SoundPool: Fix lifetime of SoundPool native object (48c07950) · Commits · e / os / android_frameworks_base

media/jni/soundpool/android_media_SoundPool.cpp

+206 −58

Original line number	Diff line number	Diff line
		@@ -33,10 +33,156 @@ static struct fields_t {
		jmethodID mPostEvent;
		jclass mSoundPoolClass;
		} fields;
		static inline SoundPool* MusterSoundPool(JNIEnv *env, jobject thiz) {

		namespace {

		/**
		* ObjectManager creates a native "object" on the heap and stores
		* its pointer in a long field in a Java object.
		*
		* The type T must have 3 properties in the current implementation.
		* 1) A T{} default constructor which represents a nullValue.
		* 2) T::operator bool() const efficient detection of such a nullValue.
		* 3) T must be copyable.
		*
		* Some examples of such a type T are std::shared_ptr<>, android::sp<>,
		* std::optional, std::function<>, etc.
		*
		* Using set() with a nullValue T results in destroying the underlying native
		* "object" if it exists. A nullValue T is returned by get() if there is
		* no underlying native Object.
		*
		* This class is thread safe for multiple access.
		*
		* Design notes:
		* 1) For objects of type T that do not naturally have an "nullValue",
		* wrapping with
		* a) TOpt, where TOpt = std::optional<T>
		* b) TShared, where TShared = std::shared_ptr<T>
		*
		* 2) An overload for an explicit equality comparable nullValue such as
		* get(..., const T& nullValue) or set(..., const T& nullValue)
		* is omitted. An alternative is to pass a fixed nullValue in the constructor.
		*/
		template <typename T>
		class ObjectManager
		{
		// Can a jlong hold a pointer?
		static_assert(sizeof(jlong) >= sizeof(void*));

		public:
		// fieldId is associated with a Java long member variable in the object.
		// ObjectManager will store the native pointer in that field.
		//
		// If a native object is set() in that field, it
		explicit ObjectManager(jfieldID fieldId) : mFieldId(fieldId) {}
		~ObjectManager() {
		ALOGE_IF(mObjectCount != 0, "%s: mObjectCount: %d should be zero on destruction",
		__func__, mObjectCount.load());
		// Design note: it would be possible to keep a map of the outstanding allocated
		// objects and force a delete on them on ObjectManager destruction.
		// The consequences of that is probably worse than keeping them alive.
		}

		// Retrieves the associated object, returns nullValue T if not available.
		T get(JNIEnv *env, jobject thiz) {
		std::lock_guard lg(mLock);
		// NOLINTNEXTLINE(performance-no-int-to-ptr)
		auto ptr = reinterpret_cast<T*>(env->GetLongField(thiz, mFieldId));
		if (ptr != nullptr) {
		return *ptr;
		}
		return {};
		}

		// Sets the object and returns the old one.
		//
		// If the old object doesn't exist, then nullValue T is returned.
		// If the new object is false by operator bool(), the internal object is destroyed.
		// Note: The old object is returned so if T is a smart pointer, it can be held
		// by the caller to be deleted outside of any external lock.
		//
		// Remember to call set(env, thiz, {}) to destroy the object in the Java
		// object finalize to avoid orphaned objects on the heap.
		T set(JNIEnv *env, jobject thiz, const T& newObject) {
		std::lock_guard lg(mLock);
		// NOLINTNEXTLINE(performance-no-int-to-ptr)
		return reinterpret_cast<SoundPool*>(env->GetLongField(thiz, fields.mNativeContext));
		auto ptr = reinterpret_cast<T*>(env->GetLongField(thiz, mFieldId));
		if (ptr != nullptr) {
		T old = std::move(ptr); // ptr will be replaced or deleted.
		if (newObject) {
		env->SetLongField(thiz, mFieldId, (jlong)0);
		delete ptr;
		--mObjectCount;
		} else {
		*ptr = newObject;
		}
		return old;
		} else {
		if (newObject) {
		env->SetLongField(thiz, mFieldId, (jlong)new T(newObject));
		++mObjectCount;
		}
		return {};
		}
		}

		// Returns the number of outstanding objects.
		//
		// This is purely for debugging purposes and tracks the number of active Java
		// objects that have native T objects; hence represents the number of
		// T heap allocations we have made.
		//
		// When all those Java objects have been finalized we expect this to go to 0.
		int32_t getObjectCount() const {
		return mObjectCount;
		}

		private:
		// NOLINTNEXTLINE(misc-misplaced-const)
		const jfieldID mFieldId; // '_jfieldID *const'

		// mObjectCount is the number of outstanding native T heap allocations we have
		// made (and thus the number of active Java objects which are associated with them).
		std::atomic_int32_t mObjectCount{};

		mutable std::mutex mLock;
		};

		// We use SoundPoolManager to associate a native std::shared_ptr<SoundPool>
		// object with a field in the Java object.
		//
		// We can then retrieve the std::shared_ptr<SoundPool> from the object.
		//
		// Design notes:
		// 1) This is based on ObjectManager class.
		// 2) An alternative that does not require a field in the Java object
		// is to create an associative map using as a key a NewWeakGlobalRef
		// to the Java object.
		// The problem of this method is that lookup is O(N) because comparison
		// between the WeakGlobalRef to a JNI jobject LocalRef must be done
		// through the JNI IsSameObject() call, hence iterative through the map.
		// One advantage of this method is that manual garbage collection
		// is possible by checking if the WeakGlobalRef is null equivalent.

		auto& getSoundPoolManager() {
		static ObjectManager<std::shared_ptr<SoundPool>> soundPoolManager(fields.mNativeContext);
		return soundPoolManager;
		}

		inline auto getSoundPool(JNIEnv *env, jobject thiz) {
		return getSoundPoolManager().get(env, thiz);
		}

		// Note: one must call setSoundPool(env, thiz, nullptr) to release any native resources
		// somewhere in the Java object finalize().
		inline auto setSoundPool(
		JNIEnv *env, jobject thiz, const std::shared_ptr<SoundPool>& soundPool) {
		return getSoundPoolManager().set(env, thiz, soundPool);
		}

		} // namespace

		static const char* const kAudioAttributesClassPathName = "android/media/AudioAttributes";
		struct audio_attributes_fields_t {
		jfieldID fieldUsage; // AudioAttributes.mUsage
		@@ -53,18 +199,18 @@ android_media_SoundPool_load_FD(JNIEnv *env, jobject thiz, jobject fileDescripto
		jlong offset, jlong length, jint priority)
		{
		ALOGV("android_media_SoundPool_load_FD");
		SoundPool *ap = MusterSoundPool(env, thiz);
		if (ap == nullptr) return 0;
		return (jint) ap->load(jniGetFDFromFileDescriptor(env, fileDescriptor),
		auto soundPool = getSoundPool(env, thiz);
		if (soundPool == nullptr) return 0;
		return (jint) soundPool->load(jniGetFDFromFileDescriptor(env, fileDescriptor),
		int64_t(offset), int64_t(length), int(priority));
		}

		static jboolean
		android_media_SoundPool_unload(JNIEnv *env, jobject thiz, jint sampleID) {
		ALOGV("android_media_SoundPool_unload\n");
		SoundPool *ap = MusterSoundPool(env, thiz);
		if (ap == nullptr) return JNI_FALSE;
		return ap->unload(sampleID) ? JNI_TRUE : JNI_FALSE;
		auto soundPool = getSoundPool(env, thiz);
		if (soundPool == nullptr) return JNI_FALSE;
		return soundPool->unload(sampleID) ? JNI_TRUE : JNI_FALSE;
		}

		static jint
		@@ -73,54 +219,54 @@ android_media_SoundPool_play(JNIEnv *env, jobject thiz, jint sampleID,
		jfloat rate)
		{
		ALOGV("android_media_SoundPool_play\n");
		SoundPool *ap = MusterSoundPool(env, thiz);
		if (ap == nullptr) return 0;
		return (jint) ap->play(sampleID, leftVolume, rightVolume, priority, loop, rate);
		auto soundPool = getSoundPool(env, thiz);
		if (soundPool == nullptr) return 0;
		return (jint) soundPool->play(sampleID, leftVolume, rightVolume, priority, loop, rate);
		}

		static void
		android_media_SoundPool_pause(JNIEnv *env, jobject thiz, jint channelID)
		{
		ALOGV("android_media_SoundPool_pause");
		SoundPool *ap = MusterSoundPool(env, thiz);
		if (ap == nullptr) return;
		ap->pause(channelID);
		auto soundPool = getSoundPool(env, thiz);
		if (soundPool == nullptr) return;
		soundPool->pause(channelID);
		}

		static void
		android_media_SoundPool_resume(JNIEnv *env, jobject thiz, jint channelID)
		{
		ALOGV("android_media_SoundPool_resume");
		SoundPool *ap = MusterSoundPool(env, thiz);
		if (ap == nullptr) return;
		ap->resume(channelID);
		auto soundPool = getSoundPool(env, thiz);
		if (soundPool == nullptr) return;
		soundPool->resume(channelID);
		}

		static void
		android_media_SoundPool_autoPause(JNIEnv *env, jobject thiz)
		{
		ALOGV("android_media_SoundPool_autoPause");
		SoundPool *ap = MusterSoundPool(env, thiz);
		if (ap == nullptr) return;
		ap->autoPause();
		auto soundPool = getSoundPool(env, thiz);
		if (soundPool == nullptr) return;
		soundPool->autoPause();
		}

		static void
		android_media_SoundPool_autoResume(JNIEnv *env, jobject thiz)
		{
		ALOGV("android_media_SoundPool_autoResume");
		SoundPool *ap = MusterSoundPool(env, thiz);
		if (ap == nullptr) return;
		ap->autoResume();
		auto soundPool = getSoundPool(env, thiz);
		if (soundPool == nullptr) return;
		soundPool->autoResume();
		}

		static void
		android_media_SoundPool_stop(JNIEnv *env, jobject thiz, jint channelID)
		{
		ALOGV("android_media_SoundPool_stop");
		SoundPool *ap = MusterSoundPool(env, thiz);
		if (ap == nullptr) return;
		ap->stop(channelID);
		auto soundPool = getSoundPool(env, thiz);
		if (soundPool == nullptr) return;
		soundPool->stop(channelID);
		}

		static void
		@@ -128,18 +274,18 @@ android_media_SoundPool_setVolume(JNIEnv *env, jobject thiz, jint channelID,
		jfloat leftVolume, jfloat rightVolume)
		{
		ALOGV("android_media_SoundPool_setVolume");
		SoundPool *ap = MusterSoundPool(env, thiz);
		if (ap == nullptr) return;
		ap->setVolume(channelID, (float) leftVolume, (float) rightVolume);
		auto soundPool = getSoundPool(env, thiz);
		if (soundPool == nullptr) return;
		soundPool->setVolume(channelID, (float) leftVolume, (float) rightVolume);
		}

		static void
		android_media_SoundPool_mute(JNIEnv *env, jobject thiz, jboolean muting)
		{
		ALOGV("android_media_SoundPool_mute(%d)", muting);
		SoundPool *ap = MusterSoundPool(env, thiz);
		if (ap == nullptr) return;
		ap->mute(muting == JNI_TRUE);
		auto soundPool = getSoundPool(env, thiz);
		if (soundPool == nullptr) return;
		soundPool->mute(muting == JNI_TRUE);
		}

		static void
		@@ -147,9 +293,9 @@ android_media_SoundPool_setPriority(JNIEnv *env, jobject thiz, jint channelID,
		jint priority)
		{
		ALOGV("android_media_SoundPool_setPriority");
		SoundPool *ap = MusterSoundPool(env, thiz);
		if (ap == nullptr) return;
		ap->setPriority(channelID, (int) priority);
		auto soundPool = getSoundPool(env, thiz);
		if (soundPool == nullptr) return;
		soundPool->setPriority(channelID, (int) priority);
		}

		static void
		@@ -157,9 +303,9 @@ android_media_SoundPool_setLoop(JNIEnv *env, jobject thiz, jint channelID,
		int loop)
		{
		ALOGV("android_media_SoundPool_setLoop");
		SoundPool *ap = MusterSoundPool(env, thiz);
		if (ap == nullptr) return;
		ap->setLoop(channelID, loop);
		auto soundPool = getSoundPool(env, thiz);
		if (soundPool == nullptr) return;
		soundPool->setLoop(channelID, loop);
		}

		static void
		@@ -167,9 +313,9 @@ android_media_SoundPool_setRate(JNIEnv *env, jobject thiz, jint channelID,
		jfloat rate)
		{
		ALOGV("android_media_SoundPool_setRate");
		SoundPool *ap = MusterSoundPool(env, thiz);
		if (ap == nullptr) return;
		ap->setRate(channelID, (float) rate);
		auto soundPool = getSoundPool(env, thiz);
		if (soundPool == nullptr) return;
		soundPool->setRate(channelID, (float) rate);
		}

		static void android_media_callback(SoundPoolEvent event, SoundPool* soundPool, void* user)
		@@ -206,17 +352,16 @@ android_media_SoundPool_native_setup(JNIEnv *env, jobject thiz, jobject weakRef,

		ALOGV("android_media_SoundPool_native_setup");
		ScopedUtfChars opPackageNameStr(env, opPackageName);
		auto *ap = new SoundPool(maxChannels, paa, opPackageNameStr.c_str());
		if (ap == nullptr) {
		return -1;
		}

		// save pointer to SoundPool C++ object in opaque field in Java object
		env->SetLongField(thiz, fields.mNativeContext, (jlong) ap);
		auto soundPool = std::make_shared<SoundPool>(maxChannels, paa, opPackageNameStr.c_str());

		// set callback with weak reference
		jobject globalWeakRef = env->NewGlobalRef(weakRef);
		ap->setCallback(android_media_callback, globalWeakRef);
		soundPool->setCallback(android_media_callback, globalWeakRef);

		// register with SoundPoolManager.
		auto oldSoundPool = setSoundPool(env, thiz, soundPool);
		ALOGW_IF(oldSoundPool != nullptr, "%s: Aliased SoundPool object %p",
		__func__, oldSoundPool.get());

		// audio attributes were copied in SoundPool creation
		free(paa);
		@@ -228,20 +373,23 @@ static void
		android_media_SoundPool_release(JNIEnv *env, jobject thiz)
		{
		ALOGV("android_media_SoundPool_release");
		SoundPool *ap = MusterSoundPool(env, thiz);
		if (ap != nullptr) {

		// Remove us from SoundPoolManager.
		auto oldSoundPool = setSoundPool(env, thiz, nullptr);

		// Caution: Deleting the weakRef is not race free from invoking
		// the Java callback because we may not have the last remaining
		// reference to the SoundPool object - another method could still
		// be in progress.
		if (oldSoundPool != nullptr) {
		// release weak reference and clear callback
		auto weakRef = (jobject) ap->getUserData();
		ap->setCallback(nullptr /* callback /, nullptr / user */);
		auto weakRef = (jobject) oldSoundPool->getUserData();
		oldSoundPool->setCallback(nullptr /* callback /, nullptr / user */);
		if (weakRef != nullptr) {
		env->DeleteGlobalRef(weakRef);
		}

		// clear native context
		env->SetLongField(thiz, fields.mNativeContext, 0);
		delete ap;
		}
		// destructor to oldSoundPool should occur at exit.
		}

		// ----------------------------------------------------------------------------