Some utility functions (#45)

pallet-ismp/src/handlers.rs

@@ -0,0 +1,82 @@
+//! Some extra utilities for pallet-ismp
+
+use crate::{
+    dispatcher::Receipt, host::Host, Config, Event, IncomingRequestAcks, IncomingResponseAcks,
+    Pallet,
+};
+use alloc::string::ToString;
+use ismp_primitives::mmr::Leaf;
+use ismp_rs::{
+    router::{DispatchError, DispatchResult, DispatchSuccess, Request, Response},
+    util::{hash_request, hash_response},
+};
+use sp_core::H256;
+
+impl<T: Config> Pallet<T>
+where
+    <T as frame_system::Config>::Hash: From<H256>,
+{
+    /// Handle an incoming request
+    pub fn handle_request(&self, request: Request) -> DispatchResult {
+        let commitment = hash_request::<Host<T>>(&request).0.to_vec();
+
+        if IncomingRequestAcks::<T>::contains_key(commitment.clone()) {
+            Err(DispatchError {
+                msg: "Duplicate request".to_string(),
+                nonce: request.nonce(),
+                source: request.source_chain(),
+                dest: request.dest_chain(),
+            })?
+        }
+
+        let (dest_chain, source_chain, nonce) =
+            (request.dest_chain(), request.source_chain(), request.nonce());
+        Pallet::<T>::mmr_push(Leaf::Request(request)).ok_or_else(|| DispatchError {
+            msg: "Failed to push request into mmr".to_string(),
+            nonce,
+            source: source_chain,
+            dest: dest_chain,
+        })?;
+        // Deposit Event
+        Pallet::<T>::deposit_event(Event::Request {
+            request_nonce: nonce,
+            source_chain,
+            dest_chain,
+        });
+
+        IncomingRequestAcks::<T>::insert(commitment, Receipt::Ok);
+        Ok(DispatchSuccess { dest_chain, source_chain, nonce })
+    }
+
+    /// Handle an incoming response
+    pub fn handle_response(&self, response: Response) -> DispatchResult {
+        let commitment = hash_response::<Host<T>>(&response).0.to_vec();
+
+        if IncomingResponseAcks::<T>::contains_key(commitment.clone()) {
+            Err(DispatchError {
+                msg: "Duplicate response".to_string(),
+                nonce: response.nonce(),
+                source: response.source_chain(),
+                dest: response.dest_chain(),
+            })?
+        }
+
+        let (dest_chain, source_chain, nonce) =
+            (response.dest_chain(), response.source_chain(), response.nonce());
+
+        Pallet::<T>::mmr_push(Leaf::Response(response)).ok_or_else(|| DispatchError {
+            msg: "Failed to push response into mmr".to_string(),
+            nonce,
+            source: source_chain,
+            dest: dest_chain,
+        })?;
+
+        Pallet::<T>::deposit_event(Event::Response {
+            request_nonce: nonce,
+            dest_chain,
+            source_chain,
+        });
+        IncomingResponseAcks::<T>::insert(commitment, Receipt::Ok);
+        Ok(DispatchSuccess { dest_chain, source_chain, nonce })
+    }
+}

pallet-ismp/src/lib.rs

@@ -25,6 +25,7 @@ pub mod benchmarking;
 pub mod dispatcher;
 mod errors;
 pub mod events;
+pub mod handlers;
 pub mod host;
 mod mmr;
 #[cfg(test)]
@@ -586,7 +587,7 @@ where
     }
 
     /// Insert a leaf into the mmr
-    pub fn mmr_push(leaf: Leaf) -> Option<NodeIndex> {
+    pub(crate) fn mmr_push(leaf: Leaf) -> Option<NodeIndex> {
         let offchain_key = match &leaf {
             Leaf::Request(req) => Pallet::<T>::request_leaf_index_offchain_key(
                 req.source_chain(),