cp_handler.hpp

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//---------------------------------------------------------------------------//
// Copyright (c) 2018-2021 Mikhail Komarov <nemo@nil.foundation>
// Copyright (c) 2020-2021 Nikita Kaskov <nbering@nil.foundation>
//
// MIT License
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//---------------------------------------------------------------------------//
// @file Declaration of interfaces for a compliance predicate handler.
//
// A compliance predicate handler is a base class for creating compliance predicates.
// It relies on classes declared in components.
//---------------------------------------------------------------------------//
 
#ifndef CRYPTO3_ZK_BLUEPRINT_CP_HANDLER_HPP
#define CRYPTO3_ZK_BLUEPRINT_CP_HANDLER_HPP
 
#include <numeric>
 
#include <nil/crypto3/zk/components/component.hpp>
#include <nil/crypto3/zk/components/blueprint.hpp>
 
#include <nil/crypto3/zk/snark/schemes/pcd/r1cs_pcd/compliance_predicate.hpp>
 
namespace nil {
    namespace crypto3 {
        namespace zk {
            namespace snark {
 
                /***************************** Message variable ******************************/
 
                template<typename FieldType>
                class r1cs_pcd_message_variable : public components::component<FieldType> {
                protected:
                    std::size_t num_vars_at_construction;
 
                public:
                    blueprint_variable<FieldType> type;
 
                    blueprint_variable_vector<FieldType> all_vars;
 
                    r1cs_pcd_message_variable(blueprint<FieldType> &bp);
                    void update_all_vars();
 
                    void generate_r1cs_witness(const std::shared_ptr<r1cs_pcd_message<FieldType>> &message);
                    virtual std::shared_ptr<r1cs_pcd_message<FieldType>> get_message() const = 0;
 
                    virtual ~r1cs_pcd_message_variable() = default;
                };
                /*************************** Local data variable *****************************/
 
                template<typename FieldType>
                class r1cs_pcd_local_data_variable : public components::component<FieldType> {
                protected:
                    std::size_t num_vars_at_construction;
 
                public:
                    blueprint_variable_vector<FieldType> all_vars;
 
                    r1cs_pcd_local_data_variable(blueprint<FieldType> &bp);
                    void update_all_vars();
 
                    void generate_r1cs_witness(const std::shared_ptr<r1cs_pcd_local_data<FieldType>> &local_data);
 
                    virtual ~r1cs_pcd_local_data_variable() = default;
                };
 
                /*********************** Compliance predicate handler ************************/
 
                template<typename FieldType, typename BlueprintType>
                class compliance_predicate_handler {
                protected:
                    BlueprintType bp;
 
                    std::shared_ptr<r1cs_pcd_message_variable<FieldType>> outgoing_message;
                    blueprint_variable<FieldType> arity;
                    std::vector<std::shared_ptr<r1cs_pcd_message_variable<FieldType>>> incoming_messages;
                    std::shared_ptr<r1cs_pcd_local_data_variable<FieldType>> local_data;
 
                public:
                    const std::size_t name;
                    const std::size_t type;
                    const std::size_t max_arity;
                    const bool relies_on_same_type_inputs;
                    const std::set<std::size_t> accepted_input_types;
 
                    compliance_predicate_handler(
                        const BlueprintType &bp,
                        const std::size_t name,
                        const std::size_t type,
                        const std::size_t max_arity,
                        const bool relies_on_same_type_inputs,
                        const std::set<std::size_t> &accepted_input_types = std::set<std::size_t>());
                    virtual void generate_r1cs_constraints() = 0;
                    virtual void generate_r1cs_witness(
                        const std::vector<std::shared_ptr<r1cs_pcd_message<FieldType>>> &incoming_message_values,
                        const std::shared_ptr<r1cs_pcd_local_data<FieldType>> &local_data_value);
 
                    r1cs_pcd_compliance_predicate<FieldType> get_compliance_predicate() const;
                    snark::r1cs_variable_assignment<FieldType> get_full_variable_assignment() const;
 
                    std::shared_ptr<r1cs_pcd_message<FieldType>> get_outgoing_message() const;
                    std::size_t get_arity() const;
                    std::shared_ptr<r1cs_pcd_message<FieldType>>
                        get_incoming_message(const std::size_t message_idx) const;
                    std::shared_ptr<r1cs_pcd_local_data<FieldType>> get_local_data() const;
                    snark::r1cs_variable_assignment<FieldType> get_witness() const;
                };
 
                template<typename FieldType>
                r1cs_pcd_message_variable<FieldType>::r1cs_pcd_message_variable(blueprint<FieldType> &bp) :
                    components::component<FieldType>(bp) {
                    type.allocate(bp);
                    all_vars.emplace_back(type);
 
                    num_vars_at_construction = bp.num_variables();
                }
 
                template<typename FieldType>
                void r1cs_pcd_message_variable<FieldType>::update_all_vars() {
                    /* NOTE: this assumes that r1cs_pcd_message_variable has been the
                     * only component allocating variables on the protoboard and needs to
                     * be updated, e.g., in multicore variable allocation scenario. */
 
                    for (std::size_t var_idx = num_vars_at_construction + 1; var_idx <= this->bp.num_variables();
                         ++var_idx) {
                        all_vars.emplace_back(blueprint_variable<FieldType>(var_idx));
                    }
                }
 
                template<typename FieldType>
                void r1cs_pcd_message_variable<FieldType>::generate_r1cs_witness(
                    const std::shared_ptr<r1cs_pcd_message<FieldType>> &message) {
                    all_vars.fill_with_field_elements(this->bp, message->as_r1cs_variable_assignment());
                }
 
                template<typename FieldType>
                r1cs_pcd_local_data_variable<FieldType>::r1cs_pcd_local_data_variable(blueprint<FieldType> &bp) :
                    components::component<FieldType>(bp) {
                    num_vars_at_construction = bp.num_variables();
                }
 
                template<typename FieldType>
                void r1cs_pcd_local_data_variable<FieldType>::update_all_vars() {
                    /* (the same NOTE as for r1cs_message_variable applies) */
 
                    for (std::size_t var_idx = num_vars_at_construction + 1; var_idx <= this->bp.num_variables();
                         ++var_idx) {
                        all_vars.emplace_back(blueprint_variable<FieldType>(var_idx));
                    }
                }
 
                template<typename FieldType>
                void r1cs_pcd_local_data_variable<FieldType>::generate_r1cs_witness(
                    const std::shared_ptr<r1cs_pcd_local_data<FieldType>> &local_data) {
                    all_vars.fill_with_field_elements(this->bp, local_data->as_r1cs_variable_assignment());
                }
 
                template<typename FieldType, typename BlueprintType>
                compliance_predicate_handler<FieldType, BlueprintType>::compliance_predicate_handler(
                    const BlueprintType &bp,
                    const std::size_t name,
                    const std::size_t type,
                    const std::size_t max_arity,
                    const bool relies_on_same_type_inputs,
                    const std::set<std::size_t> &accepted_input_types) :
                    bp(bp),
                    name(name), type(type), max_arity(max_arity),
                    relies_on_same_type_inputs(relies_on_same_type_inputs), accepted_input_types(accepted_input_types) {
                    incoming_messages.resize(max_arity);
                }
 
                template<typename FieldType, typename BlueprintType>
                void compliance_predicate_handler<FieldType, BlueprintType>::generate_r1cs_witness(
                    const std::vector<std::shared_ptr<r1cs_pcd_message<FieldType>>> &incoming_message_values,
                    const std::shared_ptr<r1cs_pcd_local_data<FieldType>> &local_data_value) {
                    bp.clear_values();
                    bp.val(outgoing_message->type) = typename FieldType::value_type(type);
                    bp.val(arity) = typename FieldType::value_type(incoming_message_values.size());
 
                    for (std::size_t i = 0; i < incoming_message_values.size(); ++i) {
                        incoming_messages[i]->generate_r1cs_witness(incoming_message_values[i]);
                    }
 
                    local_data->generate_r1cs_witness(local_data_value);
                }
 
                template<typename FieldType, typename BlueprintType>
                r1cs_pcd_compliance_predicate<FieldType>
                    compliance_predicate_handler<FieldType, BlueprintType>::get_compliance_predicate() const {
                    assert(incoming_messages.size() == max_arity);
 
                    const std::size_t outgoing_message_payload_length = outgoing_message->all_vars.size() - 1;
 
                    std::vector<std::size_t> incoming_message_payload_lengths(max_arity);
                    std::transform(incoming_messages.begin(), incoming_messages.end(),
                                   incoming_message_payload_lengths.begin(),
                                   [](const std::shared_ptr<r1cs_pcd_message_variable<FieldType>> &msg) {
                                       return msg->all_vars.size() - 1;
                                   });
 
                    const std::size_t local_data_length = local_data->all_vars.size();
 
                    const std::size_t all_but_witness_length =
                        ((1 + outgoing_message_payload_length) + 1 +
                         (max_arity + std::accumulate(incoming_message_payload_lengths.begin(),
                                                      incoming_message_payload_lengths.end(), 0)) +
                         local_data_length);
                    const std::size_t witness_length = bp.num_variables() - all_but_witness_length;
 
                    snark::r1cs_constraint_system<FieldType> constraint_system = bp.get_constraint_system();
                    constraint_system.primary_input_size = 1 + outgoing_message_payload_length;
                    constraint_system.auxiliary_input_size = bp.num_variables() - constraint_system.primary_input_size;
 
                    return r1cs_pcd_compliance_predicate<FieldType>(name,
                                                                    type,
                                                                    constraint_system,
                                                                    outgoing_message_payload_length,
                                                                    max_arity,
                                                                    incoming_message_payload_lengths,
                                                                    local_data_length,
                                                                    witness_length,
                                                                    relies_on_same_type_inputs,
                                                                    accepted_input_types);
                }
 
                template<typename FieldType, typename BlueprintType>
                snark::r1cs_variable_assignment<FieldType>
                    compliance_predicate_handler<FieldType, BlueprintType>::get_full_variable_assignment() const {
                    return bp.full_variable_assignment();
                }
 
                template<typename FieldType, typename BlueprintType>
                std::shared_ptr<r1cs_pcd_message<FieldType>>
                    compliance_predicate_handler<FieldType, BlueprintType>::get_outgoing_message() const {
                    return outgoing_message->get_message();
                }
 
                template<typename FieldType, typename BlueprintType>
                std::size_t compliance_predicate_handler<FieldType, BlueprintType>::get_arity() const {
                    return bp.val(arity).as_ulong();
                }
 
                template<typename FieldType, typename BlueprintType>
                std::shared_ptr<r1cs_pcd_message<FieldType>>
                    compliance_predicate_handler<FieldType, BlueprintType>::get_incoming_message(
                        const std::size_t message_idx) const {
                    assert(message_idx < max_arity);
                    return incoming_messages[message_idx]->get_message();
                }
 
                template<typename FieldType, typename BlueprintType>
                std::shared_ptr<r1cs_pcd_local_data<FieldType>>
                    compliance_predicate_handler<FieldType, BlueprintType>::get_local_data() const {
                    return local_data->get_local_data();
                }
 
                template<typename FieldType, typename BlueprintType>
                r1cs_pcd_witness<FieldType>
                    compliance_predicate_handler<FieldType, BlueprintType>::get_witness() const {
                    const snark::r1cs_variable_assignment<FieldType> va = bp.full_variable_assignment();
                    // outgoing_message + arity + incoming_messages + local_data
                    const std::size_t witness_pos =
                        (outgoing_message->all_vars.size() + 1 +
                         std::accumulate(
                             incoming_messages.begin(), incoming_messages.end(), 0,
                             [](std::size_t acc, const std::shared_ptr<r1cs_pcd_message_variable<FieldType>> &msg) {
                                 return acc + msg->all_vars.size();
                             }) +
                         local_data->all_vars.size());
 
                    return snark::r1cs_variable_assignment<FieldType>(va.begin() + witness_pos, va.end());
                }
            }    // namespace snark
        }        // namespace zk
    }            // namespace crypto3
}    // namespace nil
 
#endif    // CRYPTO3_ZK_BLUEPRINT_CP_HANDLER_HPP