representer.py 17 KB

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  1. __all__ = ['BaseRepresenter', 'SafeRepresenter', 'Representer',
  2. 'RepresenterError']
  3. from error import *
  4. from nodes import *
  5. import datetime
  6. import sys, copy_reg, types
  7. class RepresenterError(YAMLError):
  8. pass
  9. class BaseRepresenter(object):
  10. yaml_representers = {}
  11. yaml_multi_representers = {}
  12. def __init__(self, default_style=None, default_flow_style=None):
  13. self.default_style = default_style
  14. self.default_flow_style = default_flow_style
  15. self.represented_objects = {}
  16. self.object_keeper = []
  17. self.alias_key = None
  18. def represent(self, data):
  19. node = self.represent_data(data)
  20. self.serialize(node)
  21. self.represented_objects = {}
  22. self.object_keeper = []
  23. self.alias_key = None
  24. def get_classobj_bases(self, cls):
  25. bases = [cls]
  26. for base in cls.__bases__:
  27. bases.extend(self.get_classobj_bases(base))
  28. return bases
  29. def represent_data(self, data):
  30. if self.ignore_aliases(data):
  31. self.alias_key = None
  32. else:
  33. self.alias_key = id(data)
  34. if self.alias_key is not None:
  35. if self.alias_key in self.represented_objects:
  36. node = self.represented_objects[self.alias_key]
  37. #if node is None:
  38. # raise RepresenterError("recursive objects are not allowed: %r" % data)
  39. return node
  40. #self.represented_objects[alias_key] = None
  41. self.object_keeper.append(data)
  42. data_types = type(data).__mro__
  43. if type(data) is types.InstanceType:
  44. data_types = self.get_classobj_bases(data.__class__)+list(data_types)
  45. if data_types[0] in self.yaml_representers:
  46. node = self.yaml_representers[data_types[0]](self, data)
  47. else:
  48. for data_type in data_types:
  49. if data_type in self.yaml_multi_representers:
  50. node = self.yaml_multi_representers[data_type](self, data)
  51. break
  52. else:
  53. if None in self.yaml_multi_representers:
  54. node = self.yaml_multi_representers[None](self, data)
  55. elif None in self.yaml_representers:
  56. node = self.yaml_representers[None](self, data)
  57. else:
  58. node = ScalarNode(None, unicode(data))
  59. #if alias_key is not None:
  60. # self.represented_objects[alias_key] = node
  61. return node
  62. def add_representer(cls, data_type, representer):
  63. if not 'yaml_representers' in cls.__dict__:
  64. cls.yaml_representers = cls.yaml_representers.copy()
  65. cls.yaml_representers[data_type] = representer
  66. add_representer = classmethod(add_representer)
  67. def add_multi_representer(cls, data_type, representer):
  68. if not 'yaml_multi_representers' in cls.__dict__:
  69. cls.yaml_multi_representers = cls.yaml_multi_representers.copy()
  70. cls.yaml_multi_representers[data_type] = representer
  71. add_multi_representer = classmethod(add_multi_representer)
  72. def represent_scalar(self, tag, value, style=None):
  73. if style is None:
  74. style = self.default_style
  75. node = ScalarNode(tag, value, style=style)
  76. if self.alias_key is not None:
  77. self.represented_objects[self.alias_key] = node
  78. return node
  79. def represent_sequence(self, tag, sequence, flow_style=None):
  80. value = []
  81. node = SequenceNode(tag, value, flow_style=flow_style)
  82. if self.alias_key is not None:
  83. self.represented_objects[self.alias_key] = node
  84. best_style = True
  85. for item in sequence:
  86. node_item = self.represent_data(item)
  87. if not (isinstance(node_item, ScalarNode) and not node_item.style):
  88. best_style = False
  89. value.append(node_item)
  90. if flow_style is None:
  91. if self.default_flow_style is not None:
  92. node.flow_style = self.default_flow_style
  93. else:
  94. node.flow_style = best_style
  95. return node
  96. def represent_mapping(self, tag, mapping, flow_style=None):
  97. value = []
  98. node = MappingNode(tag, value, flow_style=flow_style)
  99. if self.alias_key is not None:
  100. self.represented_objects[self.alias_key] = node
  101. best_style = True
  102. if hasattr(mapping, 'items'):
  103. mapping = mapping.items()
  104. mapping.sort()
  105. for item_key, item_value in mapping:
  106. node_key = self.represent_data(item_key)
  107. node_value = self.represent_data(item_value)
  108. if not (isinstance(node_key, ScalarNode) and not node_key.style):
  109. best_style = False
  110. if not (isinstance(node_value, ScalarNode) and not node_value.style):
  111. best_style = False
  112. value.append((node_key, node_value))
  113. if flow_style is None:
  114. if self.default_flow_style is not None:
  115. node.flow_style = self.default_flow_style
  116. else:
  117. node.flow_style = best_style
  118. return node
  119. def ignore_aliases(self, data):
  120. return False
  121. class SafeRepresenter(BaseRepresenter):
  122. def ignore_aliases(self, data):
  123. if data is None:
  124. return True
  125. if isinstance(data, tuple) and data == ():
  126. return True
  127. if isinstance(data, (str, unicode, bool, int, float)):
  128. return True
  129. def represent_none(self, data):
  130. return self.represent_scalar(u'tag:yaml.org,2002:null',
  131. u'null')
  132. def represent_str(self, data):
  133. tag = None
  134. style = None
  135. try:
  136. data = unicode(data, 'ascii')
  137. tag = u'tag:yaml.org,2002:str'
  138. except UnicodeDecodeError:
  139. try:
  140. data = unicode(data, 'utf-8')
  141. tag = u'tag:yaml.org,2002:str'
  142. except UnicodeDecodeError:
  143. data = data.encode('base64')
  144. tag = u'tag:yaml.org,2002:binary'
  145. style = '|'
  146. return self.represent_scalar(tag, data, style=style)
  147. def represent_unicode(self, data):
  148. return self.represent_scalar(u'tag:yaml.org,2002:str', data)
  149. def represent_bool(self, data):
  150. if data:
  151. value = u'true'
  152. else:
  153. value = u'false'
  154. return self.represent_scalar(u'tag:yaml.org,2002:bool', value)
  155. def represent_int(self, data):
  156. return self.represent_scalar(u'tag:yaml.org,2002:int', unicode(data))
  157. def represent_long(self, data):
  158. return self.represent_scalar(u'tag:yaml.org,2002:int', unicode(data))
  159. inf_value = 1e300
  160. while repr(inf_value) != repr(inf_value*inf_value):
  161. inf_value *= inf_value
  162. def represent_float(self, data):
  163. if data != data or (data == 0.0 and data == 1.0):
  164. value = u'.nan'
  165. elif data == self.inf_value:
  166. value = u'.inf'
  167. elif data == -self.inf_value:
  168. value = u'-.inf'
  169. else:
  170. value = unicode(repr(data)).lower()
  171. # Note that in some cases `repr(data)` represents a float number
  172. # without the decimal parts. For instance:
  173. # >>> repr(1e17)
  174. # '1e17'
  175. # Unfortunately, this is not a valid float representation according
  176. # to the definition of the `!!float` tag. We fix this by adding
  177. # '.0' before the 'e' symbol.
  178. if u'.' not in value and u'e' in value:
  179. value = value.replace(u'e', u'.0e', 1)
  180. return self.represent_scalar(u'tag:yaml.org,2002:float', value)
  181. def represent_list(self, data):
  182. #pairs = (len(data) > 0 and isinstance(data, list))
  183. #if pairs:
  184. # for item in data:
  185. # if not isinstance(item, tuple) or len(item) != 2:
  186. # pairs = False
  187. # break
  188. #if not pairs:
  189. return self.represent_sequence(u'tag:yaml.org,2002:seq', data)
  190. #value = []
  191. #for item_key, item_value in data:
  192. # value.append(self.represent_mapping(u'tag:yaml.org,2002:map',
  193. # [(item_key, item_value)]))
  194. #return SequenceNode(u'tag:yaml.org,2002:pairs', value)
  195. def represent_dict(self, data):
  196. return self.represent_mapping(u'tag:yaml.org,2002:map', data)
  197. def represent_set(self, data):
  198. value = {}
  199. for key in data:
  200. value[key] = None
  201. return self.represent_mapping(u'tag:yaml.org,2002:set', value)
  202. def represent_date(self, data):
  203. value = unicode(data.isoformat())
  204. return self.represent_scalar(u'tag:yaml.org,2002:timestamp', value)
  205. def represent_datetime(self, data):
  206. value = unicode(data.isoformat(' '))
  207. return self.represent_scalar(u'tag:yaml.org,2002:timestamp', value)
  208. def represent_yaml_object(self, tag, data, cls, flow_style=None):
  209. if hasattr(data, '__getstate__'):
  210. state = data.__getstate__()
  211. else:
  212. state = data.__dict__.copy()
  213. return self.represent_mapping(tag, state, flow_style=flow_style)
  214. def represent_undefined(self, data):
  215. raise RepresenterError("cannot represent an object: %s" % data)
  216. SafeRepresenter.add_representer(type(None),
  217. SafeRepresenter.represent_none)
  218. SafeRepresenter.add_representer(str,
  219. SafeRepresenter.represent_str)
  220. SafeRepresenter.add_representer(unicode,
  221. SafeRepresenter.represent_unicode)
  222. SafeRepresenter.add_representer(bool,
  223. SafeRepresenter.represent_bool)
  224. SafeRepresenter.add_representer(int,
  225. SafeRepresenter.represent_int)
  226. SafeRepresenter.add_representer(long,
  227. SafeRepresenter.represent_long)
  228. SafeRepresenter.add_representer(float,
  229. SafeRepresenter.represent_float)
  230. SafeRepresenter.add_representer(list,
  231. SafeRepresenter.represent_list)
  232. SafeRepresenter.add_representer(tuple,
  233. SafeRepresenter.represent_list)
  234. SafeRepresenter.add_representer(dict,
  235. SafeRepresenter.represent_dict)
  236. SafeRepresenter.add_representer(set,
  237. SafeRepresenter.represent_set)
  238. SafeRepresenter.add_representer(datetime.date,
  239. SafeRepresenter.represent_date)
  240. SafeRepresenter.add_representer(datetime.datetime,
  241. SafeRepresenter.represent_datetime)
  242. SafeRepresenter.add_representer(None,
  243. SafeRepresenter.represent_undefined)
  244. class Representer(SafeRepresenter):
  245. def represent_str(self, data):
  246. tag = None
  247. style = None
  248. try:
  249. data = unicode(data, 'ascii')
  250. tag = u'tag:yaml.org,2002:str'
  251. except UnicodeDecodeError:
  252. try:
  253. data = unicode(data, 'utf-8')
  254. tag = u'tag:yaml.org,2002:python/str'
  255. except UnicodeDecodeError:
  256. data = data.encode('base64')
  257. tag = u'tag:yaml.org,2002:binary'
  258. style = '|'
  259. return self.represent_scalar(tag, data, style=style)
  260. def represent_unicode(self, data):
  261. tag = None
  262. try:
  263. data.encode('ascii')
  264. tag = u'tag:yaml.org,2002:python/unicode'
  265. except UnicodeEncodeError:
  266. tag = u'tag:yaml.org,2002:str'
  267. return self.represent_scalar(tag, data)
  268. def represent_long(self, data):
  269. tag = u'tag:yaml.org,2002:int'
  270. if int(data) is not data:
  271. tag = u'tag:yaml.org,2002:python/long'
  272. return self.represent_scalar(tag, unicode(data))
  273. def represent_complex(self, data):
  274. if data.imag == 0.0:
  275. data = u'%r' % data.real
  276. elif data.real == 0.0:
  277. data = u'%rj' % data.imag
  278. elif data.imag > 0:
  279. data = u'%r+%rj' % (data.real, data.imag)
  280. else:
  281. data = u'%r%rj' % (data.real, data.imag)
  282. return self.represent_scalar(u'tag:yaml.org,2002:python/complex', data)
  283. def represent_tuple(self, data):
  284. return self.represent_sequence(u'tag:yaml.org,2002:python/tuple', data)
  285. def represent_name(self, data):
  286. name = u'%s.%s' % (data.__module__, data.__name__)
  287. return self.represent_scalar(u'tag:yaml.org,2002:python/name:'+name, u'')
  288. def represent_module(self, data):
  289. return self.represent_scalar(
  290. u'tag:yaml.org,2002:python/module:'+data.__name__, u'')
  291. def represent_instance(self, data):
  292. # For instances of classic classes, we use __getinitargs__ and
  293. # __getstate__ to serialize the data.
  294. # If data.__getinitargs__ exists, the object must be reconstructed by
  295. # calling cls(**args), where args is a tuple returned by
  296. # __getinitargs__. Otherwise, the cls.__init__ method should never be
  297. # called and the class instance is created by instantiating a trivial
  298. # class and assigning to the instance's __class__ variable.
  299. # If data.__getstate__ exists, it returns the state of the object.
  300. # Otherwise, the state of the object is data.__dict__.
  301. # We produce either a !!python/object or !!python/object/new node.
  302. # If data.__getinitargs__ does not exist and state is a dictionary, we
  303. # produce a !!python/object node . Otherwise we produce a
  304. # !!python/object/new node.
  305. cls = data.__class__
  306. class_name = u'%s.%s' % (cls.__module__, cls.__name__)
  307. args = None
  308. state = None
  309. if hasattr(data, '__getinitargs__'):
  310. args = list(data.__getinitargs__())
  311. if hasattr(data, '__getstate__'):
  312. state = data.__getstate__()
  313. else:
  314. state = data.__dict__
  315. if args is None and isinstance(state, dict):
  316. return self.represent_mapping(
  317. u'tag:yaml.org,2002:python/object:'+class_name, state)
  318. if isinstance(state, dict) and not state:
  319. return self.represent_sequence(
  320. u'tag:yaml.org,2002:python/object/new:'+class_name, args)
  321. value = {}
  322. if args:
  323. value['args'] = args
  324. value['state'] = state
  325. return self.represent_mapping(
  326. u'tag:yaml.org,2002:python/object/new:'+class_name, value)
  327. def represent_object(self, data):
  328. # We use __reduce__ API to save the data. data.__reduce__ returns
  329. # a tuple of length 2-5:
  330. # (function, args, state, listitems, dictitems)
  331. # For reconstructing, we calls function(*args), then set its state,
  332. # listitems, and dictitems if they are not None.
  333. # A special case is when function.__name__ == '__newobj__'. In this
  334. # case we create the object with args[0].__new__(*args).
  335. # Another special case is when __reduce__ returns a string - we don't
  336. # support it.
  337. # We produce a !!python/object, !!python/object/new or
  338. # !!python/object/apply node.
  339. cls = type(data)
  340. if cls in copy_reg.dispatch_table:
  341. reduce = copy_reg.dispatch_table[cls](data)
  342. elif hasattr(data, '__reduce_ex__'):
  343. reduce = data.__reduce_ex__(2)
  344. elif hasattr(data, '__reduce__'):
  345. reduce = data.__reduce__()
  346. else:
  347. raise RepresenterError("cannot represent object: %r" % data)
  348. reduce = (list(reduce)+[None]*5)[:5]
  349. function, args, state, listitems, dictitems = reduce
  350. args = list(args)
  351. if state is None:
  352. state = {}
  353. if listitems is not None:
  354. listitems = list(listitems)
  355. if dictitems is not None:
  356. dictitems = dict(dictitems)
  357. if function.__name__ == '__newobj__':
  358. function = args[0]
  359. args = args[1:]
  360. tag = u'tag:yaml.org,2002:python/object/new:'
  361. newobj = True
  362. else:
  363. tag = u'tag:yaml.org,2002:python/object/apply:'
  364. newobj = False
  365. function_name = u'%s.%s' % (function.__module__, function.__name__)
  366. if not args and not listitems and not dictitems \
  367. and isinstance(state, dict) and newobj:
  368. return self.represent_mapping(
  369. u'tag:yaml.org,2002:python/object:'+function_name, state)
  370. if not listitems and not dictitems \
  371. and isinstance(state, dict) and not state:
  372. return self.represent_sequence(tag+function_name, args)
  373. value = {}
  374. if args:
  375. value['args'] = args
  376. if state or not isinstance(state, dict):
  377. value['state'] = state
  378. if listitems:
  379. value['listitems'] = listitems
  380. if dictitems:
  381. value['dictitems'] = dictitems
  382. return self.represent_mapping(tag+function_name, value)
  383. Representer.add_representer(str,
  384. Representer.represent_str)
  385. Representer.add_representer(unicode,
  386. Representer.represent_unicode)
  387. Representer.add_representer(long,
  388. Representer.represent_long)
  389. Representer.add_representer(complex,
  390. Representer.represent_complex)
  391. Representer.add_representer(tuple,
  392. Representer.represent_tuple)
  393. Representer.add_representer(type,
  394. Representer.represent_name)
  395. Representer.add_representer(types.ClassType,
  396. Representer.represent_name)
  397. Representer.add_representer(types.FunctionType,
  398. Representer.represent_name)
  399. Representer.add_representer(types.BuiltinFunctionType,
  400. Representer.represent_name)
  401. Representer.add_representer(types.ModuleType,
  402. Representer.represent_module)
  403. Representer.add_multi_representer(types.InstanceType,
  404. Representer.represent_instance)
  405. Representer.add_multi_representer(object,
  406. Representer.represent_object)