AppSearchCompiler.java
/*
* Copyright 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 androidx.appsearch.compiler;
import static javax.lang.model.util.ElementFilter.typesIn;
import androidx.annotation.NonNull;
import androidx.annotation.VisibleForTesting;
import com.google.auto.common.BasicAnnotationProcessor;
import com.google.auto.common.MoreElements;
import com.google.auto.value.AutoValue;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.ImmutableSetMultimap;
import java.io.File;
import java.io.IOException;
import java.util.Set;
import javax.annotation.processing.Messager;
import javax.annotation.processing.ProcessingEnvironment;
import javax.annotation.processing.SupportedAnnotationTypes;
import javax.annotation.processing.SupportedOptions;
import javax.annotation.processing.SupportedSourceVersion;
import javax.lang.model.SourceVersion;
import javax.lang.model.element.Element;
import javax.lang.model.element.ElementKind;
import javax.lang.model.element.TypeElement;
import javax.tools.Diagnostic.Kind;
/**
* Processes {@code androidx.appsearch.annotation.Document} annotations.
*
* <p>Only plain Java objects and AutoValue Document classes without builders are supported.
*/
@SupportedAnnotationTypes({IntrospectionHelper.DOCUMENT_ANNOTATION_CLASS})
@SupportedSourceVersion(SourceVersion.RELEASE_8)
@SupportedOptions({AppSearchCompiler.OUTPUT_DIR_OPTION})
public class AppSearchCompiler extends BasicAnnotationProcessor {
/**
* This property causes us to write output to a different folder instead of the usual filer
* location. It should only be used for testing.
*/
@VisibleForTesting
static final String OUTPUT_DIR_OPTION = "AppSearchCompiler.OutputDir";
@Override
@NonNull
public SourceVersion getSupportedSourceVersion() {
return SourceVersion.latestSupported();
}
@Override
protected Iterable<? extends Step> steps() {
return ImmutableList.of(new AppSearchCompileStep(processingEnv));
}
private static final class AppSearchCompileStep implements Step {
private final ProcessingEnvironment mProcessingEnv;
private final Messager mMessager;
AppSearchCompileStep(ProcessingEnvironment processingEnv) {
mProcessingEnv = processingEnv;
mMessager = processingEnv.getMessager();
}
@Override
public ImmutableSet<String> annotations() {
return ImmutableSet.of(IntrospectionHelper.DOCUMENT_ANNOTATION_CLASS);
}
@Override
public ImmutableSet<Element> process(
ImmutableSetMultimap<String, Element> elementsByAnnotation) {
Set<TypeElement> documentElements =
typesIn(elementsByAnnotation.get(
IntrospectionHelper.DOCUMENT_ANNOTATION_CLASS));
for (TypeElement document : documentElements) {
try {
processDocument(document);
} catch (MissingTypeException e) {
// Save it for next round to wait for the AutoValue annotation processor to
// be run first.
return ImmutableSet.of(e.getTypeName());
} catch (ProcessingException e) {
// Prints error message.
e.printDiagnostic(mMessager);
}
}
// No elements will be passed to next round of processing.
return ImmutableSet.of();
}
private void processDocument(@NonNull TypeElement element)
throws ProcessingException, MissingTypeException {
if (element.getKind() != ElementKind.CLASS) {
throw new ProcessingException(
"@Document annotation on something other than a class", element);
}
DocumentModel model;
if (element.getAnnotation(AutoValue.class) != null) {
// Document class is annotated as AutoValue class. For processing the AutoValue
// class, we also need the generated class from AutoValue annotation processor.
TypeElement generatedElement =
mProcessingEnv.getElementUtils().getTypeElement(
getAutoValueGeneratedClassName(element));
if (generatedElement == null) {
// Generated class is not found.
throw new MissingTypeException(element);
} else {
model = DocumentModel.createAutoValueModel(mProcessingEnv, element,
generatedElement);
}
} else {
// Non-AutoValue AppSearch Document class.
model = DocumentModel.createPojoModel(mProcessingEnv, element);
}
CodeGenerator generator = CodeGenerator.generate(mProcessingEnv, model);
String outputDir = mProcessingEnv.getOptions().get(OUTPUT_DIR_OPTION);
try {
if (outputDir == null || outputDir.isEmpty()) {
generator.writeToFiler();
} else {
mMessager.printMessage(
Kind.NOTE,
"Writing output to \"" + outputDir
+ "\" due to the presence of -A" + OUTPUT_DIR_OPTION);
generator.writeToFolder(new File(outputDir));
}
} catch (IOException e) {
ProcessingException pe =
new ProcessingException("Failed to write output", model.getClassElement());
pe.initCause(e);
throw pe;
}
}
/**
* Gets the generated class name of an AutoValue annotated class.
*
* <p>This is the same naming strategy used by AutoValue's processor.
*/
private String getAutoValueGeneratedClassName(TypeElement element) {
TypeElement type = element;
String name = type.getSimpleName().toString();
while (type.getEnclosingElement() instanceof TypeElement) {
type = (TypeElement) type.getEnclosingElement();
name = type.getSimpleName().toString() + "_" + name;
}
String pkg = MoreElements.getPackage(type).getQualifiedName().toString();
String dot = pkg.isEmpty() ? "" : ".";
return pkg + dot + "AutoValue_" + name;
}
}
}