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