[#1365] morph: Add HomomorphicHashDisabled config getter

Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>

pkg/morph/client/netmap/config.go

@@ -20,6 +20,7 @@ const (
 	etAlphaConfig                 = "EigenTrustAlpha"
 	irCandidateFeeConfig          = "InnerRingCandidateFee"
 	withdrawFeeConfig             = "WithdrawFee"
+	homomorphicHashingDisabledKey = "HomomorphicHashingDisabled"
 )
 
 // MaxObjectSize receives max object size configuration
@@ -109,6 +110,17 @@ func (c *Client) EigenTrustAlpha() (float64, error) {
 	return strconv.ParseFloat(strAlpha, 64)
 }
 
+// HomomorphicHashDisabled returns global configuration value of homomorphic hashing
+// settings.
+func (c *Client) HomomorphicHashDisabled() (bool, error) {
+	hashingDisabled, err := c.readBoolConfig(homomorphicHashingDisabledKey)
+	if err != nil {
+		return false, fmt.Errorf("(%T) could not get homomorphic hash state: %w", c, err)
+	}
+
+	return hashingDisabled, nil
+}
+
 // InnerRingCandidateFee returns global configuration value of fee paid by
 // node to be in inner ring candidates list.
 func (c *Client) InnerRingCandidateFee() (uint64, error) {
@@ -151,6 +163,16 @@ func (c *Client) readStringConfig(key string) (string, error) {
 	return v.(string), nil
 }
 
+func (c *Client) readBoolConfig(key string) (bool, error) {
+	v, err := c.config([]byte(key), BoolAssert)
+	if err != nil {
+		return false, err
+	}
+
+	// BoolAssert is guaranteed to return bool if the error is nil.
+	return v.(bool), nil
+}
+
 // SetConfigPrm groups parameters of SetConfig operation.
 type SetConfigPrm struct {
 	id    []byte
@@ -328,6 +350,11 @@ func StringAssert(item stackitem.Item) (interface{}, error) {
 	return client.StringFromStackItem(item)
 }
 
+// BoolAssert converts stack item to bool.
+func BoolAssert(item stackitem.Item) (interface{}, error) {
+	return client.BoolFromStackItem(item)
+}
+
 // iterateRecords iterates over all config records and passes them to f.
 //
 // Returns f's errors directly.