utils/tests/service_singleton_tests.cpp

/*
 * Copyright (C) 2024 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.
 */

#define LOG_TAG "service_singleton_tests"

#include <mediautils/ServiceSingleton.h>

#include "BnServiceSingletonTest.h"
#include "aidl/BnServiceSingletonTest.h"
#include <audio_utils/RunRemote.h>
#include <binder/IPCThreadState.h>
#include <binder/ProcessState.h>
#include <gtest/gtest.h>
#include <utils/Log.h>

using namespace android;

/**
 * Service Singleton Test uses a worker process to spawn new binder services.
 *
 * A worker process is required since we cannot fork after registering
 * with the binder driver.
 *
 * Test Process -> Worker_Process -> Service Process(1)
 *                                -> Service Process(2)
 *                                -> ....
 */

// Service implementation.
class ServiceSingletonTestCpp : public BnServiceSingletonTest {
public:
    binder::Status inc(int32_t* _aidl_return) final {
        *_aidl_return = ++mValue;
        return binder::Status::ok();
    }
    std::atomic_int32_t mValue = 0;
};

// The service traits increment static atomic counters, which
// validates that the trait callbacks are invoked.
static std::atomic_int32_t sNewService = 0;
static std::atomic_int32_t sServiceDied = 0;

template <typename Service>
struct TestServiceTraits : public mediautils::DefaultServiceTraits<Service> {
    static constexpr const char* getServiceName() { return ""; }
    static constexpr void onNewService(const mediautils::InterfaceType<Service>&) {
        ++sNewService;
    }
    static constexpr void onServiceDied(const mediautils::InterfaceType<Service>&) {
        ++sServiceDied;
    }
};

// Here we have an alternative set of service traits,
// used to validate that we can switch traits for the service singleton.
static std::atomic_int32_t sNewService2 = 0;
static std::atomic_int32_t sServiceDied2 = 0;

template <typename Service>
struct TestServiceTraits2 : public mediautils::DefaultServiceTraits<Service> {
    static constexpr const char* getServiceName() { return ""; }
    static constexpr void onNewService(const mediautils::InterfaceType<Service>&) {
        ++sNewService2;
    }
    static constexpr void onServiceDied(const mediautils::InterfaceType<Service>&) {
        ++sServiceDied2;
    }
};

/*
 * ServiceThreads run in a remote process.
 *
 * The WorkerThread is used to launch and kill the ServiceThread in a remote process.
 */
static void ServiceThread(audio_utils::RunRemote& runRemote) {
    int c = runRemote.getc();  // requires any character to launch
    auto service = sp<IServiceSingletonTest>::cast(sp<ServiceSingletonTestCpp>::make());
    mediautils::addService(service);
    ProcessState::self()->startThreadPool();
    runRemote.putc(c);  // echo character.
    IPCThreadState::self()->joinThreadPool();
}

/*
 * The WorkerThread is run in a remote process from the test.  It communicates with
 * the test process through pipes.
 */
static void WorkerThread(audio_utils::RunRemote& runRemote) {
    std::shared_ptr<audio_utils::RunRemote> remoteService;
    while (true) {
        const int c = runRemote.getc();
        switch (c) {
            case 'a':  // launch a new service.
                // if the old service isn't destroyed, it will be destroyed here
                // when the RunRemote is replaced.
                remoteService = std::make_shared<audio_utils::RunRemote>(ServiceThread);
                remoteService->run();
                remoteService->putc('a');  // create service.
                (void)remoteService->getc(); // ensure it is created.
                runRemote.putc(c);  // echo
                break;
            case 'b':  // destroys the old service.
                remoteService.reset();  // this kills the service.
                runRemote.putc(c);  // echo
                break;
            default:  // respond that we don't know what happened!
                runRemote.putc('?');
                break;
        }
    }
}

// This is a monolithic test.
TEST(service_singleton_tests, one_and_only) {
    std::atomic_int32_t listenerServiceCreated = 0;
    std::atomic_int32_t listenerServiceDied = 0;

    // initialize the service cache with a custom handler.
    mediautils::initService<
        IServiceSingletonTest, TestServiceTraits<IServiceSingletonTest>>({});
    mediautils::initService<
        aidl::IServiceSingletonTest, TestServiceTraits<aidl::IServiceSingletonTest>>({});

    // start the worker thread that spawns the services.
    auto remoteWorker = std::make_shared<audio_utils::RunRemote>(WorkerThread);
    remoteWorker->run();

    // now we are ready for binder.
    ProcessState::self()->startThreadPool();

    // check that our service isn't preexisting.
    {
        auto service = mediautils::checkServicePassThrough<IServiceSingletonTest>();
        EXPECT_FALSE(service);

        auto service2 = mediautils::checkServicePassThrough<aidl::IServiceSingletonTest>();
        EXPECT_FALSE(service2);
    }
    EXPECT_EQ(0, sNewService);
    EXPECT_EQ(0, sServiceDied);

    {
        auto service = mediautils::checkService<IServiceSingletonTest>();
        EXPECT_FALSE(service);

        auto service2 = mediautils::checkService<aidl::IServiceSingletonTest>();
        EXPECT_FALSE(service2);
    }
    EXPECT_EQ(0, sNewService);
    EXPECT_EQ(0, sServiceDied);

    // getService will register a notification handler that fetches the
    // service in the background.
    {
        auto service = mediautils::getService<IServiceSingletonTest>();
        EXPECT_FALSE(service);

        auto service2 = mediautils::getService<aidl::IServiceSingletonTest>();
        EXPECT_FALSE(service2);
    }
    EXPECT_EQ(0, sNewService);
    EXPECT_EQ(0, sServiceDied);

    // now spawn the service.
    remoteWorker->putc('a');
    EXPECT_EQ('a', remoteWorker->getc());

    sleep(1);  // In the background, 2 services were fetched.

    EXPECT_EQ(2, sNewService);
    EXPECT_EQ(0, sServiceDied);

    // we repeat the prior checks, but the service is cached now.
    {
        auto service = mediautils::checkServicePassThrough<IServiceSingletonTest>();
        EXPECT_TRUE(service);

        auto service2 = mediautils::checkServicePassThrough<aidl::IServiceSingletonTest>();
        EXPECT_TRUE(service2);
    }
    EXPECT_EQ(2, sNewService);
    EXPECT_EQ(0, sServiceDied);

    {
        auto service = mediautils::checkService<IServiceSingletonTest>();
        EXPECT_TRUE(service);

        auto service2 = mediautils::checkService<aidl::IServiceSingletonTest>();
        EXPECT_TRUE(service2);
    }
    EXPECT_EQ(2, sNewService);
    EXPECT_EQ(0, sServiceDied);

    {
        auto service = mediautils::getService<IServiceSingletonTest>();
        EXPECT_TRUE(service);

        auto service2 = mediautils::getService<aidl::IServiceSingletonTest>();
        EXPECT_TRUE(service2);
    }
    EXPECT_EQ(2, sNewService);
    EXPECT_EQ(0, sServiceDied);

    // destroy the service.
    remoteWorker->putc('b');
    EXPECT_EQ('b', remoteWorker->getc());

    sleep(1);

    // We expect the died callbacks.
    EXPECT_EQ(2, sNewService);
    EXPECT_EQ(2, sServiceDied);

    // we can also manually check whether there is a new service by
    // requesting service notifications.  This is outside of the service singleton
    // traits.
    auto handle1 = mediautils::requestServiceNotification<IServiceSingletonTest>(
            [&](const sp<IServiceSingletonTest>&) { ++listenerServiceCreated; });
    auto handle2 = mediautils::requestServiceNotification<aidl::IServiceSingletonTest>(
            [&](const std::shared_ptr<aidl::IServiceSingletonTest>&) {
                ++listenerServiceCreated; });

    // Spawn the service again.
    remoteWorker->putc('a');
    EXPECT_EQ('a', remoteWorker->getc());

    sleep(1);  // In the background, 2 services were fetched.

    EXPECT_EQ(4, sNewService);
    EXPECT_EQ(2, sServiceDied);

    EXPECT_EQ(2, listenerServiceCreated);  // our listener picked up the service creation.

    std::shared_ptr<void> handle3, handle4;
    std::shared_ptr<aidl::IServiceSingletonTest> keepAlive;  // NDK Workaround!
    {
        auto service = mediautils::getService<IServiceSingletonTest>();
        EXPECT_TRUE(service);

        // mediautils::getService<> is a cached service.
        // pointer equality is preserved for subsequent requests.
        auto service_equal = mediautils::getService<IServiceSingletonTest>();
        EXPECT_EQ(service, service_equal);
        EXPECT_TRUE(mediautils::isSameInterface(service, service_equal));

        // we can create an alias to the service by requesting it outside of the cache.
        // this is a different pointer, but same underlying binder object.
        auto service_equivalent =
                mediautils::checkServicePassThrough<IServiceSingletonTest>();
        EXPECT_NE(service, service_equivalent);
        EXPECT_TRUE(mediautils::isSameInterface(service, service_equivalent));

        auto service2 = mediautils::getService<aidl::IServiceSingletonTest>();
        EXPECT_TRUE(service2);

        // mediautils::getService<> is a cached service.
        // pointer equality is preserved for subsequent requests.
        auto service2_equal = mediautils::getService<aidl::IServiceSingletonTest>();
        EXPECT_EQ(service2, service2_equal);
        EXPECT_TRUE(mediautils::isSameInterface(service2, service2_equal));

        // we can create an alias to the service by requesting it outside of the cache.
        // this is a different pointer, but same underlying binder object.
        auto service2_equivalent =
                mediautils::checkServicePassThrough<aidl::IServiceSingletonTest>();
        EXPECT_NE(service2, service2_equivalent);
        EXPECT_TRUE(mediautils::isSameInterface(service2, service2_equivalent));

        keepAlive = service2;

        // we can also request our own death notifications (outside of the service traits).
        handle3 = mediautils::requestDeathNotification(service, [&] { ++listenerServiceDied; });
        EXPECT_TRUE(handle3);
        handle4 = mediautils::requestDeathNotification(service2, [&] { ++listenerServiceDied; });
        EXPECT_TRUE(handle4);
    }

    EXPECT_EQ(4, sNewService);
    EXPECT_EQ(2, sServiceDied);

    // destroy the service.

    remoteWorker->putc('b');
    EXPECT_EQ('b', remoteWorker->getc());

    sleep(1);

    // We expect the died callbacks.
    EXPECT_EQ(4, sNewService);
    EXPECT_EQ(4, sServiceDied);

    EXPECT_EQ(2, listenerServiceCreated);
    EXPECT_EQ(2, listenerServiceDied);  // NDK Workaround - without keepAlive, this is 1.
                                        // the death notification is invalidated without a
                                        // pointer to the binder object.

    keepAlive.reset();

    // Cancel the singleton cache.
    mediautils::skipService<IServiceSingletonTest>();
    mediautils::skipService<aidl::IServiceSingletonTest>();

    // Spawn the service again.
    remoteWorker->putc('a');
    EXPECT_EQ('a', remoteWorker->getc());

    sleep(1);

    // We expect no change from the service traits (service not cached).
    EXPECT_EQ(4, sNewService);
    EXPECT_EQ(4, sServiceDied);
    EXPECT_EQ(4, listenerServiceCreated);  // our listener picks it up.

    {
        // in default mode (kNull) a null is returned when the service is skipped and
        // wait time is ignored.

        const auto ref1 = std::chrono::steady_clock::now();
        auto service = mediautils::getService<IServiceSingletonTest>(std::chrono::seconds(2));
        EXPECT_FALSE(service);
        const auto ref2 = std::chrono::steady_clock::now();
        EXPECT_LT(ref2 - ref1, std::chrono::seconds(1));

        auto service2 = mediautils::getService<aidl::IServiceSingletonTest>(
                std::chrono::seconds(2));
        EXPECT_FALSE(service2);
        const auto ref3 = std::chrono::steady_clock::now();
        EXPECT_LT(ref3 - ref2, std::chrono::seconds(1));
    }

    // Cancel the singleton cache but use wait mode.
    mediautils::skipService<IServiceSingletonTest>(mediautils::SkipMode::kWait);
    mediautils::skipService<aidl::IServiceSingletonTest>(mediautils::SkipMode::kWait);

    {
        // in wait mode, the timeouts are respected
        const auto ref1 = std::chrono::steady_clock::now();
        auto service = mediautils::getService<IServiceSingletonTest>(std::chrono::seconds(1));
        EXPECT_FALSE(service);
        const auto ref2 = std::chrono::steady_clock::now();
        EXPECT_GT(ref2 - ref1, std::chrono::seconds(1));

        auto service2 = mediautils::getService<aidl::IServiceSingletonTest>(
                std::chrono::seconds(1));
        EXPECT_FALSE(service2);
        const auto ref3 = std::chrono::steady_clock::now();
        EXPECT_GT(ref3 - ref2, std::chrono::seconds(1));
    }

    // remove service
    remoteWorker->putc('b');
    EXPECT_EQ('b', remoteWorker->getc());

    sleep(1);

    // We expect no change from the service traits (service not cached).
    EXPECT_EQ(4, sNewService);
    EXPECT_EQ(4, sServiceDied);
    EXPECT_EQ(4, listenerServiceCreated);
    EXPECT_EQ(2, listenerServiceDied);  // binder died is associated with the actual handle.

    // replace the service traits.
    {
        auto previous = mediautils::initService<
                IServiceSingletonTest, TestServiceTraits2<IServiceSingletonTest>>({});
        auto previous2 = mediautils::initService<
                aidl::IServiceSingletonTest, TestServiceTraits2<aidl::IServiceSingletonTest>>({});

        EXPECT_FALSE(previous);
        EXPECT_FALSE(previous2);
    }

    // We expect no change with old counters.
    EXPECT_EQ(4, sNewService);
    EXPECT_EQ(4, sServiceDied);
    EXPECT_EQ(0, sNewService2);
    EXPECT_EQ(0, sServiceDied2);

    {
        auto service = mediautils::getService<IServiceSingletonTest>();
        EXPECT_FALSE(service);

        auto service2 = mediautils::getService<aidl::IServiceSingletonTest>();
        EXPECT_FALSE(service2);
    }

    EXPECT_EQ(4, sNewService);
    EXPECT_EQ(4, sServiceDied);
    EXPECT_EQ(0, sNewService2);
    EXPECT_EQ(0, sServiceDied2);

    // Spawn the service again.
    remoteWorker->putc('a');
    EXPECT_EQ('a', remoteWorker->getc());

    sleep(1);

    EXPECT_EQ(4, sNewService);   // old counters do not change.
    EXPECT_EQ(4, sServiceDied);
    EXPECT_EQ(2, sNewService2);  // new counters change
    EXPECT_EQ(0, sServiceDied2);

    EXPECT_EQ(6, listenerServiceCreated);  // listener associated with service name picks up info.

    // get service pointers that will be made stale later.
    auto stale_service = mediautils::getService<IServiceSingletonTest>();
    EXPECT_TRUE(stale_service);  // not stale yet.

    auto stale_service2 = mediautils::getService<aidl::IServiceSingletonTest>();
    EXPECT_TRUE(stale_service2);  // not stale yet.

    // Release the service.
    remoteWorker->putc('b');
    EXPECT_EQ('b', remoteWorker->getc());

    sleep(1);

    EXPECT_EQ(4, sNewService);    // old counters do not change.
    EXPECT_EQ(4, sServiceDied);
    EXPECT_EQ(2, sNewService2);   // new counters change
    EXPECT_EQ(2, sServiceDied2);

    // The service handles are now stale, verify that we can't register a death notification.
    {
        std::atomic_int32_t postDied = 0;
        // we cannot register death notification so handles are null.
        auto handle1 = mediautils::requestDeathNotification(stale_service, [&] { ++postDied; });
        EXPECT_FALSE(handle1);
        auto handle2= mediautils::requestDeathNotification(stale_service2, [&] { ++postDied; });
        EXPECT_FALSE(handle2);
        EXPECT_EQ(0, postDied);  // no callbacks issued.
    }
}