[Aptos Framework][Token] fully support deletion of TokenData and Token if reach 0

aptos-move/framework/aptos-stdlib/sources/simple_map.move

@@ -2,7 +2,7 @@
 /// 1) Keys point to Values
 /// 2) Each Key must be unique
 /// 3) A Key can be found within O(Log N) time
-/// 4) The data is stored as a sorted by Key
+/// 4) The data is stored as sorted by Key
 /// 5) Adds and removals take O(N) time
 module aptos_std::simple_map {
     use std::error;
@@ -119,7 +119,7 @@ module aptos_std::simple_map {
         let right = length;
 
         while (left != right) {
-            let mid = (left + right) / 2;
+            let mid = left + (right - left) / 2;
             let potential_key = &vector::borrow(&map.data, mid).key;
             if (comparator::is_smaller_than(&comparator::compare(potential_key, key))) {
                 left = mid + 1;

aptos-move/framework/aptos-token/sources/token.move

@@ -42,7 +42,7 @@ module aptos_token::token {
     const ENO_TOKEN_IN_TOKEN_STORE: u64 = 19;
     const ENON_ZERO_PROPERTY_VERSION_ONLY_ONE_INSTANCE: u64 = 20;
     const EUSER_NOT_OPT_IN_DIRECT_TRANSFER: u64 = 21;
-
+    const EWITHDRAW_ZERO: u64 = 22;
 
     //
     // Core data structures for holding tokens
@@ -505,6 +505,11 @@ module aptos_token::token {
         id: TokenId,
         amount: u64,
     ): Token acquires TokenStore {
+        // It does not make sense to withdraw 0 tokens.
+        assert!(amount > 0, error::invalid_argument(EWITHDRAW_ZERO));
+        // Make sure the account has sufficient tokens to withdraw.
+        assert!(balance_of(account_addr, id) >= amount, error::invalid_argument(EINSUFFICIENT_BALANCE));
+
         let token_store = borrow_global_mut<TokenStore>(account_addr);
         event::emit_event<WithdrawEvent>(
             &mut token_store.withdraw_events,
@@ -519,12 +524,12 @@ module aptos_token::token {
             table::contains(tokens, id),
             error::not_found(EBALANCE_NOT_PUBLISHED),
         );
+        // balance > amount and amount > 0 indirectly asserted that balance > 0.
         let balance = &mut table::borrow_mut(tokens, id).amount;
-        if (id.property_version == 0) {
+        if (*balance > amount) {
             *balance = *balance - amount;
             Token{ id, amount, token_properties: property_map::empty() }
         } else {
-            // only 1 token per property_version > 0. we can directly extract from owner's token store
             table::remove(tokens, id)
         }
     }
@@ -781,8 +786,6 @@ module aptos_token::token {
         amount: u64
     ) acquires Collections, TokenStore {
         let token_id = create_token_id_raw(creators_address, collection, name, property_version);
-        let owner_addr = signer::address_of(owner);
-        assert!(balance_of(owner_addr, token_id) >= amount, EINSUFFICIENT_BALANCE);
         let creator_addr = token_id.token_data_id.creator;
         assert!(
             exists<Collections>(creator_addr),
@@ -795,21 +798,35 @@ module aptos_token::token {
             error::not_found(ETOKEN_NOT_PUBLISHED),
         );
 
-        let token_data = table::borrow_mut(
-            &mut collections.token_data,
-            token_id.token_data_id,
-        );
-
-        let token = withdraw_token(owner, token_id, amount);
-        token_data.supply = token_data.supply - token.amount;
-        let Token { id: _, amount: burned_amount, token_properties: _ } = token;
-
-        let token_store = borrow_global_mut<TokenStore>(owner_addr);
-
+        // Burn the tokens.
+        let Token { id: _, amount: burned_amount, token_properties: _ } = withdraw_token(owner, token_id, amount);
+        let token_store = borrow_global_mut<TokenStore>(signer::address_of(owner));
         event::emit_event<BurnTokenEvent>(
             &mut token_store.burn_events,
             BurnTokenEvent { id: token_id, amount: burned_amount},
         );
+
+        // Decrease the supply correspondingly by the amount of tokens burned.
+        let token_data = table::borrow_mut(
+            &mut collections.token_data,
+            token_id.token_data_id,
+        );
+        token_data.supply = token_data.supply - burned_amount;
+
+        // Delete the token_data if supply drops to 0.
+        if (token_data.supply == 0) {
+            let TokenData {
+                maximum: _,
+                largest_property_version: _,
+                supply: _,
+                uri: _,
+                royalty: _,
+                name: _,
+                description: _,
+                default_properties: _,
+                mutability_config: _,
+            } = table::remove(&mut collections.token_data, token_id.token_data_id);
+        };
     }
 
     public fun create_token_id(token_data_id: TokenDataId, property_version: u64): TokenId {

ecosystem/typescript/sdk/src/aptos_client.test.ts

@@ -396,7 +396,7 @@ test(
 
     // Transfer Token from Alice's Account to Bob's Account
     await tokenClient.getCollectionData(alice.address().hex(), collectionName);
-    let aliceBalance = await tokenClient.getTokenBalanceForAccount(alice.address().hex(), tokenId);
+    let aliceBalance = await tokenClient.getTokenForAccount(alice.address().hex(), tokenId);
     expect(aliceBalance.amount).toBe("1");
 
     const entryFunctionPayload = new TxnBuilderTypes.TransactionPayloadEntryFunction(
@@ -452,10 +452,10 @@ test(
     const transaction = await client.getTransactionByHash(transactionRes.hash);
     expect((transaction as any)?.success).toBe(true);
 
-    aliceBalance = await tokenClient.getTokenBalanceForAccount(alice.address().hex(), tokenId);
+    aliceBalance = await tokenClient.getTokenForAccount(alice.address().hex(), tokenId);
     expect(aliceBalance.amount).toBe("0");
 
-    const bobBalance = await tokenClient.getTokenBalanceForAccount(bob.address().hex(), tokenId);
+    const bobBalance = await tokenClient.getTokenForAccount(bob.address().hex(), tokenId);
     expect(bobBalance.amount).toBe("1");
   },
   30 * 1000,

ecosystem/typescript/sdk/src/token_client.test.ts

@@ -65,34 +65,34 @@ test(
 
     // Transfer Token from Alice's Account to Bob's Account
     await tokenClient.getCollectionData(alice.address().hex(), collectionName);
-    let aliceBalance = await tokenClient.getTokenBalanceForAccount(alice.address().hex(), tokenId);
+    let aliceBalance = await tokenClient.getTokenForAccount(alice.address().hex(), tokenId);
     expect(aliceBalance.amount).toBe("1");
     const tokenData = await tokenClient.getTokenData(alice.address().hex(), collectionName, tokenName);
     expect(tokenData.name).toBe(tokenName);
 
     await ensureTxnSuccess(
       tokenClient.offerToken(alice, bob.address().hex(), alice.address().hex(), collectionName, tokenName, 1),
     );
-    aliceBalance = await tokenClient.getTokenBalanceForAccount(alice.address().hex(), tokenId);
+    aliceBalance = await tokenClient.getTokenForAccount(alice.address().hex(), tokenId);
     expect(aliceBalance.amount).toBe("0");
 
     await ensureTxnSuccess(
       tokenClient.cancelTokenOffer(alice, bob.address().hex(), alice.address().hex(), collectionName, tokenName),
     );
-    aliceBalance = await tokenClient.getTokenBalanceForAccount(alice.address().hex(), tokenId);
+    aliceBalance = await tokenClient.getTokenForAccount(alice.address().hex(), tokenId);
     expect(aliceBalance.amount).toBe("1");
 
     await ensureTxnSuccess(
       tokenClient.offerToken(alice, bob.address().hex(), alice.address().hex(), collectionName, tokenName, 1),
     );
-    aliceBalance = await tokenClient.getTokenBalanceForAccount(alice.address().hex(), tokenId);
+    aliceBalance = await tokenClient.getTokenForAccount(alice.address().hex(), tokenId);
     expect(aliceBalance.amount).toBe("0");
 
     await ensureTxnSuccess(
       tokenClient.claimToken(bob, alice.address().hex(), alice.address().hex(), collectionName, tokenName),
     );
 
-    const bobBalance = await tokenClient.getTokenBalanceForAccount(bob.address().hex(), tokenId);
+    const bobBalance = await tokenClient.getTokenForAccount(bob.address().hex(), tokenId);
     expect(bobBalance.amount).toBe("1");
   },
   30 * 1000,

ecosystem/typescript/sdk/src/token_client.ts

@@ -307,7 +307,7 @@ export class TokenClient {
   /**
    * Queries token balance for the token creator
    */
-  async getTokenBalance(
+  async getToken(
     creator: MaybeHexString,
     collectionName: string,
     tokenName: string,
@@ -318,7 +318,7 @@ export class TokenClient {
       collection: collectionName,
       name: tokenName,
     };
-    return this.getTokenBalanceForAccount(creator, {
+    return this.getTokenForAccount(creator, {
       token_data_id: tokenDataId,
       property_version,
     });
@@ -347,7 +347,7 @@ export class TokenClient {
    * }
    * ```
    */
-  async getTokenBalanceForAccount(account: MaybeHexString, tokenId: TokenTypes.TokenId): Promise<TokenTypes.Token> {
+  async getTokenForAccount(account: MaybeHexString, tokenId: TokenTypes.TokenId): Promise<TokenTypes.Token> {
     const tokenStore: { type: Gen.MoveStructTag; data: any } = await this.aptosClient.getAccountResource(
       account,
       "0x3::token::TokenStore",
@@ -360,6 +360,16 @@ export class TokenClient {
       key: tokenId,
     };
 
-    return this.aptosClient.getTableItem(handle, getTokenTableItemRequest);
+    try {
+      return await this.aptosClient.getTableItem(handle, getTokenTableItemRequest);
+    } catch (error) {
+      if (error.status === 404) {
+        return {
+          id: tokenId,
+          amount: "0",
+        };
+      }
+      return error;
+    }
   }
 }

ecosystem/typescript/sdk/src/token_types.ts

@@ -39,7 +39,11 @@ export interface TokenId {
   property_version: string;
 }
 
+/** server will return string for u64 */
+type U64 = string;
+
 export interface Token {
   id: TokenId;
-  amount: number;
+  /** server will return string for u64 */
+  amount: U64;
 }