java/dagger/internal/codegen/MembersInjectionMethods.java

/*
 * Copyright (C) 2017 The Dagger Authors.
 *
 * 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 dagger.internal.codegen;

import static com.google.common.base.MoreObjects.firstNonNull;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.squareup.javapoet.MethodSpec.methodBuilder;
import static dagger.internal.codegen.Accessibility.isTypeAccessibleFrom;
import static dagger.internal.codegen.Util.reentrantComputeIfAbsent;
import static javax.lang.model.element.Modifier.PRIVATE;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.squareup.javapoet.ClassName;
import com.squareup.javapoet.CodeBlock;
import com.squareup.javapoet.MethodSpec;
import com.squareup.javapoet.ParameterSpec;
import com.squareup.javapoet.TypeName;
import dagger.internal.codegen.InjectionMethods.InjectionSiteMethod;
import dagger.internal.codegen.MembersInjectionBinding.InjectionSite;
import java.util.LinkedHashMap;
import java.util.Map;
import javax.lang.model.element.Name;
import javax.lang.model.element.TypeElement;
import javax.lang.model.type.TypeMirror;
import javax.lang.model.util.Elements;

/** Manages the member injection methods for a component. */
final class MembersInjectionMethods {
  private final Map<Key, MethodSpec> membersInjectionMethods = new LinkedHashMap<>();
  private final GeneratedComponentModel generatedComponentModel;
  private final ComponentBindingExpressions bindingExpressions;
  private final BindingGraph graph;
  private final Elements elements;
  private final DaggerTypes types;

  MembersInjectionMethods(
      GeneratedComponentModel generatedComponentModel,
      ComponentBindingExpressions bindingExpressions,
      BindingGraph graph,
      Elements elements,
      DaggerTypes types) {
    this.generatedComponentModel = checkNotNull(generatedComponentModel);
    this.bindingExpressions = checkNotNull(bindingExpressions);
    this.graph = checkNotNull(graph);
    this.elements = checkNotNull(elements);
    this.types = checkNotNull(types);
  }

  /**
   * Returns the members injection {@link MethodSpec} for the given {@link Key}, creating it if
   * necessary.
   *
   * <p>To get a list of all members injection {@link MethodSpec}s, call {@link #getAllMethods()}
   */
  MethodSpec getOrCreate(Key key) {
    return reentrantComputeIfAbsent(membersInjectionMethods, key, this::membersInjectionMethod);
  }

  /** Returns the list of all members injection {@link MethodSpec}s for this component. */
  ImmutableList<MethodSpec> getAllMethods() {
    return ImmutableList.copyOf(membersInjectionMethods.values());
  }

  private MethodSpec membersInjectionMethod(Key key) {
    Binding binding =
        firstNonNull(
                graph.resolvedBindings().get(BindingKey.membersInjection(key)),
                graph.resolvedBindings().get(BindingKey.contribution(key)))
            .binding();
    TypeMirror keyType = binding.key().type();
    TypeMirror membersInjectedType =
        isTypeAccessibleFrom(keyType, generatedComponentModel.name().packageName())
            ? keyType
            : elements.getTypeElement("java.lang.Object").asType();
    TypeName membersInjectedTypeName = TypeName.get(membersInjectedType);
    Name bindingTypeName = binding.bindingTypeElement().get().getSimpleName();
    // TODO(ronshapiro): include type parameters in this name e.g. injectFooOfT, and outer class
    // simple names Foo.Builder -> injectFooBuilder
    String methodName = generatedComponentModel.getUniqueMethodName("inject" + bindingTypeName);
    ParameterSpec parameter = ParameterSpec.builder(membersInjectedTypeName, "instance").build();
    MethodSpec.Builder method =
        methodBuilder(methodName)
            .addModifiers(PRIVATE)
            .returns(membersInjectedTypeName)
            .addParameter(parameter);
    TypeElement canIgnoreReturnValue =
        elements.getTypeElement("com.google.errorprone.annotations.CanIgnoreReturnValue");
    if (canIgnoreReturnValue != null) {
      method.addAnnotation(ClassName.get(canIgnoreReturnValue));
    }
    CodeBlock instance = CodeBlock.of("$N", parameter);
    method.addCode(
        InjectionSiteMethod.invokeAll(
            injectionSites(binding),
            generatedComponentModel.name(),
            instance,
            membersInjectedType,
            types,
            request ->
                bindingExpressions
                    .getDependencyArgumentExpression(request, generatedComponentModel.name())
                    .codeBlock()));
    method.addStatement("return $L", instance);

    return method.build();
  }

  private static ImmutableSet<InjectionSite> injectionSites(Binding binding) {
    if (binding instanceof ProvisionBinding) {
      return ((ProvisionBinding) binding).injectionSites();
    } else if (binding instanceof MembersInjectionBinding) {
      return ((MembersInjectionBinding) binding).injectionSites();
    }
    throw new IllegalArgumentException(binding.key().toString());
  }
}