Split out structured cache store code into dedicated cpp/h pair

1 files changed, 554 insertions, 0 deletions

diff --git a/zenserver/cache/structuredcachestore.cpp b/zenserver/cache/structuredcachestore.cpp
new file mode 100644
index 000000000..3e0050fab
--- /dev/null
+++ b/zenserver/cache/structuredcachestore.cpp
@@ -0,0 +1,554 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#include "structuredcachestore.h"
+
+#include <zencore/except.h>
+#include <zencore/windows.h>
+
+#include <zencore/filesystem.h>
+#include <zencore/fmtutils.h>
+#include <zencore/iobuffer.h>
+#include <zencore/string.h>
+#include <zencore/thread.h>
+#include <zenstore/basicfile.h>
+#include <zenstore/cas.h>
+#include <zenstore/caslog.h>
+
+#include <fmt/core.h>
+#include <spdlog/spdlog.h>
+#include <concepts>
+#include <filesystem>
+#include <gsl/gsl-lite.hpp>
+#include <unordered_map>
+
+#include <atlfile.h>
+
+using namespace zen;
+using namespace fmt::literals;
+
+//////////////////////////////////////////////////////////////////////////
+
+ZenCacheStore::ZenCacheStore(zen::CasStore& Cas, const std::filesystem::path& RootDir) : m_DiskLayer{Cas, RootDir}
+{
+	zen::CreateDirectories(RootDir);
+}
+
+ZenCacheStore::~ZenCacheStore()
+{
+}
+
+bool
+ZenCacheStore::Get(std::string_view InBucket, const zen::IoHash& HashKey, ZenCacheValue& OutValue)
+{
+	bool Ok = m_MemLayer.Get(InBucket, HashKey, OutValue);
+
+	if (!Ok)
+	{
+		Ok = m_DiskLayer.Get(InBucket, HashKey, OutValue);
+
+#if 0  // This would keep file handles open
+		if (ok)
+		{
+			m_memLayer.Put(InBucket, HashKey, OutValue);
+		}
+#endif
+	}
+
+	return Ok;
+}
+
+void
+ZenCacheStore::Put(std::string_view InBucket, const zen::IoHash& HashKey, const ZenCacheValue& Value)
+{
+	m_MemLayer.Put(InBucket, HashKey, Value);
+	m_DiskLayer.Put(InBucket, HashKey, Value);
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+ZenCacheMemoryLayer::ZenCacheMemoryLayer()
+{
+}
+
+ZenCacheMemoryLayer::~ZenCacheMemoryLayer()
+{
+}
+
+bool
+ZenCacheMemoryLayer::Get(std::string_view InBucket, const zen::IoHash& HashKey, ZenCacheValue& OutValue)
+{
+	CacheBucket* Bucket = nullptr;
+
+	{
+		RwLock::SharedLockScope _(m_Lock);
+
+		auto it = m_Buckets.find(std::string(InBucket));
+
+		if (it != m_Buckets.end())
+		{
+			Bucket = &it->second;
+		}
+	}
+
+	if (Bucket == nullptr)
+		return false;
+
+	ZEN_ASSERT(Bucket != nullptr);
+
+	return Bucket->Get(HashKey, OutValue);
+}
+
+void
+ZenCacheMemoryLayer::Put(std::string_view InBucket, const zen::IoHash& HashKey, const ZenCacheValue& Value)
+{
+	CacheBucket* Bucket = nullptr;
+
+	{
+		RwLock::SharedLockScope _(m_Lock);
+
+		auto it = m_Buckets.find(std::string(InBucket));
+
+		if (it != m_Buckets.end())
+		{
+			Bucket = &it->second;
+		}
+	}
+
+	if (Bucket == nullptr)
+	{
+		// New bucket
+
+		RwLock::ExclusiveLockScope _(m_Lock);
+
+		Bucket = &m_Buckets[std::string(InBucket)];
+	}
+
+	ZEN_ASSERT(Bucket != nullptr);
+
+	Bucket->Put(HashKey, Value);
+}
+
+bool
+ZenCacheMemoryLayer::CacheBucket::Get(const zen::IoHash& HashKey, ZenCacheValue& OutValue)
+{
+	RwLock::SharedLockScope _(m_bucketLock);
+
+	auto bucketIt = m_cacheMap.find(HashKey);
+
+	if (bucketIt == m_cacheMap.end())
+	{
+		return false;
+	}
+
+	OutValue.Value = bucketIt->second;
+
+	return true;
+}
+
+void
+ZenCacheMemoryLayer::CacheBucket::Put(const zen::IoHash& HashKey, const ZenCacheValue& Value)
+{
+	RwLock::ExclusiveLockScope _(m_bucketLock);
+
+	m_cacheMap[HashKey] = Value.Value;
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+#pragma pack(push)
+#pragma pack(1)
+
+struct DiskLocation
+{
+	uint64_t Offset;
+	uint32_t Size;
+};
+
+struct DiskIndexEntry
+{
+	zen::IoHash	 Key;
+	DiskLocation Location;
+};
+
+#pragma pack(pop)
+
+static_assert(sizeof(DiskIndexEntry) == 32);
+
+struct ZenCacheDiskLayer::CacheBucket
+{
+	CacheBucket(CasStore& Cas);
+	~CacheBucket();
+
+	void OpenOrCreate(std::filesystem::path BucketDir);
+
+	bool Get(const zen::IoHash& HashKey, ZenCacheValue& OutValue);
+	void Put(const zen::IoHash& HashKey, const ZenCacheValue& Value);
+	void Flush();
+
+	inline bool IsOk() const { return m_Ok; }
+
+private:
+	CasStore&			  m_CasStore;
+	std::filesystem::path m_BucketDir;
+	Oid					  m_BucketId;
+	bool				  m_Ok					 = false;
+	uint64_t			  m_LargeObjectThreshold = 1024;
+
+	BasicFile					m_SobsFile;
+	TCasLogFile<DiskIndexEntry> m_SlogFile;
+	BasicFile					m_SidxFile;
+
+	void BuildPath(zen::WideStringBuilderBase& Path, const zen::IoHash& HashKey);
+	void PutLargeObject(const zen::IoHash& HashKey, const ZenCacheValue& Value);
+
+	RwLock															   m_IndexLock;
+	std::unordered_map<zen::IoHash, DiskLocation, zen::IoHash::Hasher> m_Index;
+	uint64_t														   m_WriteCursor = 0;
+};
+
+ZenCacheDiskLayer::CacheBucket::CacheBucket(CasStore& Cas) : m_CasStore(Cas)
+{
+}
+
+ZenCacheDiskLayer::CacheBucket::~CacheBucket()
+{
+}
+
+void
+ZenCacheDiskLayer::CacheBucket::OpenOrCreate(std::filesystem::path BucketDir)
+{
+	std::filesystem::create_directories(BucketDir);
+
+	m_BucketDir = BucketDir;
+
+	std::filesystem::path ManifestPath{m_BucketDir / "zen_manifest"};
+	std::filesystem::path SobsPath{m_BucketDir / "zen.sobs"};
+	std::filesystem::path SlogPath{m_BucketDir / "zen.slog"};
+	std::filesystem::path SidxPath{m_BucketDir / "zen.sidx"};
+
+	CAtlFile ManifestFile;
+
+	// Try opening existing file first
+
+	bool IsNew = false;
+
+	HRESULT hRes = ManifestFile.Create(ManifestPath.c_str(), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ, OPEN_EXISTING);
+
+	if (SUCCEEDED(hRes))
+	{
+		ULONGLONG FileSize;
+		ManifestFile.GetSize(FileSize);
+
+		if (FileSize == sizeof(Oid))
+		{
+			hRes = ManifestFile.Read(&m_BucketId, sizeof(Oid));
+
+			if (SUCCEEDED(hRes))
+			{
+				m_Ok = true;
+			}
+		}
+
+		if (!m_Ok)
+			ManifestFile.Close();
+	}
+
+	if (!m_Ok)
+	{
+		// This is a new bucket
+
+		hRes = ManifestFile.Create(ManifestPath.c_str(), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ, CREATE_ALWAYS);
+
+		if (FAILED(hRes))
+		{
+			ThrowLastError("Failed to create bucket manifest '{}'"_format(ManifestPath));
+		}
+
+		m_BucketId.Generate();
+
+		hRes = ManifestFile.Write(&m_BucketId, sizeof(Oid));
+
+		IsNew = true;
+	}
+
+	// Initialize small object storage related files
+
+	m_SobsFile.Open(SobsPath, IsNew);
+	m_SidxFile.Open(SidxPath, IsNew);
+
+	// Open and replay log
+
+	m_SlogFile.Open(SlogPath, IsNew);
+
+	uint64_t MaxFileOffset = 0;
+
+	{
+		// This is not technically necessary but may help future static analysis
+		zen::RwLock::ExclusiveLockScope _(m_IndexLock);
+
+		m_SlogFile.Replay([&](const DiskIndexEntry& Record) {
+			m_Index[Record.Key] = Record.Location;
+
+			MaxFileOffset = std::max<uint64_t>(MaxFileOffset, Record.Location.Offset + Record.Location.Size);
+		});
+	}
+
+	m_WriteCursor = (MaxFileOffset + 15) & ~15;
+
+	m_Ok = true;
+}
+
+void
+ZenCacheDiskLayer::CacheBucket::BuildPath(zen::WideStringBuilderBase& Path, const zen::IoHash& HashKey)
+{
+	char hex[sizeof(HashKey.Hash) * 2];
+	ToHexBytes(HashKey.Hash, sizeof HashKey.Hash, hex);
+
+	Path.Append(m_BucketDir.c_str());
+	Path.Append(L"/");
+	Path.AppendAsciiRange(hex, hex + sizeof(hex));
+}
+
+bool
+ZenCacheDiskLayer::CacheBucket::Get(const zen::IoHash& HashKey, ZenCacheValue& OutValue)
+{
+	if (!m_Ok)
+		return false;
+
+	{
+		zen::RwLock::SharedLockScope _(m_IndexLock);
+
+		if (auto it = m_Index.find(HashKey); it != m_Index.end())
+		{
+			OutValue.Value = IoBufferBuilder::MakeFromFileHandle(m_SobsFile.Handle(), it->second.Offset, it->second.Size);
+
+			return true;
+		}
+	}
+
+	WideStringBuilder<128> DataFilePath;
+	BuildPath(DataFilePath, HashKey);
+
+	zen::IoBuffer Data = IoBufferBuilder::MakeFromFile(DataFilePath.c_str());
+
+	if (!Data)
+	{
+		return false;
+	}
+
+	OutValue.Value = Data;
+
+	// TODO: should populate index?
+
+	return true;
+}
+
+void
+ZenCacheDiskLayer::CacheBucket::Put(const zen::IoHash& HashKey, const ZenCacheValue& Value)
+{
+	if (!m_Ok)
+	{
+		return;
+	}
+
+	if (Value.Value.Size() >= m_LargeObjectThreshold)
+	{
+		return PutLargeObject(HashKey, Value);
+	}
+
+	// Small object put
+
+	zen::RwLock::ExclusiveLockScope _(m_IndexLock);
+
+	auto it = m_Index.find(HashKey);
+
+	DiskLocation Loc{.Offset = m_WriteCursor, .Size = gsl::narrow<uint32_t>(Value.Value.Size())};
+
+	m_WriteCursor = (m_WriteCursor + Loc.Size + 15) & ~15;
+
+	if (it == m_Index.end())
+	{
+		m_Index.insert({HashKey, Loc});
+	}
+	else
+	{
+		// TODO: should check if write is idempotent and bail out if it is?
+
+		it->second = Loc;
+	}
+
+	DiskIndexEntry IndexEntry{.Key = HashKey, .Location = Loc};
+
+	m_SlogFile.Append(IndexEntry);
+
+	m_SobsFile.Write(Value.Value.Data(), Loc.Size, Loc.Offset);
+
+	return;
+}
+
+void
+ZenCacheDiskLayer::CacheBucket::Flush()
+{
+	m_SobsFile.Flush();
+	m_SidxFile.Flush();
+	m_SlogFile.Flush();
+}
+
+void
+ZenCacheDiskLayer::CacheBucket::PutLargeObject(const zen::IoHash& HashKey, const ZenCacheValue& Value)
+{
+	zen::WideStringBuilder<128> DataFilePath;
+	BuildPath(DataFilePath, HashKey);
+
+	// TODO: replace this with a more efficient implementation with proper atomic rename
+
+	CAtlTemporaryFile DataFile;
+
+	HRESULT hRes = DataFile.Create(m_BucketDir.c_str());
+
+	if (FAILED(hRes))
+	{
+		zen::ThrowSystemException(hRes, "Failed to open temporary file for put at '{}'"_format(m_BucketDir));
+	}
+
+	hRes = DataFile.Write(Value.Value.Data(), gsl::narrow<DWORD>(Value.Value.Size()));
+
+	if (FAILED(hRes))
+	{
+		zen::ThrowSystemException(hRes, "Failed to write payload ({} bytes) to file"_format(NiceBytes(Value.Value.Size())));
+	}
+
+	hRes = DataFile.Close(DataFilePath.c_str());
+
+	if (FAILED(hRes))
+	{
+		zen::ThrowSystemException(hRes, "Failed to finalize file '{}'"_format(zen::WideToUtf8(DataFilePath)));
+	}
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+ZenCacheDiskLayer::ZenCacheDiskLayer(CasStore& Cas, const std::filesystem::path& RootDir) : m_RootDir(RootDir), m_CasStore(Cas)
+{
+}
+
+ZenCacheDiskLayer::~ZenCacheDiskLayer() = default;
+
+bool
+ZenCacheDiskLayer::Get(std::string_view InBucket, const zen::IoHash& HashKey, ZenCacheValue& OutValue)
+{
+	CacheBucket* Bucket = nullptr;
+
+	{
+		zen::RwLock::SharedLockScope _(m_Lock);
+
+		auto it = m_Buckets.find(std::string(InBucket));
+
+		if (it != m_Buckets.end())
+		{
+			Bucket = &it->second;
+		}
+	}
+
+	if (Bucket == nullptr)
+	{
+		// Bucket needs to be opened/created
+
+		zen::RwLock::ExclusiveLockScope _(m_Lock);
+
+		auto It = m_Buckets.try_emplace(std::string(InBucket), m_CasStore);
+		Bucket	= &It.first->second;
+
+		std::filesystem::path BucketPath = m_RootDir;
+		BucketPath /= std::string(InBucket);
+
+		Bucket->OpenOrCreate(BucketPath.c_str());
+	}
+
+	ZEN_ASSERT(Bucket != nullptr);
+
+	return Bucket->Get(HashKey, OutValue);
+}
+
+void
+ZenCacheDiskLayer::Put(std::string_view InBucket, const zen::IoHash& HashKey, const ZenCacheValue& Value)
+{
+	CacheBucket* Bucket = nullptr;
+
+	{
+		zen::RwLock::SharedLockScope _(m_Lock);
+
+		auto it = m_Buckets.find(std::string(InBucket));
+
+		if (it != m_Buckets.end())
+		{
+			Bucket = &it->second;
+		}
+	}
+
+	if (Bucket == nullptr)
+	{
+		// New bucket needs to be created
+
+		zen::RwLock::ExclusiveLockScope _(m_Lock);
+
+		auto It = m_Buckets.try_emplace(std::string(InBucket), m_CasStore);
+		Bucket	= &It.first->second;
+
+		std::filesystem::path bucketPath = m_RootDir;
+		bucketPath /= std::string(InBucket);
+
+		Bucket->OpenOrCreate(bucketPath.c_str());
+	}
+
+	ZEN_ASSERT(Bucket != nullptr);
+
+	if (Bucket->IsOk())
+	{
+		Bucket->Put(HashKey, Value);
+	}
+}
+
+void
+ZenCacheDiskLayer::Flush()
+{
+	std::vector<CacheBucket*> Buckets;
+	Buckets.reserve(m_Buckets.size());
+
+	{
+		zen::RwLock::SharedLockScope _(m_Lock);
+
+		for (auto& Kv : m_Buckets)
+		{
+			Buckets.push_back(&Kv.second);
+		}
+	}
+
+	for (auto& Bucket : Buckets)
+	{
+		Bucket->Flush();
+	}
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+ZenCacheTracker::ZenCacheTracker(ZenCacheStore& CacheStore)
+{
+	ZEN_UNUSED(CacheStore);
+}
+
+ZenCacheTracker::~ZenCacheTracker()
+{
+}
+
+void
+ZenCacheTracker::TrackAccess(std::string_view Bucket, const zen::IoHash& HashKey)
+{
+	ZEN_UNUSED(Bucket);
+	ZEN_UNUSED(HashKey);
+}
+
+void
+ZenCacheTracker::Flush()
+{
+}