add oneshot mono api. (#11)

* add oneshot mono api.

Author: jjeffcaii

Diff for: mono/mono_bench_test.go

@@ -0,0 +1,48 @@
+package mono_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/jjeffcaii/reactor-go/mono"
+)
+
+func BenchmarkJust(b *testing.B) {
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			mono.Just(1).Subscribe(context.Background())
+		}
+	})
+}
+
+func BenchmarkCreate(b *testing.B) {
+	gen := func(i context.Context, sink mono.Sink) {
+		sink.Success(1)
+	}
+	b.ResetTimer()
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			mono.Create(gen).Subscribe(context.Background())
+		}
+	})
+}
+
+func BenchmarkJustOneshot(b *testing.B) {
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			mono.JustOneshot(1).Subscribe(context.Background())
+		}
+	})
+}
+
+func BenchmarkCreateOneshot(b *testing.B) {
+	gen := func(i context.Context, sink mono.Sink) {
+		sink.Success(1)
+	}
+	b.ResetTimer()
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			mono.CreateOneshot(gen).Subscribe(context.Background())
+		}
+	})
+}

Diff for: mono/mono_error.go

@@ -8,14 +8,14 @@ import (
 )
 
 type monoError struct {
-	e error
+	inner error
 }
 
-func (p monoError) SubscribeWith(ctx context.Context, s reactor.Subscriber) {
+func (e monoError) SubscribeWith(ctx context.Context, s reactor.Subscriber) {
 	s.OnSubscribe(ctx, internal.EmptySubscription)
-	s.OnError(p.e)
+	s.OnError(e.inner)
 }
 
 func newMonoError(e error) monoError {
-	return monoError{e: e}
+	return monoError{inner: e}
 }

Diff for: mono/mono_test.go

@@ -290,49 +290,6 @@ func testContextDone(m mono.Mono, t *testing.T) {
 	assert.Error(t, err, "should catch error")
 }
 
-func BenchmarkNative(b *testing.B) {
-	var sum int64
-	b.ResetTimer()
-	b.RunParallel(func(pb *testing.PB) {
-		for pb.Next() {
-			var v Any = int64(1)
-			atomic.AddInt64(&sum, v.(int64))
-		}
-	})
-}
-
-func BenchmarkJust(b *testing.B) {
-	var sum int64
-	m := mono.Just(int64(1))
-	b.ResetTimer()
-	b.RunParallel(func(pb *testing.PB) {
-		s := reactor.NewSubscriber(reactor.OnNext(func(v Any) error {
-			atomic.AddInt64(&sum, v.(int64))
-			return nil
-		}))
-		for pb.Next() {
-			m.SubscribeWith(context.Background(), s)
-		}
-	})
-}
-
-func BenchmarkCreate(b *testing.B) {
-	var sum int64
-	m := mono.Create(func(i context.Context, sink mono.Sink) {
-		sink.Success(int64(1))
-	})
-	b.ResetTimer()
-	b.RunParallel(func(pb *testing.PB) {
-		s := reactor.NewSubscriber(reactor.OnNext(func(v Any) error {
-			atomic.AddInt64(&sum, v.(int64))
-			return nil
-		}))
-		for pb.Next() {
-			m.SubscribeWith(context.Background(), s)
-		}
-	})
-}
-
 func TestError(t *testing.T) {
 	mockErr := errors.New("this is a mock error")
 	var sig reactor.SignalType
@@ -438,3 +395,128 @@ func TestBlock(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Nil(t, v)
 }
+
+func TestOneshot(t *testing.T) {
+	for _, m := range []mono.Mono{
+		mono.JustOneshot(1),
+		mono.CreateOneshot(func(ctx context.Context, s mono.Sink) {
+			s.Success(1)
+		}),
+	} {
+		result, err := m.
+			Map(func(any reactor.Any) (reactor.Any, error) {
+				return any.(int) * 2, nil
+			}).
+			DoOnNext(func(v reactor.Any) error {
+				assert.Equal(t, 2, v.(int))
+				return nil
+			}).
+			DoOnError(func(e error) {
+				assert.FailNow(t, "unreachable")
+			}).
+			Block(context.Background())
+		assert.NoError(t, err)
+		assert.Equal(t, 2, result)
+	}
+
+	n, err := mono.JustOneshot(1).
+		FlatMap(func(any reactor.Any) mono.Mono {
+			return mono.Just(any.(int) * 3)
+		}).
+		Block(context.Background())
+	assert.NoError(t, err)
+	assert.Equal(t, 3, n)
+
+	discardCalls := new(int32)
+
+	mono.
+		CreateOneshot(func(ctx context.Context, s mono.Sink) {
+			s.Success(111)
+		}).
+		Filter(func(any reactor.Any) bool {
+			return any.(int) > 222
+		}).
+		DoOnDiscard(func(v reactor.Any) {
+			assert.Equal(t, 111, v)
+			atomic.AddInt32(discardCalls, 1)
+		}).
+		SwitchIfEmpty(mono.Just(333)).
+		DoOnNext(func(v reactor.Any) error {
+			assert.Equal(t, 333, v)
+			return nil
+		}).
+		Subscribe(context.Background())
+
+	assert.Equal(t, int32(1), atomic.LoadInt32(discardCalls))
+
+	_, err = mono.
+		CreateOneshot(func(ctx context.Context, s mono.Sink) {
+			time.Sleep(100 * time.Millisecond)
+			s.Success(1)
+		}).
+		Timeout(50 * time.Millisecond).
+		Block(context.Background())
+	assert.Error(t, err)
+	assert.True(t, reactor.IsCancelledError(err))
+
+	done := make(chan struct{})
+	now := time.Now()
+	mono.Just(1).
+		DoFinally(func(s reactor.SignalType) {
+			close(done)
+		}).
+		DelayElement(100*time.Millisecond).
+		Subscribe(context.Background(), reactor.OnNext(func(v reactor.Any) error {
+			assert.True(t, time.Since(now)/1e6 >= 100)
+			return nil
+		}))
+	<-done
+}
+
+func TestErrorOneshot(t *testing.T) {
+	fakeErr := errors.New("fake error")
+	finallyCalls := new(int32)
+	subscribeCalls := new(int32)
+	_, err := mono.
+		ErrorOneshot(fakeErr).
+		DoFinally(func(s reactor.SignalType) {
+			atomic.AddInt32(finallyCalls, 1)
+		}).
+		DoOnSubscribe(func(ctx context.Context, su reactor.Subscription) {
+			atomic.AddInt32(subscribeCalls, 1)
+		}).
+		DoOnCancel(func() {
+			assert.FailNow(t, "unreachable")
+		}).
+		DoOnNext(func(v reactor.Any) error {
+			assert.FailNow(t, "unreachable")
+			return nil
+		}).
+		DoOnError(func(e error) {
+			assert.Equal(t, fakeErr, e)
+		}).
+		SubscribeOn(scheduler.Parallel()).
+		Block(context.Background())
+	assert.Error(t, err, "should return error")
+	assert.Equal(t, fakeErr, err)
+	assert.Equal(t, int32(1), atomic.LoadInt32(finallyCalls))
+	assert.Equal(t, int32(1), atomic.LoadInt32(subscribeCalls))
+}
+
+func TestIsSubscribeOnParallel(t *testing.T) {
+	assert.False(t, mono.IsSubscribeAsync(mono.Just(1)))
+	assert.True(t, mono.IsSubscribeAsync(mono.Just(1).SubscribeOn(scheduler.Parallel())))
+	assert.True(t, mono.IsSubscribeAsync(mono.Just(1).SubscribeOn(scheduler.Single())))
+	assert.True(t, mono.IsSubscribeAsync(mono.JustOneshot(1).SubscribeOn(scheduler.Elastic())))
+}
+
+func TestJust(t *testing.T) {
+	assert.Panics(t, func() {
+		mono.Just(nil)
+	})
+	assert.Panics(t, func() {
+		mono.JustOneshot(nil)
+	})
+	assert.NotNil(t, mono.Just(1))
+	assert.NotNil(t, mono.JustOneshot(1))
+}

Diff for: mono/processor_test.go

@@ -2,6 +2,7 @@ package mono_test
 
 import (
 	"context"
+	"errors"
 	"testing"
 	"time"
 
@@ -51,3 +52,19 @@ func TestProcessor_Context(t *testing.T) {
 		Subscribe(ctx)
 	<-done
 }
+
+func TestProcessor_Error(t *testing.T) {
+	fakeErr := errors.New("fake error")
+	p := mono.CreateProcessor()
+	done := make(chan error, 1)
+	p.
+		DoOnError(func(e error) {
+			done <- e
+		}).
+		Subscribe(context.Background())
+
+	time.Sleep(100 * time.Millisecond)
+	p.Error(fakeErr)
+	e := <-done
+	assert.Equal(t, fakeErr, e)
+}

Diff for: mono/utils.go

@@ -2,17 +2,20 @@ package mono
 
 import (
 	"context"
-	"errors"
 	"time"
 )
 
 var empty = wrap(newMonoJust(nil))
-var errJustNilValue = errors.New("require non nil value")
+var _errJustNilValue = "require non nil value"
 
 func Error(e error) Mono {
 	return wrap(newMonoError(e))
 }
 
+func ErrorOneshot(e error) Mono {
+	return borrowOneshotWrapper(newMonoError(e))
+}
+
 func Empty() Mono {
 	return empty
 }
@@ -26,15 +29,26 @@ func JustOrEmpty(v Any) Mono {
 
 func Just(v Any) Mono {
 	if v == nil {
-		panic(errJustNilValue)
+		panic(_errJustNilValue)
 	}
 	return wrap(newMonoJust(v))
 }
 
+func JustOneshot(v Any) Mono {
+	if v == nil {
+		panic(_errJustNilValue)
+	}
+	return borrowOneshotWrapper(newMonoJust(v))
+}
+
 func Create(gen func(ctx context.Context, s Sink)) Mono {
 	return wrap(newMonoCreate(gen))
 }
 
+func CreateOneshot(gen func(ctx context.Context, s Sink)) Mono {
+	return borrowOneshotWrapper(newMonoCreate(gen))
+}
+
 func Delay(delay time.Duration) Mono {
 	return wrap(newMonoDelay(delay))
 }

Diff for: mono/wrapper.go

@@ -6,7 +6,6 @@ import (
 	"time"
 
 	"github.com/jjeffcaii/reactor-go"
-	"github.com/jjeffcaii/reactor-go/internal/subscribers"
 	"github.com/jjeffcaii/reactor-go/scheduler"
 )
 
@@ -69,7 +68,7 @@ func (p wrapper) DoOnSubscribe(fn reactor.FnOnSubscribe) Mono {
 }
 
 func (p wrapper) DelayElement(delay time.Duration) Mono {
-	return wrap(newMonoDelayElement(p.RawPublisher, delay, scheduler.Elastic()))
+	return wrap(newMonoDelayElement(p.RawPublisher, delay, scheduler.Parallel()))
 }
 
 func (p wrapper) Timeout(timeout time.Duration) Mono {
@@ -80,40 +79,15 @@ func (p wrapper) Timeout(timeout time.Duration) Mono {
 }
 
 func (p wrapper) Block(ctx context.Context) (Any, error) {
-	done := make(chan struct{})
-	vchan := make(chan reactor.Any, 1)
-	echan := make(chan error, 1)
-	b := subscribers.NewBlockSubscriber(done, vchan, echan)
-	p.SubscribeWith(ctx, b)
-	<-done
-
-	defer close(vchan)
-	defer close(echan)
-
-	select {
-	case value := <-vchan:
-		return value, nil
-	case err := <-echan:
-		return nil, err
-	default:
-		return nil, nil
-	}
+	return block(ctx, p.RawPublisher)
 }
 
 func (p wrapper) Success(v Any) {
-	p.mustProcessor().Success(v)
+	mustProcessor(p.RawPublisher).Success(v)
 }
 
 func (p wrapper) Error(e error) {
-	p.mustProcessor().Error(e)
-}
-
-func (p wrapper) mustProcessor() *processor {
-	pp, ok := p.RawPublisher.(*processor)
-	if !ok {
-		panic(errNotProcessor)
-	}
-	return pp
+	mustProcessor(p.RawPublisher).Error(e)
 }
 
 func wrap(r reactor.RawPublisher) wrapper {