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1 #
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2 # ElementTree
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3 # $Id: ElementInclude.py 3375 2008-02-13 08:05:08Z fredrik $
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4 #
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5 # limited xinclude support for element trees
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6 #
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7 # history:
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8 # 2003-08-15 fl created
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9 # 2003-11-14 fl fixed default loader
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10 #
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11 # Copyright (c) 2003-2004 by Fredrik Lundh. All rights reserved.
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12 #
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13 # fredrik@pythonware.com
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14 # http://www.pythonware.com
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15 #
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16 # --------------------------------------------------------------------
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17 # The ElementTree toolkit is
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18 #
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19 # Copyright (c) 1999-2008 by Fredrik Lundh
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20 #
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21 # By obtaining, using, and/or copying this software and/or its
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22 # associated documentation, you agree that you have read, understood,
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23 # and will comply with the following terms and conditions:
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24 #
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25 # Permission to use, copy, modify, and distribute this software and
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26 # its associated documentation for any purpose and without fee is
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27 # hereby granted, provided that the above copyright notice appears in
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28 # all copies, and that both that copyright notice and this permission
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29 # notice appear in supporting documentation, and that the name of
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30 # Secret Labs AB or the author not be used in advertising or publicity
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31 # pertaining to distribution of the software without specific, written
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32 # prior permission.
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33 #
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34 # SECRET LABS AB AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD
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35 # TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANT-
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36 # ABILITY AND FITNESS. IN NO EVENT SHALL SECRET LABS AB OR THE AUTHOR
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37 # BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY
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38 # DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
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39 # WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
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40 # ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
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41 # OF THIS SOFTWARE.
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42 # --------------------------------------------------------------------
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43
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44 # Licensed to PSF under a Contributor Agreement.
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45 # See http://www.python.org/psf/license for licensing details.
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46
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47 ##
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48 # Limited XInclude support for the ElementTree package.
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49 ##
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50
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51 import copy
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52 from . import ElementTree
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53
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54 XINCLUDE = "{http://www.w3.org/2001/XInclude}"
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55
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56 XINCLUDE_INCLUDE = XINCLUDE + "include"
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57 XINCLUDE_FALLBACK = XINCLUDE + "fallback"
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58
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59 ##
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60 # Fatal include error.
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61
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62 class FatalIncludeError(SyntaxError):
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63 pass
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64
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65 ##
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66 # Default loader. This loader reads an included resource from disk.
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67 #
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68 # @param href Resource reference.
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69 # @param parse Parse mode. Either "xml" or "text".
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70 # @param encoding Optional text encoding (UTF-8 by default for "text").
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71 # @return The expanded resource. If the parse mode is "xml", this
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72 # is an ElementTree instance. If the parse mode is "text", this
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73 # is a Unicode string. If the loader fails, it can return None
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74 # or raise an OSError exception.
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75 # @throws OSError If the loader fails to load the resource.
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76
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77 def default_loader(href, parse, encoding=None):
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78 if parse == "xml":
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79 with open(href, 'rb') as file:
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80 data = ElementTree.parse(file).getroot()
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81 else:
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82 if not encoding:
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83 encoding = 'UTF-8'
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84 with open(href, 'r', encoding=encoding) as file:
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85 data = file.read()
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86 return data
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87
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88 ##
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89 # Expand XInclude directives.
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90 #
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91 # @param elem Root element.
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92 # @param loader Optional resource loader. If omitted, it defaults
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93 # to {@link default_loader}. If given, it should be a callable
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94 # that implements the same interface as <b>default_loader</b>.
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95 # @throws FatalIncludeError If the function fails to include a given
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96 # resource, or if the tree contains malformed XInclude elements.
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97 # @throws OSError If the function fails to load a given resource.
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98
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99 def include(elem, loader=None):
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100 if loader is None:
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101 loader = default_loader
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102 # look for xinclude elements
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103 i = 0
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104 while i < len(elem):
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105 e = elem[i]
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106 if e.tag == XINCLUDE_INCLUDE:
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107 # process xinclude directive
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108 href = e.get("href")
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109 parse = e.get("parse", "xml")
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110 if parse == "xml":
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111 node = loader(href, parse)
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112 if node is None:
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113 raise FatalIncludeError(
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114 "cannot load %r as %r" % (href, parse)
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115 )
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116 node = copy.copy(node)
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117 if e.tail:
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118 node.tail = (node.tail or "") + e.tail
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119 elem[i] = node
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120 elif parse == "text":
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121 text = loader(href, parse, e.get("encoding"))
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122 if text is None:
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123 raise FatalIncludeError(
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124 "cannot load %r as %r" % (href, parse)
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125 )
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126 if i:
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127 node = elem[i-1]
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128 node.tail = (node.tail or "") + text + (e.tail or "")
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129 else:
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130 elem.text = (elem.text or "") + text + (e.tail or "")
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131 del elem[i]
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132 continue
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133 else:
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134 raise FatalIncludeError(
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135 "unknown parse type in xi:include tag (%r)" % parse
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136 )
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137 elif e.tag == XINCLUDE_FALLBACK:
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138 raise FatalIncludeError(
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139 "xi:fallback tag must be child of xi:include (%r)" % e.tag
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140 )
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141 else:
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142 include(e, loader)
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143 i = i + 1
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