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-rw-r--r--libs/yaml/serializer.py111
1 files changed, 111 insertions, 0 deletions
diff --git a/libs/yaml/serializer.py b/libs/yaml/serializer.py
new file mode 100644
index 000000000..0bf1e96dc
--- /dev/null
+++ b/libs/yaml/serializer.py
@@ -0,0 +1,111 @@
+
+__all__ = ['Serializer', 'SerializerError']
+
+from error import YAMLError
+from events import *
+from nodes import *
+
+class SerializerError(YAMLError):
+ pass
+
+class Serializer(object):
+
+ ANCHOR_TEMPLATE = u'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()
+