Method getFileSize

test/transaction/wal_test.cpp:127–131

    }

    uint64_t getFileSize(const FileInfo& fileInfo) const override {
        std::unique_lock lck{mtx};
        const auto file = files.find(fileInfo.path);
        return file == files.end() ? 0 : file->second.size();
    }

private:
    bool failSync;