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1 """Extended file operations available in POSIX. |
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2 |
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3 f = posixfile.open(filename, [mode, [bufsize]]) |
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4 will create a new posixfile object |
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5 |
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6 f = posixfile.fileopen(fileobject) |
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7 will create a posixfile object from a builtin file object |
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8 |
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9 f.file() |
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10 will return the original builtin file object |
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11 |
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12 f.dup() |
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13 will return a new file object based on a new filedescriptor |
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14 |
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15 f.dup2(fd) |
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16 will return a new file object based on the given filedescriptor |
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17 |
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18 f.flags(mode) |
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19 will turn on the associated flag (merge) |
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20 mode can contain the following characters: |
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21 |
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22 (character representing a flag) |
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23 a append only flag |
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24 c close on exec flag |
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25 n no delay flag |
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26 s synchronization flag |
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27 (modifiers) |
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28 ! turn flags 'off' instead of default 'on' |
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29 = copy flags 'as is' instead of default 'merge' |
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30 ? return a string in which the characters represent the flags |
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31 that are set |
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32 |
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33 note: - the '!' and '=' modifiers are mutually exclusive. |
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34 - the '?' modifier will return the status of the flags after they |
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35 have been changed by other characters in the mode string |
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36 |
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37 f.lock(mode [, len [, start [, whence]]]) |
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38 will (un)lock a region |
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39 mode can contain the following characters: |
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40 |
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41 (character representing type of lock) |
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42 u unlock |
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43 r read lock |
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44 w write lock |
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45 (modifiers) |
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46 | wait until the lock can be granted |
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47 ? return the first lock conflicting with the requested lock |
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48 or 'None' if there is no conflict. The lock returned is in the |
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49 format (mode, len, start, whence, pid) where mode is a |
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50 character representing the type of lock ('r' or 'w') |
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51 |
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52 note: - the '?' modifier prevents a region from being locked; it is |
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53 query only |
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54 """ |
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55 |
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56 |
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57 class _posixfile_: |
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58 """File wrapper class that provides extra POSIX file routines.""" |
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59 |
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60 states = ['open', 'closed'] |
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61 |
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62 # |
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63 # Internal routines |
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64 # |
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65 def __repr__(self): |
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66 file = self._file_ |
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67 return "<%s posixfile '%s', mode '%s' at %s>" % \ |
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68 (self.states[file.closed], file.name, file.mode, \ |
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69 hex(id(self))[2:]) |
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70 |
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71 # |
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72 # Initialization routines |
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73 # |
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74 def open(self, name, mode='r', bufsize=-1): |
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75 import __builtin__ |
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76 return self.fileopen(__builtin__.open(name, mode, bufsize)) |
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77 |
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78 def fileopen(self, file): |
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79 import types |
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80 if repr(type(file)) != "<type 'file'>": |
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81 raise TypeError, 'posixfile.fileopen() arg must be file object' |
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82 self._file_ = file |
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83 # Copy basic file methods |
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84 for maybemethod in dir(file): |
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85 if not maybemethod.startswith('_'): |
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86 attr = getattr(file, maybemethod) |
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87 if isinstance(attr, types.BuiltinMethodType): |
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88 setattr(self, maybemethod, attr) |
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89 return self |
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90 |
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91 # |
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92 # New methods |
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93 # |
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94 def file(self): |
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95 return self._file_ |
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96 |
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97 def dup(self): |
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98 import posix |
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99 |
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100 if not hasattr(posix, 'fdopen'): |
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101 raise AttributeError, 'dup() method unavailable' |
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102 |
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103 return posix.fdopen(posix.dup(self._file_.fileno()), self._file_.mode) |
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104 |
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105 def dup2(self, fd): |
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106 import posix |
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107 |
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108 if not hasattr(posix, 'fdopen'): |
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109 raise AttributeError, 'dup() method unavailable' |
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110 |
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111 posix.dup2(self._file_.fileno(), fd) |
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112 return posix.fdopen(fd, self._file_.mode) |
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113 |
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114 def flags(self, *which): |
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115 import fcntl, os |
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116 |
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117 if which: |
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118 if len(which) > 1: |
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119 raise TypeError, 'Too many arguments' |
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120 which = which[0] |
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121 else: which = '?' |
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122 |
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123 l_flags = 0 |
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124 if 'n' in which: l_flags = l_flags | os.O_NDELAY |
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125 if 'a' in which: l_flags = l_flags | os.O_APPEND |
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126 if 's' in which: l_flags = l_flags | os.O_SYNC |
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127 |
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128 file = self._file_ |
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129 |
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130 if '=' not in which: |
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131 cur_fl = fcntl.fcntl(file.fileno(), fcntl.F_GETFL, 0) |
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132 if '!' in which: l_flags = cur_fl & ~ l_flags |
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133 else: l_flags = cur_fl | l_flags |
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134 |
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135 l_flags = fcntl.fcntl(file.fileno(), fcntl.F_SETFL, l_flags) |
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136 |
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137 if 'c' in which: |
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138 arg = ('!' not in which) # 0 is don't, 1 is do close on exec |
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139 l_flags = fcntl.fcntl(file.fileno(), fcntl.F_SETFD, arg) |
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140 |
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141 if '?' in which: |
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142 which = '' # Return current flags |
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143 l_flags = fcntl.fcntl(file.fileno(), fcntl.F_GETFL, 0) |
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144 if os.O_APPEND & l_flags: which = which + 'a' |
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145 if fcntl.fcntl(file.fileno(), fcntl.F_GETFD, 0) & 1: |
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146 which = which + 'c' |
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147 if os.O_NDELAY & l_flags: which = which + 'n' |
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148 if os.O_SYNC & l_flags: which = which + 's' |
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149 return which |
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150 |
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151 def lock(self, how, *args): |
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152 import struct, fcntl |
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153 |
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154 if 'w' in how: l_type = fcntl.F_WRLCK |
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155 elif 'r' in how: l_type = fcntl.F_RDLCK |
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156 elif 'u' in how: l_type = fcntl.F_UNLCK |
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157 else: raise TypeError, 'no type of lock specified' |
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158 |
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159 if '|' in how: cmd = fcntl.F_SETLKW |
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160 elif '?' in how: cmd = fcntl.F_GETLK |
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161 else: cmd = fcntl.F_SETLK |
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162 |
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163 l_whence = 0 |
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164 l_start = 0 |
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165 l_len = 0 |
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166 |
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167 if len(args) == 1: |
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168 l_len = args[0] |
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169 elif len(args) == 2: |
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170 l_len, l_start = args |
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171 elif len(args) == 3: |
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172 l_len, l_start, l_whence = args |
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173 elif len(args) > 3: |
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174 raise TypeError, 'too many arguments' |
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175 |
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176 # Hack by davem@magnet.com to get locking to go on freebsd; |
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177 # additions for AIX by Vladimir.Marangozov@imag.fr |
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178 import sys, os |
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179 if sys.platform in ('netbsd1', |
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180 'openbsd2', |
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181 'freebsd2', 'freebsd3', 'freebsd4', 'freebsd5', |
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182 'freebsd6', 'freebsd7', |
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183 'bsdos2', 'bsdos3', 'bsdos4'): |
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184 flock = struct.pack('lxxxxlxxxxlhh', \ |
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185 l_start, l_len, os.getpid(), l_type, l_whence) |
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186 elif sys.platform in ('aix3', 'aix4'): |
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187 flock = struct.pack('hhlllii', \ |
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188 l_type, l_whence, l_start, l_len, 0, 0, 0) |
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189 else: |
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190 flock = struct.pack('hhllhh', \ |
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191 l_type, l_whence, l_start, l_len, 0, 0) |
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192 |
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193 flock = fcntl.fcntl(self._file_.fileno(), cmd, flock) |
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194 |
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195 if '?' in how: |
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196 if sys.platform in ('netbsd1', |
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197 'openbsd2', |
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198 'freebsd2', 'freebsd3', 'freebsd4', 'freebsd5', |
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199 'bsdos2', 'bsdos3', 'bsdos4'): |
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200 l_start, l_len, l_pid, l_type, l_whence = \ |
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201 struct.unpack('lxxxxlxxxxlhh', flock) |
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202 elif sys.platform in ('aix3', 'aix4'): |
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203 l_type, l_whence, l_start, l_len, l_sysid, l_pid, l_vfs = \ |
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204 struct.unpack('hhlllii', flock) |
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205 elif sys.platform == "linux2": |
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206 l_type, l_whence, l_start, l_len, l_pid, l_sysid = \ |
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207 struct.unpack('hhllhh', flock) |
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208 else: |
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209 l_type, l_whence, l_start, l_len, l_sysid, l_pid = \ |
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210 struct.unpack('hhllhh', flock) |
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211 |
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212 if l_type != fcntl.F_UNLCK: |
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213 if l_type == fcntl.F_RDLCK: |
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214 return 'r', l_len, l_start, l_whence, l_pid |
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215 else: |
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216 return 'w', l_len, l_start, l_whence, l_pid |
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217 |
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218 def open(name, mode='r', bufsize=-1): |
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219 """Public routine to open a file as a posixfile object.""" |
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220 return _posixfile_().open(name, mode, bufsize) |
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221 |
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222 def fileopen(file): |
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223 """Public routine to get a posixfile object from a Python file object.""" |
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224 return _posixfile_().fileopen(file) |
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225 |
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226 # |
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227 # Constants |
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228 # |
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229 SEEK_SET = 0 |
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230 SEEK_CUR = 1 |
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231 SEEK_END = 2 |
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232 |
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233 # |
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234 # End of posixfile.py |
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235 # |