domaincaps: Store domain capability features in an array

Declare the capabilities as enum values and store them in an array. This
makes adding new features more straightforward and simplifies the
formatter which now doesn't require changing.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

src/conf/domain_capabilities.c

@@ -33,6 +33,15 @@ VIR_ENUM_IMPL(virDomainCapsCPUUsable,
               "unknown", "yes", "no",
 );
 
+
+VIR_ENUM_DECL(virDomainCapsFeature);
+VIR_ENUM_IMPL(virDomainCapsFeature,
+              VIR_DOMAIN_CAPS_FEATURE_LAST,
+              "iothreads",
+              "vmcoreinfo",
+              "genid",
+);
+
 static virClassPtr virDomainCapsClass;
 static virClassPtr virDomainCapsCPUModelsClass;
 
@@ -317,9 +326,10 @@ virDomainCapsEnumClear(virDomainCapsEnumPtr capsEnum)
 void
 virDomainCapsFeaturesInitUnsupported(virDomainCapsPtr caps)
 {
-    caps->iothreads = VIR_TRISTATE_BOOL_NO;
-    caps->vmcoreinfo = VIR_TRISTATE_BOOL_NO;
-    caps->genid = VIR_TRISTATE_BOOL_NO;
+    size_t i;
+
+    for (i = 0; i < VIR_DOMAIN_CAPS_FEATURE_LAST; i++)
+        caps->features[i] = VIR_TRISTATE_BOOL_NO;
 }
 
 
@@ -612,10 +622,19 @@ virDomainCapsFormatFeatures(const virDomainCaps *caps,
                             virBufferPtr buf)
 {
     g_auto(virBuffer) childBuf = VIR_BUFFER_INIT_CHILD(buf);
+    size_t i;
 
     virDomainCapsFeatureGICFormat(&childBuf, &caps->gic);
-    qemuDomainCapsFeatureFormatSimple(&childBuf, "vmcoreinfo", caps->vmcoreinfo);
-    qemuDomainCapsFeatureFormatSimple(&childBuf, "genid", caps->genid);
+
+    for (i = 0; i < VIR_DOMAIN_CAPS_FEATURE_LAST; i++) {
+        if (i == VIR_DOMAIN_CAPS_FEATURE_IOTHREADS)
+            continue;
+
+        qemuDomainCapsFeatureFormatSimple(&childBuf,
+                                          virDomainCapsFeatureTypeToString(i),
+                                          caps->features[i]);
+    }
+
     virDomainCapsFeatureSEVFormat(&childBuf, caps->sev);
 
     virXMLFormatElement(buf, "features", NULL, &childBuf);
@@ -641,7 +660,8 @@ virDomainCapsFormat(const virDomainCaps *caps)
     if (caps->maxvcpus)
         virBufferAsprintf(&buf, "<vcpu max='%d'/>\n", caps->maxvcpus);
 
-    qemuDomainCapsFeatureFormatSimple(&buf, "iothreads", caps->iothreads);
+    qemuDomainCapsFeatureFormatSimple(&buf, "iothreads",
+                                      caps->features[VIR_DOMAIN_CAPS_FEATURE_IOTHREADS]);
 
     virDomainCapsOSFormat(&buf, &caps->os);
     virDomainCapsCPUFormat(&buf, &caps->cpu);

src/conf/domain_capabilities.h

@@ -156,6 +156,14 @@ struct _virSEVCapability {
     unsigned int reduced_phys_bits;
 };
 
+typedef enum {
+    VIR_DOMAIN_CAPS_FEATURE_IOTHREADS = 0,
+    VIR_DOMAIN_CAPS_FEATURE_VMCOREINFO,
+    VIR_DOMAIN_CAPS_FEATURE_GENID,
+
+    VIR_DOMAIN_CAPS_FEATURE_LAST
+} virDomainCapsFeature;
+
 struct _virDomainCaps {
     virObjectLockable parent;
 
@@ -166,7 +174,6 @@ struct _virDomainCaps {
 
     /* Some machine specific info */
     int maxvcpus;
-    virTristateBool iothreads;  /* Whether I/O threads are supported or not. */
 
     virDomainCapsOS os;
     virDomainCapsCPU cpu;
@@ -178,10 +185,10 @@ struct _virDomainCaps {
     /* add new domain devices here */
 
     virDomainCapsFeatureGIC gic;
-    virTristateBool vmcoreinfo;
-    virTristateBool genid;
     virSEVCapabilityPtr sev;
     /* add new domain features here */
+
+    virTristateBool features[VIR_DOMAIN_CAPS_FEATURE_LAST];
 };
 
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(virDomainCaps, virObjectUnref);

src/qemu/qemu_capabilities.c

@@ -5285,7 +5285,7 @@ static void
 virQEMUCapsFillDomainIOThreadCaps(virQEMUCapsPtr qemuCaps,
                                   virDomainCapsPtr domCaps)
 {
-    domCaps->iothreads = virTristateBoolFromBool(
+    domCaps->features[VIR_DOMAIN_CAPS_FEATURE_IOTHREADS] = virTristateBoolFromBool(
             virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_IOTHREAD));
 }
 
@@ -5584,10 +5584,10 @@ virQEMUCapsFillDomainCaps(virCapsPtr caps,
         domCaps->maxvcpus = MIN(domCaps->maxvcpus, hostmaxvcpus);
     }
 
-    domCaps->vmcoreinfo = virTristateBoolFromBool(
+    domCaps->features[VIR_DOMAIN_CAPS_FEATURE_VMCOREINFO] = virTristateBoolFromBool(
             virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_VMCOREINFO));
 
-    domCaps->genid = virTristateBoolFromBool(
+    domCaps->features[VIR_DOMAIN_CAPS_FEATURE_GENID] = virTristateBoolFromBool(
             virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_VMGENID));
 
     if (virQEMUCapsFillDomainOSCaps(os,