value/src/main/java/com/google/auto/value/processor/BuilderMethodClassifierForAutoBuilder.java - platform/external/auto - Git at Google

 /*
  * Copyright 2021 Google LLC
  *
  * 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.
  */
 package com.google.auto.value.processor;

 import static com.google.auto.common.MoreStreams.toImmutableBiMap;
 import static com.google.auto.common.MoreStreams.toImmutableMap;

 import com.google.auto.common.MoreElements;
 import com.google.auto.common.MoreTypes;
 import com.google.common.base.Equivalence;
 import com.google.common.base.VerifyException;
 import com.google.common.collect.ImmutableBiMap;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.function.Function;
 import javax.annotation.processing.ProcessingEnvironment;
 import javax.lang.model.element.Element;
 import javax.lang.model.element.ExecutableElement;
 import javax.lang.model.element.TypeElement;
 import javax.lang.model.element.TypeParameterElement;
 import javax.lang.model.element.VariableElement;
 import javax.lang.model.type.TypeMirror;
 import javax.lang.model.type.TypeVariable;
 import javax.lang.model.util.Types;

 class BuilderMethodClassifierForAutoBuilder extends BuilderMethodClassifier<VariableElement> {
   private final ExecutableElement executable;
   private final ImmutableBiMap<VariableElement, String> paramToPropertyName;

   private BuilderMethodClassifierForAutoBuilder(
       ErrorReporter errorReporter,
       ProcessingEnvironment processingEnv,
       ExecutableElement executable,
       TypeMirror builtType,
       TypeElement builderType,
       ImmutableBiMap<VariableElement, String> paramToPropertyName,
       ImmutableMap<String, TypeMirror> rewrittenPropertyTypes) {
     super(errorReporter, processingEnv, builtType, builderType, rewrittenPropertyTypes);
     this.executable = executable;
     this.paramToPropertyName = paramToPropertyName;
   }

   /**
    * Classifies the given methods from a builder type and its ancestors.
    *
    * @param methods the abstract methods in {@code builderType} and its ancestors.
    * @param errorReporter where to report errors.
    * @param processingEnv the ProcessingEnvironment for annotation processing.
    * @param executable the constructor or static method that AutoBuilder will call.
    * @param builtType the type to be built.
    * @param builderType the builder class or interface within {@code ofClass}.
    * @return an {@code Optional} that contains the results of the classification if it was
    *     successful or nothing if it was not.
    */
   static Optional<BuilderMethodClassifier<VariableElement>> classify(
       Iterable<ExecutableElement> methods,
       ErrorReporter errorReporter,
       ProcessingEnvironment processingEnv,
       ExecutableElement executable,
       TypeMirror builtType,
       TypeElement builderType) {
     ImmutableBiMap<VariableElement, String> paramToPropertyName =
         executable.getParameters().stream()
             .collect(toImmutableBiMap(v -> v, v -> v.getSimpleName().toString()));
     ImmutableMap<String, TypeMirror> rewrittenPropertyTypes =
         rewriteParameterTypes(executable, builderType, errorReporter, processingEnv.getTypeUtils());
     BuilderMethodClassifier<VariableElement> classifier =
         new BuilderMethodClassifierForAutoBuilder(
             errorReporter,
             processingEnv,
             executable,
             builtType,
             builderType,
             paramToPropertyName,
             rewrittenPropertyTypes);
     if (classifier.classifyMethods(methods, false)) {
       return Optional.of(classifier);
     } else {
       return Optional.empty();
     }
   }

   // Rewrites the parameter types of the executable so they use the type variables of the builder
   // where appropriate.
   //
   // Suppose we have something like this:
   //
   // static <E> Set<E> singletonSet(E elem) {...}
   //
   // @AutoBuilder(callMethod = "singletonSet")
   // interface SingletonSetBuilder<E> {
   //   SingletonSetBuilder<E> setElem(E elem);
   //   Set<E> build();
   // }
   //
   // We want to check that the type of the setter `setElem` matches the type of the
   // parameter it is setting. But in fact it doesn't: the type of the setter is
   // E-of-SingletonSetBuilder while the type of the parameter is E-of-singletonSet. So we
   // need to rewrite any type variables mentioned in parameters so that they use the corresponding
   // types from the builder. We want to return a map where "elem" is mapped to
   // E-of-SingletonSetBuilder, even though the `elem` that we get from the parameters of
   // singletonSet is going to be E-of-singletonSet. And we also want that to work if the parameter
   // is something more complicated, like List<? extends E>.
   //
   // For the corresponding situation with AutoValue, we have a way of dodging the problem somewhat.
   // For an @AutoValue class Foo<E> with a builder Builder<E>, we can craft a DeclaredType
   // Foo<E> where the E comes from Builder<E>, and we can use Types.asMemberOf to determine the
   // return types of methods (which are what we want to rewrite in that case). But that doesn't
   // work here because singletonSet is static and Types.asMemberOf would have no effect on it.
   //
   // So instead we take the type of each parameter and feed it through a TypeVisitor that rewrites
   // type variables, rewriting from E-of-singletonSet to E-of-SingletonSetBuilder. Then we can use
   // Types.isSameType or Types.isAssignable and it will work as we expect.
   //
   // In principle a similar situation arises with the return type Set<E> of singletonSet versus
   // the return type Set<E> of SingletonSetBuilder.build(). But in fact we only use
   // MoreTypes.equivalence to compare those, and that returns true for distinct type variables if
   // they have the same name and bounds.
   private static ImmutableMap<String, TypeMirror> rewriteParameterTypes(
       ExecutableElement executable,
       TypeElement builderType,
       ErrorReporter errorReporter,
       Types typeUtils) {
     ImmutableList<TypeParameterElement> executableTypeParams = executableTypeParams(executable);
     List<? extends TypeParameterElement> builderTypeParams = builderType.getTypeParameters();
     if (!BuilderSpec.sameTypeParameters(executableTypeParams, builderTypeParams)) {
       errorReporter.abortWithError(
           builderType,
           "[AutoBuilderTypeParams] Builder type parameters %s must match type parameters %s of %s",
           TypeEncoder.typeParametersString(builderTypeParams),
           TypeEncoder.typeParametersString(executableTypeParams),
           AutoBuilderProcessor.executableString(executable));
     }
     if (executableTypeParams.isEmpty()) {
       // Optimization for a common case. No point in doing all that type visiting if we have no
       // variables to substitute.
       return executable.getParameters().stream()
           .collect(toImmutableMap(v -> v.getSimpleName().toString(), Element::asType));
     }
     Map<Equivalence.Wrapper<TypeVariable>, TypeMirror> typeVariables = new LinkedHashMap<>();
     for (int i = 0; i < executableTypeParams.size(); i++) {
       TypeVariable from = MoreTypes.asTypeVariable(executableTypeParams.get(i).asType());
       TypeVariable to = MoreTypes.asTypeVariable(builderTypeParams.get(i).asType());
       typeVariables.put(MoreTypes.equivalence().wrap(from), to);
     }
     Function<TypeVariable, TypeMirror> substitute =
         v -> typeVariables.get(MoreTypes.equivalence().wrap(v));
     return executable.getParameters().stream()
         .collect(
             toImmutableMap(
                 v -> v.getSimpleName().toString(),
                 v -> TypeVariables.substituteTypeVariables(v.asType(), substitute, typeUtils)));
   }

   private static ImmutableList<TypeParameterElement> executableTypeParams(
       ExecutableElement executable) {
     switch (executable.getKind()) {
       case CONSTRUCTOR:
         // A constructor can have its own type parameters, in addition to any that its containing
         // class has. That's pretty unusual, but we allow it, requiring the builder to have type
         // parameters that are the concatenation of the class's and the constructor's.
         TypeElement container = MoreElements.asType(executable.getEnclosingElement());
         return ImmutableList.<TypeParameterElement>builder()
             .addAll(container.getTypeParameters())
             .addAll(executable.getTypeParameters())
             .build();
       case METHOD:
         return ImmutableList.copyOf(executable.getTypeParameters());
       default:
         throw new VerifyException("Unexpected executable kind " + executable.getKind());
     }
   }

   @Override
   Optional<String> propertyForBuilderGetter(ExecutableElement method) {
     String methodName = method.getSimpleName().toString();
     if (paramToPropertyName.containsValue(methodName)) {
       return Optional.of(methodName);
     }
     if (AutoValueishProcessor.isPrefixedGetter(method)) {
       int prefixLength = methodName.startsWith("get") ? 3 : 2; // "get" or "is"
       String unprefixed = methodName.substring(prefixLength);
       String propertyName = PropertyNames.decapitalizeLikeJavaBeans(unprefixed);
       if (paramToPropertyName.containsValue(propertyName)) {
         return Optional.of(propertyName);
       }
       propertyName = PropertyNames.decapitalizeNormally(unprefixed);
       if (paramToPropertyName.containsValue(propertyName)) {
         return Optional.of(propertyName);
       }
     }
     return Optional.empty();
   }

   @Override
   void checkForFailedJavaBean(ExecutableElement rejectedSetter) {}

   @Override
   ImmutableBiMap<String, VariableElement> propertyElements() {
     return paramToPropertyName.inverse();
   }

   @Override
   TypeMirror originalPropertyType(VariableElement propertyElement) {
     return propertyElement.asType();
   }

   @Override
   String propertyString(VariableElement propertyElement) {
     return "parameter \""
         + propertyElement.getSimpleName()
         + "\" of "
         + AutoBuilderProcessor.executableString(executable);
   }

   @Override
   String autoWhat() {
     return "AutoBuilder";
   }

   @Override
   String getterMustMatch() {
     return "a parameter of " + AutoBuilderProcessor.executableString(executable);
   }

   @Override
   String fooBuilderMustMatch() {
     return "foo";
   }
 }
	/*
	* Copyright 2021 Google LLC
	*
	* 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.
	*/
	package com.google.auto.value.processor;

	import static com.google.auto.common.MoreStreams.toImmutableBiMap;
	import static com.google.auto.common.MoreStreams.toImmutableMap;

	import com.google.auto.common.MoreElements;
	import com.google.auto.common.MoreTypes;
	import com.google.common.base.Equivalence;
	import com.google.common.base.VerifyException;
	import com.google.common.collect.ImmutableBiMap;
	import com.google.common.collect.ImmutableList;
	import com.google.common.collect.ImmutableMap;
	import java.util.LinkedHashMap;
	import java.util.List;
	import java.util.Map;
	import java.util.Optional;
	import java.util.function.Function;
	import javax.annotation.processing.ProcessingEnvironment;
	import javax.lang.model.element.Element;
	import javax.lang.model.element.ExecutableElement;
	import javax.lang.model.element.TypeElement;
	import javax.lang.model.element.TypeParameterElement;
	import javax.lang.model.element.VariableElement;
	import javax.lang.model.type.TypeMirror;
	import javax.lang.model.type.TypeVariable;
	import javax.lang.model.util.Types;

	class BuilderMethodClassifierForAutoBuilder extends BuilderMethodClassifier<VariableElement> {
	private final ExecutableElement executable;
	private final ImmutableBiMap<VariableElement, String> paramToPropertyName;

	private BuilderMethodClassifierForAutoBuilder(
	ErrorReporter errorReporter,
	ProcessingEnvironment processingEnv,
	ExecutableElement executable,
	TypeMirror builtType,
	TypeElement builderType,
	ImmutableBiMap<VariableElement, String> paramToPropertyName,
	ImmutableMap<String, TypeMirror> rewrittenPropertyTypes) {
	super(errorReporter, processingEnv, builtType, builderType, rewrittenPropertyTypes);
	this.executable = executable;
	this.paramToPropertyName = paramToPropertyName;
	}

	/**
	* Classifies the given methods from a builder type and its ancestors.
	*
	* @param methods the abstract methods in {@code builderType} and its ancestors.
	* @param errorReporter where to report errors.
	* @param processingEnv the ProcessingEnvironment for annotation processing.
	* @param executable the constructor or static method that AutoBuilder will call.
	* @param builtType the type to be built.
	* @param builderType the builder class or interface within {@code ofClass}.
	* @return an {@code Optional} that contains the results of the classification if it was
	* successful or nothing if it was not.
	*/
	static Optional<BuilderMethodClassifier<VariableElement>> classify(
	Iterable<ExecutableElement> methods,
	ErrorReporter errorReporter,
	ProcessingEnvironment processingEnv,
	ExecutableElement executable,
	TypeMirror builtType,
	TypeElement builderType) {
	ImmutableBiMap<VariableElement, String> paramToPropertyName =
	executable.getParameters().stream()
	.collect(toImmutableBiMap(v -> v, v -> v.getSimpleName().toString()));
	ImmutableMap<String, TypeMirror> rewrittenPropertyTypes =
	rewriteParameterTypes(executable, builderType, errorReporter, processingEnv.getTypeUtils());
	BuilderMethodClassifier<VariableElement> classifier =
	new BuilderMethodClassifierForAutoBuilder(
	errorReporter,
	processingEnv,
	executable,
	builtType,
	builderType,
	paramToPropertyName,
	rewrittenPropertyTypes);
	if (classifier.classifyMethods(methods, false)) {
	return Optional.of(classifier);
	} else {
	return Optional.empty();
	}
	}

	// Rewrites the parameter types of the executable so they use the type variables of the builder
	// where appropriate.
	//
	// Suppose we have something like this:
	//
	// static <E> Set<E> singletonSet(E elem) {...}
	//
	// @AutoBuilder(callMethod = "singletonSet")
	// interface SingletonSetBuilder<E> {
	// SingletonSetBuilder<E> setElem(E elem);
	// Set<E> build();
	// }
	//
	// We want to check that the type of the setter `setElem` matches the type of the
	// parameter it is setting. But in fact it doesn't: the type of the setter is
	// E-of-SingletonSetBuilder while the type of the parameter is E-of-singletonSet. So we
	// need to rewrite any type variables mentioned in parameters so that they use the corresponding
	// types from the builder. We want to return a map where "elem" is mapped to
	// E-of-SingletonSetBuilder, even though the `elem` that we get from the parameters of
	// singletonSet is going to be E-of-singletonSet. And we also want that to work if the parameter
	// is something more complicated, like List<? extends E>.
	//
	// For the corresponding situation with AutoValue, we have a way of dodging the problem somewhat.
	// For an @AutoValue class Foo<E> with a builder Builder<E>, we can craft a DeclaredType
	// Foo<E> where the E comes from Builder<E>, and we can use Types.asMemberOf to determine the
	// return types of methods (which are what we want to rewrite in that case). But that doesn't
	// work here because singletonSet is static and Types.asMemberOf would have no effect on it.
	//
	// So instead we take the type of each parameter and feed it through a TypeVisitor that rewrites
	// type variables, rewriting from E-of-singletonSet to E-of-SingletonSetBuilder. Then we can use
	// Types.isSameType or Types.isAssignable and it will work as we expect.
	//
	// In principle a similar situation arises with the return type Set<E> of singletonSet versus
	// the return type Set<E> of SingletonSetBuilder.build(). But in fact we only use
	// MoreTypes.equivalence to compare those, and that returns true for distinct type variables if
	// they have the same name and bounds.
	private static ImmutableMap<String, TypeMirror> rewriteParameterTypes(
	ExecutableElement executable,
	TypeElement builderType,
	ErrorReporter errorReporter,
	Types typeUtils) {
	ImmutableList<TypeParameterElement> executableTypeParams = executableTypeParams(executable);
	List<? extends TypeParameterElement> builderTypeParams = builderType.getTypeParameters();
	if (!BuilderSpec.sameTypeParameters(executableTypeParams, builderTypeParams)) {
	errorReporter.abortWithError(
	builderType,
	"[AutoBuilderTypeParams] Builder type parameters %s must match type parameters %s of %s",
	TypeEncoder.typeParametersString(builderTypeParams),
	TypeEncoder.typeParametersString(executableTypeParams),
	AutoBuilderProcessor.executableString(executable));
	}
	if (executableTypeParams.isEmpty()) {
	// Optimization for a common case. No point in doing all that type visiting if we have no
	// variables to substitute.
	return executable.getParameters().stream()
	.collect(toImmutableMap(v -> v.getSimpleName().toString(), Element::asType));
	}
	Map<Equivalence.Wrapper<TypeVariable>, TypeMirror> typeVariables = new LinkedHashMap<>();
	for (int i = 0; i < executableTypeParams.size(); i++) {
	TypeVariable from = MoreTypes.asTypeVariable(executableTypeParams.get(i).asType());
	TypeVariable to = MoreTypes.asTypeVariable(builderTypeParams.get(i).asType());
	typeVariables.put(MoreTypes.equivalence().wrap(from), to);
	}
	Function<TypeVariable, TypeMirror> substitute =
	v -> typeVariables.get(MoreTypes.equivalence().wrap(v));
	return executable.getParameters().stream()
	.collect(
	toImmutableMap(
	v -> v.getSimpleName().toString(),
	v -> TypeVariables.substituteTypeVariables(v.asType(), substitute, typeUtils)));
	}

	private static ImmutableList<TypeParameterElement> executableTypeParams(
	ExecutableElement executable) {
	switch (executable.getKind()) {
	case CONSTRUCTOR:
	// A constructor can have its own type parameters, in addition to any that its containing
	// class has. That's pretty unusual, but we allow it, requiring the builder to have type
	// parameters that are the concatenation of the class's and the constructor's.
	TypeElement container = MoreElements.asType(executable.getEnclosingElement());
	return ImmutableList.<TypeParameterElement>builder()
	.addAll(container.getTypeParameters())
	.addAll(executable.getTypeParameters())
	.build();
	case METHOD:
	return ImmutableList.copyOf(executable.getTypeParameters());
	default:
	throw new VerifyException("Unexpected executable kind " + executable.getKind());
	}
	}

	@Override
	Optional<String> propertyForBuilderGetter(ExecutableElement method) {
	String methodName = method.getSimpleName().toString();
	if (paramToPropertyName.containsValue(methodName)) {
	return Optional.of(methodName);
	}
	if (AutoValueishProcessor.isPrefixedGetter(method)) {
	int prefixLength = methodName.startsWith("get") ? 3 : 2; // "get" or "is"
	String unprefixed = methodName.substring(prefixLength);
	String propertyName = PropertyNames.decapitalizeLikeJavaBeans(unprefixed);
	if (paramToPropertyName.containsValue(propertyName)) {
	return Optional.of(propertyName);
	}
	propertyName = PropertyNames.decapitalizeNormally(unprefixed);
	if (paramToPropertyName.containsValue(propertyName)) {
	return Optional.of(propertyName);
	}
	}
	return Optional.empty();
	}

	@Override
	void checkForFailedJavaBean(ExecutableElement rejectedSetter) {}

	@Override
	ImmutableBiMap<String, VariableElement> propertyElements() {
	return paramToPropertyName.inverse();
	}

	@Override
	TypeMirror originalPropertyType(VariableElement propertyElement) {
	return propertyElement.asType();
	}

	@Override
	String propertyString(VariableElement propertyElement) {
	return "parameter \""
	+ propertyElement.getSimpleName()
	+ "\" of "
	+ AutoBuilderProcessor.executableString(executable);
	}

	@Override
	String autoWhat() {
	return "AutoBuilder";
	}

	@Override
	String getterMustMatch() {
	return "a parameter of " + AutoBuilderProcessor.executableString(executable);
	}

	@Override
	String fooBuilderMustMatch() {
	return "foo";
	}
	}