WorldPartitionCookPackage.h

Go to the documentation of this file.

// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once
 
#if WITH_EDITOR
#include "CoreMinimal.h"
#include "Hash/CityHash.h"
#include "Misc/Paths.h"
#include "WorldPartition/WorldPartitionLog.h"
#include "UObject/Package.h"
#include "Hash/Blake3.h"
 
using FWorldPartitionPackageHash = FBlake3Hash;
using FWorldPartitionPackageHashBuilder = FBlake3;
 
#else
#include "Containers/StringView.h"
#endif
 
struct FWorldPartitionCookPackage
{
#if WITH_EDITOR
 
    enum class EType
    {
        Unknown,
        Level,
        Generic
    };
 
    using IDType = uint64;
 
    static IDType MakeCookPackageID(const FString& InRoot, const FString& InRelativeFilename)
    {
        check(!InRoot.IsEmpty() && !InRelativeFilename.IsEmpty());
        check(InRoot[0] == '/' && InRoot[InRoot.Len() - 1] != '/'); // Root is assumed to be in the format "/Root"
        check(InRelativeFilename[0] == '/' && InRelativeFilename[InRelativeFilename.Len() - 1] != '/'); // RelativeFileName is assumed to be in the format "/Relativefilename
 
        // Avoid doing string copies as this function is often called during cook when bridging between Cook code & WorldPartition code.
        // Compute a hash for both InRoot & InRelativeFilename. Then combine them instead of creating a new fullpath string and computing the hash on it.
        uint64 RootHash = CityHash64(reinterpret_cast<const char*>(*InRoot), InRoot.Len() * sizeof(TCHAR));
        uint64 RelativePathHash = CityHash64(reinterpret_cast<const char*>(*InRelativeFilename), InRelativeFilename.Len() * sizeof(TCHAR));
        return RootHash ^ RelativePathHash;
    }
 
    // PathComponents (Root & RelativePath members) need to follow the "/<PathComponent>" format for the PackageId computation to work.
    static FString SanitizePathComponent(const FString& Path)
    {
        FString SanitizedPath = TEXT("/") + Path;
        FPaths::RemoveDuplicateSlashes(SanitizedPath);
 
        if (SanitizedPath[SanitizedPath.Len() - 1] == '/')
        {
            SanitizedPath.RemoveAt(SanitizedPath.Len() - 1, 1);
        }
 
        return SanitizedPath;
    }
 
    static FString MakeGeneratedFullPath(const FString& InRoot, const FString& InRelativeFilename)
    {
        TStringBuilderWithBuffer<TCHAR, NAME_SIZE> FullPath;
        FullPath += TEXT("/");
        FullPath += InRoot;
        FullPath += GeneratedFolder;
        FullPath += InRelativeFilename;
 
        return FPaths::RemoveDuplicateSlashes(*FullPath);
    }
 
    FWorldPartitionCookPackage(const FString& InRoot, const FString& InRelativePath, EType InType, const FWorldPartitionPackageHash& InGenerationHash)
        : Root(SanitizePathComponent(InRoot)),
        RelativePath(SanitizePathComponent(InRelativePath)),
        PackageId(MakeCookPackageID(Root, RelativePath)),
        Type(InType),
        GenerationHash(InGenerationHash)
    {
    }
 
    FString GetFullGeneratedPath() const { return MakeGeneratedFullPath(Root, RelativePath); }
 
    UPackage* GetPackage() const { return FindObject<UPackage>(nullptr, *GetFullGeneratedPath()); }
 
    const FString Root;
    const FString RelativePath;
    const IDType PackageId;
    const EType Type;
    const FWorldPartitionPackageHash GenerationHash;
#endif
 
    static FStringView GetGeneratedFolderName() { return FStringView(&GeneratedFolder[1], GeneratedFolder.Len() - 2); }
 
private:
    static constexpr FStringView GeneratedFolder = TEXTVIEW("/_Generated_/");
};