Add **Web platform with Emscripten**

Source/Engine/Platform/Web/WebPlatform.h

@@ -0,0 +1,116 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#pragma once
+
+#if PLATFORM_WEB
+
+#include "../Unix/UnixPlatform.h"
+#ifdef __EMSCRIPTEN_PTHREADS__
+#include <pthread.h>
+#endif
+
+/// <summary>
+/// The Web platform implementation and application management utilities.
+/// </summary>
+class FLAXENGINE_API WebPlatform : public UnixPlatform
+{
+public:
+    // [UnixPlatform]
+    FORCE_INLINE static void MemoryBarrier()
+    {
+#ifdef __EMSCRIPTEN_PTHREADS__
+        // Fake a fence with an arbitrary atomic operation (from emscripten_atomic_fence to avoid including it for less header bloat)
+        uint8 temp = 0;
+        __c11_atomic_fetch_or((_Atomic uint8*)&temp, 0, __ATOMIC_SEQ_CST);
+#endif
+    }
+    FORCE_INLINE static void MemoryPrefetch(void const* ptr)
+    {
+        __builtin_prefetch(static_cast<char const*>(ptr));
+    }
+    FORCE_INLINE static int64 InterlockedExchange(int64 volatile* dst, int64 exchange)
+    {
+        return __sync_lock_test_and_set(dst, exchange);
+    }
+    FORCE_INLINE static int32 InterlockedCompareExchange(int32 volatile* dst, int32 exchange, int32 comperand)
+    {
+        return __sync_val_compare_and_swap(dst, comperand, exchange);
+    }
+    FORCE_INLINE static int64 InterlockedCompareExchange(int64 volatile* dst, int64 exchange, int64 comperand)
+    {
+        return __sync_val_compare_and_swap(dst, comperand, exchange);
+    }
+    FORCE_INLINE static int64 InterlockedIncrement(int64 volatile* dst)
+    {
+        return __sync_add_and_fetch(dst, 1);
+    }
+    FORCE_INLINE static int64 InterlockedDecrement(int64 volatile* dst)
+    {
+        return __sync_sub_and_fetch(dst, 1);
+    }
+    FORCE_INLINE static int64 InterlockedAdd(int64 volatile* dst, int64 value)
+    {
+        return __sync_fetch_and_add(dst, value);
+    }
+    FORCE_INLINE static int32 AtomicRead(int32 const volatile* dst)
+    {
+        int32 result;
+        __atomic_load(dst, &result, __ATOMIC_SEQ_CST);
+        return result;
+    }
+    FORCE_INLINE static int64 AtomicRead(int64 const volatile* dst)
+    {
+        int64 result;
+        __atomic_load(dst, &result, __ATOMIC_SEQ_CST);
+        return result;
+    }
+    FORCE_INLINE static void AtomicStore(int32 volatile* dst, int32 value)
+    {
+        __atomic_store(dst, &value, __ATOMIC_SEQ_CST);
+    }
+    FORCE_INLINE static void AtomicStore(int64 volatile* dst, int64 value)
+    {
+        __atomic_store(dst, &value, __ATOMIC_SEQ_CST);
+    }
+    FORCE_INLINE static uint64 GetCurrentThreadID()
+    {
+#ifdef __EMSCRIPTEN_PTHREADS__
+        return (uint64)pthread_self();
+#else
+        return 0;
+#endif
+    }
+    static String GetSystemName();
+    static Version GetSystemVersion();
+    static CPUInfo GetCPUInfo();
+    static MemoryStats GetMemoryStats();
+    static ProcessMemoryStats GetProcessMemoryStats();
+    static void SetThreadPriority(ThreadPriority priority);
+    static void SetThreadAffinityMask(uint64 affinityMask);
+    static void Sleep(int32 milliseconds);
+    static void Yield();
+    static double GetTimeSeconds();
+    static uint64 GetTimeCycles();
+    static void GetSystemTime(int32& year, int32& month, int32& dayOfWeek, int32& day, int32& hour, int32& minute, int32& second, int32& millisecond);
+    static void GetUTCTime(int32& year, int32& month, int32& dayOfWeek, int32& day, int32& hour, int32& minute, int32& second, int32& millisecond);
+#if !BUILD_RELEASE
+    static void Log(const StringView& msg);
+    static bool IsDebuggerPresent();
+#endif
+    static String GetComputerName();
+    static bool GetHasFocus();
+    static String GetMainDirectory();
+    static String GetExecutableFilePath();
+    static Guid GetUniqueDeviceId();
+    static String GetWorkingDirectory();
+    static bool SetWorkingDirectory(const String& path);
+    static bool Init();
+    static void LogInfo();
+    static void Tick();
+    static void Exit();
+    static void* LoadLibrary(const Char* filename);
+    static void FreeLibrary(void* handle);
+    static void* GetProcAddress(void* handle, const char* symbol);
+};
+
+#endif