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from error import *
from nodes import *
try:
import datetime
datetime_available = True
except ImportError:
datetime_available = False
try:
set
except NameError:
from sets import Set as set
import binascii
class ConstructorError(MarkedYAMLError):
pass
class BaseConstructor:
def __init__(self, resolver):
self.resolver = resolver
self.constructed_objects = {}
def check(self):
# If there are more documents available?
return self.resolver.check()
def get(self):
# Construct and return the next document.
if self.resolver.check():
return self.construct_document(self.resolver.get())
def __iter__(self):
# Iterator protocol.
while self.resolver.check():
yield self.construct_document(self.resolver.get())
def construct_document(self, node):
native = self.construct_object(node)
self.constructed_objects = {}
return native
def construct_object(self, node):
if node in self.constructed_objects:
return self.constructed_objects[node]
if node.tag in self.yaml_constructors:
native = self.yaml_constructors[node.tag](self, node)
elif None in self.yaml_constructors:
native = self.yaml_constructors[None](self, node)
elif isinstance(node, ScalarNode):
native = self.construct_scalar(node)
elif isinstance(node, SequenceNode):
native = self.construct_sequence(node)
elif isinstance(node, MappingNode):
native = self.construct_mapping(node)
self.constructed_objects[node] = native
return native
def construct_scalar(self, node):
if not isinstance(node, ScalarNode):
if isinstance(node, MappingNode):
for key_node in node.value:
if key_node.tag == u'tag:yaml.org,2002:value':
return self.construct_scalar(node.value[key_node])
raise ConstructorError(None, None,
"expected a scalar node, but found %s" % node.id,
node.start_marker)
return node.value
def construct_sequence(self, node):
if not isinstance(node, SequenceNode):
raise ConstructorError(None, None,
"expected a sequence node, but found %s" % node.id,
node.start_marker)
return [self.construct_object(child) for child in node.value]
def construct_mapping(self, node):
if not isinstance(node, MappingNode):
raise ConstructorError(None, None,
"expected a mapping node, but found %s" % node.id,
node.start_marker)
mapping = {}
for key_node in node.value:
key = self.construct_object(key_node)
try:
duplicate_key = key in mapping
except TypeError, exc:
raise ConstructorError("while constructing a mapping", node.start_marker,
"found unacceptable key (%s)" % exc, key_node.start_marker)
if duplicate_key:
raise ConstructorError("while constructing a mapping", node.start_marker,
"found duplicate key", key_node.start_marker)
value = self.construct_object(node.value[key_node])
mapping[key] = value
return mapping
def construct_pairs(self, node):
if not isinstance(node, MappingNode):
raise ConstructorError(None, None,
"expected a mapping node, but found %s" % node.id,
node.start_marker)
pairs = []
for key_node in node.value:
key = self.construct_object(key_node)
value = self.construct_object(node.value[key_node])
pairs.append((key, value))
return pairs
def add_constructor(cls, tag, constructor):
if not 'yaml_constructors' in cls.__dict__:
cls.yaml_constructors = cls.yaml_constructors.copy()
cls.yaml_constructors[tag] = constructor
add_constructor = classmethod(add_constructor)
yaml_constructors = {}
class Constructor(BaseConstructor):
def construct_yaml_null(self, node):
self.construct_scalar(node)
return None
bool_values = {
u'y': True,
u'yes': True,
u'n': False,
u'no': False,
u'true': True,
u'false': False,
u'on': True,
u'off': False,
}
def construct_yaml_bool(self, node):
value = self.construct_scalar(node)
return self.bool_values[value.lower()]
def construct_yaml_int(self, node):
value = str(self.construct_scalar(node))
value = value.replace('_', '')
sign = +1
if value[0] == '-':
sign = -1
if value[0] in '+-':
value = value[1:]
if value == '0':
return 0
elif value.startswith('0b'):
return sign*int(value[2:], 2)
elif value.startswith('0x'):
return sign*int(value[2:], 16)
elif value[0] == '0':
return sign*int(value, 8)
elif ':' in value:
digits = [int(part) for part in value.split(':')]
digits.reverse()
base = 1
value = 0
for digit in digits:
value += digit*base
base *= 60
return sign*value
else:
return sign*int(value)
inf_value = 1e300000
nan_value = inf_value/inf_value
def construct_yaml_float(self, node):
value = str(self.construct_scalar(node))
value = value.replace('_', '')
sign = +1
if value[0] == '-':
value = -1
if value[0] in '+-':
value = value[1:]
if value.lower() == '.inf':
return sign*self.inf_value
elif value.lower() == '.nan':
return self.nan_value
elif ':' in value:
digits = [float(part) for part in value.split(':')]
digits.reverse()
base = 1
value = 0.0
for digit in digits:
value += digit*base
base *= 60
return sign*value
else:
return float(value)
def construct_yaml_binary(self, node):
value = self.construct_scalar(node)
try:
return str(value).decode('base64')
except (binascii.Error, UnicodeEncodeError), exc:
raise ConstructorError(None, None,
"failed to decode base64 data: %s" % exc, node.start_mark)
def construct_yaml_str(self, node):
value = self.construct_scalar(node)
try:
return str(value)
except UnicodeEncodeError:
return value
Constructor.add_constructor(
u'tag:yaml.org,2002:null',
Constructor.construct_yaml_null)
Constructor.add_constructor(
u'tag:yaml.org,2002:bool',
Constructor.construct_yaml_bool)
Constructor.add_constructor(
u'tag:yaml.org,2002:int',
Constructor.construct_yaml_int)
Constructor.add_constructor(
u'tag:yaml.org,2002:float',
Constructor.construct_yaml_float)
Constructor.add_constructor(
u'tag:yaml.org,2002:str',
Constructor.construct_yaml_str)
class YAMLObjectMetaclass(type):
def __init__(cls, name, bases, kwds):
super(YAMLObjectMetaclass, cls).__init__(name, bases, kwds)
if 'yaml_tag' in kwds and kwds['yaml_tag'] is not None:
cls.yaml_constructor_class.add_constructor(cls.yaml_tag, cls.from_yaml)
class YAMLObject(object):
__metaclass__ = YAMLObjectMetaclass
yaml_constructor_class = Constructor
yaml_tag = None
def from_yaml(cls, constructor, node):
raise ConstructorError(None, None,
"found undefined constructor for the tag %r"
% node.tag.encode('utf-8'), node.start_marker)
from_yaml = classmethod(from_yaml)
def to_yaml(self):
assert False # needs dumper
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