blockstore: add tests for event system and benchmarks

Benchmark results:

BenchmarkEventFireSingle-12      	 1000000	        24.1 ns/op
BenchmarkEventFireMultiple-12    	 1000000	         4.37 ns/op

and zero allocations (to wide to fit).

License: MIT
Signed-off-by: Jakub Sztandera <kubuxu@protonmail.ch>

Author: Kubuxu

blocks/blockstore/blockstore.go

@@ -98,7 +98,7 @@ func NewBlockstore(d ds.Batching) Blockstore {
 	dsb = dd
 	return &blockstore{
 		datastore: dsb,
-		events:    &eventSystem{},
+		events:    newEventSystem(),
 	}
 }
 

blocks/blockstore/events.go

@@ -32,6 +32,10 @@ type eventSystem struct {
 	handlers map[EventID][]EventFunc
 }
 
+func newEventSystem() *eventSystem {
+	return &eventSystem{handlers: make(map[EventID][]EventFunc)}
+}
+
 func (es *eventSystem) addHandler(t EventID, ef EventFunc) {
 	es.lock.Lock()
 	defer es.lock.Unlock()

blocks/blockstore/events_test.go

@@ -0,0 +1,174 @@
+package blockstore
+
+import (
+	"testing"
+
+	"github.com/ipfs/go-ipfs/blocks/blocksutil"
+)
+
+func TestBasicEventHandling(t *testing.T) {
+	es := newEventSystem()
+	blkgen := blocksutil.NewBlockGenerator()
+	b := blkgen.Next()
+	e := &Event{
+		cid:   b.Cid(),
+		block: b,
+	}
+
+	ok := false
+	handler := func(ei *Event) (bool, error) {
+		if e != ei {
+			t.Fatal("event is different")
+		}
+		ok = true
+		return false, nil
+	}
+
+	es.addHandler(EventPostPut, handler)
+	es.fireEvent(EventPostPut, e)
+	if !ok {
+		t.Fatal("event was not fired")
+	}
+}
+
+func TestEventMarkedDone(t *testing.T) {
+	es := newEventSystem()
+	blkgen := blocksutil.NewBlockGenerator()
+	b := blkgen.Next()
+	e := &Event{
+		cid:   b.Cid(),
+		block: b,
+	}
+
+	count := 0
+	handler := func(ei *Event) (bool, error) {
+		if e != ei {
+			t.Fatal("event is different")
+		}
+		count++
+		return true, nil
+	}
+
+	es.addHandler(EventPostPut, handler)
+	es.addHandler(EventPostPut, handler)
+	es.addHandler(EventPostPut, handler)
+	es.fireEvent(EventPostPut, e)
+	if count != 1 {
+		t.Fatalf("expected to fire the handler 1 time, it was fired %d times", count)
+	}
+}
+
+func TestEventFireMultiple(t *testing.T) {
+	es := newEventSystem()
+	blkgen := blocksutil.NewBlockGenerator()
+	N := 10
+	evs := make([]*Event, N)
+	for i, _ := range evs {
+		b := blkgen.Next()
+		evs[i] = &Event{
+			cid:   b.Cid(),
+			block: b,
+		}
+	}
+
+	count := 0
+	handler := func(ei *Event) (bool, error) {
+		if evs[count] != ei {
+			t.Fatal("event is different")
+		}
+		count++
+		return false, nil
+	}
+
+	es.addHandler(EventPostPut, handler)
+	es.fireMany(EventPostPut, evs)
+	if count != N {
+		t.Fatalf("events were not fired, count should be %d, is %d", N, count)
+	}
+}
+
+func TestEventFireMultipleMarkDone(t *testing.T) {
+	es := newEventSystem()
+	blkgen := blocksutil.NewBlockGenerator()
+	N := 10
+	evs := make([]*Event, N)
+	for i, _ := range evs {
+		b := blkgen.Next()
+		evs[i] = &Event{
+			cid:   b.Cid(),
+			block: b,
+		}
+	}
+
+	count := 0
+	handler := func(ei *Event) (bool, error) {
+		if evs[count] != ei {
+			t.Fatal("event is different")
+		}
+		count++
+		return true, nil
+	}
+	failHandler := func(ei *Event) (bool, error) {
+		t.Fatal("this should not fire")
+		return false, nil
+	}
+
+	es.addHandler(EventPostPut, handler)
+	es.addHandler(EventPostPut, failHandler)
+	es.fireMany(EventPostPut, evs)
+	if count != N {
+		t.Fatalf("expected to fire the handler 1 time, it was fired %d times", count)
+	}
+}
+
+func BenchmarkEventFireSingle(b *testing.B) {
+	b.N = 1000000
+	es := newEventSystem()
+	blkgen := blocksutil.NewBlockGenerator()
+	evs := make([]*Event, b.N)
+	for i, _ := range evs {
+		b := blkgen.Next()
+		evs[i] = &Event{
+			cid:   b.Cid(),
+			block: b,
+		}
+	}
+	count := 0
+	h := func(ei *Event) (bool, error) {
+		count++
+		return false, nil
+	}
+	es.addHandler(EventPostPut, h)
+
+	b.ReportAllocs()
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		es.fireEvent(EventPostPut, evs[i])
+	}
+}
+
+func BenchmarkEventFireMultiple(b *testing.B) {
+	b.N = 1000000
+	es := newEventSystem()
+	blkgen := blocksutil.NewBlockGenerator()
+	evs := make([]*Event, b.N)
+	for i, _ := range evs {
+		b := blkgen.Next()
+		evs[i] = &Event{
+			cid:   b.Cid(),
+			block: b,
+		}
+	}
+	count := 0
+	h := func(ei *Event) (bool, error) {
+		count++
+		return false, nil
+	}
+	es.addHandler(EventPostPut, h)
+
+	b.ReportAllocs()
+	b.ResetTimer()
+
+	es.fireMany(EventPostPut, evs)
+}