qemu: Add QMPSocket specific type

Instead of open coding the QMP socket type, we now have a specific type
for it.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

qemu.go

@@ -391,10 +391,18 @@ func (rtc RTC) Valid() bool {
 	return true
 }
 
+// QMPSocketType is the type of socket used for QMP communication.
+type QMPSocketType string
+
+const (
+	// Unix socket for QMP.
+	Unix QMPSocketType = "unix"
+)
+
 // QMPSocket represents a qemu QMP socket configuration.
 type QMPSocket struct {
 	// Type is the socket type (e.g. "unix").
-	Type string
+	Type QMPSocketType
 
 	// Name is the socket name.
 	Name string
@@ -406,6 +414,15 @@ type QMPSocket struct {
 	NoWait bool
 }
 
+// Valid returns true if the QMPSocket structure is valid and complete.
+func (qmp QMPSocket) Valid() bool {
+	if qmp.Type == "" || qmp.Name == "" {
+		return false
+	}
+
+	return true
+}
+
 // SMP is the multi processors configuration structure.
 type SMP struct {
 	// CPUs is the number of VCPUs made available to qemu.
@@ -545,22 +562,24 @@ func appendCPUModel(params []string, config Config) []string {
 }
 
 func appendQMPSocket(params []string, config Config) []string {
-	if config.QMPSocket.Type != "" && config.QMPSocket.Name != "" {
-		var qmpParams []string
-
-		qmpParams = append(qmpParams, fmt.Sprintf("%s:", config.QMPSocket.Type))
-		qmpParams = append(qmpParams, fmt.Sprintf("%s", config.QMPSocket.Name))
-		if config.QMPSocket.Server == true {
-			qmpParams = append(qmpParams, ",server")
-			if config.QMPSocket.NoWait == true {
-				qmpParams = append(qmpParams, ",nowait")
-			}
-		}
-
-		params = append(params, "-qmp")
-		params = append(params, strings.Join(qmpParams, ""))
+	if config.QMPSocket.Valid() == false {
+		return nil
 	}
 
+	var qmpParams []string
+
+	qmpParams = append(qmpParams, fmt.Sprintf("%s:", config.QMPSocket.Type))
+	qmpParams = append(qmpParams, fmt.Sprintf("%s", config.QMPSocket.Name))
+	if config.QMPSocket.Server == true {
+		qmpParams = append(qmpParams, ",server")
+		if config.QMPSocket.NoWait == true {
+			qmpParams = append(qmpParams, ",nowait")
+		}
+	}
+
+	params = append(params, "-qmp")
+	params = append(params, strings.Join(qmpParams, ""))
+
 	return params
 }
 

qemu_test.go

@@ -259,7 +259,7 @@ func TestAppendQMPSocketServer(t *testing.T) {
 
 func TestAppendQMPSocket(t *testing.T) {
 	qmp := QMPSocket{
-		Type:   "unix",
+		Type:   Unix,
 		Name:   "cc-qmp",
 		Server: false,
 	}