Add `get_transparent_balances` to data api.

zcash_client_backend/CHANGELOG.md

@@ -36,6 +36,7 @@ and this library adheres to Rust's notion of
   - `WalletRead::get_all_nullifiers`
   - `WalletRead::get_transparent_receivers`
   - `WalletRead::get_unspent_transparent_outputs`
+  - `WalletRead::get_transparent_balances`
   - `WalletWrite::create_account`
   - `WalletWrite::remove_unmined_tx` (behind the `unstable` feature flag).
   - `WalletWrite::get_next_available_address`

zcash_client_backend/src/data_api.rs

@@ -216,6 +216,14 @@ pub trait WalletRead {
         address: &TransparentAddress,
         max_height: BlockHeight,
     ) -> Result<Vec<WalletTransparentOutput>, Self::Error>;
+
+    /// Returns a mapping from transparent receiver to not-yet-shielded UTXO balance,
+    /// for each address associated with a nonzero balance.
+    fn get_transparent_balances(
+        &self,
+        account: AccountId,
+        max_height: BlockHeight,
+    ) -> Result<HashMap<TransparentAddress, Amount>, Self::Error>;
 }
 
 /// The subset of information that is relevant to this wallet that has been
@@ -563,6 +571,14 @@ pub mod testing {
         ) -> Result<Vec<WalletTransparentOutput>, Self::Error> {
             Ok(Vec::new())
         }
+
+        fn get_transparent_balances(
+            &self,
+            _account: AccountId,
+            _max_height: BlockHeight,
+        ) -> Result<HashMap<TransparentAddress, Amount>, Self::Error> {
+            Ok(HashMap::new())
+        }
     }
 
     impl WalletWrite for MockWalletDb {

zcash_client_sqlite/src/error.rs

@@ -168,6 +168,12 @@ impl From<hdwallet::error::Error> for SqliteClientError {
     }
 }
 
+impl From<TransparentCodecError> for SqliteClientError {
+    fn from(e: TransparentCodecError) -> Self {
+        SqliteClientError::TransparentAddress(e)
+    }
+}
+
 impl From<zcash_primitives::memo::Error> for SqliteClientError {
     fn from(e: zcash_primitives::memo::Error) -> Self {
         SqliteClientError::InvalidMemo(e)

zcash_client_sqlite/src/lib.rs

@@ -271,6 +271,20 @@ impl<P: consensus::Parameters> WalletRead for WalletDb<P> {
             Error::TransparentInputsNotSupported,
         ));
     }
+
+    fn get_transparent_balances(
+        &self,
+        _account: AccountId,
+        _max_height: BlockHeight,
+    ) -> Result<HashMap<TransparentAddress, Amount>, Self::Error> {
+        #[cfg(feature = "transparent-inputs")]
+        return wallet::get_transparent_balances(self, _account, _max_height);
+
+        #[cfg(not(feature = "transparent-inputs"))]
+        return Err(SqliteClientError::BackendError(
+            Error::TransparentInputsNotSupported,
+        ));
+    }
 }
 
 impl<'a, P: consensus::Parameters> WalletRead for DataConnStmtCache<'a, P> {
@@ -391,6 +405,14 @@ impl<'a, P: consensus::Parameters> WalletRead for DataConnStmtCache<'a, P> {
         self.wallet_db
             .get_unspent_transparent_outputs(address, max_height)
     }
+
+    fn get_transparent_balances(
+        &self,
+        account: AccountId,
+        max_height: BlockHeight,
+    ) -> Result<HashMap<TransparentAddress, Amount>, Self::Error> {
+        self.wallet_db.get_transparent_balances(account, max_height)
+    }
 }
 
 impl<'a, P: consensus::Parameters> DataConnStmtCache<'a, P> {

zcash_client_sqlite/src/wallet.rs

@@ -267,8 +267,8 @@ pub(crate) fn get_transparent_receivers<P: consensus::Parameters>(
     let mut ret = HashMap::new();
 
     // Get all UAs derived
-    let mut ua_query =
-        conn.prepare("SELECT address, diversifier_index_be FROM addresses WHERE account = :account")?;
+    let mut ua_query = conn
+        .prepare("SELECT address, diversifier_index_be FROM addresses WHERE account = :account")?;
     let mut rows = ua_query.query(named_params![":account": &u32::from(account)])?;
 
     while let Some(row) = rows.next()? {
@@ -966,7 +966,7 @@ pub(crate) fn get_unspent_transparent_outputs<P: consensus::Parameters>(
          ON tx.id_tx = u.spent_in_tx
          WHERE u.address = ?
          AND u.height <= ?
-         AND block IS NULL",
+         AND tx.block IS NULL",
     )?;
 
     let addr_str = address.encode(&wdb.params);
@@ -1004,6 +1004,38 @@ pub(crate) fn get_unspent_transparent_outputs<P: consensus::Parameters>(
     Ok(utxos)
 }
 
+/// Returns the unspent balance for each transparent address associated with the specified account,
+/// such that the block that included the transaction was mined at a height less than or equal to
+/// the provided `max_height`.
+#[cfg(feature = "transparent-inputs")]
+pub(crate) fn get_transparent_balances<P: consensus::Parameters>(
+    wdb: &WalletDb<P>,
+    account: AccountId,
+    max_height: BlockHeight,
+) -> Result<HashMap<TransparentAddress, Amount>, SqliteClientError> {
+    let mut stmt_blocks = wdb.conn.prepare(
+        "SELECT u.address, SUM(u.value_zat)
+         FROM utxos u
+         LEFT OUTER JOIN transactions tx
+         ON tx.id_tx = u.spent_in_tx
+         WHERE u.received_by_accountt = ?
+         AND u.height <= ?
+         AND tx.block IS NULL",
+    )?;
+
+    let mut res = HashMap::new();
+    let mut rows = stmt_blocks.query(params![u32::from(account), u32::from(max_height)])?;
+    while let Some(row) = rows.next()? {
+        let taddr_str: String = row.get(0)?;
+        let taddr = TransparentAddress::decode(&wdb.params, &taddr_str)?;
+        let value = Amount::from_i64(row.get(1)?).unwrap();
+
+        res.insert(taddr, value);
+    }
+
+    Ok(res)
+}
+
 /// Inserts information about a scanned block into the database.
 #[deprecated(
     note = "This function will be removed in a future release. Use zcash_client_backend::data_api::WalletWrite::advance_by_block instead."