_start = 0 |
| 147 | l_len = 0 |
| 148 | |
| 149 | if len(args) == 1: |
| 150 | l_len = args[0] |
| 151 | elif len(args) == 2: |
| 152 | l_len, l_start = args |
| 153 | elif len(args) == 3: |
| 154 | l_len, l_start, l_whence = args |
| 155 | elif len(args) > 3: |
| 156 | raise TypeError, 'too many arguments' |
| 157 | |
| 158 | flock = struct.pack('hhllhh', l_type, l_whence, l_start, l_len, 0, 0) |
| 159 | flock = fcntl.fcntl(self._file_.fileno(), cmd, flock) |
| 160 | |
| 161 | if '?' in how: |
| 162 | l_type, l_whence, l_start, l_len, l_sysid, l_pid = \ |
| 163 | struct.unpack('hhllhh', flock) |
| 164 | if l_type != FCNTL.F_UNLCK: |
| 165 | if l_type == FCNTL.F_RDLCK: |
| 166 | return 'r', l_len, l_start, l_whence, l_pid |
| 167 | else: |
| 168 | return 'w', l_len, l_start, l_whence, l_pid |
| 169 | |
| 170 | # |
| 171 | # Public routine to obtain a posixfile object |
| 172 | # |
| 173 | def open(name, mode): |
| 174 | return _posixfile_().open(name, mode) |
| 175 | |
| 176 | # |
| 177 | # End of posixfile.py |
| 178 | # |