feat: Add post handler for cosmos transact (#89)

* feat: Add post handler for cosmos transact

* refactor: Refactor simulate cosmos tx api

* fix: Add default config for PostHandler

frame/cosmos/rpc/Cargo.toml

@@ -12,6 +12,7 @@ cosmos-runtime-api = { workspace = true, features = ["std"] }
 futures = "0.3"
 hex = "0.4.3"
 jsonrpsee = { version = "0.24", features = ["client", "server", "macros"] }
+pallet-cosmos-types = { workspace = true, features = ["std"] }
 sc-transaction-pool-api = { git = "https://github.com/paritytech/polkadot-sdk", branch = "stable2409" }
 sp-api = { git = "https://github.com/paritytech/polkadot-sdk", branch = "stable2409" }
 sp-blockchain = { git = "https://github.com/paritytech/polkadot-sdk", branch = "stable2409" }

frame/cosmos/rpc/src/cosmos.rs

@@ -16,12 +16,13 @@
 // limitations under the License.
 
 use crate::{internal_error, request_error};
-use cosmos_runtime_api::{ChainInfo, CosmosRuntimeApi, SimulateError, SimulateResponse};
+use cosmos_runtime_api::{ChainInfo, CosmosRuntimeApi, SimulateError};
 use futures::future::TryFutureExt;
 use jsonrpsee::{
 	core::{async_trait, RpcResult},
 	proc_macros::rpc,
 };
+use pallet_cosmos_types::tx::SimulateResponse;
 use sc_transaction_pool_api::TransactionPool;
 use sp_api::ProvideRuntimeApi;
 use sp_blockchain::HeaderBackend;

frame/cosmos/runtime-api/src/lib.rs

@@ -20,25 +20,13 @@
 extern crate alloc;
 
 use alloc::{string::String, vec::Vec};
-use pallet_cosmos_types::{events::CosmosEvent, gas::Gas};
+use pallet_cosmos_types::tx::SimulateResponse;
 use parity_scale_codec::{Decode, Encode};
 use scale_info::TypeInfo;
 use serde::{Deserialize, Serialize};
 use sp_api::decl_runtime_apis;
 use sp_runtime::traits::Block as BlockT;
 
-#[derive(Clone, Decode, Encode, Debug, TypeInfo, Serialize, Deserialize)]
-pub struct GasInfo {
-	pub gas_wanted: Gas,
-	pub gas_used: Gas,
-}
-
-#[derive(Clone, Decode, Encode, Debug, TypeInfo, Serialize, Deserialize)]
-pub struct SimulateResponse {
-	pub gas_info: GasInfo,
-	pub events: Vec<CosmosEvent>,
-}
-
 #[derive(Clone, Decode, Encode, Debug, Eq, PartialEq, TypeInfo)]
 pub enum SimulateError {
 	InvalidTx,

frame/cosmos/src/lib.rs

@@ -37,8 +37,9 @@ use pallet_cosmos_types::{
 	errors::{CosmosError, RootError},
 	events::traits::EventManager,
 	gas::traits::GasMeter,
-	handler::AnteDecorator,
+	handler::{AnteDecorator, PostDecorator},
 	msgservice::traits::MsgServiceRouter,
+	tx::{GasInfo, SimulateResponse},
 	tx_msgs::FeeTx,
 };
 use pallet_cosmos_x_auth_signing::sign_verifiable_tx::traits::SigVerifiableTx;
@@ -150,6 +151,7 @@ pub mod pallet {
 	use np_cosmos::traits::ChainInfo;
 	use pallet_cosmos_types::{
 		context::traits::MinGasPrices, errors::CosmosError, events::CosmosEvent, gas::Gas,
+		handler::PostDecorator,
 	};
 	use pallet_cosmos_x_auth_signing::sign_mode_handler::traits::SignModeHandler;
 	use sp_runtime::traits::{Convert, TryConvert};
@@ -165,6 +167,7 @@ pub mod pallet {
 	pub enum Event {
 		AnteHandled(Vec<CosmosEvent>),
 		Executed { gas_wanted: u64, gas_used: u64, events: Vec<CosmosEvent> },
+		PostHandled(Vec<CosmosEvent>),
 	}
 
 	#[pallet::error]
@@ -224,6 +227,9 @@ pub mod pallet {
 		/// Ante handler for fee and auth.
 		type AnteHandler: AnteDecorator;
 
+		/// Post handler to perform custom post-processing.
+		type PostHandler: PostDecorator<Self::Context>;
+
 		/// Message filter for allowed messages.
 		type MsgFilter: Contains<Any>;
 
@@ -295,6 +301,7 @@ pub mod pallet {
 			type WeightToGas = WeightToGas;
 			type Context = Context;
 			type AnteHandler = ();
+			type PostHandler = ();
 			type MaxMemoCharacters = MaxMemoCharacters;
 			type TxSigLimit = TxSigLimit;
 			type MaxDenomLimit = MaxDenomLimit;
@@ -379,7 +386,10 @@ impl<T: Config> Pallet<T> {
 				.with_weight(T::WeightToGas::convert(ctx.gas_meter().consumed_gas()))
 		})?;
 
-		// TODO: Implement PostHandlers for refund functionality
+		T::PostHandler::post_handle(&mut ctx, &tx, false).map_err(|e| {
+			Error::<T>::CosmosError(e)
+				.with_weight(T::WeightToGas::convert(ctx.gas_meter().consumed_gas()))
+		})?;
 
 		Self::deposit_event(Event::Executed {
 			gas_wanted: gas_limit,
@@ -408,4 +418,20 @@ impl<T: Config> Pallet<T> {
 
 		Ok(())
 	}
+
+	pub fn simulate(tx_bytes: Vec<u8>) -> Result<SimulateResponse, CosmosError> {
+		let tx = Tx::decode(&mut &*tx_bytes).map_err(|_| RootError::TxDecodeError)?;
+
+		T::AnteHandler::ante_handle(&tx, true)?;
+
+		let mut ctx = T::Context::new(T::SimulationGasLimit::get());
+		Self::run_tx(&mut ctx, &tx)?;
+
+		T::PostHandler::post_handle(&mut ctx, &tx, true)?;
+
+		Ok(SimulateResponse {
+			gas_info: GasInfo { gas_wanted: 0, gas_used: ctx.gas_meter().consumed_gas() },
+			events: ctx.event_manager().events(),
+		})
+	}
 }

frame/cosmos/types/src/handler.rs

@@ -15,7 +15,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use crate::errors::CosmosError;
+use crate::{context::traits::Context, errors::CosmosError};
 use cosmos_sdk_proto::cosmos::tx::v1beta1::Tx;
 
 pub trait AnteDecorator {
@@ -35,3 +35,21 @@ impl AnteDecorator for Tuple {
 		Ok(())
 	}
 }
+
+pub trait PostDecorator<C: Context> {
+	fn post_handle(ctx: &mut C, tx: &Tx, simulate: bool) -> Result<(), CosmosError>;
+}
+
+impl<C: Context> PostDecorator<C> for () {
+	fn post_handle(_ctx: &mut C, _tx: &Tx, _simulate: bool) -> Result<(), CosmosError> {
+		Ok(())
+	}
+}
+
+#[impl_trait_for_tuples::impl_for_tuples(1, 12)]
+impl<C: Context> PostDecorator<C> for Tuple {
+	fn post_handle(ctx: &mut C, tx: &Tx, simulate: bool) -> Result<(), CosmosError> {
+		for_tuples!( #( Tuple::post_handle(ctx, tx, simulate)?; )* );
+		Ok(())
+	}
+}

frame/cosmos/types/src/lib.rs

@@ -28,4 +28,5 @@ pub mod gas;
 pub mod handler;
 pub mod macros;
 pub mod msgservice;
+pub mod tx;
 pub mod tx_msgs;

frame/cosmos/types/src/tx.rs

@@ -0,0 +1,33 @@
+// This file is part of Noir.
+
+// Copyright (c) Haderech Pte. Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use crate::{events::CosmosEvent, gas::Gas};
+use parity_scale_codec::{Decode, Encode};
+use scale_info::TypeInfo;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Decode, Encode, Debug, TypeInfo, Serialize, Deserialize)]
+pub struct GasInfo {
+	pub gas_wanted: Gas,
+	pub gas_used: Gas,
+}
+
+#[derive(Clone, Decode, Encode, Debug, TypeInfo, Serialize, Deserialize)]
+pub struct SimulateResponse {
+	pub gas_info: GasInfo,
+	pub events: Vec<CosmosEvent>,
+}