[#266] nns: Keep isAvailable in sync with register

If conflicting records '*.domain' are present on new domain
registration, then `isAvailable` should return false for this
domain. Ref.
f25296b.

Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>

Author: AnnaShaleva

nns/nns_contract.go

@@ -224,7 +224,7 @@ func GetPrice() int {
 
 // IsAvailable checks whether the provided domain name is available.
 func IsAvailable(name string) bool {
-	fragments := splitAndCheck(name, false)
+	fragments := splitAndCheck(name, true)
 	if fragments == nil {
 		panic("invalid domain name format")
 	}
@@ -236,7 +236,25 @@ func IsAvailable(name string) bool {
 		}
 		return true
 	}
-	return parentExpired(ctx, 0, fragments)
+	if !parentExpired(ctx, 0, fragments) {
+		return false
+	}
+	return len(getParentConflictingRecord(ctx, name, fragments)) == 0
+}
+
+func getParentConflictingRecord(ctx storage.Context, name string, fragments []string) string {
+	parentKey := getTokenKey([]byte(name[len(fragments[0])+1:]))
+	parentRecKey := append([]byte{prefixRecord}, parentKey...)
+	it := storage.Find(ctx, parentRecKey, storage.ValuesOnly|storage.DeserializeValues)
+	suffix := []byte(name)
+	for iterator.Next(it) {
+		r := iterator.Value(it).(RecordState)
+		ind := std.MemorySearchLastIndex([]byte(r.Name), suffix, len(r.Name))
+		if ind > 0 && ind+len(suffix) == len(r.Name) {
+			return r.Name
+		}
+	}
+	return ""
 }
 
 // parentExpired returns true if any domain from fragments doesn't exist or is expired.
@@ -290,15 +308,8 @@ func Register(name string, owner interop.Hash160, email string, refresh, retry,
 		ns := std.Deserialize(nsBytes.([]byte)).(NameState)
 		ns.checkAdmin()
 
-		parentRecKey := append([]byte{prefixRecord}, parentKey...)
-		it := storage.Find(ctx, parentRecKey, storage.ValuesOnly|storage.DeserializeValues)
-		suffix := []byte(name)
-		for iterator.Next(it) {
-			r := iterator.Value(it).(RecordState)
-			ind := std.MemorySearchLastIndex([]byte(r.Name), suffix, len(r.Name))
-			if ind > 0 && ind+len(suffix) == len(r.Name) {
-				panic("parent domain has conflicting records: " + r.Name)
-			}
+		if conflict := getParentConflictingRecord(ctx, name, fragments); len(conflict) != 0 {
+			panic("parent domain has conflicting records: " + conflict)
 		}
 	}
 

tests/nns_test.go

@@ -178,11 +178,13 @@ func TestNNSRegisterMulti(t *testing.T) {
 		"another.fs.neo.com", int64(nns.A), "4.3.2.1")
 
 	c2 = c.WithSigners(acc, acc2)
+	c2.Invoke(t, stackitem.NewBool(false), "isAvailable", "mainnet.fs.neo.com")
 	c2.InvokeFail(t, "parent domain has conflicting records: something.mainnet.fs.neo.com",
 		"register", args...)
 
 	c1.Invoke(t, stackitem.Null{}, "deleteRecords",
 		"something.mainnet.fs.neo.com", int64(nns.A))
+	c2.Invoke(t, stackitem.NewBool(true), "isAvailable", "mainnet.fs.neo.com")
 	c2.Invoke(t, true, "register", args...)
 
 	c2 = c.WithSigners(acc2)