[#354] api/netmap: Return a slice of parameters directly

`IterateParameters` does a poor job:
- it doesn't encapsulate well, because it returns a pointer,
- it has a clunky interface, compared to range loop.

I have decided to return parameter slice and not `iter.Seq` for 2
reasons:
1. There already is `SetParameters`, so `NetworkConfig` struct is
   expected to be modified.
2. This iterator uses pointers, so even with this interface the slice
   can already be changed.

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

api/netmap/types.go

@@ -577,6 +577,8 @@ type NetworkConfig struct {
 }
 
 // NumberOfParameters returns number of network parameters.
+//
+// Deprecated: use [NetworkConfig.Parameters] instead.
 func (x *NetworkConfig) NumberOfParameters() int {
 	if x != nil {
 		return len(x.ps)
@@ -585,10 +587,20 @@ func (x *NetworkConfig) NumberOfParameters() int {
 	return 0
 }
 
+// Parameters returns an iterator over network parameters.
+func (x *NetworkConfig) Parameters() []NetworkParameter {
+	if x != nil {
+		return x.ps
+	}
+	return nil
+}
+
 // IterateParameters iterates over network parameters.
 // Breaks iteration on f's true return.
 //
 // Handler must not be nil.
+//
+// Deprecated: use [NetworkConfig.Parameters] instead.
 func (x *NetworkConfig) IterateParameters(f func(*NetworkParameter) bool) {
 	if x != nil {
 		for i := range x.ps {

netmap/network_info.go

@@ -30,20 +30,19 @@ func (x *NetworkInfo) readFromV2(m netmap.NetworkInfo, checkFieldPresence bool)
 		return errors.New("missing network config")
 	}
 
-	if checkFieldPresence && c.NumberOfParameters() <= 0 {
+	if checkFieldPresence && len(c.Parameters()) == 0 {
 		return errors.New("missing network parameters")
 	}
 
 	var err error
-	mNames := make(map[string]struct{}, c.NumberOfParameters())
+	mNames := make(map[string]struct{}, len(c.Parameters()))
 
-	c.IterateParameters(func(prm *netmap.NetworkParameter) bool {
+	for _, prm := range c.Parameters() {
 		name := string(prm.GetKey())
 
 		_, was := mNames[name]
 		if was {
-			err = fmt.Errorf("duplicated parameter name: %s", name)
-			return true
+			return fmt.Errorf("duplicated parameter name: %s", name)
 		}
 
 		mNames[name] = struct{}{}
@@ -67,14 +66,8 @@ func (x *NetworkInfo) readFromV2(m netmap.NetworkInfo, checkFieldPresence bool)
 		}
 
 		if err != nil {
-			err = fmt.Errorf("invalid %s parameter: %w", name, err)
+			return fmt.Errorf("invalid %s parameter: %w", name, err)
 		}
-
-		return err != nil
-	})
-
-	if err != nil {
-		return err
 	}
 
 	x.m = m
@@ -152,41 +145,29 @@ func (x *NetworkInfo) setConfig(name string, val []byte) {
 		return
 	}
 
-	found := false
-	prms := make([]netmap.NetworkParameter, 0, c.NumberOfParameters())
-
-	c.IterateParameters(func(prm *netmap.NetworkParameter) bool {
-		found = bytes.Equal(prm.GetKey(), []byte(name))
-		if found {
-			prm.SetValue(val)
-		} else {
-			prms = append(prms, *prm)
+	prms := c.Parameters()
+	for i := range prms {
+		if bytes.Equal(prms[i].GetKey(), []byte(name)) {
+			prms[i].SetValue(val)
+			return
 		}
-
-		return found
-	})
-
-	if !found {
-		prms = append(prms, netmap.NetworkParameter{})
-		prms[len(prms)-1].SetKey([]byte(name))
-		prms[len(prms)-1].SetValue(val)
-
-		c.SetParameters(prms...)
 	}
+
+	prms = append(prms, netmap.NetworkParameter{})
+	prms[len(prms)-1].SetKey([]byte(name))
+	prms[len(prms)-1].SetValue(val)
+
+	c.SetParameters(prms...)
 }
 
 func (x NetworkInfo) configValue(name string) (res []byte) {
-	x.m.GetNetworkConfig().IterateParameters(func(prm *netmap.NetworkParameter) bool {
+	for _, prm := range x.m.GetNetworkConfig().Parameters() {
 		if string(prm.GetKey()) == name {
-			res = prm.GetValue()
-
-			return true
+			return prm.GetValue()
 		}
+	}
 
-		return false
-	})
-
-	return
+	return nil
 }
 
 // SetRawNetworkParameter sets named FrostFS network parameter whose value is
@@ -218,7 +199,7 @@ func (x *NetworkInfo) RawNetworkParameter(name string) []byte {
 func (x *NetworkInfo) IterateRawNetworkParameters(f func(name string, value []byte)) {
 	c := x.m.GetNetworkConfig()
 
-	c.IterateParameters(func(prm *netmap.NetworkParameter) bool {
+	for _, prm := range c.Parameters() {
 		name := string(prm.GetKey())
 		switch name {
 		default:
@@ -237,9 +218,7 @@ func (x *NetworkInfo) IterateRawNetworkParameters(f func(name string, value []by
 			configHomomorphicHashingDisabled,
 			configMaintenanceModeAllowed:
 		}
-
-		return false
-	})
+	}
 }
 
 func (x *NetworkInfo) setConfigUint64(name string, num uint64) {

netmap/network_info_test.go

@@ -76,16 +76,10 @@ func testConfigValue(t *testing.T,
 		var m netmap.NetworkInfo
 		x.WriteToV2(&m)
 
-		require.EqualValues(t, 1, m.GetNetworkConfig().NumberOfParameters())
-		found := false
-		m.GetNetworkConfig().IterateParameters(func(prm *netmap.NetworkParameter) bool {
-			require.False(t, found)
-			require.Equal(t, []byte(v2Key), prm.GetKey())
-			require.Equal(t, v2Val(exp), prm.GetValue())
-			found = true
-			return false
-		})
-		require.True(t, found)
+		var p netmap.NetworkParameter
+		p.SetKey([]byte(v2Key))
+		p.SetValue(v2Val(exp))
+		require.Equal(t, []netmap.NetworkParameter{p}, m.GetNetworkConfig().Parameters())
 	}
 
 	setter(&x, val1)