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      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 "ValueVisitor.h"
     25 #include "link/Linkers.h"
     26 #include "process/IResourceTableConsumer.h"
     27 #include "process/SymbolTable.h"
     28 #include "xml/XmlDom.h"
     29 
     30 namespace aapt {
     31 
     32 /**
     33  * Resolves all references to resources in the ResourceTable and assigns them
     34  * IDs.
     35  * The ResourceTable must already have IDs assigned to each resource.
     36  * Once the ResourceTable is processed by this linker, it is ready to be
     37  * flattened.
     38  */
     39 class ReferenceLinker : public IResourceTableConsumer {
     40  public:
     41   ReferenceLinker() = default;
     42 
     43   /**
     44    * Returns true if the symbol is visible by the reference and from the
     45    * callsite.
     46    */
     47   static bool IsSymbolVisible(const SymbolTable::Symbol& symbol,
     48                               const Reference& ref, const CallSite& callsite);
     49 
     50   /**
     51    * Performs name mangling and looks up the resource in the symbol table.
     52    * Returns nullptr if the symbol was not found.
     53    */
     54   static const SymbolTable::Symbol* ResolveSymbol(const Reference& reference, SymbolTable* symbols);
     55 
     56   /**
     57    * Performs name mangling and looks up the resource in the symbol table. If
     58    * the symbol is not visible by the reference at the callsite, nullptr is
     59    * returned. out_error holds the error message.
     60    */
     61   static const SymbolTable::Symbol* ResolveSymbolCheckVisibility(const Reference& reference,
     62                                                                  const CallSite& callsite,
     63                                                                  SymbolTable* symbols,
     64                                                                  std::string* out_error);
     65 
     66   /**
     67    * Same as resolveSymbolCheckVisibility(), but also makes sure the symbol is
     68    * an attribute.
     69    * That is, the return value will have a non-null value for
     70    * ISymbolTable::Symbol::attribute.
     71    */
     72   static const SymbolTable::Symbol* ResolveAttributeCheckVisibility(const Reference& reference,
     73                                                                     const CallSite& callsite,
     74                                                                     SymbolTable* symbols,
     75                                                                     std::string* out_error);
     76 
     77   /**
     78    * Resolves the attribute reference and returns an xml::AaptAttribute if
     79    * successful.
     80    * If resolution fails, outError holds the error message.
     81    */
     82   static Maybe<xml::AaptAttribute> CompileXmlAttribute(const Reference& reference,
     83                                                        const CallSite& callsite,
     84                                                        SymbolTable* symbols,
     85                                                        std::string* out_error);
     86 
     87   /**
     88    * Writes the resource name to the DiagMessage, using the
     89    * "orig_name (aka <transformed_name>)" syntax.
     90    */
     91   static void WriteResourceName(DiagMessage* out_msg, const Reference& orig,
     92                                 const Reference& transformed);
     93 
     94   /**
     95    * Transforms the package name of the reference to the fully qualified package
     96    * name using
     97    * the xml::IPackageDeclStack, then mangles and looks up the symbol. If the
     98    * symbol is visible
     99    * to the reference at the callsite, the reference is updated with an ID.
    100    * Returns false on failure, and an error message is logged to the
    101    * IDiagnostics in the context.
    102    */
    103   static bool LinkReference(const CallSite& callsite, Reference* reference, IAaptContext* context,
    104                             SymbolTable* symbols, xml::IPackageDeclStack* decls);
    105 
    106   /**
    107    * Links all references in the ResourceTable.
    108    */
    109   bool Consume(IAaptContext* context, ResourceTable* table) override;
    110 
    111  private:
    112   DISALLOW_COPY_AND_ASSIGN(ReferenceLinker);
    113 };
    114 
    115 }  // namespace aapt
    116 
    117 #endif /* AAPT_LINKER_REFERENCELINKER_H */
    118