Merge pull request #20 from HyunggyuJang/refactor/without-external-ca…

…ll-pair-for Make pair_for method internal call
AstarNetwork · Oct 24, 2022 · af0bf97 · af0bf97
2 parents 0267ec8 + 577e066
commit af0bf97
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Showing 4 changed files with 18 additions and 7 deletions.
diff --git a/tests/router.ts b/tests/router.ts
@@ -20,7 +20,7 @@ describe('ROUTER', () => {
         const match = tokenA.contract.address.toString() == token0Address.output.toString()
         const token0 = match ? tokenA : tokenB
         const token1 = match ? tokenB : tokenA
-        const router_contract = await setupContract('router_contract', 'new', factory_contract.contract.address)
+        const router_contract = await setupContract('router_contract', 'new', factory_contract.contract.address, pair_code_hash)
 
         return {
             wallet,

diff --git a/uniswap-v2/contracts/router/lib.rs b/uniswap-v2/contracts/router/lib.rs
@@ -21,9 +21,10 @@ pub mod router {
 
     impl RouterContract {
         #[ink(constructor)]
-        pub fn new(factory: AccountId) -> Self {
+        pub fn new(factory: AccountId, pair_code_hash: Hash) -> Self {
             ink_lang::codegen::initialize_contract(|instance: &mut Self| {
                 instance.router.factory = factory;
+                instance.router.pair_code_hash = pair_code_hash;
             })
         }
     }

diff --git a/uniswap-v2/logics/impls/router/data.rs b/uniswap-v2/logics/impls/router/data.rs
@@ -1,3 +1,4 @@
+use ink_env::Hash;
 use openbrush::traits::AccountId;
 
 pub const STORAGE_KEY: u32 = openbrush::storage_unique_key!(Data);
@@ -6,4 +7,5 @@ pub const STORAGE_KEY: u32 = openbrush::storage_unique_key!(Data);
 #[openbrush::upgradeable_storage(STORAGE_KEY)]
 pub struct Data {
     pub factory: AccountId,
+    pub pair_code_hash: Hash,
 }
diff --git a/uniswap-v2/logics/impls/router/router.rs b/uniswap-v2/logics/impls/router/router.rs
@@ -9,6 +9,7 @@ pub use crate::{
         router::*,
     },
 };
+use ink_env::hash::Blake2x256;
 use ink_prelude::{
     vec,
     vec::Vec,
@@ -428,17 +429,24 @@ impl<T: Storage<data::Data>> Router for T {
     /// Original Uniswap Library pairFor function calculate pair contract address without making cross contract calls.
     /// Please refer /~https://github.com/Uniswap/v2-periphery/blob/master/contracts/libraries/UniswapV2Library.sol#L18
     ///
-    /// In this contract, use cross contract call to get pair contract address.
+    /// In this contract, use precomputed address like Uniswap's, as ink!'s deployment is done via create2-like one by default.
+    /// Please refer /~https://github.com/paritytech/substrate/blob/493b58bd4a475080d428ce47193ee9ea9757a808/frame/contracts/src/lib.rs#L178
+    /// for how contract's address is calculated.
     default fn _pair_for(
         &self,
         factory: AccountId,
         token_a: AccountId,
         token_b: AccountId,
     ) -> Result<AccountId, RouterError> {
-        let (token_0, token_1) = self._sort_tokens(token_a, token_b)?;
-        let pair =
-            FactoryRef::get_pair(&factory, token_0, token_1).ok_or(RouterError::PairNotFound)?;
-        Ok(pair)
+        let tokens = self._sort_tokens(token_a, token_b)?;
+        let salt = &Self::env().hash_encoded::<Blake2x256, _>(&tokens)[..4];
+        let input: Vec<_> = AsRef::<[u8]>::as_ref(&factory)
+            .iter()
+            .chain(self.data().pair_code_hash.as_ref())
+            .chain(salt)
+            .cloned()
+            .collect();
+        Ok(Self::env().hash_bytes::<Blake2x256>(&input).into())
     }
 
     default fn _sort_tokens(