Files
UnrealEngine/Engine/Source/Developer/DerivedDataCache/Public/DerivedDataCacheKey.h
2025-05-18 13:04:45 +08:00

169 lines
5.3 KiB
C++

// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once
#include "Containers/StringFwd.h"
#include "Containers/StringView.h"
#include "CoreTypes.h"
#include "IO/IoHash.h"
#include "Misc/AsciiSet.h"
#include "Misc/CString.h"
#include "Templates/TypeHash.h"
#define UE_API DERIVEDDATACACHE_API
class FCbFieldView;
class FCbWriter;
namespace UE::DerivedData
{
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
* An alphanumeric identifier that groups related cache records.
*
* A cache bucket name must be alphanumeric, non-empty, and contain fewer than 64 code units.
*/
class FCacheBucket
{
public:
/** Maximum number of code units in a valid cache bucket name. */
static constexpr int32 MaxNameLen = 63;
/** Returns true if the name is a valid cache bucket name. */
template <typename CharType>
static inline bool IsValidName(TStringView<CharType> Name)
{
constexpr FAsciiSet Valid("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789");
return !Name.IsEmpty() && Name.Len() <= MaxNameLen && FAsciiSet::HasOnly(Name, Valid);
}
/** Construct a null cache bucket. */
FCacheBucket() = default;
/** Create a cache bucket from a name. */
UE_API explicit FCacheBucket(FUtf8StringView Name);
UE_API explicit FCacheBucket(FWideStringView Name);
/** Create a cache bucket from a name and a display name. */
UE_API FCacheBucket(FUtf8StringView Name, FStringView DisplayName);
UE_API FCacheBucket(FWideStringView Name, FStringView DisplayName);
/** Append the display name if available or the bucket name if not. */
UE_API void ToDisplayName(FStringBuilderBase& OutDisplayName) const;
/** Whether this is null. */
inline bool IsNull() const { return !Name; }
/** Whether this is not null. */
inline bool IsValid() const { return !IsNull(); }
/** Reset this to null. */
inline void Reset() { *this = FCacheBucket(); }
inline bool operator==(FCacheBucket Other) const { return Name == Other.Name; }
inline bool operator!=(FCacheBucket Other) const { return Name != Other.Name; }
inline bool operator<(FCacheBucket Other) const
{
return Name != Other.Name && ToString().Compare(Other.ToString(), ESearchCase::IgnoreCase) < 0;
}
friend inline uint32 GetTypeHash(FCacheBucket Bucket)
{
return ::GetTypeHash(reinterpret_cast<UPTRINT>(Bucket.Name));
}
/** Get the name of the cache bucket as a string. */
inline FAnsiStringView ToString() const;
/** Get the name of the cache bucket as a null-terminated string. */
inline const ANSICHAR* ToCString() const { return Name; }
protected:
static constexpr int32 LengthOffset = -1;
/** Name stored as a null-terminated string preceded by one byte containing its length. */
const ANSICHAR* Name = nullptr;
};
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/** A key that uniquely identifies a cache record. */
struct FCacheKey
{
FCacheBucket Bucket;
FIoHash Hash;
/** A key with a null bucket and a zero hash. */
static const FCacheKey Empty;
friend inline bool operator==(const FCacheKey& A, const FCacheKey& B)
{
return A.Bucket == B.Bucket && A.Hash == B.Hash;
}
friend inline bool operator!=(const FCacheKey& A, const FCacheKey& B)
{
return A.Bucket != B.Bucket || A.Hash != B.Hash;
}
friend inline bool operator<(const FCacheKey& A, const FCacheKey& B)
{
const FCacheBucket& BucketA = A.Bucket;
const FCacheBucket& BucketB = B.Bucket;
return BucketA == BucketB ? A.Hash < B.Hash : BucketA < BucketB;
}
friend inline uint32 GetTypeHash(const FCacheKey& Key)
{
return HashCombine(GetTypeHash(Key.Bucket), GetTypeHash(Key.Hash));
}
};
inline const FCacheKey FCacheKey::Empty;
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
inline FAnsiStringView FCacheBucket::ToString() const
{
return Name ? FAnsiStringView(Name, reinterpret_cast<const uint8*>(Name)[LengthOffset]) : FAnsiStringView();
}
template <typename CharType>
inline TStringBuilderBase<CharType>& operator<<(TStringBuilderBase<CharType>& Builder, const FCacheBucket& Bucket)
{
return Builder << Bucket.ToString();
}
UE_API FCbWriter& operator<<(FCbWriter& Writer, FCacheBucket Bucket);
UE_API bool LoadFromCompactBinary(FCbFieldView Field, FCacheBucket& OutBucket);
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
template <typename CharType>
inline TStringBuilderBase<CharType>& operator<<(TStringBuilderBase<CharType>& Builder, const FCacheKey& Key)
{
return Builder << Key.Bucket << CharType('/') << Key.Hash;
}
UE_API void SerializeForLog(FCbWriter& Writer, const FCacheKey& Key);
UE_API FCbWriter& operator<<(FCbWriter& Writer, const FCacheKey& Key);
UE_API bool LoadFromCompactBinary(FCbFieldView Field, FCacheKey& OutKey);
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
* Constructs a cache key from a legacy cache key.
*
* Legacy keys are typically of the form DATATYPENAME_VersionGuid_TypeSpecificSuffix.
*/
UE_API FCacheKey ConvertLegacyCacheKey(FStringView Key);
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
} // UE::DerivedData
#undef UE_API