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_REFERENCELINKER_H
18 #define AAPT_LINKER_REFERENCELINKER_H
19 
20 #include "android-base/macros.h"
21 
22 #include "Resource.h"
23 #include "ResourceValues.h"
24 #include "link/Linkers.h"
25 #include "process/IResourceTableConsumer.h"
26 #include "process/SymbolTable.h"
27 #include "xml/XmlDom.h"
28 
29 namespace aapt {
30 
31 // Resolves all references to resources in the ResourceTable and assigns them IDs.
32 // The ResourceTable must already have IDs assigned to each resource.
33 // Once the ResourceTable is processed by this linker, it is ready to be flattened.
34 class ReferenceLinker : public IResourceTableConsumer {
35  public:
36   ReferenceLinker() = default;
37 
38   // Performs name mangling and looks up the resource in the symbol table. Uses the callsite's
39   // package if the reference has no package name defined (implicit).
40   // Returns nullptr if the symbol was not found.
41   static const SymbolTable::Symbol* ResolveSymbol(const Reference& reference,
42                                                   const CallSite& callsite,
43                                                   IAaptContext* context,
44                                                   SymbolTable* symbols);
45 
46   // Performs name mangling and looks up the resource in the symbol table. If the symbol is not
47   // visible by the reference at the callsite, nullptr is returned.
48   // `out_error` holds the error message.
49   static const SymbolTable::Symbol* ResolveSymbolCheckVisibility(const Reference& reference,
50                                                                  const CallSite& callsite,
51                                                                  IAaptContext* context,
52                                                                  SymbolTable* symbols,
53                                                                  std::string* out_error);
54 
55   // Same as ResolveSymbolCheckVisibility(), but also makes sure the symbol is an attribute.
56   // That is, the return value will have a non-null value for ISymbolTable::Symbol::attribute.
57   static const SymbolTable::Symbol* ResolveAttributeCheckVisibility(const Reference& reference,
58                                                                     const CallSite& callsite,
59                                                                     IAaptContext* context,
60                                                                     SymbolTable* symbols,
61                                                                     std::string* out_error);
62 
63   // Resolves the attribute reference and returns an xml::AaptAttribute if successful.
64   // If resolution fails, outError holds the error message.
65   static Maybe<xml::AaptAttribute> CompileXmlAttribute(const Reference& reference,
66                                                        const CallSite& callsite,
67                                                        IAaptContext* context,
68                                                        SymbolTable* symbols,
69                                                        std::string* out_error);
70 
71   // Writes the resource name to the DiagMessage, using the
72   // "orig_name (aka <transformed_name>)" syntax.
73   static void WriteResourceName(const Reference& orig, const CallSite& callsite,
74                                 const xml::IPackageDeclStack* decls, DiagMessage* out_msg);
75 
76   // Same as WriteResourceName but omits the 'attr' part.
77   static void WriteAttributeName(const Reference& ref, const CallSite& callsite,
78                                  const xml::IPackageDeclStack* decls, DiagMessage* out_msg);
79 
80   // Transforms the package name of the reference to the fully qualified package name using
81   // the xml::IPackageDeclStack, then mangles and looks up the symbol. If the symbol is visible
82   // to the reference at the callsite, the reference is updated with an ID.
83   // Returns false on failure, and an error message is logged to the IDiagnostics in the context.
84   static bool LinkReference(const CallSite& callsite, Reference* reference, IAaptContext* context,
85                             SymbolTable* symbols, const xml::IPackageDeclStack* decls);
86 
87   // Links all references in the ResourceTable.
88   bool Consume(IAaptContext* context, ResourceTable* table) override;
89 
90  private:
91   DISALLOW_COPY_AND_ASSIGN(ReferenceLinker);
92 };
93 
94 }  // namespace aapt
95 
96 #endif /* AAPT_LINKER_REFERENCELINKER_H */
97