UnrealEngineUWP/Engine/Source/Developer/TargetPlatform/Private/TargetPlatformManagerModule.cpp

// Copyright 1998-2017 Epic Games, Inc. All Rights Reserved.

#include "CoreMinimal.h"
#include "HAL/FileManager.h"
#include "Misc/CommandLine.h"
#include "Misc/Paths.h"
#include "Misc/OutputDeviceRedirector.h"
#include "Templates/ScopedPointer.h"
#include "Stats/Stats.h"
#include "Misc/ScopedSlowTask.h"
#include "Misc/MonitoredProcess.h"
#include "Modules/ModuleManager.h"
#include "Interfaces/ITargetPlatform.h"
#include "Interfaces/ITargetPlatformModule.h"
#include "Interfaces/ITargetPlatformManagerModule.h"
#include "Interfaces/IAudioFormat.h"
#include "Interfaces/IAudioFormatModule.h"
#include "Interfaces/IShaderFormat.h"
#include "Interfaces/IShaderFormatModule.h"
#include "Interfaces/ITextureFormat.h"
#include "Interfaces/ITextureFormatModule.h"
#include "PlatformInfo.h"
#include "DesktopPlatformModule.h"

#if WITH_PHYSX
#include "IPhysXCooking.h"
#include "IPhysXCookingModule.h"
#endif // WITH_PHYSX

DEFINE_LOG_CATEGORY_STATIC(LogTargetPlatformManager, Log, All);


// autosdks only function properly on windows right now.
#if !IS_MONOLITHIC && (PLATFORM_WINDOWS)
	#define AUTOSDKS_ENABLED 1
#else
	#define AUTOSDKS_ENABLED 0
#endif


/**
 * Module for the target platform manager
 */
class FTargetPlatformManagerModule
	: public ITargetPlatformManagerModule
{
public:

	/** Default constructor. */
	FTargetPlatformManagerModule()
		: bRestrictFormatsToRuntimeOnly(false)
		, bForceCacheUpdate(true)
		, bIgnoreFirstDelegateCall(true)
	{
#if AUTOSDKS_ENABLED		
		
		// AutoSDKs only enabled if UE_SDKS_ROOT is set.
		if (IsAutoSDKsEnabled())
		{					
			DECLARE_SCOPE_CYCLE_COUNTER( TEXT( "FTargetPlatformManagerModule.StartAutoSDK" ), STAT_FTargetPlatformManagerModule_StartAutoSDK, STATGROUP_TargetPlatform );

			// amortize UBT cost by calling it once for all platforms, rather than once per platform.
			if (FParse::Param(FCommandLine::Get(), TEXT("Multiprocess"))==false)
			{
				FString UBTParams(TEXT("-autosdkonly"));
				int32 UBTReturnCode = -1;
				FString UBTOutput;
				if (!FDesktopPlatformModule::Get()->InvokeUnrealBuildToolSync(UBTParams, *GLog, true, UBTReturnCode, UBTOutput))
				{
					UE_LOG(LogTargetPlatformManager, Fatal, TEXT("Failed to run UBT to check SDK status!"));
				}
			}

			// we have to setup our local environment according to AutoSDKs or the ITargetPlatform's IsSDkInstalled calls may fail
			// before we get a change to setup for a given platform.  Use the platforminfo list to avoid any kind of interdependency.
			int32 NumPlatforms;
			const PlatformInfo::FPlatformInfo* PlatformInfoArray = PlatformInfo::GetPlatformInfoArray(NumPlatforms);
			for (int32 i = 0; i < NumPlatforms; ++i)
			{
				const PlatformInfo::FPlatformInfo& PlatformInfo = PlatformInfoArray[i];
				if (PlatformInfo.AutoSDKPath.Len() > 0)
				{
					SetupAndValidateAutoSDK(PlatformInfo.AutoSDKPath);
				}
			}
		}
#endif

		SetupSDKStatus();
		//GetTargetPlatforms(); redudant with next call
		GetActiveTargetPlatforms();
		GetAudioFormats();
		GetTextureFormats();
		GetShaderFormats();

		bForceCacheUpdate = false;

		FModuleManager::Get().OnModulesChanged().AddRaw(this, &FTargetPlatformManagerModule::ModulesChangesCallback);
	}

	/** Destructor. */
	virtual ~FTargetPlatformManagerModule()
	{
		FModuleManager::Get().OnModulesChanged().RemoveAll(this);
	}

public:

	// ITargetPlatformManagerModule interface

	virtual void Invalidate() override
	{
		bForceCacheUpdate = true;

		SetupSDKStatus();
		//GetTargetPlatforms(); redudant with next call
		GetActiveTargetPlatforms();
		GetAudioFormats();
		GetTextureFormats();
		GetShaderFormats();

		bForceCacheUpdate = false;
	}

	virtual const TArray<ITargetPlatform*>& GetTargetPlatforms() override
	{
		if (Platforms.Num() == 0 || bForceCacheUpdate)
		{
			DiscoverAvailablePlatforms();
		}

		return Platforms;
	}

	virtual ITargetDevicePtr FindTargetDevice(const FTargetDeviceId& DeviceId) override
	{
		ITargetPlatform* Platform = FindTargetPlatform(DeviceId.GetPlatformName());

		if (Platform != nullptr)
		{
			return Platform->GetDevice(DeviceId);
		}

		return nullptr;
	}

	virtual ITargetPlatform* FindTargetPlatform(FString Name) override
	{
		const TArray<ITargetPlatform*>& TargetPlatforms = GetTargetPlatforms();	
		
		for (int32 Index = 0; Index < TargetPlatforms.Num(); Index++)
		{
			if (TargetPlatforms[Index]->PlatformName() == Name)
			{
				return TargetPlatforms[Index];
			}
		}

		return nullptr;
	}

	virtual const TArray<ITargetPlatform*>& GetCookingTargetPlatforms() override
	{
		static bool bInitialized = false;
		static TArray<ITargetPlatform*> Results;

		if ( !bInitialized || bForceCacheUpdate )
		{
			Results = GetActiveTargetPlatforms();

			FString PlatformStr;
			if (FParse::Value(FCommandLine::Get(), TEXT("TARGETPLATFORM="), PlatformStr))
			{
				if (PlatformStr == TEXT("None"))
				{
					Results = Platforms;
				}
			}
			else
			{
				Results = Platforms;
			}
		}

		return Results;
	}

	virtual const TArray<ITargetPlatform*>& GetActiveTargetPlatforms() override
	{
		static bool bInitialized = false;
		static TArray<ITargetPlatform*> Results;

		if (!bInitialized || bForceCacheUpdate)
		{
			bInitialized = true;

			Results.Empty(Results.Num());

			const TArray<ITargetPlatform*>& TargetPlatforms = GetTargetPlatforms();	

			FString PlatformStr;

			if (FParse::Value(FCommandLine::Get(), TEXT("TARGETPLATFORM="), PlatformStr))
			{
				if (PlatformStr == TEXT("None"))
				{
				}
				else if (PlatformStr == TEXT("All"))
				{
					Results = TargetPlatforms;
				}
				else
				{
					TArray<FString> PlatformNames;

					PlatformStr.ParseIntoArray(PlatformNames, TEXT("+"), true);

					// for nicer user response
					FString AvailablePlatforms;

					for (int32 Index = 0; Index < TargetPlatforms.Num(); Index++)
					{
						if (PlatformNames.Contains(TargetPlatforms[Index]->PlatformName()))
						{							
							Results.Add(TargetPlatforms[Index]);						
						}

						if(!AvailablePlatforms.IsEmpty())
						{
							AvailablePlatforms += TEXT(", ");
						}
						AvailablePlatforms += TargetPlatforms[Index]->PlatformName();
					}

					if (Results.Num() == 0)
					{
						// An invalid platform was specified...
						// Inform the user and exit.
						UE_LOG(LogTargetPlatformManager, Error, TEXT("Invalid target platform specified (%s). Available = { %s } "), *PlatformStr, *AvailablePlatforms);
						UE_LOG(LogTargetPlatformManager, Fatal, TEXT("Invalid target platform specified (%s). Available = { %s } "), *PlatformStr, *AvailablePlatforms);
					}
				}
			}
			else
			{
				// if there is no argument, use the current platform and only build formats that are actually needed to run.
				bRestrictFormatsToRuntimeOnly = true;

				for (int32 Index = 0; Index < TargetPlatforms.Num(); Index++)
				{
					if (TargetPlatforms[Index]->IsRunningPlatform())
					{						
						Results.Add(TargetPlatforms[Index]);					
					}
				}
			}

			if (!Results.Num())
			{
				UE_LOG(LogTargetPlatformManager, Display, TEXT("Not building assets for any platform."));
			}
			else
			{
				for (int32 Index = 0; Index < Results.Num(); Index++)
				{
					UE_LOG(LogTargetPlatformManager, Display, TEXT("Building Assets For %s"), *Results[Index]->PlatformName());
				}
			}
		}

		return Results;
	}

	virtual bool RestrictFormatsToRuntimeOnly() override
	{
		GetActiveTargetPlatforms(); // make sure this is initialized

		return bRestrictFormatsToRuntimeOnly;
	}

	virtual ITargetPlatform* GetRunningTargetPlatform() override
	{
		static bool bInitialized = false;
		static ITargetPlatform* Result = nullptr;

		if (!bInitialized || bForceCacheUpdate)
		{
			bInitialized = true;
			Result = nullptr;

			const TArray<ITargetPlatform*>& TargetPlatforms = GetTargetPlatforms();	

			for (int32 Index = 0; Index < TargetPlatforms.Num(); Index++)
			{
				if (TargetPlatforms[Index]->IsRunningPlatform())
				{
					 // we should not have two running platforms
					checkf((Result == nullptr),
						TEXT("Found multiple running platforms.\n\t%s\nand\n\t%s"),
						*Result->PlatformName(),
						*TargetPlatforms[Index]->PlatformName()
						);
					Result = TargetPlatforms[Index];
				}
			}
		}

		return Result;
	}

	virtual const TArray<const IAudioFormat*>& GetAudioFormats() override
	{
		static bool bInitialized = false;
		static TArray<const IAudioFormat*> Results;

		if (!bInitialized || bForceCacheUpdate)
		{
			bInitialized = true;
			Results.Empty(Results.Num());

			TArray<FName> Modules;

			FModuleManager::Get().FindModules(TEXT("*AudioFormat*"), Modules);

			if (!Modules.Num())
			{
				UE_LOG(LogTargetPlatformManager, Error, TEXT("No target audio formats found!"));
			}

			for (int32 Index = 0; Index < Modules.Num(); Index++)
			{
				IAudioFormatModule* Module = FModuleManager::LoadModulePtr<IAudioFormatModule>(Modules[Index]);
				if (Module)
				{
					IAudioFormat* Format = Module->GetAudioFormat();
					if (Format != nullptr)
					{
						Results.Add(Format);
					}
				}
			}
		}

		return Results;
	}

	virtual const IAudioFormat* FindAudioFormat(FName Name) override
	{
		const TArray<const IAudioFormat*>& AudioFormats = GetAudioFormats();

		for (int32 Index = 0; Index < AudioFormats.Num(); Index++)
		{
			TArray<FName> Formats;

			AudioFormats[Index]->GetSupportedFormats(Formats);

			for (int32 FormatIndex = 0; FormatIndex < Formats.Num(); FormatIndex++)
			{
				if (Formats[FormatIndex] == Name)
				{
					return AudioFormats[Index];
				}
			}
		}

		return nullptr;
	}

	virtual const TArray<const ITextureFormat*>& GetTextureFormats() override
	{
		static bool bInitialized = false;
		static TArray<const ITextureFormat*> Results;

		if (!bInitialized || bForceCacheUpdate)
		{
			bInitialized = true;
			Results.Empty(Results.Num());

			TArray<FName> Modules;

			FModuleManager::Get().FindModules(TEXT("*TextureFormat*"), Modules);

			if (!Modules.Num())
			{
				UE_LOG(LogTargetPlatformManager, Error, TEXT("No target texture formats found!"));
			}

			for (int32 Index = 0; Index < Modules.Num(); Index++)
			{
				ITextureFormatModule* Module = FModuleManager::LoadModulePtr<ITextureFormatModule>(Modules[Index]);
				if (Module)
				{
					ITextureFormat* Format = Module->GetTextureFormat();
					if (Format != nullptr)
					{
						Results.Add(Format);
					}
				}
			}
		}

		return Results;
	}

	virtual const ITextureFormat* FindTextureFormat(FName Name) override
	{
		const TArray<const ITextureFormat*>& TextureFormats = GetTextureFormats();

		for (int32 Index = 0; Index < TextureFormats.Num(); Index++)
		{
			TArray<FName> Formats;

			TextureFormats[Index]->GetSupportedFormats(Formats);

			for (int32 FormatIndex = 0; FormatIndex < Formats.Num(); FormatIndex++)
			{
				if (Formats[FormatIndex] == Name)
				{
					return TextureFormats[Index];
				}
			}
		}

		return nullptr;
	}

	virtual const TArray<const IShaderFormat*>& GetShaderFormats() override
	{
		static bool bInitialized = false;
		static TArray<const IShaderFormat*> Results;

		if (!bInitialized || bForceCacheUpdate)
		{
			bInitialized = true;
			Results.Empty(Results.Num());

			TArray<FName> Modules;

			FModuleManager::Get().FindModules(SHADERFORMAT_MODULE_WILDCARD, Modules);

			if (!Modules.Num())
			{
				UE_LOG(LogTargetPlatformManager, Error, TEXT("No target shader formats found!"));
			}

			for (int32 Index = 0; Index < Modules.Num(); Index++)
			{
				IShaderFormatModule* Module = FModuleManager::LoadModulePtr<IShaderFormatModule>(Modules[Index]);
				if (Module)
				{
					IShaderFormat* Format = Module->GetShaderFormat();
					if (Format != nullptr)
					{
						Results.Add(Format);
					}
				}
			}
		}
		return Results;
	}

	virtual const IShaderFormat* FindShaderFormat(FName Name) override
	{
		const TArray<const IShaderFormat*>& ShaderFormats = GetShaderFormats();	

		for (int32 Index = 0; Index < ShaderFormats.Num(); Index++)
		{
			TArray<FName> Formats;
			
			ShaderFormats[Index]->GetSupportedFormats(Formats);
		
			for (int32 FormatIndex = 0; FormatIndex < Formats.Num(); FormatIndex++)
			{
				if (Formats[FormatIndex] == Name)
				{
					return ShaderFormats[Index];
				}
			}
		}

		return nullptr;
	}

	virtual uint32 ShaderFormatVersion(FName Name) override
	{
		static TMap<FName, uint32> AlreadyFound;
		uint32* Result = AlreadyFound.Find(Name);

		if (!Result)
		{
			const IShaderFormat* SF = FindShaderFormat(Name);

			if (SF)
			{
				Result = &AlreadyFound.Add(Name, SF->GetVersion(Name));
			}
		}

		check(Result);

		return *Result;
	}

	virtual const TArray<const IPhysXCooking*>& GetPhysXCooking() override
	{
		static bool bInitialized = false;
		static TArray<const IPhysXCooking*> Results;

#if WITH_PHYSX
		if (!bInitialized || bForceCacheUpdate)
		{
			bInitialized = true;
			Results.Empty(Results.Num());
			
			TArray<FName> Modules;
			FModuleManager::Get().FindModules(TEXT("PhysXCooking*"), Modules);
			
			if (!Modules.Num())
			{
				UE_LOG(LogTargetPlatformManager, Error, TEXT("No target PhysX formats found!"));
			}

			for (int32 Index = 0; Index < Modules.Num(); Index++)
			{
				IPhysXCookingModule* Module = FModuleManager::LoadModulePtr<IPhysXCookingModule>(Modules[Index]);
				if (Module)
				{
					IPhysXCooking* Format = Module->GetPhysXCooking();
					if (Format != nullptr)
					{
						Results.Add(Format);
					}
				}
			}
		}
#endif // WITH_PHYSX

		return Results;
	}

	virtual const IPhysXCooking* FindPhysXCooking(FName Name) override
	{
#if WITH_PHYSX
		const TArray<const IPhysXCooking*>& PhysXCooking = GetPhysXCooking();

		for (int32 Index = 0; Index < PhysXCooking.Num(); Index++)
		{
			TArray<FName> Formats;

			PhysXCooking[Index]->GetSupportedFormats(Formats);
		
			for (int32 FormatIndex = 0; FormatIndex < Formats.Num(); FormatIndex++)
			{
				if (Formats[FormatIndex] == Name)
				{
					return PhysXCooking[Index];
				}
			}
		}
#endif // WITH_PHYSX

		return nullptr;
	}

protected:

	/**
	 * Checks whether the AutoDesk software development kit (SDK) is enabled.
	 *
	 * @return true if the SDK is enabled, false otherwise.
	 */
	bool IsAutoSDKsEnabled()
	{
		static const FString SDKRootEnvFar(TEXT("UE_SDKS_ROOT"));
		const int32 MaxPathSize = 16384;
		TCHAR SDKPath[MaxPathSize] = { 0 };
		FPlatformMisc::GetEnvironmentVariable(*SDKRootEnvFar, SDKPath, MaxPathSize);

		// AutoSDKs only enabled if UE_SDKS_ROOT is set.
		if (SDKPath[0] != 0)
		{
			return true;
		}
		return false;
	}

	/** Discovers the available target platforms. */
	void DiscoverAvailablePlatforms()
	{
		DECLARE_SCOPE_CYCLE_COUNTER( TEXT( "FTargetPlatformManagerModule::DiscoverAvailablePlatforms" ), STAT_FTargetPlatformManagerModule_DiscoverAvailablePlatforms, STATGROUP_TargetPlatform );

		Platforms.Empty(Platforms.Num());

		TArray<FName> Modules;

		FString ModuleWildCard = TEXT("*TargetPlatform");

#if WITH_EDITOR
		// if we have the editor and we are using -game
		// only need to instantiate the current platform 
#if PLATFORM_WINDOWS
		if (IsRunningGame())
		{
			ModuleWildCard = TEXT("Windows*TargetPlatform");
		}
#endif
#endif
		FModuleManager::Get().FindModules(*ModuleWildCard, Modules);

		// remove this module from the list
		Modules.Remove(FName(TEXT("TargetPlatform")));

		if (!Modules.Num())
		{
			UE_LOG(LogTargetPlatformManager, Error, TEXT("No target platforms found!"));
		}

		FScopedSlowTask SlowTask(Modules.Num());
		for (int32 Index = 0; Index < Modules.Num(); Index++)
		{
			SlowTask.EnterProgressFrame(1);
			ITargetPlatformModule* Module = FModuleManager::LoadModulePtr<ITargetPlatformModule>(Modules[Index]);
			if (Module)
			{
				ITargetPlatform* Platform = Module->GetTargetPlatform();
				if (Platform != nullptr)
				{
					// would like to move this check to GetActiveTargetPlatforms, but too many things cache this result
					// this setup will become faster after TTP 341897 is complete.
RETRY_SETUPANDVALIDATE:
					if (SetupAndValidateAutoSDK(Platform->GetPlatformInfo().AutoSDKPath))
					{
						UE_LOG(LogTemp, Display, TEXT("Loaded TP %s"), *Modules[Index].ToString());
						Platforms.Add(Platform);
					}
					else
					{
						// this hack is here because if you try and setup and validate autosdk some times it will fail because shared files are in use by another child cooker
						static bool bIsChildCooker = FParse::Param(FCommandLine::Get(), TEXT("cookchild"));
						if (bIsChildCooker)
						{
							static int Counter = 0;
							++Counter;
							if (Counter < 10)
							{
								goto RETRY_SETUPANDVALIDATE;
							}
						}
						UE_LOG(LogTemp, Display, TEXT("Failed to SetupAndValidateAutoSDK for platform %s"), *Modules[Index].ToString());
					}
				}
				else
				{
					UE_LOG(LogTemp, Display, TEXT("Failed to get target platform %s"), *Modules[Index].ToString());
				}
			}
		}
	}

	bool UpdatePlatformEnvironment(FString PlatformName, TArray<FString> &Keys, TArray<FString> &Values) override
	{
		SetupEnvironmentVariables(Keys, Values);
		return SetupSDKStatus(PlatformName);	
	}

	bool SetupAndValidateAutoSDK(const FString& AutoSDKPath)
	{
#if AUTOSDKS_ENABLED
		bool bValidSDK = false;
		if (AutoSDKPath.Len() > 0)
		{		
			FName PlatformFName(*AutoSDKPath);

			// cache result of the last setup attempt to avoid calling UBT all the time.
			bool* bPreviousSetupSuccessful = PlatformsSetup.Find(PlatformFName);
			if (bPreviousSetupSuccessful)
			{
				bValidSDK = *bPreviousSetupSuccessful;
			}
			else
			{
				bValidSDK = SetupEnvironmentFromAutoSDK(AutoSDKPath);
				PlatformsSetup.Add(PlatformFName, bValidSDK);
			}
		}
		else
		{
			// if a platform has no AutoSDKPath, then just assume the SDK is installed, we have no basis for determining it.
			bValidSDK = true;
		}
		return bValidSDK;
#else
		return true;
#endif // AUTOSDKS_ENABLED
	}
	
	bool SetupEnvironmentFromAutoSDK(const FString& AutoSDKPath)
	{						
#if AUTOSDKS_ENABLED
		
		if (!IsAutoSDKsEnabled())
		{
			return true;
		}

		// Invoke UBT to perform SDK switching, or detect that a proper manual SDK is already setup.				
#if PLATFORM_WINDOWS
		FString HostPlatform(TEXT("HostWin64"));
#else
#error Fill in your host platform directory
#endif		

		static const FString SDKRootEnvFar(TEXT("UE_SDKS_ROOT"));
		const int32 MaxPathSize = 16384;
		FString SDKPath = FString::ChrN(16384, TEXT('\0'));
		FPlatformMisc::GetEnvironmentVariable(*SDKRootEnvFar, SDKPath.GetCharArray().GetData(), MaxPathSize);

		FString TargetSDKRoot = FPaths::Combine(*SDKPath, *HostPlatform, *AutoSDKPath);
		static const FString SDKInstallManifestFileName(TEXT("CurrentlyInstalled.txt"));
		FString SDKInstallManifestFilePath = FPaths::Combine(*TargetSDKRoot, *SDKInstallManifestFileName);

		// If we are using a manual install, then it is valid for there to be no OutputEnvVars file.
		TUniquePtr<FArchive> InstallManifestFile(IFileManager::Get().CreateFileReader(*SDKInstallManifestFilePath));
		if (InstallManifestFile)
		{
			TArray<FString> FileLines;
			int64 FileSize = InstallManifestFile->TotalSize();
			int64 MemSize = FileSize + 1;
			void* FileMem = FMemory::Malloc(MemSize);
			FMemory::Memset(FileMem, 0, MemSize);

			InstallManifestFile->Serialize(FileMem, FileSize);

			FString FileAsString(ANSI_TO_TCHAR(FileMem));
			FileAsString.ParseIntoArrayLines(FileLines);

			FMemory::Free(FileMem);
			InstallManifestFile->Close();

			
			if (FileLines.Num() != 2)
			{
				UE_LOG(LogTargetPlatformManager, Warning, TEXT("Malformed install manifest file for Platform %s"), *AutoSDKPath);
				return false;
			}

			static const FString ManualSDKString(TEXT("ManualSDK"));
			if (FileLines[1].Compare(ManualSDKString, ESearchCase::IgnoreCase) == 0)
			{
				UE_LOG(LogTargetPlatformManager, Verbose, TEXT("Platform %s has manual sdk install"), *AutoSDKPath);				
				return true;
			}
		}
		else
		{	
			UE_LOG(LogTargetPlatformManager, Log, TEXT("Install manifest file for Platform %s not found.  Platform not set up."), *AutoSDKPath);			
			return false;			
		}		

		static const FString SDKEnvironmentVarsFile(TEXT("OutputEnvVars.txt"));
		FString EnvVarFileName = FPaths::Combine(*TargetSDKRoot, *SDKEnvironmentVarsFile);		

		// If we are using a manual install, then it is valid for there to be no OutputEnvVars file.
		TUniquePtr<FArchive> EnvVarFile(IFileManager::Get().CreateFileReader(*EnvVarFileName));
		if (EnvVarFile)
		{
			TArray<FString> FileLines;
			{
				int64 FileSize = EnvVarFile->TotalSize();
				int64 MemSize = FileSize + 1;
				void* FileMem = FMemory::Malloc(MemSize);
				FMemory::Memset(FileMem, 0, MemSize);

				EnvVarFile->Serialize(FileMem, FileSize);

				FString FileAsString(ANSI_TO_TCHAR(FileMem));
				FileAsString.ParseIntoArrayLines(FileLines);

				FMemory::Free(FileMem);
				EnvVarFile->Close();
			}

			TArray<FString> PathAdds;
			TArray<FString> PathRemoves;
			TArray<FString> EnvVarNames;
			TArray<FString> EnvVarValues;

			const FString VariableSplit(TEXT("="));
			for (int32 i = 0; i < FileLines.Num(); ++i)
			{				
				const FString& VariableString = FileLines[i];

				FString Left;
				FString Right;
				VariableString.Split(VariableSplit, &Left, &Right);
				
				if (Left.Compare(TEXT("strippath"), ESearchCase::IgnoreCase) == 0)
				{
					PathRemoves.Add(Right);
				}
				else if (Left.Compare(TEXT("addpath"), ESearchCase::IgnoreCase) == 0)
				{
					PathAdds.Add(Right);
				}
				else
				{
					// convenience for setup.bat writers.  Trim any accidental whitespace from var names/values.
					EnvVarNames.Add(Left.TrimStartAndEnd());
					EnvVarValues.Add(Right.TrimStartAndEnd());
				}
			}

			// don't actually set anything until we successfully validate and read all values in.
			// we don't want to set a few vars, return a failure, and then have a platform try to
			// build against a manually installed SDK with half-set env vars.
			SetupEnvironmentVariables(EnvVarNames, EnvVarValues);


			const int32 MaxPathVarLen = 32768;
			FString OrigPathVar = FString::ChrN(MaxPathVarLen, TEXT('\0'));
			FPlatformMisc::GetEnvironmentVariable(TEXT("PATH"), OrigPathVar.GetCharArray().GetData(), MaxPathVarLen);

			// actually perform the PATH stripping / adding.
			const TCHAR* PathDelimiter = FPlatformMisc::GetPathVarDelimiter();
			TArray<FString> PathVars;
			OrigPathVar.ParseIntoArray(PathVars, PathDelimiter, true);

			TArray<FString> ModifiedPathVars;
			ModifiedPathVars = PathVars;

			// perform removes first, in case they overlap with any adds.
			for (int32 PathRemoveIndex = 0; PathRemoveIndex < PathRemoves.Num(); ++PathRemoveIndex)
			{
				const FString& PathRemove = PathRemoves[PathRemoveIndex];
				for (int32 PathVarIndex = 0; PathVarIndex < PathVars.Num(); ++PathVarIndex)
				{
					const FString& PathVar = PathVars[PathVarIndex];
					if (PathVar.Find(PathRemove, ESearchCase::IgnoreCase) >= 0)
					{
						UE_LOG(LogTargetPlatformManager, Verbose, TEXT("Removing Path: '%s'"), *PathVar);
						ModifiedPathVars.Remove(PathVar);
					}
				}
			}

			// remove all the of ADDs so that if this function is executed multiple times, the paths will be guarateed to be in the same order after each run.
			// If we did not do this, a 'remove' that matched some, but not all, of our 'adds' would cause the order to change.
			for (int32 PathAddIndex = 0; PathAddIndex < PathAdds.Num(); ++PathAddIndex)			
			{
				const FString& PathAdd = PathAdds[PathAddIndex];				
				for (int32 PathVarIndex = 0; PathVarIndex < PathVars.Num(); ++PathVarIndex)
				{
					const FString& PathVar = PathVars[PathVarIndex];
					if (PathVar.Find(PathAdd, ESearchCase::IgnoreCase) >= 0)
					{
						UE_LOG(LogTargetPlatformManager, Verbose, TEXT("Removing Path: '%s'"), *PathVar);
						ModifiedPathVars.Remove(PathVar);
					}
				}
			}

			// perform adds, but don't add duplicates
			for (int32 PathAddIndex = 0; PathAddIndex < PathAdds.Num(); ++PathAddIndex)
			{
				const FString& PathAdd = PathAdds[PathAddIndex];
				if (!ModifiedPathVars.Contains(PathAdd))
				{
					UE_LOG(LogTargetPlatformManager, Verbose, TEXT("Adding Path: '%s'"), *PathAdd);					
					ModifiedPathVars.Add(PathAdd);
				}
			}

			FString ModifiedPath = FString::Join(ModifiedPathVars, PathDelimiter);
			FPlatformMisc::SetEnvironmentVar(TEXT("PATH"), *ModifiedPath);			
		}
		else
		{
			UE_LOG(LogTargetPlatformManager, Warning, TEXT("OutputEnvVars.txt not found for platform: '%s'"), *AutoSDKPath);			
			return false;
		}

		UE_LOG(LogTargetPlatformManager, Verbose, TEXT("Platform %s has auto sdk install"), *AutoSDKPath);		
		return true;
#else
		return true;
#endif
	}

	bool SetupSDKStatus()
	{
		return SetupSDKStatus(TEXT(""));
	}

	bool SetupSDKStatus(FString TargetPlatforms)
	{
		DECLARE_SCOPE_CYCLE_COUNTER( TEXT( "FTargetPlatformManagerModule::SetupSDKStatus" ), STAT_FTargetPlatformManagerModule_SetupSDKStatus, STATGROUP_TargetPlatform );

		// run UBT with -validate -allplatforms and read the output
		FString CmdExe, CommandLine;
		
		if (PLATFORM_MAC)
		{
			CmdExe = TEXT("/bin/sh");
			FString ScriptPath = FPaths::ConvertRelativePathToFull(FPaths::EngineDir() / TEXT("Build/BatchFiles/Mac/RunMono.sh"));
			CommandLine = TEXT("\"") + ScriptPath + TEXT("\" \"") + FPaths::ConvertRelativePathToFull(FPaths::EngineDir() / TEXT("Binaries/DotNET/UnrealBuildTool.exe")) + TEXT("\" -validateplatform");
		}
		else if (PLATFORM_WINDOWS)
		{
			CmdExe = FPaths::ConvertRelativePathToFull(FPaths::EngineDir() / TEXT("Binaries/DotNET/UnrealBuildTool.exe"));
			CommandLine = TEXT("-validateplatform");
		}
		else if (PLATFORM_LINUX)
		{
			CmdExe = TEXT("/bin/bash");	// bash and not sh because of pushd
			FString ScriptPath = FPaths::ConvertRelativePathToFull(FPaths::EngineDir() / TEXT("Build/BatchFiles/Linux/RunMono.sh"));
			CommandLine = TEXT("\"") + ScriptPath + TEXT("\" \"") + FPaths::ConvertRelativePathToFull(FPaths::EngineDir() / TEXT("Binaries/DotNET/UnrealBuildTool.exe")) + TEXT("\" -validateplatform");
		}
		else
		{
			checkf(false, TEXT("FTargetPlatformManagerModule::SetupSDKStatus(): Unsupported platform!"));
		}

		// Allow for only a subset of platforms to be reparsed - needed when kicking a change from the UI
		CommandLine += TargetPlatforms.IsEmpty() ? TEXT(" -allplatforms") : (TEXT(" -platforms=") + TargetPlatforms);

		TSharedPtr<FMonitoredProcess> UBTProcess = MakeShareable(new FMonitoredProcess(CmdExe, CommandLine, true));
		UBTProcess->OnOutput().BindStatic(&FTargetPlatformManagerModule::OnStatusOutput);
		SDKStatusMessage = TEXT("");
		UBTProcess->Launch();
		while(UBTProcess->Update())
		{
			FPlatformProcess::Sleep(0.01f);
		}

		TArray<FString> PlatArray;
		SDKStatusMessage.ParseIntoArrayWS(PlatArray);
		for (int Index = 0; Index < PlatArray.Num()-2; ++Index)
		{
			FString Item = PlatArray[Index];
			if (PlatArray[Index].Contains(TEXT("##PlatformValidate:")))
			{
				PlatformInfo::EPlatformSDKStatus Status = PlatArray[Index+2].Contains(TEXT("INVALID")) ? PlatformInfo::EPlatformSDKStatus::NotInstalled : PlatformInfo::EPlatformSDKStatus::Installed;
				FString PlatformName = PlatArray[Index+1];
				if (PlatformName == TEXT("Win32") || PlatformName == TEXT("Win64"))
				{
					PlatformName = TEXT("Windows");
					PlatformInfo::UpdatePlatformSDKStatus(PlatformName, Status);
					PlatformName = TEXT("WindowsNoEditor");
					PlatformInfo::UpdatePlatformSDKStatus(PlatformName, Status);
					PlatformName = TEXT("WindowsClient");
					PlatformInfo::UpdatePlatformSDKStatus(PlatformName, Status);
					PlatformName = TEXT("WindowsServer");
					PlatformInfo::UpdatePlatformSDKStatus(PlatformName, Status);
				}
				else if (PlatformName == TEXT("Mac"))
				{
					PlatformInfo::UpdatePlatformSDKStatus(PlatformName, Status);
					PlatformName = TEXT("MacNoEditor");
					PlatformInfo::UpdatePlatformSDKStatus(PlatformName, Status);
					PlatformName = TEXT("MacClient");
					PlatformInfo::UpdatePlatformSDKStatus(PlatformName, Status);
					PlatformName = TEXT("MacServer");
					PlatformInfo::UpdatePlatformSDKStatus(PlatformName, Status);
				}
				else if (PlatformName == TEXT("Linux"))
				{
					PlatformInfo::UpdatePlatformSDKStatus(PlatformName, Status);
					PlatformName = TEXT("LinuxNoEditor");
					PlatformInfo::UpdatePlatformSDKStatus(PlatformName, Status);
					PlatformName = TEXT("LinuxClient");
					PlatformInfo::UpdatePlatformSDKStatus(PlatformName, Status);
					PlatformName = TEXT("LinuxServer");
					PlatformInfo::UpdatePlatformSDKStatus(PlatformName, Status);
				}
				else if (PlatformName == TEXT("Desktop"))
				{
					// since Desktop is just packaging, we don't need an SDK, and UBT will return INVALID, since it doesn't build for it
					PlatformInfo::UpdatePlatformSDKStatus(PlatformName, PlatformInfo::EPlatformSDKStatus::Installed);
				}
				else
				{
					PlatformInfo::UpdatePlatformSDKStatus(PlatformName, Status);
				}
			}
		}
		return true;
	}

private:

	void SetupEnvironmentVariables(TArray<FString> &EnvVarNames, const TArray<FString>& EnvVarValues)
	{
		for (int i = 0; i < EnvVarNames.Num(); ++i)
		{
			const FString& EnvVarName = EnvVarNames[i];
			const FString& EnvVarValue = EnvVarValues[i];
			UE_LOG(LogTargetPlatformManager, Verbose, TEXT("Setting variable '%s' to '%s'."), *EnvVarName, *EnvVarValue);
			FPlatformMisc::SetEnvironmentVar(*EnvVarName, *EnvVarValue);
		}
	}

	void ModulesChangesCallback(FName ModuleName, EModuleChangeReason ReasonForChange)
	{
		if (!bIgnoreFirstDelegateCall && ModuleName.ToString().Contains(TEXT("TargetPlatform")) && !ModuleName.ToString().Contains(TEXT("ProjectTargetPlatformEditor")))
		{
			Invalidate();
		}
		bIgnoreFirstDelegateCall = false;
	}
	
	static FString SDKStatusMessage;
	static void OnStatusOutput(FString Message)
	{
		SDKStatusMessage += Message;
	}

	// If true we should build formats that are actually required for use by the runtime. 
	// This happens for an ordinary editor run and more specifically whenever there is no
	// TargetPlatform= on the command line.
	bool bRestrictFormatsToRuntimeOnly;

	// Flag to force reinitialization of all cached data. This is needed to have up-to-date caches
	// in case of a module reload of a TargetPlatform-Module.
	bool bForceCacheUpdate;

	// Flag to avoid redunant reloads
	bool bIgnoreFirstDelegateCall;

	// Holds the list of discovered platforms.
	TArray<ITargetPlatform*> Platforms;

#if AUTOSDKS_ENABLED
	// holds the list of Platforms that have attempted setup.
	TMap<FName, bool> PlatformsSetup;
#endif
};


FString FTargetPlatformManagerModule::SDKStatusMessage = TEXT("");


IMPLEMENT_MODULE(FTargetPlatformManagerModule, TargetPlatform);