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#include "sync_page_cache_file.h"
#include "record.h"
#include <util/generic/buffer.h>
#include <util/system/file.h>
#include <util/system/info.h>
#include <util/system/mutex.h>
#include <util/system/align.h>
class TSyncPageCacheFileLogBackend::TImpl: public TNonCopyable {
public:
TImpl(const TString& path, size_t maxBufferSize, size_t maxPendingCacheSize)
: File_{OpenFile(path)}
, MaxBufferSize_{maxBufferSize}
, MaxPendingCacheSize_{maxPendingCacheSize}
, Buffer_{maxBufferSize}
{
ResetPtrs();
}
~TImpl() noexcept {
try {
Write();
FlushSync(GuaranteedWrittenPtr_, WrittenPtr_);
} catch (...) {
}
}
void WriteData(const TLogRecord& rec) {
TGuard guard{Lock_};
Buffer_.Append(rec.Data, rec.Len);
if (Buffer_.size() >= MaxBufferSize_) {
const i64 prevAlignedEndPtr = PageAlignedWrittenPtr_;
Write();
if (prevAlignedEndPtr < PageAlignedWrittenPtr_) {
FlushAsync(prevAlignedEndPtr, PageAlignedWrittenPtr_);
}
const i64 minPendingCacheOffset = PageAlignedWrittenPtr_ - MaxPendingCacheSize_;
if (minPendingCacheOffset > GuaranteedWrittenPtr_) {
FlushSync(GuaranteedWrittenPtr_, minPendingCacheOffset);
}
}
}
void ReopenLog() {
TGuard guard{Lock_};
Write();
FlushSync(GuaranteedWrittenPtr_, WrittenPtr_);
File_.LinkTo(OpenFile(File_.GetName()));
ResetPtrs();
}
private:
void ResetPtrs() {
WrittenPtr_ = File_.GetLength();
PageAlignedWrittenPtr_ = AlignDown(WrittenPtr_, GetPageSize());
GuaranteedWrittenPtr_ = WrittenPtr_;
}
static TFile OpenFile(const TString& path) {
return TFile{path, OpenAlways | WrOnly | ForAppend | Seq | NoReuse};
}
static i64 GetPageSize() {
static const i64 pageSize = NSystemInfo::GetPageSize();
Y_ASSUME(IsPowerOf2(pageSize));
return pageSize;
}
void Write() {
File_.Write(Buffer_.Data(), Buffer_.Size());
WrittenPtr_ += Buffer_.Size();
PageAlignedWrittenPtr_ = AlignDown(WrittenPtr_, GetPageSize());
Buffer_.Clear();
}
void FlushAsync(const i64 from, const i64 to) {
File_.FlushCache(from, to - from, /* wait = */ false);
}
void FlushSync(const i64 from, const i64 to) {
const i64 begin = AlignDown(from, GetPageSize());
const i64 end = AlignUp(to, GetPageSize());
const i64 length = end - begin;
File_.FlushCache(begin, length, /* wait = */ true);
File_.EvictCache(begin, length);
GuaranteedWrittenPtr_ = to;
}
private:
TMutex Lock_;
TFile File_;
const size_t MaxBufferSize_ = 0;
const size_t MaxPendingCacheSize_ = 0;
TBuffer Buffer_;
i64 WrittenPtr_ = 0;
i64 PageAlignedWrittenPtr_ = 0;
i64 GuaranteedWrittenPtr_ = 0;
};
TSyncPageCacheFileLogBackend::TSyncPageCacheFileLogBackend(const TString& path, size_t maxBufferSize, size_t maxPengingCacheSize)
: Impl_(MakeHolder<TImpl>(path, maxBufferSize, maxPengingCacheSize))
{}
TSyncPageCacheFileLogBackend::~TSyncPageCacheFileLogBackend() {
}
void TSyncPageCacheFileLogBackend::WriteData(const TLogRecord& rec) {
Impl_->WriteData(rec);
}
void TSyncPageCacheFileLogBackend::ReopenLog() {
Impl_->ReopenLog();
}
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