Merge "TimeCheck: Dump TimerThread tasks on timeout" into tm-dev (2fe02dd1) · Commits · e / os / android_frameworks_av

media/utils/TimeCheck.cpp

+87 −18

Original line number	Diff line number	Diff line
		@@ -17,8 +17,8 @@
		#define LOG_TAG "TimeCheck"

		#include <optional>
		#include <sstream>

		#include <audio_utils/clock.h>
		#include <mediautils/EventLog.h>
		#include <mediautils/TimeCheck.h>
		#include <utils/Log.h>
		@@ -26,14 +26,68 @@

		namespace android::mediautils {

		namespace {

		/**
		* Returns the std::string "HH:MM:SS.MSc" from a system_clock time_point.
		*/
		std::string formatTime(std::chrono::system_clock::time_point t) {
		auto msSinceEpoch = std::chrono::round<std::chrono::milliseconds>(t.time_since_epoch());
		return (std::ostringstream() << msSinceEpoch.count()).str();
		auto time_string = audio_utils_time_string_from_ns(
		std::chrono::nanoseconds(t.time_since_epoch()).count());

		// The time string is 19 characters (including null termination).
		// Example: "03-27 16:47:06.187"
		// MM DD HH MM SS MS
		// We offset by 6 to get HH:MM:SS.MSc
		//
		return time_string.time + 6; // offset to remove month/day.
		}

		} // namespace
		/**
		* Finds the end of the common time prefix.
		*
		* This is as an option to remove the common time prefix to avoid
		* unnecessary duplicated strings.
		*
		* \param time1 a time string
		* \param time2 a time string
		* \return the position where the common time prefix ends. For abbreviated
		* printing of time2, offset the character pointer by this position.
		*/
		static size_t commonTimePrefixPosition(std::string_view time1, std::string_view time2) {
		const size_t endPos = std::min(time1.size(), time2.size());
		size_t i;

		// Find location of the first mismatch between strings
		for (i = 0; ; ++i) {
		if (i == endPos) {
		return i; // strings match completely to the length of one of the strings.
		}
		if (time1[i] != time2[i]) {
		break;
		}
		if (time1[i] == '\0') {
		return i; // "printed" strings match completely. No need to check further.
		}
		}

		// Go backwards until we find a delimeter or space.
		for (; i > 0
		&& isdigit(time1[i]) // still a number
		&& time1[i - 1] != ' '
		; --i) {
		}
		return i;
		}

		/**
		* Returns the unique suffix of time2 that isn't present in time1.
		*
		* If time2 is identical to time1, then an empty string_view is returned.
		* This method is used to elide the common prefix when printing times.
		*/
		std::string_view timeSuffix(std::string_view time1, std::string_view time2) {
		const size_t pos = commonTimePrefixPosition(time1, time2);
		return time2.substr(pos);
		}

		// Audio HAL server pids vector used to generate audio HAL processes tombstone
		// when audioserver watchdog triggers.
		@@ -75,24 +129,35 @@ TimerThread& TimeCheck::getTimeCheckThread() {
		return sTimeCheckThread;
		}

		/* static */
		std::string TimeCheck::toString() {
		// note pending and retired are individually locked for maximum concurrency,
		// snapshot is not instantaneous at a single time.
		return getTimeCheckThread().toString();
		}

		TimeCheck::TimeCheck(std::string tag, OnTimerFunc&& onTimer, uint32_t timeoutMs,
		bool crashOnTimeout)
		: mTimeCheckHandler(new TimeCheckHandler{
		std::move(tag), std::move(onTimer), crashOnTimeout,
		std::chrono::system_clock::now(), gettid()})
		, mTimerHandle(getTimeCheckThread().scheduleTask(
		, mTimerHandle(timeoutMs == 0
		? getTimeCheckThread().trackTask(mTimeCheckHandler->tag)
		: getTimeCheckThread().scheduleTask(
		mTimeCheckHandler->tag,
		// Pass in all the arguments by value to this task for safety.
		// The thread could call the callback before the constructor is finished.
		// The destructor will be blocked on the callback, but that is implementation
		// dependent.
		// The destructor is not blocked on callback.
		[ timeCheckHandler = mTimeCheckHandler ] {
		timeCheckHandler->onTimeout();
		},
		std::chrono::milliseconds(timeoutMs))) {}

		TimeCheck::~TimeCheck() {
		if (mTimeCheckHandler) {
		mTimeCheckHandler->onCancel(mTimerHandle);
		}
		}

		void TimeCheck::TimeCheckHandler::onCancel(TimerThread::Handle timerHandle) const
		{
		@@ -115,6 +180,10 @@ void TimeCheck::TimeCheckHandler::onTimeout() const

		if (!crashOnTimeout) return;

		// Generate the TimerThread summary string early before sending signals to the
		// HAL processes which can affect thread behavior.
		const std::string summary = getTimeCheckThread().toString(4 /* retiredCount */);

		// Generate audio HAL processes tombstones and allow time to complete
		// before forcing restart
		std::vector<pid_t> pids = TimeCheck::getAudioHalPids();
		@@ -128,8 +197,8 @@ void TimeCheck::TimeCheckHandler::onTimeout() const
		ALOGI("No HAL process pid available, skipping tombstones");
		}
		LOG_EVENT_STRING(LOGTAG_AUDIO_BINDER_TIMEOUT, tag.c_str());
		LOG_ALWAYS_FATAL("TimeCheck timeout for %s on thread %d (start=%s, end=%s)",
		tag.c_str(), tid, formatTime(startTime).c_str(), formatTime(endTime).c_str());
		LOG_ALWAYS_FATAL("TimeCheck timeout for %s scheduled %s on thread %d\n%s",
		tag.c_str(), formatTime(startTime).c_str(), tid, summary.c_str());
		}

		} // namespace android::mediautils

media/utils/TimerThread-test.cpp

+93 −14

Original line number	Diff line number	Diff line
		@@ -20,54 +20,71 @@
		#include <mediautils/TimerThread.h>

		using namespace std::chrono_literals;
		using namespace android::mediautils;

		namespace android {
		namespace {

		constexpr auto kJitter = 10ms;

		// Each task written by *ToString() will start with a left brace.
		constexpr char REQUEST_START = '{';

		inline size_t countChars(std::string_view s, char c) {
		return std::count(s.begin(), s.end(), c);
		}

		TEST(TimerThread, Basic) {
		std::atomic<bool> taskRan = false;
		TimerThread thread;
		thread.scheduleTask([&taskRan] { taskRan = true; }, 100ms);
		thread.scheduleTask("Basic", [&taskRan] { taskRan = true; }, 100ms);
		std::this_thread::sleep_for(100ms - kJitter);
		ASSERT_FALSE(taskRan);
		std::this_thread::sleep_for(2 * kJitter);
		ASSERT_TRUE(taskRan);
		ASSERT_EQ(1, countChars(thread.retiredToString(), REQUEST_START));
		}

		TEST(TimerThread, Cancel) {
		std::atomic<bool> taskRan = false;
		TimerThread thread;
		TimerThread::Handle handle = thread.scheduleTask([&taskRan] { taskRan = true; }, 100ms);
		TimerThread::Handle handle =
		thread.scheduleTask("Cancel", [&taskRan] { taskRan = true; }, 100ms);
		std::this_thread::sleep_for(100ms - kJitter);
		ASSERT_FALSE(taskRan);
		thread.cancelTask(handle);
		ASSERT_TRUE(thread.cancelTask(handle));
		std::this_thread::sleep_for(2 * kJitter);
		ASSERT_FALSE(taskRan);
		ASSERT_EQ(1, countChars(thread.retiredToString(), REQUEST_START));
		}

		TEST(TimerThread, CancelAfterRun) {
		std::atomic<bool> taskRan = false;
		TimerThread thread;
		TimerThread::Handle handle = thread.scheduleTask([&taskRan] { taskRan = true; }, 100ms);
		TimerThread::Handle handle =
		thread.scheduleTask("CancelAfterRun", [&taskRan] { taskRan = true; }, 100ms);
		std::this_thread::sleep_for(100ms + kJitter);
		ASSERT_TRUE(taskRan);
		thread.cancelTask(handle);
		ASSERT_FALSE(thread.cancelTask(handle));
		ASSERT_EQ(1, countChars(thread.retiredToString(), REQUEST_START));
		}

		TEST(TimerThread, MultipleTasks) {
		std::array<std::atomic<bool>, 6> taskRan;
		std::array<std::atomic<bool>, 6> taskRan{};
		TimerThread thread;

		auto startTime = std::chrono::steady_clock::now();

		thread.scheduleTask([&taskRan] { taskRan[0] = true; }, 300ms);
		thread.scheduleTask([&taskRan] { taskRan[1] = true; }, 100ms);
		thread.scheduleTask([&taskRan] { taskRan[2] = true; }, 200ms);
		thread.scheduleTask([&taskRan] { taskRan[3] = true; }, 400ms);
		auto handle4 = thread.scheduleTask([&taskRan] { taskRan[4] = true; }, 200ms);
		thread.scheduleTask([&taskRan] { taskRan[5] = true; }, 200ms);
		thread.scheduleTask("0", [&taskRan] { taskRan[0] = true; }, 300ms);
		thread.scheduleTask("1", [&taskRan] { taskRan[1] = true; }, 100ms);
		thread.scheduleTask("2", [&taskRan] { taskRan[2] = true; }, 200ms);
		thread.scheduleTask("3", [&taskRan] { taskRan[3] = true; }, 400ms);
		auto handle4 = thread.scheduleTask("4", [&taskRan] { taskRan[4] = true; }, 200ms);
		thread.scheduleTask("5", [&taskRan] { taskRan[5] = true; }, 200ms);

		// 6 tasks pending
		ASSERT_EQ(6, countChars(thread.pendingToString(), REQUEST_START));
		// 0 tasks completed
		ASSERT_EQ(0, countChars(thread.retiredToString(), REQUEST_START));

		// Task 1 should trigger around 100ms.
		std::this_thread::sleep_until(startTime + 100ms - kJitter);
		@@ -123,6 +140,11 @@ TEST(TimerThread, MultipleTasks) {
		ASSERT_FALSE(taskRan[4]);
		ASSERT_TRUE(taskRan[5]);

		// 1 task pending
		ASSERT_EQ(1, countChars(thread.pendingToString(), REQUEST_START));
		// 4 tasks ran and 1 cancelled
		ASSERT_EQ(4 + 1, countChars(thread.retiredToString(), REQUEST_START));

		// Task 3 should trigger around 400ms.
		std::this_thread::sleep_until(startTime + 400ms - kJitter);
		ASSERT_TRUE(taskRan[0]);
		@@ -132,6 +154,9 @@ TEST(TimerThread, MultipleTasks) {
		ASSERT_FALSE(taskRan[4]);
		ASSERT_TRUE(taskRan[5]);

		// 4 tasks ran and 1 cancelled
		ASSERT_EQ(4 + 1, countChars(thread.retiredToString(), REQUEST_START));

		std::this_thread::sleep_until(startTime + 400ms + kJitter);
		ASSERT_TRUE(taskRan[0]);
		ASSERT_TRUE(taskRan[1]);
		@@ -139,8 +164,62 @@ TEST(TimerThread, MultipleTasks) {
		ASSERT_TRUE(taskRan[3]);
		ASSERT_FALSE(taskRan[4]);
		ASSERT_TRUE(taskRan[5]);

		// 0 tasks pending
		ASSERT_EQ(0, countChars(thread.pendingToString(), REQUEST_START));
		// 5 tasks ran and 1 cancelled
		ASSERT_EQ(5 + 1, countChars(thread.retiredToString(), REQUEST_START));
		}

		TEST(TimerThread, TrackedTasks) {
		TimerThread thread;

		auto handle0 = thread.trackTask("0");
		auto handle1 = thread.trackTask("1");
		auto handle2 = thread.trackTask("2");

		// 3 tasks pending
		ASSERT_EQ(3, countChars(thread.pendingToString(), REQUEST_START));
		// 0 tasks retired
		ASSERT_EQ(0, countChars(thread.retiredToString(), REQUEST_START));

		ASSERT_TRUE(thread.cancelTask(handle0));
		ASSERT_TRUE(thread.cancelTask(handle1));

		// 1 task pending
		ASSERT_EQ(1, countChars(thread.pendingToString(), REQUEST_START));
		// 2 tasks retired
		ASSERT_EQ(2, countChars(thread.retiredToString(), REQUEST_START));

		// handle1 is stale, cancel returns false.
		ASSERT_FALSE(thread.cancelTask(handle1));

		// 1 task pending
		ASSERT_EQ(1, countChars(thread.pendingToString(), REQUEST_START));
		// 2 tasks retired
		ASSERT_EQ(2, countChars(thread.retiredToString(), REQUEST_START));

		// Add another tracked task.
		auto handle3 = thread.trackTask("3");

		// 2 tasks pending
		ASSERT_EQ(2, countChars(thread.pendingToString(), REQUEST_START));
		// 2 tasks retired
		ASSERT_EQ(2, countChars(thread.retiredToString(), REQUEST_START));

		ASSERT_TRUE(thread.cancelTask(handle2));

		// 1 tasks pending
		ASSERT_EQ(1, countChars(thread.pendingToString(), REQUEST_START));
		// 3 tasks retired
		ASSERT_EQ(3, countChars(thread.retiredToString(), REQUEST_START));

		ASSERT_TRUE(thread.cancelTask(handle3));

		// 0 tasks pending
		ASSERT_EQ(0, countChars(thread.pendingToString(), REQUEST_START));
		// 4 tasks retired
		ASSERT_EQ(4, countChars(thread.retiredToString(), REQUEST_START));
		}

		} // namespace
		} // namespace android

media/utils/TimerThread.cpp

+198 −29

Original line number	Diff line number	Diff line
		@@ -17,57 +17,195 @@
		#define LOG_TAG "TimerThread"

		#include <optional>
		#include <sstream>
		#include <unistd.h>
		#include <vector>

		#include <mediautils/TimerThread.h>
		#include <utils/ThreadDefs.h>

		namespace android {
		namespace android::mediautils {

		TimerThread::TimerThread() : mThread([this] { threadFunc(); }) {
		pthread_setname_np(mThread.native_handle(), "TimeCheckThread");
		pthread_setschedprio(mThread.native_handle(), PRIORITY_URGENT_AUDIO);
		extern std::string formatTime(std::chrono::system_clock::time_point t);
		extern std::string_view timeSuffix(std::string_view time1, std::string_view time2);

		TimerThread::Handle TimerThread::scheduleTask(
		std::string tag, std::function<void()>&& func, std::chrono::milliseconds timeout) {
		const auto now = std::chrono::system_clock::now();
		std::shared_ptr<const Request> request{
		new Request{ now, now + timeout, gettid(), std::move(tag) }};
		return mMonitorThread.add(std::move(request), std::move(func), timeout);
		}

		TimerThread::~TimerThread() {
		{
		std::lock_guard _l(mMutex);
		mShouldExit = true;
		mCond.notify_all();
		TimerThread::Handle TimerThread::trackTask(std::string tag) {
		const auto now = std::chrono::system_clock::now();
		std::shared_ptr<const Request> request{
		new Request{ now, now, gettid(), std::move(tag) }};
		return mNoTimeoutMap.add(std::move(request));
		}
		mThread.join();

		bool TimerThread::cancelTask(Handle handle) {
		std::shared_ptr<const Request> request = mNoTimeoutMap.isValidHandle(handle) ?
		mNoTimeoutMap.remove(handle) : mMonitorThread.remove(handle);
		if (!request) return false;
		mRetiredQueue.add(std::move(request));
		return true;
		}

		TimerThread::Handle TimerThread::scheduleTaskAtDeadline(std::function<void()>&& func,
		TimePoint deadline) {
		std::lock_guard _l(mMutex);
		std::string TimerThread::toString(size_t retiredCount) const {
		return std::string("now ")
		.append(formatTime(std::chrono::system_clock::now()))
		.append("\npending [ ")
		.append(pendingToString())
		.append(" ]\ntimeout [ ")
		.append(timeoutToString())
		.append(" ]\nretired [ ")
		.append(retiredToString(retiredCount))
		.append(" ]");
		}

		std::vector<std::shared_ptr<const TimerThread::Request>> TimerThread::getPendingRequests() const {
		constexpr size_t kEstimatedPendingRequests = 8; // approx 128 byte alloc.
		std::vector<std::shared_ptr<const Request>> pendingRequests;
		pendingRequests.reserve(kEstimatedPendingRequests); // preallocate vector out of lock.

		// following are internally locked calls, which add to our local pendingRequests.
		mMonitorThread.copyRequests(pendingRequests);
		mNoTimeoutMap.copyRequests(pendingRequests);

		// Sort in order of scheduled time.
		std::sort(pendingRequests.begin(), pendingRequests.end(),
		[](const std::shared_ptr<const Request>& r1,
		const std::shared_ptr<const Request>& r2) {
		return r1->scheduled < r2->scheduled;
		});
		return pendingRequests;
		}

		std::string TimerThread::pendingToString() const {
		return requestsToString(getPendingRequests());
		}

		std::string TimerThread::retiredToString(size_t n) const {
		std::vector<std::shared_ptr<const Request>> retiredRequests;
		mRetiredQueue.copyRequests(retiredRequests, n);

		// Dump to string
		return requestsToString(retiredRequests);
		}

		std::string TimerThread::timeoutToString(size_t n) const {
		std::vector<std::shared_ptr<const Request>> timeoutRequests;
		mTimeoutQueue.copyRequests(timeoutRequests, n);

		// Dump to string
		return requestsToString(timeoutRequests);
		}

		std::string TimerThread::Request::toString() const {
		const auto scheduledString = formatTime(scheduled);
		const auto deadlineString = formatTime(deadline);
		return std::string(tag)
		.append(" scheduled ").append(scheduledString)
		.append(" deadline ").append(timeSuffix(scheduledString, deadlineString))
		.append(" tid ").append(std::to_string(tid));
		}

		void TimerThread::RequestQueue::add(std::shared_ptr<const Request> request) {
		std::lock_guard lg(mRQMutex);
		mRequestQueue.emplace_back(std::chrono::system_clock::now(), std::move(request));
		if (mRequestQueue.size() > mRequestQueueMax) {
		mRequestQueue.pop_front();
		}
		}

		void TimerThread::RequestQueue::copyRequests(
		std::vector<std::shared_ptr<const Request>>& requests, size_t n) const {
		std::lock_guard lg(mRQMutex);
		const size_t size = mRequestQueue.size();
		size_t i = n >= size ? 0 : size - n;
		for (; i < size; ++i) {
		const auto &[time, request] = mRequestQueue[i];
		requests.emplace_back(request);
		}
		}

		bool TimerThread::NoTimeoutMap::isValidHandle(Handle handle) const {
		return handle > getIndexedHandle(mNoTimeoutRequests);
		}

		TimerThread::Handle TimerThread::NoTimeoutMap::add(std::shared_ptr<const Request> request) {
		std::lock_guard lg(mNTMutex);
		// A unique handle is obtained by mNoTimeoutRequests.fetch_add(1),
		// This need not be under a lock, but we do so anyhow.
		const Handle handle = getIndexedHandle(mNoTimeoutRequests++);
		mMap[handle] = request;
		return handle;
		}

		std::shared_ptr<const TimerThread::Request> TimerThread::NoTimeoutMap::remove(Handle handle) {
		std::lock_guard lg(mNTMutex);
		auto it = mMap.find(handle);
		if (it == mMap.end()) return {};
		auto request = it->second;
		mMap.erase(it);
		return request;
		}

		void TimerThread::NoTimeoutMap::copyRequests(
		std::vector<std::shared_ptr<const Request>>& requests) const {
		std::lock_guard lg(mNTMutex);
		for (const auto &[handle, request] : mMap) {
		requests.emplace_back(request);
		}
		}

		TimerThread::Handle TimerThread::MonitorThread::getUniqueHandle_l(
		std::chrono::milliseconds timeout) {
		// To avoid key collisions, advance by 1 tick until the key is unique.
		auto deadline = std::chrono::steady_clock::now() + timeout;
		for (; mMonitorRequests.find(deadline) != mMonitorRequests.end();
		deadline += TimePoint::duration(1))
		deadline += std::chrono::steady_clock::duration(1))
		;
		mMonitorRequests.emplace(deadline, std::move(func));
		mCond.notify_all();
		return deadline;
		}

		// Returns true if cancelled, false if handle doesn't exist.
		// Beware of lock inversion with cancelTask() as the callback
		// is called while holding mMutex.
		bool TimerThread::cancelTask(Handle handle) {
		TimerThread::MonitorThread::MonitorThread(RequestQueue& timeoutQueue)
		: mTimeoutQueue(timeoutQueue)
		, mThread([this] { threadFunc(); }) {
		pthread_setname_np(mThread.native_handle(), "TimerThread");
		pthread_setschedprio(mThread.native_handle(), PRIORITY_URGENT_AUDIO);
		}

		TimerThread::MonitorThread::~MonitorThread() {
		{
		std::lock_guard _l(mMutex);
		return mMonitorRequests.erase(handle) != 0;
		mShouldExit = true;
		mCond.notify_all();
		}
		mThread.join();
		}

		void TimerThread::threadFunc() {
		void TimerThread::MonitorThread::threadFunc() {
		std::unique_lock _l(mMutex);

		while (!mShouldExit) {
		if (!mMonitorRequests.empty()) {
		TimePoint nextDeadline = mMonitorRequests.begin()->first;
		Handle nextDeadline = mMonitorRequests.begin()->first;
		if (nextDeadline < std::chrono::steady_clock::now()) {
		// Deadline expired.
		mMonitorRequests.begin()->second();
		mMonitorRequests.erase(mMonitorRequests.begin());
		// Deadline has expired, handle the request.
		{
		auto node = mMonitorRequests.extract(mMonitorRequests.begin());
		_l.unlock();
		// We add Request to retired queue early so that it can be dumped out.
		mTimeoutQueue.add(std::move(node.mapped().first));
		node.mapped().second(); // Caution: we don't hold lock here - but do we care?
		// this is the timeout case! We will crash soon,
		// maybe before returning.
		// anything left over is released here outside lock.
		}
		// reacquire the lock - if something was added, we loop immediately to check.
		_l.lock();
		continue;
		}
		mCond.wait_until(_l, nextDeadline);
		} else {
		@@ -76,4 +214,35 @@ void TimerThread::threadFunc() {
		}
		}

		} // namespace android
		TimerThread::Handle TimerThread::MonitorThread::add(
		std::shared_ptr<const Request> request, std::function<void()>&& func,
		std::chrono::milliseconds timeout) {
		std::lock_guard _l(mMutex);
		const Handle handle = getUniqueHandle_l(timeout);
		mMonitorRequests.emplace(handle, std::make_pair(std::move(request), std::move(func)));
		mCond.notify_all();
		return handle;
		}

		std::shared_ptr<const TimerThread::Request> TimerThread::MonitorThread::remove(Handle handle) {
		std::unique_lock ul(mMutex);
		const auto it = mMonitorRequests.find(handle);
		if (it == mMonitorRequests.end()) {
		return {};
		}
		std::shared_ptr<const TimerThread::Request> request = std::move(it->second.first);
		std::function<void()> func = std::move(it->second.second);
		mMonitorRequests.erase(it);
		ul.unlock(); // manually release lock here so func is released outside of lock.
		return request;
		}

		void TimerThread::MonitorThread::copyRequests(
		std::vector<std::shared_ptr<const Request>>& requests) const {
		std::lock_guard lg(mMutex);
		for (const auto &[deadline, monitorpair] : mMonitorRequests) {
		requests.emplace_back(monitorpair.first);
		}
		}

		} // namespace android::mediautils

media/utils/include/mediautils/TimeCheck.h

+14 −7

Original line number	Diff line number	Diff line
		@@ -50,27 +50,31 @@ class TimeCheck {
		* destroyed or leaves scope before the timer expires.)
		* float elapsedMs (the elapsed time to this event).
		* The callback when timeout is true will be called on a different thread.
		* Currently this is guaranteed to block the destructor
		* (potential lock inversion warning here) nevertheless
		* it would be safer not to depend on stack contents.
		* This will cancel the callback on the destructor but is not guaranteed
		* to block for callback completion if it is already in progress
		* (for maximum concurrency and reduced deadlock potential), so use proper
		* lifetime analysis (e.g. shared or weak pointers).
		* \param timeoutMs timeout in milliseconds.
		* A zero timeout means no timeout is set -
		* the callback is called only when
		* the TimeCheck object is destroyed or leaves scope.
		* \param crashOnTimeout true if the object issues an abort on timeout.
		*/
		explicit TimeCheck(std::string tag, OnTimerFunc&& onTimer = {},
		uint32_t timeoutMs = kDefaultTimeOutMs, bool crashOnTimeout = true);

		TimeCheck() = default;
		// Remove copy constructors as there should only be one call to the destructor.
		// Move is kept implicitly disabled, but would be logically consistent if enabled.
		TimeCheck(const TimeCheck& other) = delete;
		TimeCheck& operator=(const TimeCheck&) = delete;

		~TimeCheck();
		static std::string toString();
		static void setAudioHalPids(const std::vector<pid_t>& pids);
		static std::vector<pid_t> getAudioHalPids();

		private:
		static TimerThread& getTimeCheckThread();
		static void accessAudioHalPids(std::vector<pid_t>* pids, bool update);

		// Helper class for handling events.
		// The usage here is const safe.
		class TimeCheckHandler {
		@@ -85,11 +89,14 @@ class TimeCheck {
		void onTimeout() const;
		};

		static TimerThread& getTimeCheckThread();
		static void accessAudioHalPids(std::vector<pid_t>* pids, bool update);

		// mTimeCheckHandler is immutable, prefer to be first initialized, last destroyed.
		// Technically speaking, we do not need a shared_ptr here because TimerThread::cancelTask()
		// is mutually exclusive of the callback, but the price paid for lifetime safety is minimal.
		const std::shared_ptr<const TimeCheckHandler> mTimeCheckHandler;
		const TimerThread::Handle mTimerHandle;
		const TimerThread::Handle mTimerHandle = TimerThread::INVALID_HANDLE;
		};

		} // namespace android::mediautils

media/utils/include/mediautils/TimerThread.h

+193 −21

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