InspectionCompanions as nested classes

+ Generate inspection companions as MyClass$InspectionCompanion instead
  of MyClass$$InspectionCompanion. This allows the discovery of custom
  inspection companions written as nested classes.
+ Rename GeneratedInspectionCompanionProvider to
  StaticInspectionCompanionProvider to more clearly articulate how it
  function in the new world.
+ StaticInspectionCompanionProvider now explicitly checks if a class it
  discovered implements InspectionCompanion, and returns null instead of
  throwing a ClassCastException.
+ The annotation processor checks for the existence of a nested class
  named InspectionCompanion, and fails the build if a class has both a
  custom InspectionCompanion and @InspectableProperty annotations.

Test: atest --host view-inspector-annotation-processor-test
Bug: 126913705
Change-Id: Ic0d2100ec22420e36f9db44e56c66fe9146eeb0c

10 files changed, 36 insertions, 10 deletions

diff --git a/tools/processors/view_inspector/src/java/android/processor/view/inspector/InspectionCompanionGenerator.java b/tools/processors/view_inspector/src/java/android/processor/view/inspector/InspectionCompanionGenerator.java
index 44d88bb4b73d..6f6c1aa485ac 100644
--- a/tools/processors/view_inspector/src/java/android/processor/view/inspector/InspectionCompanionGenerator.java
+++ b/tools/processors/view_inspector/src/java/android/processor/view/inspector/InspectionCompanionGenerator.java
@@ -97,7 +97,7 @@ public final class InspectionCompanionGenerator {
     /**
      * The suffix of the generated class name after the class's binary name.
      */
-    private static final String GENERATED_CLASS_SUFFIX = "$$InspectionCompanion";
+    private static final String GENERATED_CLASS_SUFFIX = "$InspectionCompanion";
 
     /**
      * The null resource ID, copied to avoid a host dependency on platform code.
diff --git a/tools/processors/view_inspector/src/java/android/processor/view/inspector/PlatformInspectableProcessor.java b/tools/processors/view_inspector/src/java/android/processor/view/inspector/PlatformInspectableProcessor.java
index 01d94307f871..fd142c62e8e3 100644
--- a/tools/processors/view_inspector/src/java/android/processor/view/inspector/PlatformInspectableProcessor.java
+++ b/tools/processors/view_inspector/src/java/android/processor/view/inspector/PlatformInspectableProcessor.java
@@ -34,6 +34,7 @@ import javax.lang.model.element.Element;
 import javax.lang.model.element.ElementKind;
 import javax.lang.model.element.Modifier;
 import javax.lang.model.element.TypeElement;
+import javax.lang.model.util.ElementFilter;
 
 
 /**
@@ -127,13 +128,38 @@ public final class PlatformInspectableProcessor extends AbstractProcessor {
 
             final InspectableClassModel model = modelMap.computeIfAbsent(
                     classElement.get().getQualifiedName().toString(),
-                    k -> new InspectableClassModel(ClassName.get(classElement.get())));
+                    k -> {
+                        if (hasNestedInspectionCompanion(classElement.get())) {
+                            fail(
+                                    String.format(
+                                            "Class %s already has an inspection companion.",
+                                            classElement.get().getQualifiedName().toString()),
+                                    element);
+                        }
+                        return new InspectableClassModel(ClassName.get(classElement.get()));
+                    });
 
             processor.process(element, model);
         }
     }
 
     /**
+     * Determine if a class has a nested class named {@code InspectionCompanion}.
+     *
+     * @param typeElement A type element representing the class to check
+     * @return f the class contains a class named {@code InspectionCompanion}
+     */
+    private static boolean hasNestedInspectionCompanion(TypeElement typeElement) {
+        for (TypeElement nestedClass : ElementFilter.typesIn(typeElement.getEnclosedElements())) {
+            if (nestedClass.getSimpleName().toString().equals("InspectionCompanion")) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
      * Get the nearest enclosing class if there is one.
      *
      * If {@param element} represents a class, it will be returned wrapped in an optional.
diff --git a/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/FieldProperty.java.txt b/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/FieldProperty.java.txt
index a44c43ec0b21..9a0fe5b76e27 100644
--- a/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/FieldProperty.java.txt
+++ b/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/FieldProperty.java.txt
@@ -12,7 +12,7 @@ import java.lang.Override;
  * Generated by {@link android.processor.view.inspector.InspectionCompanionGenerator}
  * on behalf of {@link android.processor.view.inspector.InspectionCompanionGeneratorTest}.
  */
-public final class TestNode$$InspectionCompanion implements InspectionCompanion<TestNode> {
+public final class TestNode$InspectionCompanion implements InspectionCompanion<TestNode> {
     /**
      * Set by {@link #mapProperties(PropertyMapper)} once properties have been mapped.
      */
diff --git a/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/IntEnum.java.txt b/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/IntEnum.java.txt
index 764aa8bfbd63..b491de1d63ad 100644
--- a/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/IntEnum.java.txt
+++ b/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/IntEnum.java.txt
@@ -13,7 +13,7 @@ import java.lang.Override;
  * Generated by {@link android.processor.view.inspector.InspectionCompanionGenerator}
  * on behalf of {@link android.processor.view.inspector.InspectionCompanionGeneratorTest}.
  */
-public final class TestNode$$InspectionCompanion implements InspectionCompanion<TestNode> {
+public final class TestNode$InspectionCompanion implements InspectionCompanion<TestNode> {
     /**
      * Set by {@link #mapProperties(PropertyMapper)} once properties have been mapped.
      */
diff --git a/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/IntFlag.java.txt b/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/IntFlag.java.txt
index 75f281314965..7d180580b45e 100644
--- a/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/IntFlag.java.txt
+++ b/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/IntFlag.java.txt
@@ -12,7 +12,7 @@ import java.lang.Override;
  * Generated by {@link android.processor.view.inspector.InspectionCompanionGenerator}
  * on behalf of {@link android.processor.view.inspector.InspectionCompanionGeneratorTest}.
  */
-public final class TestNode$$InspectionCompanion implements InspectionCompanion<TestNode> {
+public final class TestNode$InspectionCompanion implements InspectionCompanion<TestNode> {
     /**
      * Set by {@link #mapProperties(PropertyMapper)} once properties have been mapped.
      */
diff --git a/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/NestedClass.java.txt b/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/NestedClass.java.txt
index 0cac462fba51..dc27abbe6fbd 100644
--- a/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/NestedClass.java.txt
+++ b/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/NestedClass.java.txt
@@ -11,7 +11,7 @@ import java.lang.Override;
  * Generated by {@link android.processor.view.inspector.InspectionCompanionGenerator}
  * on behalf of {@link android.processor.view.inspector.InspectionCompanionGeneratorTest}.
  */
-public final class Outer$Inner$$InspectionCompanion implements InspectionCompanion<Outer.Inner> {
+public final class Outer$Inner$InspectionCompanion implements InspectionCompanion<Outer.Inner> {
     /**
      * Set by {@link #mapProperties(PropertyMapper)} once properties have been mapped.
      */
diff --git a/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/NoAttributeId.java.txt b/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/NoAttributeId.java.txt
index ce0f867d5332..738bcd3dab36 100644
--- a/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/NoAttributeId.java.txt
+++ b/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/NoAttributeId.java.txt
@@ -11,7 +11,7 @@ import java.lang.Override;
  * Generated by {@link android.processor.view.inspector.InspectionCompanionGenerator}
  * on behalf of {@link android.processor.view.inspector.InspectionCompanionGeneratorTest}.
  */
-public final class TestNode$$InspectionCompanion implements InspectionCompanion<TestNode> {
+public final class TestNode$InspectionCompanion implements InspectionCompanion<TestNode> {
     /**
      * Set by {@link #mapProperties(PropertyMapper)} once properties have been mapped.
      */
diff --git a/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/NodeName.java.txt b/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/NodeName.java.txt
index f7357fece2bf..82dd66e2597e 100644
--- a/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/NodeName.java.txt
+++ b/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/NodeName.java.txt
@@ -12,7 +12,7 @@ import java.lang.String;
  * Generated by {@link android.processor.view.inspector.InspectionCompanionGenerator}
  * on behalf of {@link android.processor.view.inspector.InspectionCompanionGeneratorTest}.
  */
-public final class TestNode$$InspectionCompanion implements InspectionCompanion<TestNode> {
+public final class TestNode$InspectionCompanion implements InspectionCompanion<TestNode> {
     /**
      * Set by {@link #mapProperties(PropertyMapper)} once properties have been mapped.
      */
diff --git a/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/SimpleProperties.java.txt b/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/SimpleProperties.java.txt
index 556d8ddc5d5e..08ea69679086 100644
--- a/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/SimpleProperties.java.txt
+++ b/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/SimpleProperties.java.txt
@@ -12,7 +12,7 @@ import java.lang.Override;
  * Generated by {@link android.processor.view.inspector.InspectionCompanionGenerator}
  * on behalf of {@link android.processor.view.inspector.InspectionCompanionGeneratorTest}.
  */
-public final class TestNode$$InspectionCompanion implements InspectionCompanion<TestNode> {
+public final class TestNode$InspectionCompanion implements InspectionCompanion<TestNode> {
     /**
      * Set by {@link #mapProperties(PropertyMapper)} once properties have been mapped.
      */
diff --git a/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/SuppliedAttributeId.java.txt b/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/SuppliedAttributeId.java.txt
index d72cdd533205..3bfa78ac857f 100644
--- a/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/SuppliedAttributeId.java.txt
+++ b/tools/processors/view_inspector/test/resources/android/processor/view/inspector/InspectionCompanionGeneratorTest/SuppliedAttributeId.java.txt
@@ -11,7 +11,7 @@ import java.lang.Override;
  * Generated by {@link android.processor.view.inspector.InspectionCompanionGenerator}
  * on behalf of {@link android.processor.view.inspector.InspectionCompanionGeneratorTest}.
  */
-public final class TestNode$$InspectionCompanion implements InspectionCompanion<TestNode> {
+public final class TestNode$InspectionCompanion implements InspectionCompanion<TestNode> {
     /**
      * Set by {@link #mapProperties(PropertyMapper)} once properties have been mapped.
      */