remove ModifyQuantity

Author: ma2bd

examples/matching-engine/src/contract.rs

@@ -13,7 +13,7 @@ use linera_sdk::{
 use matching_engine::{
     MatchingEngineAbi, Message, Operation, Order, OrderNature, Parameters, PendingOrderInfo, Price,
 };
-use state::{MatchingEngineState, ModifyQuantity, Transfer};
+use state::{MatchingEngineState, Transfer};
 
 pub struct MatchingEngineContract {
     state: MatchingEngineState,
@@ -76,7 +76,7 @@ impl Contract for MatchingEngineContract {
                     .await
                     .expect("Failed to read existing order IDs");
                 for order_id in order_ids {
-                    match self.state.modify_order(order_id, ModifyQuantity::All).await {
+                    match self.state.modify_order(order_id, Amount::ZERO).await {
                         Some(transfer) => self.send_to(transfer),
                         // Orders with amount zero may have been cleared in an earlier iteration.
                         None => continue,
@@ -290,7 +290,7 @@ impl MatchingEngineContract {
 
                 let transfer = self
                     .state
-                    .modify_order(order_id, ModifyQuantity::All)
+                    .modify_order(order_id, Amount::ZERO)
                     .await
                     .expect("Order is not present therefore cannot be cancelled");
                 self.send_to(transfer);
@@ -329,27 +329,11 @@ impl MatchingEngineContract {
                     .expect("Order should exist");
                 let sender_chain_id = key_book.account.chain_id;
 
-                // Get the current quantity and calculate the reduction
-                let current_quantity = self
-                    .state
-                    .get_order_quantity(&order_id)
-                    .await
-                    .expect("Order should have a current amount");
-
-                assert!(
-                    new_quantity <= current_quantity,
-                    "New quantity must be less than or equal to current quantity"
-                );
-
-                let reduce_quantity = current_quantity
-                    .try_sub(new_quantity)
-                    .expect("Subtraction should not fail after validation");
-
                 let transfer = self
                     .state
-                    .modify_order(order_id, ModifyQuantity::Partial(reduce_quantity))
+                    .modify_order(order_id, new_quantity)
                     .await
-                    .expect("Order is not present therefore cannot be cancelled");
+                    .expect("Failed to modify order");
                 self.send_to(transfer);
 
                 // Get the remaining quantity after modification

examples/matching-engine/src/state.rs

@@ -167,7 +167,7 @@ impl MatchingEngineState {
     pub async fn modify_order(
         &mut self,
         order_id: OrderId,
-        cancel_quantity: ModifyQuantity,
+        new_quantity: Amount,
     ) -> Option<Transfer> {
         let key_book = self
             .orders
@@ -178,7 +178,7 @@ impl MatchingEngineState {
             OrderNature::Bid => {
                 let view = self.bid_level(&key_book.price.to_bid()).await;
                 let (cancel_quantity, remove_order_id) =
-                    view.modify_order_level(order_id, cancel_quantity).await?;
+                    view.modify_order_level(order_id, new_quantity).await?;
                 if remove_order_id {
                     self.remove_order_id((key_book.account.owner, order_id))
                         .await;
@@ -195,7 +195,7 @@ impl MatchingEngineState {
             OrderNature::Ask => {
                 let view = self.ask_level(&key_book.price.to_ask()).await;
                 let (cancel_quantity, remove_order_id) =
-                    view.modify_order_level(order_id, cancel_quantity).await?;
+                    view.modify_order_level(order_id, new_quantity).await?;
                 if remove_order_id {
                     self.remove_order_id((key_book.account.owner, order_id))
                         .await;
@@ -426,15 +426,6 @@ pub struct Transfer {
     pub token_idx: u32,
 }
 
-/// An order can be cancelled which removes it totally or
-/// modified which is a partial cancellation. The size of the
-/// order can never increase.
-#[derive(Clone, Debug)]
-pub enum ModifyQuantity {
-    All,
-    Partial(Amount),
-}
-
 impl LevelView {
     fn parameters(&self) -> Parameters {
         *self.context().extra()
@@ -609,24 +600,20 @@ impl LevelView {
     pub async fn modify_order_level(
         &mut self,
         order_id: OrderId,
-        reduce_quantity: ModifyQuantity,
+        new_quantity: Amount,
     ) -> Option<(Amount, bool)> {
         let mut iter = self
             .queue
             .iter_mut()
             .await
             .expect("Failed to load iterator over level queue");
         let state_order = iter.find(|order| order.order_id == order_id)?;
-        let new_quantity = match reduce_quantity {
-            ModifyQuantity::All => Amount::ZERO,
-            ModifyQuantity::Partial(reduce_quantity) => state_order
-                .quantity
-                .try_sub(reduce_quantity)
-                .expect("Attempt to cancel a larger quantity than available"),
-        };
-        let corr_reduce_quantity = state_order.quantity.try_sub(new_quantity).unwrap();
+        let cancel_quantity = state_order
+            .quantity
+            .try_sub(new_quantity)
+            .expect("Attempt to increase quantity");
         state_order.quantity = new_quantity;
         self.remove_zero_orders_from_level().await;
-        Some((corr_reduce_quantity, new_quantity == Amount::ZERO))
+        Some((cancel_quantity, new_quantity == Amount::ZERO))
     }
 }