__all__ = ['Serializer', 'SerializerError'] from .error import YAMLError from .events import * from .nodes import * class SerializerError(YAMLError): pass class Serializer: ANCHOR_TEMPLATE = 'id%03d' def __init__(self, encoding=None, explicit_start=None, explicit_end=None, version=None, tags=None): self.use_encoding = encoding self.use_explicit_start = explicit_start self.use_explicit_end = explicit_end self.use_version = version self.use_tags = tags self.serialized_nodes = {} self.anchors = {} self.last_anchor_id = 0 self.closed = None def open(self): if self.closed is None: self.emit(StreamStartEvent(encoding=self.use_encoding)) self.closed = False elif self.closed: raise SerializerError("serializer is closed") else: raise SerializerError("serializer is already opened") def close(self): if self.closed is None: raise SerializerError("serializer is not opened") elif not self.closed: self.emit(StreamEndEvent()) self.closed = True #def __del__(self): # self.close() def serialize(self, node): if self.closed is None: raise SerializerError("serializer is not opened") elif self.closed: raise SerializerError("serializer is closed") self.emit(DocumentStartEvent(explicit=self.use_explicit_start, version=self.use_version, tags=self.use_tags)) self.anchor_node(node) self.serialize_node(node, None, None) self.emit(DocumentEndEvent(explicit=self.use_explicit_end)) self.serialized_nodes = {} self.anchors = {} self.last_anchor_id = 0 def anchor_node(self, node): if node in self.anchors: if self.anchors[node] is None: self.anchors[node] = self.generate_anchor(node) else: self.anchors[node] = None if isinstance(node, SequenceNode): for item in node.value: self.anchor_node(item) elif isinstance(node, MappingNode): for key, value in node.value: self.anchor_node(key) self.anchor_node(value) def generate_anchor(self, node): self.last_anchor_id += 1 return self.ANCHOR_TEMPLATE % self.last_anchor_id def serialize_node(self, node, parent, index): alias = self.anchors[node] if node in self.serialized_nodes: self.emit(AliasEvent(alias)) else: self.serialized_nodes[node] = True self.descend_resolver(parent, index) if isinstance(node, ScalarNode): detected_tag = self.resolve(ScalarNode, node.value, (True, False)) default_tag = self.resolve(ScalarNode, node.value, (False, True)) implicit = (node.tag == detected_tag), (node.tag == default_tag) self.emit(ScalarEvent(alias, node.tag, implicit, node.value, style=node.style)) elif isinstance(node, SequenceNode): implicit = (node.tag == self.resolve(SequenceNode, node.value, True)) self.emit(SequenceStartEvent(alias, node.tag, implicit, flow_style=node.flow_style)) index = 0 for item in node.value: self.serialize_node(item, node, index) index += 1 self.emit(SequenceEndEvent()) elif isinstance(node, MappingNode): implicit = (node.tag == self.resolve(MappingNode, node.value, True)) self.emit(MappingStartEvent(alias, node.tag, implicit, flow_style=node.flow_style)) for key, value in node.value: self.serialize_node(key, node, None) self.serialize_node(value, node, key) self.emit(MappingEndEvent()) self.ascend_resolver()