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_LINKER_LINKERS_H
18#define AAPT_LINKER_LINKERS_H
19
20#include "Resource.h"
21#include "process/IResourceTableConsumer.h"
22#include "xml/XmlDom.h"
23
24#include <set>
25
26namespace aapt {
27
28class ResourceTable;
29class ResourceEntry;
30struct ConfigDescription;
31
32/**
33 * Defines the location in which a value exists. This determines visibility of other
34 * package's private symbols.
35 */
36struct CallSite {
37    ResourceNameRef resource;
38};
39
40/**
41 * Determines whether a versioned resource should be created. If a versioned resource already
42 * exists, it takes precedence.
43 */
44bool shouldGenerateVersionedResource(const ResourceEntry* entry, const ConfigDescription& config,
45                                     const int sdkVersionToGenerate);
46
47struct AutoVersioner : public IResourceTableConsumer {
48    bool consume(IAaptContext* context, ResourceTable* table) override;
49};
50
51struct XmlAutoVersioner : public IXmlResourceConsumer {
52    bool consume(IAaptContext* context, xml::XmlResource* resource) override;
53};
54
55/**
56 * If any attribute resource values are defined as public, this consumer will move all private
57 * attribute resource values to a private ^private-attr type, avoiding backwards compatibility
58 * issues with new apps running on old platforms.
59 *
60 * The Android platform ignores resource attributes it doesn't recognize, so an app developer can
61 * use new attributes in their layout XML files without worrying about versioning. This assumption
62 * actually breaks on older platforms. OEMs may add private attributes that are used internally.
63 * AAPT originally assigned all private attributes IDs immediately proceeding the public attributes'
64 * IDs.
65 *
66 * This means that on a newer Android platform, an ID previously assigned to a private attribute
67 * may end up assigned to a public attribute.
68 *
69 * App developers assume using the newer attribute is safe on older platforms because it will
70 * be ignored. Instead, the platform thinks the new attribute is an older, private attribute and
71 * will interpret it as such. This leads to unintended styling and exceptions thrown due to
72 * unexpected types.
73 *
74 * By moving the private attributes to a completely different type, this ID conflict will never
75 * occur.
76 */
77struct PrivateAttributeMover : public IResourceTableConsumer {
78    bool consume(IAaptContext* context, ResourceTable* table) override;
79};
80
81/**
82 * Resolves attributes in the XmlResource and compiles string values to resource values.
83 * Once an XmlResource is processed by this linker, it is ready to be flattened.
84 */
85class XmlReferenceLinker : public IXmlResourceConsumer {
86private:
87    std::set<int> mSdkLevelsFound;
88
89public:
90    bool consume(IAaptContext* context, xml::XmlResource* resource) override;
91
92    /**
93     * Once the XmlResource has been consumed, this returns the various SDK levels in which
94     * framework attributes used within the XML document were defined.
95     */
96    inline const std::set<int>& getSdkLevels() const {
97        return mSdkLevelsFound;
98    }
99};
100
101} // namespace aapt
102
103#endif /* AAPT_LINKER_LINKERS_H */
104