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_H
18#define AAPT_LINKER_H
19
20#include "Resolver.h"
21#include "ResourceTable.h"
22#include "ResourceValues.h"
23#include "Source.h"
24#include "StringPiece.h"
25
26#include <androidfw/AssetManager.h>
27#include <map>
28#include <memory>
29#include <ostream>
30#include <set>
31#include <vector>
32
33namespace aapt {
34
35/**
36 * The Linker has two jobs. It follows resource references
37 * and verifies that their targert exists and that their
38 * types are compatible. The Linker will also assign resource
39 * IDs and fill in all the dependent references with the newly
40 * assigned resource IDs.
41 *
42 * To do this, the Linker builds a graph of references. This
43 * can be useful to do other analysis, like building a
44 * dependency graph of source files. The hope is to be able to
45 * add functionality that operates on the graph without
46 * overcomplicating the Linker.
47 *
48 * TODO(adamlesinski): Build the graph first then run the separate
49 * steps over the graph.
50 */
51class Linker : ValueVisitor {
52public:
53    struct Options {
54        /**
55         * Assign resource Ids to references when linking.
56         * When building a static library, set this to false.
57         */
58        bool linkResourceIds = true;
59    };
60
61    /**
62     * Create a Linker for the given resource table with the sources available in
63     * IResolver. IResolver should contain the ResourceTable as a source too.
64     */
65    Linker(const std::shared_ptr<ResourceTable>& table,
66           const std::shared_ptr<IResolver>& resolver, const Options& options);
67
68    Linker(const Linker&) = delete;
69
70    virtual ~Linker() = default;
71
72    /**
73     * Entry point to the linker. Assigns resource IDs, follows references,
74     * and validates types. Returns true if all references to defined values
75     * are type-compatible. Missing resource references are recorded but do
76     * not cause this method to fail.
77     */
78    bool linkAndValidate();
79
80    /**
81     * Returns any references to resources that were not defined in any of the
82     * sources.
83     */
84    using ResourceNameToSourceMap = std::map<ResourceName, std::vector<SourceLine>>;
85    const ResourceNameToSourceMap& getUnresolvedReferences() const;
86
87protected:
88    virtual void doResolveReference(Reference& reference, const SourceLine& source);
89    virtual const Attribute* doResolveAttribute(Reference& attribute, const SourceLine& source);
90
91    std::shared_ptr<IResolver> mResolver;
92
93private:
94    struct Args : public ValueVisitorArgs {
95        Args(const ResourceNameRef& r, const SourceLine& s);
96
97        const ResourceNameRef& referrer;
98        const SourceLine& source;
99    };
100
101    //
102    // Overrides of ValueVisitor
103    //
104    void visit(Reference& reference, ValueVisitorArgs& args) override;
105    void visit(Attribute& attribute, ValueVisitorArgs& args) override;
106    void visit(Styleable& styleable, ValueVisitorArgs& args) override;
107    void visit(Style& style, ValueVisitorArgs& args) override;
108    void visit(Array& array, ValueVisitorArgs& args) override;
109    void visit(Plural& plural, ValueVisitorArgs& args) override;
110
111    void processAttributeValue(const ResourceNameRef& name, const SourceLine& source,
112                               const Attribute& attr, std::unique_ptr<Item>& value);
113
114    void addUnresolvedSymbol(const ResourceNameRef& name, const SourceLine& source);
115
116    std::shared_ptr<ResourceTable> mTable;
117    std::map<ResourceName, std::vector<SourceLine>> mUnresolvedSymbols;
118    Options mOptions;
119    bool mError;
120};
121
122} // namespace aapt
123
124#endif // AAPT_LINKER_H
125