darkfi_contract_test_harness/
money_otc_swap.rs

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1/* This file is part of DarkFi (https://dark.fi)
2 *
3 * Copyright (C) 2020-2025 Dyne.org foundation
4 *
5 * This program is free software: you can redistribute it and/or modify
6 * it under the terms of the GNU Affero General Public License as
7 * published by the Free Software Foundation, either version 3 of the
8 * License, or (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 * GNU Affero General Public License for more details.
14 *
15 * You should have received a copy of the GNU Affero General Public License
16 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
17 */
18
19use darkfi::{
20    tx::{ContractCallLeaf, Transaction, TransactionBuilder},
21    zk::halo2::Field,
22    Result,
23};
24use darkfi_money_contract::{
25    client::{swap_v1::SwapCallBuilder, MoneyNote, OwnCoin},
26    model::{MoneyFeeParamsV1, MoneyTransferParamsV1},
27    MoneyFunction, MONEY_CONTRACT_ZKAS_BURN_NS_V1, MONEY_CONTRACT_ZKAS_MINT_NS_V1,
28};
29use darkfi_sdk::{
30    crypto::{contract_id::MONEY_CONTRACT_ID, BaseBlind, Blind, FuncId, MerkleNode},
31    pasta::pallas,
32    ContractCall,
33};
34use darkfi_serial::AsyncEncodable;
35use log::debug;
36use rand::rngs::OsRng;
37
38use super::{Holder, TestHarness};
39
40impl TestHarness {
41    /// Create a `Money::OtcSwap` transaction with two given [`Holder`]s.
42    ///
43    /// Returns the [`Transaction`], and the transaction parameters.
44    pub async fn otc_swap(
45        &mut self,
46        holder0: &Holder,
47        owncoin0: &OwnCoin,
48        holder1: &Holder,
49        owncoin1: &OwnCoin,
50        block_height: u32,
51    ) -> Result<(Transaction, MoneyTransferParamsV1, Option<MoneyFeeParamsV1>)> {
52        let wallet0 = self.holders.get(holder0).unwrap();
53        let wallet1 = self.holders.get(holder1).unwrap();
54
55        let (mint_pk, mint_zkbin) = self.proving_keys.get(MONEY_CONTRACT_ZKAS_MINT_NS_V1).unwrap();
56        let (burn_pk, burn_zkbin) = self.proving_keys.get(MONEY_CONTRACT_ZKAS_BURN_NS_V1).unwrap();
57
58        // Use a zero spend_hook and user_data
59        let rcpt_spend_hook = FuncId::none();
60        let rcpt_user_data = pallas::Base::ZERO;
61        let rcpt_user_data_blind = Blind::random(&mut OsRng);
62
63        // Create blinding factors for commitments
64        let value_send_blind = Blind::random(&mut OsRng);
65        let value_recv_blind = Blind::random(&mut OsRng);
66        let token_send_blind = BaseBlind::random(&mut OsRng);
67        let token_recv_blind = BaseBlind::random(&mut OsRng);
68
69        // Build the first half of the swap for Holder0
70        let builder = SwapCallBuilder {
71            pubkey: wallet0.keypair.public,
72            value_send: owncoin0.note.value,
73            token_id_send: owncoin0.note.token_id,
74            value_recv: owncoin1.note.value,
75            token_id_recv: owncoin1.note.token_id,
76            user_data_blind_send: rcpt_user_data_blind,
77            spend_hook_recv: rcpt_spend_hook,
78            user_data_recv: rcpt_user_data,
79            value_blinds: [value_send_blind, value_recv_blind],
80            token_blinds: [token_send_blind, token_recv_blind],
81            coin: owncoin0.clone(),
82            tree: wallet0.money_merkle_tree.clone(),
83            mint_zkbin: mint_zkbin.clone(),
84            mint_pk: mint_pk.clone(),
85            burn_zkbin: burn_zkbin.clone(),
86            burn_pk: burn_pk.clone(),
87        };
88
89        let debris0 = builder.build()?;
90        assert!(debris0.params.inputs.len() == 1);
91        assert!(debris0.params.outputs.len() == 1);
92
93        // Build the second half of the swap for Holder1
94        let builder = SwapCallBuilder {
95            pubkey: wallet1.keypair.public,
96            value_send: owncoin1.note.value,
97            token_id_send: owncoin1.note.token_id,
98            value_recv: owncoin0.note.value,
99            token_id_recv: owncoin0.note.token_id,
100            user_data_blind_send: rcpt_user_data_blind,
101            spend_hook_recv: rcpt_spend_hook,
102            user_data_recv: rcpt_user_data,
103            value_blinds: [value_recv_blind, value_send_blind],
104            token_blinds: [token_recv_blind, token_send_blind],
105            coin: owncoin1.clone(),
106            tree: wallet1.money_merkle_tree.clone(),
107            mint_zkbin: mint_zkbin.clone(),
108            mint_pk: mint_pk.clone(),
109            burn_zkbin: burn_zkbin.clone(),
110            burn_pk: burn_pk.clone(),
111        };
112
113        let debris1 = builder.build()?;
114        assert!(debris1.params.inputs.len() == 1);
115        assert!(debris1.params.outputs.len() == 1);
116
117        // Holder1 then combines the halves
118        let swap_full_params = MoneyTransferParamsV1 {
119            inputs: vec![debris0.params.inputs[0].clone(), debris1.params.inputs[0].clone()],
120            outputs: vec![debris0.params.outputs[0].clone(), debris1.params.outputs[0].clone()],
121        };
122
123        let swap_full_proofs = vec![
124            debris0.proofs[0].clone(),
125            debris1.proofs[0].clone(),
126            debris0.proofs[1].clone(),
127            debris1.proofs[1].clone(),
128        ];
129
130        // Encode the contract call
131        let mut data = vec![MoneyFunction::OtcSwapV1 as u8];
132        swap_full_params.encode_async(&mut data).await?;
133        let call = ContractCall { contract_id: *MONEY_CONTRACT_ID, data };
134        let mut tx_builder =
135            TransactionBuilder::new(ContractCallLeaf { call, proofs: swap_full_proofs }, vec![])?;
136
137        // If we have tx fees enabled, make an offering
138        let mut fee_params = None;
139        let mut fee_signature_secrets = None;
140        if self.verify_fees {
141            let mut tx = tx_builder.build()?;
142            let sigs = tx.create_sigs(&[debris1.signature_secret])?;
143            tx.signatures = vec![sigs];
144
145            // First holder gets the partially signed transaction and adds their signature
146            let sigs = tx.create_sigs(&[debris0.signature_secret])?;
147            tx.signatures[0].insert(0, sigs[0]);
148
149            let (fee_call, fee_proofs, fee_secrets, _spent_fee_coins, fee_call_params) =
150                self.append_fee_call(holder0, tx, block_height, &[owncoin0.clone()]).await?;
151
152            // Append the fee call to the transaction
153            tx_builder.append(ContractCallLeaf { call: fee_call, proofs: fee_proofs }, vec![])?;
154            fee_signature_secrets = Some(fee_secrets);
155            fee_params = Some(fee_call_params);
156        }
157
158        // Now build the actual transaction and sign it with necessary keys.
159        let mut tx = tx_builder.build()?;
160        let sigs = tx.create_sigs(&[debris1.signature_secret])?;
161        tx.signatures = vec![sigs];
162        // First holder gets the partially signed transaction and adds their signature
163        let sigs = tx.create_sigs(&[debris0.signature_secret])?;
164        tx.signatures[0].insert(0, sigs[0]);
165
166        if let Some(fee_signature_secrets) = fee_signature_secrets {
167            let sigs = tx.create_sigs(&fee_signature_secrets)?;
168            tx.signatures.push(sigs);
169        }
170
171        Ok((tx, swap_full_params, fee_params))
172    }
173
174    /// Execute the transaction created by `otc_swap()` for a given [`Holder`].
175    ///
176    /// Returns any found [`OwnCoin`]s.
177    pub async fn execute_otc_swap_tx(
178        &mut self,
179        holder: &Holder,
180        tx: Transaction,
181        swap_params: &MoneyTransferParamsV1,
182        fee_params: &Option<MoneyFeeParamsV1>,
183        block_height: u32,
184        append: bool,
185    ) -> Result<Vec<OwnCoin>> {
186        let wallet = self.holders.get_mut(holder).unwrap();
187
188        // Execute the transaction
189        wallet.add_transaction("money::otc_swap", tx, block_height).await?;
190
191        let mut found_owncoins = vec![];
192
193        if !append {
194            return Ok(found_owncoins)
195        }
196
197        let mut inputs = swap_params.inputs.to_vec();
198        let mut outputs = swap_params.outputs.to_vec();
199        if let Some(ref fee_params) = fee_params {
200            inputs.push(fee_params.input.clone());
201            outputs.push(fee_params.output.clone());
202        }
203
204        let nullifiers = inputs.iter().map(|i| i.nullifier.inner()).map(|l| (l, l)).collect();
205        wallet.money_null_smt.insert_batch(nullifiers).expect("smt.insert_batch()");
206
207        for input in inputs {
208            if let Some(spent_coin) = wallet
209                .unspent_money_coins
210                .iter()
211                .find(|x| x.nullifier() == input.nullifier)
212                .cloned()
213            {
214                debug!("Found spent OwnCoin({}) for {:?}", spent_coin.coin, holder);
215                wallet.unspent_money_coins.retain(|x| x.nullifier() != input.nullifier);
216                wallet.spent_money_coins.push(spent_coin.clone());
217            }
218        }
219
220        for output in outputs {
221            wallet.money_merkle_tree.append(MerkleNode::from(output.coin.inner()));
222
223            // Attempt to decrypt the encrypted note
224            let Ok(note) = output.note.decrypt::<MoneyNote>(&wallet.keypair.secret) else {
225                continue
226            };
227
228            let owncoin = OwnCoin {
229                coin: output.coin,
230                note: note.clone(),
231                secret: wallet.keypair.secret,
232                leaf_position: wallet.money_merkle_tree.mark().unwrap(),
233            };
234
235            debug!("Found new OwnCoin({}) for {:?}", owncoin.coin, holder);
236            wallet.unspent_money_coins.push(owncoin.clone());
237            found_owncoins.push(owncoin);
238        }
239
240        Ok(found_owncoins)
241    }
242}
darkfi_contract_test_harness/money_otc_swap.rs

darkfi_contract_test_harness/
money_otc_swap.rs
