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__all__ = ['BaseRepresenter', 'SafeRepresenter', 'Representer', | |
'RepresenterError'] | |
from .error import * | |
from .nodes import * | |
import datetime, copyreg, types, base64, collections | |
class RepresenterError(YAMLError): | |
pass | |
class BaseRepresenter: | |
yaml_representers = {} | |
yaml_multi_representers = {} | |
def __init__(self, default_style=None, default_flow_style=False, sort_keys=True): | |
self.default_style = default_style | |
self.sort_keys = sort_keys | |
self.default_flow_style = default_flow_style | |
self.represented_objects = {} | |
self.object_keeper = [] | |
self.alias_key = None | |
def represent(self, data): | |
node = self.represent_data(data) | |
self.serialize(node) | |
self.represented_objects = {} | |
self.object_keeper = [] | |
self.alias_key = None | |
def represent_data(self, data): | |
if self.ignore_aliases(data): | |
self.alias_key = None | |
else: | |
self.alias_key = id(data) | |
if self.alias_key is not None: | |
if self.alias_key in self.represented_objects: | |
node = self.represented_objects[self.alias_key] | |
#if node is None: | |
# raise RepresenterError("recursive objects are not allowed: %r" % data) | |
return node | |
#self.represented_objects[alias_key] = None | |
self.object_keeper.append(data) | |
data_types = type(data).__mro__ | |
if data_types[0] in self.yaml_representers: | |
node = self.yaml_representers[data_types[0]](self, data) | |
else: | |
for data_type in data_types: | |
if data_type in self.yaml_multi_representers: | |
node = self.yaml_multi_representers[data_type](self, data) | |
break | |
else: | |
if None in self.yaml_multi_representers: | |
node = self.yaml_multi_representers[None](self, data) | |
elif None in self.yaml_representers: | |
node = self.yaml_representers[None](self, data) | |
else: | |
node = ScalarNode(None, str(data)) | |
#if alias_key is not None: | |
# self.represented_objects[alias_key] = node | |
return node | |
def add_representer(cls, data_type, representer): | |
if not 'yaml_representers' in cls.__dict__: | |
cls.yaml_representers = cls.yaml_representers.copy() | |
cls.yaml_representers[data_type] = representer | |
def add_multi_representer(cls, data_type, representer): | |
if not 'yaml_multi_representers' in cls.__dict__: | |
cls.yaml_multi_representers = cls.yaml_multi_representers.copy() | |
cls.yaml_multi_representers[data_type] = representer | |
def represent_scalar(self, tag, value, style=None): | |
if style is None: | |
style = self.default_style | |
node = ScalarNode(tag, value, style=style) | |
if self.alias_key is not None: | |
self.represented_objects[self.alias_key] = node | |
return node | |
def represent_sequence(self, tag, sequence, flow_style=None): | |
value = [] | |
node = SequenceNode(tag, value, flow_style=flow_style) | |
if self.alias_key is not None: | |
self.represented_objects[self.alias_key] = node | |
best_style = True | |
for item in sequence: | |
node_item = self.represent_data(item) | |
if not (isinstance(node_item, ScalarNode) and not node_item.style): | |
best_style = False | |
value.append(node_item) | |
if flow_style is None: | |
if self.default_flow_style is not None: | |
node.flow_style = self.default_flow_style | |
else: | |
node.flow_style = best_style | |
return node | |
def represent_mapping(self, tag, mapping, flow_style=None): | |
value = [] | |
node = MappingNode(tag, value, flow_style=flow_style) | |
if self.alias_key is not None: | |
self.represented_objects[self.alias_key] = node | |
best_style = True | |
if hasattr(mapping, 'items'): | |
mapping = list(mapping.items()) | |
if self.sort_keys: | |
try: | |
mapping = sorted(mapping) | |
except TypeError: | |
pass | |
for item_key, item_value in mapping: | |
node_key = self.represent_data(item_key) | |
node_value = self.represent_data(item_value) | |
if not (isinstance(node_key, ScalarNode) and not node_key.style): | |
best_style = False | |
if not (isinstance(node_value, ScalarNode) and not node_value.style): | |
best_style = False | |
value.append((node_key, node_value)) | |
if flow_style is None: | |
if self.default_flow_style is not None: | |
node.flow_style = self.default_flow_style | |
else: | |
node.flow_style = best_style | |
return node | |
def ignore_aliases(self, data): | |
return False | |
class SafeRepresenter(BaseRepresenter): | |
def ignore_aliases(self, data): | |
if data is None: | |
return True | |
if isinstance(data, tuple) and data == (): | |
return True | |
if isinstance(data, (str, bytes, bool, int, float)): | |
return True | |
def represent_none(self, data): | |
return self.represent_scalar('tag:yaml.org,2002:null', 'null') | |
def represent_str(self, data): | |
return self.represent_scalar('tag:yaml.org,2002:str', data) | |
def represent_binary(self, data): | |
if hasattr(base64, 'encodebytes'): | |
data = base64.encodebytes(data).decode('ascii') | |
else: | |
data = base64.encodestring(data).decode('ascii') | |
return self.represent_scalar('tag:yaml.org,2002:binary', data, style='|') | |
def represent_bool(self, data): | |
if data: | |
value = 'true' | |
else: | |
value = 'false' | |
return self.represent_scalar('tag:yaml.org,2002:bool', value) | |
def represent_int(self, data): | |
return self.represent_scalar('tag:yaml.org,2002:int', str(data)) | |
inf_value = 1e300 | |
while repr(inf_value) != repr(inf_value*inf_value): | |
inf_value *= inf_value | |
def represent_float(self, data): | |
if data != data or (data == 0.0 and data == 1.0): | |
value = '.nan' | |
elif data == self.inf_value: | |
value = '.inf' | |
elif data == -self.inf_value: | |
value = '-.inf' | |
else: | |
value = repr(data).lower() | |
# Note that in some cases `repr(data)` represents a float number | |
# without the decimal parts. For instance: | |
# >>> repr(1e17) | |
# '1e17' | |
# Unfortunately, this is not a valid float representation according | |
# to the definition of the `!!float` tag. We fix this by adding | |
# '.0' before the 'e' symbol. | |
if '.' not in value and 'e' in value: | |
value = value.replace('e', '.0e', 1) | |
return self.represent_scalar('tag:yaml.org,2002:float', value) | |
def represent_list(self, data): | |
#pairs = (len(data) > 0 and isinstance(data, list)) | |
#if pairs: | |
# for item in data: | |
# if not isinstance(item, tuple) or len(item) != 2: | |
# pairs = False | |
# break | |
#if not pairs: | |
return self.represent_sequence('tag:yaml.org,2002:seq', data) | |
#value = [] | |
#for item_key, item_value in data: | |
# value.append(self.represent_mapping(u'tag:yaml.org,2002:map', | |
# [(item_key, item_value)])) | |
#return SequenceNode(u'tag:yaml.org,2002:pairs', value) | |
def represent_dict(self, data): | |
return self.represent_mapping('tag:yaml.org,2002:map', data) | |
def represent_set(self, data): | |
value = {} | |
for key in data: | |
value[key] = None | |
return self.represent_mapping('tag:yaml.org,2002:set', value) | |
def represent_date(self, data): | |
value = data.isoformat() | |
return self.represent_scalar('tag:yaml.org,2002:timestamp', value) | |
def represent_datetime(self, data): | |
value = data.isoformat(' ') | |
return self.represent_scalar('tag:yaml.org,2002:timestamp', value) | |
def represent_yaml_object(self, tag, data, cls, flow_style=None): | |
if hasattr(data, '__getstate__'): | |
state = data.__getstate__() | |
else: | |
state = data.__dict__.copy() | |
return self.represent_mapping(tag, state, flow_style=flow_style) | |
def represent_undefined(self, data): | |
raise RepresenterError("cannot represent an object", data) | |
SafeRepresenter.add_representer(type(None), | |
SafeRepresenter.represent_none) | |
SafeRepresenter.add_representer(str, | |
SafeRepresenter.represent_str) | |
SafeRepresenter.add_representer(bytes, | |
SafeRepresenter.represent_binary) | |
SafeRepresenter.add_representer(bool, | |
SafeRepresenter.represent_bool) | |
SafeRepresenter.add_representer(int, | |
SafeRepresenter.represent_int) | |
SafeRepresenter.add_representer(float, | |
SafeRepresenter.represent_float) | |
SafeRepresenter.add_representer(list, | |
SafeRepresenter.represent_list) | |
SafeRepresenter.add_representer(tuple, | |
SafeRepresenter.represent_list) | |
SafeRepresenter.add_representer(dict, | |
SafeRepresenter.represent_dict) | |
SafeRepresenter.add_representer(set, | |
SafeRepresenter.represent_set) | |
SafeRepresenter.add_representer(datetime.date, | |
SafeRepresenter.represent_date) | |
SafeRepresenter.add_representer(datetime.datetime, | |
SafeRepresenter.represent_datetime) | |
SafeRepresenter.add_representer(None, | |
SafeRepresenter.represent_undefined) | |
class Representer(SafeRepresenter): | |
def represent_complex(self, data): | |
if data.imag == 0.0: | |
data = '%r' % data.real | |
elif data.real == 0.0: | |
data = '%rj' % data.imag | |
elif data.imag > 0: | |
data = '%r+%rj' % (data.real, data.imag) | |
else: | |
data = '%r%rj' % (data.real, data.imag) | |
return self.represent_scalar('tag:yaml.org,2002:python/complex', data) | |
def represent_tuple(self, data): | |
return self.represent_sequence('tag:yaml.org,2002:python/tuple', data) | |
def represent_name(self, data): | |
name = '%s.%s' % (data.__module__, data.__name__) | |
return self.represent_scalar('tag:yaml.org,2002:python/name:'+name, '') | |
def represent_module(self, data): | |
return self.represent_scalar( | |
'tag:yaml.org,2002:python/module:'+data.__name__, '') | |
def represent_object(self, data): | |
# We use __reduce__ API to save the data. data.__reduce__ returns | |
# a tuple of length 2-5: | |
# (function, args, state, listitems, dictitems) | |
# For reconstructing, we calls function(*args), then set its state, | |
# listitems, and dictitems if they are not None. | |
# A special case is when function.__name__ == '__newobj__'. In this | |
# case we create the object with args[0].__new__(*args). | |
# Another special case is when __reduce__ returns a string - we don't | |
# support it. | |
# We produce a !!python/object, !!python/object/new or | |
# !!python/object/apply node. | |
cls = type(data) | |
if cls in copyreg.dispatch_table: | |
reduce = copyreg.dispatch_table[cls](data) | |
elif hasattr(data, '__reduce_ex__'): | |
reduce = data.__reduce_ex__(2) | |
elif hasattr(data, '__reduce__'): | |
reduce = data.__reduce__() | |
else: | |
raise RepresenterError("cannot represent an object", data) | |
reduce = (list(reduce)+[None]*5)[:5] | |
function, args, state, listitems, dictitems = reduce | |
args = list(args) | |
if state is None: | |
state = {} | |
if listitems is not None: | |
listitems = list(listitems) | |
if dictitems is not None: | |
dictitems = dict(dictitems) | |
if function.__name__ == '__newobj__': | |
function = args[0] | |
args = args[1:] | |
tag = 'tag:yaml.org,2002:python/object/new:' | |
newobj = True | |
else: | |
tag = 'tag:yaml.org,2002:python/object/apply:' | |
newobj = False | |
function_name = '%s.%s' % (function.__module__, function.__name__) | |
if not args and not listitems and not dictitems \ | |
and isinstance(state, dict) and newobj: | |
return self.represent_mapping( | |
'tag:yaml.org,2002:python/object:'+function_name, state) | |
if not listitems and not dictitems \ | |
and isinstance(state, dict) and not state: | |
return self.represent_sequence(tag+function_name, args) | |
value = {} | |
if args: | |
value['args'] = args | |
if state or not isinstance(state, dict): | |
value['state'] = state | |
if listitems: | |
value['listitems'] = listitems | |
if dictitems: | |
value['dictitems'] = dictitems | |
return self.represent_mapping(tag+function_name, value) | |
def represent_ordered_dict(self, data): | |
# Provide uniform representation across different Python versions. | |
data_type = type(data) | |
tag = 'tag:yaml.org,2002:python/object/apply:%s.%s' \ | |
% (data_type.__module__, data_type.__name__) | |
items = [[key, value] for key, value in data.items()] | |
return self.represent_sequence(tag, [items]) | |
Representer.add_representer(complex, | |
Representer.represent_complex) | |
Representer.add_representer(tuple, | |
Representer.represent_tuple) | |
Representer.add_multi_representer(type, | |
Representer.represent_name) | |
Representer.add_representer(collections.OrderedDict, | |
Representer.represent_ordered_dict) | |
Representer.add_representer(types.FunctionType, | |
Representer.represent_name) | |
Representer.add_representer(types.BuiltinFunctionType, | |
Representer.represent_name) | |
Representer.add_representer(types.ModuleType, | |
Representer.represent_module) | |
Representer.add_multi_representer(object, | |
Representer.represent_object) | |