add offchain helper invoke_transfer_checked_with_fee

Author: tonton-sol

token/program-2022/src/onchain.rs

@@ -3,7 +3,7 @@
 
 use {
     crate::{
-        extension::{transfer_hook, StateWithExtensions},
+        extension::{transfer_fee, transfer_hook, StateWithExtensions},
         instruction,
         state::Mint,
     },
@@ -78,3 +78,70 @@ pub fn invoke_transfer_checked<'a>(
 
     invoke_signed(&cpi_instruction, &cpi_account_infos, seeds)
 }
+
+/// Helper to CPI into token-2022 on-chain, looking through the additional
+/// account infos to create the proper instruction with the proper account infos
+#[allow(clippy::too_many_arguments)]
+pub fn invoke_transfer_checked_with_fee<'a>(
+    token_program_id: &Pubkey,
+    source_info: AccountInfo<'a>,
+    mint_info: AccountInfo<'a>,
+    destination_info: AccountInfo<'a>,
+    authority_info: AccountInfo<'a>,
+    additional_accounts: &[AccountInfo<'a>],
+    amount: u64,
+    decimals: u8,
+    fee: u64,
+    seeds: &[&[&[u8]]],
+) -> ProgramResult {
+    let mut cpi_instruction = transfer_fee::instruction::transfer_checked_with_fee(
+        token_program_id,
+        source_info.key,
+        mint_info.key,
+        destination_info.key,
+        authority_info.key,
+        &[], // add them later, to avoid unnecessary clones
+        amount,
+        decimals,
+        fee,
+    )?;
+
+    let mut cpi_account_infos = vec![
+        source_info.clone(),
+        mint_info.clone(),
+        destination_info.clone(),
+        authority_info.clone(),
+    ];
+
+    // if it's a signer, it might be a multisig signer, throw it in!
+    additional_accounts
+        .iter()
+        .filter(|ai| ai.is_signer)
+        .for_each(|ai| {
+            cpi_account_infos.push(ai.clone());
+            cpi_instruction
+                .accounts
+                .push(AccountMeta::new_readonly(*ai.key, ai.is_signer));
+        });
+
+    // scope the borrowing to avoid a double-borrow during CPI
+    {
+        let mint_data = mint_info.try_borrow_data()?;
+        let mint = StateWithExtensions::<Mint>::unpack(&mint_data)?;
+        if let Some(program_id) = transfer_hook::get_program_id(&mint) {
+            add_extra_accounts_for_execute_cpi(
+                &mut cpi_instruction,
+                &mut cpi_account_infos,
+                &program_id,
+                source_info,
+                mint_info.clone(),
+                destination_info,
+                authority_info,
+                amount,
+                additional_accounts,
+            )?;
+        }
+    }
+
+    invoke_signed(&cpi_instruction, &cpi_account_infos, seeds)
+}