1 /* 2 * Copyright (C) 2020 The Dagger Authors. 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 package dagger.internal.codegen; 18 19 import static com.google.auto.common.MoreElements.isAnnotationPresent; 20 import static dagger.internal.codegen.langmodel.DaggerElements.closestEnclosingTypeElement; 21 22 import com.google.auto.common.MoreElements; 23 import com.google.common.collect.ImmutableSet; 24 import dagger.assisted.Assisted; 25 import dagger.assisted.AssistedInject; 26 import dagger.internal.codegen.binding.AssistedInjectionAnnotations; 27 import dagger.internal.codegen.binding.InjectionAnnotations; 28 import dagger.internal.codegen.kotlin.KotlinMetadataUtil; 29 import dagger.internal.codegen.langmodel.DaggerElements; 30 import dagger.internal.codegen.langmodel.DaggerTypes; 31 import dagger.internal.codegen.validation.TypeCheckingProcessingStep; 32 import dagger.internal.codegen.validation.ValidationReport; 33 import java.lang.annotation.Annotation; 34 import javax.annotation.processing.Messager; 35 import javax.inject.Inject; 36 import javax.lang.model.element.Element; 37 import javax.lang.model.element.ElementKind; 38 import javax.lang.model.element.TypeElement; 39 import javax.lang.model.element.VariableElement; 40 41 /** 42 * An annotation processor for {@link dagger.assisted.Assisted}-annotated types. 43 * 44 * <p>This processing step should run after {@link AssistedFactoryProcessingStep}. 45 */ 46 final class AssistedProcessingStep extends TypeCheckingProcessingStep<VariableElement> { 47 private final KotlinMetadataUtil kotlinMetadataUtil; 48 private final InjectionAnnotations injectionAnnotations; 49 private final DaggerElements elements; 50 private final DaggerTypes types; 51 private final Messager messager; 52 53 @Inject AssistedProcessingStep( KotlinMetadataUtil kotlinMetadataUtil, InjectionAnnotations injectionAnnotations, DaggerElements elements, DaggerTypes types, Messager messager)54 AssistedProcessingStep( 55 KotlinMetadataUtil kotlinMetadataUtil, 56 InjectionAnnotations injectionAnnotations, 57 DaggerElements elements, 58 DaggerTypes types, 59 Messager messager) { 60 super(MoreElements::asVariable); 61 this.kotlinMetadataUtil = kotlinMetadataUtil; 62 this.injectionAnnotations = injectionAnnotations; 63 this.elements = elements; 64 this.types = types; 65 this.messager = messager; 66 } 67 68 @Override annotations()69 public ImmutableSet<Class<? extends Annotation>> annotations() { 70 return ImmutableSet.of(Assisted.class); 71 } 72 73 @Override process( VariableElement assisted, ImmutableSet<Class<? extends Annotation>> annotations)74 protected void process( 75 VariableElement assisted, ImmutableSet<Class<? extends Annotation>> annotations) { 76 new AssistedValidator().validate(assisted).printMessagesTo(messager); 77 } 78 79 private final class AssistedValidator { validate(VariableElement assisted)80 ValidationReport<VariableElement> validate(VariableElement assisted) { 81 ValidationReport.Builder<VariableElement> report = ValidationReport.about(assisted); 82 83 Element enclosingElement = assisted.getEnclosingElement(); 84 if (!isAssistedInjectConstructor(enclosingElement) 85 && !isAssistedFactoryCreateMethod(enclosingElement) 86 // The generated java stubs for kotlin data classes contain a "copy" method that has 87 // the same parameters (and annotations) as the constructor, so just ignore it. 88 && !isKotlinDataClassCopyMethod(enclosingElement)) { 89 report.addError( 90 "@Assisted parameters can only be used within an @AssistedInject-annotated " 91 + "constructor.", 92 assisted); 93 } 94 95 injectionAnnotations 96 .getQualifiers(assisted) 97 .forEach( 98 qualifier -> 99 report.addError( 100 "Qualifiers cannot be used with @Assisted parameters.", assisted, qualifier)); 101 102 return report.build(); 103 } 104 } 105 isAssistedInjectConstructor(Element element)106 private boolean isAssistedInjectConstructor(Element element) { 107 return element.getKind() == ElementKind.CONSTRUCTOR 108 && isAnnotationPresent(element, AssistedInject.class); 109 } 110 isAssistedFactoryCreateMethod(Element element)111 private boolean isAssistedFactoryCreateMethod(Element element) { 112 if (element.getKind() == ElementKind.METHOD) { 113 TypeElement enclosingElement = closestEnclosingTypeElement(element); 114 return AssistedInjectionAnnotations.isAssistedFactoryType(enclosingElement) 115 // This assumes we've already validated AssistedFactory and that a valid method exists. 116 && AssistedInjectionAnnotations.assistedFactoryMethod(enclosingElement, elements, types) 117 .equals(element); 118 } 119 return false; 120 } 121 isKotlinDataClassCopyMethod(Element element)122 private boolean isKotlinDataClassCopyMethod(Element element) { 123 // Note: This is a best effort. Technically, we could check the return type and parameters of 124 // the copy method to verify it's the one associated with the constructor, but I'd rather keep 125 // this simple to avoid encoding too many details of kapt's stubs. At worst, we'll be allowing 126 // an @Assisted annotation that has no affect, which is already true for many of Dagger's other 127 // annotations. 128 return element.getKind() == ElementKind.METHOD 129 && element.getSimpleName().contentEquals("copy") 130 && kotlinMetadataUtil.isDataClass(closestEnclosingTypeElement(element)); 131 } 132 } 133