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

239 lines
7.9 KiB
C++

// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once
#include "Containers/ContainersFwd.h"
#include "DerivedDataCacheKey.h"
#include "DerivedDataValueId.h"
#include "HAL/Platform.h"
#include "Memory/MemoryFwd.h"
#include "Misc/ScopeExit.h"
#include "Templates/Function.h"
#include "Templates/RefCounting.h"
#include "Templates/UniquePtr.h"
#include "Templates/UnrealTemplate.h"
#define UE_API DERIVEDDATACACHE_API
class FCbObject;
class FCbPackage;
class FCbWriter;
namespace UE::DerivedData { class FCacheRecord; }
namespace UE::DerivedData { class FOptionalCacheRecord; }
namespace UE::DerivedData { class FValue; }
namespace UE::DerivedData { class FValueWithId; }
namespace UE::DerivedData { class IRequestOwner; }
namespace UE::DerivedData { using FOnCacheRecordComplete = TUniqueFunction<void (FCacheRecord&& Record)>; }
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
namespace UE::DerivedData::Private
{
class ICacheRecordInternal
{
public:
virtual ~ICacheRecordInternal() = default;
virtual const FCacheKey& GetKey() const = 0;
virtual const FCbObject& GetMeta() const = 0;
virtual const FValueWithId& GetValue(const FValueId& Id) const = 0;
virtual TConstArrayView<FValueWithId> GetValues() const = 0;
virtual void AddRef() const = 0;
virtual void Release() const = 0;
};
FCacheRecord CreateCacheRecord(ICacheRecordInternal* Record);
class ICacheRecordBuilderInternal
{
public:
virtual ~ICacheRecordBuilderInternal() = default;
virtual void SetMeta(FCbObject&& Meta) = 0;
virtual void AddValue(const FValueId& Id, const FValue& Value) = 0;
virtual FCacheRecord Build() = 0;
virtual void BuildAsync(IRequestOwner& Owner, FOnCacheRecordComplete&& OnComplete) = 0;
};
} // UE::DerivedData::Private
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
namespace UE::DerivedData
{
/**
* A cache record is a key, an array of values, and metadata.
*
* The key must uniquely correspond to its values. The key must never be reused for other values.
* The metadata does not have this requirement and may be used to persist details that vary, such
* as the time to generate the values or the machine that generated them.
*/
class FCacheRecord
{
public:
/** Returns the key that identifies this record in the cache. */
inline const FCacheKey& GetKey() const { return Record->GetKey(); }
/** Returns the metadata. Null when requested with ECachePolicy::SkipMeta. */
inline const FCbObject& GetMeta() const { return Record->GetMeta(); }
/** Returns the value matching the ID. Null if no match. Data is null if skipped. */
inline const FValueWithId& GetValue(const FValueId& Id) const { return Record->GetValue(Id); }
/** Returns a view of the values ordered by ID. Data is null if skipped. */
inline TConstArrayView<FValueWithId> GetValues() const { return Record->GetValues(); }
/** Save the cache record to a compact binary package. */
UE_API FCbPackage Save() const;
/** Append the cache record to an existing package and writer for e.g. a batch of records. */
UE_API void Save(FCbPackage& Attachments, FCbWriter& Writer) const;
/** Load a cache record from a compact binary package. Null on error. */
UE_API static FOptionalCacheRecord Load(const FCbPackage& Package);
UE_API static FOptionalCacheRecord Load(const FCbPackage& Attachments, const FCbObject& Object);
private:
friend class FOptionalCacheRecord;
friend FCacheRecord Private::CreateCacheRecord(Private::ICacheRecordInternal* Record);
/** Construct a cache record. Use Build() or BuildAsync() on FCacheRecordBuilder. */
inline explicit FCacheRecord(Private::ICacheRecordInternal* InRecord)
: Record(InRecord)
{
}
TRefCountPtr<Private::ICacheRecordInternal> Record;
};
/**
* A cache record builder is used to construct a cache record.
*
* Create using a key that uniquely corresponds to the values for the cache record.
* The metadata may vary between records with the same key.
*
* @see FCacheRecord
*/
class FCacheRecordBuilder
{
public:
/**
* Create a cache record builder from a cache key.
*/
UE_API explicit FCacheRecordBuilder(const FCacheKey& Key);
/**
* Set the metadata for the cache record.
*
* @param Meta The metadata, which is cloned if not owned.
*/
inline void SetMeta(FCbObject&& Meta)
{
return RecordBuilder->SetMeta(MoveTemp(Meta));
}
/**
* Add a value to the cache record.
*
* @param Id An ID for the value that is unique within this cache record.
* @param Buffer The value, which is compressed by the builder, and cloned if not owned.
* @param BlockSize The power-of-two block size to encode raw data in. 0 is default.
*/
UE_API void AddValue(const FValueId& Id, const FCompositeBuffer& Buffer, uint64 BlockSize = 0);
UE_API void AddValue(const FValueId& Id, const FSharedBuffer& Buffer, uint64 BlockSize = 0);
/**
* Add a value to the cache record.
*
* @note The ID for the value must be unique within this cache record.
*/
UE_API void AddValue(const FValueWithId& Value);
/**
* Add a value to the cache record.
*
* @param Id An ID for the value that is unique within this cache record.
*/
inline void AddValue(const FValueId& Id, const FValue& Value)
{
return RecordBuilder->AddValue(Id, Value);
}
/**
* Build a cache record, which makes this builder subsequently unusable.
*
* Prefer BuildAsync() when the values are added from raw buffers, which requires compressing
* those buffers before constructing the cache record.
*/
inline FCacheRecord Build()
{
ON_SCOPE_EXIT { RecordBuilder = nullptr; };
return RecordBuilder->Build();
}
/**
* Build a cache record asynchronously, which makes this builder subsequently unusable.
*
* Prefer Build() when the values are added from compressed buffers as compression is already
* complete and BuildAsync() will complete immediately in that case.
*/
inline void BuildAsync(IRequestOwner& Owner, FOnCacheRecordComplete&& OnComplete)
{
return RecordBuilder.Release()->BuildAsync(Owner, MoveTemp(OnComplete));
}
private:
TUniquePtr<Private::ICacheRecordBuilderInternal> RecordBuilder;
};
/**
* A cache record that can be null.
*
* @see FCacheRecord
*/
class FOptionalCacheRecord : private FCacheRecord
{
public:
inline FOptionalCacheRecord() : FCacheRecord(nullptr) {}
inline FOptionalCacheRecord(FCacheRecord&& InRecord) : FCacheRecord(MoveTemp(InRecord)) {}
inline FOptionalCacheRecord(const FCacheRecord& InRecord) : FCacheRecord(InRecord) {}
inline FOptionalCacheRecord& operator=(FCacheRecord&& InRecord) { FCacheRecord::operator=(MoveTemp(InRecord)); return *this; }
inline FOptionalCacheRecord& operator=(const FCacheRecord& InRecord) { FCacheRecord::operator=(InRecord); return *this; }
/** Returns the cache record. The caller must check for null before using this accessor. */
inline const FCacheRecord& Get() const & { return *this; }
inline FCacheRecord Get() && { return MoveTemp(*this); }
inline bool IsNull() const { return !IsValid(); }
inline bool IsValid() const { return Record.IsValid(); }
inline explicit operator bool() const { return IsValid(); }
inline void Reset() { *this = FOptionalCacheRecord(); }
};
} // UE::DerivedData
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
namespace UE::DerivedData
{
/** An implementation of KeyFuncs to compare FCacheRecord by its FCacheKey. */
struct FCacheRecordKeyFuncs
{
using KeyType = FCacheKey;
using KeyInitType = const FCacheKey&;
using ElementInitType = const FCacheRecord&;
static constexpr bool bAllowDuplicateKeys = false;
static inline KeyInitType GetSetKey(ElementInitType Record) { return Record.GetKey(); }
static inline uint32 GetKeyHash(KeyInitType Key) { return GetTypeHash(Key); }
static inline bool Matches(KeyInitType A, KeyInitType B) { return A == B; }
};
} // UE::DerivedData
#undef UE_API