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, SymbolTable* symbols);
43 
44   // Performs name mangling and looks up the resource in the symbol table. If the symbol is not
45   // visible by the reference at the callsite, nullptr is returned.
46   // `out_error` holds the error message.
47   static const SymbolTable::Symbol* ResolveSymbolCheckVisibility(const Reference& reference,
48                                                                  const CallSite& callsite,
49                                                                  SymbolTable* symbols,
50                                                                  std::string* out_error);
51 
52   // Same as ResolveSymbolCheckVisibility(), but also makes sure the symbol is an attribute.
53   // That is, the return value will have a non-null value for ISymbolTable::Symbol::attribute.
54   static const SymbolTable::Symbol* ResolveAttributeCheckVisibility(const Reference& reference,
55                                                                     const CallSite& callsite,
56                                                                     SymbolTable* symbols,
57                                                                     std::string* out_error);
58 
59   // Resolves the attribute reference and returns an xml::AaptAttribute if successful.
60   // If resolution fails, outError holds the error message.
61   static Maybe<xml::AaptAttribute> CompileXmlAttribute(const Reference& reference,
62                                                        const CallSite& callsite,
63                                                        SymbolTable* symbols,
64                                                        std::string* out_error);
65 
66   // Writes the resource name to the DiagMessage, using the
67   // "orig_name (aka <transformed_name>)" syntax.
68   static void WriteResourceName(const Reference& orig, const CallSite& callsite,
69                                 const xml::IPackageDeclStack* decls, DiagMessage* out_msg);
70 
71   // Same as WriteResourceName but omits the 'attr' part.
72   static void WriteAttributeName(const Reference& ref, const CallSite& callsite,
73                                  const xml::IPackageDeclStack* decls, DiagMessage* out_msg);
74 
75   // Transforms the package name of the reference to the fully qualified package name using
76   // the xml::IPackageDeclStack, then mangles and looks up the symbol. If the symbol is visible
77   // to the reference at the callsite, the reference is updated with an ID.
78   // Returns false on failure, and an error message is logged to the IDiagnostics in the context.
79   static bool LinkReference(const CallSite& callsite, Reference* reference, IAaptContext* context,
80                             SymbolTable* symbols, const xml::IPackageDeclStack* decls);
81 
82   // Links all references in the ResourceTable.
83   bool Consume(IAaptContext* context, ResourceTable* table) override;
84 
85  private:
86   DISALLOW_COPY_AND_ASSIGN(ReferenceLinker);
87 };
88 
89 }  // namespace aapt
90 
91 #endif /* AAPT_LINKER_REFERENCELINKER_H */
92