Merge "Fix timeouts for android::base::WaitForProperty*" am: 57d78354d6 am: f30abecf3c (ff21ab5a) · Commits · e / os / android_system_core

base/include/android-base/properties.h

+4 −5

Original line number	Diff line number	Diff line
		@@ -62,15 +62,14 @@ bool SetProperty(const std::string& key, const std::string& value);
		// Waits for the system property `key` to have the value `expected_value`.
		// Times out after `relative_timeout`.
		// Returns true on success, false on timeout.
		bool WaitForProperty(const std::string& key,
		const std::string& expected_value,
		std::chrono::milliseconds relative_timeout);
		bool WaitForProperty(const std::string& key, const std::string& expected_value,
		std::chrono::milliseconds relative_timeout = std::chrono::milliseconds::max());

		// Waits for the system property `key` to be created.
		// Times out after `relative_timeout`.
		// Returns true on success, false on timeout.
		bool WaitForPropertyCreation(const std::string& key,
		std::chrono::milliseconds relative_timeout);
		bool WaitForPropertyCreation(const std::string& key, std::chrono::milliseconds relative_timeout =
		std::chrono::milliseconds::max());

		} // namespace base
		} // namespace android

base/properties.cpp

+15 −18

Original line number	Diff line number	Diff line
		@@ -101,22 +101,24 @@ static void WaitForPropertyCallback(void* data_ptr, const char, const char val
		}

		// TODO: chrono_utils?
		static void DurationToTimeSpec(timespec& ts, std::chrono::nanoseconds d) {
		static void DurationToTimeSpec(timespec& ts, const std::chrono::milliseconds d) {
		auto s = std::chrono::duration_cast<std::chrono::seconds>(d);
		auto ns = std::chrono::duration_cast<std::chrono::nanoseconds>(d - s);
		ts.tv_sec = s.count();
		ts.tv_nsec = ns.count();
		}

		// TODO: boot_clock?
		using AbsTime = std::chrono::time_point<std::chrono::steady_clock>;

		static void UpdateTimeSpec(timespec& ts,
		const AbsTime& timeout) {
		static void UpdateTimeSpec(timespec& ts, std::chrono::milliseconds relative_timeout,
		const AbsTime& start_time) {
		auto now = std::chrono::steady_clock::now();
		auto remaining_timeout = std::chrono::duration_cast<std::chrono::nanoseconds>(timeout - now);
		if (remaining_timeout < 0ns) {
		auto time_elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(now - start_time);
		if (time_elapsed >= relative_timeout) {
		ts = { 0, 0 };
		} else {
		auto remaining_timeout = relative_timeout - time_elapsed;
		DurationToTimeSpec(ts, remaining_timeout);
		}
		}
		@@ -127,11 +129,7 @@ static void UpdateTimeSpec(timespec& ts,
		// Returns nullptr on timeout.
		static const prop_info* WaitForPropertyCreation(const std::string& key,
		const std::chrono::milliseconds& relative_timeout,
		AbsTime& absolute_timeout) {
		// TODO: boot_clock?
		auto now = std::chrono::steady_clock::now();
		absolute_timeout = now + relative_timeout;

		const AbsTime& start_time) {
		// Find the property's prop_info*.
		const prop_info* pi;
		unsigned global_serial = 0;
		@@ -139,17 +137,16 @@ static const prop_info* WaitForPropertyCreation(const std::string& key,
		// The property doesn't even exist yet.
		// Wait for a global change and then look again.
		timespec ts;
		UpdateTimeSpec(ts, absolute_timeout);
		UpdateTimeSpec(ts, relative_timeout, start_time);
		if (!__system_property_wait(nullptr, global_serial, &global_serial, &ts)) return nullptr;
		}
		return pi;
		}

		bool WaitForProperty(const std::string& key,
		const std::string& expected_value,
		bool WaitForProperty(const std::string& key, const std::string& expected_value,
		std::chrono::milliseconds relative_timeout) {
		AbsTime absolute_timeout;
		const prop_info* pi = WaitForPropertyCreation(key, relative_timeout, absolute_timeout);
		auto start_time = std::chrono::steady_clock::now();
		const prop_info* pi = WaitForPropertyCreation(key, relative_timeout, start_time);
		if (pi == nullptr) return false;

		WaitForPropertyData data;
		@@ -162,7 +159,7 @@ bool WaitForProperty(const std::string& key,
		if (data.done) return true;

		// It didn't, so wait for the property to change before checking again.
		UpdateTimeSpec(ts, absolute_timeout);
		UpdateTimeSpec(ts, relative_timeout, start_time);
		uint32_t unused;
		if (!__system_property_wait(pi, data.last_read_serial, &unused, &ts)) return false;
		}
		@@ -170,8 +167,8 @@ bool WaitForProperty(const std::string& key,

		bool WaitForPropertyCreation(const std::string& key,
		std::chrono::milliseconds relative_timeout) {
		AbsTime absolute_timeout;
		return (WaitForPropertyCreation(key, relative_timeout, absolute_timeout) != nullptr);
		auto start_time = std::chrono::steady_clock::now();
		return (WaitForPropertyCreation(key, relative_timeout, start_time) != nullptr);
		}

		} // namespace base

base/properties_test.cpp

+32 −0

Original line number	Diff line number	Diff line
		@@ -151,6 +151,38 @@ TEST(properties, WaitForProperty_timeout) {
		ASSERT_LT(std::chrono::duration_cast<std::chrono::milliseconds>(t1 - t0), 600ms);
		}

		TEST(properties, WaitForProperty_MaxTimeout) {
		std::atomic<bool> flag{false};
		std::thread thread([&]() {
		android::base::SetProperty("debug.libbase.WaitForProperty_test", "a");
		while (!flag) std::this_thread::yield();
		std::this_thread::sleep_for(500ms);
		android::base::SetProperty("debug.libbase.WaitForProperty_test", "b");
		});

		ASSERT_TRUE(android::base::WaitForProperty("debug.libbase.WaitForProperty_test", "a", 1s));
		flag = true;
		// Test that this does not immediately return false due to overflow issues with the timeout.
		ASSERT_TRUE(android::base::WaitForProperty("debug.libbase.WaitForProperty_test", "b"));
		thread.join();
		}

		TEST(properties, WaitForProperty_NegativeTimeout) {
		std::atomic<bool> flag{false};
		std::thread thread([&]() {
		android::base::SetProperty("debug.libbase.WaitForProperty_test", "a");
		while (!flag) std::this_thread::yield();
		std::this_thread::sleep_for(500ms);
		android::base::SetProperty("debug.libbase.WaitForProperty_test", "b");
		});

		ASSERT_TRUE(android::base::WaitForProperty("debug.libbase.WaitForProperty_test", "a", 1s));
		flag = true;
		// Assert that this immediately returns with a negative timeout
		ASSERT_FALSE(android::base::WaitForProperty("debug.libbase.WaitForProperty_test", "b", -100ms));
		thread.join();
		}

		TEST(properties, WaitForPropertyCreation) {
		std::thread thread([&]() {
		std::this_thread::sleep_for(100ms);