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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_LINKERS_H
     18 #define AAPT_LINKER_LINKERS_H
     19 
     20 #include <set>
     21 #include <unordered_set>
     22 
     23 #include "android-base/macros.h"
     24 #include "androidfw/StringPiece.h"
     25 
     26 #include "Resource.h"
     27 #include "SdkConstants.h"
     28 #include "process/IResourceTableConsumer.h"
     29 #include "xml/XmlDom.h"
     30 
     31 namespace aapt {
     32 
     33 class ResourceTable;
     34 class ResourceEntry;
     35 struct ConfigDescription;
     36 
     37 // Defines the context in which a resource value is defined. Most resources are defined with the
     38 // implicit package name of their compilation context. Understanding the package name of a resource
     39 // allows to determine visibility of other symbols which may or may not have their packages defined.
     40 struct CallSite {
     41   std::string package;
     42 };
     43 
     44 // Determines whether a versioned resource should be created. If a versioned resource already
     45 // exists, it takes precedence.
     46 bool ShouldGenerateVersionedResource(const ResourceEntry* entry, const ConfigDescription& config,
     47                                      const ApiVersion sdk_version_to_generate);
     48 
     49 // Finds the next largest ApiVersion of the config which is identical to the given config except
     50 // for sdkVersion.
     51 ApiVersion FindNextApiVersionForConfig(const ResourceEntry* entry, const ConfigDescription& config);
     52 
     53 class AutoVersioner : public IResourceTableConsumer {
     54  public:
     55   AutoVersioner() = default;
     56 
     57   bool Consume(IAaptContext* context, ResourceTable* table) override;
     58 
     59  private:
     60   DISALLOW_COPY_AND_ASSIGN(AutoVersioner);
     61 };
     62 
     63 // If any attribute resource values are defined as public, this consumer will move all private
     64 // attribute resource values to a private ^private-attr type, avoiding backwards compatibility
     65 // issues with new apps running on old platforms.
     66 //
     67 // The Android platform ignores resource attributes it doesn't recognize, so an app developer can
     68 // use new attributes in their layout XML files without worrying about versioning. This assumption
     69 // actually breaks on older platforms. OEMs may add private attributes that are used internally.
     70 // AAPT originally assigned all private attributes IDs immediately proceeding the public attributes'
     71 // IDs.
     72 //
     73 // This means that on a newer Android platform, an ID previously assigned to a private attribute
     74 // may end up assigned to a public attribute.
     75 //
     76 // App developers assume using the newer attribute is safe on older platforms because it will
     77 // be ignored. Instead, the platform thinks the new attribute is an older, private attribute and
     78 // will interpret it as such. This leads to unintended styling and exceptions thrown due to
     79 // unexpected types.
     80 //
     81 // By moving the private attributes to a completely different type, this ID conflict will never
     82 // occur.
     83 class PrivateAttributeMover : public IResourceTableConsumer {
     84  public:
     85   PrivateAttributeMover() = default;
     86 
     87   bool Consume(IAaptContext* context, ResourceTable* table) override;
     88 
     89  private:
     90   DISALLOW_COPY_AND_ASSIGN(PrivateAttributeMover);
     91 };
     92 
     93 class ResourceConfigValue;
     94 
     95 class ProductFilter : public IResourceTableConsumer {
     96  public:
     97   using ResourceConfigValueIter = std::vector<std::unique_ptr<ResourceConfigValue>>::iterator;
     98 
     99   explicit ProductFilter(std::unordered_set<std::string> products) : products_(products) {
    100   }
    101 
    102   ResourceConfigValueIter SelectProductToKeep(
    103       const ResourceNameRef& name, const ResourceConfigValueIter begin,
    104       const ResourceConfigValueIter end, IDiagnostics* diag);
    105 
    106   bool Consume(IAaptContext* context, ResourceTable* table) override;
    107 
    108  private:
    109   DISALLOW_COPY_AND_ASSIGN(ProductFilter);
    110 
    111   std::unordered_set<std::string> products_;
    112 };
    113 
    114 // Removes namespace nodes and URI information from the XmlResource.
    115 //
    116 // Once an XmlResource is processed by this consumer, it is no longer able to have its attributes
    117 // parsed. As such, this XmlResource must have already been processed by XmlReferenceLinker.
    118 class XmlNamespaceRemover : public IXmlResourceConsumer {
    119  public:
    120   explicit XmlNamespaceRemover(bool keep_uris = false) : keep_uris_(keep_uris){};
    121 
    122   bool Consume(IAaptContext* context, xml::XmlResource* resource) override;
    123 
    124  private:
    125   DISALLOW_COPY_AND_ASSIGN(XmlNamespaceRemover);
    126 
    127   bool keep_uris_;
    128 };
    129 
    130 // Resolves attributes in the XmlResource and compiles string values to resource values.
    131 // Once an XmlResource is processed by this linker, it is ready to be flattened.
    132 class XmlReferenceLinker : public IXmlResourceConsumer {
    133  public:
    134   XmlReferenceLinker() = default;
    135 
    136   bool Consume(IAaptContext* context, xml::XmlResource* resource) override;
    137 
    138  private:
    139   DISALLOW_COPY_AND_ASSIGN(XmlReferenceLinker);
    140 };
    141 
    142 }  // namespace aapt
    143 
    144 #endif /* AAPT_LINKER_LINKERS_H */
    145