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1 """A readline()-style interface to the parts of a multipart message. |
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2 |
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3 The MultiFile class makes each part of a multipart message "feel" like |
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4 an ordinary file, as long as you use fp.readline(). Allows recursive |
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5 use, for nested multipart messages. Probably best used together |
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6 with module mimetools. |
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7 |
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8 Suggested use: |
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9 |
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10 real_fp = open(...) |
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11 fp = MultiFile(real_fp) |
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12 |
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13 "read some lines from fp" |
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14 fp.push(separator) |
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15 while 1: |
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16 "read lines from fp until it returns an empty string" (A) |
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17 if not fp.next(): break |
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18 fp.pop() |
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19 "read remaining lines from fp until it returns an empty string" |
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20 |
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21 The latter sequence may be used recursively at (A). |
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22 It is also allowed to use multiple push()...pop() sequences. |
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23 |
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24 If seekable is given as 0, the class code will not do the bookkeeping |
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25 it normally attempts in order to make seeks relative to the beginning of the |
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26 current file part. This may be useful when using MultiFile with a non- |
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27 seekable stream object. |
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28 """ |
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29 from warnings import warn |
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30 warn("the multifile module has been deprecated since Python 2.5", |
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31 DeprecationWarning, stacklevel=2) |
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32 del warn |
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33 |
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34 __all__ = ["MultiFile","Error"] |
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35 |
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36 class Error(Exception): |
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37 pass |
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38 |
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39 class MultiFile: |
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40 |
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41 seekable = 0 |
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42 |
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43 def __init__(self, fp, seekable=1): |
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44 self.fp = fp |
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45 self.stack = [] |
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46 self.level = 0 |
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47 self.last = 0 |
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48 if seekable: |
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49 self.seekable = 1 |
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50 self.start = self.fp.tell() |
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51 self.posstack = [] |
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52 |
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53 def tell(self): |
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54 if self.level > 0: |
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55 return self.lastpos |
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56 return self.fp.tell() - self.start |
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57 |
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58 def seek(self, pos, whence=0): |
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59 here = self.tell() |
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60 if whence: |
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61 if whence == 1: |
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62 pos = pos + here |
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63 elif whence == 2: |
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64 if self.level > 0: |
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65 pos = pos + self.lastpos |
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66 else: |
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67 raise Error, "can't use whence=2 yet" |
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68 if not 0 <= pos <= here or \ |
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69 self.level > 0 and pos > self.lastpos: |
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70 raise Error, 'bad MultiFile.seek() call' |
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71 self.fp.seek(pos + self.start) |
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72 self.level = 0 |
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73 self.last = 0 |
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74 |
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75 def readline(self): |
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76 if self.level > 0: |
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77 return '' |
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78 line = self.fp.readline() |
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79 # Real EOF? |
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80 if not line: |
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81 self.level = len(self.stack) |
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82 self.last = (self.level > 0) |
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83 if self.last: |
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84 raise Error, 'sudden EOF in MultiFile.readline()' |
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85 return '' |
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86 assert self.level == 0 |
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87 # Fast check to see if this is just data |
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88 if self.is_data(line): |
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89 return line |
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90 else: |
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91 # Ignore trailing whitespace on marker lines |
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92 marker = line.rstrip() |
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93 # No? OK, try to match a boundary. |
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94 # Return the line (unstripped) if we don't. |
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95 for i, sep in enumerate(reversed(self.stack)): |
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96 if marker == self.section_divider(sep): |
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97 self.last = 0 |
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98 break |
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99 elif marker == self.end_marker(sep): |
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100 self.last = 1 |
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101 break |
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102 else: |
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103 return line |
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104 # We only get here if we see a section divider or EOM line |
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105 if self.seekable: |
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106 self.lastpos = self.tell() - len(line) |
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107 self.level = i+1 |
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108 if self.level > 1: |
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109 raise Error,'Missing endmarker in MultiFile.readline()' |
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110 return '' |
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111 |
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112 def readlines(self): |
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113 list = [] |
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114 while 1: |
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115 line = self.readline() |
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116 if not line: break |
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117 list.append(line) |
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118 return list |
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119 |
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120 def read(self): # Note: no size argument -- read until EOF only! |
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121 return ''.join(self.readlines()) |
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122 |
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123 def next(self): |
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124 while self.readline(): pass |
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125 if self.level > 1 or self.last: |
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126 return 0 |
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127 self.level = 0 |
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128 self.last = 0 |
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129 if self.seekable: |
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130 self.start = self.fp.tell() |
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131 return 1 |
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132 |
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133 def push(self, sep): |
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134 if self.level > 0: |
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135 raise Error, 'bad MultiFile.push() call' |
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136 self.stack.append(sep) |
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137 if self.seekable: |
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138 self.posstack.append(self.start) |
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139 self.start = self.fp.tell() |
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140 |
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141 def pop(self): |
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142 if self.stack == []: |
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143 raise Error, 'bad MultiFile.pop() call' |
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144 if self.level <= 1: |
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145 self.last = 0 |
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146 else: |
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147 abslastpos = self.lastpos + self.start |
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148 self.level = max(0, self.level - 1) |
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149 self.stack.pop() |
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150 if self.seekable: |
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151 self.start = self.posstack.pop() |
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152 if self.level > 0: |
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153 self.lastpos = abslastpos - self.start |
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154 |
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155 def is_data(self, line): |
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156 return line[:2] != '--' |
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157 |
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158 def section_divider(self, str): |
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159 return "--" + str |
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160 |
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161 def end_marker(self, str): |
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162 return "--" + str + "--" |