Implement basic DEX Router pallet.

frame/composable-traits/src/dex.rs

@@ -2,6 +2,7 @@ use codec::{Decode, Encode};
 use scale_info::TypeInfo;
 use sp_runtime::{DispatchError, FixedU128, Permill};
 use sp_std::vec::Vec;
+use frame_support::RuntimeDebug;
 
 /// Implement AMM curve from "StableSwap - efficient mechanism for Stablecoin liquidity by Micheal
 /// Egorov" Also blog at https://miguelmota.com/blog/understanding-stableswap-curve/ has very good explanation.
@@ -66,7 +67,7 @@ pub trait CurveAmm {
 }
 
 /// Pool type
-#[derive(Encode, Decode, TypeInfo, Clone, Default, PartialEq, Eq, Debug)]
+#[derive(Encode, Decode, TypeInfo, Clone, Default, PartialEq, Eq, RuntimeDebug)]
 pub struct StableSwapPoolInfo<AccountId> {
 	/// Owner of pool
 	pub owner: AccountId,
@@ -100,10 +101,25 @@ pub trait SimpleExchange {
 	) -> Result<Self::Balance, DispatchError>;
 }
 
-#[derive(Encode, Decode, TypeInfo, Clone, Default, PartialEq, Eq, Debug)]
+#[derive(Encode, Decode, TypeInfo, Clone, Default, PartialEq, Eq, RuntimeDebug)]
 pub struct ConstantProductPoolInfo<AccountId> {
 	/// Owner of pool
 	pub owner: AccountId,
 	/// Amount of the fee pool charges for the exchange
 	pub fee: Permill,
 }
+
+/// Describes route for DEX, Direct gives pool_id to use,
+/// Via gives recursive route with pair of pool_id, route_id.
+#[derive(Encode, Decode, TypeInfo, Clone, PartialEq, Eq, RuntimeDebug)]
+pub enum DexRoute<PoolId, RouteId> {
+    Direct(PoolId),
+    Via((PoolId, RouteId))
+}
+
+pub trait DexRouter<AssetId, PoolId, RouteId> {
+    /// if route is `None` then delete existing entry for `asset_pair`
+    /// if route is `Some` and no entry exist for `asset_pair` then add new entry else update
+    /// existing entry.
+    fn update(asset_pair : (AssetId, AssetId), route : Option<DexRoute<PoolId, RouteId>>);
+}

frame/dex-router/Cargo.toml

@@ -0,0 +1,43 @@
+[package]
+name = "pallet-dex-router"
+version = "0.0.1"
+authors = ["Composable Developers"]
+homepage = "https://composable.finance"
+edition = "2021"
+rust-version = "1.56"
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[dependencies]
+frame-support = { default-features = false, git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.13"  }
+frame-system = { default-features = false,  git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.13" }
+
+sp-runtime = { default-features = false,  git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.13" }
+sp-arithmetic = { default-features = false,  git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.13" }
+sp-io = {  default-features = false,  git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.13" }
+sp-core = {  default-features = false,  git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.13" }
+sp-std = {  default-features = false,  git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.13" }
+
+composable-traits = { path = "../composable-traits", default-features = false }
+orml-traits = { git = "https://github.com/open-web3-stack/open-runtime-module-library", rev = "17a791edf431d7d7aee1ea3dfaeeb7bc21944301", default-features = false }
+scale-info = { version = "1.0", default-features = false, features = ["derive"] }
+
+[dependencies.codec]
+default-features = false
+features = ["derive"]
+package = "parity-scale-codec"
+version = "2.0.0"
+
+[dev-dependencies]
+pallet-balances = { git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.13" }
+
+[features]
+default = ["std"]
+std = [
+    "codec/std",
+    "frame-support/std",
+    "frame-system/std",
+    "sp-runtime/std",
+    "orml-traits/std",
+]

frame/dex-router/src/lib.rs

@@ -0,0 +1,105 @@
+//! # DEX Router Pallet
+//!
+//! Is used to add route to DEX for given asset_id's pair.
+
+#![cfg_attr(not(test), warn(clippy::disallowed_method, clippy::indexing_slicing))] // allow in tests
+#![warn(clippy::unseparated_literal_suffix, clippy::disallowed_type)]
+#![cfg_attr(not(feature = "std"), no_std)]
+
+pub use pallet::*;
+
+#[cfg(test)]
+mod mock;
+
+#[cfg(test)]
+mod tests;
+
+#[frame_support::pallet]
+pub mod pallet {
+	use codec::FullCodec;
+use composable_traits::{
+		currency::AssetIdLike,
+	    dex::{DexRoute, DexRouter},
+	};
+	use frame_support::pallet_prelude::*;
+
+
+	#[pallet::config]
+	pub trait Config: frame_system::Config {
+		type Event: From<Event<Self>> + IsType<<Self as frame_system::Config>::Event>;
+		type AssetId: AssetIdLike + Decode + Clone + core::fmt::Debug + Default;
+        type RouteId: FullCodec + Copy + Eq + PartialEq + core::fmt::Debug + TypeInfo;
+        type PoolId: FullCodec + Copy + Eq + PartialEq + core::fmt::Debug + TypeInfo;
+	}
+
+	#[pallet::pallet]
+	#[pallet::generate_store(trait Store)]
+	pub struct Pallet<T>(_);
+
+	#[pallet::storage]
+    pub type DexRoutes<T: Config> = StorageDoubleMap<
+        _,
+        Blake2_128Concat,
+        T::AssetId,
+        Blake2_128Concat,
+        T::AssetId,
+        DexRoute<T::PoolId, T::RouteId>,
+        OptionQuery,
+    >;
+
+	#[pallet::error]
+	pub enum Error<T> {
+	}
+
+	#[pallet::event]
+	#[pallet::generate_deposit(pub(super) fn deposit_event)]
+	pub enum Event<T: Config> {
+        RouteAdded { x_asset_id: T::AssetId, y_asset_id: T::AssetId, route : DexRoute<T::PoolId, T::RouteId> },
+        RouteDeleted { x_asset_id: T::AssetId, y_asset_id: T::AssetId, route : DexRoute<T::PoolId, T::RouteId> },
+        RouteUpdated { x_asset_id: T::AssetId, y_asset_id: T::AssetId, route : DexRoute<T::PoolId, T::RouteId> },
+	}
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {
+	}
+
+	impl<T: Config> Pallet<T> {
+	}
+
+    impl<T: Config> DexRouter<T::AssetId, T::PoolId, T::RouteId> for Pallet<T> {
+        fn update(asset_pair : (T::AssetId, T::AssetId), route : Option<DexRoute<T::PoolId, T::RouteId>>) {
+            match route {
+                Some(r) => {
+                    let mut update = false;
+                    if DexRoutes::<T>::contains_key(asset_pair.0, asset_pair.1) {
+                       update = true; 
+                    }
+                    DexRoutes::<T>::insert(asset_pair.0, asset_pair.1, r.clone());
+                    if update {
+                        Self::deposit_event(Event::RouteUpdated {
+                            x_asset_id : asset_pair.0,
+                            y_asset_id : asset_pair.1,
+                            route: r,
+                        });
+                    } else {
+                        Self::deposit_event(Event::RouteAdded {
+                            x_asset_id : asset_pair.0,
+                            y_asset_id : asset_pair.1,
+                            route: r,
+                        });
+                    }
+                },
+                None => {
+                    if DexRoutes::<T>::contains_key(asset_pair.0, asset_pair.1) {
+                        let r = DexRoutes::<T>::take(asset_pair.0, asset_pair.1).expect("inconsistent storage");
+                        Self::deposit_event(Event::RouteDeleted {
+                            x_asset_id : asset_pair.0,
+                            y_asset_id : asset_pair.1,
+                            route: r,
+                        });
+                    }
+                }
+            }
+        }
+    }
+}