rocksdb/include/leveldb/transaction_log_iterator.h

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// Copyright 2008-present Facebook. All Rights Reserved.
#ifndef STORAGE_LEVELDB_INCLUDE_TRANSACTION_LOG_ITERATOR_H_
#define STORAGE_LEVELDB_INCLUDE_TRANSACTION_LOG_ITERATOR_H_
#include "leveldb/status.h"
#include "leveldb/write_batch.h"
namespace leveldb {
struct BatchResult {
SequenceNumber sequence;
std::unique_ptr<WriteBatch> writeBatchPtr;
};
// A TransactionLogIterator is used to iterate over the Transaction's in a db.
class TransactionLogIterator {
public:
TransactionLogIterator() {}
virtual ~TransactionLogIterator() {}
// An iterator is either positioned at a WriteBatch or not valid.
// This method returns true if the iterator is valid.
// Can read data from a valid iterator.
virtual bool Valid() = 0;
// Moves the iterator to the next WriteBatch.
// REQUIRES: Valid() to be true.
virtual void Next() = 0;
// Return's ok if the iterator is valid.
// Return the Error when something has gone wrong.
virtual Status status() = 0;
// If valid return's the current write_batch and the sequence number of the
// latest transaction contained in the batch.
// ONLY use if Valid() is true and status() is OK.
virtual BatchResult GetBatch() = 0;
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_INCLUDE_TRANSACTION_LOG_ITERATOR_H_