Reorganized rootcomponentgenerator package and added demo.

-Moved rootcomponentgenerator/annotations to dialer/inject to reduce the number of deps engineers need to include

-Move rootcomponentgenerator/processor into rootcomponentgenerator/ since the other package is now gone

-Added inject/demo and tests

TEST=unit, tap
Test: unit, tap
PiperOrigin-RevId: 191916595
Change-Id: Ic155808c7435bdce198970caa92309edb9fadac8

1 files changed, 267 insertions, 0 deletions

diff --git a/java/com/android/dialer/rootcomponentgenerator/ComponentGeneratingStep.java b/java/com/android/dialer/rootcomponentgenerator/ComponentGeneratingStep.java
new file mode 100644
index 000000000..1a40611c5
--- /dev/null
+++ b/java/com/android/dialer/rootcomponentgenerator/ComponentGeneratingStep.java
@@ -0,0 +1,267 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * 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.android.dialer.rootcomponentgenerator;
+
+import static com.google.auto.common.AnnotationMirrors.getAnnotationValue;
+import static com.google.auto.common.MoreElements.getAnnotationMirror;
+import static javax.lang.model.element.Modifier.ABSTRACT;
+import static javax.lang.model.element.Modifier.PUBLIC;
+import static javax.lang.model.element.Modifier.STATIC;
+import static javax.lang.model.util.ElementFilter.typesIn;
+
+import com.android.dialer.inject.IncludeInDialerRoot;
+import com.google.auto.common.BasicAnnotationProcessor.ProcessingStep;
+import com.google.auto.common.MoreElements;
+import com.google.common.base.Optional;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.SetMultimap;
+import com.squareup.javapoet.AnnotationSpec;
+import com.squareup.javapoet.ClassName;
+import com.squareup.javapoet.FieldSpec;
+import com.squareup.javapoet.MethodSpec;
+import com.squareup.javapoet.ParameterSpec;
+import com.squareup.javapoet.TypeName;
+import com.squareup.javapoet.TypeSpec;
+import dagger.Subcomponent;
+import java.lang.annotation.Annotation;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Set;
+import javax.annotation.processing.ProcessingEnvironment;
+import javax.lang.model.element.AnnotationMirror;
+import javax.lang.model.element.AnnotationValue;
+import javax.lang.model.element.Element;
+import javax.lang.model.element.ExecutableElement;
+import javax.lang.model.element.TypeElement;
+import javax.lang.model.element.VariableElement;
+import javax.lang.model.type.TypeMirror;
+
+/**
+ * Generates component for a type annotated with {@link IncludeInDialerRoot}.
+ *
+ * <p>Our components have boilerplate code like:
+ *
+ * <p>
+ *
+ * <pre>
+ * <code>
+ *
+ * {@literal @}dagger.Subcomponent
+ * public abstract class GenXXXXComponent {
+ *   public static SimulatorComponent get(Context context) {
+ *      return ((HasComponent)((HasRootComponent) context.getApplicationContext()).component())
+ *         .simulatorComponent();
+ *   }
+ *   {@literal @}IncludeInDialerRoot
+ *   public interface HasComponent {
+ *      SimulatorComponent simulatorComponent();
+ *  }
+ * }
+ * </code>
+ * </pre>
+ */
+final class ComponentGeneratingStep implements ProcessingStep {
+
+  private static final String DIALER_INJECT_PACKAGE = "com.android.dialer.inject";
+  private static final String DIALER_HASROOTCOMPONENT_INTERFACE = "HasRootComponent";
+  private static final ClassName ANDROID_CONTEXT_CLASS_NAME =
+      ClassName.get("android.content", "Context");
+  private final ProcessingEnvironment processingEnv;
+
+  public ComponentGeneratingStep(ProcessingEnvironment processingEnv) {
+    this.processingEnv = processingEnv;
+  }
+
+  @Override
+  public Set<? extends Class<? extends Annotation>> annotations() {
+    return ImmutableSet.of(IncludeInDialerRoot.class);
+  }
+
+  @Override
+  public Set<? extends Element> process(
+      SetMultimap<Class<? extends Annotation>, Element> elementsByAnnotation) {
+    for (TypeElement type : typesIn(elementsByAnnotation.get(IncludeInDialerRoot.class))) {
+      generateComponent(type);
+    }
+    return Collections.emptySet();
+  }
+
+  /**
+   * Generates component file for a componentElement.
+   *
+   * <p>The annotation processor will generate a new type file with some prefix, which contains
+   * public static XXX get(Context context) method and HasComponent interface.
+   *
+   * @param dialerComponentElement a component used by the annotation processor.
+   */
+  private void generateComponent(TypeElement dialerComponentElement) {
+    TypeSpec.Builder componentClass =
+        dialerComponentElement.getKind().isClass()
+            ? cloneClass(dialerComponentElement, RootComponentUtils.GENERATED_COMPONENT_PREFIX)
+            : cloneInterface(dialerComponentElement, RootComponentUtils.GENERATED_COMPONENT_PREFIX);
+    componentClass.addAnnotation(makeDaggerSubcomponentAnnotation(dialerComponentElement));
+    RootComponentUtils.writeJavaFile(
+        processingEnv,
+        ClassName.get(dialerComponentElement).packageName(),
+        dialerBoilerplateCode(componentClass, dialerComponentElement));
+  }
+
+  @SuppressWarnings("unchecked")
+  private AnnotationSpec makeDaggerSubcomponentAnnotation(TypeElement dialerComponentElement) {
+
+    Optional<AnnotationMirror> componentMirror =
+        getAnnotationMirror(dialerComponentElement, IncludeInDialerRoot.class);
+
+    AnnotationSpec.Builder subcomponentBuilder = AnnotationSpec.builder(Subcomponent.class);
+    for (AnnotationValue annotationValue :
+        (List<? extends AnnotationValue>)
+            getAnnotationValue(componentMirror.get(), "modules").getValue()) {
+      subcomponentBuilder.addMember(
+          "modules", "$T.class", ClassName.get((TypeMirror) annotationValue.getValue()));
+    }
+    return subcomponentBuilder.build();
+  }
+
+  private TypeSpec dialerBoilerplateCode(
+      TypeSpec.Builder typeBuilder, TypeElement dialerComponentElement) {
+    return typeBuilder
+        .addType(hasComponentInterface(typeBuilder, dialerComponentElement))
+        .addMethod(addGetComponentMethod(typeBuilder, dialerComponentElement))
+        .build();
+  }
+
+  private TypeSpec hasComponentInterface(
+      TypeSpec.Builder typeBuilder, TypeElement dialerComponentElement) {
+    return TypeSpec.interfaceBuilder("HasComponent")
+        .addModifiers(PUBLIC)
+        .addMethod(
+            MethodSpec.methodBuilder("make" + dialerComponentElement.getSimpleName())
+                .addModifiers(PUBLIC, ABSTRACT)
+                .returns(getComponentClass(typeBuilder, dialerComponentElement))
+                .build())
+        .build();
+  }
+
+  private MethodSpec addGetComponentMethod(
+      TypeSpec.Builder typeBuilder, TypeElement dialerComponentElement) {
+    ClassName hasComponenetInterface =
+        ClassName.get(
+                getPackageName(dialerComponentElement),
+                RootComponentUtils.GENERATED_COMPONENT_PREFIX
+                    + dialerComponentElement.getSimpleName())
+            .nestedClass("HasComponent");
+    ClassName hasRootComponentInterface =
+        ClassName.get(DIALER_INJECT_PACKAGE, DIALER_HASROOTCOMPONENT_INTERFACE);
+    return MethodSpec.methodBuilder("get")
+        .addModifiers(PUBLIC, STATIC)
+        .addParameter(ParameterSpec.builder(ANDROID_CONTEXT_CLASS_NAME, "context").build())
+        .addStatement(
+            "$1T hasRootComponent = ($1T) context.getApplicationContext()",
+            hasRootComponentInterface)
+        .addStatement(
+            "return (($T) (hasRootComponent.component())).make$T()",
+            hasComponenetInterface,
+            dialerComponentElement)
+        .returns(getComponentClass(typeBuilder, dialerComponentElement))
+        .build();
+  }
+
+  private void addElement(TypeSpec.Builder builder, Element element) {
+    switch (element.getKind()) {
+      case INTERFACE:
+        builder.addType(cloneInterface(MoreElements.asType(element), "").build());
+        break;
+      case CLASS:
+        builder.addType(cloneClass(MoreElements.asType(element), "").build());
+        break;
+      case FIELD:
+        builder.addField(cloneField(MoreElements.asVariable(element)).build());
+        break;
+      case METHOD:
+        builder.addMethod(cloneMethod(MoreElements.asExecutable(element)));
+        break;
+      case CONSTRUCTOR:
+        builder.addMethod(cloneConstructor(MoreElements.asExecutable(element)));
+        break;
+      default:
+        throw new RuntimeException(
+            String.format("Unexpected element %s met during class cloning phase!", element));
+    }
+  }
+
+  private MethodSpec cloneMethod(ExecutableElement element) {
+    return MethodSpec.methodBuilder(element.getSimpleName().toString())
+        .addModifiers(element.getModifiers())
+        .returns(TypeName.get(element.getReturnType()))
+        .addParameters(cloneParameters(element.getParameters()))
+        .build();
+  }
+
+  private MethodSpec cloneConstructor(ExecutableElement element) {
+    return MethodSpec.constructorBuilder()
+        .addModifiers(element.getModifiers())
+        .addParameters(cloneParameters(element.getParameters()))
+        .build();
+  }
+
+  private List<ParameterSpec> cloneParameters(
+      List<? extends VariableElement> variableElementsList) {
+    List<ParameterSpec> list = new ArrayList<>();
+    for (VariableElement variableElement : variableElementsList) {
+      ParameterSpec.Builder builder =
+          ParameterSpec.builder(
+                  TypeName.get(variableElement.asType()),
+                  variableElement.getSimpleName().toString())
+              .addModifiers(variableElement.getModifiers());
+      list.add(builder.build());
+    }
+    return list;
+  }
+
+  private TypeSpec.Builder cloneInterface(TypeElement element, String prefix) {
+    return cloneType(TypeSpec.interfaceBuilder(prefix + element.getSimpleName()), element);
+  }
+
+  private TypeSpec.Builder cloneClass(TypeElement element, String prefix) {
+    return cloneType(TypeSpec.classBuilder(prefix + element.getSimpleName()), element);
+  }
+
+  private FieldSpec.Builder cloneField(VariableElement element) {
+    FieldSpec.Builder builder =
+        FieldSpec.builder(TypeName.get(element.asType()), element.getSimpleName().toString());
+    element.getModifiers().forEach(builder::addModifiers);
+    return builder;
+  }
+
+  private TypeSpec.Builder cloneType(TypeSpec.Builder builder, TypeElement element) {
+    element.getModifiers().forEach(builder::addModifiers);
+    for (Element enclosedElement : element.getEnclosedElements()) {
+      addElement(builder, enclosedElement);
+    }
+    return builder;
+  }
+
+  private ClassName getComponentClass(
+      TypeSpec.Builder typeBuilder, TypeElement dialerComponentElement) {
+    return ClassName.get(getPackageName(dialerComponentElement), typeBuilder.build().name);
+  }
+
+  private String getPackageName(TypeElement element) {
+    return ClassName.get(element).packageName();
+  }
+}