nullifier_tree_check.hpp

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#pragma once
 
#include "barretenberg/vm2/common/field.hpp"
#include "barretenberg/vm2/simulation/events/nullifier_tree_check_event.hpp"
#include "barretenberg/vm2/simulation/field_gt.hpp"
#include "barretenberg/vm2/simulation/merkle_check.hpp"
#include "barretenberg/vm2/simulation/poseidon2.hpp"
 
namespace bb::avm2::simulation {
 
class NullifierTreeCheckInterface {
  public:
    virtual ~NullifierTreeCheckInterface() = default;
    virtual void assert_read(const FF& nullifier,
                             std::optional<AztecAddress> contract_address,
                             bool exists,
                             const NullifierTreeLeafPreimage& low_leaf_preimage,
                             uint64_t low_leaf_index,
                             std::span<const FF> sibling_path,
                             const AppendOnlyTreeSnapshot& snapshot) = 0;
    virtual AppendOnlyTreeSnapshot write(const FF& nullifier,
                                         std::optional<AztecAddress> contract_address,
                                         uint64_t nullifier_counter,
                                         const NullifierTreeLeafPreimage& low_leaf_preimage,
                                         uint64_t low_leaf_index,
                                         std::span<const FF> low_leaf_sibling_path,
                                         const AppendOnlyTreeSnapshot& prev_snapshot,
                                         // Null if this is a failing write.
                                         std::optional<std::span<const FF>> insertion_sibling_path) = 0;
};
 
class NullifierTreeCheck : public NullifierTreeCheckInterface, public CheckpointNotifiable {
  public:
    NullifierTreeCheck(Poseidon2Interface& poseidon2,
                       MerkleCheckInterface& merkle_check,
                       FieldGreaterThanInterface& field_gt,
                       EventEmitterInterface<NullifierTreeCheckEvent>& event_emitter)
        : events(event_emitter)
        , poseidon2(poseidon2)
        , merkle_check(merkle_check)
        , field_gt(field_gt)
    {}
 
    void assert_read(const FF& nullifier,
                     std::optional<AztecAddress> contract_address,
                     bool exists,
                     const NullifierTreeLeafPreimage& low_leaf_preimage,
                     uint64_t low_leaf_index,
                     std::span<const FF> sibling_path,
                     const AppendOnlyTreeSnapshot& snapshot) override;
    AppendOnlyTreeSnapshot write(const FF& nullifier,
                                 std::optional<AztecAddress> contract_address,
                                 uint64_t nullifier_counter,
                                 const NullifierTreeLeafPreimage& low_leaf_preimage,
                                 uint64_t low_leaf_index,
                                 std::span<const FF> low_leaf_sibling_path,
                                 const AppendOnlyTreeSnapshot& prev_snapshot,
                                 std::optional<std::span<const FF>> insertion_sibling_path) override;
 
    void on_checkpoint_created() override;
    void on_checkpoint_committed() override;
    void on_checkpoint_reverted() override;
 
  private:
    FF silo_nullifier(const FF& nullifier, AztecAddress contract_address);
    void validate_low_leaf(const FF& nullifier, const NullifierTreeLeafPreimage& low_leaf_preimage, bool exists);
 
    EventEmitterInterface<NullifierTreeCheckEvent>& events;
    Poseidon2Interface& poseidon2;
    MerkleCheckInterface& merkle_check;
    FieldGreaterThanInterface& field_gt;
};
 
} // namespace bb::avm2::simulation