java/dagger/internal/codegen/SimpleMethodBindingExpression.java

/*
 * Copyright (C) 2016 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.auto.common.MoreElements.asExecutable;
import static com.google.common.base.Preconditions.checkArgument;
import static dagger.internal.codegen.Accessibility.isTypeAccessibleFrom;
import static dagger.internal.codegen.CodeBlocks.toParametersCodeBlock;
import static dagger.internal.codegen.InjectionMethods.ProvisionMethod.requiresInjectionMethod;
import static dagger.internal.codegen.TypeNames.rawTypeName;

import com.google.auto.common.MoreTypes;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Maps;
import com.squareup.javapoet.ClassName;
import com.squareup.javapoet.CodeBlock;
import com.squareup.javapoet.MethodSpec;
import com.squareup.javapoet.TypeName;
import dagger.internal.codegen.InjectionMethods.ProvisionMethod;
import dagger.model.DependencyRequest;
import java.util.Optional;
import java.util.function.Function;
import javax.lang.model.element.Element;
import javax.lang.model.element.ExecutableElement;
import javax.lang.model.type.DeclaredType;
import javax.lang.model.type.TypeMirror;

/**
 * A binding expression that invokes methods or constructors directly (without attempting to scope)
 * {@link dagger.model.RequestKind#INSTANCE} requests.
 */
final class SimpleMethodBindingExpression extends SimpleInvocationBindingExpression {
  private final CompilerOptions compilerOptions;
  private final ProvisionBinding provisionBinding;
  private final ComponentBindingExpressions componentBindingExpressions;
  private final MembersInjectionMethods membersInjectionMethods;
  private final ComponentRequirementExpressions componentRequirementExpressions;
  private final DaggerTypes types;
  private final DaggerElements elements;

  SimpleMethodBindingExpression(
      ResolvedBindings resolvedBindings,
      CompilerOptions compilerOptions,
      ComponentBindingExpressions componentBindingExpressions,
      MembersInjectionMethods membersInjectionMethods,
      ComponentRequirementExpressions componentRequirementExpressions,
      DaggerTypes types,
      DaggerElements elements) {
    super(resolvedBindings);
    this.compilerOptions = compilerOptions;
    this.provisionBinding = (ProvisionBinding) resolvedBindings.contributionBinding();
    checkArgument(
        provisionBinding.implicitDependencies().isEmpty(),
        "framework deps are not currently supported");
    checkArgument(provisionBinding.bindingElement().isPresent());
    this.componentBindingExpressions = componentBindingExpressions;
    this.membersInjectionMethods = membersInjectionMethods;
    this.componentRequirementExpressions = componentRequirementExpressions;
    this.types = types;
    this.elements = elements;
  }

  @Override
  Expression getDependencyExpression(ClassName requestingClass) {
    ImmutableMap<DependencyRequest, Expression> arguments =
        ImmutableMap.copyOf(
            Maps.asMap(
                provisionBinding.dependencies(),
                request -> dependencyArgument(request, requestingClass)));
    Function<DependencyRequest, CodeBlock> argumentsFunction =
        request -> arguments.get(request).codeBlock();
    return requiresInjectionMethod(
            provisionBinding,
            arguments.values().asList(),
            compilerOptions,
            requestingClass.packageName(),
            types)
        ? invokeInjectionMethod(argumentsFunction, requestingClass)
        : invokeMethod(argumentsFunction, requestingClass);
  }

  private Expression invokeMethod(
      Function<DependencyRequest, CodeBlock> argumentsFunction,
      ClassName requestingClass) {
    // TODO(dpb): align this with the contents of InlineMethods.create
    CodeBlock arguments =
        provisionBinding.dependencies().stream()
            .map(argumentsFunction)
            .collect(toParametersCodeBlock());
    ExecutableElement method = asExecutable(provisionBinding.bindingElement().get());
    CodeBlock invocation;
    switch (method.getKind()) {
      case CONSTRUCTOR:
        invocation = CodeBlock.of("new $T($L)", constructorTypeName(requestingClass), arguments);
        break;
      case METHOD:
        CodeBlock module =
            moduleReference(requestingClass)
                .orElse(CodeBlock.of("$T", provisionBinding.bindingTypeElement().get()));
        invocation = CodeBlock.of("$L.$L($L)", module, method.getSimpleName(), arguments);
        break;
      default:
        throw new IllegalStateException();
    }

    return Expression.create(simpleMethodReturnType(), invocation);
  }

  private TypeName constructorTypeName(ClassName requestingClass) {
    DeclaredType type = MoreTypes.asDeclared(provisionBinding.key().type());
    TypeName typeName = TypeName.get(type);
    if (type.getTypeArguments()
        .stream()
        .allMatch(t -> isTypeAccessibleFrom(t, requestingClass.packageName()))) {
      return typeName;
    }
    return rawTypeName(typeName);
  }

  private Expression invokeInjectionMethod(
      Function<DependencyRequest, CodeBlock> argumentsFunction, ClassName requestingClass) {
    return injectMembers(
        ProvisionMethod.invoke(
            provisionBinding,
            argumentsFunction,
            requestingClass,
            moduleReference(requestingClass),
            compilerOptions,
            elements));
  }

  private Expression dependencyArgument(DependencyRequest dependency, ClassName requestingClass) {
    return componentBindingExpressions.getDependencyArgumentExpression(dependency, requestingClass);
  }

  private Expression injectMembers(CodeBlock instance) {
    if (provisionBinding.injectionSites().isEmpty()) {
      return Expression.create(simpleMethodReturnType(), instance);
    }
    // Java 7 type inference can't figure out that instance in
    // injectParameterized(Parameterized_Factory.newParameterized()) is Parameterized<T> and not
    // Parameterized<Object>
    if (!MoreTypes.asDeclared(provisionBinding.key().type()).getTypeArguments().isEmpty()) {
      TypeName keyType = TypeName.get(provisionBinding.key().type());
      instance = CodeBlock.of("($T) ($T) $L", keyType, rawTypeName(keyType), instance);
    }

    MethodSpec membersInjectionMethod = membersInjectionMethods.getOrCreate(provisionBinding.key());
    TypeMirror returnType =
        membersInjectionMethod.returnType.equals(TypeName.OBJECT)
            ? elements.getTypeElement(Object.class).asType()
            : provisionBinding.key().type();
    return Expression.create(returnType, CodeBlock.of("$N($L)", membersInjectionMethod, instance));
  }

  private Optional<CodeBlock> moduleReference(ClassName requestingClass) {
    return provisionBinding.requiresModuleInstance()
        ? provisionBinding
            .contributingModule()
            .map(Element::asType)
            .map(ComponentRequirement::forModule)
            .map(module -> componentRequirementExpressions.getExpression(module, requestingClass))
        : Optional.empty();
  }

  private TypeMirror simpleMethodReturnType() {
    return provisionBinding.contributedPrimitiveType().orElse(provisionBinding.key().type());
  }
}