event: deprecate TypeMux and related types

The Subscription type is gone, all uses are replaced by
*TypeMuxSubscription. This change is prep-work for the
introduction of the new Subscription type in a later commit.

   gorename -from '"github.com/ethereum/go-ethereum/event"::Event' -to TypeMuxEvent
   gorename -from '"github.com/ethereum/go-ethereum/event"::muxsub' -to TypeMuxSubscription
   gofmt -w -r 'Subscription -> *TypeMuxSubscription' ./event/*.go
   find . -name '*.go' -and -not -regex '\./vendor/.*' \| xargs gofmt -w -r 'event.Subscription -> *event.TypeMuxSubscription'

core/tx_pool.go

@@ -89,7 +89,7 @@ type TxPool struct {
 	gasLimit     func() *big.Int // The current gas limit function callback
 	minGasPrice  *big.Int
 	eventMux     *event.TypeMux
-	events       event.Subscription
+	events       *event.TypeMuxSubscription
 	localTx      *txSet
 	signer       types.Signer
 	mu           sync.RWMutex

eth/filters/filter_system.go

@@ -74,7 +74,7 @@ type subscription struct {
 // subscription which match the subscription criteria.
 type EventSystem struct {
 	mux       *event.TypeMux
-	sub       event.Subscription
+	sub       *event.TypeMuxSubscription
 	backend   Backend
 	lightMode bool
 	lastHead  *types.Header
@@ -277,7 +277,7 @@ func (es *EventSystem) SubscribePendingTxEvents(hashes chan common.Hash) *Subscr
 type filterIndex map[Type]map[rpc.ID]*subscription
 
 // broadcast event to filters that match criteria.
-func (es *EventSystem) broadcast(filters filterIndex, ev *event.Event) {
+func (es *EventSystem) broadcast(filters filterIndex, ev *event.TypeMuxEvent) {
 	if ev == nil {
 		return
 	}

eth/handler.go

@@ -78,8 +78,8 @@ type ProtocolManager struct {
 	SubProtocols []p2p.Protocol
 
 	eventMux      *event.TypeMux
-	txSub         event.Subscription
-	minedBlockSub event.Subscription
+	txSub         *event.TypeMuxSubscription
+	minedBlockSub *event.TypeMuxSubscription
 
 	// channels for fetcher, syncer, txsyncLoop
 	newPeerCh   chan *peer

event/event.go

@@ -25,33 +25,22 @@ import (
 	"time"
 )
 
-// Event is a time-tagged notification pushed to subscribers.
-type Event struct {
+// TypeMuxEvent is a time-tagged notification pushed to subscribers.
+type TypeMuxEvent struct {
 	Time time.Time
 	Data interface{}
 }
 
-// Subscription is implemented by event subscriptions.
-type Subscription interface {
-	// Chan returns a channel that carries events.
-	// Implementations should return the same channel
-	// for any subsequent calls to Chan.
-	Chan() <-chan *Event
-
-	// Unsubscribe stops delivery of events to a subscription.
-	// The event channel is closed.
-	// Unsubscribe can be called more than once.
-	Unsubscribe()
-}
-
 // A TypeMux dispatches events to registered receivers. Receivers can be
 // registered to handle events of certain type. Any operation
 // called after mux is stopped will return ErrMuxClosed.
 //
 // The zero value is ready to use.
+//
+// Deprecated: use Feed
 type TypeMux struct {
 	mutex   sync.RWMutex
-	subm    map[reflect.Type][]*muxsub
+	subm    map[reflect.Type][]*TypeMuxSubscription
 	stopped bool
 }
 
@@ -61,7 +50,7 @@ var ErrMuxClosed = errors.New("event: mux closed")
 // Subscribe creates a subscription for events of the given types. The
 // subscription's channel is closed when it is unsubscribed
 // or the mux is closed.
-func (mux *TypeMux) Subscribe(types ...interface{}) Subscription {
+func (mux *TypeMux) Subscribe(types ...interface{}) *TypeMuxSubscription {
 	sub := newsub(mux)
 	mux.mutex.Lock()
 	defer mux.mutex.Unlock()
@@ -72,7 +61,7 @@ func (mux *TypeMux) Subscribe(types ...interface{}) Subscription {
 		close(sub.postC)
 	} else {
 		if mux.subm == nil {
-			mux.subm = make(map[reflect.Type][]*muxsub)
+			mux.subm = make(map[reflect.Type][]*TypeMuxSubscription)
 		}
 		for _, t := range types {
 			rtyp := reflect.TypeOf(t)
@@ -80,7 +69,7 @@ func (mux *TypeMux) Subscribe(types ...interface{}) Subscription {
 			if find(oldsubs, sub) != -1 {
 				panic(fmt.Sprintf("event: duplicate type %s in Subscribe", rtyp))
 			}
-			subs := make([]*muxsub, len(oldsubs)+1)
+			subs := make([]*TypeMuxSubscription, len(oldsubs)+1)
 			copy(subs, oldsubs)
 			subs[len(oldsubs)] = sub
 			mux.subm[rtyp] = subs
@@ -92,7 +81,7 @@ func (mux *TypeMux) Subscribe(types ...interface{}) Subscription {
 // Post sends an event to all receivers registered for the given type.
 // It returns ErrMuxClosed if the mux has been stopped.
 func (mux *TypeMux) Post(ev interface{}) error {
-	event := &Event{
+	event := &TypeMuxEvent{
 		Time: time.Now(),
 		Data: ev,
 	}
@@ -125,7 +114,7 @@ func (mux *TypeMux) Stop() {
 	mux.mutex.Unlock()
 }
 
-func (mux *TypeMux) del(s *muxsub) {
+func (mux *TypeMux) del(s *TypeMuxSubscription) {
 	mux.mutex.Lock()
 	for typ, subs := range mux.subm {
 		if pos := find(subs, s); pos >= 0 {
@@ -139,7 +128,7 @@ func (mux *TypeMux) del(s *muxsub) {
 	s.mux.mutex.Unlock()
 }
 
-func find(slice []*muxsub, item *muxsub) int {
+func find(slice []*TypeMuxSubscription, item *TypeMuxSubscription) int {
 	for i, v := range slice {
 		if v == item {
 			return i
@@ -148,14 +137,15 @@ func find(slice []*muxsub, item *muxsub) int {
 	return -1
 }
 
-func posdelete(slice []*muxsub, pos int) []*muxsub {
-	news := make([]*muxsub, len(slice)-1)
+func posdelete(slice []*TypeMuxSubscription, pos int) []*TypeMuxSubscription {
+	news := make([]*TypeMuxSubscription, len(slice)-1)
 	copy(news[:pos], slice[:pos])
 	copy(news[pos:], slice[pos+1:])
 	return news
 }
 
-type muxsub struct {
+// TypeMuxSubscription is a subscription established through TypeMux.
+type TypeMuxSubscription struct {
 	mux     *TypeMux
 	created time.Time
 	closeMu sync.Mutex
@@ -166,13 +156,13 @@ type muxsub struct {
 	// postC can be set to nil without affecting the return value of
 	// Chan.
 	postMu sync.RWMutex
-	readC  <-chan *Event
-	postC  chan<- *Event
+	readC  <-chan *TypeMuxEvent
+	postC  chan<- *TypeMuxEvent
 }
 
-func newsub(mux *TypeMux) *muxsub {
-	c := make(chan *Event)
-	return &muxsub{
+func newsub(mux *TypeMux) *TypeMuxSubscription {
+	c := make(chan *TypeMuxEvent)
+	return &TypeMuxSubscription{
 		mux:     mux,
 		created: time.Now(),
 		readC:   c,
@@ -181,16 +171,16 @@ func newsub(mux *TypeMux) *muxsub {
 	}
 }
 
-func (s *muxsub) Chan() <-chan *Event {
+func (s *TypeMuxSubscription) Chan() <-chan *TypeMuxEvent {
 	return s.readC
 }
 
-func (s *muxsub) Unsubscribe() {
+func (s *TypeMuxSubscription) Unsubscribe() {
 	s.mux.del(s)
 	s.closewait()
 }
 
-func (s *muxsub) closewait() {
+func (s *TypeMuxSubscription) closewait() {
 	s.closeMu.Lock()
 	defer s.closeMu.Unlock()
 	if s.closed {
@@ -205,7 +195,7 @@ func (s *muxsub) closewait() {
 	s.postMu.Unlock()
 }
 
-func (s *muxsub) deliver(event *Event) {
+func (s *TypeMuxSubscription) deliver(event *TypeMuxEvent) {
 	// Short circuit delivery if stale event
 	if s.created.After(event.Time) {
 		return

light/txpool.go

@@ -47,7 +47,7 @@ type TxPool struct {
 	signer   types.Signer
 	quit     chan bool
 	eventMux *event.TypeMux
-	events   event.Subscription
+	events   *event.TypeMuxSubscription
 	mu       sync.RWMutex
 	chain    *LightChain
 	odr      OdrBackend

miner/worker.go

@@ -90,7 +90,7 @@ type worker struct {
 
 	// update loop
 	mux    *event.TypeMux
-	events event.Subscription
+	events *event.TypeMuxSubscription
 	wg     sync.WaitGroup
 
 	agents map[Agent]struct{}