resources: Simplify the resource Compare functions

This removes one level of indentation and simplifies the code.

docs/resource-guide.md

@@ -344,25 +344,26 @@ some way.
 #### Example
 ```golang
 // Compare two resources and return if they are equivalent.
-func (obj *FooRes) Compare(res Res) bool {
+func (obj *FooRes) Compare(r Res) bool {
-	switch res.(type) {
+	// we can only compare FooRes to others of the same resource kind
-	case *FooRes: // only compare to other resources of the Foo kind!
+	res, ok := r.(*FooRes)
-		res := res.(*FileRes)
+	if !ok {
+		return false
+	}
 	if !obj.BaseRes.Compare(res) { // call base Compare
 		return false
 	}
 	if obj.Name != res.Name {
 		return false
 	}
+
 	if obj.whatever != res.whatever {
 		return false
 	}
 	if obj.Flag != res.Flag {
 		return false
 	}
-	default:
+
-		return false // different kind of resource
-	}
 	return true // they must match!
 }
 ```

resources/augeas.go

@@ -268,20 +268,19 @@ func (obj *AugeasRes) GroupCmp(r Res) bool {
 }
 
 // Compare two resources and return if they are equivalent.
-func (obj *AugeasRes) Compare(res Res) bool {
+func (obj *AugeasRes) Compare(r Res) bool {
-	switch res.(type) {
+	// we can only compare AugeasRes to others of the same resource kind
-	// we can only compare AugeasRes to others of the same resource
+	res, ok := r.(*AugeasRes)
-	case *AugeasRes:
+	if !ok {
-		res := res.(*AugeasRes)
+		return false
+	}
 	if !obj.BaseRes.Compare(res) { // call base Compare
 		return false
 	}
 	if obj.Name != res.Name {
 		return false
 	}
-	default:
+
-		return false
-	}
 	return true
 }
 

resources/exec.go

@@ -340,17 +340,19 @@ func (obj *ExecRes) GroupCmp(r Res) bool {
 }
 
 // Compare two resources and return if they are equivalent.
-func (obj *ExecRes) Compare(res Res) bool {
+func (obj *ExecRes) Compare(r Res) bool {
-	switch res.(type) {
+	// we can only compare ExecRes to others of the same resource kind
-	case *ExecRes:
+	res, ok := r.(*ExecRes)
-		res := res.(*ExecRes)
+	if !ok {
+		return false
+	}
 	if !obj.BaseRes.Compare(res) { // call base Compare
 		return false
 	}
-
 	if obj.Name != res.Name {
 		return false
 	}
+
 	if obj.Cmd != res.Cmd {
 		return false
 	}
@@ -372,9 +374,7 @@ func (obj *ExecRes) Compare(res Res) bool {
 	if obj.IfShell != res.IfShell {
 		return false
 	}
-	default:
+
-		return false
-	}
 	return true
 }
 

resources/file.go

@@ -942,17 +942,19 @@ func (obj *FileRes) GroupCmp(r Res) bool {
 }
 
 // Compare two resources and return if they are equivalent.
-func (obj *FileRes) Compare(res Res) bool {
+func (obj *FileRes) Compare(r Res) bool {
-	switch res.(type) {
+	// we can only compare FileRes to others of the same resource kind
-	case *FileRes:
+	res, ok := r.(*FileRes)
-		res := res.(*FileRes)
+	if !ok {
+		return false
+	}
 	if !obj.BaseRes.Compare(res) { // call base Compare
 		return false
 	}
-
 	if obj.Name != res.Name {
 		return false
 	}
+
 	if obj.path != res.path {
 		return false
 	}
@@ -976,9 +978,7 @@ func (obj *FileRes) Compare(res Res) bool {
 	if obj.Force != res.Force {
 		return false
 	}
-	default:
+
-		return false
-	}
 	return true
 }
 

resources/hostname.go

@@ -252,16 +252,19 @@ func (obj *HostnameRes) GroupCmp(r Res) bool {
 }
 
 // Compare two resources and return if they are equivalent.
-func (obj *HostnameRes) Compare(res Res) bool {
+func (obj *HostnameRes) Compare(r Res) bool {
-	switch res := res.(type) {
+	// we can only compare HostnameRes to others of the same resource kind
-	// we can only compare HostnameRes to others of the same resource
+	res, ok := r.(*HostnameRes)
-	case *HostnameRes:
+	if !ok {
+		return false
+	}
 	if !obj.BaseRes.Compare(res) { // call base Compare
 		return false
 	}
 	if obj.Name != res.Name {
 		return false
 	}
+
 	if obj.PrettyHostname != res.PrettyHostname {
 		return false
 	}
@@ -271,9 +274,7 @@ func (obj *HostnameRes) Compare(res Res) bool {
 	if obj.TransientHostname != res.TransientHostname {
 		return false
 	}
-	default:
+
-		return false
-	}
 	return true
 }
 

resources/kv.go

@@ -252,11 +252,12 @@ func (obj *KVRes) GroupCmp(r Res) bool {
 }
 
 // Compare two resources and return if they are equivalent.
-func (obj *KVRes) Compare(res Res) bool {
+func (obj *KVRes) Compare(r Res) bool {
-	switch res.(type) {
+	// we can only compare KVRes to others of the same resource kind
-	// we can only compare KVRes to others of the same resource
+	res, ok := r.(*KVRes)
-	case *KVRes:
+	if !ok {
-		res := res.(*KVRes)
+		return false
+	}
 	if !obj.BaseRes.Compare(res) { // call base Compare
 		return false
 	}
@@ -278,9 +279,7 @@ func (obj *KVRes) Compare(res Res) bool {
 	if obj.SkipCmpStyle != res.SkipCmpStyle {
 		return false
 	}
-	default:
+
-		return false
-	}
 	return true
 }
 

resources/msg.go

@@ -210,13 +210,16 @@ func (obj *MsgRes) AutoEdges() AutoEdge {
 }
 
 // Compare two resources and return if they are equivalent.
-func (obj *MsgRes) Compare(res Res) bool {
+func (obj *MsgRes) Compare(r Res) bool {
-	switch res.(type) {
+	// we can only compare MsgRes to others of the same resource kind
-	case *MsgRes:
+	res, ok := r.(*MsgRes)
-		res := res.(*MsgRes)
+	if !ok {
+		return false
+	}
 	if !obj.BaseRes.Compare(res) {
 		return false
 	}
+
 	if obj.Body != res.Body {
 		return false
 	}
@@ -231,9 +234,7 @@ func (obj *MsgRes) Compare(res Res) bool {
 			return false
 		}
 	}
-	default:
+
-		return false
-	}
 	return true
 }
 

resources/noop.go

@@ -123,21 +123,20 @@ func (obj *NoopRes) GroupCmp(r Res) bool {
 }
 
 // Compare two resources and return if they are equivalent.
-func (obj *NoopRes) Compare(res Res) bool {
+func (obj *NoopRes) Compare(r Res) bool {
-	switch res.(type) {
+	// we can only compare NoopRes to others of the same resource kind
-	// we can only compare NoopRes to others of the same resource
+	res, ok := r.(*NoopRes)
-	case *NoopRes:
+	if !ok {
-		res := res.(*NoopRes)
+		return false
-		// calling base Compare is unneeded for the noop res
+	}
-		//if !obj.BaseRes.Compare(res) { // call base Compare
+	// calling base Compare is probably unneeded for the noop res, but do it
-		//	return false
+	if !obj.BaseRes.Compare(res) { // call base Compare
-		//}
+		return false
+	}
 	if obj.Name != res.Name {
 		return false
 	}
-	default:
+
-		return false
-	}
 	return true
 }
 

resources/nspawn.go

@@ -275,22 +275,23 @@ func (obj *NspawnRes) GroupCmp(r Res) bool {
 }
 
 // Compare two resources and return if they are equivalent.
-func (obj *NspawnRes) Compare(res Res) bool {
+func (obj *NspawnRes) Compare(r Res) bool {
-	switch res.(type) {
+	// we can only compare NspawnRes to others of the same resource kind
-	case *NspawnRes:
+	res, ok := r.(*NspawnRes)
-		res := res.(*NspawnRes)
+	if !ok {
+		return false
+	}
 	if !obj.BaseRes.Compare(res) {
 		return false
 	}
 	if obj.Name != res.Name {
 		return false
 	}
+
 	if !obj.svc.Compare(res.svc) {
 		return false
 	}
-	default:
+
-		return false
-	}
 	return true
 }
 

resources/password.go

@@ -322,18 +322,19 @@ func (obj *PasswordRes) GroupCmp(r Res) bool {
 }
 
 // Compare two resources and return if they are equivalent.
-func (obj *PasswordRes) Compare(res Res) bool {
+func (obj *PasswordRes) Compare(r Res) bool {
-	switch res.(type) {
+	// we can only compare PasswordRes to others of the same resource kind
-	// we can only compare PasswordRes to others of the same resource
+	res, ok := r.(*PasswordRes)
-	case *PasswordRes:
+	if !ok {
-		res := res.(*PasswordRes)
+		return false
+	}
 	if !obj.BaseRes.Compare(res) { // call base Compare
 		return false
 	}
-
 	if obj.Name != res.Name {
 		return false
 	}
+
 	if obj.Length != res.Length {
 		return false
 	}
@@ -345,9 +346,7 @@ func (obj *PasswordRes) Compare(res Res) bool {
 	if obj.CheckRecovery != res.CheckRecovery {
 		return false
 	}
-	default:
+
-		return false
-	}
 	return true
 }
 

resources/pkg.go

@@ -482,17 +482,19 @@ func (obj *PkgRes) GroupCmp(r Res) bool {
 }
 
 // Compare two resources and return if they are equivalent.
-func (obj *PkgRes) Compare(res Res) bool {
+func (obj *PkgRes) Compare(r Res) bool {
-	switch res.(type) {
+	// we can only compare PkgRes to others of the same resource kind
-	case *PkgRes:
+	res, ok := r.(*PkgRes)
-		res := res.(*PkgRes)
+	if !ok {
+		return false
+	}
 	if !obj.BaseRes.Compare(res) { // call base Compare
 		return false
 	}
-
 	if obj.Name != res.Name {
 		return false
 	}
+
 	if obj.State != res.State {
 		return false
 	}
@@ -505,9 +507,7 @@ func (obj *PkgRes) Compare(res Res) bool {
 	if obj.AllowUnsupported != res.AllowUnsupported {
 		return false
 	}
-	default:
+
-		return false
-	}
 	return true
 }
 

resources/resources_test.go

@@ -22,9 +22,49 @@ import (
 	"encoding/base64"
 	"encoding/gob"
 	"testing"
-	//"github.com/purpleidea/mgmt/event"
 )
 
+func TestCompare1(t *testing.T) {
+	r1 := &NoopRes{}
+	r2 := &NoopRes{}
+	r3 := &FileRes{}
+
+	if !r1.Compare(r2) || !r2.Compare(r1) {
+		t.Error("The two resources do not match!")
+	}
+
+	if r1.Compare(r3) || r3.Compare(r1) {
+		t.Error("The two resources should not match!")
+	}
+}
+
+func TestCompare2(t *testing.T) {
+	r1 := &NoopRes{
+		BaseRes: BaseRes{
+			Name: "noop1",
+			MetaParams: MetaParams{
+				Noop: true,
+			},
+		},
+	}
+	r2 := &NoopRes{
+		BaseRes: BaseRes{
+			Name: "noop1", // same nampe
+			MetaParams: MetaParams{
+				Noop: false, // different noop
+			},
+		},
+	}
+
+	if !r2.Compare(r1) { // going from noop(false) -> noop(true) is okay!
+		t.Error("The two resources do not match!")
+	}
+
+	if r1.Compare(r2) { // going from noop(true) -> noop(false) is not okay!
+		t.Error("The two resources should not match!")
+	}
+}
+
 func TestMiscEncodeDecode1(t *testing.T) {
 	var err error
 	//gob.Register( &NoopRes{} ) // happens in noop.go : init()

resources/svc.go

@@ -427,17 +427,19 @@ func (obj *SvcRes) GroupCmp(r Res) bool {
 }
 
 // Compare two resources and return if they are equivalent.
-func (obj *SvcRes) Compare(res Res) bool {
+func (obj *SvcRes) Compare(r Res) bool {
-	switch res.(type) {
+	// we can only compare SvcRes to others of the same resource kind
-	case *SvcRes:
+	res, ok := r.(*SvcRes)
-		res := res.(*SvcRes)
+	if !ok {
+		return false
+	}
 	if !obj.BaseRes.Compare(res) { // call base Compare
 		return false
 	}
-
 	if obj.Name != res.Name {
 		return false
 	}
+
 	if obj.State != res.State {
 		return false
 	}
@@ -447,9 +449,7 @@ func (obj *SvcRes) Compare(res Res) bool {
 	if obj.Session != res.Session {
 		return false
 	}
-	default:
+
-		return false
-	}
 	return true
 }
 

resources/timer.go

@@ -135,22 +135,23 @@ func (obj *TimerRes) AutoEdges() AutoEdge {
 }
 
 // Compare two resources and return if they are equivalent.
-func (obj *TimerRes) Compare(res Res) bool {
+func (obj *TimerRes) Compare(r Res) bool {
-	switch res.(type) {
+	// we can only compare TimerRes to others of the same resource kind
-	case *TimerRes:
+	res, ok := r.(*TimerRes)
-		res := res.(*TimerRes)
+	if !ok {
+		return false
+	}
 	if !obj.BaseRes.Compare(res) {
 		return false
 	}
 	if obj.Name != res.Name {
 		return false
 	}
+
 	if obj.Interval != res.Interval {
 		return false
 	}
-	default:
+
-		return false
-	}
 	return true
 }
 

resources/virt.go

@@ -1076,17 +1076,19 @@ func (obj *VirtRes) AutoEdges() AutoEdge {
 }
 
 // Compare two resources and return if they are equivalent.
-func (obj *VirtRes) Compare(res Res) bool {
+func (obj *VirtRes) Compare(r Res) bool {
-	switch res.(type) {
+	// we can only compare VirtRes to others of the same resource kind
-	case *VirtRes:
+	res, ok := r.(*VirtRes)
-		res := res.(*VirtRes)
+	if !ok {
+		return false
+	}
 	if !obj.BaseRes.Compare(res) { // call base Compare
 		return false
 	}
-
 	if obj.Name != res.Name {
 		return false
 	}
+
 	if obj.URI != res.URI {
 		return false
 	}
@@ -1129,9 +1131,7 @@ func (obj *VirtRes) Compare(res Res) bool {
 	//if obj.Filesystem != res.Filesystem {
 	//	return false
 	//}
-	default:
+
-		return false
-	}
 	return true
 }