rpc/nns: add a method to resolve NeoFS contracts

Fix #348.

Signed-off-by: Roman Khimov <[email protected]>

rpc/nns/hashes.go

@@ -1,7 +1,10 @@
 package nns
 
 import (
+	"errors"
+
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
+	"github.com/nspcc-dev/neo-go/pkg/encoding/address"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 )
 
@@ -10,6 +13,11 @@ import (
 // an ID of 1.
 const ID = 1
 
+// ContractTLD is the default TLD for NeoFS contracts. It's a convention that
+// is not likely to be used by any non-NeoFS networks, but for NeoFS ones it
+// allows to find contract hashes more easily.
+const ContractTLD = "neofs"
+
 // ContractStateGetter is the interface required for contract state resolution
 // using a known contract ID.
 type ContractStateGetter interface {
@@ -27,3 +35,28 @@ func InferHash(sg ContractStateGetter) (util.Uint160, error) {
 
 	return c.Hash, nil
 }
+
+// ResolveFSContract is a convenience method that doesn't exist in the NNS
+// contract itself (it doesn't care which data is stored there). It assumes
+// that contracts follow the [ContractTLD] convention, gets simple contract
+// names (like "container" or "netmap") and extracts the hash for the
+// respective NNS record in any of the formats (of which historically there's
+// been a few).
+func (c *ContractReader) ResolveFSContract(name string) (util.Uint160, error) {
+	strs, err := c.Resolve(name+"."+ContractTLD, TXT)
+	if err != nil {
+		return util.Uint160{}, err
+	}
+	for i := range strs {
+		h, err := util.Uint160DecodeStringLE(strs[i])
+		if err == nil {
+			return h, nil
+		}
+
+		h, err = address.StringToUint160(strs[i])
+		if err == nil {
+			return h, nil
+		}
+	}
+	return util.Uint160{}, errors.New("no valid hashes are found")
+}

rpc/nns/hashes_test.go

@@ -4,8 +4,12 @@ import (
 	"errors"
 	"testing"
 
+	"github.com/google/uuid"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
+	"github.com/nspcc-dev/neo-go/pkg/encoding/address"
+	"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
 	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
 	"github.com/stretchr/testify/require"
 )
 
@@ -35,3 +39,77 @@ func TestInferHash(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, util.Uint160{0x01, 0x02, 0x03}, h)
 }
+
+type testInv struct {
+	err error
+	res *result.Invoke
+}
+
+func (t *testInv) Call(contract util.Uint160, operation string, params ...any) (*result.Invoke, error) {
+	return t.res, t.err
+}
+
+func (t *testInv) CallAndExpandIterator(contract util.Uint160, operation string, i int, params ...any) (*result.Invoke, error) {
+	return t.res, t.err
+}
+func (t *testInv) TraverseIterator(uuid.UUID, *result.Iterator, int) ([]stackitem.Item, error) {
+	return nil, nil
+}
+func (t *testInv) TerminateSession(uuid.UUID) error {
+	return nil
+}
+
+func TestBaseErrors(t *testing.T) {
+	ti := new(testInv)
+	r := NewReader(ti, util.Uint160{1, 2, 3})
+
+	ti.err = errors.New("bad")
+	_, err := r.ResolveFSContract("blah")
+	require.Error(t, err)
+
+	ti.err = nil
+	ti.res = &result.Invoke{
+		State: "HALT",
+		Stack: []stackitem.Item{
+			stackitem.Make([]stackitem.Item{}),
+		},
+	}
+	_, err = r.ResolveFSContract("blah")
+	require.Error(t, err)
+
+	ti.res = &result.Invoke{
+		State: "HALT",
+		Stack: []stackitem.Item{
+			stackitem.Make([]stackitem.Item{
+				stackitem.Make(100500),
+			}),
+		},
+	}
+	_, err = r.ResolveFSContract("blah")
+	require.Error(t, err)
+
+	h := util.Uint160{1, 2, 3, 4, 5}
+	ti.res = &result.Invoke{
+		State: "HALT",
+		Stack: []stackitem.Item{
+			stackitem.Make([]stackitem.Item{
+				stackitem.Make(h.StringLE()),
+			}),
+		},
+	}
+	res, err := r.ResolveFSContract("blah")
+	require.NoError(t, err)
+	require.Equal(t, h, res)
+
+	ti.res = &result.Invoke{
+		State: "HALT",
+		Stack: []stackitem.Item{
+			stackitem.Make([]stackitem.Item{
+				stackitem.Make(address.Uint160ToString(h)),
+			}),
+		},
+	}
+	res, err = r.ResolveFSContract("blah")
+	require.NoError(t, err)
+	require.Equal(t, h, res)
+}