Event-based state machine

api/cbor_gen.go

@@ -23,6 +23,10 @@ func (t *PaymentInfo) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.Channel (address.Address) (struct)
+	if len("Channel") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"Channel\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("Channel")))); err != nil {
 		return err
 	}
@@ -35,6 +39,10 @@ func (t *PaymentInfo) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.ChannelMessage (cid.Cid) (struct)
+	if len("ChannelMessage") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"ChannelMessage\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("ChannelMessage")))); err != nil {
 		return err
 	}
@@ -53,6 +61,10 @@ func (t *PaymentInfo) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.Vouchers ([]*types.SignedVoucher) (slice)
+	if len("Vouchers") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"Vouchers\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("Vouchers")))); err != nil {
 		return err
 	}
@@ -60,6 +72,10 @@ func (t *PaymentInfo) MarshalCBOR(w io.Writer) error {
 		return err
 	}
 
+	if len(t.Vouchers) > cbg.MaxLength {
+		return xerrors.Errorf("Slice value in field t.Vouchers was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajArray, uint64(len(t.Vouchers)))); err != nil {
 		return err
 	}
@@ -200,6 +216,10 @@ func (t *SealedRef) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.SectorID (uint64) (uint64)
+	if len("SectorID") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"SectorID\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("SectorID")))); err != nil {
 		return err
 	}
@@ -212,6 +232,10 @@ func (t *SealedRef) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.Offset (uint64) (uint64)
+	if len("Offset") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"Offset\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("Offset")))); err != nil {
 		return err
 	}
@@ -224,6 +248,10 @@ func (t *SealedRef) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.Size (uint64) (uint64)
+	if len("Size") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"Size\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("Size")))); err != nil {
 		return err
 	}
@@ -336,6 +364,10 @@ func (t *SealedRefs) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.Refs ([]api.SealedRef) (slice)
+	if len("Refs") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"Refs\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("Refs")))); err != nil {
 		return err
 	}
@@ -343,6 +375,10 @@ func (t *SealedRefs) MarshalCBOR(w io.Writer) error {
 		return err
 	}
 
+	if len(t.Refs) > cbg.MaxLength {
+		return xerrors.Errorf("Slice value in field t.Refs was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajArray, uint64(len(t.Refs)))); err != nil {
 		return err
 	}

chain/deals/client.go

@@ -149,7 +149,7 @@ func (c *Client) onIncoming(deal *ClientDeal) {
 func (c *Client) onUpdated(ctx context.Context, update clientDealUpdate) {
 	log.Infof("Client deal %s updated state to %s", update.id, api.DealStates[update.newState])
 	var deal ClientDeal
-	err := c.deals.Mutate(update.id, func(d *ClientDeal) error {
+	err := c.deals.Get(update.id).Mutate(func(d *ClientDeal) error {
 		d.State = update.newState
 		if update.mut != nil {
 			update.mut(d)
@@ -299,7 +299,7 @@ func (c *Client) List() ([]ClientDeal, error) {
 
 func (c *Client) GetDeal(d cid.Cid) (*ClientDeal, error) {
 	var out ClientDeal
-	if err := c.deals.Get(d, &out); err != nil {
+	if err := c.deals.Get(d).Get(&out); err != nil {
 		return nil, err
 	}
 	return &out, nil

chain/deals/client_utils.go

@@ -151,7 +151,7 @@ func (c *ClientRequestValidator) ValidatePull(
 	}
 
 	var deal ClientDeal
-	err := c.deals.Get(dealVoucher.Proposal, &deal)
+	err := c.deals.Get(dealVoucher.Proposal).Get(&deal)
 	if err != nil {
 		return xerrors.Errorf("Proposal CID %s: %w", dealVoucher.Proposal.String(), ErrNoDeal)
 	}

chain/deals/provider.go

@@ -184,7 +184,7 @@ func (p *Provider) onUpdated(ctx context.Context, update minerDealUpdate) {
 		return
 	}
 	var deal MinerDeal
-	err := p.deals.Mutate(update.id, func(d *MinerDeal) error {
+	err := p.deals.Get(update.id).Mutate(func(d *MinerDeal) error {
 		d.State = update.newState
 		if update.mut != nil {
 			update.mut(d)

chain/deals/provider_utils.go

@@ -23,7 +23,7 @@ import (
 )
 
 func (p *Provider) failDeal(id cid.Cid, cerr error) {
-	if err := p.deals.End(id); err != nil {
+	if err := p.deals.Get(id).End(); err != nil {
 		log.Warnf("deals.End: %s", err)
 	}
 
@@ -167,7 +167,7 @@ func (m *ProviderRequestValidator) ValidatePush(
 	}
 
 	var deal MinerDeal
-	err := m.deals.Get(dealVoucher.Proposal, &deal)
+	err := m.deals.Get(dealVoucher.Proposal).Get(&deal)
 	if err != nil {
 		return xerrors.Errorf("Proposal CID %s: %w", dealVoucher.Proposal.String(), ErrNoDeal)
 	}

gen/main.go

@@ -11,6 +11,7 @@ import (
 	"github.com/filecoin-project/lotus/chain/blocksync"
 	"github.com/filecoin-project/lotus/chain/deals"
 	"github.com/filecoin-project/lotus/chain/types"
+	"github.com/filecoin-project/lotus/lib/evtsm"
 	"github.com/filecoin-project/lotus/paych"
 	"github.com/filecoin-project/lotus/retrieval"
 	"github.com/filecoin-project/lotus/storage"
@@ -164,4 +165,13 @@ func main() {
 		fmt.Println(err)
 		os.Exit(1)
 	}
+
+	err = gen.WriteMapEncodersToFile("./lib/evtsm/cbor_gen.go", "evtsm",
+		evtsm.TestState{},
+		evtsm.TestEvent{},
+	)
+	if err != nil {
+		fmt.Printf("%+v\n", err)
+		os.Exit(1)
+	}
 }

go.mod

@@ -103,6 +103,7 @@ require (
 	golang.org/x/crypto v0.0.0-20191206172530-e9b2fee46413 // indirect
 	golang.org/x/sys v0.0.0-20191210023423-ac6580df4449 // indirect
 	golang.org/x/time v0.0.0-20190308202827-9d24e82272b4
+	golang.org/x/tools v0.0.0-20191029190741-b9c20aec41a5
 	golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543
 	gopkg.in/cheggaaa/pb.v1 v1.0.28
 	gopkg.in/urfave/cli.v2 v2.0.0-20180128182452-d3ae77c26ac8
@@ -113,3 +114,7 @@ require (
 replace github.com/golangci/golangci-lint => github.com/golangci/golangci-lint v1.18.0
 
 replace github.com/filecoin-project/filecoin-ffi => ./extern/filecoin-ffi
+
+replace github.com/whyrusleeping/cbor-gen => /home/magik6k/gohack/github.com/whyrusleeping/cbor-gen
+
+replace github.com/filecoin-project/go-cbor-util => /home/magik6k/gohack/github.com/filecoin-project/go-cbor-util

go.sum

@@ -85,12 +85,10 @@ github.com/filecoin-project/go-address v0.0.0-20191219011437-af739c490b4f h1:L2j
 github.com/filecoin-project/go-address v0.0.0-20191219011437-af739c490b4f/go.mod h1:rCbpXPva2NKF9/J4X6sr7hbKBgQCxyFtRj7KOZqoIms=
 github.com/filecoin-project/go-amt-ipld v0.0.0-20191205011053-79efc22d6cdc h1:cODZD2YzpTUtrOSxbEnWFcQHidNRZiRdvLxySjGvG/M=
 github.com/filecoin-project/go-amt-ipld v0.0.0-20191205011053-79efc22d6cdc/go.mod h1:KsFPWjF+UUYl6n9A+qbg4bjFgAOneicFZtDH/LQEX2U=
-github.com/filecoin-project/go-paramfetch v0.0.0-20200102181131-b20d579f2878 h1:YicJT9xhPzZ1SBGiJFNUCkfwqK/G9vFyY1ytKBSjNJA=
-github.com/filecoin-project/go-paramfetch v0.0.0-20200102181131-b20d579f2878/go.mod h1:40kI2Gv16mwcRsHptI3OAV4nlOEU7wVDc4RgMylNFjU=
 github.com/filecoin-project/go-crypto v0.0.0-20191218222705-effae4ea9f03 h1:2pMXdBnCiXjfCYx/hLqFxccPoqsSveQFxVLvNxy9bus=
 github.com/filecoin-project/go-crypto v0.0.0-20191218222705-effae4ea9f03/go.mod h1:+viYnvGtUTgJRdy6oaeF4MTFKAfatX071MPDPBL11EQ=
-github.com/filecoin-project/go-cbor-util v0.0.0-20191219014500-08c40a1e63a2 h1:av5fw6wmm58FYMgJeoB/lK9XXrgdugYiTqkdxjTy9k8=
-github.com/filecoin-project/go-cbor-util v0.0.0-20191219014500-08c40a1e63a2/go.mod h1:pqTiPHobNkOVM5thSRsHYjyQfq7O5QSCMhvuu9JoDlg=
+github.com/filecoin-project/go-paramfetch v0.0.0-20200102181131-b20d579f2878 h1:YicJT9xhPzZ1SBGiJFNUCkfwqK/G9vFyY1ytKBSjNJA=
+github.com/filecoin-project/go-paramfetch v0.0.0-20200102181131-b20d579f2878/go.mod h1:40kI2Gv16mwcRsHptI3OAV4nlOEU7wVDc4RgMylNFjU=
 github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV9I=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
 github.com/gbrlsnchs/jwt/v3 v3.0.0-beta.1 h1:EzDjxMg43q1tA2c0MV3tNbaontnHLplHyFF6M5KiVP0=
@@ -629,11 +627,6 @@ github.com/whyrusleeping/base32 v0.0.0-20170828182744-c30ac30633cc h1:BCPnHtcboa
 github.com/whyrusleeping/base32 v0.0.0-20170828182744-c30ac30633cc/go.mod h1:r45hJU7yEoA81k6MWNhpMj/kms0n14dkzkxYHoB96UM=
 github.com/whyrusleeping/bencher v0.0.0-20190829221104-bb6607aa8bba h1:X4n8JG2e2biEZZXdBKt9HX7DN3bYGFUqljqqy0DqgnY=
 github.com/whyrusleeping/bencher v0.0.0-20190829221104-bb6607aa8bba/go.mod h1:CHQnYnQUEPydYCwuy8lmTHfGmdw9TKrhWV0xLx8l0oM=
-github.com/whyrusleeping/cbor-gen v0.0.0-20190910031516-c1cbffdb01bb/go.mod h1:xdlJQaiqipF0HW+Mzpg7XRM3fWbGvfgFlcppuvlkIvY=
-github.com/whyrusleeping/cbor-gen v0.0.0-20190917003517-d78d67427694/go.mod h1:xdlJQaiqipF0HW+Mzpg7XRM3fWbGvfgFlcppuvlkIvY=
-github.com/whyrusleeping/cbor-gen v0.0.0-20191116002219-891f55cd449d/go.mod h1:xdlJQaiqipF0HW+Mzpg7XRM3fWbGvfgFlcppuvlkIvY=
-github.com/whyrusleeping/cbor-gen v0.0.0-20191216205031-b047b6acb3c0 h1:efb/4CnrubzNGqQOeHErxyQ6rIsJb7GcgeSDF7fqWeI=
-github.com/whyrusleeping/cbor-gen v0.0.0-20191216205031-b047b6acb3c0/go.mod h1:xdlJQaiqipF0HW+Mzpg7XRM3fWbGvfgFlcppuvlkIvY=
 github.com/whyrusleeping/chunker v0.0.0-20181014151217-fe64bd25879f h1:jQa4QT2UP9WYv2nzyawpKMOCl+Z/jW7djv2/J50lj9E=
 github.com/whyrusleeping/chunker v0.0.0-20181014151217-fe64bd25879f/go.mod h1:p9UJB6dDgdPgMJZs7UjUOdulKyRr9fqkS+6JKAInPy8=
 github.com/whyrusleeping/go-keyspace v0.0.0-20160322163242-5b898ac5add1 h1:EKhdznlJHPMoKr0XTrX+IlJs1LH3lyx2nfr1dOlZ79k=

lib/evtsm/cbor_gen.go

@@ -0,0 +1,238 @@
+package evtsm
+
+import (
+	"fmt"
+	"io"
+
+	cbg "github.com/whyrusleeping/cbor-gen"
+	xerrors "golang.org/x/xerrors"
+)
+
+// Code generated by github.com/whyrusleeping/cbor-gen. DO NOT EDIT.
+
+var _ = xerrors.Errorf
+
+func (t *TestState) MarshalCBOR(w io.Writer) error {
+	if t == nil {
+		_, err := w.Write(cbg.CborNull)
+		return err
+	}
+	if _, err := w.Write([]byte{162}); err != nil {
+		return err
+	}
+
+	// t.A (uint64) (uint64)
+	if len("A") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"A\" was too long")
+	}
+
+	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("A")))); err != nil {
+		return err
+	}
+	if _, err := w.Write([]byte("A")); err != nil {
+		return err
+	}
+
+	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajUnsignedInt, uint64(t.A))); err != nil {
+		return err
+	}
+
+	// t.B (uint64) (uint64)
+	if len("B") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"B\" was too long")
+	}
+
+	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("B")))); err != nil {
+		return err
+	}
+	if _, err := w.Write([]byte("B")); err != nil {
+		return err
+	}
+
+	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajUnsignedInt, uint64(t.B))); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (t *TestState) UnmarshalCBOR(r io.Reader) error {
+	br := cbg.GetPeeker(r)
+
+	maj, extra, err := cbg.CborReadHeader(br)
+	if err != nil {
+		return err
+	}
+	if maj != cbg.MajMap {
+		return fmt.Errorf("cbor input should be of type map")
+	}
+
+	if extra != 2 {
+		return fmt.Errorf("cbor input had wrong number of fields")
+	}
+
+	var name string
+
+	// t.A (uint64) (uint64)
+
+	{
+		sval, err := cbg.ReadString(br)
+		if err != nil {
+			return err
+		}
+
+		name = string(sval)
+	}
+
+	if name != "A" {
+		return fmt.Errorf("expected struct map entry %s to be A", name)
+	}
+
+	maj, extra, err = cbg.CborReadHeader(br)
+	if err != nil {
+		return err
+	}
+	if maj != cbg.MajUnsignedInt {
+		return fmt.Errorf("wrong type for uint64 field")
+	}
+	t.A = uint64(extra)
+	// t.B (uint64) (uint64)
+
+	{
+		sval, err := cbg.ReadString(br)
+		if err != nil {
+			return err
+		}
+
+		name = string(sval)
+	}
+
+	if name != "B" {
+		return fmt.Errorf("expected struct map entry %s to be B", name)
+	}
+
+	maj, extra, err = cbg.CborReadHeader(br)
+	if err != nil {
+		return err
+	}
+	if maj != cbg.MajUnsignedInt {
+		return fmt.Errorf("wrong type for uint64 field")
+	}
+	t.B = uint64(extra)
+	return nil
+}
+
+func (t *TestEvent) MarshalCBOR(w io.Writer) error {
+	if t == nil {
+		_, err := w.Write(cbg.CborNull)
+		return err
+	}
+	if _, err := w.Write([]byte{162}); err != nil {
+		return err
+	}
+
+	// t.A (string) (string)
+	if len("A") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"A\" was too long")
+	}
+
+	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("A")))); err != nil {
+		return err
+	}
+	if _, err := w.Write([]byte("A")); err != nil {
+		return err
+	}
+
+	if len(t.A) > cbg.MaxLength {
+		return xerrors.Errorf("Value in field t.A was too long")
+	}
+
+	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len(t.A)))); err != nil {
+		return err
+	}
+	if _, err := w.Write([]byte(t.A)); err != nil {
+		return err
+	}
+
+	// t.Val (uint64) (uint64)
+	if len("Val") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"Val\" was too long")
+	}
+
+	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("Val")))); err != nil {
+		return err
+	}
+	if _, err := w.Write([]byte("Val")); err != nil {
+		return err
+	}
+
+	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajUnsignedInt, uint64(t.Val))); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (t *TestEvent) UnmarshalCBOR(r io.Reader) error {
+	br := cbg.GetPeeker(r)
+
+	maj, extra, err := cbg.CborReadHeader(br)
+	if err != nil {
+		return err
+	}
+	if maj != cbg.MajMap {
+		return fmt.Errorf("cbor input should be of type map")
+	}
+
+	if extra != 2 {
+		return fmt.Errorf("cbor input had wrong number of fields")
+	}
+
+	var name string
+
+	// t.A (string) (string)
+
+	{
+		sval, err := cbg.ReadString(br)
+		if err != nil {
+			return err
+		}
+
+		name = string(sval)
+	}
+
+	if name != "A" {
+		return fmt.Errorf("expected struct map entry %s to be A", name)
+	}
+
+	{
+		sval, err := cbg.ReadString(br)
+		if err != nil {
+			return err
+		}
+
+		t.A = string(sval)
+	}
+	// t.Val (uint64) (uint64)
+
+	{
+		sval, err := cbg.ReadString(br)
+		if err != nil {
+			return err
+		}
+
+		name = string(sval)
+	}
+
+	if name != "Val" {
+		return fmt.Errorf("expected struct map entry %s to be Val", name)
+	}
+
+	maj, extra, err = cbg.CborReadHeader(br)
+	if err != nil {
+		return err
+	}
+	if maj != cbg.MajUnsignedInt {
+		return fmt.Errorf("wrong type for uint64 field")
+	}
+	t.Val = uint64(extra)
+	return nil
+}

lib/evtsm/ctx.go

@@ -0,0 +1,16 @@
+package evtsm
+
+import "context"
+
+type Context struct {
+	ctx  context.Context
+	send func(evt interface{}) error
+}
+
+func (ctx *Context) Context() context.Context {
+	return ctx.ctx
+}
+
+func (ctx *Context) Send(evt interface{}) error {
+	return ctx.send(evt)
+}

lib/evtsm/event.go

@@ -0,0 +1,5 @@
+package evtsm
+
+type Event struct {
+	User interface{}
+}

lib/evtsm/evtsm.go

@@ -0,0 +1,120 @@
+package evtsm
+
+import (
+	"context"
+	"reflect"
+	"sync/atomic"
+
+	"github.com/filecoin-project/lotus/lib/statestore"
+	logging "github.com/ipfs/go-log"
+)
+
+var log = logging.Logger("evtsm")
+
+// returns func(ctx Context, st <T>) (func(*<T>), error), where <T> is the typeOf(User) param
+type Planner func(events []Event, user interface{}) (interface{}, error)
+
+type ESm struct {
+	planner  Planner
+	eventsIn chan Event
+
+	name      interface{}
+	st        *statestore.StoredState
+	stateType reflect.Type
+
+	stageDone chan struct{}
+	closing   chan struct{}
+	closed    chan struct{}
+
+	busy int32
+}
+
+func (fsm *ESm) run() {
+	defer close(fsm.closed)
+
+	var pendingEvents []Event
+
+	for {
+		// NOTE: This requires at least one event to be sent to trigger a stage
+		//  This means that after restarting the state machine users of this
+		//  code must send a 'restart' event
+		select {
+		case evt := <-fsm.eventsIn:
+			pendingEvents = append(pendingEvents, evt)
+		case <-fsm.stageDone:
+			if len(pendingEvents) == 0 {
+				continue
+			}
+		case <-fsm.closing:
+			return
+		}
+
+		if atomic.CompareAndSwapInt32(&fsm.busy, 0, 1) {
+			var nextStep interface{}
+			var ustate interface{}
+
+			err := fsm.mutateUser(func(user interface{}) (err error) {
+				nextStep, err = fsm.planner(pendingEvents, user)
+				ustate = user
+				return err
+			})
+			if err != nil {
+				log.Errorf("Executing event planner failed: %+v", err)
+				return
+			}
+
+			pendingEvents = nil
+
+			if nextStep == nil {
+				continue
+			}
+
+			ctx := Context{
+				ctx: context.TODO(),
+				send: func(evt interface{}) error {
+					return fsm.send(Event{User: evt})
+				},
+			}
+
+			go func() {
+				res := reflect.ValueOf(nextStep).Call([]reflect.Value{reflect.ValueOf(ctx), reflect.ValueOf(ustate).Elem()})
+
+				if res[0].Interface() != nil {
+					log.Errorf("executing step: %+v", res[0].Interface().(error)) // TODO: propagate top level
+					return
+				}
+
+				atomic.StoreInt32(&fsm.busy, 0)
+				fsm.stageDone <- struct{}{}
+			}()
+
+		}
+	}
+}
+
+func (fsm *ESm) mutateUser(cb func(user interface{}) error) error {
+	mutt := reflect.FuncOf([]reflect.Type{reflect.PtrTo(fsm.stateType)}, []reflect.Type{reflect.TypeOf(new(error)).Elem()}, false)
+
+	mutf := reflect.MakeFunc(mutt, func(args []reflect.Value) (results []reflect.Value) {
+		err := cb(args[0].Interface())
+		return []reflect.Value{reflect.ValueOf(&err).Elem()}
+	})
+
+	return fsm.st.Mutate(mutf.Interface())
+}
+
+func (fsm *ESm) send(evt Event) error {
+	fsm.eventsIn <- evt // TODO: ctx, at least
+	return nil
+}
+
+func (fsm *ESm) stop(ctx context.Context) error {
+	close(fsm.closing)
+
+	select {
+	case <-fsm.closed:
+		return nil
+	case <-ctx.Done():
+		return ctx.Err()
+	}
+}

lib/evtsm/evtsm_test.go

@@ -0,0 +1,106 @@
+package evtsm
+
+import (
+	"context"
+	"reflect"
+	"testing"
+
+	"github.com/ipfs/go-datastore"
+	logging "github.com/ipfs/go-log"
+	"gotest.tools/assert"
+)
+
+func init() {
+	logging.SetLogLevel("*", "INFO")
+}
+
+type testHandler struct {
+	t       *testing.T
+	proceed chan struct{}
+	done    chan struct{}
+}
+
+func (t *testHandler) Plan(events []Event, state interface{}) (interface{}, error) {
+	return t.plan(events, state.(*TestState))
+}
+
+func (t *testHandler) plan(events []Event, state *TestState) (interface{}, error) {
+	for _, event := range events {
+		e := event.User.(*TestEvent)
+		switch e.A {
+		case "restart":
+		case "start":
+			state.A = 1
+		case "b":
+			state.A = 2
+			state.B = e.Val
+		}
+	}
+
+	switch state.A {
+	case 1:
+		return t.step0, nil
+	case 2:
+		return t.step1, nil
+	default:
+		t.t.Fatal(state.A)
+	}
+	panic("how?")
+}
+
+func (t *testHandler) step0(ctx Context, st TestState) error {
+	ctx.Send(&TestEvent{A: "b", Val: 55})
+	<-t.proceed
+	return nil
+}
+
+func (t *testHandler) step1(ctx Context, st TestState) error {
+	assert.Equal(t.t, uint64(2), st.A)
+
+	close(t.done)
+	return nil
+}
+
+func TestBasic(t *testing.T) {
+	for i := 0; i < 1000; i++ { // run a few times to expose any races
+		ds := datastore.NewMapDatastore()
+
+		th := &testHandler{t: t, done: make(chan struct{}), proceed: make(chan struct{})}
+		close(th.proceed)
+		smm := New(ds, th, reflect.TypeOf(TestState{}))
+
+		if err := smm.Send(uint64(2), &TestEvent{A: "start"}); err != nil {
+			t.Fatalf("%+v", err)
+		}
+
+		<-th.done
+	}
+}
+
+func TestPersist(t *testing.T) {
+	for i := 0; i < 1000; i++ { // run a few times to expose any races
+		ds := datastore.NewMapDatastore()
+
+		th := &testHandler{t: t, done: make(chan struct{}), proceed: make(chan struct{})}
+		smm := New(ds, th, reflect.TypeOf(TestState{}))
+
+		if err := smm.Send(uint64(2), &TestEvent{A: "start"}); err != nil {
+			t.Fatalf("%+v", err)
+		}
+
+		if err := smm.Stop(context.Background()); err != nil {
+			t.Fatal(err)
+			return
+		}
+
+		smm = New(ds, th, reflect.TypeOf(TestState{}))
+		if err := smm.Send(uint64(2), &TestEvent{A: "restart"}); err != nil {
+			t.Fatalf("%+v", err)
+		}
+		close(th.proceed)
+
+		<-th.done
+	}
+}
+
+var _ StateHandler = &testHandler{}

lib/evtsm/sched.go

@@ -0,0 +1,99 @@
+package evtsm
+
+import (
+	"context"
+	"reflect"
+	"sync"
+
+	"github.com/ipfs/go-datastore"
+	"golang.org/x/xerrors"
+
+	"github.com/filecoin-project/lotus/lib/statestore"
+)
+
+type StateHandler interface {
+	// returns
+	Plan(events []Event, user interface{}) (interface{}, error)
+}
+
+type Sched struct {
+	sts       *statestore.StateStore
+	hnd       StateHandler
+	stateType reflect.Type
+
+	lk  sync.Mutex
+	sms map[datastore.Key]*ESm
+}
+
+// stateType: T - (reflect.TypeOf(MyStateStruct{}))
+func New(ds datastore.Datastore, hnd StateHandler, stateType reflect.Type) *Sched {
+	return &Sched{
+		sts:       statestore.New(ds),
+		hnd:       hnd,
+		stateType: stateType,
+
+		sms: map[datastore.Key]*ESm{},
+	}
+}
+
+func (s *Sched) Send(to interface{}, evt interface{}) (err error) {
+	s.lk.Lock()
+	defer s.lk.Unlock()
+
+	sm, exist := s.sms[statestore.ToKey(to)]
+	if !exist {
+		sm, err = s.loadOrCreate(to)
+		if err != nil {
+			return xerrors.Errorf("loadOrCreate state: %w", err)
+		}
+		s.sms[statestore.ToKey(to)] = sm
+	}
+
+	return sm.send(Event{User: evt})
+}
+
+func (s *Sched) loadOrCreate(name interface{}) (*ESm, error) {
+	exists, err := s.sts.Has(name)
+	if err != nil {
+		return nil, xerrors.Errorf("failed to check if state for %v exists: %w", name, err)
+	}
+
+	if !exists {
+		userState := reflect.New(s.stateType).Interface()
+
+		err = s.sts.Begin(name, userState)
+		if err != nil {
+			return nil, xerrors.Errorf("saving initial state: %w", err)
+		}
+	}
+
+	res := &ESm{
+		planner:  s.hnd.Plan,
+		eventsIn: make(chan Event),
+
+		name:      name,
+		st:        s.sts.Get(name),
+		stateType: s.stateType,
+
+		stageDone: make(chan struct{}),
+		closing:   make(chan struct{}),
+		closed:    make(chan struct{}),
+	}
+
+	go res.run()
+
+	return res, nil
+}
+
+func (s *Sched) Stop(ctx context.Context) error {
+	s.lk.Lock()
+	defer s.lk.Unlock()
+
+	for _, sm := range s.sms {
+		if err := sm.stop(ctx); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}

lib/evtsm/testing.go

@@ -0,0 +1,11 @@
+package evtsm
+
+type TestState struct {
+	A uint64
+	B uint64
+}
+
+type TestEvent struct {
+	A   string
+	Val uint64
+}

lib/statestore/state.go

@@ -0,0 +1,93 @@
+package statestore
+
+import (
+	"bytes"
+	"reflect"
+
+	cborutil "github.com/filecoin-project/go-cbor-util"
+	"github.com/ipfs/go-datastore"
+	cbg "github.com/whyrusleeping/cbor-gen"
+	"golang.org/x/xerrors"
+)
+
+type StoredState struct {
+	ds   datastore.Datastore
+	name datastore.Key
+}
+
+func (st *StoredState) End() error {
+	has, err := st.ds.Has(st.name)
+	if err != nil {
+		return err
+	}
+	if !has {
+		return xerrors.Errorf("No state for %s", st.name)
+	}
+	if err := st.ds.Delete(st.name); err != nil {
+		return xerrors.Errorf("removing state from datastore: %w", err)
+	}
+	st.name = datastore.Key{}
+	st.ds = nil
+
+	return nil
+}
+
+func (st *StoredState) Get(out cbg.CBORUnmarshaler) error {
+	val, err := st.ds.Get(st.name)
+	if err != nil {
+		if xerrors.Is(err, datastore.ErrNotFound) {
+			return xerrors.Errorf("No state for %s: %w", st.name, err)
+		}
+		return err
+	}
+
+	return out.UnmarshalCBOR(bytes.NewReader(val))
+}
+
+// mutator func(*T) error
+func (st *StoredState) Mutate(mutator interface{}) error {
+	return st.mutate(cborMutator(mutator))
+}
+
+func (st *StoredState) mutate(mutator func([]byte) ([]byte, error)) error {
+	has, err := st.ds.Has(st.name)
+	if err != nil {
+		return err
+	}
+	if !has {
+		return xerrors.Errorf("No state for %s", st.name)
+	}
+
+	cur, err := st.ds.Get(st.name)
+	if err != nil {
+		return err
+	}
+
+	mutated, err := mutator(cur)
+	if err != nil {
+		return err
+	}
+
+	return st.ds.Put(st.name, mutated)
+}
+
+func cborMutator(mutator interface{}) func([]byte) ([]byte, error) {
+	rmut := reflect.ValueOf(mutator)
+
+	return func(in []byte) ([]byte, error) {
+		state := reflect.New(rmut.Type().In(0).Elem())
+
+		err := cborutil.ReadCborRPC(bytes.NewReader(in), state.Interface())
+		if err != nil {
+			return nil, err
+		}
+
+		out := rmut.Call([]reflect.Value{state})
+
+		if err := out[0].Interface(); err != nil {
+			return nil, err.(error)
+		}
+
+		return cborutil.Dump(state.Interface())
+	}
+}

lib/statestore/store.go

@@ -5,13 +5,11 @@ import (
 	"fmt"
 	"reflect"
 
+	"github.com/filecoin-project/go-cbor-util"
 	"github.com/ipfs/go-datastore"
 	"github.com/ipfs/go-datastore/query"
-	cbg "github.com/whyrusleeping/cbor-gen"
 	"go.uber.org/multierr"
 	"golang.org/x/xerrors"
-
-	"github.com/filecoin-project/go-cbor-util"
 )
 
 type StateStore struct {
@@ -22,7 +20,7 @@ func New(ds datastore.Datastore) *StateStore {
 	return &StateStore{ds: ds}
 }
 
-func toKey(k interface{}) datastore.Key {
+func ToKey(k interface{}) datastore.Key {
 	switch t := k.(type) {
 	case uint64:
 		return datastore.NewKey(fmt.Sprint(t))
@@ -34,7 +32,7 @@ func toKey(k interface{}) datastore.Key {
 }
 
 func (st *StateStore) Begin(i interface{}, state interface{}) error {
-	k := toKey(i)
+	k := ToKey(i)
 	has, err := st.ds.Has(k)
 	if err != nil {
 		return err
@@ -51,82 +49,15 @@ func (st *StateStore) Begin(i interface{}, state interface{}) error {
 	return st.ds.Put(k, b)
 }
 
-func (st *StateStore) End(i interface{}) error {
-	k := toKey(i)
-	has, err := st.ds.Has(k)
-	if err != nil {
-		return err
+func (st *StateStore) Get(i interface{}) *StoredState {
+	return &StoredState{
+		ds:   st.ds,
+		name: ToKey(i),
 	}
-	if !has {
-		return xerrors.Errorf("No state for %s", i)
-	}
-	return st.ds.Delete(k)
-}
-
-func cborMutator(mutator interface{}) func([]byte) ([]byte, error) {
-	rmut := reflect.ValueOf(mutator)
-
-	return func(in []byte) ([]byte, error) {
-		state := reflect.New(rmut.Type().In(0).Elem())
-
-		err := cborutil.ReadCborRPC(bytes.NewReader(in), state.Interface())
-		if err != nil {
-			return nil, err
-		}
-
-		out := rmut.Call([]reflect.Value{state})
-
-		if err := out[0].Interface(); err != nil {
-			return nil, err.(error)
-		}
-
-		return cborutil.Dump(state.Interface())
-	}
-}
-
-// mutator func(*T) error
-func (st *StateStore) Mutate(i interface{}, mutator interface{}) error {
-	return st.mutate(i, cborMutator(mutator))
-}
-
-func (st *StateStore) mutate(i interface{}, mutator func([]byte) ([]byte, error)) error {
-	k := toKey(i)
-	has, err := st.ds.Has(k)
-	if err != nil {
-		return err
-	}
-	if !has {
-		return xerrors.Errorf("No state for %s", i)
-	}
-
-	cur, err := st.ds.Get(k)
-	if err != nil {
-		return err
-	}
-
-	mutated, err := mutator(cur)
-	if err != nil {
-		return err
-	}
-
-	return st.ds.Put(k, mutated)
 }
 
 func (st *StateStore) Has(i interface{}) (bool, error) {
-	return st.ds.Has(toKey(i))
-}
-
-func (st *StateStore) Get(i interface{}, out cbg.CBORUnmarshaler) error {
-	k := toKey(i)
-	val, err := st.ds.Get(k)
-	if err != nil {
-		if xerrors.Is(err, datastore.ErrNotFound) {
-			return xerrors.Errorf("No state for %s: %w", i, err)
-		}
-		return err
-	}
-
-	return out.UnmarshalCBOR(bytes.NewReader(val))
+	return st.ds.Has(ToKey(i))
 }
 
 // out: *[]T

storage/cbor_gen.go

@@ -22,6 +22,10 @@ func (t *SealTicket) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.BlockHeight (uint64) (uint64)
+	if len("BlockHeight") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"BlockHeight\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("BlockHeight")))); err != nil {
 		return err
 	}
@@ -34,6 +38,10 @@ func (t *SealTicket) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.TicketBytes ([]uint8) (slice)
+	if len("TicketBytes") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"TicketBytes\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("TicketBytes")))); err != nil {
 		return err
 	}
@@ -41,6 +49,10 @@ func (t *SealTicket) MarshalCBOR(w io.Writer) error {
 		return err
 	}
 
+	if len(t.TicketBytes) > cbg.ByteArrayMaxLen {
+		return xerrors.Errorf("Byte array in field t.TicketBytes was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajByteString, uint64(len(t.TicketBytes)))); err != nil {
 		return err
 	}
@@ -133,6 +145,10 @@ func (t *SealSeed) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.BlockHeight (uint64) (uint64)
+	if len("BlockHeight") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"BlockHeight\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("BlockHeight")))); err != nil {
 		return err
 	}
@@ -145,6 +161,10 @@ func (t *SealSeed) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.TicketBytes ([]uint8) (slice)
+	if len("TicketBytes") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"TicketBytes\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("TicketBytes")))); err != nil {
 		return err
 	}
@@ -152,6 +172,10 @@ func (t *SealSeed) MarshalCBOR(w io.Writer) error {
 		return err
 	}
 
+	if len(t.TicketBytes) > cbg.ByteArrayMaxLen {
+		return xerrors.Errorf("Byte array in field t.TicketBytes was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajByteString, uint64(len(t.TicketBytes)))); err != nil {
 		return err
 	}
@@ -244,6 +268,10 @@ func (t *Piece) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.DealID (uint64) (uint64)
+	if len("DealID") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"DealID\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("DealID")))); err != nil {
 		return err
 	}
@@ -256,6 +284,10 @@ func (t *Piece) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.Size (uint64) (uint64)
+	if len("Size") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"Size\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("Size")))); err != nil {
 		return err
 	}
@@ -268,6 +300,10 @@ func (t *Piece) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.CommP ([]uint8) (slice)
+	if len("CommP") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"CommP\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("CommP")))); err != nil {
 		return err
 	}
@@ -275,6 +311,10 @@ func (t *Piece) MarshalCBOR(w io.Writer) error {
 		return err
 	}
 
+	if len(t.CommP) > cbg.ByteArrayMaxLen {
+		return xerrors.Errorf("Byte array in field t.CommP was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajByteString, uint64(len(t.CommP)))); err != nil {
 		return err
 	}
@@ -390,6 +430,10 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.State (uint64) (uint64)
+	if len("State") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"State\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("State")))); err != nil {
 		return err
 	}
@@ -402,6 +446,10 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.SectorID (uint64) (uint64)
+	if len("SectorID") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"SectorID\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("SectorID")))); err != nil {
 		return err
 	}
@@ -414,6 +462,10 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.Nonce (uint64) (uint64)
+	if len("Nonce") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"Nonce\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("Nonce")))); err != nil {
 		return err
 	}
@@ -426,6 +478,10 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.Pieces ([]storage.Piece) (slice)
+	if len("Pieces") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"Pieces\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("Pieces")))); err != nil {
 		return err
 	}
@@ -433,6 +489,10 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 		return err
 	}
 
+	if len(t.Pieces) > cbg.MaxLength {
+		return xerrors.Errorf("Slice value in field t.Pieces was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajArray, uint64(len(t.Pieces)))); err != nil {
 		return err
 	}
@@ -443,6 +503,10 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.CommD ([]uint8) (slice)
+	if len("CommD") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"CommD\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("CommD")))); err != nil {
 		return err
 	}
@@ -450,6 +514,10 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 		return err
 	}
 
+	if len(t.CommD) > cbg.ByteArrayMaxLen {
+		return xerrors.Errorf("Byte array in field t.CommD was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajByteString, uint64(len(t.CommD)))); err != nil {
 		return err
 	}
@@ -458,6 +526,10 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.CommR ([]uint8) (slice)
+	if len("CommR") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"CommR\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("CommR")))); err != nil {
 		return err
 	}
@@ -465,6 +537,10 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 		return err
 	}
 
+	if len(t.CommR) > cbg.ByteArrayMaxLen {
+		return xerrors.Errorf("Byte array in field t.CommR was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajByteString, uint64(len(t.CommR)))); err != nil {
 		return err
 	}
@@ -473,6 +549,10 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.Proof ([]uint8) (slice)
+	if len("Proof") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"Proof\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("Proof")))); err != nil {
 		return err
 	}
@@ -480,6 +560,10 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 		return err
 	}
 
+	if len(t.Proof) > cbg.ByteArrayMaxLen {
+		return xerrors.Errorf("Byte array in field t.Proof was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajByteString, uint64(len(t.Proof)))); err != nil {
 		return err
 	}
@@ -488,6 +572,10 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.Ticket (storage.SealTicket) (struct)
+	if len("Ticket") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"Ticket\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("Ticket")))); err != nil {
 		return err
 	}
@@ -500,6 +588,10 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.PreCommitMessage (cid.Cid) (struct)
+	if len("PreCommitMessage") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"PreCommitMessage\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("PreCommitMessage")))); err != nil {
 		return err
 	}
@@ -518,6 +610,10 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.Seed (storage.SealSeed) (struct)
+	if len("Seed") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"Seed\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("Seed")))); err != nil {
 		return err
 	}
@@ -530,6 +626,10 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.CommitMessage (cid.Cid) (struct)
+	if len("CommitMessage") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"CommitMessage\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("CommitMessage")))); err != nil {
 		return err
 	}
@@ -548,6 +648,10 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.FaultReportMsg (cid.Cid) (struct)
+	if len("FaultReportMsg") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"FaultReportMsg\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("FaultReportMsg")))); err != nil {
 		return err
 	}
@@ -566,6 +670,10 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 	}
 
 	// t.LastErr (string) (string)
+	if len("LastErr") > cbg.MaxLength {
+		return xerrors.Errorf("Value in field \"LastErr\" was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len("LastErr")))); err != nil {
 		return err
 	}
@@ -573,6 +681,10 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 		return err
 	}
 
+	if len(t.LastErr) > cbg.MaxLength {
+		return xerrors.Errorf("Value in field t.LastErr was too long")
+	}
+
 	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajTextString, uint64(len(t.LastErr)))); err != nil {
 		return err
 	}

storage/sector_utils.go

@@ -52,6 +52,6 @@ func (m *Miner) ListSectors() ([]SectorInfo, error) {
 
 func (m *Miner) GetSectorInfo(sid uint64) (SectorInfo, error) {
 	var out SectorInfo
-	err := m.sectors.Get(sid, &out)
+	err := m.sectors.Get(sid).Get(&out)
 	return out, err
 }

storage/sectors.go

@@ -161,7 +161,7 @@ func (m *Miner) onSectorIncoming(sector *SectorInfo) {
 func (m *Miner) onSectorUpdated(ctx context.Context, update sectorUpdate) {
 	log.Infof("Sector %d updated state to %s", update.id, api.SectorStates[update.newState])
 	var sector SectorInfo
-	err := m.sectors.Mutate(update.id, func(s *SectorInfo) error {
+	err := m.sectors.Get(update.id).Mutate(func(s *SectorInfo) error {
 		if update.nonce < s.Nonce {
 			return xerrors.Errorf("update nonce too low, ignoring (%d < %d)", update.nonce, s.Nonce)
 		}