Fix some threading things and add additional thread unittests

- Fix thread name reset on start()
- Fully reset thread state on kill()
- Add unittests to check for correct object states under various circumstances

src/threading/thread.cpp

@@ -88,16 +88,13 @@ DEALINGS IN THE SOFTWARE.
 Thread::Thread(const std::string &name) :
 	m_name(name),
 	m_retval(NULL),
+	m_joinable(false),
 	m_request_stop(false),
 	m_running(false)
 {
 #ifdef _AIX
 	m_kernel_thread_id = -1;
 #endif
-
-#if USE_CPP11_THREADS
-	m_thread_obj = NULL;
-#endif
 }
 
 
@@ -109,12 +106,12 @@ Thread::~Thread()
 
 bool Thread::start()
 {
-	MutexAutoLock lock(m_continue_mutex);
+	MutexAutoLock lock(m_mutex);
 
 	if (m_running)
 		return false;
 
-	cleanup();
+	m_request_stop = false;
 
 #if USE_CPP11_THREADS
 
@@ -145,6 +142,8 @@ bool Thread::start()
 	while (!m_running)
 		sleep_ms(1);
 
+	m_joinable = true;
+
 	return true;
 }
 
@@ -156,21 +155,30 @@ bool Thread::stop()
 }
 
 
-void Thread::wait()
+bool Thread::wait()
 {
-	if (!m_running)
-		return;
+	MutexAutoLock lock(m_mutex);
+
+	if (!m_joinable)
+		return false;
 
 #if USE_CPP11_THREADS
 
 	m_thread_obj->join();
 
+	delete m_thread_obj;
+	m_thread_obj = NULL;
+
 #elif USE_WIN_THREADS
 
 	int ret = WaitForSingleObject(m_thread_handle, INFINITE);
 	assert(ret == WAIT_OBJECT_0);
 	UNUSED(ret);
 
+	CloseHandle(m_thread_handle);
+	m_thread_handle = NULL;
+	m_thread_id = -1;
+
 #elif USE_POSIX_THREADS
 
 	int ret = pthread_join(m_thread_handle, NULL);
@@ -180,8 +188,8 @@ void Thread::wait()
 #endif
 
 	assert(m_running == false);
-
-	return;
+	m_joinable = false;
+	return true;
 }
 
 
@@ -192,10 +200,12 @@ bool Thread::kill()
 		return false;
 	}
 
+	m_running = false;
+
 #ifdef _WIN32
 	TerminateThread(m_thread_handle, 0);
+	CloseHandle(m_thread_handle);
 #else
-
 	// We need to pthread_kill instead on Android since NDKv5's pthread
 	// implementation is incomplete.
 # ifdef __ANDROID__
@@ -203,42 +213,17 @@ bool Thread::kill()
 # else
 	pthread_cancel(m_thread_handle);
 # endif
-
 	wait();
 #endif
 
-	cleanup();
+	m_retval       = NULL;
+	m_joinable     = false;
+	m_request_stop = false;
 
 	return true;
 }
 
 
-void Thread::cleanup()
-{
-#if USE_CPP11_THREADS
-
-	delete m_thread_obj;
-	m_thread_obj = NULL;
-
-#elif USE_WIN_THREADS
-
-	CloseHandle(m_thread_handle);
-	m_thread_handle = NULL;
-	m_thread_id = -1;
-
-#elif USE_POSIX_THREADS
-
-	// Can't do any cleanup for pthreads
-
-#endif
-
-	m_name         = "";
-	m_retval       = NULL;
-	m_running      = false;
-	m_request_stop = false;
-}
-
-
 bool Thread::getReturnValue(void **ret)
 {
 	if (m_running)
@@ -256,11 +241,11 @@ bool Thread::isCurrentThread()
 
 
 #if USE_CPP11_THREADS || USE_POSIX_THREADS
-	void *(Thread::threadProc)(void *param)
+void *Thread::threadProc(void *param)
 #elif defined(_WIN32_WCE)
-	DWORD (Thread::threadProc)(LPVOID param)
+DWORD Thread::threadProc(LPVOID param)
 #elif defined(_WIN32)
-	DWORD WINAPI (Thread::threadProc)(LPVOID param)
+DWORD WINAPI Thread::threadProc(LPVOID param)
 #endif
 {
 	Thread *thr = (Thread *)param;

src/threading/thread.h

@@ -81,9 +81,10 @@ public:
 	/*
 	 * Waits for thread to finish.
 	 * Note:  This does not stop a thread, you have to do this on your own.
-	 * Returns immediately if the thread is not started.
+	 * Returns false immediately if the thread is not started or has been waited
+	 * on before.
 	 */
-	void wait();
+	bool wait();
 
 	/*
 	 * Returns true if the calling thread is this Thread object.
@@ -140,15 +141,14 @@ protected:
 
 private:
 	void *m_retval;
+	bool m_joinable;
 	Atomic<bool> m_request_stop;
 	Atomic<bool> m_running;
-	Mutex m_continue_mutex;
+	Mutex m_mutex;
 
 	threadid_t m_thread_id;
 	threadhandle_t m_thread_handle;
 
-	void cleanup();
-
 	static ThreadStartFunc threadProc;
 
 #ifdef _AIX

src/threads.h

@@ -58,11 +58,11 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 // ThreadStartFunc
 //
 #if USE_CPP11_THREADS || USE_POSIX_THREADS
-	typedef void *(ThreadStartFunc)(void *param);
+	typedef void *ThreadStartFunc(void *param);
 #elif defined(_WIN32_WCE)
-	typedef DWORD (ThreadStartFunc)(LPVOID param);
+	typedef DWORD ThreadStartFunc(LPVOID param);
 #elif defined(_WIN32)
-	typedef DWORD WINAPI (ThreadStartFunc)(LPVOID param);
+	typedef DWORD WINAPI ThreadStartFunc(LPVOID param);
 #endif
 
 

src/unittest/test_threading.cpp

@@ -28,26 +28,122 @@ class TestThreading : public TestBase {
 public:
 	TestThreading() { TestManager::registerTestModule(this); }
 	const char *getName() { return "TestThreading"; }
-	void runTests(IGameDef *);
+	void runTests(IGameDef *gamedef);
+
+	void testStartStopWait();
+	void testThreadKill();
 	void testAtomicSemaphoreThread();
 };
 
 static TestThreading g_test_instance;
 
-void TestThreading::runTests(IGameDef *)
+void TestThreading::runTests(IGameDef *gamedef)
 {
+	TEST(testStartStopWait);
+	TEST(testThreadKill);
 	TEST(testAtomicSemaphoreThread);
 }
 
-
-class AtomicTestThread : public Thread
+class SimpleTestThread : public Thread {
+public:
+	SimpleTestThread(unsigned int interval) :
+		Thread("SimpleTest"),
+		m_interval(interval)
 	{
+	}
+
+private:
+	void *run()
+	{
+		void *retval = this;
+
+		if (isCurrentThread() == false)
+			retval = (void *)0xBAD;
+
+		while (!stopRequested())
+			sleep_ms(m_interval);
+
+		return retval;
+	}
+
+	unsigned int m_interval;
+};
+
+void TestThreading::testStartStopWait()
+{
+	void *thread_retval;
+	SimpleTestThread *thread = new SimpleTestThread(25);
+
+	// Try this a couple times, since a Thread should be reusable after waiting
+	for (size_t i = 0; i != 5; i++) {
+		// Can't wait() on a joined, stopped thread
+		UASSERT(thread->wait() == false);
+
+		// start() should work the first time, but not the second.
+		UASSERT(thread->start() == true);
+		UASSERT(thread->start() == false);
+
+		UASSERT(thread->isRunning() == true);
+		UASSERT(thread->isCurrentThread() == false);
+
+		// Let it loop a few times...
+		sleep_ms(70);
+
+		// It's still running, so the return value shouldn't be available to us.
+		UASSERT(thread->getReturnValue(&thread_retval) == false);
+
+		// stop() should always succeed
+		UASSERT(thread->stop() == true);
+
+		// wait() only needs to wait the first time - the other two are no-ops.
+		UASSERT(thread->wait() == true);
+		UASSERT(thread->wait() == false);
+		UASSERT(thread->wait() == false);
+
+		// Now that the thread is stopped, we should be able to get the
+		// return value, and it should be the object itself.
+		thread_retval = NULL;
+		UASSERT(thread->getReturnValue(&thread_retval) == true);
+		UASSERT(thread_retval == thread);
+	}
+
+	delete thread;
+}
+
+
+void TestThreading::testThreadKill()
+{
+	SimpleTestThread *thread = new SimpleTestThread(300);
+
+	UASSERT(thread->start() == true);
+
+	// kill()ing is quite violent, so let's make sure our victim is sleeping
+	// before we do this... so we don't corrupt the rest of the program's state
+	sleep_ms(100);
+	UASSERT(thread->kill() == true);
+
+	// The state of the thread object should be reset if all went well
+	UASSERT(thread->isRunning() == false);
+	UASSERT(thread->start() == true);
+	UASSERT(thread->stop() == true);
+	UASSERT(thread->wait() == true);
+
+	// kill() after already waiting should fail.
+	UASSERT(thread->kill() == false);
+
+	delete thread;
+}
+
+
+class AtomicTestThread : public Thread {
 public:
 	AtomicTestThread(Atomic<u32> &v, Semaphore &trigger) :
 		Thread("AtomicTest"),
 		val(v),
 		trigger(trigger)
-	{}
+	{
+	}
+
 private:
 	void *run()
 	{
@@ -56,6 +152,7 @@ private:
 			++val;
 		return NULL;
 	}
+
 	Atomic<u32> &val;
 	Semaphore &trigger;
 };