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1 | 1 | # demandimport.py - global demand-loading of modules for Mercurial |
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2 | 2 | # |
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3 | 3 | # Copyright 2006, 2007 Matt Mackall <mpm@selenic.com> |
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4 | 4 | # |
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5 | 5 | # This software may be used and distributed according to the terms of the |
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6 | 6 | # GNU General Public License version 2 or any later version. |
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7 | 7 | |
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8 | 8 | ''' |
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9 | 9 | demandimport - automatic demandloading of modules |
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10 | 10 | |
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11 | 11 | To enable this module, do: |
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12 | 12 | |
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13 | 13 | import demandimport; demandimport.enable() |
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14 | 14 | |
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15 | 15 | Imports of the following forms will be demand-loaded: |
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16 | 16 | |
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17 | 17 | import a, b.c |
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18 | 18 | import a.b as c |
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19 | 19 | from a import b,c # a will be loaded immediately |
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20 | 20 | |
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21 | 21 | These imports will not be delayed: |
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22 | 22 | |
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23 | 23 | from a import * |
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24 | 24 | b = __import__(a) |
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25 | 25 | ''' |
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26 | 26 | |
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27 | 27 | import __builtin__ |
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28 | 28 | _origimport = __import__ |
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29 | 29 | |
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30 | 30 | class _demandmod(object): |
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31 | 31 | """module demand-loader and proxy""" |
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32 | 32 | def __init__(self, name, globals, locals): |
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33 | 33 | if '.' in name: |
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34 | 34 | head, rest = name.split('.', 1) |
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35 | 35 | after = [rest] |
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36 | 36 | else: |
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37 | 37 | head = name |
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38 | 38 | after = [] |
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39 | 39 | object.__setattr__(self, "_data", (head, globals, locals, after)) |
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40 | 40 | object.__setattr__(self, "_module", None) |
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41 | 41 | def _extend(self, name): |
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42 | 42 | """add to the list of submodules to load""" |
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43 | 43 | self._data[3].append(name) |
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44 | 44 | def _load(self): |
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45 | 45 | if not self._module: |
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46 | 46 | head, globals, locals, after = self._data |
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47 | 47 | mod = _origimport(head, globals, locals) |
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48 | 48 | # load submodules |
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49 | 49 | def subload(mod, p): |
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50 | 50 | h, t = p, None |
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51 | 51 | if '.' in p: |
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52 | 52 | h, t = p.split('.', 1) |
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53 | 53 | if not hasattr(mod, h): |
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54 | 54 | setattr(mod, h, _demandmod(p, mod.__dict__, mod.__dict__)) |
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55 | 55 | elif t: |
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56 | 56 | subload(getattr(mod, h), t) |
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57 | 57 | |
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58 | 58 | for x in after: |
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59 | 59 | subload(mod, x) |
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60 | 60 | |
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61 | 61 | # are we in the locals dictionary still? |
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62 | 62 | if locals and locals.get(head) == self: |
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63 | 63 | locals[head] = mod |
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64 | 64 | object.__setattr__(self, "_module", mod) |
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65 | 65 | |
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66 | 66 | def __repr__(self): |
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67 | 67 | if self._module: |
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68 | 68 | return "<proxied module '%s'>" % self._data[0] |
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69 | 69 | return "<unloaded module '%s'>" % self._data[0] |
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70 | 70 | def __call__(self, *args, **kwargs): |
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71 | 71 | raise TypeError("%s object is not callable" % repr(self)) |
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72 | 72 | def __getattribute__(self, attr): |
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73 | 73 | if attr in ('_data', '_extend', '_load', '_module'): |
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74 | 74 | return object.__getattribute__(self, attr) |
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75 | 75 | self._load() |
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76 | 76 | return getattr(self._module, attr) |
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77 | 77 | def __setattr__(self, attr, val): |
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78 | 78 | self._load() |
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79 | 79 | setattr(self._module, attr, val) |
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80 | 80 | |
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81 | 81 | def _demandimport(name, globals=None, locals=None, fromlist=None, level=-1): |
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82 | 82 | if not locals or name in ignore or fromlist == ('*',): |
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83 | 83 | # these cases we can't really delay |
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84 | 84 | if level == -1: |
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85 | 85 | return _origimport(name, globals, locals, fromlist) |
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86 | 86 | else: |
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87 | 87 | return _origimport(name, globals, locals, fromlist, level) |
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88 | 88 | elif not fromlist: |
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89 | 89 | # import a [as b] |
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90 | 90 | if '.' in name: # a.b |
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91 | 91 | base, rest = name.split('.', 1) |
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92 | 92 | # email.__init__ loading email.mime |
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93 | 93 | if globals and globals.get('__name__', None) == base: |
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94 | 94 | if level != -1: |
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95 | 95 | return _origimport(name, globals, locals, fromlist, level) |
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96 | 96 | else: |
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97 | 97 | return _origimport(name, globals, locals, fromlist) |
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98 | 98 | # if a is already demand-loaded, add b to its submodule list |
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99 | 99 | if base in locals: |
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100 | 100 | if isinstance(locals[base], _demandmod): |
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101 | 101 | locals[base]._extend(rest) |
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102 | 102 | return locals[base] |
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103 | 103 | return _demandmod(name, globals, locals) |
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104 | 104 | else: |
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105 | 105 | if level != -1: |
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106 | 106 | # from . import b,c,d or from .a import b,c,d |
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107 | 107 | return _origimport(name, globals, locals, fromlist, level) |
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108 | 108 | # from a import b,c,d |
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109 | 109 | mod = _origimport(name, globals, locals) |
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110 | 110 | # recurse down the module chain |
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111 | 111 | for comp in name.split('.')[1:]: |
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112 | 112 | if not hasattr(mod, comp): |
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113 | 113 | setattr(mod, comp, _demandmod(comp, mod.__dict__, mod.__dict__)) |
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114 | 114 | mod = getattr(mod, comp) |
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115 | 115 | for x in fromlist: |
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116 | 116 | # set requested submodules for demand load |
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117 | 117 | if not hasattr(mod, x): |
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118 | 118 | setattr(mod, x, _demandmod(x, mod.__dict__, locals)) |
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119 | 119 | return mod |
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120 | 120 | |
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121 | 121 | ignore = [ |
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122 | 122 | '_hashlib', |
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123 | 123 | '_xmlplus', |
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124 | 124 | 'fcntl', |
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125 | 125 | 'win32com.gen_py', |
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126 | 126 | '_winreg', # 2.7 mimetypes needs immediate ImportError |
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127 | 127 | 'pythoncom', |
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128 | 128 | # imported by tarfile, not available under Windows |
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129 | 129 | 'pwd', |
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130 | 130 | 'grp', |
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131 | 131 | # imported by profile, itself imported by hotshot.stats, |
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132 | 132 | # not available under Windows |
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133 | 133 | 'resource', |
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134 | 134 | # this trips up many extension authors |
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135 | 135 | 'gtk', |
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136 | 136 | # setuptools' pkg_resources.py expects "from __main__ import x" to |
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137 | 137 | # raise ImportError if x not defined |
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138 | 138 | '__main__', |
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139 | 139 | '_ssl', # conditional imports in the stdlib, issue1964 |
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140 | 'rfc822', | |
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141 | 'mimetools', | |
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140 | 142 | ] |
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141 | 143 | |
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142 | 144 | def enable(): |
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143 | 145 | "enable global demand-loading of modules" |
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144 | 146 | __builtin__.__import__ = _demandimport |
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145 | 147 | |
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146 | 148 | def disable(): |
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147 | 149 | "disable global demand-loading of modules" |
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148 | 150 | __builtin__.__import__ = _origimport |
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149 | 151 |
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