event_projector.hpp

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#pragma once
 
#include <array>
#include <cstddef>
#include <cstdint>
#include <optional>
#include <string>
#include <string_view>
 
#include "native.h"
#include <asio.hpp>
 
namespace dcn::events
{
    constexpr std::string_view FEED_PROJECTOR_ID = "feed";
    constexpr std::string_view REGISTRY_PROJECTOR_ID = "registry";
 
    // Bits in normalized_events_hot.dead_letter. A projector sets its bit when it
    // exhausts its retry budget on a row and advances its cursor past it. Rows with
    // any bit set are exempt from pruning, so the raw chain evidence is retained
    // until every marking projector resolves the row and clears its bit.
    constexpr int FEED_DEAD_LETTER_BIT = 1 << 0;
    constexpr int REGISTRY_DEAD_LETTER_BIT = 1 << 1;
 
    // Retry/quarantine tuning shared by the projectors.
    struct ProjectorRetryConfig
    {
        // Consecutive failing passes on the same row before it is dead-lettered and
        // the cursor advances past it. Values <= 1 dead-letter on the first failure.
        std::size_t max_attempts = 5;
 
        // Minimum time between idle-time dead-letter retry sweeps; dead letters are
        // rare, so a slow cadence keeps the recovery path cheap.
        std::int64_t sweep_interval_ms = 60'000;
    };
 
    struct ChangeRecord
    {
        int chain_id = 0;
        std::string block_hash;
        std::int64_t log_index = 0;
        std::int64_t change_seq = 0;
        std::string event_type;
        std::string state;
        std::string name;
        std::string owner;
        std::string tx_hash;
        std::optional<std::int64_t> block_time;
        std::string data_hex;
        std::array<std::optional<std::string>, 4> topics;
        std::int64_t block_number = 0;
        std::int64_t tx_index = 0;
    };
 
    class IEventProjector
    {
        public:
            virtual ~IEventProjector() = default;
            virtual std::string_view id() const = 0;
            virtual std::int64_t cursor() const = 0;
            virtual asio::awaitable<std::size_t> projectBatch(std::size_t limit, std::int64_t now_ms) = 0;
    };
}