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