go/staking: Add a Delegations call, and expose over gRPC

This adds a Delegations call in the spirt of DebondingDelegations that
returns a map of delegations for a given delegator.

.changelog/2740.feature.md

@@ -0,0 +1,4 @@
+go/staking: Add a Delegations call, and expose over gRPC
+
+This adds a Delegations call in the spirt of DebondingDelegations that
+returns a map of delegations for a given delegator.

go/consensus/tendermint/apps/staking/query.go

@@ -19,6 +19,7 @@ type Query interface {
 	DebondingInterval(context.Context) (epochtime.EpochTime, error)
 	Accounts(context.Context) ([]signature.PublicKey, error)
 	AccountInfo(context.Context, signature.PublicKey) (*staking.Account, error)
+	Delegations(context.Context, signature.PublicKey) (map[signature.PublicKey]*staking.Delegation, error)
 	DebondingDelegations(context.Context, signature.PublicKey) (map[signature.PublicKey][]*staking.DebondingDelegation, error)
 	Genesis(context.Context) (*staking.Genesis, error)
 }
@@ -91,6 +92,10 @@ func (sq *stakingQuerier) AccountInfo(ctx context.Context, id signature.PublicKe
 	return sq.state.Account(id), nil
 }
 
+func (sq *stakingQuerier) Delegations(ctx context.Context, id signature.PublicKey) (map[signature.PublicKey]*staking.Delegation, error) {
+	return sq.state.DelegationsFor(id)
+}
+
 func (sq *stakingQuerier) DebondingDelegations(ctx context.Context, id signature.PublicKey) (map[signature.PublicKey][]*staking.DebondingDelegation, error) {
 	return sq.state.DebondingDelegationsFor(id)
 }

go/consensus/tendermint/apps/staking/state/state.go

@@ -237,6 +237,33 @@ func (s *ImmutableState) Delegation(delegatorID, escrowID signature.PublicKey) *
 	return &del
 }
 
+func (s *ImmutableState) DelegationsFor(delegatorID signature.PublicKey) (map[signature.PublicKey]*staking.Delegation, error) {
+	delegations := make(map[signature.PublicKey]*staking.Delegation)
+	s.Snapshot.IterateRange(
+		delegationKeyFmt.Encode(),
+		nil,
+		true,
+		func(key, value []byte) bool {
+			var escrowID signature.PublicKey
+			var decDelegatorID signature.PublicKey
+			if !delegationKeyFmt.Decode(key, &escrowID, &decDelegatorID) || !decDelegatorID.Equal(delegatorID) {
+				return true
+			}
+
+			var del staking.Delegation
+			if err := cbor.Unmarshal(value, &del); err != nil {
+				panic("staking: corrupt delegation state: " + err.Error())
+			}
+
+			delegations[escrowID] = &del
+
+			return false
+		},
+	)
+
+	return delegations, nil
+}
+
 func (s *ImmutableState) DebondingDelegations() (map[signature.PublicKey]map[signature.PublicKey][]*staking.DebondingDelegation, error) {
 	delegations := make(map[signature.PublicKey]map[signature.PublicKey][]*staking.DebondingDelegation)
 	s.Snapshot.IterateRange(

go/consensus/tendermint/staking/staking.go

@@ -80,6 +80,15 @@ func (tb *tendermintBackend) AccountInfo(ctx context.Context, query *api.OwnerQu
 	return q.AccountInfo(ctx, query.Owner)
 }
 
+func (tb *tendermintBackend) Delegations(ctx context.Context, query *api.OwnerQuery) (map[signature.PublicKey]*api.Delegation, error) {
+	q, err := tb.querier.QueryAt(ctx, query.Height)
+	if err != nil {
+		return nil, err
+	}
+
+	return q.Delegations(ctx, query.Owner)
+}
+
 func (tb *tendermintBackend) DebondingDelegations(ctx context.Context, query *api.OwnerQuery) (map[signature.PublicKey][]*api.DebondingDelegation, error) {
 	q, err := tb.querier.QueryAt(ctx, query.Height)
 	if err != nil {

go/staking/api/api.go

@@ -84,6 +84,10 @@ type Backend interface {
 	// AccountInfo returns the account descriptor for the given account.
 	AccountInfo(ctx context.Context, query *OwnerQuery) (*Account, error)
 
+	// Delegations returns the list of delegations for the given owner
+	// (delegator).
+	Delegations(ctx context.Context, query *OwnerQuery) (map[signature.PublicKey]*Delegation, error)
+
 	// DebondingDelegations returns the list of debonding delegations for
 	// the given owner (delegator).
 	DebondingDelegations(ctx context.Context, query *OwnerQuery) (map[signature.PublicKey][]*DebondingDelegation, error)

go/staking/api/grpc.go

@@ -25,6 +25,8 @@ var (
 	methodAccounts = serviceName.NewMethod("Accounts", int64(0))
 	// methodAccountInfo is the AccountInfo method.
 	methodAccountInfo = serviceName.NewMethod("AccountInfo", OwnerQuery{})
+	// methodDelegations is the Delegations method.
+	methodDelegations = serviceName.NewMethod("Delegations", OwnerQuery{})
 	// methodDebondingDelegations is the DebondingDelegations method.
 	methodDebondingDelegations = serviceName.NewMethod("DebondingDelegations", OwnerQuery{})
 	// methodStateToGenesis is the StateToGenesis method.
@@ -62,6 +64,10 @@ var (
 				MethodName: methodAccountInfo.ShortName(),
 				Handler:    handlerAccountInfo,
 			},
+			{
+				MethodName: methodDelegations.ShortName(),
+				Handler:    handlerDelegations,
+			},
 			{
 				MethodName: methodDebondingDelegations.ShortName(),
 				Handler:    handlerDebondingDelegations,
@@ -206,6 +212,29 @@ func handlerAccountInfo( // nolint: golint
 	return interceptor(ctx, &query, info, handler)
 }
 
+func handlerDelegations( // nolint: golint
+	srv interface{},
+	ctx context.Context,
+	dec func(interface{}) error,
+	interceptor grpc.UnaryServerInterceptor,
+) (interface{}, error) {
+	var query OwnerQuery
+	if err := dec(&query); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(Backend).Delegations(ctx, &query)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: methodDelegations.FullName(),
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(Backend).Delegations(ctx, req.(*OwnerQuery))
+	}
+	return interceptor(ctx, &query, info, handler)
+}
+
 func handlerDebondingDelegations( // nolint: golint
 	srv interface{},
 	ctx context.Context,
@@ -385,6 +414,14 @@ func (c *stakingClient) AccountInfo(ctx context.Context, query *OwnerQuery) (*Ac
 	return &rsp, nil
 }
 
+func (c *stakingClient) Delegations(ctx context.Context, query *OwnerQuery) (map[signature.PublicKey]*Delegation, error) {
+	var rsp map[signature.PublicKey]*Delegation
+	if err := c.conn.Invoke(ctx, methodDelegations.FullName(), query, &rsp); err != nil {
+		return nil, err
+	}
+	return rsp, nil
+}
+
 func (c *stakingClient) DebondingDelegations(ctx context.Context, query *OwnerQuery) (map[signature.PublicKey][]*DebondingDelegation, error) {
 	var rsp map[signature.PublicKey][]*DebondingDelegation
 	if err := c.conn.Invoke(ctx, methodDebondingDelegations.FullName(), query, &rsp); err != nil {