tools/aapt2/link/ReferenceLinker.cpp - platform/frameworks/base - Git at Google

 /*
  * Copyright (C) 2015 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include "link/ReferenceLinker.h"

 #include "android-base/logging.h"
 #include "androidfw/ResourceTypes.h"

 #include "Diagnostics.h"
 #include "ResourceTable.h"
 #include "ResourceUtils.h"
 #include "ResourceValues.h"
 #include "ValueVisitor.h"
 #include "link/Linkers.h"
 #include "process/IResourceTableConsumer.h"
 #include "process/SymbolTable.h"
 #include "util/Util.h"
 #include "xml/XmlUtil.h"

 using android::StringPiece;

 namespace aapt {

 namespace {

 /**
  * The ReferenceLinkerVisitor will follow all references and make sure they
  * point
  * to resources that actually exist, either in the local resource table, or as
  * external
  * symbols. Once the target resource has been found, the ID of the resource will
  * be assigned
  * to the reference object.
  *
  * NOTE: All of the entries in the ResourceTable must be assigned IDs.
  */
 class ReferenceLinkerVisitor : public ValueVisitor {
  public:
   using ValueVisitor::Visit;

   ReferenceLinkerVisitor(const CallSite& callsite, IAaptContext* context, SymbolTable* symbols,
                          StringPool* string_pool, xml::IPackageDeclStack* decl)
       : callsite_(callsite),
         context_(context),
         symbols_(symbols),
         package_decls_(decl),
         string_pool_(string_pool) {}

   void Visit(Reference* ref) override {
     if (!ReferenceLinker::LinkReference(callsite_, ref, context_, symbols_, package_decls_)) {
       error_ = true;
     }
   }

   /**
    * We visit the Style specially because during this phase, values of
    * attributes are
    * all RawString values. Now that we are expected to resolve all symbols, we
    * can
    * lookup the attributes to find out which types are allowed for the
    * attributes' values.
    */
   void Visit(Style* style) override {
     if (style->parent) {
       Visit(&style->parent.value());
     }

     for (Style::Entry& entry : style->entries) {
       std::string err_str;

       // Transform the attribute reference so that it is using the fully
       // qualified package
       // name. This will also mark the reference as being able to see private
       // resources if
       // there was a '*' in the reference or if the package came from the
       // private namespace.
       Reference transformed_reference = entry.key;
       TransformReferenceFromNamespace(package_decls_,
                                       context_->GetCompilationPackage(),
                                       &transformed_reference);

       // Find the attribute in the symbol table and check if it is visible from
       // this callsite.
       const SymbolTable::Symbol* symbol = ReferenceLinker::ResolveAttributeCheckVisibility(
           transformed_reference, callsite_, symbols_, &err_str);
       if (symbol) {
         // Assign our style key the correct ID.
         // The ID may not exist.
         entry.key.id = symbol->id;

         // Try to convert the value to a more specific, typed value based on the
         // attribute it is set to.
         entry.value = ParseValueWithAttribute(std::move(entry.value), symbol->attribute.get());

         // Link/resolve the final value (mostly if it's a reference).
         entry.value->Accept(this);

         // Now verify that the type of this item is compatible with the
         // attribute it is defined for. We pass `nullptr` as the DiagMessage so that this
         // check is fast and we avoid creating a DiagMessage when the match is successful.
         if (!symbol->attribute->Matches(*entry.value, nullptr)) {
           // The actual type of this item is incompatible with the attribute.
           DiagMessage msg(entry.key.GetSource());

           // Call the matches method again, this time with a DiagMessage so we
           // fill in the actual error message.
           symbol->attribute->Matches(*entry.value, &msg);
           context_->GetDiagnostics()->Error(msg);
           error_ = true;
         }

       } else {
         DiagMessage msg(entry.key.GetSource());
         msg << "style attribute '";
         ReferenceLinker::WriteResourceName(&msg, entry.key, transformed_reference);
         msg << "' " << err_str;
         context_->GetDiagnostics()->Error(msg);
         error_ = true;
       }
     }
   }

   bool HasError() { return error_; }

  private:
   DISALLOW_COPY_AND_ASSIGN(ReferenceLinkerVisitor);

   /**
    * Transform a RawString value into a more specific, appropriate value, based
    * on the
    * Attribute. If a non RawString value is passed in, this is an identity
    * transform.
    */
   std::unique_ptr<Item> ParseValueWithAttribute(std::unique_ptr<Item> value,
                                                 const Attribute* attr) {
     if (RawString* raw_string = ValueCast<RawString>(value.get())) {
       std::unique_ptr<Item> transformed =
           ResourceUtils::TryParseItemForAttribute(*raw_string->value, attr);

       // If we could not parse as any specific type, try a basic STRING.
       if (!transformed && (attr->type_mask & android::ResTable_map::TYPE_STRING)) {
         util::StringBuilder string_builder;
         string_builder.Append(*raw_string->value);
         if (string_builder) {
           transformed = util::make_unique<String>(string_pool_->MakeRef(string_builder.ToString()));
         }
       }

       if (transformed) {
         return transformed;
       }
     }
     return value;
   }

   const CallSite& callsite_;
   IAaptContext* context_;
   SymbolTable* symbols_;
   xml::IPackageDeclStack* package_decls_;
   StringPool* string_pool_;
   bool error_ = false;
 };

 class EmptyDeclStack : public xml::IPackageDeclStack {
  public:
   EmptyDeclStack() = default;

   Maybe<xml::ExtractedPackage> TransformPackageAlias(
       const StringPiece& alias,
       const StringPiece& local_package) const override {
     if (alias.empty()) {
       return xml::ExtractedPackage{local_package.to_string(), true /* private */};
     }
     return {};
   }

  private:
   DISALLOW_COPY_AND_ASSIGN(EmptyDeclStack);
 };

 }  // namespace

 /**
  * The symbol is visible if it is public, or if the reference to it is
  * requesting private access
  * or if the callsite comes from the same package.
  */
 bool ReferenceLinker::IsSymbolVisible(const SymbolTable::Symbol& symbol,
                                       const Reference& ref,
                                       const CallSite& callsite) {
   if (!symbol.is_public && !ref.private_reference) {
     if (ref.name) {
       return callsite.resource.package == ref.name.value().package;
     } else if (ref.id && symbol.id) {
       return ref.id.value().package_id() == symbol.id.value().package_id();
     } else {
       return false;
     }
   }
   return true;
 }

 const SymbolTable::Symbol* ReferenceLinker::ResolveSymbol(const Reference& reference,
                                                           SymbolTable* symbols) {
   if (reference.name) {
     return symbols->FindByName(reference.name.value());
   } else if (reference.id) {
     return symbols->FindById(reference.id.value());
   } else {
     return nullptr;
   }
 }

 const SymbolTable::Symbol* ReferenceLinker::ResolveSymbolCheckVisibility(const Reference& reference,
                                                                          const CallSite& callsite,
                                                                          SymbolTable* symbols,
                                                                          std::string* out_error) {
   const SymbolTable::Symbol* symbol = ResolveSymbol(reference, symbols);
   if (!symbol) {
     if (out_error) *out_error = "not found";
     return nullptr;
   }

   if (!IsSymbolVisible(*symbol, reference, callsite)) {
     if (out_error) *out_error = "is private";
     return nullptr;
   }
   return symbol;
 }

 const SymbolTable::Symbol* ReferenceLinker::ResolveAttributeCheckVisibility(
     const Reference& reference, const CallSite& callsite, SymbolTable* symbols,
     std::string* out_error) {
   const SymbolTable::Symbol* symbol =
       ResolveSymbolCheckVisibility(reference, callsite, symbols, out_error);
   if (!symbol) {
     return nullptr;
   }

   if (!symbol->attribute) {
     if (out_error) *out_error = "is not an attribute";
     return nullptr;
   }
   return symbol;
 }

 Maybe<xml::AaptAttribute> ReferenceLinker::CompileXmlAttribute(const Reference& reference,
                                                                const CallSite& callsite,
                                                                SymbolTable* symbols,
                                                                std::string* out_error) {
   const SymbolTable::Symbol* symbol =
       ResolveAttributeCheckVisibility(reference, callsite, symbols, out_error);
   if (!symbol) {
     return {};
   }

   if (!symbol->attribute) {
     if (out_error) *out_error = "is not an attribute";
     return {};
   }
   return xml::AaptAttribute(*symbol->attribute, symbol->id);
 }

 void ReferenceLinker::WriteResourceName(DiagMessage* out_msg,
                                         const Reference& orig,
                                         const Reference& transformed) {
   CHECK(out_msg != nullptr);

   if (orig.name) {
     *out_msg << orig.name.value();
     if (transformed.name.value() != orig.name.value()) {
       *out_msg << " (aka " << transformed.name.value() << ")";
     }
   } else {
     *out_msg << orig.id.value();
   }
 }

 bool ReferenceLinker::LinkReference(const CallSite& callsite, Reference* reference,
                                     IAaptContext* context, SymbolTable* symbols,
                                     xml::IPackageDeclStack* decls) {
   CHECK(reference != nullptr);
   if (!reference->name && !reference->id) {
     // This is @null.
     return true;
   }

   Reference transformed_reference = *reference;
   TransformReferenceFromNamespace(decls, context->GetCompilationPackage(), &transformed_reference);

   std::string err_str;
   const SymbolTable::Symbol* s =
       ResolveSymbolCheckVisibility(transformed_reference, callsite, symbols, &err_str);
   if (s) {
     // The ID may not exist. This is fine because of the possibility of building
     // against libraries without assigned IDs.
     // Ex: Linking against own resources when building a static library.
     reference->id = s->id;
     return true;
   }

   DiagMessage error_msg(reference->GetSource());
   error_msg << "resource ";
   WriteResourceName(&error_msg, *reference, transformed_reference);
   error_msg << " " << err_str;
   context->GetDiagnostics()->Error(error_msg);
   return false;
 }

 bool ReferenceLinker::Consume(IAaptContext* context, ResourceTable* table) {
   EmptyDeclStack decl_stack;
   bool error = false;
   for (auto& package : table->packages) {
     for (auto& type : package->types) {
       for (auto& entry : type->entries) {
         // Symbol state information may be lost if there is no value for the
         // resource.
         if (entry->symbol_status.state != SymbolState::kUndefined &&
             entry->values.empty()) {
           context->GetDiagnostics()->Error(
               DiagMessage(entry->symbol_status.source)
               << "no definition for declared symbol '"
               << ResourceNameRef(package->name, type->type, entry->name)
               << "'");
           error = true;
         }

         CallSite callsite = {ResourceNameRef(package->name, type->type, entry->name)};
         ReferenceLinkerVisitor visitor(callsite, context, context->GetExternalSymbols(),
                                        &table->string_pool, &decl_stack);

         for (auto& config_value : entry->values) {
           config_value->value->Accept(&visitor);
         }

         if (visitor.HasError()) {
           error = true;
         }
       }
     }
   }
   return !error;
 }

 }  // namespace aapt
	/*
	* Copyright (C) 2015 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "link/ReferenceLinker.h"

	#include "android-base/logging.h"
	#include "androidfw/ResourceTypes.h"

	#include "Diagnostics.h"
	#include "ResourceTable.h"
	#include "ResourceUtils.h"
	#include "ResourceValues.h"
	#include "ValueVisitor.h"
	#include "link/Linkers.h"
	#include "process/IResourceTableConsumer.h"
	#include "process/SymbolTable.h"
	#include "util/Util.h"
	#include "xml/XmlUtil.h"

	using android::StringPiece;

	namespace aapt {

	namespace {

	/**
	* The ReferenceLinkerVisitor will follow all references and make sure they
	* point
	* to resources that actually exist, either in the local resource table, or as
	* external
	* symbols. Once the target resource has been found, the ID of the resource will
	* be assigned
	* to the reference object.
	*
	* NOTE: All of the entries in the ResourceTable must be assigned IDs.
	*/
	class ReferenceLinkerVisitor : public ValueVisitor {
	public:
	using ValueVisitor::Visit;

	ReferenceLinkerVisitor(const CallSite& callsite, IAaptContext* context, SymbolTable* symbols,
	StringPool* string_pool, xml::IPackageDeclStack* decl)
	: callsite_(callsite),
	context_(context),
	symbols_(symbols),
	package_decls_(decl),
	string_pool_(string_pool) {}

	void Visit(Reference* ref) override {
	if (!ReferenceLinker::LinkReference(callsite_, ref, context_, symbols_, package_decls_)) {
	error_ = true;
	}
	}

	/**
	* We visit the Style specially because during this phase, values of
	* attributes are
	* all RawString values. Now that we are expected to resolve all symbols, we
	* can
	* lookup the attributes to find out which types are allowed for the
	* attributes' values.
	*/
	void Visit(Style* style) override {
	if (style->parent) {
	Visit(&style->parent.value());
	}

	for (Style::Entry& entry : style->entries) {
	std::string err_str;

	// Transform the attribute reference so that it is using the fully
	// qualified package
	// name. This will also mark the reference as being able to see private
	// resources if
	// there was a '*' in the reference or if the package came from the
	// private namespace.
	Reference transformed_reference = entry.key;
	TransformReferenceFromNamespace(package_decls_,
	context_->GetCompilationPackage(),
	&transformed_reference);

	// Find the attribute in the symbol table and check if it is visible from
	// this callsite.
	const SymbolTable::Symbol* symbol = ReferenceLinker::ResolveAttributeCheckVisibility(
	transformed_reference, callsite_, symbols_, &err_str);
	if (symbol) {
	// Assign our style key the correct ID.
	// The ID may not exist.
	entry.key.id = symbol->id;

	// Try to convert the value to a more specific, typed value based on the
	// attribute it is set to.
	entry.value = ParseValueWithAttribute(std::move(entry.value), symbol->attribute.get());

	// Link/resolve the final value (mostly if it's a reference).
	entry.value->Accept(this);

	// Now verify that the type of this item is compatible with the
	// attribute it is defined for. We pass `nullptr` as the DiagMessage so that this
	// check is fast and we avoid creating a DiagMessage when the match is successful.
	if (!symbol->attribute->Matches(*entry.value, nullptr)) {
	// The actual type of this item is incompatible with the attribute.
	DiagMessage msg(entry.key.GetSource());

	// Call the matches method again, this time with a DiagMessage so we
	// fill in the actual error message.
	symbol->attribute->Matches(*entry.value, &msg);
	context_->GetDiagnostics()->Error(msg);
	error_ = true;
	}

	} else {
	DiagMessage msg(entry.key.GetSource());
	msg << "style attribute '";
	ReferenceLinker::WriteResourceName(&msg, entry.key, transformed_reference);
	msg << "' " << err_str;
	context_->GetDiagnostics()->Error(msg);
	error_ = true;
	}
	}
	}

	bool HasError() { return error_; }

	private:
	DISALLOW_COPY_AND_ASSIGN(ReferenceLinkerVisitor);

	/**
	* Transform a RawString value into a more specific, appropriate value, based
	* on the
	* Attribute. If a non RawString value is passed in, this is an identity
	* transform.
	*/
	std::unique_ptr<Item> ParseValueWithAttribute(std::unique_ptr<Item> value,
	const Attribute* attr) {
	if (RawString* raw_string = ValueCast<RawString>(value.get())) {
	std::unique_ptr<Item> transformed =
	ResourceUtils::TryParseItemForAttribute(*raw_string->value, attr);

	// If we could not parse as any specific type, try a basic STRING.
	if (!transformed && (attr->type_mask & android::ResTable_map::TYPE_STRING)) {
	util::StringBuilder string_builder;
	string_builder.Append(*raw_string->value);
	if (string_builder) {
	transformed = util::make_unique<String>(string_pool_->MakeRef(string_builder.ToString()));
	}
	}

	if (transformed) {
	return transformed;
	}
	}
	return value;
	}

	const CallSite& callsite_;
	IAaptContext* context_;
	SymbolTable* symbols_;
	xml::IPackageDeclStack* package_decls_;
	StringPool* string_pool_;
	bool error_ = false;
	};

	class EmptyDeclStack : public xml::IPackageDeclStack {
	public:
	EmptyDeclStack() = default;

	Maybe<xml::ExtractedPackage> TransformPackageAlias(
	const StringPiece& alias,
	const StringPiece& local_package) const override {
	if (alias.empty()) {
	return xml::ExtractedPackage{local_package.to_string(), true /* private */};
	}
	return {};
	}

	private:
	DISALLOW_COPY_AND_ASSIGN(EmptyDeclStack);
	};

	} // namespace

	/**
	* The symbol is visible if it is public, or if the reference to it is
	* requesting private access
	* or if the callsite comes from the same package.
	*/
	bool ReferenceLinker::IsSymbolVisible(const SymbolTable::Symbol& symbol,
	const Reference& ref,
	const CallSite& callsite) {
	if (!symbol.is_public && !ref.private_reference) {
	if (ref.name) {
	return callsite.resource.package == ref.name.value().package;
	} else if (ref.id && symbol.id) {
	return ref.id.value().package_id() == symbol.id.value().package_id();
	} else {
	return false;
	}
	}
	return true;
	}

	const SymbolTable::Symbol* ReferenceLinker::ResolveSymbol(const Reference& reference,
	SymbolTable* symbols) {
	if (reference.name) {
	return symbols->FindByName(reference.name.value());
	} else if (reference.id) {
	return symbols->FindById(reference.id.value());
	} else {
	return nullptr;
	}
	}

	const SymbolTable::Symbol* ReferenceLinker::ResolveSymbolCheckVisibility(const Reference& reference,
	const CallSite& callsite,
	SymbolTable* symbols,
	std::string* out_error) {
	const SymbolTable::Symbol* symbol = ResolveSymbol(reference, symbols);
	if (!symbol) {
	if (out_error) *out_error = "not found";
	return nullptr;
	}

	if (!IsSymbolVisible(*symbol, reference, callsite)) {
	if (out_error) *out_error = "is private";
	return nullptr;
	}
	return symbol;
	}

	const SymbolTable::Symbol* ReferenceLinker::ResolveAttributeCheckVisibility(
	const Reference& reference, const CallSite& callsite, SymbolTable* symbols,
	std::string* out_error) {
	const SymbolTable::Symbol* symbol =
	ResolveSymbolCheckVisibility(reference, callsite, symbols, out_error);
	if (!symbol) {
	return nullptr;
	}

	if (!symbol->attribute) {
	if (out_error) *out_error = "is not an attribute";
	return nullptr;
	}
	return symbol;
	}

	Maybe<xml::AaptAttribute> ReferenceLinker::CompileXmlAttribute(const Reference& reference,
	const CallSite& callsite,
	SymbolTable* symbols,
	std::string* out_error) {
	const SymbolTable::Symbol* symbol =
	ResolveAttributeCheckVisibility(reference, callsite, symbols, out_error);
	if (!symbol) {
	return {};
	}

	if (!symbol->attribute) {
	if (out_error) *out_error = "is not an attribute";
	return {};
	}
	return xml::AaptAttribute(*symbol->attribute, symbol->id);
	}

	void ReferenceLinker::WriteResourceName(DiagMessage* out_msg,
	const Reference& orig,
	const Reference& transformed) {
	CHECK(out_msg != nullptr);

	if (orig.name) {
	*out_msg << orig.name.value();
	if (transformed.name.value() != orig.name.value()) {
	*out_msg << " (aka " << transformed.name.value() << ")";
	}
	} else {
	*out_msg << orig.id.value();
	}
	}

	bool ReferenceLinker::LinkReference(const CallSite& callsite, Reference* reference,
	IAaptContext* context, SymbolTable* symbols,
	xml::IPackageDeclStack* decls) {
	CHECK(reference != nullptr);
	if (!reference->name && !reference->id) {
	// This is @null.
	return true;
	}

	Reference transformed_reference = *reference;
	TransformReferenceFromNamespace(decls, context->GetCompilationPackage(), &transformed_reference);

	std::string err_str;
	const SymbolTable::Symbol* s =
	ResolveSymbolCheckVisibility(transformed_reference, callsite, symbols, &err_str);
	if (s) {
	// The ID may not exist. This is fine because of the possibility of building
	// against libraries without assigned IDs.
	// Ex: Linking against own resources when building a static library.
	reference->id = s->id;
	return true;
	}

	DiagMessage error_msg(reference->GetSource());
	error_msg << "resource ";
	WriteResourceName(&error_msg, *reference, transformed_reference);
	error_msg << " " << err_str;
	context->GetDiagnostics()->Error(error_msg);
	return false;
	}

	bool ReferenceLinker::Consume(IAaptContext* context, ResourceTable* table) {
	EmptyDeclStack decl_stack;
	bool error = false;
	for (auto& package : table->packages) {
	for (auto& type : package->types) {
	for (auto& entry : type->entries) {
	// Symbol state information may be lost if there is no value for the
	// resource.
	if (entry->symbol_status.state != SymbolState::kUndefined &&
	entry->values.empty()) {
	context->GetDiagnostics()->Error(
	DiagMessage(entry->symbol_status.source)
	<< "no definition for declared symbol '"
	<< ResourceNameRef(package->name, type->type, entry->name)
	<< "'");
	error = true;
	}

	CallSite callsite = {ResourceNameRef(package->name, type->type, entry->name)};
	ReferenceLinkerVisitor visitor(callsite, context, context->GetExternalSymbols(),
	&table->string_pool, &decl_stack);

	for (auto& config_value : entry->values) {
	config_value->value->Accept(&visitor);
	}

	if (visitor.HasError()) {
	error = true;
	}
	}
	}
	}
	return !error;
	}

	} // namespace aapt