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

1 files changed, 117 insertions, 0 deletions

diff --git a/zenserver/cache/structuredcachestore.h b/zenserver/cache/structuredcachestore.h
new file mode 100644
index 000000000..7936f9d84
--- /dev/null
+++ b/zenserver/cache/structuredcachestore.h
@@ -0,0 +1,117 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#pragma once
+
+#include <zencore/IoBuffer.h>
+#include <zencore/iohash.h>
+#include <zencore/thread.h>
+#include <zencore/uid.h>
+#include <zenstore/cas.h>
+#include <compare>
+#include <filesystem>
+#include <unordered_map>
+
+namespace zen {
+
+class WideStringBuilderBase;
+class CasStore;
+
+}  // namespace zen
+
+/******************************************************************************
+
+  /$$$$$$$$                        /$$$$$$                   /$$
+ |_____ $$                        /$$__  $$                 | $$
+	  /$$/  /$$$$$$ /$$$$$$$     | $$  \__/ /$$$$$$  /$$$$$$| $$$$$$$  /$$$$$$
+	 /$$/  /$$__  $| $$__  $$    | $$      |____  $$/$$_____| $$__  $$/$$__  $$
+	/$$/  | $$$$$$$| $$  \ $$    | $$       /$$$$$$| $$     | $$  \ $| $$$$$$$$
+   /$$/   | $$_____| $$  | $$    | $$    $$/$$__  $| $$     | $$  | $| $$_____/
+  /$$$$$$$|  $$$$$$| $$  | $$    |  $$$$$$|  $$$$$$|  $$$$$$| $$  | $|  $$$$$$$
+ |________/\_______|__/  |__/     \______/ \_______/\_______|__/  |__/\_______/
+
+  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
+{
+	zen::IoBuffer Value;
+	bool		  IsCompactBinary = false;
+};
+
+class ZenCacheMemoryLayer
+{
+public:
+	ZenCacheMemoryLayer();
+	~ZenCacheMemoryLayer();
+
+	bool Get(std::string_view Bucket, const zen::IoHash& HashKey, ZenCacheValue& OutValue);
+	void Put(std::string_view Bucket, const zen::IoHash& HashKey, const ZenCacheValue& Value);
+
+private:
+	struct CacheBucket
+	{
+		zen::RwLock															m_bucketLock;
+		std::unordered_map<zen::IoHash, zen::IoBuffer, zen::IoHash::Hasher> m_cacheMap;
+
+		bool Get(const zen::IoHash& HashKey, ZenCacheValue& OutValue);
+		void Put(const zen::IoHash& HashKey, const ZenCacheValue& Value);
+	};
+
+	zen::RwLock									 m_Lock;
+	std::unordered_map<std::string, CacheBucket> m_Buckets;
+};
+
+class ZenCacheDiskLayer
+{
+public:
+	ZenCacheDiskLayer(zen::CasStore& Cas, const std::filesystem::path& RootDir);
+	~ZenCacheDiskLayer();
+
+	bool Get(std::string_view Bucket, const zen::IoHash& HashKey, ZenCacheValue& OutValue);
+	void Put(std::string_view Bucket, const zen::IoHash& HashKey, const ZenCacheValue& Value);
+
+	void Flush();
+
+private:
+	/** A cache bucket manages a single directory containing
+		metadata and data for that bucket
+	  */
+	struct CacheBucket;
+
+	zen::CasStore&								 m_CasStore;
+	std::filesystem::path						 m_RootDir;
+	zen::RwLock									 m_Lock;
+	std::unordered_map<std::string, CacheBucket> m_Buckets;	 // TODO: make this case insensitive
+};
+
+class ZenCacheStore
+{
+public:
+	ZenCacheStore(zen::CasStore& Cas, const std::filesystem::path& RootDir);
+	~ZenCacheStore();
+
+	bool Get(std::string_view Bucket, const zen::IoHash& HashKey, ZenCacheValue& OutValue);
+	void Put(std::string_view Bucket, const zen::IoHash& HashKey, const ZenCacheValue& Value);
+
+private:
+	std::filesystem::path m_RootDir;
+	ZenCacheMemoryLayer	  m_MemLayer;
+	ZenCacheDiskLayer	  m_DiskLayer;
+};
+
+/** Tracks cache entry access, stats and orchestrates cleanup activities
+ */
+class ZenCacheTracker
+{
+public:
+	ZenCacheTracker(ZenCacheStore& CacheStore);
+	~ZenCacheTracker();
+
+	void TrackAccess(std::string_view Bucket, const zen::IoHash& HashKey);
+	void Flush();
+
+private:
+};