1
2__all__ = ['BaseRepresenter', 'SafeRepresenter', 'Representer',
3    'RepresenterError']
4
5from error import *
6
7from nodes import *
8
9import datetime
10
11import copy_reg, types
12
13class RepresenterError(YAMLError):
14    pass
15
16class BaseRepresenter(object):
17
18    yaml_representers = {}
19    yaml_multi_representers = {}
20
21    def __init__(self, default_style=None, default_flow_style=False, sort_keys=True):
22        self.default_style = default_style
23        self.default_flow_style = default_flow_style
24        self.sort_keys = sort_keys
25        self.represented_objects = {}
26        self.object_keeper = []
27        self.alias_key = None
28
29    def represent(self, data):
30        node = self.represent_data(data)
31        self.serialize(node)
32        self.represented_objects = {}
33        self.object_keeper = []
34        self.alias_key = None
35
36    def get_classobj_bases(self, cls):
37        bases = [cls]
38        for base in cls.__bases__:
39            bases.extend(self.get_classobj_bases(base))
40        return bases
41
42    def represent_data(self, data):
43        if self.ignore_aliases(data):
44            self.alias_key = None
45        else:
46            self.alias_key = id(data)
47        if self.alias_key is not None:
48            if self.alias_key in self.represented_objects:
49                node = self.represented_objects[self.alias_key]
50                #if node is None:
51                #    raise RepresenterError("recursive objects are not allowed: %r" % data)
52                return node
53            #self.represented_objects[alias_key] = None
54            self.object_keeper.append(data)
55        data_types = type(data).__mro__
56        if type(data) is types.InstanceType:
57            data_types = self.get_classobj_bases(data.__class__)+list(data_types)
58        if data_types[0] in self.yaml_representers:
59            node = self.yaml_representers[data_types[0]](self, data)
60        else:
61            for data_type in data_types:
62                if data_type in self.yaml_multi_representers:
63                    node = self.yaml_multi_representers[data_type](self, data)
64                    break
65            else:
66                if None in self.yaml_multi_representers:
67                    node = self.yaml_multi_representers[None](self, data)
68                elif None in self.yaml_representers:
69                    node = self.yaml_representers[None](self, data)
70                else:
71                    node = ScalarNode(None, unicode(data))
72        #if alias_key is not None:
73        #    self.represented_objects[alias_key] = node
74        return node
75
76    def add_representer(cls, data_type, representer):
77        if not 'yaml_representers' in cls.__dict__:
78            cls.yaml_representers = cls.yaml_representers.copy()
79        cls.yaml_representers[data_type] = representer
80    add_representer = classmethod(add_representer)
81
82    def add_multi_representer(cls, data_type, representer):
83        if not 'yaml_multi_representers' in cls.__dict__:
84            cls.yaml_multi_representers = cls.yaml_multi_representers.copy()
85        cls.yaml_multi_representers[data_type] = representer
86    add_multi_representer = classmethod(add_multi_representer)
87
88    def represent_scalar(self, tag, value, style=None):
89        if style is None:
90            style = self.default_style
91        node = ScalarNode(tag, value, style=style)
92        if self.alias_key is not None:
93            self.represented_objects[self.alias_key] = node
94        return node
95
96    def represent_sequence(self, tag, sequence, flow_style=None):
97        value = []
98        node = SequenceNode(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        for item in sequence:
103            node_item = self.represent_data(item)
104            if not (isinstance(node_item, ScalarNode) and not node_item.style):
105                best_style = False
106            value.append(node_item)
107        if flow_style is None:
108            if self.default_flow_style is not None:
109                node.flow_style = self.default_flow_style
110            else:
111                node.flow_style = best_style
112        return node
113
114    def represent_mapping(self, tag, mapping, flow_style=None):
115        value = []
116        node = MappingNode(tag, value, flow_style=flow_style)
117        if self.alias_key is not None:
118            self.represented_objects[self.alias_key] = node
119        best_style = True
120        if hasattr(mapping, 'items'):
121            mapping = mapping.items()
122            if self.sort_keys:
123                mapping.sort()
124        for item_key, item_value in mapping:
125            node_key = self.represent_data(item_key)
126            node_value = self.represent_data(item_value)
127            if not (isinstance(node_key, ScalarNode) and not node_key.style):
128                best_style = False
129            if not (isinstance(node_value, ScalarNode) and not node_value.style):
130                best_style = False
131            value.append((node_key, node_value))
132        if flow_style is None:
133            if self.default_flow_style is not None:
134                node.flow_style = self.default_flow_style
135            else:
136                node.flow_style = best_style
137        return node
138
139    def ignore_aliases(self, data):
140        return False
141
142class SafeRepresenter(BaseRepresenter):
143
144    def ignore_aliases(self, data):
145        if data is None:
146            return True
147        if isinstance(data, tuple) and data == ():
148            return True
149        if isinstance(data, (str, unicode, bool, int, float)):
150            return True
151
152    def represent_none(self, data):
153        return self.represent_scalar(u'tag:yaml.org,2002:null',
154                u'null')
155
156    def represent_str(self, data):
157        tag = None
158        style = None
159        try:
160            data = unicode(data, 'ascii')
161            tag = u'tag:yaml.org,2002:str'
162        except UnicodeDecodeError:
163            try:
164                data = unicode(data, 'utf-8')
165                tag = u'tag:yaml.org,2002:str'
166            except UnicodeDecodeError:
167                data = data.encode('base64')
168                tag = u'tag:yaml.org,2002:binary'
169                style = '|'
170        return self.represent_scalar(tag, data, style=style)
171
172    def represent_unicode(self, data):
173        return self.represent_scalar(u'tag:yaml.org,2002:str', data)
174
175    def represent_bool(self, data):
176        if data:
177            value = u'true'
178        else:
179            value = u'false'
180        return self.represent_scalar(u'tag:yaml.org,2002:bool', value)
181
182    def represent_int(self, data):
183        return self.represent_scalar(u'tag:yaml.org,2002:int', unicode(data))
184
185    def represent_long(self, data):
186        return self.represent_scalar(u'tag:yaml.org,2002:int', unicode(data))
187
188    inf_value = 1e300
189    while repr(inf_value) != repr(inf_value*inf_value):
190        inf_value *= inf_value
191
192    def represent_float(self, data):
193        if data != data or (data == 0.0 and data == 1.0):
194            value = u'.nan'
195        elif data == self.inf_value:
196            value = u'.inf'
197        elif data == -self.inf_value:
198            value = u'-.inf'
199        else:
200            value = unicode(repr(data)).lower()
201            # Note that in some cases `repr(data)` represents a float number
202            # without the decimal parts.  For instance:
203            #   >>> repr(1e17)
204            #   '1e17'
205            # Unfortunately, this is not a valid float representation according
206            # to the definition of the `!!float` tag.  We fix this by adding
207            # '.0' before the 'e' symbol.
208            if u'.' not in value and u'e' in value:
209                value = value.replace(u'e', u'.0e', 1)
210        return self.represent_scalar(u'tag:yaml.org,2002:float', value)
211
212    def represent_list(self, data):
213        #pairs = (len(data) > 0 and isinstance(data, list))
214        #if pairs:
215        #    for item in data:
216        #        if not isinstance(item, tuple) or len(item) != 2:
217        #            pairs = False
218        #            break
219        #if not pairs:
220            return self.represent_sequence(u'tag:yaml.org,2002:seq', data)
221        #value = []
222        #for item_key, item_value in data:
223        #    value.append(self.represent_mapping(u'tag:yaml.org,2002:map',
224        #        [(item_key, item_value)]))
225        #return SequenceNode(u'tag:yaml.org,2002:pairs', value)
226
227    def represent_dict(self, data):
228        return self.represent_mapping(u'tag:yaml.org,2002:map', data)
229
230    def represent_set(self, data):
231        value = {}
232        for key in data:
233            value[key] = None
234        return self.represent_mapping(u'tag:yaml.org,2002:set', value)
235
236    def represent_date(self, data):
237        value = unicode(data.isoformat())
238        return self.represent_scalar(u'tag:yaml.org,2002:timestamp', value)
239
240    def represent_datetime(self, data):
241        value = unicode(data.isoformat(' '))
242        return self.represent_scalar(u'tag:yaml.org,2002:timestamp', value)
243
244    def represent_yaml_object(self, tag, data, cls, flow_style=None):
245        if hasattr(data, '__getstate__'):
246            state = data.__getstate__()
247        else:
248            state = data.__dict__.copy()
249        return self.represent_mapping(tag, state, flow_style=flow_style)
250
251    def represent_undefined(self, data):
252        raise RepresenterError("cannot represent an object", data)
253
254SafeRepresenter.add_representer(type(None),
255        SafeRepresenter.represent_none)
256
257SafeRepresenter.add_representer(str,
258        SafeRepresenter.represent_str)
259
260SafeRepresenter.add_representer(unicode,
261        SafeRepresenter.represent_unicode)
262
263SafeRepresenter.add_representer(bool,
264        SafeRepresenter.represent_bool)
265
266SafeRepresenter.add_representer(int,
267        SafeRepresenter.represent_int)
268
269SafeRepresenter.add_representer(long,
270        SafeRepresenter.represent_long)
271
272SafeRepresenter.add_representer(float,
273        SafeRepresenter.represent_float)
274
275SafeRepresenter.add_representer(list,
276        SafeRepresenter.represent_list)
277
278SafeRepresenter.add_representer(tuple,
279        SafeRepresenter.represent_list)
280
281SafeRepresenter.add_representer(dict,
282        SafeRepresenter.represent_dict)
283
284SafeRepresenter.add_representer(set,
285        SafeRepresenter.represent_set)
286
287SafeRepresenter.add_representer(datetime.date,
288        SafeRepresenter.represent_date)
289
290SafeRepresenter.add_representer(datetime.datetime,
291        SafeRepresenter.represent_datetime)
292
293SafeRepresenter.add_representer(None,
294        SafeRepresenter.represent_undefined)
295
296class Representer(SafeRepresenter):
297
298    def represent_str(self, data):
299        tag = None
300        style = None
301        try:
302            data = unicode(data, 'ascii')
303            tag = u'tag:yaml.org,2002:str'
304        except UnicodeDecodeError:
305            try:
306                data = unicode(data, 'utf-8')
307                tag = u'tag:yaml.org,2002:python/str'
308            except UnicodeDecodeError:
309                data = data.encode('base64')
310                tag = u'tag:yaml.org,2002:binary'
311                style = '|'
312        return self.represent_scalar(tag, data, style=style)
313
314    def represent_unicode(self, data):
315        tag = None
316        try:
317            data.encode('ascii')
318            tag = u'tag:yaml.org,2002:python/unicode'
319        except UnicodeEncodeError:
320            tag = u'tag:yaml.org,2002:str'
321        return self.represent_scalar(tag, data)
322
323    def represent_long(self, data):
324        tag = u'tag:yaml.org,2002:int'
325        if int(data) is not data:
326            tag = u'tag:yaml.org,2002:python/long'
327        return self.represent_scalar(tag, unicode(data))
328
329    def represent_complex(self, data):
330        if data.imag == 0.0:
331            data = u'%r' % data.real
332        elif data.real == 0.0:
333            data = u'%rj' % data.imag
334        elif data.imag > 0:
335            data = u'%r+%rj' % (data.real, data.imag)
336        else:
337            data = u'%r%rj' % (data.real, data.imag)
338        return self.represent_scalar(u'tag:yaml.org,2002:python/complex', data)
339
340    def represent_tuple(self, data):
341        return self.represent_sequence(u'tag:yaml.org,2002:python/tuple', data)
342
343    def represent_name(self, data):
344        name = u'%s.%s' % (data.__module__, data.__name__)
345        return self.represent_scalar(u'tag:yaml.org,2002:python/name:'+name, u'')
346
347    def represent_module(self, data):
348        return self.represent_scalar(
349                u'tag:yaml.org,2002:python/module:'+data.__name__, u'')
350
351    def represent_instance(self, data):
352        # For instances of classic classes, we use __getinitargs__ and
353        # __getstate__ to serialize the data.
354
355        # If data.__getinitargs__ exists, the object must be reconstructed by
356        # calling cls(**args), where args is a tuple returned by
357        # __getinitargs__. Otherwise, the cls.__init__ method should never be
358        # called and the class instance is created by instantiating a trivial
359        # class and assigning to the instance's __class__ variable.
360
361        # If data.__getstate__ exists, it returns the state of the object.
362        # Otherwise, the state of the object is data.__dict__.
363
364        # We produce either a !!python/object or !!python/object/new node.
365        # If data.__getinitargs__ does not exist and state is a dictionary, we
366        # produce a !!python/object node . Otherwise we produce a
367        # !!python/object/new node.
368
369        cls = data.__class__
370        class_name = u'%s.%s' % (cls.__module__, cls.__name__)
371        args = None
372        state = None
373        if hasattr(data, '__getinitargs__'):
374            args = list(data.__getinitargs__())
375        if hasattr(data, '__getstate__'):
376            state = data.__getstate__()
377        else:
378            state = data.__dict__
379        if args is None and isinstance(state, dict):
380            return self.represent_mapping(
381                    u'tag:yaml.org,2002:python/object:'+class_name, state)
382        if isinstance(state, dict) and not state:
383            return self.represent_sequence(
384                    u'tag:yaml.org,2002:python/object/new:'+class_name, args)
385        value = {}
386        if args:
387            value['args'] = args
388        value['state'] = state
389        return self.represent_mapping(
390                u'tag:yaml.org,2002:python/object/new:'+class_name, value)
391
392    def represent_object(self, data):
393        # We use __reduce__ API to save the data. data.__reduce__ returns
394        # a tuple of length 2-5:
395        #   (function, args, state, listitems, dictitems)
396
397        # For reconstructing, we calls function(*args), then set its state,
398        # listitems, and dictitems if they are not None.
399
400        # A special case is when function.__name__ == '__newobj__'. In this
401        # case we create the object with args[0].__new__(*args).
402
403        # Another special case is when __reduce__ returns a string - we don't
404        # support it.
405
406        # We produce a !!python/object, !!python/object/new or
407        # !!python/object/apply node.
408
409        cls = type(data)
410        if cls in copy_reg.dispatch_table:
411            reduce = copy_reg.dispatch_table[cls](data)
412        elif hasattr(data, '__reduce_ex__'):
413            reduce = data.__reduce_ex__(2)
414        elif hasattr(data, '__reduce__'):
415            reduce = data.__reduce__()
416        else:
417            raise RepresenterError("cannot represent an object", data)
418        reduce = (list(reduce)+[None]*5)[:5]
419        function, args, state, listitems, dictitems = reduce
420        args = list(args)
421        if state is None:
422            state = {}
423        if listitems is not None:
424            listitems = list(listitems)
425        if dictitems is not None:
426            dictitems = dict(dictitems)
427        if function.__name__ == '__newobj__':
428            function = args[0]
429            args = args[1:]
430            tag = u'tag:yaml.org,2002:python/object/new:'
431            newobj = True
432        else:
433            tag = u'tag:yaml.org,2002:python/object/apply:'
434            newobj = False
435        function_name = u'%s.%s' % (function.__module__, function.__name__)
436        if not args and not listitems and not dictitems \
437                and isinstance(state, dict) and newobj:
438            return self.represent_mapping(
439                    u'tag:yaml.org,2002:python/object:'+function_name, state)
440        if not listitems and not dictitems  \
441                and isinstance(state, dict) and not state:
442            return self.represent_sequence(tag+function_name, args)
443        value = {}
444        if args:
445            value['args'] = args
446        if state or not isinstance(state, dict):
447            value['state'] = state
448        if listitems:
449            value['listitems'] = listitems
450        if dictitems:
451            value['dictitems'] = dictitems
452        return self.represent_mapping(tag+function_name, value)
453
454Representer.add_representer(str,
455        Representer.represent_str)
456
457Representer.add_representer(unicode,
458        Representer.represent_unicode)
459
460Representer.add_representer(long,
461        Representer.represent_long)
462
463Representer.add_representer(complex,
464        Representer.represent_complex)
465
466Representer.add_representer(tuple,
467        Representer.represent_tuple)
468
469Representer.add_representer(type,
470        Representer.represent_name)
471
472Representer.add_representer(types.ClassType,
473        Representer.represent_name)
474
475Representer.add_representer(types.FunctionType,
476        Representer.represent_name)
477
478Representer.add_representer(types.BuiltinFunctionType,
479        Representer.represent_name)
480
481Representer.add_representer(types.ModuleType,
482        Representer.represent_module)
483
484Representer.add_multi_representer(types.InstanceType,
485        Representer.represent_instance)
486
487Representer.add_multi_representer(object,
488        Representer.represent_object)
489
490