correct thread model for unit test timeouts

it seems that child threads can't terminate the whole process,
so we need to instead use a worker thread and make the
main thread the timer / return thread.

src/game.cpp

@@ -48,6 +48,10 @@
 #include <boost/iostreams/filter/bzip2.hpp>
 #include <boost/iostreams/filter/gzip.hpp>
 
+#include <SDL.h>
+#include <SDL_thread.h>
+
+
 #ifdef HAVE_VISUAL_LEAK_DETECTOR
 #include "vld.h"
 #endif
@@ -406,6 +410,26 @@ static void init_locale() {
 	textdomain (PACKAGE);
 }
 
+static SDL_sem * worker_sem;
+/**
+ * Function used by worker thread to perform unit test with timeout.
+ */
+static int run_unit_test (void * data){
+	std::pair<game_controller*, int*> * mydata = (std::pair<game_controller*, int*> *) data;
+	if (SDL_SemWait(worker_sem) == -1) {
+		std::cerr << "Worker failed to lock worker semaphore!" << std::endl;
+	}
+	game_controller * game = mydata->first; 
+	int * return_value = mydata->second;
+	int ret_val = game->unit_test();
+	*return_value = ret_val;
+
+	if (SDL_SemPost(worker_sem) == -1) {
+		std::cerr << "Worker failed to unlock worker semaphore after working!" << std::endl;
+	}
+	return ret_val;
+}
+
 /**
  * Setups the game environment and enters
  * the titlescreen or game loops.
@@ -522,9 +546,41 @@ static int do_gameloop(int argc, char** argv)
 		loadscreen_manager.reset();
 
 		if(cmdline_opts.unit_test) {
-			int worker_result = game->unit_test();
-			std::cout << ((worker_result == 0) ? "PASS TEST: " : "FAIL TEST: ") << *cmdline_opts.unit_test << std::endl;
-			return worker_result;
+			if(cmdline_opts.timeout && *cmdline_opts.timeout > 0) {
+				int worker_result = 2; //Default timeout return value if worker fails to return
+				worker_sem = SDL_CreateSemaphore(1);
+				if (worker_sem == NULL) {
+					std::cerr << "Failed to create a semaphore for timeout worker thread!" << std::endl;
+					std::cout << "FAIL TEST (TIMEOUT): " << *cmdline_opts.unit_test << std::endl;
+					return 2;
+				}
+
+				std::pair<game_controller *, int *> data(&(*game), &worker_result);
+				SDL_Thread *worker = SDL_CreateThread(&run_unit_test, &data);
+
+				std::cerr << "Setting timer for " << *cmdline_opts.timeout << " ms." << std::endl;
+				int wait_result = SDL_SemWaitTimeout(worker_sem, *cmdline_opts.timeout);
+				if (wait_result == 0) {
+					SDL_SemPost(worker_sem);
+					SDL_DestroySemaphore(worker_sem);
+					return worker_result;
+				} else if (wait_result == -1) {
+					SDL_KillThread(worker); //don't want worker to keep running when game goes out of scope
+					std::cerr << "Error in SemWaitTimeout!" << std::endl;
+					std::cout << ("FAIL TEST (TIMEOUT): ") << *cmdline_opts.unit_test << std::endl;
+					return 2;
+				} else {
+					SDL_KillThread(worker); //don't want worker to keep running when game goes out of scope
+					std::cerr << "Test timed out!" << std::endl;
+					std::cout << ("FAIL TEST (TIMEOUT): ") << *cmdline_opts.unit_test << std::endl;
+					return 2;
+				}
+			}
+			else {
+				int worker_result = game->unit_test();
+				std::cout << ((worker_result == 0) ? "PASS TEST: " : "FAIL TEST: ") << *cmdline_opts.unit_test << std::endl;
+				return worker_result;
+			}
 		}
 
 		if(game->play_test() == false) {

src/game_controller.cpp

@@ -249,9 +249,6 @@ game_controller::game_controller(const commandline_options& cmdline_opts, const
 	{
 		if (!cmdline_opts_.unit_test->empty()) {
 			test_scenario_ = *cmdline_opts_.unit_test;
-			if (cmdline_opts_.timeout) {
-				timeout = *cmdline_opts_.timeout;
-			}		
 		}
 
 	}
@@ -444,14 +441,6 @@ bool game_controller::play_test()
 	return false;
 }
 
-unsigned int unit_test_timeout(unsigned int, void* param)
-{
-	std::string * scen = (std::string *)param;
-	std::cerr << "Test timed out!" << std::endl;
-	std::cout << ("FAIL TEST (TIMEOUT): ") << *scen << std::endl;
-	exit(2);
-}
-
 // Same as play_test except that we return the results of play_game.
 int game_controller::unit_test()
 {
@@ -472,11 +461,6 @@ int game_controller::unit_test()
 	resources::config_manager->
 		load_game_config_for_game(state_.classification());
 
-	if(cmdline_opts_.timeout && timeout > 0) {
-		std::cerr << "Adding timer for " << timeout << " ms." << std::endl;
-		SDL_AddTimer(timeout, unit_test_timeout, & test_scenario_);
-	}
-
 	try {
 		LEVEL_RESULT res = play_game(disp(),state_,resources::config_manager->game_config());
 		return ((res == VICTORY || res == NONE) ? 0 : 1);
@@ -485,8 +469,6 @@ int game_controller::unit_test()
 	}
 }
 
-#undef Uint32
-
 bool game_controller::play_screenshot_mode()
 {
 	if(!cmdline_opts_.screenshot) {

src/game_controller.hpp

@@ -107,7 +107,6 @@ class game_controller
 	resize_monitor resize_monitor_;
 
 	std::string test_scenario_;
-	unsigned int timeout;
 
 	std::string screenshot_map_, screenshot_filename_;