Support generation of Parcelable nano messages.

This CL adds the "parcelable_messages" option. When enabled, all
generated message classes will conform to the Android Parcelable
contract. This is achieved by introducing a new parent class for
generated classes which implements the required functionality.

Since the store_unknown_fields option also makes use of a superclass,
ExtendableMessageNano, we have two versions of the new Parcelable
superclass: one extending MessageNano, and one extending
ExtendableMessageNano. These classes are otherwise identical.

As these classes depend on Android framework jars, they are not
included in the host .jar build of the nanoproto library.

Finally, add a test suite for running tests of Android-specific
functionality, as this cannot be done on a desktop JVM.

Change-Id: Icc2a257f03317e947f7078dbb9857c3286857497

5 files changed, 91 insertions, 3 deletions

diff --git a/Android.mk b/Android.mk
index ec28bec8..faf6e393 100644
--- a/Android.mk
+++ b/Android.mk
@@ -142,6 +142,7 @@ LOCAL_MODULE_TAGS := optional
 LOCAL_SDK_VERSION := 8
 
 LOCAL_SRC_FILES := $(call all-java-files-under, java/src/main/java/com/google/protobuf/nano)
+LOCAL_SRC_FILES += $(call all-java-files-under, java/src/device/main/java/com/google/protobuf/nano)
 
 include $(BUILD_STATIC_JAVA_LIBRARY)
 
@@ -379,3 +380,63 @@ LOCAL_PROTO_JAVA_OUTPUT_PARAMS := \
         java_outer_classname = $(LOCAL_PATH)/src/google/protobuf/unittest_import_nano.proto|UnittestImportNano
 
 include $(BUILD_STATIC_JAVA_LIBRARY)
+
+# To test Android-specific nanoproto features.
+# =======================================================
+include $(CLEAR_VARS)
+
+# Parcelable messages
+LOCAL_MODULE := android-nano-test-parcelable
+LOCAL_MODULE_TAGS := tests
+LOCAL_SDK_VERSION := current
+
+LOCAL_PROTOC_OPTIMIZE_TYPE := nano
+
+LOCAL_SRC_FILES := src/google/protobuf/unittest_simple_nano.proto
+
+LOCAL_PROTOC_FLAGS := --proto_path=$(LOCAL_PATH)/src
+
+LOCAL_PROTO_JAVA_OUTPUT_PARAMS := \
+        parcelable_messages = true
+
+include $(BUILD_STATIC_JAVA_LIBRARY)
+
+include $(CLEAR_VARS)
+
+# Parcelable and extendable messages
+LOCAL_MODULE := android-nano-test-parcelable-extendable
+LOCAL_MODULE_TAGS := tests
+LOCAL_SDK_VERSION := current
+
+LOCAL_PROTOC_OPTIMIZE_TYPE := nano
+
+LOCAL_SRC_FILES := src/google/protobuf/unittest_extension_nano.proto
+
+LOCAL_PROTOC_FLAGS := --proto_path=$(LOCAL_PATH)/src
+
+LOCAL_PROTO_JAVA_OUTPUT_PARAMS := \
+        parcelable_messages = true, \
+        store_unknown_fields = true
+
+include $(BUILD_STATIC_JAVA_LIBRARY)
+
+include $(CLEAR_VARS)
+
+# Test APK
+LOCAL_PACKAGE_NAME := NanoAndroidTest
+
+LOCAL_SDK_VERSION := 8
+
+LOCAL_MODULE_TAGS := tests
+
+LOCAL_SRC_FILES := $(call all-java-files-under, java/src/device/test/java/com/google/protobuf/nano)
+
+LOCAL_MANIFEST_FILE := java/src/device/test/AndroidManifest.xml
+
+LOCAL_STATIC_JAVA_LIBRARIES := libprotobuf-java-2.3.0-nano \
+        android-nano-test-parcelable \
+        android-nano-test-parcelable-extendable
+
+WITH_DEXPREOPT := false
+
+include $(BUILD_PACKAGE)
diff --git a/java/README.txt b/java/README.txt
index f922c4be..c6933138 100644
--- a/java/README.txt
+++ b/java/README.txt
@@ -476,6 +476,7 @@ java_nano_generate_has -> true or false [DEPRECATED]
 optional_field_style   -> default or accessors
 enum_style             -> c or java
 ignore_services        -> true or false
+parcelable_messages    -> true or false
 
 java_package:
 java_outer_classname:
@@ -588,6 +589,9 @@ ignore_services={true,false} (default: false)
   it will generate a compilation error. If this flag is set to true,
   services will be silently ignored, instead.
 
+parcelable_messages={true,false} (default: false)
+  Android-specific option to generate Parcelable messages.
+
 
 To use nano protobufs within the Android repo:
 
@@ -638,8 +642,13 @@ Please run the following steps to test:
 - cd ../../..
 - . build/envsetup.sh
 - lunch 1
-- "make -j12 aprotoc libprotobuf-java-2.3.0-nano aprotoc-test-nano-params" and
+- "make -j12 aprotoc libprotobuf-java-2.3.0-nano aprotoc-test-nano-params NanoAndroidTest" and
   check for build errors.
+- Plug in an Android device or start an emulator.
+- adb install -r out/target/product/generic/data/app/NanoAndroidTest.apk
+- Run:
+  "adb shell am instrument -w com.google.protobuf.nano.test/android.test.InstrumentationTestRunner"
+  and verify all tests pass.
 - repo sync -c -j256
 - "make -j12" and check for build errors
 
diff --git a/src/google/protobuf/compiler/javanano/javanano_generator.cc b/src/google/protobuf/compiler/javanano/javanano_generator.cc
index 0e121033..61ef2caa 100644
--- a/src/google/protobuf/compiler/javanano/javanano_generator.cc
+++ b/src/google/protobuf/compiler/javanano/javanano_generator.cc
@@ -144,6 +144,8 @@ bool JavaNanoGenerator::Generate(const FileDescriptor* file,
       params.set_generate_equals(option_value == "true");
     } else if (option_name == "ignore_services") {
       params.set_ignore_services(option_value == "true");
+    } else if (option_name == "parcelable_messages") {
+      params.set_parcelable_messages(option_value == "true");
     } else {
       *error = "Ignore unknown javanano generator option: " + option_name;
     }
diff --git a/src/google/protobuf/compiler/javanano/javanano_message.cc b/src/google/protobuf/compiler/javanano/javanano_message.cc
index 3a1b5a50..0cf9f971 100644
--- a/src/google/protobuf/compiler/javanano/javanano_message.cc
+++ b/src/google/protobuf/compiler/javanano/javanano_message.cc
@@ -132,10 +132,17 @@ void MessageGenerator::Generate(io::Printer* printer) {
       "public static final class $classname$ extends\n",
       "classname", descriptor_->name());
   }
-  if (params_.store_unknown_fields()) {
+  if (params_.store_unknown_fields() && params_.parcelable_messages()) {
+    printer->Print(
+      "    com.google.protobuf.nano.android.ParcelableExtendableMessageNano<$classname$> {\n",
+      "classname", descriptor_->name());
+  } else if (params_.store_unknown_fields()) {
     printer->Print(
       "    com.google.protobuf.nano.ExtendableMessageNano<$classname$> {\n",
       "classname", descriptor_->name());
+  } else if (params_.parcelable_messages()) {
+    printer->Print(
+      "    com.google.protobuf.nano.android.ParcelableMessageNano {\n");
   } else {
     printer->Print(
       "    com.google.protobuf.nano.MessageNano {\n");
diff --git a/src/google/protobuf/compiler/javanano/javanano_params.h b/src/google/protobuf/compiler/javanano/javanano_params.h
index 889395e3..d0626a2c 100644
--- a/src/google/protobuf/compiler/javanano/javanano_params.h
+++ b/src/google/protobuf/compiler/javanano/javanano_params.h
@@ -63,6 +63,7 @@ class Params {
   bool use_reference_types_for_primitives_;
   bool generate_equals_;
   bool ignore_services_;
+  bool parcelable_messages_;
 
  public:
   Params(const string & base_name) :
@@ -75,7 +76,8 @@ class Params {
     optional_field_accessors_(false),
     use_reference_types_for_primitives_(false),
     generate_equals_(false),
-    ignore_services_(false) {
+    ignore_services_(false),
+    parcelable_messages_(false) {
   }
 
   const string& base_name() const {
@@ -204,6 +206,13 @@ class Params {
   bool ignore_services() const {
     return ignore_services_;
   }
+
+  void set_parcelable_messages(bool value) {
+    parcelable_messages_ = value;
+  }
+  bool parcelable_messages() const {
+    return parcelable_messages_;
+  }
 };
 
 }  // namespace javanano