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// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once
#include <zencore/compactbinary.h>
#include <zencore/iobuffer.h>
#include <zencore/iohash.h>
#include <zencore/thread.h>
#include <zencore/uid.h>
#include <zenstore/basicfile.h>
#include <zenstore/cas.h>
#include <zenstore/caslog.h>
#include <zenstore/gc.h>
ZEN_THIRD_PARTY_INCLUDES_START
#include <tsl/robin_map.h>
ZEN_THIRD_PARTY_INCLUDES_END
#include <compare>
#include <filesystem>
#include <unordered_map>
namespace zen {
class CasStore;
class CasGc;
class WideStringBuilderBase;
class ZenCacheTracker;
/******************************************************************************
/$$$$$$$$ /$$$$$$ /$$
|_____ $$ /$$__ $$ | $$
/$$/ /$$$$$$ /$$$$$$$ | $$ \__/ /$$$$$$ /$$$$$$| $$$$$$$ /$$$$$$
/$$/ /$$__ $| $$__ $$ | $$ |____ $$/$$_____| $$__ $$/$$__ $$
/$$/ | $$$$$$$| $$ \ $$ | $$ /$$$$$$| $$ | $$ \ $| $$$$$$$$
/$$/ | $$_____| $$ | $$ | $$ $$/$$__ $| $$ | $$ | $| $$_____/
/$$$$$$$| $$$$$$| $$ | $$ | $$$$$$| $$$$$$| $$$$$$| $$ | $| $$$$$$$
|________/\_______|__/ |__/ \______/ \_______/\_______|__/ |__/\_______/
Cache store for UE5. Restricts keys to "{bucket}/{hash}" pairs where the hash
is 40 (hex) chars in size. Values may be opaque blobs or structured objects
which can in turn contain references to other objects (or blobs).
******************************************************************************/
struct ZenCacheValue
{
IoBuffer Value;
CbObject IndexData;
};
/** In-memory cache storage
Intended for small values which are frequently accessed
This should have a better memory management policy to maintain reasonable
footprint.
*/
class ZenCacheMemoryLayer
{
public:
ZenCacheMemoryLayer();
~ZenCacheMemoryLayer();
bool Get(std::string_view Bucket, const IoHash& HashKey, ZenCacheValue& OutValue);
void Put(std::string_view Bucket, const IoHash& HashKey, const ZenCacheValue& Value);
bool DropBucket(std::string_view Bucket);
void Scrub(ScrubContext& Ctx);
void GatherReferences(GcContext& GcCtx);
struct Configuration
{
uint64_t TargetFootprintBytes = 16 * 1024 * 1024;
uint64_t ScavengeThreshold = 4 * 1024 * 1024;
};
const Configuration& GetConfiguration() const { return m_Configuration; }
void SetConfiguration(const Configuration& NewConfig) { m_Configuration = NewConfig; }
private:
struct CacheBucket
{
struct BucketValue
{
uint64_t LastAccess = 0;
IoBuffer Payload;
};
RwLock m_bucketLock;
tsl::robin_map<IoHash, BucketValue> m_cacheMap;
bool Get(const IoHash& HashKey, ZenCacheValue& OutValue);
void Put(const IoHash& HashKey, const ZenCacheValue& Value);
void Scrub(ScrubContext& Ctx);
void GatherReferences(GcContext& GcCtx);
private:
uint64_t GetCurrentTimeStamp();
};
RwLock m_Lock;
std::unordered_map<std::string, CacheBucket> m_Buckets;
Configuration m_Configuration;
};
class ZenCacheDiskLayer
{
public:
explicit ZenCacheDiskLayer(const std::filesystem::path& RootDir);
~ZenCacheDiskLayer();
bool Get(std::string_view Bucket, const IoHash& HashKey, ZenCacheValue& OutValue);
void Put(std::string_view Bucket, const IoHash& HashKey, const ZenCacheValue& Value);
bool DropBucket(std::string_view Bucket);
void Flush();
void Scrub(ScrubContext& Ctx);
void GatherReferences(GcContext& GcCtx);
void DiscoverBuckets();
private:
/** A cache bucket manages a single directory containing
metadata and data for that bucket
*/
struct CacheBucket;
std::filesystem::path m_RootDir;
RwLock m_Lock;
std::unordered_map<std::string, CacheBucket> m_Buckets; // TODO: make this case insensitive
};
class ZenCacheStore : public GcContributor
{
public:
ZenCacheStore(CasGc& Gc, const std::filesystem::path& RootDir);
~ZenCacheStore();
bool Get(std::string_view Bucket, const IoHash& HashKey, ZenCacheValue& OutValue);
void Put(std::string_view Bucket, const IoHash& HashKey, const ZenCacheValue& Value);
bool DropBucket(std::string_view Bucket);
void Flush();
void Scrub(ScrubContext& Ctx);
virtual void GatherReferences(GcContext& GcCtx) override;
private:
std::filesystem::path m_RootDir;
ZenCacheMemoryLayer m_MemLayer;
ZenCacheDiskLayer m_DiskLayer;
uint64_t m_DiskLayerSizeThreshold = 1 * 1024;
uint64_t m_LastScrubTime = 0;
std::unique_ptr<ZenCacheTracker> m_AccessTracker;
};
void z$_forcelink();
} // namespace zen
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