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// Copyright Epic Games, Inc. All Rights Reserved.
#include "cachetracking.h"
#include <zencore/filesystem.h>
#include <zencore/logging.h>
#include <zencore/string.h>
#include <zencore/testing.h>
#include <zencore/testutils.h>
ZEN_THIRD_PARTY_INCLUDES_START
#pragma comment(lib, "Rpcrt4.lib") // RocksDB made me do this
#include <fmt/format.h>
#include <rocksdb/db.h>
ZEN_THIRD_PARTY_INCLUDES_END
namespace zen {
using namespace fmt::literals;
namespace rocksdb = ROCKSDB_NAMESPACE;
static constinit auto Epoch = std::chrono::time_point<std::chrono::system_clock>{};
uint32_t
GetCurrentTimeStamp()
{
auto Duration = std::chrono::system_clock::now() - Epoch;
auto Minutes = std::chrono::duration_cast<std::chrono::minutes>(Duration).count();
return Minutes;
}
struct ZenCacheTracker::Impl
{
Impl(std::filesystem::path StateDirectory)
{
std::filesystem::path StatsDbPath{StateDirectory / ".zdb"};
std::string RocksdbPath = ToUtf8(StatsDbPath);
ZEN_DEBUG("opening tracker db at '{}'", RocksdbPath);
rocksdb::DB* Db = nullptr;
rocksdb::DBOptions Options;
Options.create_if_missing = true;
std::vector<std::string> ExistingColumnFamilies;
rocksdb::Status Status = rocksdb::DB::ListColumnFamilies(Options, RocksdbPath, &ExistingColumnFamilies);
std::vector<rocksdb::ColumnFamilyDescriptor> ColumnDescriptors;
if (Status.IsPathNotFound())
{
ColumnDescriptors.emplace_back(rocksdb::ColumnFamilyDescriptor{rocksdb::kDefaultColumnFamilyName, {}});
}
else if (Status.ok())
{
for (const std::string& Column : ExistingColumnFamilies)
{
rocksdb::ColumnFamilyDescriptor ColumnFamily;
ColumnFamily.name = Column;
ColumnDescriptors.push_back(ColumnFamily);
}
}
else
{
throw std::runtime_error("column family iteration failed for '{}': '{}'"_format(RocksdbPath, Status.getState()).c_str());
}
Status = rocksdb::DB::Open(Options, RocksdbPath, ColumnDescriptors, &m_RocksDbColumnHandles, &Db);
if (!Status.ok())
{
throw std::runtime_error("database open failed for '{}': '{}'"_format(RocksdbPath, Status.getState()).c_str());
}
m_RocksDb.reset(Db);
}
~Impl()
{
for (auto* Column : m_RocksDbColumnHandles)
{
delete Column;
}
m_RocksDbColumnHandles.clear();
}
struct KeyStruct
{
uint16_t BucketId;
IoHash HashKey;
};
struct ValueStruct
{
uint32_t CreateTime = 0;
uint32_t AccessTime = 0;
uint32_t AccessCount = 0;
uint32_t LastGcCount = 0;
};
void TrackAccess(std::string_view BucketSegment, const IoHash& HashKey)
{
const uint32_t Ts = GetCurrentTimeStamp();
rocksdb::WriteOptions Wo;
rocksdb::ReadOptions Ro;
ZEN_UNUSED(BucketSegment);
ValueStruct Value;
rocksdb::Slice ValueSlice{(char*)&Value, sizeof Value};
KeyStruct Key;
Key.BucketId = 0;
Key.HashKey = HashKey;
rocksdb::Slice KeySlice{(char*)&Key, sizeof Key};
std::string ValueString;
rocksdb::Status Status = m_RocksDb->Get(Ro, KeySlice, &ValueString);
if (Status.ok() && ValueString.size() == sizeof(ValueStruct))
{
memcpy(&Value, ValueString.data(), ValueString.size());
++Value.AccessCount;
}
else
{
Value.CreateTime = Ts;
Value.AccessCount = 1;
}
Value.AccessTime = Ts;
m_RocksDb->Put(Wo, KeySlice, ValueSlice);
}
std::unique_ptr<rocksdb::DB> m_RocksDb;
std::vector<rocksdb::ColumnFamilyHandle*> m_RocksDbColumnHandles;
};
ZenCacheTracker::ZenCacheTracker(std::filesystem::path StateDirectory) : m_Impl(new Impl(StateDirectory))
{
}
ZenCacheTracker::~ZenCacheTracker()
{
delete m_Impl;
}
void
ZenCacheTracker::TrackAccess(std::string_view BucketSegment, const IoHash& HashKey)
{
m_Impl->TrackAccess(BucketSegment, HashKey);
}
#if ZEN_WITH_TESTS
TEST_CASE("z$.tracker")
{
using namespace fmt::literals;
using namespace std::literals;
ScopedTemporaryDirectory TempDir;
ZenCacheTracker Zcs(TempDir.Path());
for (int i = 0; i < 10000; ++i)
{
IoHash KeyHash = IoHash::HashBuffer(&i, sizeof i);
Zcs.TrackAccess("foo", KeyHash);
}
for (int i = 0; i < 10000; ++i)
{
IoHash KeyHash = IoHash::HashBuffer(&i, sizeof i);
Zcs.TrackAccess("foo", KeyHash);
}
}
#endif
void
cachetracker_forcelink()
{
}
} // namespace zen
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