//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.

//  This source code is licensed under both the GPLv2 (found in the

//  COPYING file in the root directory) and Apache 2.0 License

//  (found in the LICENSE.Apache file in the root directory).

#pragma once

#include "utilities/transactions/write_prepared_txn_db.h"

#include "utilities/transactions/write_unprepared_txn.h"

namespace ROCKSDB_NAMESPACE {

class WriteUnpreparedTxn;

class WriteUnpreparedTxnDB : public WritePreparedTxnDB {

 public:

  using WritePreparedTxnDB::WritePreparedTxnDB;

  Status Initialize(const std::vector<size_t>& compaction_enabled_cf_indices,

                    const std::vector<ColumnFamilyHandle*>& handles) override;

  Transaction* BeginTransaction(const WriteOptions& write_options,

                                const TransactionOptions& txn_options,

                                Transaction* old_txn) override;

  // Struct to hold ownership of snapshot and read callback for cleanup.

  struct IteratorState;

  using WritePreparedTxnDB::NewIterator;

  Iterator* NewIterator(const ReadOptions& _read_options,

                        ColumnFamilyHandle* column_family,

                        WriteUnpreparedTxn* txn);

 private:

  Status RollbackRecoveredTransaction(const DBImpl::RecoveredTransaction* rtxn);

};

class WriteUnpreparedCommitEntryPreReleaseCallback : public PreReleaseCallback {

  // TODO(lth): Reduce code duplication with

  // WritePreparedCommitEntryPreReleaseCallback

 public:

  // includes_data indicates that the commit also writes non-empty

  // CommitTimeWriteBatch to memtable, which needs to be committed separately.

  WriteUnpreparedCommitEntryPreReleaseCallback(

      WritePreparedTxnDB* db, DBImpl* db_impl,

      const std::map<SequenceNumber, size_t>& unprep_seqs,

      size_t data_batch_cnt = 0, bool publish_seq = true)

      : db_(db),

        db_impl_(db_impl),

        unprep_seqs_(unprep_seqs),

        data_batch_cnt_(data_batch_cnt),

        includes_data_(data_batch_cnt_ > 0),

        publish_seq_(publish_seq) {

    assert(unprep_seqs.size() > 0);

  }

  Status Callback(SequenceNumber commit_seq,

                  bool is_mem_disabled __attribute__((__unused__)), uint64_t,

                  size_t /*index*/, size_t /*total*/) override {

    const uint64_t last_commit_seq = LIKELY(data_batch_cnt_ <= 1)

                                         ? commit_seq

                                         : commit_seq + data_batch_cnt_ - 1;

    // Recall that unprep_seqs maps (un)prepared_seq => prepare_batch_cnt.

    for (const auto& s : unprep_seqs_) {

      for (size_t i = 0; i < s.second; i++) {

        db_->AddCommitted(s.first + i, last_commit_seq);

      }

    }

    if (includes_data_) {

      assert(data_batch_cnt_);

      // Commit the data that is accompanied with the commit request

      for (size_t i = 0; i < data_batch_cnt_; i++) {

        // For commit seq of each batch use the commit seq of the last batch.

        // This would make debugging easier by having all the batches having

        // the same sequence number.

        db_->AddCommitted(commit_seq + i, last_commit_seq);

      }

    }

    if (db_impl_->immutable_db_options().two_write_queues && publish_seq_) {

      assert(is_mem_disabled);  // implies the 2nd queue

      // Publish the sequence number. We can do that here assuming the callback

      // is invoked only from one write queue, which would guarantee that the

      // publish sequence numbers will be in order, i.e., once a seq is

      // published all the seq prior to that are also publishable.

      db_impl_->SetLastPublishedSequence(last_commit_seq);

    }

    // else SequenceNumber that is updated as part of the write already does the

    // publishing

    return Status::OK();

  }

 private:

  WritePreparedTxnDB* db_;

  DBImpl* db_impl_;

  const std::map<SequenceNumber, size_t>& unprep_seqs_;

  size_t data_batch_cnt_;

  // Either because it is commit without prepare or it has a

  // CommitTimeWriteBatch

  bool includes_data_;

  // Should the callback also publishes the commit seq number

  bool publish_seq_;

};

}  // namespace ROCKSDB_NAMESPACE