Beacon state: Add interfaces (#8544)

* Define Readonly and writeonly

* Comment

* First take at clean up

* Completed interfaces

* Fix build and test

* Reordering interfaces

* Add build.bazel

* Add build.bazel

* Fix visibility

beacon-chain/blockchain/BUILD.bazel

@@ -43,6 +43,7 @@ go_library(
         "//beacon-chain/p2p:go_default_library",
         "//beacon-chain/powchain:go_default_library",
         "//beacon-chain/state:go_default_library",
+        "//beacon-chain/state/interface:go_default_library",
         "//beacon-chain/state/stategen:go_default_library",
         "//cmd/beacon-chain/flags:go_default_library",
         "//proto/beacon/p2p/v1:go_default_library",

beacon-chain/blockchain/head.go

@@ -13,6 +13,7 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
 	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/sirupsen/logrus"
@@ -268,7 +269,7 @@ func (s *Service) cacheJustifiedStateBalances(ctx context.Context, justifiedRoot
 	epoch := helpers.CurrentEpoch(justifiedState)
 
 	justifiedBalances := make([]uint64, justifiedState.NumValidators())
-	if err := justifiedState.ReadFromEveryValidator(func(idx int, val stateTrie.ReadOnlyValidator) error {
+	if err := justifiedState.ReadFromEveryValidator(func(idx int, val iface.ReadOnlyValidator) error {
 		if helpers.IsActiveValidatorUsingTrie(val, epoch) {
 			justifiedBalances[idx] = val.EffectiveBalance()
 		} else {

beacon-chain/core/blocks/BUILD.bazel

@@ -27,6 +27,7 @@ go_library(
         "//beacon-chain/core/helpers:go_default_library",
         "//beacon-chain/core/validators:go_default_library",
         "//beacon-chain/state:go_default_library",
+        "//beacon-chain/state/interface:go_default_library",
         "//proto/beacon/p2p/v1:go_default_library",
         "//shared/attestationutil:go_default_library",
         "//shared/bls:go_default_library",

beacon-chain/core/blocks/attester_slashing.go

@@ -10,6 +10,7 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	v "github.com/prysmaticlabs/prysm/beacon-chain/core/validators"
 	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	"github.com/prysmaticlabs/prysm/shared/attestationutil"
 	"github.com/prysmaticlabs/prysm/shared/slashutil"
 	"github.com/prysmaticlabs/prysm/shared/sliceutil"
@@ -55,7 +56,7 @@ func ProcessAttesterSlashings(
 		currentEpoch := helpers.SlotToEpoch(beaconState.Slot())
 		var err error
 		var slashedAny bool
-		var val stateTrie.ReadOnlyValidator
+		var val iface.ReadOnlyValidator
 		for _, validatorIndex := range slashableIndices {
 			val, err = beaconState.ValidatorAtIndexReadOnly(types.ValidatorIndex(validatorIndex))
 			if err != nil {

beacon-chain/core/blocks/exit.go

@@ -10,6 +10,7 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	v "github.com/prysmaticlabs/prysm/beacon-chain/core/validators"
 	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	"github.com/prysmaticlabs/prysm/shared/params"
 )
@@ -93,7 +94,7 @@ func ProcessVoluntaryExits(
 //    # Verify signature
 //    domain = get_domain(state, DOMAIN_VOLUNTARY_EXIT, exit.epoch)
 //    assert bls_verify(validator.pubkey, signing_root(exit), exit.signature, domain)
-func VerifyExitAndSignature(validator stateTrie.ReadOnlyValidator, currentSlot types.Slot, fork *pb.Fork, signed *ethpb.SignedVoluntaryExit, genesisRoot []byte) error {
+func VerifyExitAndSignature(validator iface.ReadOnlyValidator, currentSlot types.Slot, fork *pb.Fork, signed *ethpb.SignedVoluntaryExit, genesisRoot []byte) error {
 	if signed == nil || signed.Exit == nil {
 		return errors.New("nil exit")
 	}
@@ -129,7 +130,7 @@ func VerifyExitAndSignature(validator stateTrie.ReadOnlyValidator, currentSlot t
 //    assert get_current_epoch(state) >= exit.epoch
 //    # Verify the validator has been active long enough
 //    assert get_current_epoch(state) >= validator.activation_epoch + SHARD_COMMITTEE_PERIOD
-func verifyExitConditions(validator stateTrie.ReadOnlyValidator, currentSlot types.Slot, exit *ethpb.VoluntaryExit) error {
+func verifyExitConditions(validator iface.ReadOnlyValidator, currentSlot types.Slot, exit *ethpb.VoluntaryExit) error {
 	currentEpoch := helpers.SlotToEpoch(currentSlot)
 	// Verify the validator is active.
 	if !helpers.IsActiveValidatorUsingTrie(validator, currentEpoch) {

beacon-chain/core/epoch/precompute/BUILD.bazel

@@ -16,6 +16,7 @@ go_library(
     deps = [
         "//beacon-chain/core/helpers:go_default_library",
         "//beacon-chain/state:go_default_library",
+        "//beacon-chain/state/interface:go_default_library",
         "//proto/beacon/p2p/v1:go_default_library",
         "//shared/attestationutil:go_default_library",
         "//shared/mathutil:go_default_library",

beacon-chain/core/epoch/precompute/new.go

@@ -9,6 +9,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"go.opencensus.io/trace"
 )
@@ -25,7 +26,7 @@ func New(ctx context.Context, state *stateTrie.BeaconState) ([]*Validator, *Bala
 	currentEpoch := helpers.CurrentEpoch(state)
 	prevEpoch := helpers.PrevEpoch(state)
 
-	if err := state.ReadFromEveryValidator(func(idx int, val stateTrie.ReadOnlyValidator) error {
+	if err := state.ReadFromEveryValidator(func(idx int, val iface.ReadOnlyValidator) error {
 		// Was validator withdrawable or slashed
 		withdrawable := prevEpoch+1 >= val.WithdrawableEpoch()
 		pVal := &Validator{

beacon-chain/core/epoch/precompute/slashing.go

@@ -5,6 +5,7 @@ import (
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	"github.com/prysmaticlabs/prysm/shared/mathutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
 )
@@ -27,7 +28,7 @@ func ProcessSlashingsPrecompute(state *stateTrie.BeaconState, pBal *Balance) err
 
 	var hasSlashing bool
 	// Iterate through validator list in state, stop until a validator satisfies slashing condition of current epoch.
-	err := state.ReadFromEveryValidator(func(idx int, val stateTrie.ReadOnlyValidator) error {
+	err := state.ReadFromEveryValidator(func(idx int, val iface.ReadOnlyValidator) error {
 		correctEpoch := epochToWithdraw == val.WithdrawableEpoch()
 		if val.Slashed() && correctEpoch {
 			hasSlashing = true

beacon-chain/core/helpers/BUILD.bazel

@@ -33,6 +33,7 @@ go_library(
     deps = [
         "//beacon-chain/cache:go_default_library",
         "//beacon-chain/state:go_default_library",
+        "//beacon-chain/state/interface:go_default_library",
         "//proto/beacon/p2p/v1:go_default_library",
         "//shared/bls:go_default_library",
         "//shared/bytesutil:go_default_library",

beacon-chain/core/helpers/committee.go

@@ -13,6 +13,7 @@ import (
 	"github.com/prysmaticlabs/go-bitfield"
 	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
 	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/hashutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
@@ -275,7 +276,7 @@ func ShuffledIndices(state *stateTrie.BeaconState, epoch types.Epoch) ([]types.V
 	}
 
 	indices := make([]types.ValidatorIndex, 0, state.NumValidators())
-	if err := state.ReadFromEveryValidator(func(idx int, val stateTrie.ReadOnlyValidator) error {
+	if err := state.ReadFromEveryValidator(func(idx int, val iface.ReadOnlyValidator) error {
 		if IsActiveValidatorUsingTrie(val, epoch) {
 			indices = append(indices, types.ValidatorIndex(idx))
 		}

beacon-chain/core/helpers/rewards_penalties.go

@@ -3,6 +3,7 @@ package helpers
 import (
 	types "github.com/prysmaticlabs/eth2-types"
 	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	"github.com/prysmaticlabs/prysm/shared/params"
 )
 
@@ -46,7 +47,7 @@ func TotalBalance(state *stateTrie.BeaconState, indices []types.ValidatorIndex)
 //    return get_total_balance(state, set(get_active_validator_indices(state, get_current_epoch(state))))
 func TotalActiveBalance(state *stateTrie.BeaconState) (uint64, error) {
 	total := uint64(0)
-	if err := state.ReadFromEveryValidator(func(idx int, val stateTrie.ReadOnlyValidator) error {
+	if err := state.ReadFromEveryValidator(func(idx int, val iface.ReadOnlyValidator) error {
 		if IsActiveValidatorUsingTrie(val, SlotToEpoch(state.Slot())) {
 			total += val.EffectiveBalance()
 		}

beacon-chain/core/helpers/validators.go

@@ -7,6 +7,7 @@ import (
 	types "github.com/prysmaticlabs/eth2-types"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	"github.com/prysmaticlabs/prysm/shared/bls"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
@@ -28,7 +29,7 @@ func IsActiveValidator(validator *ethpb.Validator, epoch types.Epoch) bool {
 }
 
 // IsActiveValidatorUsingTrie checks if a read only validator is active.
-func IsActiveValidatorUsingTrie(validator stateTrie.ReadOnlyValidator, epoch types.Epoch) bool {
+func IsActiveValidatorUsingTrie(validator iface.ReadOnlyValidator, epoch types.Epoch) bool {
 	return checkValidatorActiveStatus(validator.ActivationEpoch(), validator.ExitEpoch(), epoch)
 }
 
@@ -50,7 +51,7 @@ func IsSlashableValidator(activationEpoch, withdrawableEpoch types.Epoch, slashe
 }
 
 // IsSlashableValidatorUsingTrie checks if a read only validator is slashable.
-func IsSlashableValidatorUsingTrie(val stateTrie.ReadOnlyValidator, epoch types.Epoch) bool {
+func IsSlashableValidatorUsingTrie(val iface.ReadOnlyValidator, epoch types.Epoch) bool {
 	return checkValidatorSlashable(val.ActivationEpoch(), val.WithdrawableEpoch(), val.Slashed(), epoch)
 }
 
@@ -86,7 +87,7 @@ func ActiveValidatorIndices(state *stateTrie.BeaconState, epoch types.Epoch) ([]
 		return activeIndices, nil
 	}
 	var indices []types.ValidatorIndex
-	if err := state.ReadFromEveryValidator(func(idx int, val stateTrie.ReadOnlyValidator) error {
+	if err := state.ReadFromEveryValidator(func(idx int, val iface.ReadOnlyValidator) error {
 		if IsActiveValidatorUsingTrie(val, epoch) {
 			indices = append(indices, types.ValidatorIndex(idx))
 		}
@@ -118,7 +119,7 @@ func ActiveValidatorCount(state *stateTrie.BeaconState, epoch types.Epoch) (uint
 	}
 
 	count := uint64(0)
-	if err := state.ReadFromEveryValidator(func(idx int, val stateTrie.ReadOnlyValidator) error {
+	if err := state.ReadFromEveryValidator(func(idx int, val iface.ReadOnlyValidator) error {
 		if IsActiveValidatorUsingTrie(val, epoch) {
 			count++
 		}
@@ -320,7 +321,7 @@ func IsEligibleForActivationQueue(validator *ethpb.Validator) bool {
 
 // IsEligibleForActivationQueueUsingTrie checks if the read-only validator is eligible to
 // be placed into the activation queue.
-func IsEligibleForActivationQueueUsingTrie(validator stateTrie.ReadOnlyValidator) bool {
+func IsEligibleForActivationQueueUsingTrie(validator iface.ReadOnlyValidator) bool {
 	return isEligibileForActivationQueue(validator.ActivationEligibilityEpoch(), validator.EffectiveBalance())
 }
 
@@ -349,7 +350,7 @@ func IsEligibleForActivation(state *stateTrie.BeaconState, validator *ethpb.Vali
 }
 
 // IsEligibleForActivationUsingTrie checks if the validator is eligible for activation.
-func IsEligibleForActivationUsingTrie(state *stateTrie.BeaconState, validator stateTrie.ReadOnlyValidator) bool {
+func IsEligibleForActivationUsingTrie(state *stateTrie.BeaconState, validator iface.ReadOnlyValidator) bool {
 	cpt := state.FinalizedCheckpoint()
 	if cpt == nil {
 		return false

beacon-chain/core/validators/BUILD.bazel

@@ -9,6 +9,7 @@ go_library(
     deps = [
         "//beacon-chain/core/helpers:go_default_library",
         "//beacon-chain/state:go_default_library",
+        "//beacon-chain/state/interface:go_default_library",
         "//shared/params:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prysmaticlabs_eth2_types//:go_default_library",

beacon-chain/core/validators/validator.go

@@ -10,6 +10,7 @@ import (
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	"github.com/prysmaticlabs/prysm/shared/params"
 )
 
@@ -45,7 +46,7 @@ func InitiateValidatorExit(state *stateTrie.BeaconState, idx types.ValidatorInde
 		return state, nil
 	}
 	var exitEpochs []types.Epoch
-	err = state.ReadFromEveryValidator(func(idx int, val stateTrie.ReadOnlyValidator) error {
+	err = state.ReadFromEveryValidator(func(idx int, val iface.ReadOnlyValidator) error {
 		if val.ExitEpoch() != params.BeaconConfig().FarFutureEpoch {
 			exitEpochs = append(exitEpochs, val.ExitEpoch())
 		}
@@ -66,7 +67,7 @@ func InitiateValidatorExit(state *stateTrie.BeaconState, idx types.ValidatorInde
 
 	// We use the exit queue churn to determine if we have passed a churn limit.
 	exitQueueChurn := uint64(0)
-	err = state.ReadFromEveryValidator(func(idx int, val stateTrie.ReadOnlyValidator) error {
+	err = state.ReadFromEveryValidator(func(idx int, val iface.ReadOnlyValidator) error {
 		if val.ExitEpoch() == exitQueueEpoch {
 			exitQueueChurn++
 		}

beacon-chain/rpc/beacon/BUILD.bazel

@@ -36,6 +36,7 @@ go_library(
         "//beacon-chain/p2p:go_default_library",
         "//beacon-chain/powchain:go_default_library",
         "//beacon-chain/state:go_default_library",
+        "//beacon-chain/state/interface:go_default_library",
         "//beacon-chain/state/stategen:go_default_library",
         "//beacon-chain/sync:go_default_library",
         "//proto/beacon/p2p/v1:go_default_library",

beacon-chain/rpc/beacon/validators_stream.go

@@ -23,6 +23,7 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/db"
 	"github.com/prysmaticlabs/prysm/beacon-chain/powchain"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/event"
 	"github.com/prysmaticlabs/prysm/shared/params"
@@ -298,7 +299,7 @@ func (is *infostream) generateValidatorsInfo(pubKeys [][]byte) ([]*ethpb.Validat
 }
 
 // generateValidatorInfo generates the validator info for a public key.
-func (is *infostream) generateValidatorInfo(pubKey []byte, validator state.ReadOnlyValidator, headState *state.BeaconState, epoch types.Epoch) (*ethpb.ValidatorInfo, error) {
+func (is *infostream) generateValidatorInfo(pubKey []byte, validator iface.ReadOnlyValidator, headState *state.BeaconState, epoch types.Epoch) (*ethpb.ValidatorInfo, error) {
 	info := &ethpb.ValidatorInfo{
 		PublicKey: pubKey,
 		Epoch:     epoch,
@@ -385,7 +386,7 @@ func (is *infostream) calculateActivationTimeForPendingValidators(res []*ethpb.V
 	numAttestingValidators := uint64(0)
 	pendingValidators := make([]types.ValidatorIndex, 0, headState.NumValidators())
 
-	err := headState.ReadFromEveryValidator(func(idx int, val state.ReadOnlyValidator) error {
+	err := headState.ReadFromEveryValidator(func(idx int, val iface.ReadOnlyValidator) error {
 		if val.IsNil() {
 			return errors.New("nil validator in state")
 		}
@@ -471,7 +472,7 @@ func (s indicesSorter) Less(i, j int) bool {
 	return s.indices[i] < s.indices[j]
 }
 
-func (is *infostream) calculateStatusAndTransition(validator state.ReadOnlyValidator, currentEpoch types.Epoch) (ethpb.ValidatorStatus, uint64) {
+func (is *infostream) calculateStatusAndTransition(validator iface.ReadOnlyValidator, currentEpoch types.Epoch) (ethpb.ValidatorStatus, uint64) {
 	farFutureEpoch := params.BeaconConfig().FarFutureEpoch
 
 	if validator.IsNil() {

beacon-chain/state/BUILD.bazel

@@ -28,6 +28,7 @@ go_library(
     ],
     deps = [
         "//beacon-chain/core/state/stateutils:go_default_library",
+        "//beacon-chain/state/interface:go_default_library",
         "//beacon-chain/state/stateutil:go_default_library",
         "//proto/beacon/p2p/v1:go_default_library",
         "//shared/bytesutil:go_default_library",
@@ -58,6 +59,7 @@ go_test(
     ],
     embed = [":go_default_library"],
     deps = [
+        "//beacon-chain/state/interface:go_default_library",
         "//beacon-chain/state/stateutil:go_default_library",
         "//proto/beacon/p2p/v1:go_default_library",
         "//shared/bytesutil:go_default_library",

beacon-chain/state/getters.go

@@ -8,6 +8,7 @@ import (
 	types "github.com/prysmaticlabs/eth2-types"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/go-bitfield"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	pbp2p "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
@@ -504,7 +505,7 @@ func (b *BeaconState) ValidatorAtIndex(idx types.ValidatorIndex) (*ethpb.Validat
 
 // ValidatorAtIndexReadOnly is the validator at the provided index. This method
 // doesn't clone the validator.
-func (b *BeaconState) ValidatorAtIndexReadOnly(idx types.ValidatorIndex) (ReadOnlyValidator, error) {
+func (b *BeaconState) ValidatorAtIndexReadOnly(idx types.ValidatorIndex) (iface.ReadOnlyValidator, error) {
 	if !b.hasInnerState() {
 		return ReadOnlyValidator{}, ErrNilInnerState
 	}
@@ -573,7 +574,7 @@ func (b *BeaconState) NumValidators() int {
 
 // ReadFromEveryValidator reads values from every validator and applies it to the provided function.
 // Warning: This method is potentially unsafe, as it exposes the actual validator registry.
-func (b *BeaconState) ReadFromEveryValidator(f func(idx int, val ReadOnlyValidator) error) error {
+func (b *BeaconState) ReadFromEveryValidator(f func(idx int, val iface.ReadOnlyValidator) error) error {
 	if !b.hasInnerState() {
 		return ErrNilInnerState
 	}

beacon-chain/state/interface/BUILD.bazel

@@ -0,0 +1,14 @@
+load("@prysm//tools/go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["interface.go"],
+    importpath = "github.com/prysmaticlabs/prysm/beacon-chain/state/interface",
+    visibility = ["//beacon-chain:__subpackages__"],
+    deps = [
+        "//proto/beacon/p2p/v1:go_default_library",
+        "@com_github_prysmaticlabs_eth2_types//:go_default_library",
+        "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
+        "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
+    ],
+)