mtgodot-poc/tests/port/port_file_loader_thread_test.cpp

// EterLib CFileLoaderThread / CThread / Mutex over the Win32Crt kernel-object shims.
// 40250 leaves CResourceManager::ms_loadingThread un-Created (the Create call is commented out), so the
// live path is a static, zero-initialised loader whose Request finds no semaphore and whose Fetch
// never yields; a Created loader reads each request through CEterPackManager on its own thread.
#include "EterLib/StdAfx.h"
#include "EterLib/FileLoaderThread.h"
#include "EterLib/Thread.h"
#include "EterLib/Mutex.h"
#include "EterLib/ResourceManager.h"
#include "EterPack/EterPackManager.h"

#include <atomic>
#include <chrono>
#include <cstdio>
#include <cstring>
#include <thread>
#include <unistd.h>

namespace
{
int failures = 0;

void check(bool ok, const char * name)
{
	if (!ok)
	{
		std::printf("FAIL %s\n", name);
		++failures;
	}
}

CFileLoaderThread s_idleLoader;	// like CResourceManager::ms_loadingThread: static storage, never Created
CFileLoaderThread s_loader;

std::atomic<int> s_counter{0};

class CCountThread : public CThread
{
	public:
		UINT m_setup = 1;
		void * m_arg = NULL;

	protected:
		UINT Setup() override { return m_setup; }
		UINT Execute(void * arg) override
		{
			m_arg = arg;
			++s_counter;
			return 7;
		}
};
}

int main()
{
	// Semaphore: counts, the maximum, timeouts.
	{
		HANDLE sem = CreateSemaphore(NULL, 1, 2, NULL);
		check(sem != NULL, "CreateSemaphore");
		check(!CreateSemaphore(NULL, 3, 2, NULL), "CreateSemaphore initial > maximum");
		check(WaitForSingleObject(sem, 0) == WAIT_OBJECT_0, "semaphore initial count");
		check(WaitForSingleObject(sem, 10) == WAIT_TIMEOUT, "semaphore empty times out");
		LONG previous = -1;
		check(ReleaseSemaphore(sem, 2, &previous) && previous == 0, "ReleaseSemaphore previous count");
		check(!ReleaseSemaphore(sem, 1, NULL), "ReleaseSemaphore past maximum fails");
		check(WaitForSingleObject(sem, 0) == WAIT_OBJECT_0 && WaitForSingleObject(sem, 0) == WAIT_OBJECT_0
			&& WaitForSingleObject(sem, 0) == WAIT_TIMEOUT, "semaphore count kept after failed release");
		check(!ReleaseSemaphore(NULL, 1, NULL), "ReleaseSemaphore NULL handle");
		check(WaitForSingleObject(NULL, 0) == WAIT_FAILED, "WaitForSingleObject NULL handle");

		std::thread waker([sem] {
			std::this_thread::sleep_for(std::chrono::milliseconds(20));
			ReleaseSemaphore(sem, 1, NULL);
		});
		check(WaitForSingleObject(sem, INFINITE) == WAIT_OBJECT_0, "semaphore wakes a waiter");
		waker.join();
		check(CloseHandle(sem) && !CloseHandle(NULL), "CloseHandle");
	}

	// Mutex is recursive (CRITICAL_SECTION); CThread runs Setup then Execute on a new thread.
	{
		Mutex mutex;
		mutex.Lock();
		mutex.Lock();
		mutex.Unlock();
		mutex.Unlock();

		CCountThread thread;
		int arg = 0;
		check(thread.Create(&arg) != 0, "CThread Create");
		for (int i = 0; i < 200 && s_counter.load() == 0; ++i)
			Sleep(5);
		check(s_counter.load() == 1 && thread.m_arg == &arg, "CThread Execute with arg");

		CCountThread noSetup;
		noSetup.m_setup = 0;
		check(noSetup.Create(NULL) != 0, "CThread Create without Setup");
		Sleep(30);
		check(s_counter.load() == 1, "CThread skips Execute when Setup fails");
	}

	char dir[] = "/tmp/mt_fileloader_XXXXXX";
	check(mkdtemp(dir) != NULL, "mkdtemp");
	std::string path = std::string(dir) + "/a.txt";
	FILE * fp = std::fopen(path.c_str(), "wb");
	std::fwrite("hello", 1, 5, fp);
	std::fclose(fp);

	CEterPackManager packs;	// SEARCH_FILE_FIRST: requests read the file from disk
	g_iLoadingDelayTime = 0;

	// 40250 live path: never Created.
	{
		std::string name = path;
		s_idleLoader.Request(name);
		CFileLoaderThread::TData * pData = NULL;
		check(!s_idleLoader.Fetch(&pData), "un-Created loader never completes a request");
		s_idleLoader.Shutdown();
	}

	// Created: requests complete in order with the file contents; a missing file completes empty.
	{
		check(s_loader.Create(NULL) != 0, "CFileLoaderThread Create");
		Sleep(20);	// Setup (the semaphore) runs on the loader thread
		std::string name = path;
		std::string missing = std::string(dir) + "/missing.txt";
		s_loader.Request(name);
		s_loader.Request(missing);

		CFileLoaderThread::TData * got[2] = {};
		int count = 0;
		for (int i = 0; i < 400 && count < 2; ++i)
		{
			if (!s_loader.Fetch(&got[count]))
				Sleep(5);
			else
				++count;
		}
		check(count == 2, "both requests complete");
		if (count == 2)
		{
			check(got[0]->stFileName == path && got[0]->dwSize == 5 && std::memcmp(got[0]->pvBuf, "hello", 5) == 0,
				"request loaded through CEterPackManager");
			check(got[1]->dwSize == 0 && got[1]->pvBuf == NULL, "missing file completes empty");
			for (CFileLoaderThread::TData * pData : got)
			{
				delete [] ((char *) pData->pvBuf);
				delete pData;
			}
		}
		s_loader.Shutdown();
	}

	unlink(path.c_str());
	rmdir(dir);
	if (!failures)
		std::printf("ok\n");
	return failures ? 1 : 0;
}