| |
| __all__ = ['BaseConstructor', 'Constructor', 'ConstructorError', |
| 'YAMLObject', 'YAMLObjectMetaclass'] |
| |
| 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, re |
| |
| 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 = {} |
| merge = None |
| for key_node in node.value: |
| if key_node.tag == u'tag:yaml.org,2002:merge': |
| if merge is not None: |
| raise ConstructorError("while constructing a mapping", node.start_marker, |
| "found duplicate merge key", key_node.start_marker) |
| value_node = node.value[key_node] |
| if isinstance(value_node, MappingNode): |
| merge = [self.construct_mapping(value_node)] |
| elif isinstance(value_node, SequenceNode): |
| merge = [] |
| for subnode in value_node.value: |
| if not isinstance(subnode, MappingNode): |
| raise ConstructorError("while constructing a mapping", |
| node.start_marker, |
| "expected a mapping for merging, but found %s" |
| % subnode.id, subnode.start_marker) |
| merge.append(self.construct_mapping(subnode)) |
| merge.reverse() |
| else: |
| raise ConstructorError("while constructing a mapping", node.start_marker, |
| "expected a mapping or list of mappings for merging, but found %s" |
| % value_node.id, value_node.start_marker) |
| elif key_node.tag == u'tag:yaml.org,2002:value': |
| if '=' in mapping: |
| raise ConstructorError("while construction a mapping", node.start_marker, |
| "found duplicate value key", key_node.start_marker) |
| value = self.construct_object(node.value[key_node]) |
| mapping['='] = value |
| else: |
| 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 |
| if merge is not None: |
| merge.append(mapping) |
| mapping = {} |
| for submapping in merge: |
| mapping.update(submapping) |
| 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] == '-': |
| sign = -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_marker) |
| |
| timestamp_regexp = re.compile( |
| ur'''^(?P<year>[0-9][0-9][0-9][0-9]) |
| -(?P<month>[0-9][0-9]?) |
| -(?P<day>[0-9][0-9]?) |
| (?:(?:[Tt]|[ \t]+) |
| (?P<hour>[0-9][0-9]?) |
| :(?P<minute>[0-9][0-9]) |
| :(?P<second>[0-9][0-9]) |
| (?:\.(?P<fraction>[0-9]*))? |
| (?:[ \t]*(?:Z|(?P<tz_hour>[-+][0-9][0-9]?) |
| (?::(?P<tz_minute>[0-9][0-9])?)?))?)?$''', re.X) |
| |
| def construct_yaml_timestamp(self, node): |
| value = self.construct_scalar(node) |
| match = self.timestamp_regexp.match(node.value) |
| values = match.groupdict() |
| for key in values: |
| if values[key]: |
| values[key] = int(values[key]) |
| else: |
| values[key] = 0 |
| fraction = values['fraction'] |
| if fraction: |
| while 10*fraction < 1000000: |
| fraction *= 10 |
| values['fraction'] = fraction |
| stamp = datetime.datetime(values['year'], values['month'], values['day'], |
| values['hour'], values['minute'], values['second'], values['fraction']) |
| diff = datetime.timedelta(hours=values['tz_hour'], minutes=values['tz_minute']) |
| return stamp-diff |
| |
| def construct_yaml_omap(self, node): |
| # Note: we do not check for duplicate keys, because it's too |
| # CPU-expensive. |
| if not isinstance(node, SequenceNode): |
| raise ConstructorError("while constructing an ordered map", node.start_marker, |
| "expected a sequence, but found %s" % node.id, node.start_marker) |
| omap = [] |
| for subnode in node.value: |
| if not isinstance(subnode, MappingNode): |
| raise ConstructorError("while constructing an ordered map", node.start_marker, |
| "expected a mapping of length 1, but found %s" % subnode.id, |
| subnode.start_marker) |
| if len(subnode.value) != 1: |
| raise ConstructorError("while constructing an ordered map", node.start_marker, |
| "expected a single mapping item, but found %d items" % len(subnode.value), |
| subnode.start_marker) |
| key_node = subnode.value.keys()[0] |
| key = self.construct_object(key_node) |
| value = self.construct_object(subnode.value[key_node]) |
| omap.append((key, value)) |
| return omap |
| |
| def construct_yaml_pairs(self, node): |
| # Note: the same code as `construct_yaml_omap`. |
| if not isinstance(node, SequenceNode): |
| raise ConstructorError("while constructing pairs", node.start_marker, |
| "expected a sequence, but found %s" % node.id, node.start_marker) |
| pairs = [] |
| for subnode in node.value: |
| if not isinstance(subnode, MappingNode): |
| raise ConstructorError("while constructing pairs", node.start_marker, |
| "expected a mapping of length 1, but found %s" % subnode.id, |
| subnode.start_marker) |
| if len(subnode.value) != 1: |
| raise ConstructorError("while constructing pairs", node.start_marker, |
| "expected a single mapping item, but found %d items" % len(subnode.value), |
| subnode.start_marker) |
| key_node = subnode.value.keys()[0] |
| key = self.construct_object(key_node) |
| value = self.construct_object(subnode.value[key_node]) |
| pairs.append((key, value)) |
| return pairs |
| |
| def construct_yaml_set(self, node): |
| value = self.construct_mapping(node) |
| return set(value) |
| |
| def construct_yaml_str(self, node): |
| value = self.construct_scalar(node) |
| try: |
| return str(value) |
| except UnicodeEncodeError: |
| return value |
| |
| def construct_yaml_seq(self, node): |
| return self.construct_sequence(node) |
| |
| def construct_yaml_map(self, node): |
| return self.construct_mapping(node) |
| |
| def construct_undefined(self, node): |
| raise ConstructorError(None, None, |
| "could not determine a constructor for the tag %r" % node.tag.encode('utf-8'), |
| node.start_marker) |
| |
| 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:binary', |
| Constructor.construct_yaml_binary) |
| |
| if datetime_available: |
| Constructor.add_constructor( |
| u'tag:yaml.org,2002:timestamp', |
| Constructor.construct_yaml_timestamp) |
| |
| Constructor.add_constructor( |
| u'tag:yaml.org,2002:omap', |
| Constructor.construct_yaml_omap) |
| |
| Constructor.add_constructor( |
| u'tag:yaml.org,2002:pairs', |
| Constructor.construct_yaml_pairs) |
| |
| Constructor.add_constructor( |
| u'tag:yaml.org,2002:set', |
| Constructor.construct_yaml_set) |
| |
| Constructor.add_constructor( |
| u'tag:yaml.org,2002:str', |
| Constructor.construct_yaml_str) |
| |
| Constructor.add_constructor( |
| u'tag:yaml.org,2002:seq', |
| Constructor.construct_yaml_seq) |
| |
| Constructor.add_constructor( |
| u'tag:yaml.org,2002:map', |
| Constructor.construct_yaml_map) |
| |
| Constructor.add_constructor(None, |
| Constructor.construct_undefined) |
| |
| 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.add_constructor(cls.yaml_tag, cls.from_yaml) |
| |
| class YAMLObject(object): |
| |
| __metaclass__ = YAMLObjectMetaclass |
| |
| yaml_constructor = 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 |
| |
