token-2022: add new offchain extra metas helper

token/client/src/token.rs

@@ -938,6 +938,7 @@ where
         if let Some(transfer_hook_accounts) = &self.transfer_hook_accounts {
             instruction.accounts.extend(transfer_hook_accounts.clone());
         } else {
+            #[allow(deprecated)]
             offchain::resolve_extra_transfer_account_metas(
                 &mut instruction,
                 |address| {

token/program-2022/src/offchain.rs

@@ -43,6 +43,10 @@ use {
 /// (source, mint, destination, authority, and validation state), wheras the
 /// transfer instruction only requires four (source, mint, destination, and
 /// authority) in addition to `n` number of multisig authorities.
+#[deprecated(
+    since = "1.1.0",
+    note = "Please use `create_transfer_instruction_with_extra_metas` instead"
+)]
 pub async fn resolve_extra_transfer_account_metas<F, Fut>(
     instruction: &mut Instruction,
     fetch_account_data_fn: F,
@@ -92,3 +96,96 @@ where
     }
     Ok(())
 }
+
+/// Offchain helper to create a `TransferChecked` instruction with all
+/// additional required account metas.
+///
+/// To be client-agnostic and to avoid pulling in the full solana-sdk, this
+/// simply takes a function that will return its data as `Future<Vec<u8>>` for
+/// the given address. Can be called in the following way:
+///
+/// ```rust,ignore
+/// use futures_util::TryFutureExt;
+/// use solana_client::nonblocking::rpc_client::RpcClient;
+/// use solana_program::pubkey::Pubkey;
+///
+/// let mint = Pubkey::new_unique();
+/// let client = RpcClient::new_mock("succeeds".to_string());
+/// let mut account_metas = vec![];
+///
+/// get_extra_transfer_account_metas(
+///     &mut account_metas,
+///     |address| self.client.get_account(&address).map_ok(|opt| opt.map(|acc| acc.data)),
+///     &mint,
+/// ).await?;
+/// ```
+/// Note that this offchain helper will build a new `Execute` instruction,
+/// resolve the extra account metas, and then add them to the transfer
+/// instruction. This is because the extra account metas are configured
+/// specifically for the `Execute` instruction, which requires five accounts
+/// (source, mint, destination, authority, and validation state), wheras the
+/// transfer instruction only requires four (source, mint, destination, and
+/// authority) in addition to `n` number of multisig authorities.
+pub async fn create_transfer_instruction_with_extra_metas<F, Fut>(
+    token_program_id: &Pubkey,
+    source_pubkey: &Pubkey,
+    mint_pubkey: &Pubkey,
+    destination_pubkey: &Pubkey,
+    authority_pubkey: &Pubkey,
+    signer_pubkeys: &[&Pubkey],
+    amount: u64,
+    decimals: u8,
+    fetch_account_data_fn: F,
+) -> Result<Instruction, AccountFetchError>
+where
+    F: Fn(Pubkey) -> Fut,
+    Fut: Future<Output = AccountDataResult>,
+{
+    let mut transfer_ix = crate::instruction::transfer_checked(
+        token_program_id,
+        source_pubkey,
+        mint_pubkey,
+        destination_pubkey,
+        authority_pubkey,
+        signer_pubkeys,
+        amount,
+        decimals,
+    )?;
+
+    if token_program_id == &crate::id() {
+        let mint_data = fetch_account_data_fn(*mint_pubkey)
+            .await?
+            .ok_or(ProgramError::InvalidAccountData)?;
+        let mint = StateWithExtensions::<Mint>::unpack(&mint_data)?;
+
+        if let Some(program_id) = transfer_hook::get_program_id(&mint) {
+            // Convert the transfer instruction into an `Execute` instruction,
+            // then resolve the extra account metas as configured in the validation
+            // account data, then finally add the extra account metas to the original
+            // transfer instruction.
+            let mut execute_ix = spl_transfer_hook_interface::instruction::execute(
+                &program_id,
+                source_pubkey,
+                mint_pubkey,
+                destination_pubkey,
+                authority_pubkey,
+                &get_extra_account_metas_address(mint_pubkey, &program_id),
+                amount,
+            );
+
+            resolve_extra_account_metas(
+                &mut execute_ix,
+                fetch_account_data_fn,
+                mint_pubkey,
+                &program_id,
+            )
+            .await?;
+
+            transfer_ix
+                .accounts
+                .extend_from_slice(&execute_ix.accounts[5..]);
+        }
+    }
+
+    Ok(transfer_ix)
+}