Support wildcard subscriptions + getter for known types

basic.go

@@ -10,12 +10,14 @@ import (
 	"github.com/libp2p/go-libp2p-core/event"
 )
 
+var wildCardTypeElem = reflect.TypeOf(event.WildcardSubscriptionType).Elem()
+
 ///////////////////////
 // BUS
 
 // basicBus is a type-based event delivery system
 type basicBus struct {
-	lk    sync.Mutex
+	lk    sync.RWMutex
 	nodes map[reflect.Type]*node
 }
 
@@ -26,13 +28,24 @@ type emitter struct {
 	typ     reflect.Type
 	closed  int32
 	dropper func(reflect.Type)
+	b       *basicBus
 }
 
 func (e *emitter) Emit(evt interface{}) error {
 	if atomic.LoadInt32(&e.closed) != 0 {
 		return fmt.Errorf("emitter is closed")
 	}
 	e.n.emit(evt)
+
+	// emit on the wildcard subscription
+	e.b.lk.RLock()
+	n, ok := e.b.nodes[wildCardTypeElem]
+	e.b.lk.RUnlock()
+	if !ok {
+		return nil
+	}
+	n.emit(evt)
+
 	return nil
 }
 
@@ -216,11 +229,24 @@ func (b *basicBus) Emitter(evtType interface{}, opts ...event.EmitterOpt) (e eve
 	b.withNode(typ, func(n *node) {
 		atomic.AddInt32(&n.nEmitters, 1)
 		n.keepLast = n.keepLast || settings.makeStateful
-		e = &emitter{n: n, typ: typ, dropper: b.tryDropNode}
+		e = &emitter{n: n, typ: typ, dropper: b.tryDropNode, b: b}
 	}, nil)
 	return
 }
 
+// GetAllEventTypes returns all the event types that this bus has emitters
+// or subscribers for.
+func (b *basicBus) GetAllEventTypes() []reflect.Type {
+	b.lk.RLock()
+	defer b.lk.RUnlock()
+
+	types := make([]reflect.Type, 0, len(b.nodes))
+	for t, _ := range b.nodes {
+		types = append(types, t)
+	}
+	return types
+}
+
 ///////////////////////
 // NODE
 
@@ -245,19 +271,19 @@ func newNode(typ reflect.Type) *node {
 	}
 }
 
-func (n *node) emit(event interface{}) {
-	typ := reflect.TypeOf(event)
-	if typ != n.typ {
+func (n *node) emit(evt interface{}) {
+	typ := reflect.TypeOf(evt)
+	if typ != n.typ && n.typ != wildCardTypeElem {
 		panic(fmt.Sprintf("Emit called with wrong type. expected: %s, got: %s", n.typ, typ))
 	}
 
 	n.lk.Lock()
 	if n.keepLast {
-		n.last = event
+		n.last = evt
 	}
 
 	for _, ch := range n.sinks {
-		ch <- event
+		ch <- evt
 	}
 	n.lk.Unlock()
 }

basic_test.go

@@ -1,13 +1,18 @@
 package eventbus
 
 import (
+	"context"
 	"fmt"
+	"reflect"
 	"sync"
 	"sync/atomic"
 	"testing"
 	"time"
 
+	"github.com/libp2p/go-libp2p-core/event"
 	"github.com/libp2p/go-libp2p-testing/race"
+
+	"github.com/stretchr/testify/require"
 )
 
 type EventA struct{}
@@ -89,6 +94,26 @@ func TestSub(t *testing.T) {
 	}
 }
 
+func TestGetAllEventTypes(t *testing.T) {
+	bus := NewBus()
+	require.Empty(t, bus.GetAllEventTypes())
+
+	_, err := bus.Subscribe(new(EventB))
+	require.NoError(t, err)
+
+	evts := bus.GetAllEventTypes()
+	require.Len(t, evts, 1)
+	require.Equal(t, reflect.TypeOf((*EventB)(nil)).Elem(), evts[0])
+
+	_, err = bus.Emitter(new(EventA))
+	require.NoError(t, err)
+
+	evts = bus.GetAllEventTypes()
+	require.Len(t, evts, 2)
+	require.Contains(t, evts, reflect.TypeOf((*EventB)(nil)).Elem())
+	require.Contains(t, evts, reflect.TypeOf((*EventA)(nil)).Elem())
+}
+
 func TestEmitNoSubNoBlock(t *testing.T) {
 	bus := NewBus()
 
@@ -206,6 +231,50 @@ func TestSubMany(t *testing.T) {
 	}
 }
 
+func TestSubscribeAll(t *testing.T) {
+	bus := NewBus()
+	sub, err := bus.Subscribe(event.WildcardSubscriptionType)
+	require.NoError(t, err)
+	defer sub.Close()
+
+	em1, err := bus.Emitter(new(EventA))
+	require.NoError(t, err)
+	defer em1.Close()
+
+	em2, err := bus.Emitter(new(EventB))
+	require.NoError(t, err)
+	defer em2.Close()
+
+	require.NoError(t, em1.Emit(EventA{}))
+	require.NoError(t, em2.Emit(EventB(1)))
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	var evts []interface{}
+
+LOOP:
+	for {
+		select {
+		case evt := <-sub.Out():
+			if evta, ok := evt.(EventA); ok {
+				evts = append(evts, evta)
+			}
+
+			if evtb, ok := evt.(EventB); ok {
+				evts = append(evts, evtb)
+			}
+
+			if len(evts) == 2 {
+				break LOOP
+			}
+
+		case <-ctx.Done():
+			t.Fatalf("did not recieve events")
+		}
+	}
+
+}
+
 func TestSubType(t *testing.T) {
 	bus := NewBus()
 	sub, err := bus.Subscribe([]interface{}{new(EventA), new(EventB)})

go.mod

@@ -3,6 +3,11 @@ module github.com/libp2p/go-eventbus
 go 1.12
 
 require (
-	github.com/libp2p/go-libp2p-core v0.5.0
+	github.com/ipfs/go-cid v0.0.5 // indirect
+	github.com/libp2p/go-buffer-pool v0.0.2 // indirect
+	github.com/libp2p/go-libp2p-core v0.5.2-0.20200417060929-6957bf8a421d
 	github.com/libp2p/go-libp2p-testing v0.1.1
+	github.com/multiformats/go-multiaddr v0.2.1 // indirect
+	github.com/stretchr/testify v1.4.0
+	go.opencensus.io v0.22.3 // indirect
 )

go.sum

@@ -43,12 +43,16 @@ github.com/ipfs/go-cid v0.0.1/go.mod h1:GHWU/WuQdMPmIosc4Yn1bcCT7dSeX4lBafM7iqUP
 github.com/ipfs/go-cid v0.0.2/go.mod h1:GHWU/WuQdMPmIosc4Yn1bcCT7dSeX4lBafM7iqUPQvM=
 github.com/ipfs/go-cid v0.0.3 h1:UIAh32wymBpStoe83YCzwVQQ5Oy/H0FdxvUS6DJDzms=
 github.com/ipfs/go-cid v0.0.3/go.mod h1:GHWU/WuQdMPmIosc4Yn1bcCT7dSeX4lBafM7iqUPQvM=
+github.com/ipfs/go-cid v0.0.4 h1:UlfXKrZx1DjZoBhQHmNHLC1fK1dUJDN20Y28A7s+gJ8=
+github.com/ipfs/go-cid v0.0.4/go.mod h1:4LLaPOQwmk5z9LBgQnpkivrx8BJjUyGwTXCd5Xfj6+M=
 github.com/ipfs/go-cid v0.0.5 h1:o0Ix8e/ql7Zb5UVUJEUfjsWCIY8t48++9lR8qi6oiJU=
 github.com/ipfs/go-cid v0.0.5/go.mod h1:plgt+Y5MnOey4vO4UlUazGqdbEXuFYitED67FexhXog=
 github.com/jbenet/go-cienv v0.1.0/go.mod h1:TqNnHUmJgXau0nCzC7kXWeotg3J9W34CUv5Djy1+FlA=
 github.com/jbenet/goprocess v0.0.0-20160826012719-b497e2f366b8/go.mod h1:Ly/wlsjFq/qrU3Rar62tu1gASgGw6chQbSh/XgIIXCY=
 github.com/jbenet/goprocess v0.1.3 h1:YKyIEECS/XvcfHtBzxtjBBbWK+MbvA6dG8ASiqwvr10=
 github.com/jbenet/goprocess v0.1.3/go.mod h1:5yspPrukOVuOLORacaBi858NqyClJPQxYZlqdZVfqY4=
+github.com/jbenet/goprocess v0.1.4 h1:DRGOFReOMqqDNXwW70QkacFW0YN9QnwLV0Vqk+3oU0o=
+github.com/jbenet/goprocess v0.1.4/go.mod h1:5yspPrukOVuOLORacaBi858NqyClJPQxYZlqdZVfqY4=
 github.com/jessevdk/go-flags v0.0.0-20141203071132-1679536dcc89/go.mod h1:4FA24M0QyGHXBuZZK/XkWh8h0e1EYbRYJSGM75WSRxI=
 github.com/jessevdk/go-flags v1.4.0/go.mod h1:4FA24M0QyGHXBuZZK/XkWh8h0e1EYbRYJSGM75WSRxI=
 github.com/jrick/logrotate v1.0.0/go.mod h1:LNinyqDIJnpAur+b8yyulnQw/wDuN1+BYKlTRt3OuAQ=
@@ -75,8 +79,16 @@ github.com/libp2p/go-libp2p-core v0.2.5 h1:iP1PIiIrlRrGbE1fYq2918yBc5NlCH3pFuIPS
 github.com/libp2p/go-libp2p-core v0.2.5/go.mod h1:6+5zJmKhsf7yHn1RbmYDu08qDUpIUxGdqHuEZckmZOA=
 github.com/libp2p/go-libp2p-core v0.3.0 h1:F7PqduvrztDtFsAa/bcheQ3azmNo+Nq7m8hQY5GiUW8=
 github.com/libp2p/go-libp2p-core v0.3.0/go.mod h1:ACp3DmS3/N64c2jDzcV429ukDpicbL6+TrrxANBjPGw=
+github.com/libp2p/go-libp2p-core v0.3.2-0.20200415071619-8fb76f42df50 h1:A/euch2haQOL/a9Z4OA6Sv8hAsamD3IaTX/Wje/wbqI=
+github.com/libp2p/go-libp2p-core v0.3.2-0.20200415071619-8fb76f42df50/go.mod h1:thvWy0hvaSBhnVBaW37BvzgVV68OUhgJJLAa6almrII=
+github.com/libp2p/go-libp2p-core v0.3.2-0.20200415154218-9126769533e2 h1:3j584ZSRFrrS0ZPfDKqiPtjnLo8enn4WH8xhdRkYa+o=
+github.com/libp2p/go-libp2p-core v0.3.2-0.20200415154218-9126769533e2/go.mod h1:thvWy0hvaSBhnVBaW37BvzgVV68OUhgJJLAa6almrII=
+github.com/libp2p/go-libp2p-core v0.3.2-0.20200416170247-0a7a9856715c h1:IYaFZg3eDAGtXS32hN8qZ/QFbal9+ASqZuNOnyRkV3g=
+github.com/libp2p/go-libp2p-core v0.3.2-0.20200416170247-0a7a9856715c/go.mod h1:thvWy0hvaSBhnVBaW37BvzgVV68OUhgJJLAa6almrII=
 github.com/libp2p/go-libp2p-core v0.5.0 h1:FBQ1fpq2Fo/ClyjojVJ5AKXlKhvNc/B6U0O+7AN1ffE=
 github.com/libp2p/go-libp2p-core v0.5.0/go.mod h1:49XGI+kc38oGVwqSBhDEwytaAxgZasHhFfQKibzTls0=
+github.com/libp2p/go-libp2p-core v0.5.2-0.20200417060929-6957bf8a421d h1:ig8zIKt/shtRBOZqaEsJ/GX+LEpxqJ3CfIk0dKciZXI=
+github.com/libp2p/go-libp2p-core v0.5.2-0.20200417060929-6957bf8a421d/go.mod h1:uN7L2D4EvPCvzSH5SrhR72UWbnSGpt5/a35Sm4upn4Y=
 github.com/libp2p/go-libp2p-testing v0.0.4 h1:Qev57UR47GcLPXWjrunv5aLIQGO4n9mhI/8/EIrEEFc=
 github.com/libp2p/go-libp2p-testing v0.0.4/go.mod h1:gvchhf3FQOtBdr+eFUABet5a4MBLK8jM3V4Zghvmi+E=
 github.com/libp2p/go-libp2p-testing v0.1.1 h1:U03z3HnGI7Ni8Xx6ONVZvUFOAzWYmolWf5W5jAOPNmU=
@@ -138,6 +150,7 @@ github.com/multiformats/go-varint v0.0.5/go.mod h1:3Ls8CIEsrijN6+B7PbrXRPxHRPuXS
 github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/ginkgo v1.7.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/gomega v1.4.3/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1CpauHY=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/sirupsen/logrus v1.2.0/go.mod h1:LxeOpSwHxABJmUn/MG1IvRgCAasNZTLOkJPxbbu5VWo=
 github.com/smola/gocompat v0.2.0 h1:6b1oIMlUXIpz//VKEDzPVBK8KG7beVwmHIUEBIs/Pns=
@@ -152,6 +165,7 @@ github.com/src-d/envconfig v1.0.0/go.mod h1:Q9YQZ7BKITldTBnoxsE5gOeB5y66RyPXeue/
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/x-cray/logrus-prefixed-formatter v0.5.2/go.mod h1:2duySbKsL6M18s5GU7VPsoEPHyzalCE06qoARUCeBBE=
 go.opencensus.io v0.21.0/go.mod h1:mSImk1erAIZhrmZN+AvHh14ztQfjbGwt4TtuofqLduU=
@@ -164,6 +178,7 @@ golang.org/x/crypto v0.0.0-20190211182817-74369b46fc67/go.mod h1:6SG95UA2DQfeDnf
 golang.org/x/crypto v0.0.0-20190225124518-7f87c0fbb88b/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20190426145343-a29dc8fdc734/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/crypto v0.0.0-20190611184440-5c40567a22f8 h1:1wopBVtVdWnn03fZelqdXTqk7U7zPQCb+T4rbU9ZEoU=
 golang.org/x/crypto v0.0.0-20190611184440-5c40567a22f8/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20190618222545-ea8f1a30c443 h1:IcSOAf4PyMp3U3XbIEj1/xJ2BjNN2jWv7JoyOsMxXUU=
 golang.org/x/crypto v0.0.0-20190618222545-ea8f1a30c443/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
@@ -218,5 +233,6 @@ gopkg.in/src-d/go-cli.v0 v0.0.0-20181105080154-d492247bbc0d/go.mod h1:z+K8VcOYVY
 gopkg.in/src-d/go-log.v1 v1.0.1/go.mod h1:GN34hKP0g305ysm2/hctJ0Y8nWP3zxXXJ8GFabTyABE=
 gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7/go.mod h1:dt/ZhP58zS4L8KSrWDmTeBkI65Dw0HsyUHuEVlX15mw=
 gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=