[ggj][codegen] feat: add package-info.java codegen

src/main/java/com/google/api/generator/engine/ast/PackageInfoDefinition.java

@@ -30,6 +30,8 @@ public abstract class PackageInfoDefinition implements AstNode {
 
   public abstract ImmutableList<AnnotationNode> annotations();
 
+  public abstract Builder toBuilder();
+
   @Override
   public void accept(AstNodeVisitor visitor) {
     visitor.visit(this);

src/main/java/com/google/api/generator/gapic/Generator.java

@@ -17,6 +17,7 @@
 import com.google.api.generator.gapic.composer.Composer;
 import com.google.api.generator.gapic.model.GapicClass;
 import com.google.api.generator.gapic.model.GapicContext;
+import com.google.api.generator.gapic.model.GapicPackageInfo;
 import com.google.api.generator.gapic.protoparser.Parser;
 import com.google.api.generator.gapic.protowriter.Writer;
 import com.google.protobuf.compiler.PluginProtos.CodeGeneratorRequest;
@@ -27,8 +28,9 @@ public class Generator {
   public static CodeGeneratorResponse generateGapic(CodeGeneratorRequest request) {
     GapicContext context = Parser.parse(request);
     List<GapicClass> clazzes = Composer.composeServiceClasses(context);
+    GapicPackageInfo packageInfo = Composer.composePackageInfo(context);
     String outputFilename = "temp-codegen.srcjar";
-    CodeGeneratorResponse response = Writer.writeCode(clazzes, outputFilename);
+    CodeGeneratorResponse response = Writer.writeCode(clazzes, packageInfo, outputFilename);
     return response;
   }
 }

src/main/java/com/google/api/generator/gapic/composer/ClientLibraryPackageInfoComposer.java

@@ -0,0 +1,43 @@
+// Copyright 2020 Google LLC
+//
+// 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.google.api.generator.gapic.composer;
+
+import com.google.api.generator.engine.ast.AnnotationNode;
+import com.google.api.generator.engine.ast.ConcreteReference;
+import com.google.api.generator.engine.ast.PackageInfoDefinition;
+import com.google.api.generator.engine.ast.TypeNode;
+import com.google.api.generator.gapic.model.GapicContext;
+import com.google.api.generator.gapic.model.GapicPackageInfo;
+import com.google.common.base.Preconditions;
+import javax.annotation.Generated;
+
+public class ClientLibraryPackageInfoComposer {
+  public static GapicPackageInfo generatePackageInfo(GapicContext context) {
+    Preconditions.checkState(!context.services().isEmpty(), "No services found to generate");
+    // Pick some service's package, as we assume they are all the same.
+    String libraryPakkage = context.services().get(0).pakkage();
+
+    PackageInfoDefinition packageInfo =
+        PackageInfoDefinition.builder()
+            .setPakkage(libraryPakkage)
+            .setAnnotations(
+                AnnotationNode.builder()
+                    .setType(TypeNode.withReference(ConcreteReference.withClazz(Generated.class)))
+                    .setDescription("by gapic-generator-java")
+                    .build())
+            .build();
+    return GapicPackageInfo.with(packageInfo);
+  }
+}

src/main/java/com/google/api/generator/gapic/composer/Composer.java

@@ -19,6 +19,7 @@
 import com.google.api.generator.gapic.model.GapicClass;
 import com.google.api.generator.gapic.model.GapicClass.Kind;
 import com.google.api.generator.gapic.model.GapicContext;
+import com.google.api.generator.gapic.model.GapicPackageInfo;
 import com.google.api.generator.gapic.model.GapicServiceConfig;
 import com.google.api.generator.gapic.model.Message;
 import com.google.api.generator.gapic.model.ResourceName;
@@ -49,6 +50,10 @@ public static List<GapicClass> composeServiceClasses(GapicContext context) {
     return addApacheLicense(clazzes);
   }
 
+  public static GapicPackageInfo composePackageInfo(GapicContext context) {
+    return addApacheLicense(ClientLibraryPackageInfoComposer.generatePackageInfo(context));
+  }
+
   public static List<GapicClass> generateServiceClasses(
       @Nonnull Service service,
       @Nullable GapicServiceConfig serviceConfig,
@@ -131,4 +136,13 @@ protected static List<GapicClass> addApacheLicense(List<GapicClass> gapicClassLi
             })
         .collect(Collectors.toList());
   }
+
+  private static GapicPackageInfo addApacheLicense(GapicPackageInfo gapicPackageInfo) {
+    return GapicPackageInfo.with(
+        gapicPackageInfo
+            .packageInfo()
+            .toBuilder()
+            .setFileHeader(CommentComposer.APACHE_LICENSE_COMMENT)
+            .build());
+  }
 }

src/main/java/com/google/api/generator/gapic/model/GapicPackageInfo.java

@@ -0,0 +1,39 @@
+// Copyright 2020 Google LLC
+//
+// 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.google.api.generator.gapic.model;
+
+import com.google.api.generator.engine.ast.PackageInfoDefinition;
+import com.google.auto.value.AutoValue;
+
+/** A thin wrapper around PackageInfoDefinition to maintain a clean separation of concerns. */
+@AutoValue
+public abstract class GapicPackageInfo {
+  public abstract PackageInfoDefinition packageInfo();
+
+  public static GapicPackageInfo with(PackageInfoDefinition packageInfo) {
+    return builder().setPackageInfo(packageInfo).build();
+  }
+
+  static Builder builder() {
+    return new AutoValue_GapicPackageInfo.Builder();
+  }
+
+  @AutoValue.Builder
+  abstract static class Builder {
+    abstract Builder setPackageInfo(PackageInfoDefinition packageInfo);
+
+    abstract GapicPackageInfo build();
+  }
+}

src/main/java/com/google/api/generator/gapic/protowriter/Writer.java

@@ -15,8 +15,10 @@
 package com.google.api.generator.gapic.protowriter;
 
 import com.google.api.generator.engine.ast.ClassDefinition;
+import com.google.api.generator.engine.ast.PackageInfoDefinition;
 import com.google.api.generator.engine.writer.JavaWriterVisitor;
 import com.google.api.generator.gapic.model.GapicClass;
+import com.google.api.generator.gapic.model.GapicPackageInfo;
 import com.google.protobuf.ByteString;
 import com.google.protobuf.compiler.PluginProtos.CodeGeneratorResponse;
 import java.io.IOException;
@@ -31,7 +33,8 @@ public GapicWriterException(String errorMessage) {
     }
   }
 
-  public static CodeGeneratorResponse writeCode(List<GapicClass> clazzes, String outputFilePath) {
+  public static CodeGeneratorResponse writeCode(
+      List<GapicClass> clazzes, GapicPackageInfo gapicPackageInfo, String outputFilePath) {
     ByteString.Output output = ByteString.newOutput();
     JavaWriterVisitor codeWriter = new JavaWriterVisitor();
     JarOutputStream jos = null;
@@ -62,6 +65,21 @@ public static CodeGeneratorResponse writeCode(List<GapicClass> clazzes, String o
       }
     }
 
+    // Write the package info.
+    PackageInfoDefinition packageInfo = gapicPackageInfo.packageInfo();
+    packageInfo.accept(codeWriter);
+    String code = codeWriter.write();
+    codeWriter.clear();
+
+    String path = "src/main/java/" + packageInfo.pakkage().replaceAll("\\.", "/");
+    JarEntry jarEntry = new JarEntry(String.format("%s/package-info.java", path));
+    try {
+      jos.putNextEntry(jarEntry);
+      jos.write(code.getBytes());
+    } catch (IOException e) {
+      throw new GapicWriterException("Could not write code for package-info.java");
+    }
+
     try {
       jos.finish();
       jos.flush();