Merge pull request #502 from oasisprotocol/mitjat/committeekind-compat

nodeapi: Make CommitteeKind compatbile across cobalt and damask

storage/oasis/nodeapi/api.go

@@ -190,7 +190,12 @@ type (
 
 type (
 	Validator scheduler.Validator
-	Committee scheduler.Committee
+	Committee struct {
+		Kind      CommitteeKind
+		Members   []*scheduler.CommitteeNode
+		RuntimeID coreCommon.Namespace
+		ValidFor  beacon.EpochTime
+	}
 )
 
 // .................... Governance ....................

storage/oasis/nodeapi/cobalt/convert.go

@@ -394,7 +394,7 @@ func convertCommittee(c schedulerCobalt.Committee) nodeapi.Committee {
 		}
 	}
 	return nodeapi.Committee{
-		Kind:      scheduler.CommitteeKind(c.Kind), // We assume the enum is backwards-compatible.
+		Kind:      nodeapi.CommitteeKind(c.Kind), // The enum is compatible between Cobalt and Damask.
 		Members:   members,
 		RuntimeID: c.RuntimeID,
 		ValidFor:  c.ValidFor,

storage/oasis/nodeapi/compat_types.go

@@ -0,0 +1,56 @@
+// The nodeapi package provides a low-level interface to the Oasis node API.
+// The types that it exposes are simplified versions of the types exposed by
+// oasis-core Damask: The top-level type structs are defined in api.go, and
+// the types of their fields are almost universally directly the types exposed
+// by oasis-core Damask. The reason is that as oasis-core evolves, Damask types
+// are mostly able to represent all the information from Cobalt, plus some.
+//
+// This file contains the exceptions to the above rule: It provides substitute
+// types for those Damask types that cannot express Cobalt information.
+
+package nodeapi
+
+import "fmt"
+
+// Copy-pasted from Cobalt; Damask does not support the "storage" kind.
+type CommitteeKind uint8
+
+const (
+	KindInvalid         CommitteeKind = 0
+	KindComputeExecutor CommitteeKind = 1
+	KindStorage         CommitteeKind = 2
+
+	// MaxCommitteeKind is a dummy value used for iterating all committee kinds.
+	MaxCommitteeKind = 3
+
+	KindInvalidName         = "invalid"
+	KindComputeExecutorName = "executor"
+	KindStorageName         = "storage"
+)
+
+// MarshalText encodes a CommitteeKind into text form.
+func (k CommitteeKind) MarshalText() ([]byte, error) {
+	switch k {
+	case KindInvalid:
+		return []byte(KindInvalidName), nil
+	case KindComputeExecutor:
+		return []byte(KindComputeExecutorName), nil
+	case KindStorage:
+		return []byte(KindStorageName), nil
+	default:
+		return nil, fmt.Errorf("invalid role: %d", k)
+	}
+}
+
+// UnmarshalText decodes a text slice into a CommitteeKind.
+func (k *CommitteeKind) UnmarshalText(text []byte) error {
+	switch string(text) {
+	case KindComputeExecutorName:
+		*k = KindComputeExecutor
+	case KindStorageName:
+		*k = KindStorage
+	default:
+		return fmt.Errorf("invalid role: %s", string(text))
+	}
+	return nil
+}

storage/oasis/nodeapi/damask/node.go

@@ -174,7 +174,12 @@ func (c *DamaskConsensusApiLite) GetCommittees(ctx context.Context, height int64
 	}
 	committees := make([]nodeapi.Committee, len(rsp))
 	for i, c := range rsp {
-		committees[i] = nodeapi.Committee(*c)
+		committees[i] = nodeapi.Committee{
+			Kind:      nodeapi.CommitteeKind(c.Kind), // The enum is compatible between Cobalt and Damask.
+			Members:   c.Members,
+			RuntimeID: c.RuntimeID,
+			ValidFor:  c.ValidFor,
+		}
 	}
 	return committees, nil
 }