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      1 /*
      2  * Copyright (C) 2015 Google, Inc.
      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 package dagger.internal.codegen;
     17 
     18 import com.google.auto.common.MoreTypes;
     19 import com.google.common.collect.ImmutableMap;
     20 import com.google.common.collect.Maps;
     21 import com.google.common.collect.Sets;
     22 import dagger.internal.codegen.ComponentDescriptor.BuilderSpec;
     23 import dagger.internal.codegen.ComponentDescriptor.ComponentMethodDescriptor;
     24 import java.util.Map;
     25 import javax.lang.model.element.ExecutableElement;
     26 import javax.lang.model.element.TypeElement;
     27 import javax.lang.model.element.VariableElement;
     28 
     29 import static com.google.common.base.Functions.constant;
     30 
     31 /**
     32  * Validates the relationships between parent components and subcomponents.
     33  */
     34 final class ComponentHierarchyValidator {
     35   ValidationReport<TypeElement> validate(ComponentDescriptor componentDescriptor) {
     36     return validateSubcomponentMethods(
     37         componentDescriptor,
     38         Maps.toMap(
     39             componentDescriptor.transitiveModuleTypes(),
     40             constant(componentDescriptor.componentDefinitionType())));
     41   }
     42 
     43   private ValidationReport<TypeElement> validateSubcomponentMethods(
     44       ComponentDescriptor componentDescriptor,
     45       Map<TypeElement, TypeElement> existingModuleToOwners) {
     46     ValidationReport.Builder<TypeElement> reportBuilder =
     47         ValidationReport.about(componentDescriptor.componentDefinitionType());
     48     for (Map.Entry<ComponentMethodDescriptor, ComponentDescriptor> subcomponentEntry :
     49         componentDescriptor.subcomponents().entrySet()) {
     50       ComponentMethodDescriptor subcomponentMethodDescriptor = subcomponentEntry.getKey();
     51       ComponentDescriptor subcomponentDescriptor = subcomponentEntry.getValue();
     52       // validate the way that we create subcomponents
     53       switch (subcomponentMethodDescriptor.kind()) {
     54         case SUBCOMPONENT:
     55           for (VariableElement factoryMethodParameter :
     56               subcomponentMethodDescriptor.methodElement().getParameters()) {
     57             TypeElement origininatingComponent =
     58                 existingModuleToOwners.get(
     59                     MoreTypes.asTypeElement(factoryMethodParameter.asType()));
     60             if (origininatingComponent != null) {
     61               /* Factory method tries to pass a module that is already present in the parent.
     62                * This is an error. */
     63               reportBuilder.addError(
     64                   String.format(
     65                       "This module is present in %s. Subcomponents cannot use an instance of a "
     66                           + "module that differs from its parent.",
     67                       origininatingComponent.getQualifiedName()),
     68                   factoryMethodParameter);
     69             }
     70           }
     71           break;
     72         case SUBCOMPONENT_BUILDER:
     73           BuilderSpec subcomponentBuilderSpec = subcomponentDescriptor.builderSpec().get();
     74           for (Map.Entry<TypeElement, ExecutableElement> builderMethodEntry :
     75               subcomponentBuilderSpec.methodMap().entrySet()) {
     76             TypeElement origininatingComponent =
     77                 existingModuleToOwners.get(builderMethodEntry.getKey());
     78             if (origininatingComponent != null) {
     79               /* A subcomponent builder allows you to pass a module that is already present in the
     80                * parent.  This can't be an error because it might be valid in _other_ components, so
     81                * we warn here. */
     82               ExecutableElement builderMethodElement = builderMethodEntry.getValue();
     83               /* TODO(gak): consider putting this on the builder method directly if it's in the
     84                * component being compiled */
     85               reportBuilder.addWarning(
     86                   String.format(
     87                       "This module is present in %s. Subcomponents cannot use an instance of a "
     88                           + "module that differs from its parent. The implementation of %s "
     89                           + "in this component will throw %s.",
     90                       origininatingComponent.getQualifiedName(),
     91                       builderMethodElement.getSimpleName(),
     92                       UnsupportedOperationException.class.getSimpleName()),
     93                   builderMethodElement);
     94             }
     95           }
     96           break;
     97         default:
     98           throw new AssertionError();
     99       }
    100       reportBuilder.addSubreport(
    101           validateSubcomponentMethods(
    102               subcomponentDescriptor,
    103               new ImmutableMap.Builder<TypeElement, TypeElement>()
    104                   .putAll(existingModuleToOwners)
    105                   .putAll(
    106                       Maps.toMap(
    107                           Sets.difference(
    108                               subcomponentDescriptor.transitiveModuleTypes(),
    109                               existingModuleToOwners.keySet()),
    110                           constant(subcomponentDescriptor.componentDefinitionType())))
    111                   .build()));
    112     }
    113     return reportBuilder.build();
    114   }
    115 }
    116