add pending balance and tests for confidetial transfer extension (#471)

* add pending balance and tests for confidetial transfer extension

* moved tests, added functions to legacy

* improve tests, fix lints

* updated solana.dic, fixed test

Author: dvrvsimi

clients/rust-legacy/src/token.rs

@@ -4037,6 +4037,80 @@ where
         ));
         self.process_ixs(&instructions, signing_keypairs).await
     }
+
+    /// Get the pending balance for a confidential transfer account.
+    ///
+    /// This decrypts and combines the low 16 bits and high 48 bits of the pending balance
+    /// into a single u64 value.
+    pub async fn confidential_transfer_get_pending_balance(
+        &self,
+        account: &Pubkey,
+        elgamal_secret_key: &ElGamalSecretKey,
+    ) -> TokenResult<u64> {
+        let account_info = self.get_account_info(account).await?;
+        let confidential_transfer_account =
+            account_info.get_extension::<ConfidentialTransferAccount>()?;
+        let account_info = ApplyPendingBalanceAccountInfo::new(confidential_transfer_account);
+
+        account_info
+            .get_pending_balance(elgamal_secret_key)
+            .map_err(|_| TokenError::AccountDecryption)
+    }
+
+    /// Get the available balance for a confidential transfer account.
+    ///
+    /// This decrypts the decryptable available balance using the provided AES key.
+    pub async fn confidential_transfer_get_available_balance(
+        &self,
+        account: &Pubkey,
+        aes_key: &AeKey,
+    ) -> TokenResult<u64> {
+        let account_info = self.get_account_info(account).await?;
+        let confidential_transfer_account =
+            account_info.get_extension::<ConfidentialTransferAccount>()?;
+        let account_info = ApplyPendingBalanceAccountInfo::new(confidential_transfer_account);
+
+        account_info
+            .get_available_balance(aes_key)
+            .map_err(|_| TokenError::AccountDecryption)
+    }
+
+    /// Get the total balance (pending and available) for a confidential transfer account.
+    ///
+    /// This combines both pending and available balances with overflow protection.
+    pub async fn confidential_transfer_get_total_balance(
+        &self,
+        account: &Pubkey,
+        elgamal_secret_key: &ElGamalSecretKey,
+        aes_key: &AeKey,
+    ) -> TokenResult<u64> {
+        let account_info = self.get_account_info(account).await?;
+        let confidential_transfer_account =
+            account_info.get_extension::<ConfidentialTransferAccount>()?;
+        let account_info = ApplyPendingBalanceAccountInfo::new(confidential_transfer_account);
+
+        account_info
+            .get_total_balance(elgamal_secret_key, aes_key)
+            .map_err(|e| match e {
+                spl_token_2022::error::TokenError::Overflow => TokenError::AccountDecryption,
+                _ => TokenError::AccountDecryption,
+            })
+    }
+
+    /// Check if a confidential transfer account has any pending balance.
+    ///
+    /// This checks whether the pending_balance_credit_counter is greater than zero.
+    pub async fn confidential_transfer_has_pending_balance(
+        &self,
+        account: &Pubkey,
+    ) -> TokenResult<bool> {
+        let account_info = self.get_account_info(account).await?;
+        let confidential_transfer_account =
+            account_info.get_extension::<ConfidentialTransferAccount>()?;
+        let account_info = ApplyPendingBalanceAccountInfo::new(confidential_transfer_account);
+
+        Ok(account_info.has_pending_balance())
+    }
 }
 
 /// Calculates the maximum chunk size for a zero-knowledge proof record