token-2022: Add confidential transfer with fee instruction (#2988)

* token-2022: add separate transfer with fee instruction

* token-2022: add `TransferWithFee` client code

* apply twoxtx patch

* token-2022: add brief tests for transfer with fee

* Revert "apply twoxtx patch"

This reverts commit ce09d1f.

* token-2022: cargo fmt

* token-2022: uncommenting the rest of the tests

* token-2022: cargo fmt

* token-2022: temporarily reverting to 5f89521

* token-2022: minor

* token-2022: clippy

* token-2022: apply twoxtx patch

* token-2022: fix transfer with fee test

* Revert "token-2022: apply twoxtx patch"

This reverts commit 577e63c.

* token-2022: simplify fee parameter for zkp on client

* token-2022: fix build

Author: samkim-crypto

Cargo.lock

@@ -2,6 +2,7 @@ use crate::client::{ProgramClient, ProgramClientError, SendTransaction};
 use solana_program_test::tokio::time;
 use solana_sdk::{
     account::Account as BaseAccount,
+    epoch_info::EpochInfo,
     hash::Hash,
     instruction::Instruction,
     program_error::ProgramError,
@@ -22,6 +23,7 @@ use spl_token_2022::{
     solana_zk_token_sdk::{
         encryption::{auth_encryption::*, elgamal::*},
         errors::ProofError,
+        instruction::transfer_with_fee::FeeParameters,
     },
     state::{Account, AccountState, Mint},
 };
@@ -1148,6 +1150,80 @@ where
         .await
     }
 
+    /// Transfer tokens confidentially with fee
+    #[allow(clippy::too_many_arguments)]
+    pub async fn confidential_transfer_transfer_with_fee<S2: Signer>(
+        &self,
+        source_token_account: &Pubkey,
+        destination_token_account: &Pubkey,
+        source_token_authority: &S2,
+        amount: u64,
+        source_available_balance: u64,
+        source_elgamal_keypair: &ElGamalKeypair,
+        new_source_decryptable_available_balance: AeCiphertext,
+        epoch_info: &EpochInfo,
+    ) -> TokenResult<T::Output> {
+        let source_state = self.get_account_info(source_token_account).await.unwrap();
+        let source_extension =
+            source_state.get_extension::<confidential_transfer::ConfidentialTransferAccount>()?;
+
+        let destination_state = self
+            .get_account_info(destination_token_account)
+            .await
+            .unwrap();
+        let destination_extension = destination_state
+            .get_extension::<confidential_transfer::ConfidentialTransferAccount>(
+        )?;
+
+        let mint_state = self.get_mint_info().await.unwrap();
+        let transfer_fee_config = mint_state
+            .get_extension::<transfer_fee::TransferFeeConfig>()
+            .unwrap();
+
+        let fee_parameters = transfer_fee_config.get_epoch_fee(epoch_info.epoch);
+
+        let ct_mint = mint_state
+            .get_extension::<confidential_transfer::ConfidentialTransferMint>()
+            .unwrap();
+
+        let proof_data = confidential_transfer::instruction::TransferWithFeeData::new(
+            amount,
+            (
+                source_available_balance,
+                &source_extension.available_balance.try_into().unwrap(),
+            ),
+            source_elgamal_keypair,
+            (
+                &destination_extension.encryption_pubkey.try_into().unwrap(),
+                &ct_mint.auditor_pubkey.try_into().unwrap(),
+            ),
+            FeeParameters {
+                fee_rate_basis_points: u16::from(fee_parameters.transfer_fee_basis_points),
+                maximum_fee: u64::from(fee_parameters.maximum_fee),
+            },
+            &ct_mint
+                .withdraw_withheld_authority_pubkey
+                .try_into()
+                .unwrap(),
+        )
+        .map_err(TokenError::Proof)?;
+
+        self.process_ixs(
+            &confidential_transfer::instruction::transfer_with_fee(
+                &self.program_id,
+                source_token_account,
+                destination_token_account,
+                &self.pubkey,
+                new_source_decryptable_available_balance,
+                &source_token_authority.pubkey(),
+                &[],
+                &proof_data,
+            )?,
+            &[source_token_authority],
+        )
+        .await
+    }
+
     /// Applies the confidential transfer pending balance to the available balance
     pub async fn confidential_transfer_apply_pending_balance<S2: Signer>(
         &self,