conf: Add virCPUDefAddFeatureIfMissing

This new function adds a feature to a CPU definition only if it is not
present there yet.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Tim Wiederhake <twiederh@redhat.com>

src/conf/cpu_conf.c

@@ -861,6 +861,7 @@ virCPUDefFormatBuf(virBufferPtr buf,
 typedef enum {
     VIR_CPU_ADD_FEATURE_MODE_EXCLUSIVE, /* Fail if feature exists */
     VIR_CPU_ADD_FEATURE_MODE_UPDATE,    /* Add feature or update policy */
+    VIR_CPU_ADD_FEATURE_MODE_NEW,       /* Add feature if it does not exist */
 } virCPUDefAddFeatureMode;
 
 static int
@@ -876,6 +877,9 @@ virCPUDefAddFeatureInternal(virCPUDefPtr def,
 
     if ((feat = virCPUDefFindFeature(def, name))) {
         switch (mode) {
+        case VIR_CPU_ADD_FEATURE_MODE_NEW:
+            return 0;
+
         case VIR_CPU_ADD_FEATURE_MODE_UPDATE:
             feat->policy = policy;
             return 0;
@@ -920,6 +924,16 @@ virCPUDefAddFeature(virCPUDefPtr def,
 }
 
 
+int
+virCPUDefAddFeatureIfMissing(virCPUDefPtr def,
+                             const char *name,
+                             int policy)
+{
+    return virCPUDefAddFeatureInternal(def, name, policy,
+                                       VIR_CPU_ADD_FEATURE_MODE_NEW);
+}
+
+
 virCPUFeatureDefPtr
 virCPUDefFindFeature(virCPUDefPtr def,
                      const char *name)

src/conf/cpu_conf.h

@@ -229,6 +229,11 @@ virCPUDefUpdateFeature(virCPUDefPtr cpu,
                        const char *name,
                        int policy);
 
+int
+virCPUDefAddFeatureIfMissing(virCPUDefPtr def,
+                             const char *name,
+                             int policy);
+
 virCPUFeatureDefPtr
 virCPUDefFindFeature(virCPUDefPtr def,
                      const char *name);

src/libvirt_private.syms

@@ -96,6 +96,7 @@ virDomainCheckpointTypeToString;
 virCPUCacheModeTypeFromString;
 virCPUCacheModeTypeToString;
 virCPUDefAddFeature;
+virCPUDefAddFeatureIfMissing;
 virCPUDefCheckFeatures;
 virCPUDefCopy;
 virCPUDefCopyModel;