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1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file | |
2 // for details. All rights reserved. Use of this source code is governed by a | |
3 // BSD-style license that can be found in the LICENSE file. | |
4 | |
5 library yaml.yaml_node; | |
6 | |
7 import 'dart:collection' as collection; | |
8 | |
9 import 'package:collection/collection.dart'; | |
10 import 'package:source_span/source_span.dart'; | |
11 | |
12 import 'event.dart'; | |
13 import 'null_span.dart'; | |
14 import 'style.dart'; | |
15 import 'yaml_node_wrapper.dart'; | |
16 | |
17 /// An interface for parsed nodes from a YAML source tree. | |
18 /// | |
19 /// [YamlMap]s and [YamlList]s implement this interface in addition to the | |
20 /// normal [Map] and [List] interfaces, so any maps and lists will be | |
21 /// [YamlNode]s regardless of how they're accessed. | |
22 /// | |
23 /// Scalars values like strings and numbers, on the other hand, don't have this | |
24 /// interface by default. Instead, they can be accessed as [YamlScalar]s via | |
25 /// [YamlMap.nodes] or [YamlList.nodes]. | |
26 abstract class YamlNode { | |
27 /// The source span for this node. | |
28 /// | |
29 /// [SourceSpan.message] can be used to produce a human-friendly message about | |
30 /// this node. | |
31 SourceSpan get span => _span; | |
32 | |
33 SourceSpan _span; | |
34 | |
35 /// The inner value of this node. | |
36 /// | |
37 /// For [YamlScalar]s, this will return the wrapped value. For [YamlMap] and | |
38 /// [YamlList], it will return [this], since they already implement [Map] and | |
39 /// [List], respectively. | |
40 get value; | |
41 } | |
42 | |
43 /// A read-only [Map] parsed from YAML. | |
44 class YamlMap extends YamlNode with collection.MapMixin, UnmodifiableMapMixin { | |
45 /// A view of [this] where the keys and values are guaranteed to be | |
46 /// [YamlNode]s. | |
47 /// | |
48 /// The key type is `dynamic` to allow values to be accessed using | |
49 /// non-[YamlNode] keys, but [Map.keys] and [Map.forEach] will always expose | |
50 /// them as [YamlNode]s. For example, for `{"foo": [1, 2, 3]}` [nodes] will be | |
51 /// a map from a [YamlScalar] to a [YamlList], but since the key type is | |
52 /// `dynamic` `map.nodes["foo"]` will still work. | |
53 final Map<dynamic, YamlNode> nodes; | |
54 | |
55 /// The style used for the map in the original document. | |
56 final CollectionStyle style; | |
57 | |
58 Map get value => this; | |
59 | |
60 Iterable get keys => nodes.keys.map((node) => node.value); | |
61 | |
62 /// Creates an empty YamlMap. | |
63 /// | |
64 /// This map's [span] won't have useful location information. However, it will | |
65 /// have a reasonable implementation of [SourceSpan.message]. If [sourceUrl] | |
66 /// is passed, it's used as the [SourceSpan.sourceUrl]. | |
67 /// | |
68 /// [sourceUrl] may be either a [String], a [Uri], or `null`. | |
69 factory YamlMap({sourceUrl}) => | |
70 new YamlMapWrapper(const {}, sourceUrl); | |
71 | |
72 /// Wraps a Dart map so that it can be accessed (recursively) like a | |
73 /// [YamlMap]. | |
74 /// | |
75 /// Any [SourceSpan]s returned by this map or its children will be dummies | |
76 /// without useful location information. However, they will have a reasonable | |
77 /// implementation of [SourceSpan.getLocationMessage]. If [sourceUrl] is | |
78 /// passed, it's used as the [SourceSpan.sourceUrl]. | |
79 /// | |
80 /// [sourceUrl] may be either a [String], a [Uri], or `null`. | |
81 factory YamlMap.wrap(Map dartMap, {sourceUrl}) => | |
82 new YamlMapWrapper(dartMap, sourceUrl); | |
83 | |
84 /// Users of the library should not use this constructor. | |
85 YamlMap.internal(Map<dynamic, YamlNode> nodes, SourceSpan span, this.style) | |
86 : nodes = new UnmodifiableMapView<dynamic, YamlNode>(nodes) { | |
87 _span = span; | |
88 } | |
89 | |
90 operator [](key) { | |
91 var node = nodes[key]; | |
92 return node == null ? null : node.value; | |
93 } | |
94 } | |
95 | |
96 // TODO(nweiz): Use UnmodifiableListMixin when issue 18970 is fixed. | |
97 /// A read-only [List] parsed from YAML. | |
98 class YamlList extends YamlNode with collection.ListMixin { | |
99 final List<YamlNode> nodes; | |
100 | |
101 /// The style used for the list in the original document. | |
102 final CollectionStyle style; | |
103 | |
104 List get value => this; | |
105 | |
106 int get length => nodes.length; | |
107 | |
108 set length(int index) { | |
109 throw new UnsupportedError("Cannot modify an unmodifiable List"); | |
110 } | |
111 | |
112 /// Creates an empty YamlList. | |
113 /// | |
114 /// This list's [span] won't have useful location information. However, it | |
115 /// will have a reasonable implementation of [SourceSpan.message]. If | |
116 /// [sourceUrl] is passed, it's used as the [SourceSpan.sourceUrl]. | |
117 /// | |
118 /// [sourceUrl] may be either a [String], a [Uri], or `null`. | |
119 factory YamlList({sourceUrl}) => | |
120 new YamlListWrapper(const [], sourceUrl); | |
121 | |
122 /// Wraps a Dart list so that it can be accessed (recursively) like a | |
123 /// [YamlList]. | |
124 /// | |
125 /// Any [SourceSpan]s returned by this list or its children will be dummies | |
126 /// without useful location information. However, they will have a reasonable | |
127 /// implementation of [SourceSpan.getLocationMessage]. If [sourceUrl] is | |
128 /// passed, it's used as the [SourceSpan.sourceUrl]. | |
129 /// | |
130 /// [sourceUrl] may be either a [String], a [Uri], or `null`. | |
131 factory YamlList.wrap(List dartList, {sourceUrl}) => | |
132 new YamlListWrapper(dartList, sourceUrl); | |
133 | |
134 /// Users of the library should not use this constructor. | |
135 YamlList.internal(List<YamlNode> nodes, SourceSpan span, this.style) | |
136 : nodes = new UnmodifiableListView<YamlNode>(nodes) { | |
137 _span = span; | |
138 } | |
139 | |
140 operator [](int index) => nodes[index].value; | |
141 | |
142 operator []=(int index, value) { | |
143 throw new UnsupportedError("Cannot modify an unmodifiable List"); | |
144 } | |
145 } | |
146 | |
147 /// A wrapped scalar value parsed from YAML. | |
148 class YamlScalar extends YamlNode { | |
149 final value; | |
150 | |
151 /// The style used for the scalar in the original document. | |
152 final ScalarStyle style; | |
153 | |
154 /// Wraps a Dart value in a [YamlScalar]. | |
155 /// | |
156 /// This scalar's [span] won't have useful location information. However, it | |
157 /// will have a reasonable implementation of [SourceSpan.message]. If | |
158 /// [sourceUrl] is passed, it's used as the [SourceSpan.sourceUrl]. | |
159 /// | |
160 /// [sourceUrl] may be either a [String], a [Uri], or `null`. | |
161 YamlScalar.wrap(this.value, {sourceUrl}) | |
162 : style = ScalarStyle.ANY { | |
163 _span = new NullSpan(sourceUrl); | |
164 } | |
165 | |
166 /// Users of the library should not use this constructor. | |
167 YamlScalar.internal(this.value, ScalarEvent scalar) | |
168 : style = scalar.style { | |
169 _span = scalar.span; | |
170 } | |
171 | |
172 /// Users of the library should not use this constructor. | |
173 YamlScalar.internalWithSpan(this.value, SourceSpan span) | |
174 : style = ScalarStyle.ANY { | |
175 _span = span; | |
176 } | |
177 | |
178 String toString() => value.toString(); | |
179 } | |
180 | |
181 /// Sets the source span of a [YamlNode]. | |
182 /// | |
183 /// This method is not exposed publicly. | |
184 void setSpan(YamlNode node, SourceSpan span) { | |
185 node._span = span; | |
186 } | |
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