1 /*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #ifndef AAPT_XML_DOM_H
18 #define AAPT_XML_DOM_H
19
20 #include "Logger.h"
21 #include "StringPiece.h"
22
23 #include <istream>
24 #include <libexpat/expat.h>
25 #include <memory>
26 #include <string>
27 #include <vector>
28
29 namespace aapt {
30 namespace xml {
31
32 struct Visitor;
33
34 /**
35 * The type of node. Can be used to downcast to the concrete XML node
36 * class.
37 */
38 enum class NodeType {
39 kNamespace,
40 kElement,
41 kText,
42 };
43
44 /**
45 * Base class for all XML nodes.
46 */
47 struct Node {
48 NodeType type;
49 Node* parent;
50 size_t lineNumber;
51 size_t columnNumber;
52 std::u16string comment;
53 std::vector<std::unique_ptr<Node>> children;
54
55 Node(NodeType type);
56 void addChild(std::unique_ptr<Node> child);
57 virtual std::unique_ptr<Node> clone() const = 0;
58 virtual void accept(Visitor* visitor) = 0;
~NodeNode59 virtual ~Node() {}
60 };
61
62 /**
63 * Base class that implements the visitor methods for a
64 * subclass of Node.
65 */
66 template <typename Derived>
67 struct BaseNode : public Node {
68 BaseNode(NodeType t);
69 virtual void accept(Visitor* visitor) override;
70 };
71
72 /**
73 * A Namespace XML node. Can only have one child.
74 */
75 struct Namespace : public BaseNode<Namespace> {
76 std::u16string namespacePrefix;
77 std::u16string namespaceUri;
78
79 Namespace();
80 virtual std::unique_ptr<Node> clone() const override;
81 };
82
83 /**
84 * An XML attribute.
85 */
86 struct Attribute {
87 std::u16string namespaceUri;
88 std::u16string name;
89 std::u16string value;
90 };
91
92 /**
93 * An Element XML node.
94 */
95 struct Element : public BaseNode<Element> {
96 std::u16string namespaceUri;
97 std::u16string name;
98 std::vector<Attribute> attributes;
99
100 Element();
101 virtual std::unique_ptr<Node> clone() const override;
102 Attribute* findAttribute(const StringPiece16& ns, const StringPiece16& name);
103 xml::Element* findChild(const StringPiece16& ns, const StringPiece16& name);
104 xml::Element* findChildWithAttribute(const StringPiece16& ns, const StringPiece16& name,
105 const xml::Attribute* reqAttr);
106 std::vector<xml::Element*> getChildElements();
107 };
108
109 /**
110 * A Text (CDATA) XML node. Can not have any children.
111 */
112 struct Text : public BaseNode<Text> {
113 std::u16string text;
114
115 Text();
116 virtual std::unique_ptr<Node> clone() const override;
117 };
118
119 /**
120 * Inflates an XML DOM from a text stream, logging errors to the logger.
121 * Returns the root node on success, or nullptr on failure.
122 */
123 std::unique_ptr<Node> inflate(std::istream* in, SourceLogger* logger);
124
125 /**
126 * Inflates an XML DOM from a binary ResXMLTree, logging errors to the logger.
127 * Returns the root node on success, or nullptr on failure.
128 */
129 std::unique_ptr<Node> inflate(const void* data, size_t dataLen, SourceLogger* logger);
130
131 /**
132 * A visitor interface for the different XML Node subtypes.
133 */
134 struct Visitor {
135 virtual void visit(Namespace* node) = 0;
136 virtual void visit(Element* node) = 0;
137 virtual void visit(Text* text) = 0;
138 };
139
140 // Implementations
141
142 template <typename Derived>
BaseNode(NodeType type)143 BaseNode<Derived>::BaseNode(NodeType type) : Node(type) {
144 }
145
146 template <typename Derived>
accept(Visitor * visitor)147 void BaseNode<Derived>::accept(Visitor* visitor) {
148 visitor->visit(static_cast<Derived*>(this));
149 }
150
151 } // namespace xml
152 } // namespace aapt
153
154 #endif // AAPT_XML_DOM_H
155