use generics for asyncTasks, no type assertion required (#14)

* tweaks

* add test for generic version

* continueFunc in generic

* somewhat working

* update to go 1.18

.github/workflows/go.yml

@@ -13,23 +13,15 @@ jobs:
     runs-on: ubuntu-latest
     steps:
 
-    - name: Set up Go 1.13
+    - name: Set up Go 1.18
       uses: actions/setup-go@v1
       with:
-        go-version: 1.13
+        go-version: 1.18
       id: go
 
     - name: Check out code into the Go module directory
       uses: actions/checkout@v2
 
-    - name: Get dependencies
-      run: |
-        go get -v -t -d ./...
-        if [ -f Gopkg.toml ]; then
-            curl https://raw.githubusercontent.com/golang/dep/master/install.sh | sh
-            dep ensure
-        fi
-
     - name: Build
       run: go build -v .
 

continue_with.go

@@ -3,13 +3,11 @@ package asynctask
 import "context"
 
 // ContinueFunc is a function that can be connected to previous task with ContinueWith
-type ContinueFunc func(context.Context, interface{}) (interface{}, error)
+type ContinueFunc[T any, S any] func(context.Context, *T) (*S, error)
 
-// ContinueWith start the function when current task is done.
-// result from previous task will be passed in, if no error.
-func (tsk *TaskStatus) ContinueWith(ctx context.Context, next ContinueFunc) *TaskStatus {
-	return Start(ctx, func(fCtx context.Context) (interface{}, error) {
-		result, err := tsk.Wait(fCtx)
+func ContinueWith[T any, S any](ctx context.Context, tsk *Task[T], next ContinueFunc[T, S]) *Task[S] {
+	return Start(ctx, func(fCtx context.Context) (*S, error) {
+		result, err := tsk.Result(fCtx)
 		if err != nil {
 			return nil, err
 		}

continue_with_test.go

@@ -9,8 +9,8 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func getAdvancedCountingTask(countFrom, step int, sleepInterval time.Duration) asynctask.AsyncFunc {
-	return func(ctx context.Context) (interface{}, error) {
+func getAdvancedCountingTask(countFrom int, step int, sleepInterval time.Duration) asynctask.AsyncFunc[int] {
+	return func(ctx context.Context) (*int, error) {
 		t := ctx.Value(testContextKey).(*testing.T)
 
 		result := countFrom
@@ -21,56 +21,56 @@ func getAdvancedCountingTask(countFrom, step int, sleepInterval time.Duration) a
 				result++
 			case <-ctx.Done():
 				t.Log("work canceled")
-				return result, nil
+				return &result, nil
 			}
 		}
-		return result, nil
+		return &result, nil
 	}
 }
 
 func TestContinueWith(t *testing.T) {
 	t.Parallel()
 	ctx := newTestContext(t)
 	t1 := asynctask.Start(ctx, getAdvancedCountingTask(0, 10, 20*time.Millisecond))
-	t2 := t1.ContinueWith(ctx, func(fCtx context.Context, input interface{}) (interface{}, error) {
-		fromPrevTsk := input.(int)
+	t2 := asynctask.ContinueWith(ctx, t1, func(fCtx context.Context, input *int) (*int, error) {
+		fromPrevTsk := *input
 		return getAdvancedCountingTask(fromPrevTsk, 10, 20*time.Millisecond)(fCtx)
 	})
-	t3 := t1.ContinueWith(ctx, func(fCtx context.Context, input interface{}) (interface{}, error) {
-		fromPrevTsk := input.(int)
+	t3 := asynctask.ContinueWith(ctx, t1, func(fCtx context.Context, input *int) (*int, error) {
+		fromPrevTsk := *input
 		return getAdvancedCountingTask(fromPrevTsk, 12, 20*time.Millisecond)(fCtx)
 	})
 
-	result, err := t2.Wait(ctx)
+	result, err := t2.Result(ctx)
 	assert.NoError(t, err)
 	assert.Equal(t, asynctask.StateCompleted, t2.State(), "Task should complete with no error")
-	assert.Equal(t, result, 20)
+	assert.Equal(t, *result, 20)
 
-	result, err = t3.Wait(ctx)
+	result, err = t3.Result(ctx)
 	assert.NoError(t, err)
 	assert.Equal(t, asynctask.StateCompleted, t3.State(), "Task should complete with no error")
-	assert.Equal(t, result, 22)
+	assert.Equal(t, *result, 22)
 }
 
 func TestContinueWithFailureCase(t *testing.T) {
 	t.Parallel()
 	ctx := newTestContext(t)
 	t1 := asynctask.Start(ctx, getErrorTask("devide by 0", 10*time.Millisecond))
-	t2 := t1.ContinueWith(ctx, func(fCtx context.Context, input interface{}) (interface{}, error) {
-		fromPrevTsk := input.(int)
+	t2 := asynctask.ContinueWith(ctx, t1, func(fCtx context.Context, input *int) (*int, error) {
+		fromPrevTsk := *input
 		return getAdvancedCountingTask(fromPrevTsk, 10, 20*time.Millisecond)(fCtx)
 	})
-	t3 := t1.ContinueWith(ctx, func(fCtx context.Context, input interface{}) (interface{}, error) {
-		fromPrevTsk := input.(int)
+	t3 := asynctask.ContinueWith(ctx, t1, func(fCtx context.Context, input *int) (*int, error) {
+		fromPrevTsk := *input
 		return getAdvancedCountingTask(fromPrevTsk, 12, 20*time.Millisecond)(fCtx)
 	})
 
-	_, err := t2.Wait(ctx)
+	_, err := t2.Result(ctx)
 	assert.Error(t, err)
 	assert.Equal(t, asynctask.StateFailed, t2.State(), "Task2 should fail since preceeding task failed")
 	assert.Equal(t, "devide by 0", err.Error())
 
-	_, err = t3.Wait(ctx)
+	_, err = t3.Result(ctx)
 	assert.Error(t, err)
 	assert.Equal(t, asynctask.StateFailed, t3.State(), "Task3 should fail since preceeding task failed")
 	assert.Equal(t, "devide by 0", err.Error())

error_test.go

@@ -10,27 +10,15 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-type structError struct{}
-
-func (pe structError) Error() string {
-	return "Error from struct type"
-}
-
-type pointerError struct{}
-
-func (pe *pointerError) Error() string {
-	return "Error from pointer type"
-}
-
-func getPanicTask(sleepDuration time.Duration) asynctask.AsyncFunc {
-	return func(ctx context.Context) (interface{}, error) {
+func getPanicTask(sleepDuration time.Duration) asynctask.AsyncFunc[string] {
+	return func(ctx context.Context) (*string, error) {
 		time.Sleep(sleepDuration)
 		panic("yo")
 	}
 }
 
-func getErrorTask(errorString string, sleepDuration time.Duration) asynctask.AsyncFunc {
-	return func(ctx context.Context) (interface{}, error) {
+func getErrorTask(errorString string, sleepDuration time.Duration) asynctask.AsyncFunc[int] {
+	return func(ctx context.Context) (*int, error) {
 		time.Sleep(sleepDuration)
 		return nil, errors.New(errorString)
 	}
@@ -49,12 +37,12 @@ func TestTimeoutCase(t *testing.T) {
 	// I can continue wait with longer time
 	rawResult, err := tsk.WaitWithTimeout(ctx, 2*time.Second)
 	assert.NoError(t, err)
-	assert.Equal(t, 9, rawResult)
+	assert.Equal(t, 9, *rawResult)
 
 	// any following Wait should complete immediately
 	rawResult, err = tsk.WaitWithTimeout(ctx, 2*time.Nanosecond)
 	assert.NoError(t, err)
-	assert.Equal(t, 9, rawResult)
+	assert.Equal(t, 9, *rawResult)
 }
 
 func TestPanicCase(t *testing.T) {
@@ -79,49 +67,3 @@ func TestErrorCase(t *testing.T) {
 	assert.False(t, errors.Is(err, context.DeadlineExceeded), "not expecting DeadlineExceeded")
 	assert.Equal(t, "dummy error", err.Error())
 }
-
-func TestPointerErrorCase(t *testing.T) {
-	t.Parallel()
-	ctx, cancelFunc := newTestContextWithTimeout(t, 3*time.Second)
-	defer cancelFunc()
-
-	// nil point of a type that implement error
-	var pe *pointerError = nil
-	// pass this nil pointer to error interface
-	var err error = pe
-	// now you get a non-nil error
-	assert.False(t, err == nil, "reason this test is needed")
-
-	tsk := asynctask.Start(ctx, func(ctx context.Context) (interface{}, error) {
-		time.Sleep(100 * time.Millisecond)
-		var pe *pointerError = nil
-		return "Done", pe
-	})
-
-	result, err := tsk.Wait(ctx)
-	assert.NoError(t, err)
-	assert.Equal(t, result, "Done")
-}
-
-func TestStructErrorCase(t *testing.T) {
-	t.Parallel()
-	ctx, cancelFunc := newTestContextWithTimeout(t, 3*time.Second)
-	defer cancelFunc()
-
-	// nil point of a type that implement error
-	var se structError
-	// pass this nil pointer to error interface
-	var err error = se
-	// now you get a non-nil error
-	assert.False(t, err == nil, "reason this test is needed")
-
-	tsk := asynctask.Start(ctx, func(ctx context.Context) (interface{}, error) {
-		time.Sleep(100 * time.Millisecond)
-		var se structError
-		return "Done", se
-	})
-
-	result, err := tsk.Wait(ctx)
-	assert.NoError(t, err)
-	assert.Equal(t, result, "Done")
-}

go.mod

@@ -1,5 +1,11 @@
 module github.com/Azure/go-asynctask
 
-go 1.13
+go 1.18
 
-require github.com/stretchr/testify v1.7.0
+require github.com/stretchr/testify v1.7.1
+
+require (
+	github.com/davecgh/go-spew v1.1.0 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c // indirect
+)

go.sum

@@ -2,10 +2,9 @@ github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 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/stretchr/objx v0.1.0 h1:4G4v2dO3VZwixGIRoQ5Lfboy6nUhCyYzaqnIAPPhYs4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
-github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.7.1 h1:5TQK59W5E3v0r2duFAb7P95B6hEeOyEnHRa8MjYSMTY=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=