fix(zcoin): resume previous sync if sync_params are not provided (#1967)

mm2src/coins/z_coin/storage/walletdb/mod.rs

@@ -40,6 +40,7 @@ impl<'a> WalletDbShared {
         zcoin_builder: &ZCoinBuilder<'a>,
         checkpoint_block: Option<CheckPointBlockInfo>,
         z_spending_key: &ExtendedSpendingKey,
+        continue_from_prev_sync: bool,
     ) -> MmResult<Self, WalletDbError> {
         let wallet_db = create_wallet_db(
             zcoin_builder
@@ -48,6 +49,7 @@ impl<'a> WalletDbShared {
             zcoin_builder.protocol_info.consensus_params.clone(),
             checkpoint_block,
             ExtendedFullViewingKey::from(z_spending_key),
+            continue_from_prev_sync,
         )
         .await
         .mm_err(WalletDbError::ZcoinClientInitError)?;

mm2src/coins/z_coin/z_rpc.rs

@@ -365,6 +365,7 @@ pub async fn create_wallet_db(
     consensus_params: ZcoinConsensusParams,
     checkpoint_block: Option<CheckPointBlockInfo>,
     evk: ExtendedFullViewingKey,
+    continue_from_prev_sync: bool,
 ) -> Result<WalletDb<ZcoinConsensusParams>, MmError<ZcoinClientInitError>> {
     async_blocking({
         move || -> Result<WalletDb<ZcoinConsensusParams>, MmError<ZcoinClientInitError>> {
@@ -380,8 +381,14 @@ pub async fn create_wallet_db(
 
             // Check if the initial block height is less than the previous synchronization height and
             // Rewind walletdb to the minimum possible height.
-            if db.get_extended_full_viewing_keys()?.is_empty() || init_block_height != min_sync_height {
-                info!("Older/Newer sync height detected!, rewinding walletdb to new height: {init_block_height:?}");
+            if db.get_extended_full_viewing_keys()?.is_empty()
+                || (!continue_from_prev_sync && init_block_height != min_sync_height)
+            {
+                // let user know we're clearing cache and resyncing from new provided height.
+                if min_sync_height.unwrap_or(0) > 0 {
+                    info!("Older/Newer sync height detected!, rewinding walletdb to new height: {init_block_height:?}");
+                }
+
                 let mut wallet_ops = db.get_update_ops().expect("get_update_ops always returns Ok");
                 wallet_ops
                     .rewind_to_height(u32::MIN.into())
@@ -477,14 +484,18 @@ pub(super) async fn init_light_client<'a>(
     let maybe_checkpoint_block = light_rpc_clients
         .checkpoint_block_from_height(sync_height.max(sapling_activation_height))
         .await?;
-
-    let wallet_db = WalletDbShared::new(builder, maybe_checkpoint_block, z_spending_key)
+    let min_height = blocks_db.get_earliest_block().await?;
+    // check if no sync_params was provided and continue syncing from last height in db if it's > 0.
+    let continue_from_prev_sync = min_height > 0 && sync_params.is_none();
+    let wallet_db = WalletDbShared::new(builder, maybe_checkpoint_block, z_spending_key, continue_from_prev_sync)
         .await
         .mm_err(|err| ZcoinClientInitError::ZcashDBError(err.to_string()))?;
 
-    // Get min_height in blocks_db and rewind blocks_db to 0 if sync_height != min_height
-    let min_height = blocks_db.get_earliest_block().await?;
-    if sync_height != min_height as u64 {
+    if !continue_from_prev_sync && (sync_height != min_height as u64) {
+        // let user know we're clearing cache and resyncing from new provided height.
+        if min_height > 0 {
+            info!("Older/Newer sync height detected!, rewinding blocks_db to new height: {sync_height:?}");
+        }
         blocks_db
             .rewind_to_height(u32::MIN)
             .map_err(|err| ZcoinClientInitError::ZcashDBError(err.to_string()))?;
@@ -546,7 +557,7 @@ pub(super) async fn init_native_client<'a>(
         is_pre_sapling: false,
         actual: checkpoint_height,
     };
-    let wallet_db = WalletDbShared::new(builder, checkpoint_block, z_spending_key)
+    let wallet_db = WalletDbShared::new(builder, checkpoint_block, z_spending_key, true)
         .await
         .mm_err(|err| ZcoinClientInitError::ZcashDBError(err.to_string()))?;