blob: 92f9221f807394a859cdba1122f3bbc280f96ff9 [file] [log] [blame]
__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()