pkg/predicate.go: add And and Or predicates

Author: joelanford

pkg/predicate/predicate.go

@@ -41,6 +41,8 @@ type Predicate interface {
 var _ Predicate = Funcs{}
 var _ Predicate = ResourceVersionChangedPredicate{}
 var _ Predicate = GenerationChangedPredicate{}
+var _ Predicate = or{}
+var _ Predicate = and{}
 
 // Funcs is a function that implements Predicate.
 type Funcs struct {
@@ -155,3 +157,93 @@ func (GenerationChangedPredicate) Update(e event.UpdateEvent) bool {
 	}
 	return e.MetaNew.GetGeneration() != e.MetaOld.GetGeneration()
 }
+
+// And returns a composite predicate that implements a logical AND of the predicates passed to it.
+func And(predicates ...Predicate) Predicate {
+	return and{predicates}
+}
+
+type and struct {
+	predicates []Predicate
+}
+
+func (a and) Create(e event.CreateEvent) bool {
+	for _, p := range a.predicates {
+		if !p.Create(e) {
+			return false
+		}
+	}
+	return true
+}
+
+func (a and) Update(e event.UpdateEvent) bool {
+	for _, p := range a.predicates {
+		if !p.Update(e) {
+			return false
+		}
+	}
+	return true
+}
+
+func (a and) Delete(e event.DeleteEvent) bool {
+	for _, p := range a.predicates {
+		if !p.Delete(e) {
+			return false
+		}
+	}
+	return true
+}
+
+func (a and) Generic(e event.GenericEvent) bool {
+	for _, p := range a.predicates {
+		if !p.Generic(e) {
+			return false
+		}
+	}
+	return true
+}
+
+// Or returns a composite predicate that implements a logical OR of the predicates passed to it.
+func Or(predicates ...Predicate) Predicate {
+	return or{predicates}
+}
+
+type or struct {
+	predicates []Predicate
+}
+
+func (o or) Create(e event.CreateEvent) bool {
+	for _, p := range o.predicates {
+		if p.Create(e) {
+			return true
+		}
+	}
+	return false
+}
+
+func (o or) Update(e event.UpdateEvent) bool {
+	for _, p := range o.predicates {
+		if p.Update(e) {
+			return true
+		}
+	}
+	return false
+}
+
+func (o or) Delete(e event.DeleteEvent) bool {
+	for _, p := range o.predicates {
+		if p.Delete(e) {
+			return true
+		}
+	}
+	return false
+}
+
+func (o or) Generic(e event.GenericEvent) bool {
+	for _, p := range o.predicates {
+		if p.Generic(e) {
+			return true
+		}
+	}
+	return false
+}

pkg/predicate/predicate_test.go

@@ -438,4 +438,57 @@ var _ = Describe("Predicate", func() {
 		})
 
 	})
+
+	Context("With a boolean predicate", func() {
+		funcs := func(pass bool) predicate.Funcs {
+			return predicate.Funcs{
+				CreateFunc: func(event.CreateEvent) bool {
+					return pass
+				},
+				DeleteFunc: func(event.DeleteEvent) bool {
+					return pass
+				},
+				UpdateFunc: func(event.UpdateEvent) bool {
+					return pass
+				},
+				GenericFunc: func(event.GenericEvent) bool {
+					return pass
+				},
+			}
+		}
+		passFuncs := funcs(true)
+		failFuncs := funcs(false)
+		Describe("When checking an And predicate", func() {
+			It("should return false when one of its predicates returns false", func() {
+				a := predicate.And(passFuncs, failFuncs)
+				Expect(a.Create(event.CreateEvent{})).To(BeFalse())
+				Expect(a.Update(event.UpdateEvent{})).To(BeFalse())
+				Expect(a.Delete(event.DeleteEvent{})).To(BeFalse())
+				Expect(a.Generic(event.GenericEvent{})).To(BeFalse())
+			})
+			It("should return true when all of its predicates return true", func() {
+				a := predicate.And(passFuncs, passFuncs)
+				Expect(a.Create(event.CreateEvent{})).To(BeTrue())
+				Expect(a.Update(event.UpdateEvent{})).To(BeTrue())
+				Expect(a.Delete(event.DeleteEvent{})).To(BeTrue())
+				Expect(a.Generic(event.GenericEvent{})).To(BeTrue())
+			})
+		})
+		Describe("When checking an Or predicate", func() {
+			It("should return true when one of its predicates returns true", func() {
+				o := predicate.Or(passFuncs, failFuncs)
+				Expect(o.Create(event.CreateEvent{})).To(BeTrue())
+				Expect(o.Update(event.UpdateEvent{})).To(BeTrue())
+				Expect(o.Delete(event.DeleteEvent{})).To(BeTrue())
+				Expect(o.Generic(event.GenericEvent{})).To(BeTrue())
+			})
+			It("should return false when all of its predicates return false", func() {
+				o := predicate.Or(failFuncs, failFuncs)
+				Expect(o.Create(event.CreateEvent{})).To(BeFalse())
+				Expect(o.Update(event.UpdateEvent{})).To(BeFalse())
+				Expect(o.Delete(event.DeleteEvent{})).To(BeFalse())
+				Expect(o.Generic(event.GenericEvent{})).To(BeFalse())
+			})
+		})
+	})
 })