audio: Fix the lifetime of the StreamWorker's logic part am: 0b9c5feed1 am: 4b279d6a32 (231ca12c) · Commits · e / os / android_hardware_interfaces

audio/aidl/common/Android.bp

+5 −2

Original line number	Original line	Diff line number	Diff line
	@@ -23,7 +23,7 @@ package {
	default_applicable_licenses: ["hardware_interfaces_license"],		default_applicable_licenses: ["hardware_interfaces_license"],
	}		}

	cc_library_headers {		cc_library {
	name: "libaudioaidlcommon",		name: "libaudioaidlcommon",
	host_supported: true,		host_supported: true,
	vendor_available: true,		vendor_available: true,
	@@ -36,13 +36,16 @@ cc_library_headers {
	"libbase_headers",		"libbase_headers",
	"libsystem_headers",		"libsystem_headers",
	],		],
			srcs: [
			"StreamWorker.cpp",
			],
	}		}

	cc_test {		cc_test {
	name: "libaudioaidlcommon_test",		name: "libaudioaidlcommon_test",
	host_supported: true,		host_supported: true,
	vendor_available: true,		vendor_available: true,
	header_libs: [		static_libs: [
	"libaudioaidlcommon",		"libaudioaidlcommon",
	],		],
	shared_libs: [		shared_libs: [

audio/aidl/common/StreamWorker.cpp

0 → 100644

+160 −0

Original line number	Original line	Diff line number	Diff line
			/*
			* Copyright (C) 2022 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.
			*/

			#include <pthread.h>
			#include <sched.h>
			#include <sys/resource.h>

			#include "include/StreamWorker.h"

			namespace android::hardware::audio::common::internal {

			bool ThreadController::start(const std::string& name, int priority) {
			mThreadName = name;
			mThreadPriority = priority;
			mWorker = std::thread(&ThreadController::workerThread, this);
			std::unique_lock<std::mutex> lock(mWorkerLock);
			android::base::ScopedLockAssertion lock_assertion(mWorkerLock);
			mWorkerCv.wait(lock, [&]() {
			android::base::ScopedLockAssertion lock_assertion(mWorkerLock);
			return mWorkerState == WorkerState::RUNNING \|\| !mError.empty();
			});
			mWorkerStateChangeRequest = false;
			return mWorkerState == WorkerState::RUNNING;
			}

			void ThreadController::stop() {
			{
			std::lock_guard<std::mutex> lock(mWorkerLock);
			if (mWorkerState != WorkerState::STOPPED) {
			mWorkerState = WorkerState::STOPPED;
			mWorkerStateChangeRequest = true;
			}
			}
			if (mWorker.joinable()) {
			mWorker.join();
			}
			}

			bool ThreadController::waitForAtLeastOneCycle() {
			WorkerState newState;
			switchWorkerStateSync(WorkerState::RUNNING, WorkerState::PAUSE_REQUESTED, &newState);
			if (newState != WorkerState::PAUSED) return false;
			switchWorkerStateSync(newState, WorkerState::RESUME_REQUESTED, &newState);
			return newState == WorkerState::RUNNING;
			}

			void ThreadController::switchWorkerStateSync(WorkerState oldState, WorkerState newState,
			WorkerState* finalState) {
			std::unique_lock<std::mutex> lock(mWorkerLock);
			android::base::ScopedLockAssertion lock_assertion(mWorkerLock);
			if (mWorkerState != oldState) {
			if (finalState) *finalState = mWorkerState;
			return;
			}
			mWorkerState = newState;
			mWorkerStateChangeRequest = true;
			mWorkerCv.wait(lock, [&]() {
			android::base::ScopedLockAssertion lock_assertion(mWorkerLock);
			return mWorkerState != newState;
			});
			if (finalState) *finalState = mWorkerState;
			}

			void ThreadController::workerThread() {
			using Status = StreamLogic::Status;

			std::string error = mLogic->init();
			if (error.empty() && !mThreadName.empty()) {
			std::string compliantName(mThreadName.substr(0, 15));
			if (int errCode = pthread_setname_np(pthread_self(), compliantName.c_str()); errCode != 0) {
			error.append("Failed to set thread name: ").append(strerror(errCode));
			}
			}
			if (error.empty() && mThreadPriority != ANDROID_PRIORITY_DEFAULT) {
			if (int result = setpriority(PRIO_PROCESS, 0, mThreadPriority); result != 0) {
			int errCode = errno;
			error.append("Failed to set thread priority: ").append(strerror(errCode));
			}
			}
			{
			std::lock_guard<std::mutex> lock(mWorkerLock);
			mWorkerState = error.empty() ? WorkerState::RUNNING : WorkerState::STOPPED;
			mError = error;
			}
			mWorkerCv.notify_one();
			if (!error.empty()) return;

			for (WorkerState state = WorkerState::RUNNING; state != WorkerState::STOPPED;) {
			bool needToNotify = false;
			if (Status status = state != WorkerState::PAUSED ? mLogic->cycle()
			: (sched_yield(), Status::CONTINUE);
			status == Status::CONTINUE) {
			{
			// See https://developer.android.com/training/articles/smp#nonracing
			android::base::ScopedLockAssertion lock_assertion(mWorkerLock);
			if (!mWorkerStateChangeRequest.load(std::memory_order_relaxed)) continue;
			}
			//
			// Pause and resume are synchronous. One worker cycle must complete
			// before the worker indicates a state change. This is how 'mWorkerState' and
			// 'state' interact:
			//
			// mWorkerState == RUNNING
			// client sets mWorkerState := PAUSE_REQUESTED
			// last workerCycle gets executed, state := mWorkerState := PAUSED by us
			// (or the workers enters the 'error' state if workerCycle fails)
			// client gets notified about state change in any case
			// thread is doing a busy wait while 'state == PAUSED'
			// client sets mWorkerState := RESUME_REQUESTED
			// state := mWorkerState (RESUME_REQUESTED)
			// mWorkerState := RUNNING, but we don't notify the client yet
			// first workerCycle gets executed, the code below triggers a client notification
			// (or if workerCycle fails, worker enters 'error' state and also notifies)
			// state := mWorkerState (RUNNING)
			std::lock_guard<std::mutex> lock(mWorkerLock);
			if (state == WorkerState::RESUME_REQUESTED) {
			needToNotify = true;
			}
			state = mWorkerState;
			if (mWorkerState == WorkerState::PAUSE_REQUESTED) {
			state = mWorkerState = WorkerState::PAUSED;
			needToNotify = true;
			} else if (mWorkerState == WorkerState::RESUME_REQUESTED) {
			mWorkerState = WorkerState::RUNNING;
			}
			} else {
			std::lock_guard<std::mutex> lock(mWorkerLock);
			if (state == WorkerState::RESUME_REQUESTED \|\|
			mWorkerState == WorkerState::PAUSE_REQUESTED) {
			needToNotify = true;
			}
			state = mWorkerState = WorkerState::STOPPED;
			if (status == Status::ABORT) {
			mError = "Received ABORT from the logic cycle";
			}
			}
			if (needToNotify) {
			{
			std::lock_guard<std::mutex> lock(mWorkerLock);
			mWorkerStateChangeRequest = false;
			}
			mWorkerCv.notify_one();
			}
			}
			}

			} // namespace android::hardware::audio::common::internal

audio/aidl/common/include/StreamWorker.h

+83 −163

Original line number	Original line	Diff line number	Diff line
	@@ -16,10 +16,6 @@

	#pragma once		#pragma once

	#include <pthread.h>
	#include <sched.h>
	#include <sys/resource.h>

	#include <atomic>		#include <atomic>
	#include <condition_variable>		#include <condition_variable>
	#include <mutex>		#include <mutex>
	@@ -31,32 +27,18 @@

	namespace android::hardware::audio::common {		namespace android::hardware::audio::common {

	template <typename Impl>		class StreamLogic;
	class StreamWorker {
			namespace internal {

			class ThreadController {
	enum class WorkerState { STOPPED, RUNNING, PAUSE_REQUESTED, PAUSED, RESUME_REQUESTED };		enum class WorkerState { STOPPED, RUNNING, PAUSE_REQUESTED, PAUSED, RESUME_REQUESTED };

	public:		public:
	enum class WorkerStatus { ABORT, CONTINUE, EXIT };		explicit ThreadController(StreamLogic* logic) : mLogic(logic) {}
			~ThreadController() { stop(); }

	StreamWorker() = default;		bool start(const std::string& name, int priority);
	~StreamWorker() { stop(); }
	// Note that 'priority' here is what is known as the 'nice number' in *nix systems.
	// The nice number is used with the default scheduler. For threads that
	// need to use a specialized scheduler (e.g. SCHED_FIFO) and set the priority within it,
	// it is recommended to implement an appropriate configuration sequence within `workerInit`.
	bool start(const std::string& name = "", int priority = ANDROID_PRIORITY_DEFAULT) {
	mThreadName = name;
	mThreadPriority = priority;
	mWorker = std::thread(&StreamWorker::workerThread, this);
	std::unique_lock<std::mutex> lock(mWorkerLock);
	android::base::ScopedLockAssertion lock_assertion(mWorkerLock);
	mWorkerCv.wait(lock, [&]() {
	android::base::ScopedLockAssertion lock_assertion(mWorkerLock);
	return mWorkerState == WorkerState::RUNNING \|\| !mError.empty();
	});
	mWorkerStateChangeRequest = false;
	return mWorkerState == WorkerState::RUNNING;
	}
	void pause() { switchWorkerStateSync(WorkerState::RUNNING, WorkerState::PAUSE_REQUESTED); }		void pause() { switchWorkerStateSync(WorkerState::RUNNING, WorkerState::PAUSE_REQUESTED); }
	void resume() { switchWorkerStateSync(WorkerState::PAUSED, WorkerState::RESUME_REQUESTED); }		void resume() { switchWorkerStateSync(WorkerState::PAUSED, WorkerState::RESUME_REQUESTED); }
	bool hasError() {		bool hasError() {
	@@ -67,150 +49,21 @@ class StreamWorker {
	std::lock_guard<std::mutex> lock(mWorkerLock);		std::lock_guard<std::mutex> lock(mWorkerLock);
	return mError;		return mError;
	}		}
	void stop() {		void stop();
	{		bool waitForAtLeastOneCycle();
	std::lock_guard<std::mutex> lock(mWorkerLock);
	if (mWorkerState != WorkerState::STOPPED) {
	mWorkerState = WorkerState::STOPPED;
	mWorkerStateChangeRequest = true;
	}
	}
	if (mWorker.joinable()) {
	mWorker.join();
	}
	}
	bool waitForAtLeastOneCycle() {
	WorkerState newState;
	switchWorkerStateSync(WorkerState::RUNNING, WorkerState::PAUSE_REQUESTED, &newState);
	if (newState != WorkerState::PAUSED) return false;
	switchWorkerStateSync(newState, WorkerState::RESUME_REQUESTED, &newState);
	return newState == WorkerState::RUNNING;
	}
	// Only used by unit tests.		// Only used by unit tests.
	void testLockUnlockMutex(bool lock) NO_THREAD_SAFETY_ANALYSIS {		void lockUnlockMutex(bool lock) NO_THREAD_SAFETY_ANALYSIS {
	lock ? mWorkerLock.lock() : mWorkerLock.unlock();		lock ? mWorkerLock.lock() : mWorkerLock.unlock();
	}		}
	std::thread::native_handle_type testGetThreadNativeHandle() { return mWorker.native_handle(); }		std::thread::native_handle_type getThreadNativeHandle() { return mWorker.native_handle(); }

	// Methods that need to be provided by subclasses:
	//
	// /* Called once at the beginning of the thread loop. Must return
	// * an empty string to enter the thread loop, otherwise the thread loop
	// * exits and the worker switches into the 'error' state, setting
	// * the error to the returned value.
	// */
	// std::string workerInit();
	//
	// /* Called for each thread loop unless the thread is in 'paused' state.
	// * Must return 'CONTINUE' to continue running, otherwise the thread loop
	// * exits. If the result from worker cycle is 'ABORT' then the worker switches
	// * into the 'error' state with a generic error message. It is recommended that
	// * the subclass reports any problems via logging facilities. Returning the 'EXIT'
	// * status is equivalent to calling 'stop()' method. This is just a way of
	// * of stopping the worker by its own initiative.
	// */
	// WorkerStatus workerCycle();

	private:		private:
	void switchWorkerStateSync(WorkerState oldState, WorkerState newState,		void switchWorkerStateSync(WorkerState oldState, WorkerState newState,
	WorkerState* finalState = nullptr) {		WorkerState* finalState = nullptr);
	std::unique_lock<std::mutex> lock(mWorkerLock);		void workerThread();
	android::base::ScopedLockAssertion lock_assertion(mWorkerLock);
	if (mWorkerState != oldState) {
	if (finalState) *finalState = mWorkerState;
	return;
	}
	mWorkerState = newState;
	mWorkerStateChangeRequest = true;
	mWorkerCv.wait(lock, [&]() {
	android::base::ScopedLockAssertion lock_assertion(mWorkerLock);
	return mWorkerState != newState;
	});
	if (finalState) *finalState = mWorkerState;
	}
	void workerThread() {
	std::string error = static_cast<Impl*>(this)->workerInit();
	if (error.empty() && !mThreadName.empty()) {
	std::string compliantName(mThreadName.substr(0, 15));
	if (int errCode = pthread_setname_np(pthread_self(), compliantName.c_str());
	errCode != 0) {
	error.append("Failed to set thread name: ").append(strerror(errCode));
	}
	}
	if (error.empty() && mThreadPriority != ANDROID_PRIORITY_DEFAULT) {
	if (int result = setpriority(PRIO_PROCESS, 0, mThreadPriority); result != 0) {
	int errCode = errno;
	error.append("Failed to set thread priority: ").append(strerror(errCode));
	}
	}
	{
	std::lock_guard<std::mutex> lock(mWorkerLock);
	mWorkerState = error.empty() ? WorkerState::RUNNING : WorkerState::STOPPED;
	mError = error;
	}
	mWorkerCv.notify_one();
	if (!error.empty()) return;

	for (WorkerState state = WorkerState::RUNNING; state != WorkerState::STOPPED;) {
	bool needToNotify = false;
	if (WorkerStatus status = state != WorkerState::PAUSED
	? static_cast<Impl*>(this)->workerCycle()
	: (sched_yield(), WorkerStatus::CONTINUE);
	status == WorkerStatus::CONTINUE) {
	{
	// See https://developer.android.com/training/articles/smp#nonracing
	android::base::ScopedLockAssertion lock_assertion(mWorkerLock);
	if (!mWorkerStateChangeRequest.load(std::memory_order_relaxed)) continue;
	}
	//
	// Pause and resume are synchronous. One worker cycle must complete
	// before the worker indicates a state change. This is how 'mWorkerState' and
	// 'state' interact:
	//
	// mWorkerState == RUNNING
	// client sets mWorkerState := PAUSE_REQUESTED
	// last workerCycle gets executed, state := mWorkerState := PAUSED by us
	// (or the workers enters the 'error' state if workerCycle fails)
	// client gets notified about state change in any case
	// thread is doing a busy wait while 'state == PAUSED'
	// client sets mWorkerState := RESUME_REQUESTED
	// state := mWorkerState (RESUME_REQUESTED)
	// mWorkerState := RUNNING, but we don't notify the client yet
	// first workerCycle gets executed, the code below triggers a client notification
	// (or if workerCycle fails, worker enters 'error' state and also notifies)
	// state := mWorkerState (RUNNING)
	std::lock_guard<std::mutex> lock(mWorkerLock);
	if (state == WorkerState::RESUME_REQUESTED) {
	needToNotify = true;
	}
	state = mWorkerState;
	if (mWorkerState == WorkerState::PAUSE_REQUESTED) {
	state = mWorkerState = WorkerState::PAUSED;
	needToNotify = true;
	} else if (mWorkerState == WorkerState::RESUME_REQUESTED) {
	mWorkerState = WorkerState::RUNNING;
	}
	} else {
	std::lock_guard<std::mutex> lock(mWorkerLock);
	if (state == WorkerState::RESUME_REQUESTED \|\|
	mWorkerState == WorkerState::PAUSE_REQUESTED) {
	needToNotify = true;
	}
	state = mWorkerState = WorkerState::STOPPED;
	if (status == WorkerStatus::ABORT) {
	mError = "workerCycle aborted";
	}
	}
	if (needToNotify) {
	{
	std::lock_guard<std::mutex> lock(mWorkerLock);
	mWorkerStateChangeRequest = false;
	}
	mWorkerCv.notify_one();
	}
	}
	}

			StreamLogic* const mLogic;
	std::string mThreadName;		std::string mThreadName;
	int mThreadPriority = ANDROID_PRIORITY_DEFAULT;		int mThreadPriority = ANDROID_PRIORITY_DEFAULT;
	std::thread mWorker;		std::thread mWorker;
	@@ -230,4 +83,71 @@ class StreamWorker {
	std::atomic<bool> mWorkerStateChangeRequest GUARDED_BY(mWorkerLock) = false;		std::atomic<bool> mWorkerStateChangeRequest GUARDED_BY(mWorkerLock) = false;
	};		};

			} // namespace internal

			class StreamLogic {
			public:
			friend class internal::ThreadController;

			virtual ~StreamLogic() = default;

			protected:
			enum class Status { ABORT, CONTINUE, EXIT };

			/* Called once at the beginning of the thread loop. Must return
			* an empty string to enter the thread loop, otherwise the thread loop
			* exits and the worker switches into the 'error' state, setting
			* the error to the returned value.
			*/
			virtual std::string init() = 0;

			/* Called for each thread loop unless the thread is in 'paused' state.
			* Must return 'CONTINUE' to continue running, otherwise the thread loop
			* exits. If the result from worker cycle is 'ABORT' then the worker switches
			* into the 'error' state with a generic error message. It is recommended that
			* the subclass reports any problems via logging facilities. Returning the 'EXIT'
			* status is equivalent to calling 'stop()' method. This is just a way of
			* of stopping the worker by its own initiative.
			*/
			virtual Status cycle() = 0;
			};

			template <class LogicImpl>
			class StreamWorker : public LogicImpl {
			public:
			template <class... Args>
			explicit StreamWorker(Args&&... args) : LogicImpl(std::forward<Args>(args)...), mThread(this) {}

			// Methods of LogicImpl are available via inheritance.
			// Forwarded methods of ThreadController follow.

			// Note that 'priority' here is what is known as the 'nice number' in *nix systems.
			// The nice number is used with the default scheduler. For threads that
			// need to use a specialized scheduler (e.g. SCHED_FIFO) and set the priority within it,
			// it is recommended to implement an appropriate configuration sequence within
			// 'LogicImpl' or 'StreamLogic::init'.
			bool start(const std::string& name = "", int priority = ANDROID_PRIORITY_DEFAULT) {
			return mThread.start(name, priority);
			}
			void pause() { mThread.pause(); }
			void resume() { mThread.resume(); }
			bool hasError() { return mThread.hasError(); }
			std::string getError() { return mThread.getError(); }
			void stop() { return mThread.stop(); }
			bool waitForAtLeastOneCycle() { return mThread.waitForAtLeastOneCycle(); }

			// Only used by unit tests.
			void testLockUnlockMutex(bool lock) { mThread.lockUnlockMutex(lock); }
			std::thread::native_handle_type testGetThreadNativeHandle() {
			return mThread.getThreadNativeHandle();
			}

			private:
			// The ThreadController gets destroyed before LogicImpl.
			// After the controller has been destroyed, it is guaranteed that
			// the thread was joined, thus the 'cycle' method of LogicImpl
			// will not be called anymore, and it is safe to destroy LogicImpl.
			internal::ThreadController mThread;
			};

	} // namespace android::hardware::audio::common		} // namespace android::hardware::audio::common

audio/aidl/common/tests/streamworker_tests.cpp

+12 −7

Original line number	Original line	Diff line number	Diff line
	@@ -16,6 +16,7 @@

	#include <pthread.h>		#include <pthread.h>
	#include <sched.h>		#include <sched.h>
			#include <sys/resource.h>
	#include <unistd.h>		#include <unistd.h>

	#include <atomic>		#include <atomic>
	@@ -26,18 +27,19 @@
	#define LOG_TAG "StreamWorker_Test"		#define LOG_TAG "StreamWorker_Test"
	#include <log/log.h>		#include <log/log.h>

			using android::hardware::audio::common::StreamLogic;
	using android::hardware::audio::common::StreamWorker;		using android::hardware::audio::common::StreamWorker;

	class TestWorker : public StreamWorker<TestWorker> {		class TestWorkerLogic : public StreamLogic {
	public:		public:
	struct Stream {		struct Stream {
	void setErrorStatus() { status = WorkerStatus::ABORT; }		void setErrorStatus() { status = Status::ABORT; }
	void setStopStatus() { status = WorkerStatus::EXIT; }		void setStopStatus() { status = Status::EXIT; }
	std::atomic<WorkerStatus> status = WorkerStatus::CONTINUE;		std::atomic<Status> status = Status::CONTINUE;
	};		};

	// Use nullptr to test error reporting from the worker thread.		// Use nullptr to test error reporting from the worker thread.
	explicit TestWorker(Stream* stream) : mStream(stream) {}		explicit TestWorkerLogic(Stream* stream) : mStream(stream) {}

	size_t getWorkerCycles() const { return mWorkerCycles; }		size_t getWorkerCycles() const { return mWorkerCycles; }
	int getPriority() const { return mPriority; }		int getPriority() const { return mPriority; }
	@@ -48,8 +50,10 @@ class TestWorker : public StreamWorker<TestWorker> {
	return mWorkerCycles == cyclesBefore;		return mWorkerCycles == cyclesBefore;
	}		}

	std::string workerInit() { return mStream != nullptr ? "" : "Expected error"; }		protected:
	WorkerStatus workerCycle() {		// StreamLogic implementation
			std::string init() override { return mStream != nullptr ? "" : "Expected error"; }
			Status cycle() override {
	mPriority = getpriority(PRIO_PROCESS, 0);		mPriority = getpriority(PRIO_PROCESS, 0);
	do {		do {
	mWorkerCycles++;		mWorkerCycles++;
	@@ -62,6 +66,7 @@ class TestWorker : public StreamWorker<TestWorker> {
	std::atomic<size_t> mWorkerCycles = 0;		std::atomic<size_t> mWorkerCycles = 0;
	std::atomic<int> mPriority = ANDROID_PRIORITY_DEFAULT;		std::atomic<int> mPriority = ANDROID_PRIORITY_DEFAULT;
	};		};
			using TestWorker = StreamWorker<TestWorkerLogic>;

	// The parameter specifies whether an extra call to 'stop' is made at the end.		// The parameter specifies whether an extra call to 'stop' is made at the end.
	class StreamWorkerInvalidTest : public testing::TestWithParam<bool> {		class StreamWorkerInvalidTest : public testing::TestWithParam<bool> {

audio/aidl/default/Android.bp

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -11,6 +11,7 @@ cc_library_static {
	name: "libaudioserviceexampleimpl",		name: "libaudioserviceexampleimpl",
	vendor: true,		vendor: true,
	shared_libs: [		shared_libs: [
			"libaudioaidlcommon",
	"libbase",		"libbase",
	"libbinder_ndk",		"libbinder_ndk",
	"libstagefright_foundation",		"libstagefright_foundation",