lib/yaml/representer.py

   1
   2 __all__ = ['BaseRepresenter', 'SafeRepresenter', 'Representer',
   3     'RepresenterError']
   4
   5 from error import *
   6 from nodes import *
   7
   8 try:
   9     import datetime
  10     datetime_available = True
  11 except ImportError:
  12     datetime_available = False
  13
  14 try:
  15     set
  16 except NameError:
  17     from sets import Set as set
  18
  19 import sys, copy_reg
  20
  21 class RepresenterError(YAMLError):
  22     pass
  23
  24 class BaseRepresenter(object):
  25
  26     yaml_representers = {}
  27     yaml_multi_representers = {}
  28
  29     def __init__(self, default_style=None, default_flow_style=None):
  30         self.default_style = default_style
  31         self.default_flow_style = default_flow_style
  32         self.represented_objects = {}
  33         self.object_keeper = []
  34         self.alias_key = None
  35
  36     def represent(self, data):
  37         node = self.represent_data(data)
  38         self.serialize(node)
  39         self.represented_objects = {}
  40         self.object_keeper = []
  41         self.alias_key = None
  42
  43     class C: pass
  44     c = C()
  45     def f(): pass
  46     def g(): yield None
  47     classobj_type = type(C)
  48     instance_type = type(c)
  49     function_type = type(f)
  50     generator_type = type(g())
  51     builtin_function_type = type(abs)
  52     module_type = type(sys)
  53     del C, c, f, g
  54
  55     def get_classobj_bases(self, cls):
  56         bases = [cls]
  57         for base in cls.__bases__:
  58             bases.extend(self.get_classobj_bases(base))
  59         return bases
  60
  61     def represent_data(self, data):
  62         if self.ignore_aliases(data):
  63             self.alias_key = None
  64         else:
  65             self.alias_key = id(data)
  66         if self.alias_key is not None:
  67             if self.alias_key in self.represented_objects:
  68                 node = self.represented_objects[self.alias_key]
  69                 #if node is None:
  70                 #    raise RepresenterError("recursive objects are not allowed: %r" % data)
  71                 return node
  72             #self.represented_objects[alias_key] = None
  73             self.object_keeper.append(data)
  74         data_types = type(data).__mro__
  75         if type(data) is self.instance_type:
  76             data_types = self.get_classobj_bases(data.__class__)+list(data_types)
  77         if data_types[0] in self.yaml_representers:
  78             node = self.yaml_representers[data_types[0]](self, data)
  79         else:
  80             for data_type in data_types:
  81                 if data_type in self.yaml_multi_representers:
  82                     node = self.yaml_multi_representers[data_type](self, data)
  83                     break
  84             else:
  85                 if None in self.yaml_multi_representers:
  86                     node = self.yaml_multi_representers[None](self, data)
  87                 elif None in self.yaml_representers:
  88                     node = self.yaml_representers[None](self, data)
  89                 else:
  90                     node = ScalarNode(None, unicode(data))
  91         #if alias_key is not None:
  92         #    self.represented_objects[alias_key] = node
  93         return node
  94
  95     def add_representer(cls, data_type, representer):
  96         if not 'yaml_representers' in cls.__dict__:
  97             cls.yaml_representers = cls.yaml_representers.copy()
  98         cls.yaml_representers[data_type] = representer
  99     add_representer = classmethod(add_representer)
 100
 101     def add_multi_representer(cls, data_type, representer):
 102         if not 'yaml_multi_representers' in cls.__dict__:
 103             cls.yaml_multi_representers = cls.yaml_multi_representers.copy()
 104         cls.yaml_multi_representers[data_type] = representer
 105     add_multi_representer = classmethod(add_multi_representer)
 106
 107     def represent_scalar(self, tag, value, style=None):
 108         if style is None:
 109             style = self.default_style
 110         node = ScalarNode(tag, value, style=style)
 111         if self.alias_key is not None:
 112             self.represented_objects[self.alias_key] = node
 113         return node
 114
 115     def represent_sequence(self, tag, sequence, flow_style=None):
 116         value = []
 117         node = SequenceNode(tag, value, flow_style=flow_style)
 118         if self.alias_key is not None:
 119             self.represented_objects[self.alias_key] = node
 120         best_style = True
 121         for item in sequence:
 122             node_item = self.represent_data(item)
 123             if not (isinstance(node_item, ScalarNode) and not node_item.style):
 124                 best_style = False
 125             value.append(node_item)
 126         if flow_style is None:
 127             if self.default_flow_style is not None:
 128                 node.flow_style = self.default_flow_style
 129             else:
 130                 node.flow_style = best_style
 131         return node
 132
 133     def represent_mapping(self, tag, mapping, flow_style=None):
 134         value = []
 135         node = MappingNode(tag, value, flow_style=flow_style)
 136         if self.alias_key is not None:
 137             self.represented_objects[self.alias_key] = node
 138         best_style = True
 139         if hasattr(mapping, 'items'):
 140             mapping = mapping.items()
 141             mapping.sort()
 142         for item_key, item_value in mapping:
 143             node_key = self.represent_data(item_key)
 144             node_value = self.represent_data(item_value)
 145             if not (isinstance(node_key, ScalarNode) and not node_key.style):
 146                 best_style = False
 147             if not (isinstance(node_value, ScalarNode) and not node_value.style):
 148                 best_style = False
 149             value.append((node_key, node_value))
 150         if flow_style is None:
 151             if self.default_flow_style is not None:
 152                 node.flow_style = self.default_flow_style
 153             else:
 154                 node.flow_style = best_style
 155         return node
 156
 157     def ignore_aliases(self, data):
 158         return False
 159
 160 class SafeRepresenter(BaseRepresenter):
 161
 162     def ignore_aliases(self, data):
 163         if data in [None, ()]:
 164             return True
 165         if isinstance(data, (str, unicode, bool, int, float)):
 166             return True
 167
 168     def represent_none(self, data):
 169         return self.represent_scalar(u'tag:yaml.org,2002:null',
 170                 u'null')
 171
 172     def represent_str(self, data):
 173         tag = None
 174         style = None
 175         try:
 176             data = unicode(data, 'ascii')
 177             tag = u'tag:yaml.org,2002:str'
 178         except UnicodeDecodeError:
 179             try:
 180                 data = unicode(data, 'utf-8')
 181                 tag = u'tag:yaml.org,2002:str'
 182             except UnicodeDecodeError:
 183                 data = data.encode('base64')
 184                 tag = u'tag:yaml.org,2002:binary'
 185                 style = '|'
 186         return self.represent_scalar(tag, data, style=style)
 187
 188     def represent_unicode(self, data):
 189         return self.represent_scalar(u'tag:yaml.org,2002:str', data)
 190
 191     def represent_bool(self, data):
 192         if data:
 193             value = u'true'
 194         else:
 195             value = u'false'
 196         return self.represent_scalar(u'tag:yaml.org,2002:bool', value)
 197
 198     def represent_int(self, data):
 199         return self.represent_scalar(u'tag:yaml.org,2002:int', unicode(data))
 200
 201     def represent_long(self, data):
 202         return self.represent_scalar(u'tag:yaml.org,2002:int', unicode(data))
 203
 204     inf_value = 1e300
 205     while repr(inf_value) != repr(inf_value*inf_value):
 206         inf_value *= inf_value
 207
 208     def represent_float(self, data):
 209         if data != data or (data == 0.0 and data == 1.0):
 210             value = u'.nan'
 211         elif data == self.inf_value:
 212             value = u'.inf'
 213         elif data == -self.inf_value:
 214             value = u'-.inf'
 215         else:
 216             value = unicode(repr(data))
 217         return self.represent_scalar(u'tag:yaml.org,2002:float', value)
 218
 219     def represent_list(self, data):
 220         #pairs = (len(data) > 0 and isinstance(data, list))
 221         #if pairs:
 222         #    for item in data:
 223         #        if not isinstance(item, tuple) or len(item) != 2:
 224         #            pairs = False
 225         #            break
 226         #if not pairs:
 227             return self.represent_sequence(u'tag:yaml.org,2002:seq', data)
 228         #value = []
 229         #for item_key, item_value in data:
 230         #    value.append(self.represent_mapping(u'tag:yaml.org,2002:map',
 231         #        [(item_key, item_value)]))
 232         #return SequenceNode(u'tag:yaml.org,2002:pairs', value)
 233
 234     def represent_dict(self, data):
 235         return self.represent_mapping(u'tag:yaml.org,2002:map', data)
 236
 237     def represent_set(self, data):
 238         value = {}
 239         for key in data:
 240             value[key] = None
 241         return self.represent_mapping(u'tag:yaml.org,2002:set', value)
 242
 243     def represent_date(self, data):
 244         value = u'%04d-%02d-%02d' % (data.year, data.month, data.day)
 245         return self.represent_scalar(u'tag:yaml.org,2002:timestamp', value)
 246
 247     def represent_datetime(self, data):
 248         value = u'%04d-%02d-%02d %02d:%02d:%02d' \
 249                 % (data.year, data.month, data.day,
 250                     data.hour, data.minute, data.second)
 251         if data.microsecond:
 252             value += u'.' + unicode(data.microsecond/1000000.0).split(u'.')[1]
 253         if data.utcoffset():
 254             value += unicode(data.utcoffset())
 255         return self.represent_scalar(u'tag:yaml.org,2002:timestamp', value)
 256
 257     def represent_yaml_object(self, tag, data, cls, flow_style=None):
 258         if hasattr(data, '__getstate__'):
 259             state = data.__getstate__()
 260         else:
 261             state = data.__dict__.copy()
 262         return self.represent_mapping(tag, state, flow_style=flow_style)
 263
 264     def represent_undefined(self, data):
 265         raise RepresenterError("cannot represent an object: %s" % data)
 266
 267 SafeRepresenter.add_representer(type(None),
 268         SafeRepresenter.represent_none)
 269
 270 SafeRepresenter.add_representer(str,
 271         SafeRepresenter.represent_str)
 272
 273 SafeRepresenter.add_representer(unicode,
 274         SafeRepresenter.represent_unicode)
 275
 276 SafeRepresenter.add_representer(bool,
 277         SafeRepresenter.represent_bool)
 278
 279 SafeRepresenter.add_representer(int,
 280         SafeRepresenter.represent_int)
 281
 282 SafeRepresenter.add_representer(long,
 283         SafeRepresenter.represent_long)
 284
 285 SafeRepresenter.add_representer(float,
 286         SafeRepresenter.represent_float)
 287
 288 SafeRepresenter.add_representer(list,
 289         SafeRepresenter.represent_list)
 290
 291 SafeRepresenter.add_representer(tuple,
 292         SafeRepresenter.represent_list)
 293
 294 SafeRepresenter.add_representer(dict,
 295         SafeRepresenter.represent_dict)
 296
 297 SafeRepresenter.add_representer(set,
 298         SafeRepresenter.represent_set)
 299
 300 if datetime_available:
 301     SafeRepresenter.add_representer(datetime.date,
 302             SafeRepresenter.represent_date)
 303     SafeRepresenter.add_representer(datetime.datetime,
 304             SafeRepresenter.represent_datetime)
 305
 306 SafeRepresenter.add_representer(None,
 307         SafeRepresenter.represent_undefined)
 308
 309 class Representer(SafeRepresenter):
 310
 311     def represent_str(self, data):
 312         tag = None
 313         style = None
 314         try:
 315             data = unicode(data, 'ascii')
 316             tag = u'tag:yaml.org,2002:str'
 317         except UnicodeDecodeError:
 318             try:
 319                 data = unicode(data, 'utf-8')
 320                 tag = u'tag:yaml.org,2002:python/str'
 321             except UnicodeDecodeError:
 322                 data = data.encode('base64')
 323                 tag = u'tag:yaml.org,2002:binary'
 324                 style = '|'
 325         return self.represent_scalar(tag, data, style=style)
 326
 327     def represent_unicode(self, data):
 328         tag = None
 329         try:
 330             data.encode('ascii')
 331             tag = u'tag:yaml.org,2002:python/unicode'
 332         except UnicodeEncodeError:
 333             tag = u'tag:yaml.org,2002:str'
 334         return self.represent_scalar(tag, data)
 335
 336     def represent_long(self, data):
 337         tag = u'tag:yaml.org,2002:int'
 338         if int(data) is not data:
 339             tag = u'tag:yaml.org,2002:python/long'
 340         return self.represent_scalar(tag, unicode(data))
 341
 342     def represent_complex(self, data):
 343         if data.imag == 0.0:
 344             data = u'%r' % data.real
 345         elif data.real == 0.0:
 346             data = u'%rj' % data.imag
 347         elif data.imag > 0:
 348             data = u'%r+%rj' % (data.real, data.imag)
 349         else:
 350             data = u'%r%rj' % (data.real, data.imag)
 351         return self.represent_scalar(u'tag:yaml.org,2002:python/complex', data)
 352
 353     def represent_tuple(self, data):
 354         return self.represent_sequence(u'tag:yaml.org,2002:python/tuple', data)
 355
 356     def represent_name(self, data):
 357         name = u'%s.%s' % (data.__module__, data.__name__)
 358         return self.represent_scalar(u'tag:yaml.org,2002:python/name:'+name, u'')
 359
 360     def represent_module(self, data):
 361         return self.represent_scalar(
 362                 u'tag:yaml.org,2002:python/module:'+data.__name__, u'')
 363
 364     def represent_instance(self, data):
 365         # For instances of classic classes, we use __getinitargs__ and
 366         # __getstate__ to serialize the data.
 367
 368         # If data.__getinitargs__ exists, the object must be reconstructed by
 369         # calling cls(**args), where args is a tuple returned by
 370         # __getinitargs__. Otherwise, the cls.__init__ method should never be
 371         # called and the class instance is created by instantiating a trivial
 372         # class and assigning to the instance's __class__ variable.
 373
 374         # If data.__getstate__ exists, it returns the state of the object.
 375         # Otherwise, the state of the object is data.__dict__.
 376
 377         # We produce either a !!python/object or !!python/object/new node.
 378         # If data.__getinitargs__ does not exist and state is a dictionary, we
 379         # produce a !!python/object node . Otherwise we produce a
 380         # !!python/object/new node.
 381
 382         cls = data.__class__
 383         class_name = u'%s.%s' % (cls.__module__, cls.__name__)
 384         args = None
 385         state = None
 386         if hasattr(data, '__getinitargs__'):
 387             args = list(data.__getinitargs__())
 388         if hasattr(data, '__getstate__'):
 389             state = data.__getstate__()
 390         else:
 391             state = data.__dict__
 392         if args is None and isinstance(state, dict):
 393             return self.represent_mapping(
 394                     u'tag:yaml.org,2002:python/object:'+class_name, state)
 395         if isinstance(state, dict) and not state:
 396             return self.represent_sequence(
 397                     u'tag:yaml.org,2002:python/object/new:'+class_name, args)
 398         value = {}
 399         if args:
 400             value['args'] = args
 401         value['state'] = state
 402         return self.represent_mapping(
 403                 u'tag:yaml.org,2002:python/object/new:'+class_name, value)
 404
 405     def represent_object(self, data):
 406         # We use __reduce__ API to save the data. data.__reduce__ returns
 407         # a tuple of length 2-5:
 408         #   (function, args, state, listitems, dictitems)
 409
 410         # For reconstructing, we calls function(*args), then set its state,
 411         # listitems, and dictitems if they are not None.
 412
 413         # A special case is when function.__name__ == '__newobj__'. In this
 414         # case we create the object with args[0].__new__(*args).
 415
 416         # Another special case is when __reduce__ returns a string - we don't
 417         # support it.
 418
 419         # We produce a !!python/object, !!python/object/new or
 420         # !!python/object/apply node.
 421
 422         cls = type(data)
 423         if cls in copy_reg.dispatch_table:
 424             reduce = copy_reg.dispatch_table[cls](data)
 425         elif hasattr(data, '__reduce_ex__'):
 426             reduce = data.__reduce_ex__(2)
 427         elif hasattr(data, '__reduce__'):
 428             reduce = data.__reduce__()
 429         else:
 430             raise RepresenterError("cannot represent object: %r" % data)
 431         reduce = (list(reduce)+[None]*5)[:5]
 432         function, args, state, listitems, dictitems = reduce
 433         args = list(args)
 434         if state is None:
 435             state = {}
 436         if listitems is not None:
 437             listitems = list(listitems)
 438         if dictitems is not None:
 439             dictitems = dict(dictitems)
 440         if function.__name__ == '__newobj__':
 441             function = args[0]
 442             args = args[1:]
 443             tag = u'tag:yaml.org,2002:python/object/new:'
 444             newobj = True
 445         else:
 446             tag = u'tag:yaml.org,2002:python/object/apply:'
 447             newobj = False
 448         function_name = u'%s.%s' % (function.__module__, function.__name__)
 449         if not args and not listitems and not dictitems \
 450                 and isinstance(state, dict) and newobj:
 451             return self.represent_mapping(
 452                     u'tag:yaml.org,2002:python/object:'+function_name, state)
 453         if not listitems and not dictitems  \
 454                 and isinstance(state, dict) and not state:
 455             return self.represent_sequence(tag+function_name, args)
 456         value = {}
 457         if args:
 458             value['args'] = args
 459         if state or not isinstance(state, dict):
 460             value['state'] = state
 461         if listitems:
 462             value['listitems'] = listitems
 463         if dictitems:
 464             value['dictitems'] = dictitems
 465         return self.represent_mapping(tag+function_name, value)
 466
 467 Representer.add_representer(str,
 468         Representer.represent_str)
 469
 470 Representer.add_representer(unicode,
 471         Representer.represent_unicode)
 472
 473 Representer.add_representer(long,
 474         Representer.represent_long)
 475
 476 Representer.add_representer(complex,
 477         Representer.represent_complex)
 478
 479 Representer.add_representer(tuple,
 480         Representer.represent_tuple)
 481
 482 Representer.add_representer(type,
 483         Representer.represent_name)
 484
 485 Representer.add_representer(Representer.classobj_type,
 486         Representer.represent_name)
 487
 488 Representer.add_representer(Representer.function_type,
 489         Representer.represent_name)
 490
 491 Representer.add_representer(Representer.builtin_function_type,
 492         Representer.represent_name)
 493
 494 Representer.add_representer(Representer.module_type,
 495         Representer.represent_module)
 496
 497 Representer.add_multi_representer(Representer.instance_type,
 498         Representer.represent_instance)
 499
 500 Representer.add_multi_representer(object,
 501         Representer.represent_object)
 502