| 1 | # SPDX-License-Identifier: MIT |
| 2 | |
| 3 | __all__ = ['Serializer', 'SerializerError'] |
| 4 | |
| 5 | from .error import YAMLError |
| 6 | from .events import * |
| 7 | from .nodes import * |
| 8 | |
| 9 | class SerializerError(YAMLError): |
| 10 | pass |
| 11 | |
| 12 | class Serializer: |
| 13 | |
| 14 | ANCHOR_TEMPLATE = 'id%03d' |
| 15 | |
| 16 | def __init__(self, encoding=None, |
| 17 | explicit_start=None, explicit_end=None, version=None, tags=None): |
| 18 | self.use_encoding = encoding |
| 19 | self.use_explicit_start = explicit_start |
| 20 | self.use_explicit_end = explicit_end |
| 21 | self.use_version = version |
| 22 | self.use_tags = tags |
| 23 | self.serialized_nodes = {} |
| 24 | self.anchors = {} |
| 25 | self.last_anchor_id = 0 |
| 26 | self.closed = None |
| 27 | |
| 28 | def open(self): |
| 29 | if self.closed is None: |
| 30 | self.emit(StreamStartEvent(encoding=self.use_encoding)) |
| 31 | self.closed = False |
| 32 | elif self.closed: |
| 33 | raise SerializerError("serializer is closed") |
| 34 | else: |
| 35 | raise SerializerError("serializer is already opened") |
| 36 | |
| 37 | def close(self): |
| 38 | if self.closed is None: |
| 39 | raise SerializerError("serializer is not opened") |
| 40 | elif not self.closed: |
| 41 | self.emit(StreamEndEvent()) |
| 42 | self.closed = True |
| 43 | |
| 44 | #def __del__(self): |
| 45 | # self.close() |
| 46 | |
| 47 | def serialize(self, node): |
| 48 | if self.closed is None: |
| 49 | raise SerializerError("serializer is not opened") |
| 50 | elif self.closed: |
| 51 | raise SerializerError("serializer is closed") |
| 52 | self.emit(DocumentStartEvent(explicit=self.use_explicit_start, |
| 53 | version=self.use_version, tags=self.use_tags)) |
| 54 | self.anchor_node(node) |
| 55 | self.serialize_node(node, None, None) |
| 56 | self.emit(DocumentEndEvent(explicit=self.use_explicit_end)) |
| 57 | self.serialized_nodes = {} |
| 58 | self.anchors = {} |
| 59 | self.last_anchor_id = 0 |
| 60 | |
| 61 | def anchor_node(self, node): |
| 62 | if node in self.anchors: |
| 63 | if self.anchors[node] is None: |
| 64 | self.anchors[node] = self.generate_anchor(node) |
| 65 | else: |
| 66 | self.anchors[node] = None |
| 67 | if isinstance(node, SequenceNode): |
| 68 | for item in node.value: |
| 69 | self.anchor_node(item) |
| 70 | elif isinstance(node, MappingNode): |
| 71 | for key, value in node.value: |
| 72 | self.anchor_node(key) |
| 73 | self.anchor_node(value) |
| 74 | |
| 75 | def generate_anchor(self, node): |
| 76 | self.last_anchor_id += 1 |
| 77 | return self.ANCHOR_TEMPLATE % self.last_anchor_id |
| 78 | |
| 79 | def serialize_node(self, node, parent, index): |
| 80 | alias = self.anchors[node] |
| 81 | if node in self.serialized_nodes: |
| 82 | self.emit(AliasEvent(alias)) |
| 83 | else: |
| 84 | self.serialized_nodes[node] = True |
| 85 | self.descend_resolver(parent, index) |
| 86 | if isinstance(node, ScalarNode): |
| 87 | detected_tag = self.resolve(ScalarNode, node.value, (True, False)) |
| 88 | default_tag = self.resolve(ScalarNode, node.value, (False, True)) |
| 89 | implicit = (node.tag == detected_tag), (node.tag == default_tag) |
| 90 | self.emit(ScalarEvent(alias, node.tag, implicit, node.value, |
| 91 | style=node.style)) |
| 92 | elif isinstance(node, SequenceNode): |
| 93 | implicit = (node.tag |
| 94 | == self.resolve(SequenceNode, node.value, True)) |
| 95 | self.emit(SequenceStartEvent(alias, node.tag, implicit, |
| 96 | flow_style=node.flow_style)) |
| 97 | index = 0 |
| 98 | for item in node.value: |
| 99 | self.serialize_node(item, node, index) |
| 100 | index += 1 |
| 101 | self.emit(SequenceEndEvent()) |
| 102 | elif isinstance(node, MappingNode): |
| 103 | implicit = (node.tag |
| 104 | == self.resolve(MappingNode, node.value, True)) |
| 105 | self.emit(MappingStartEvent(alias, node.tag, implicit, |
| 106 | flow_style=node.flow_style)) |
| 107 | for key, value in node.value: |
| 108 | self.serialize_node(key, node, None) |
| 109 | self.serialize_node(value, node, key) |
| 110 | self.emit(MappingEndEvent()) |
| 111 | self.ascend_resolver() |
| 112 |