reprlib.py 7.0 KB

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  1. """Redo the builtin repr() (representation) but with limits on most sizes."""
  2. __all__ = ["Repr", "repr", "recursive_repr"]
  3. import builtins
  4. from itertools import islice
  5. from _thread import get_ident
  6. def recursive_repr(fillvalue='...'):
  7. 'Decorator to make a repr function return fillvalue for a recursive call'
  8. def decorating_function(user_function):
  9. repr_running = set()
  10. def wrapper(self):
  11. key = id(self), get_ident()
  12. if key in repr_running:
  13. return fillvalue
  14. repr_running.add(key)
  15. try:
  16. result = user_function(self)
  17. finally:
  18. repr_running.discard(key)
  19. return result
  20. # Can't use functools.wraps() here because of bootstrap issues
  21. wrapper.__module__ = getattr(user_function, '__module__')
  22. wrapper.__doc__ = getattr(user_function, '__doc__')
  23. wrapper.__name__ = getattr(user_function, '__name__')
  24. wrapper.__qualname__ = getattr(user_function, '__qualname__')
  25. wrapper.__annotations__ = getattr(user_function, '__annotations__', {})
  26. wrapper.__type_params__ = getattr(user_function, '__type_params__', ())
  27. return wrapper
  28. return decorating_function
  29. class Repr:
  30. _lookup = {
  31. 'tuple': 'builtins',
  32. 'list': 'builtins',
  33. 'array': 'array',
  34. 'set': 'builtins',
  35. 'frozenset': 'builtins',
  36. 'deque': 'collections',
  37. 'dict': 'builtins',
  38. 'str': 'builtins',
  39. 'int': 'builtins'
  40. }
  41. def __init__(
  42. self, *, maxlevel=6, maxtuple=6, maxlist=6, maxarray=5, maxdict=4,
  43. maxset=6, maxfrozenset=6, maxdeque=6, maxstring=30, maxlong=40,
  44. maxother=30, fillvalue='...', indent=None,
  45. ):
  46. self.maxlevel = maxlevel
  47. self.maxtuple = maxtuple
  48. self.maxlist = maxlist
  49. self.maxarray = maxarray
  50. self.maxdict = maxdict
  51. self.maxset = maxset
  52. self.maxfrozenset = maxfrozenset
  53. self.maxdeque = maxdeque
  54. self.maxstring = maxstring
  55. self.maxlong = maxlong
  56. self.maxother = maxother
  57. self.fillvalue = fillvalue
  58. self.indent = indent
  59. def repr(self, x):
  60. return self.repr1(x, self.maxlevel)
  61. def repr1(self, x, level):
  62. cls = type(x)
  63. typename = cls.__name__
  64. if ' ' in typename:
  65. parts = typename.split()
  66. typename = '_'.join(parts)
  67. method = getattr(self, 'repr_' + typename, None)
  68. if method:
  69. # not defined in this class
  70. if typename not in self._lookup:
  71. return method(x, level)
  72. module = getattr(cls, '__module__', None)
  73. # defined in this class and is the module intended
  74. if module == self._lookup[typename]:
  75. return method(x, level)
  76. return self.repr_instance(x, level)
  77. def _join(self, pieces, level):
  78. if self.indent is None:
  79. return ', '.join(pieces)
  80. if not pieces:
  81. return ''
  82. indent = self.indent
  83. if isinstance(indent, int):
  84. if indent < 0:
  85. raise ValueError(
  86. f'Repr.indent cannot be negative int (was {indent!r})'
  87. )
  88. indent *= ' '
  89. try:
  90. sep = ',\n' + (self.maxlevel - level + 1) * indent
  91. except TypeError as error:
  92. raise TypeError(
  93. f'Repr.indent must be a str, int or None, not {type(indent)}'
  94. ) from error
  95. return sep.join(('', *pieces, ''))[1:-len(indent) or None]
  96. def _repr_iterable(self, x, level, left, right, maxiter, trail=''):
  97. n = len(x)
  98. if level <= 0 and n:
  99. s = self.fillvalue
  100. else:
  101. newlevel = level - 1
  102. repr1 = self.repr1
  103. pieces = [repr1(elem, newlevel) for elem in islice(x, maxiter)]
  104. if n > maxiter:
  105. pieces.append(self.fillvalue)
  106. s = self._join(pieces, level)
  107. if n == 1 and trail and self.indent is None:
  108. right = trail + right
  109. return '%s%s%s' % (left, s, right)
  110. def repr_tuple(self, x, level):
  111. return self._repr_iterable(x, level, '(', ')', self.maxtuple, ',')
  112. def repr_list(self, x, level):
  113. return self._repr_iterable(x, level, '[', ']', self.maxlist)
  114. def repr_array(self, x, level):
  115. if not x:
  116. return "array('%s')" % x.typecode
  117. header = "array('%s', [" % x.typecode
  118. return self._repr_iterable(x, level, header, '])', self.maxarray)
  119. def repr_set(self, x, level):
  120. if not x:
  121. return 'set()'
  122. x = _possibly_sorted(x)
  123. return self._repr_iterable(x, level, '{', '}', self.maxset)
  124. def repr_frozenset(self, x, level):
  125. if not x:
  126. return 'frozenset()'
  127. x = _possibly_sorted(x)
  128. return self._repr_iterable(x, level, 'frozenset({', '})',
  129. self.maxfrozenset)
  130. def repr_deque(self, x, level):
  131. return self._repr_iterable(x, level, 'deque([', '])', self.maxdeque)
  132. def repr_dict(self, x, level):
  133. n = len(x)
  134. if n == 0:
  135. return '{}'
  136. if level <= 0:
  137. return '{' + self.fillvalue + '}'
  138. newlevel = level - 1
  139. repr1 = self.repr1
  140. pieces = []
  141. for key in islice(_possibly_sorted(x), self.maxdict):
  142. keyrepr = repr1(key, newlevel)
  143. valrepr = repr1(x[key], newlevel)
  144. pieces.append('%s: %s' % (keyrepr, valrepr))
  145. if n > self.maxdict:
  146. pieces.append(self.fillvalue)
  147. s = self._join(pieces, level)
  148. return '{%s}' % (s,)
  149. def repr_str(self, x, level):
  150. s = builtins.repr(x[:self.maxstring])
  151. if len(s) > self.maxstring:
  152. i = max(0, (self.maxstring-3)//2)
  153. j = max(0, self.maxstring-3-i)
  154. s = builtins.repr(x[:i] + x[len(x)-j:])
  155. s = s[:i] + self.fillvalue + s[len(s)-j:]
  156. return s
  157. def repr_int(self, x, level):
  158. s = builtins.repr(x) # XXX Hope this isn't too slow...
  159. if len(s) > self.maxlong:
  160. i = max(0, (self.maxlong-3)//2)
  161. j = max(0, self.maxlong-3-i)
  162. s = s[:i] + self.fillvalue + s[len(s)-j:]
  163. return s
  164. def repr_instance(self, x, level):
  165. try:
  166. s = builtins.repr(x)
  167. # Bugs in x.__repr__() can cause arbitrary
  168. # exceptions -- then make up something
  169. except Exception:
  170. return '<%s instance at %#x>' % (x.__class__.__name__, id(x))
  171. if len(s) > self.maxother:
  172. i = max(0, (self.maxother-3)//2)
  173. j = max(0, self.maxother-3-i)
  174. s = s[:i] + self.fillvalue + s[len(s)-j:]
  175. return s
  176. def _possibly_sorted(x):
  177. # Since not all sequences of items can be sorted and comparison
  178. # functions may raise arbitrary exceptions, return an unsorted
  179. # sequence in that case.
  180. try:
  181. return sorted(x)
  182. except Exception:
  183. return list(x)
  184. aRepr = Repr()
  185. repr = aRepr.repr