refactor: optimize Vec push avoid realloc mem

.changelog/unreleased/improvements/1374-optimize-vec-push-avoid-realloc-mem.md

@@ -0,0 +1,2 @@
+- [ibc-app-nft-transfer] optimize `Vec` pushes to avoid reallocation of memory
+  ([\#1374](https://github.com/cosmos/ibc-rs/pull/1374)).

ibc-apps/ics721-nft-transfer/src/handler/on_recv_packet.rs

@@ -79,7 +79,7 @@
         };
 
         let mut extras = ModuleExtras {
-            events: vec![],
+            events: Vec::with_capacity(data.token_ids.0.len()),
             log: Vec::new(),
         };
         for (i, token_id) in data.token_ids.0.iter().enumerate() {

ibc-apps/ics721-nft-transfer/src/handler/send_transfer.rs

@@ -172,9 +172,11 @@
     // overwrite even if they are set in MsgTransfer
     if let Some(uris) = &mut packet_data.token_uris {
         uris.clear();
+        uris.reserve_exact(token_ids.0.len());
     }
     if let Some(data) = &mut packet_data.token_data {
         data.clear();
+        data.reserve_exact(token_ids.0.len());
     }
     for token_id in token_ids.as_ref() {
         if is_sender_chain_source(msg.port_id_on_a.clone(), msg.chan_id_on_a.clone(), class_id) {
@@ -197,14 +199,14 @@
         let nft = transfer_ctx.get_nft(class_id, token_id)?;
         // Set the URI and the data if both exists
         if let (Some(uri), Some(data)) = (nft.get_uri(), nft.get_data()) {
-            match &mut packet_data.token_uris {
-                Some(uris) => uris.push(uri.clone()),
-                None => packet_data.token_uris = Some(vec![uri.clone()]),
-            }
-            match &mut packet_data.token_data {
-                Some(token_data) => token_data.push(data.clone()),
-                None => packet_data.token_data = Some(vec![data.clone()]),
-            }
+            packet_data
+                .token_uris
+                .get_or_insert_with(|| Vec::with_capacity(token_ids.0.len()))
+                .push(uri.clone());
+            packet_data
+                .token_data
+                .get_or_insert_with(|| Vec::with_capacity(token_ids.0.len()))
+                .push(data.clone());
         }
     }
 

ibc-derive/src/client_state.rs

@@ -118,6 +118,7 @@ fn split_for_impl(
     let mut predicates = vec![];
 
     if let syn::PathArguments::AngleBracketed(gen) = args {
+        generics.reserve_exact(gen.args.len());
         for arg in gen.args {
             match arg.clone() {
                 GenericArgument::Type(_) | GenericArgument::Lifetime(_) => {