visit_each_entry_in_map.h

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// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the Apache 2.0 License.
#pragma once
 
#include "ccf/byte_vector.h"
#include "ccf/indexing/strategy.h"
#include "ccf/pal/locking.h"
 
namespace ccf::indexing::strategies
{
  // A meta-strategy which takes a target map, requests every Tx in-order, and
  // visits each written KV pair in the target map in each Tx. Derived classes
  // override visit_entry() to construct/store their index.
  class VisitEachEntryInMap : public Strategy
  {
  protected:
    std::string map_name;
 
    // Protect access to current_txid
    ccf::pal::Mutex current_txid_lock;
 
    ccf::TxID current_txid = {};
 
    virtual void visit_entry(
      const ccf::TxID& tx_id,
      const ccf::ByteVector& k,
      const ccf::ByteVector& v) = 0;
 
  public:
    VisitEachEntryInMap(
      const std::string& map_name_,
      const std::string& strategy_prefix = "VisitEachEntryIn");
 
    virtual ~VisitEachEntryInMap() = default;
 
    void handle_committed_transaction(
      const ccf::TxID& tx_id, const ccf::kv::ReadOnlyStorePtr& store) override;
    std::optional<ccf::SeqNo> next_requested() override;
 
    nlohmann::json describe() override;
 
    ccf::TxID get_indexed_watermark();
  };
}