solana: add executor to reserve fast fill (#172)

Co-authored-by: A5 Pickle <[email protected]>

Author: a5-pickle

solana/programs/matching-engine/src/processor/auction/execute_fast_order/local.rs

@@ -41,14 +41,15 @@ pub struct ExecuteFastOrderLocal<'info> {
     reserved_sequence: Account<'info, ReservedFastFillSequence>,
 
     /// When the reserved sequence account was created, the beneficiary was set to the best offer
-    /// token's owner. This account will receive the lamports from the reserved sequence account.
+    /// token's owner if it existed (and if not, to whomever executed the reserve fast fill sequence
+    /// instruction). This account will receive the lamports from the reserved sequence account.
     ///
     /// CHECK: This account's address must equal the one encoded in the reserved sequence account.
     #[account(
         mut,
         address = reserved_sequence.beneficiary,
     )]
-    best_offer_participant: UncheckedAccount<'info>,
+    reserve_beneficiary: UncheckedAccount<'info>,
 
     #[account(
         init,
@@ -150,5 +151,5 @@ pub fn execute_fast_order_local(ctx: Context<ExecuteFastOrderLocal>) -> Result<(
     // participant.
     ctx.accounts
         .reserved_sequence
-        .close(ctx.accounts.best_offer_participant.to_account_info())
+        .close(ctx.accounts.reserve_beneficiary.to_account_info())
 }

solana/programs/matching-engine/src/processor/fast_fill/reserve_sequence/active_auction.rs

@@ -63,6 +63,9 @@ pub struct ReserveFastFillSequenceActiveAuction<'info> {
 
     /// Best offer token account, whose owner will be the beneficiary of the reserved fast fill
     /// sequence account when it is closed.
+    ///
+    /// CHECK: This account may not exist. If it does, it should equal the best offer token pubkey
+    /// in the auction account.
     #[account(
         constraint = {
             // We know from the auction constraint that the auction is active, so the auction info
@@ -81,16 +84,36 @@ pub struct ReserveFastFillSequenceActiveAuction<'info> {
             true
         }
     )]
-    best_offer_token: Account<'info, token::TokenAccount>,
+    best_offer_token: UncheckedAccount<'info>,
+
+    /// CHECK: If the best offer token does not exist anymore, this executor will be the beneficiary
+    /// of the reserved fast fill sequence account when it is closed. Otherwise, this account must
+    /// equal the best offer token account's owner.
+    executor: UncheckedAccount<'info>,
 }
 
 pub fn reserve_fast_fill_sequence_active_auction(
     ctx: Context<ReserveFastFillSequenceActiveAuction>,
 ) -> Result<()> {
+    let best_offer_token = &ctx.accounts.best_offer_token;
+    let beneficiary = ctx.accounts.executor.key();
+
+    // If the token account does exist, we will constrain that the executor is the best offer token.
+    if let Ok(token) =
+        token::TokenAccount::try_deserialize(&mut &best_offer_token.data.borrow()[..])
+    {
+        require_keys_eq!(
+            *best_offer_token.owner,
+            token::ID,
+            ErrorCode::ConstraintTokenTokenProgram
+        );
+        require_keys_eq!(token.owner, beneficiary, ErrorCode::ConstraintTokenOwner);
+    }
+
     super::set_reserved_sequence_data(
         &mut ctx.accounts.reserve_sequence,
         &ctx.bumps.reserve_sequence,
         ctx.accounts.auction.vaa_hash,
-        ctx.accounts.best_offer_token.owner,
+        beneficiary,
     )
 }

solana/ts/src/idl/json/matching_engine.json

@@ -904,10 +904,11 @@
           "writable": true
         },
         {
-          "name": "best_offer_participant",
+          "name": "reserve_beneficiary",
           "docs": [
             "When the reserved sequence account was created, the beneficiary was set to the best offer",
-            "token's owner. This account will receive the lamports from the reserved sequence account.",
+            "token's owner if it existed (and if not, to whomever executed the reserve fast fill sequence",
+            "instruction). This account will receive the lamports from the reserved sequence account.",
             ""
           ],
           "writable": true
@@ -1646,7 +1647,16 @@
           "name": "best_offer_token",
           "docs": [
             "Best offer token account, whose owner will be the beneficiary of the reserved fast fill",
-            "sequence account when it is closed."
+            "sequence account when it is closed.",
+            "",
+            "in the auction account."
+          ]
+        },
+        {
+          "name": "executor",
+          "docs": [
+            "of the reserved fast fill sequence account when it is closed. Otherwise, this account must",
+            "equal the best offer token account's owner."
           ]
         }
       ],

solana/ts/src/idl/ts/matching_engine.ts

@@ -910,10 +910,11 @@ export type MatchingEngine = {
           "writable": true
         },
         {
-          "name": "bestOfferParticipant",
+          "name": "reserveBeneficiary",
           "docs": [
             "When the reserved sequence account was created, the beneficiary was set to the best offer",
-            "token's owner. This account will receive the lamports from the reserved sequence account.",
+            "token's owner if it existed (and if not, to whomever executed the reserve fast fill sequence",
+            "instruction). This account will receive the lamports from the reserved sequence account.",
             ""
           ],
           "writable": true
@@ -1652,7 +1653,16 @@ export type MatchingEngine = {
           "name": "bestOfferToken",
           "docs": [
             "Best offer token account, whose owner will be the beneficiary of the reserved fast fill",
-            "sequence account when it is closed."
+            "sequence account when it is closed.",
+            "",
+            "in the auction account."
+          ]
+        },
+        {
+          "name": "executor",
+          "docs": [
+            "of the reserved fast fill sequence account when it is closed. Otherwise, this account must",
+            "equal the best offer token account's owner."
           ]
         }
       ],

solana/ts/src/matchingEngine/index.ts

@@ -1789,7 +1789,7 @@ export class MatchingEngineProgram {
             sourceChain ??= fastVaaAccount.emitterInfo().chain;
 
             const message = LiquidityLayerMessage.decode(fastVaaAccount.payload());
-            if (message.fastMarketOrder == undefined) {
+            if (message.fastMarketOrder === undefined) {
                 throw new Error("Message not FastMarketOrder");
             }
 
@@ -2135,6 +2135,7 @@ export class MatchingEngineProgram {
             auction?: PublicKey;
             auctionConfig?: PublicKey;
             bestOfferToken?: PublicKey;
+            executor?: PublicKey;
         },
         opts: ReserveFastFillSequenceCompositeOpts = {},
     ): Promise<TransactionInstruction> {
@@ -2153,7 +2154,7 @@ export class MatchingEngineProgram {
         );
         const { fastVaaHash } = definedOpts;
 
-        let { auctionConfig, auction, bestOfferToken } = accounts;
+        let { auctionConfig, auction, bestOfferToken, executor } = accounts;
         auction ??= this.auctionAddress(fastVaaHash);
 
         if (bestOfferToken === undefined || auctionConfig === undefined) {
@@ -2165,13 +2166,24 @@ export class MatchingEngineProgram {
             bestOfferToken ??= info.bestOfferToken;
         }
 
+        if (executor === undefined) {
+            const token = await splToken
+                .getAccount(this.program.provider.connection, bestOfferToken)
+                .catch((_) => null);
+            if (token === null) {
+                throw new Error("Executor must be provided because best offer token is not found");
+            }
+            executor = token.owner;
+        }
+
         return this.program.methods
             .reserveFastFillSequenceActiveAuction()
             .accounts({
                 reserveSequence,
                 auction,
                 auctionConfig,
                 bestOfferToken,
+                executor,
             })
             .instruction();
     }
@@ -2229,7 +2241,7 @@ export class MatchingEngineProgram {
             bestOfferToken?: PublicKey;
             initialOfferToken?: PublicKey;
             initialParticipant?: PublicKey;
-            bestOfferParticipant?: PublicKey;
+            reserveBeneficiary?: PublicKey;
         },
         opts: {
             sourceChain?: ChainId;
@@ -2247,7 +2259,7 @@ export class MatchingEngineProgram {
             executorToken,
             initialOfferToken,
             initialParticipant,
-            bestOfferParticipant,
+            reserveBeneficiary,
         } = accounts;
         let { sourceChain, orderSender, sequence } = opts;
         executorToken ??= splToken.getAssociatedTokenAddressSync(this.mint, payer);
@@ -2271,11 +2283,12 @@ export class MatchingEngineProgram {
             orderSender ??= Array.from(fastMarketOrder.sender.toUint8Array());
         }
 
-        if (sequence === undefined) {
-            const { fastFillSeeds } = await this.fetchReservedFastFillSequence({
+        if (sequence === undefined || reserveBeneficiary === undefined) {
+            const reservedData = await this.fetchReservedFastFillSequence({
                 address: reservedSequence,
             });
-            sequence = fastFillSeeds.sequence;
+            sequence ??= reservedData.fastFillSeeds.sequence;
+            reserveBeneficiary ??= reservedData.beneficiary;
         }
 
         let auctionInfo: AuctionInfo | undefined;
@@ -2302,11 +2315,6 @@ export class MatchingEngineProgram {
             { auctionInfo },
         );
 
-        if (bestOfferParticipant === undefined) {
-            const token = await splToken.getAccount(connection, activeAuction.bestOfferToken);
-            bestOfferParticipant = token.owner;
-        }
-
         return this.program.methods
             .executeFastOrderLocal()
             .accounts({
@@ -2320,7 +2328,7 @@ export class MatchingEngineProgram {
                     initialParticipant,
                 },
                 reservedSequence,
-                bestOfferParticipant,
+                reserveBeneficiary,
                 fastFill: this.fastFillAddress(sourceChain, orderSender, sequence),
                 eventAuthority: this.eventAuthorityAddress(),
                 program: this.ID,