Convert our usage of go-diodes into a simplified, generic version

utils/diodes/diodes.go

@@ -0,0 +1,38 @@
+package diodes
+
+import (
+	"context"
+
+	"code.cloudfoundry.org/go-diodes"
+)
+
+type Diode[T any] struct {
+	d *diodes.Waiter
+}
+
+type Alerter = diodes.Alerter
+
+type AlertFunc = diodes.AlertFunc
+
+func New[T any](ctx context.Context, size int, alerter Alerter) *Diode[T] {
+	return &Diode[T]{
+		d: diodes.NewWaiter(diodes.NewOneToOne(size, alerter), diodes.WithWaiterContext(ctx)),
+	}
+}
+
+func (d *Diode[T]) Put(data T) {
+	d.d.Set(diodes.GenericDataType(&data))
+}
+
+func (d *Diode[T]) TryNext() (*T, bool) {
+	data, ok := d.d.TryNext()
+	if !ok {
+		return nil, ok
+	}
+	return (*T)(data), true
+}
+
+func (d *Diode[T]) Next() *T {
+	data := d.d.Next()
+	return (*T)(data)
+}

utils/diodes/diodes_test.go

@@ -0,0 +1,62 @@
+package diodes_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/navidrome/navidrome/tests"
+	. "github.com/navidrome/navidrome/utils/diodes"
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+func TestDiodes(t *testing.T) {
+	tests.Init(t, false)
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Diodes Suite")
+}
+
+var _ = Describe("Diode", func() {
+	type message struct {
+		data string
+	}
+	var diode *Diode[message]
+	var ctx context.Context
+	var ctxCancel context.CancelFunc
+	var missed int
+
+	BeforeEach(func() {
+		missed = 0
+		ctx, ctxCancel = context.WithCancel(context.Background())
+		diode = New[message](ctx, 2, AlertFunc(func(m int) { missed = m }))
+	})
+
+	It("enqueues the data correctly", func() {
+		diode.Put(message{data: "1"})
+		diode.Put(message{data: "2"})
+		Expect(diode.Next()).To(Equal(&message{data: "1"}))
+		Expect(diode.Next()).To(Equal(&message{data: "2"}))
+		Expect(missed).To(BeZero())
+	})
+
+	It("drops messages when Diode is full", func() {
+		diode.Put(message{data: "1"})
+		diode.Put(message{data: "2"})
+		diode.Put(message{data: "3"})
+		next, ok := diode.TryNext()
+		Expect(ok).To(BeTrue())
+		Expect(next).To(Equal(&message{data: "3"}))
+
+		_, ok = diode.TryNext()
+		Expect(ok).To(BeFalse())
+
+		Expect(missed).To(Equal(2))
+	})
+
+	It("returns nil when Diode is empty and the context is canceled", func() {
+		diode.Put(message{data: "1"})
+		ctxCancel()
+		Expect(diode.Next()).To(Equal(&message{data: "1"}))
+		Expect(diode.Next()).To(BeNil())
+	})
+})