enforce limit on get nfts for user (#1463)

* enforce limit on get nfts for user

* formatting and use PKID.Eq instead of reflect deepequals

* filter for sale and pending in db

* remove commented out code

* gofmt

Author: lazynina

lib/block_view_nft.go

@@ -94,15 +94,22 @@ func (bav *UtxoView) GetNFTEntriesForPostHash(nftPostHash *BlockHash) []*NFTEntr
 	return nftEntries
 }
 
-func (bav *UtxoView) GetNFTEntriesForPKID(ownerPKID *PKID) []*NFTEntry {
+func (bav *UtxoView) GetNFTEntriesForPKID(
+	ownerPKID *PKID,
+	limit int,
+	lastKeyBytes []byte,
+	isForSale *bool,
+	isPending *bool,
+) ([]*NFTEntry, []byte) {
 	var dbNFTEntries []*NFTEntry
+	var lastSeenKey []byte
 	if bav.Postgres != nil {
 		nfts := bav.Postgres.GetNFTsForPKID(ownerPKID)
 		for _, nft := range nfts {
 			dbNFTEntries = append(dbNFTEntries, nft.NewNFTEntry())
 		}
 	} else {
-		dbNFTEntries = DBGetNFTEntriesForPKID(bav.Handle, ownerPKID)
+		dbNFTEntries, lastSeenKey = DBGetNFTEntriesForPKID(bav.Handle, ownerPKID, limit, lastKeyBytes, isForSale, isPending)
 	}
 
 	// Make sure all of the DB entries are loaded in the view.
@@ -118,11 +125,11 @@ func (bav *UtxoView) GetNFTEntriesForPKID(ownerPKID *PKID) []*NFTEntry {
 	// Loop over the view and build the final set of NFTEntries to return.
 	nftEntries := []*NFTEntry{}
 	for _, nftEntry := range bav.NFTKeyToNFTEntry {
-		if !nftEntry.isDeleted && reflect.DeepEqual(nftEntry.OwnerPKID, ownerPKID) {
+		if !nftEntry.isDeleted && nftEntry.OwnerPKID.Eq(ownerPKID) {
 			nftEntries = append(nftEntries, nftEntry)
 		}
 	}
-	return nftEntries
+	return nftEntries, lastSeenKey
 }
 
 func (bav *UtxoView) GetNFTBidEntriesForPKID(bidderPKID *PKID) (_nftBidEntries []*NFTBidEntry) {

lib/db_utils.go

@@ -8754,18 +8754,75 @@ func DBGetNFTEntryByNFTOwnershipDetails(db *badger.DB, snap *Snapshot, ownerPKID
 }
 
 // DBGetNFTEntriesForPKID gets NFT Entries *from the DB*. Does not include mempool txns.
-func DBGetNFTEntriesForPKID(handle *badger.DB, ownerPKID *PKID) (_nftEntries []*NFTEntry) {
+func DBGetNFTEntriesForPKID(
+	handle *badger.DB,
+	ownerPKID *PKID,
+	limit int,
+	lastKeyBytes []byte,
+	isForSale *bool,
+	isPending *bool,
+) (
+	_nftEntries []*NFTEntry,
+	_lastKeyBytes []byte,
+) {
 	var nftEntries []*NFTEntry
 	prefix := append([]byte{}, Prefixes.PrefixPKIDIsForSaleBidAmountNanosPostHashSerialNumberToNFTEntry...)
 	keyPrefix := append(prefix, ownerPKID[:]...)
-	_, entryByteStringsFound := _enumerateKeysForPrefix(handle, keyPrefix, false, false)
-	for _, byteString := range entryByteStringsFound {
-		currentEntry := &NFTEntry{}
-		rr := bytes.NewReader(byteString)
-		DecodeFromBytes(currentEntry, rr)
-		nftEntries = append(nftEntries, currentEntry)
+	if isForSale != nil {
+		keyPrefix = append(keyPrefix, BoolToByte(*isForSale))
 	}
-	return nftEntries
+	lastSeenKey := keyPrefix
+	haveSeenLastSeenKey := true
+	if len(lastKeyBytes) > 0 {
+		lastSeenKey = lastKeyBytes
+		if limit > 0 {
+			limit += 1
+		}
+	}
+
+	opts := badger.DefaultIteratorOptions
+	opts.Prefix = keyPrefix
+	var lastSeenKeyBytes []byte
+	dbErr := handle.View(func(txn *badger.Txn) error {
+		nodeIterator := txn.NewIterator(opts)
+		defer nodeIterator.Close()
+		for nodeIterator.Seek(lastSeenKey); nodeIterator.ValidForPrefix(keyPrefix); nodeIterator.Next() {
+			// Break if at or beyond limit.
+			if limit > 0 && len(nftEntries) >= limit {
+				break
+			}
+			key := nodeIterator.Item().Key()
+			// Skip if key is before the last seen key. The caller
+			// needs to filter out the lastSeenKey in the view as
+			// we return any key >= the lastSeenKey.
+			if !haveSeenLastSeenKey {
+				if !bytes.Equal(key, lastSeenKey) {
+					continue
+				}
+				haveSeenLastSeenKey = true
+			}
+
+			val, err := nodeIterator.Item().ValueCopy(nil)
+			if err != nil {
+				return err
+			}
+			currentEntry := &NFTEntry{}
+			rr := bytes.NewReader(val)
+			DecodeFromBytes(currentEntry, rr)
+			// If isPending is specified, filter by it.
+			if isPending != nil && currentEntry.IsPending != *isPending {
+				continue
+			}
+			nftEntries = append(nftEntries, currentEntry)
+			lastSeenKeyBytes = append([]byte{}, key...)
+		}
+		return nil
+	})
+	if dbErr != nil {
+		glog.Errorf("DBGetNFTEntriesForPKID: Problem reading NFTEntry, error: (%v)", dbErr)
+	}
+
+	return nftEntries, lastSeenKeyBytes
 }
 
 // =======================================================================================