feat: add wal_exchange contract (#168)

contracts/wal_exchange/Move.lock

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+# @generated by Move, please check-in and do not edit manually.
+
+[move]
+version = 3
+manifest_digest = "9BD464E4CF5DFF7B2A2445FBF02BC36F60218BD4A5262900323FCD6183B30723"
+deps_digest = "3C4103934B1E040BB6B23F1D610B4EF9F2F1166A50A104EADCF77467C004C600"
+dependencies = [
+  { id = "Sui", name = "Sui" },
+  { id = "WAL", name = "WAL" },
+]
+
+[[move.package]]
+id = "MoveStdlib"
+source = { git = "https://github.com/MystenLabs/sui.git", rev = "testnet-v1.35.0", subdir = "crates/sui-framework/packages/move-stdlib" }
+
+[[move.package]]
+id = "Sui"
+source = { git = "https://github.com/MystenLabs/sui.git", rev = "testnet-v1.35.0", subdir = "crates/sui-framework/packages/sui-framework" }
+
+dependencies = [
+  { id = "MoveStdlib", name = "MoveStdlib" },
+]
+
+[[move.package]]
+id = "WAL"
+source = { local = "../wal" }
+
+dependencies = [
+  { id = "Sui", name = "Sui" },
+]
+
+[move.toolchain-version]
+compiler-version = "1.35.0"
+edition = "2024.beta"
+flavor = "sui"
+
+
+[env]
+
+[env.testnet]
+chain-id = "4c78adac"
+original-published-id = "0x9f992cc2430a1f442ca7a5ca7638169f5d5c00e0ebc3977a65e9ac6e497fe5ef"
+latest-published-id = "0x9f992cc2430a1f442ca7a5ca7638169f5d5c00e0ebc3977a65e9ac6e497fe5ef"
+published-version = "1"

contracts/wal_exchange/Move.toml

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+[package]
+name = "WAL_exchange"
+license = "Apache-2.0"
+authors = ["Mysten Labs <[email protected]>"]
+edition = "2024.beta"
+
+[dependencies]
+Sui = { git = "https://github.com/MystenLabs/sui.git", subdir = "crates/sui-framework/packages/sui-framework", rev = "testnet-v1.35.0" }
+WAL = { local = "../wal" }
+
+[addresses]
+wal_exchange = "0x0"

contracts/wal_exchange/sources/wal_exchange.move

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+// Copyright (c) Mysten Labs, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+/// Module: wal_exchange
+module wal_exchange::wal_exchange;
+
+use sui::{balance::{Self, Balance}, coin::Coin, sui::SUI};
+use wal::wal::WAL;
+
+// Keep errors in `walrus-sui/types/move_errors.rs` up to date with changes here.
+const EInsufficientFundsInExchange: u64 = 0;
+const EInsufficientInputBalance: u64 = 1;
+const EUnauthorizedAdminCap: u64 = 2;
+const EInvalidExchangeRate: u64 = 3;
+
+/// A public exchange that allows exchanging SUI for WAL at a fixed exchange rate.
+public struct Exchange has key, store {
+    id: UID,
+    wal: Balance<WAL>,
+    sui: Balance<SUI>,
+    rate: ExchangeRate,
+    admin: ID,
+}
+
+/// Capability that allows the holder to modify an `Exchange`'s exchange rate and withdraw funds.
+public struct AdminCap has key, store {
+    id: UID,
+}
+
+/// Represents an exchange rate: `wal` WAL = `sui` SUI.
+public struct ExchangeRate has copy, drop, store {
+    wal: u64,
+    sui: u64,
+}
+
+// === Functions for `ExchangeRate` ===
+
+/// Creates a new exchange rate, making sure it is valid.
+public fun new_exchange_rate(wal: u64, sui: u64): ExchangeRate {
+    assert!(wal != 0 && sui != 0, EInvalidExchangeRate);
+    ExchangeRate { wal, sui }
+}
+
+fun wal_to_sui(self: &ExchangeRate, amount: u64): u64 {
+    amount * self.sui / self.wal
+}
+
+fun sui_to_wal(self: &ExchangeRate, amount: u64): u64 {
+    amount * self.wal / self.sui
+}
+
+// === Functions for `Exchange` ===
+
+// Creation functions
+
+/// Creates a new shared exchange with a 1:1 exchange rate and returns the associated `AdminCap`.
+public fun new(ctx: &mut TxContext): AdminCap {
+    let admin_cap = AdminCap {
+        id: object::new(ctx),
+    };
+    transfer::share_object(Exchange {
+        id: object::new(ctx),
+        wal: balance::zero(),
+        sui: balance::zero(),
+        rate: ExchangeRate { wal: 1, sui: 1 },
+        admin: object::id(&admin_cap),
+    });
+    admin_cap
+}
+
+/// Creates a new shared exchange with a 1:1 exchange rate, funds it with WAL, and returns the
+/// associated `AdminCap`.
+public fun new_funded(wal: &mut Coin<WAL>, amount: u64, ctx: &mut TxContext): AdminCap {
+    let admin_cap = AdminCap {
+        id: object::new(ctx),
+    };
+    let mut exchange = Exchange {
+        id: object::new(ctx),
+        wal: balance::zero(),
+        sui: balance::zero(),
+        rate: ExchangeRate { wal: 1, sui: 1 },
+        admin: object::id(&admin_cap),
+    };
+    exchange.add_wal(wal, amount);
+
+    transfer::share_object(exchange);
+    admin_cap
+}
+
+/// Adds WAL to the balance stored in the exchange.
+public fun add_wal(self: &mut Exchange, wal: &mut Coin<WAL>, amount: u64) {
+    self.wal.join(wal.balance_mut().split(amount));
+}
+
+/// Adds SUI to the balance stored in the exchange.
+public fun add_sui(self: &mut Exchange, sui: &mut Coin<SUI>, amount: u64) {
+    self.sui.join(sui.balance_mut().split(amount));
+}
+
+/// Adds WAL to the balance stored in the exchange.
+public fun add_all_wal(self: &mut Exchange, wal: Coin<WAL>) {
+    self.wal.join(wal.into_balance());
+}
+
+/// Adds SUI to the balance stored in the exchange.
+public fun add_all_sui(self: &mut Exchange, sui: Coin<SUI>) {
+    self.sui.join(sui.into_balance());
+}
+
+// Admin functions
+
+fun check_admin(self: &Exchange, admin_cap: &AdminCap) {
+    assert!(self.admin == object::id(admin_cap), EUnauthorizedAdminCap);
+}
+
+/// Withdraws WAL from the balance stored in the exchange.
+public fun withdraw_wal(
+    self: &mut Exchange,
+    amount: u64,
+    admin_cap: &AdminCap,
+    ctx: &mut TxContext,
+): Coin<WAL> {
+    self.check_admin(admin_cap);
+    assert!(self.wal.value() >= amount, EInsufficientFundsInExchange);
+    self.wal.split(amount).into_coin(ctx)
+}
+
+/// Withdraws SUI from the balance stored in the exchange.
+public fun withdraw_sui(
+    self: &mut Exchange,
+    amount: u64,
+    admin_cap: &AdminCap,
+    ctx: &mut TxContext,
+): Coin<SUI> {
+    self.check_admin(admin_cap);
+    assert!(self.sui.value() >= amount, EInsufficientFundsInExchange);
+    self.sui.split(amount).into_coin(ctx)
+}
+
+/// Sets the exchange rate of the exchange to `wal` WAL = `sui` SUI.
+public fun set_exchange_rate(self: &mut Exchange, wal: u64, sui: u64, admin_cap: &AdminCap) {
+    self.check_admin(admin_cap);
+    self.rate = new_exchange_rate(wal, sui);
+}
+
+// User functions
+
+/// Exchanges the provided SUI coin for WAL at the exchange's rate.
+public fun exchange_all_for_wal(
+    self: &mut Exchange,
+    sui: Coin<SUI>,
+    ctx: &mut TxContext,
+): Coin<WAL> {
+    let value_wal = self.rate.sui_to_wal(sui.value());
+    assert!(self.wal.value() >= value_wal, EInsufficientFundsInExchange);
+    self.sui.join(sui.into_balance());
+    self.wal.split(value_wal).into_coin(ctx)
+}
+
+/// Exchanges `amount_sui` out of the provided SUI coin for WAL at the exchange's rate.
+public fun exchange_for_wal(
+    self: &mut Exchange,
+    sui: &mut Coin<SUI>,
+    amount_sui: u64,
+    ctx: &mut TxContext,
+): Coin<WAL> {
+    assert!(sui.value() >= amount_sui, EInsufficientInputBalance);
+    self.exchange_all_for_wal(sui.split(amount_sui, ctx), ctx)
+}
+
+/// Exchanges the provided WAL coin for SUI at the exchange's rate.
+public fun exchange_all_for_sui(
+    self: &mut Exchange,
+    wal: Coin<WAL>,
+    ctx: &mut TxContext,
+): Coin<SUI> {
+    let value_sui = self.rate.wal_to_sui(wal.value());
+    assert!(self.sui.value() >= value_sui, EInsufficientFundsInExchange);
+    self.wal.join(wal.into_balance());
+    self.sui.split(value_sui).into_coin(ctx)
+}
+
+/// Exchanges `amount_wal` out of the provided WAL coin for SUI at the exchange's rate.
+public fun exchange_for_sui(
+    self: &mut Exchange,
+    wal: &mut Coin<WAL>,
+    amount_wal: u64,
+    ctx: &mut TxContext,
+): Coin<SUI> {
+    assert!(wal.value() >= amount_wal, EInsufficientInputBalance);
+    self.exchange_all_for_sui(wal.split(amount_wal, ctx), ctx)
+}
+
+// === Tests ===
+
+#[test_only]
+use sui::coin;
+#[test_only]
+use sui::test_utils::destroy;
+
+#[test_only]
+fun new_for_testing(wal_per_sui: u64, ctx: &mut TxContext): (Exchange, AdminCap) {
+    let admin_cap = AdminCap {
+        id: object::new(ctx),
+    };
+    (
+        Exchange {
+            id: object::new(ctx),
+            wal: balance::zero(),
+            sui: balance::zero(),
+            rate: ExchangeRate { wal: wal_per_sui, sui: 1 },
+            admin: object::id(&admin_cap),
+        },
+        admin_cap,
+    )
+}
+
+#[test]
+fun test_standard_flow() {
+    let ctx = &mut tx_context::dummy();
+    let (mut exchange, admin_cap) = new_for_testing(1, ctx);
+
+    exchange.set_exchange_rate(4, 2, &admin_cap);
+    exchange.add_all_wal(coin::mint_for_testing(1_000_000, ctx));
+    exchange.add_all_sui(coin::mint_for_testing(1_000_000, ctx));
+
+    let mut wal_coin = exchange.exchange_all_for_wal(coin::mint_for_testing(42, ctx), ctx);
+    assert!(wal_coin.value() == 84);
+    assert!(exchange.sui.value() == 1_000_042);
+    assert!(exchange.wal.value() == 999_916);
+
+    let mut sui_coin = exchange.exchange_for_sui(&mut wal_coin, 9, ctx);
+    assert!(sui_coin.value() == 4);
+    assert!(wal_coin.value() == 75);
+
+    let wal_coin_2 = exchange.exchange_for_wal(&mut sui_coin, 2, ctx);
+    assert!(wal_coin_2.value() == 4);
+    assert!(sui_coin.value() == 2);
+
+    let withdraw_wal_coin = exchange.withdraw_wal(13, &admin_cap, ctx);
+    assert!(withdraw_wal_coin.value() == 13);
+
+    let withdraw_sui_coin = exchange.withdraw_sui(42, &admin_cap, ctx);
+    assert!(withdraw_sui_coin.value() == 42);
+
+    destroy(wal_coin);
+    destroy(wal_coin_2);
+    destroy(sui_coin);
+    destroy(withdraw_wal_coin);
+    destroy(withdraw_sui_coin);
+    destroy(exchange);
+    destroy(admin_cap);
+}
+
+#[test]
+#[expected_failure(abort_code = EInsufficientFundsInExchange)]
+fun test_insufficient_funds_in_exchange() {
+    let ctx = &mut tx_context::dummy();
+    let (mut exchange, _admin_cap) = new_for_testing(2, ctx);
+
+    exchange.add_all_sui(coin::mint_for_testing(1_000_000, ctx));
+    let wal_coin = exchange.exchange_all_for_wal(coin::mint_for_testing(1, ctx), ctx);
+
+    destroy(wal_coin);
+    destroy(exchange);
+    destroy(_admin_cap);
+}
+
+#[test]
+#[expected_failure(abort_code = EInsufficientInputBalance)]
+fun test_insufficient_coin() {
+    let ctx = &mut tx_context::dummy();
+    let (mut exchange, _admin_cap) = new_for_testing(2, ctx);
+
+    exchange.add_all_sui(coin::mint_for_testing(1_000_000, ctx));
+    let mut sui_coin = coin::mint_for_testing(1, ctx);
+    let wal_coin = exchange.exchange_for_wal(&mut sui_coin, 2, ctx);
+
+    destroy(sui_coin);
+    destroy(wal_coin);
+    destroy(exchange);
+    destroy(_admin_cap);
+}
+
+#[test]
+#[expected_failure(abort_code = EUnauthorizedAdminCap)]
+fun test_unauthorized() {
+    let ctx = &mut tx_context::dummy();
+    let (mut exchange_1, _admin_cap_1) = new_for_testing(2, ctx);
+    let (mut _exchange_2, admin_cap_2) = new_for_testing(2, ctx);
+
+    exchange_1.set_exchange_rate(1, 1, &admin_cap_2);
+
+    destroy(exchange_1);
+    destroy(_admin_cap_1);
+    destroy(_exchange_2);
+    destroy(admin_cap_2);
+}
+
+#[test]
+fun test_creation() {
+    let ctx = &mut tx_context::dummy();
+    let mut coin = coin::mint_for_testing(1_000_000, ctx);
+    let _admin_cap_1 = new(ctx);
+    let _admin_cap_2 = new_funded(&mut coin, 100, ctx);
+    (ctx);
+
+    destroy(coin);
+    destroy(_admin_cap_1);
+    destroy(_admin_cap_2);
+}