[#114] nns: Add 'DeleteRecord'

Signed-off-by: Alexander Chuprov <a.chuprov@yadro.com>

nns/config.yml

@@ -14,6 +14,12 @@ events:
         type: String
       - name: type
         type: Integer
+  - name: DeleteRecord
+    parameters:
+      - name: name
+        type: String
+      - name: type
+        type: Integer
   - name: DeleteRecords
     parameters:
       - name: name

nns/nns_contract.go

@@ -527,6 +527,50 @@ func deleteRecords(ctx storage.Context, name string, typ RecordType) {
 	runtime.Notify("DeleteRecords", name, typ)
 }
 
+// DeleteRecord delete a record of the specified type by data in the provided domain.
+// Returns false if the record was not found.
+func DeleteRecord(name string, typ RecordType, data string) bool {
+	tokenID := []byte(tokenIDFromName(name))
+	if !checkBaseRecords(typ, data) {
+		panic("invalid record data")
+	}
+	ctx := storage.GetContext()
+	ns := getNameState(ctx, tokenID)
+	ns.checkAdmin()
+	return deleteRecord(ctx, tokenID, name, typ, data)
+}
+
+func deleteRecord(ctx storage.Context, tokenId []byte, name string, typ RecordType, data string) bool {
+	recordsKey := getRecordsKeyByType(tokenId, name, typ)
+
+	var previousKey any
+	it := storage.Find(ctx, recordsKey, storage.KeysOnly)
+	for iterator.Next(it) {
+		key := iterator.Value(it).([]byte)
+		ss := storage.Get(ctx, key).([]byte)
+
+		ns := std.Deserialize(ss).(RecordState)
+		if ns.Name == name && ns.Type == typ && ns.Data == data {
+			previousKey = key
+			continue
+		}
+
+		if previousKey != nil {
+			data := storage.Get(ctx, key)
+			storage.Put(ctx, previousKey, data)
+			previousKey = key
+		}
+	}
+
+	if previousKey == nil {
+		return false
+	}
+
+	storage.Delete(ctx, previousKey)
+	runtime.Notify("DeleteRecord", name, typ)
+	return true
+}
+
 // DeleteDomain deletes the domain with the given name.
 func DeleteDomain(name string) {
 	ctx := storage.GetContext()

rpcclient/nns/client.go

@@ -29,6 +29,12 @@ type AddRecordEvent struct {
 	Type *big.Int
 }
 
+// DeleteRecordEvent represents "DeleteRecord" event emitted by the contract.
+type DeleteRecordEvent struct {
+	Name string
+	Type *big.Int
+}
+
 // DeleteRecordsEvent represents "DeleteRecords" event emitted by the contract.
 type DeleteRecordsEvent struct {
 	Name string
@@ -168,6 +174,44 @@ func (c *Contract) DeleteDomainUnsigned(name string) (*transaction.Transaction,
 	return c.actor.MakeUnsignedCall(c.hash, "deleteDomain", nil, name)
 }
 
+func (c *Contract) scriptForDeleteRecord(name string, typ *big.Int, data string) ([]byte, error) {
+	return smartcontract.CreateCallWithAssertScript(c.hash, "deleteRecord", name, typ, data)
+}
+
+// DeleteRecord creates a transaction invoking `deleteRecord` method of the contract.
+// This transaction is signed and immediately sent to the network.
+// The values returned are its hash, ValidUntilBlock value and error if any.
+func (c *Contract) DeleteRecord(name string, typ *big.Int, data string) (util.Uint256, uint32, error) {
+	script, err := c.scriptForDeleteRecord(name, typ, data)
+	if err != nil {
+		return util.Uint256{}, 0, err
+	}
+	return c.actor.SendRun(script)
+}
+
+// DeleteRecordTransaction creates a transaction invoking `deleteRecord` method of the contract.
+// This transaction is signed, but not sent to the network, instead it's
+// returned to the caller.
+func (c *Contract) DeleteRecordTransaction(name string, typ *big.Int, data string) (*transaction.Transaction, error) {
+	script, err := c.scriptForDeleteRecord(name, typ, data)
+	if err != nil {
+		return nil, err
+	}
+	return c.actor.MakeRun(script)
+}
+
+// DeleteRecordUnsigned creates a transaction invoking `deleteRecord` method of the contract.
+// This transaction is not signed, it's simply returned to the caller.
+// Any fields of it that do not affect fees can be changed (ValidUntilBlock,
+// Nonce), fee values (NetworkFee, SystemFee) can be increased as well.
+func (c *Contract) DeleteRecordUnsigned(name string, typ *big.Int, data string) (*transaction.Transaction, error) {
+	script, err := c.scriptForDeleteRecord(name, typ, data)
+	if err != nil {
+		return nil, err
+	}
+	return c.actor.MakeUnsignedRun(script, nil)
+}
+
 // DeleteRecords creates a transaction invoking `deleteRecords` method of the contract.
 // This transaction is signed and immediately sent to the network.
 // The values returned are its hash, ValidUntilBlock value and error if any.
@@ -510,6 +554,73 @@ func (e *AddRecordEvent) FromStackItem(item *stackitem.Array) error {
 	return nil
 }
 
+// DeleteRecordEventsFromApplicationLog retrieves a set of all emitted events
+// with "DeleteRecord" name from the provided [result.ApplicationLog].
+func DeleteRecordEventsFromApplicationLog(log *result.ApplicationLog) ([]*DeleteRecordEvent, error) {
+	if log == nil {
+		return nil, errors.New("nil application log")
+	}
+
+	var res []*DeleteRecordEvent
+	for i, ex := range log.Executions {
+		for j, e := range ex.Events {
+			if e.Name != "DeleteRecord" {
+				continue
+			}
+			event := new(DeleteRecordEvent)
+			err := event.FromStackItem(e.Item)
+			if err != nil {
+				return nil, fmt.Errorf("failed to deserialize DeleteRecordEvent from stackitem (execution #%d, event #%d): %w", i, j, err)
+			}
+			res = append(res, event)
+		}
+	}
+
+	return res, nil
+}
+
+// FromStackItem converts provided [stackitem.Array] to DeleteRecordEvent or
+// returns an error if it's not possible to do to so.
+func (e *DeleteRecordEvent) FromStackItem(item *stackitem.Array) error {
+	if item == nil {
+		return errors.New("nil item")
+	}
+	arr, ok := item.Value().([]stackitem.Item)
+	if !ok {
+		return errors.New("not an array")
+	}
+	if len(arr) != 2 {
+		return errors.New("wrong number of structure elements")
+	}
+
+	var (
+		index = -1
+		err   error
+	)
+	index++
+	e.Name, err = func(item stackitem.Item) (string, error) {
+		b, err := item.TryBytes()
+		if err != nil {
+			return "", err
+		}
+		if !utf8.Valid(b) {
+			return "", errors.New("not a UTF-8 string")
+		}
+		return string(b), nil
+	}(arr[index])
+	if err != nil {
+		return fmt.Errorf("field Name: %w", err)
+	}
+
+	index++
+	e.Type, err = arr[index].TryInteger()
+	if err != nil {
+		return fmt.Errorf("field Type: %w", err)
+	}
+
+	return nil
+}
+
 // DeleteRecordsEventsFromApplicationLog retrieves a set of all emitted events
 // with "DeleteRecords" name from the provided [result.ApplicationLog].
 func DeleteRecordsEventsFromApplicationLog(log *result.ApplicationLog) ([]*DeleteRecordsEvent, error) {

tests/nns_test.go

@@ -178,6 +178,47 @@ func TestNNSRegister(t *testing.T) {
 
 	c.Invoke(t, stackitem.Null{}, "getRecords", "testdomain.com", int64(nns.TXT))
 
+	cAcc.Invoke(t, stackitem.Null{}, "addRecord",
+		"testdomain.com", int64(nns.TXT), "rec1")
+
+	cAcc.Invoke(t, stackitem.Null{}, "addRecord",
+		"testdomain.com", int64(nns.TXT), "rec2")
+
+	cAcc.Invoke(t, stackitem.Null{}, "addRecord",
+		"testdomain.com", int64(nns.TXT), "rec3")
+
+	cAcc.Invoke(t, stackitem.Null{}, "addRecord",
+		"testdomain.com", int64(nns.TXT), "rec4")
+
+	cAcc.Invoke(t, false, "deleteRecord",
+		"testdomain.com", int64(nns.TXT), "rec9999")
+
+	cAcc.Invoke(t, true, "deleteRecord",
+		"testdomain.com", int64(nns.TXT), "rec1")
+
+	expected = stackitem.NewArray([]stackitem.Item{
+		stackitem.NewByteArray([]byte("rec2")),
+		stackitem.NewByteArray([]byte("rec3")),
+		stackitem.NewByteArray([]byte("rec4")),
+	})
+	c.Invoke(t, expected, "getRecords", "testdomain.com", int64(nns.TXT))
+
+	cAcc.Invoke(t, true, "deleteRecord",
+		"testdomain.com", int64(nns.TXT), "rec4")
+
+	cAcc.Invoke(t, true, "deleteRecord",
+		"testdomain.com", int64(nns.TXT), "rec2")
+
+	expected = stackitem.NewArray([]stackitem.Item{
+		stackitem.NewByteArray([]byte("rec3")),
+	})
+	c.Invoke(t, expected, "getRecords", "testdomain.com", int64(nns.TXT))
+
+	cAcc.Invoke(t, true, "deleteRecord",
+		"testdomain.com", int64(nns.TXT), "rec3")
+
+	c.Invoke(t, stackitem.Null{}, "getRecords", "testdomain.com", int64(nns.TXT))
+
 	tx = cAcc.Invoke(t, stackitem.Null{}, "deleteDomain", "testdomain.com")
 	expected = stackitem.NewArray([]stackitem.Item{stackitem.NewByteArray([]byte("testdomain.com")),
 		stackitem.NewBigInteger(big.NewInt(int64(nns.CNAME)))})