library/cpp/logger/file.cpp


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#include "file.h" 
#include "record.h" 
 
#include <util/system/file.h> 
#include <util/system/rwlock.h> 
#include <util/generic/string.h>
 
/* 
 * file log 
 */ 
class TFileLogBackend::TImpl {
public: 
    inline TImpl(const TString& path)
        : File_(OpenFile(path)) 
    { 
    } 
 
    inline void WriteData(const TLogRecord& rec) { 
        //many writes are thread-safe 
        TReadGuard guard(Lock_); 
 
        File_.Write(rec.Data, rec.Len); 
    } 
 
    inline void ReopenLog() { 
        //but log rotate not thread-safe 
        TWriteGuard guard(Lock_); 
 
        File_.LinkTo(OpenFile(File_.GetName())); 
    } 
 
private: 
    static inline TFile OpenFile(const TString& path) {
        return TFile(path, OpenAlways | WrOnly | ForAppend | Seq | NoReuse); 
    } 
 
private: 
    TRWMutex Lock_; 
    TFile File_; 
}; 
 
TFileLogBackend::TFileLogBackend(const TString& path)
    : Impl_(new TImpl(path)) 
{ 
} 
 
TFileLogBackend::~TFileLogBackend() {
} 
 
void TFileLogBackend::WriteData(const TLogRecord& rec) { 
    Impl_->WriteData(rec); 
} 
 
void TFileLogBackend::ReopenLog() { 
    TAtomicSharedPtr<TImpl> copy = Impl_;
    if (copy) {
        copy->ReopenLog();
    }
}