conf: Use virXMLFormatElement to format disk 'driver' element

Formatting of 'driver' already used a separate buffer but was part of
the main function. Separate it and remove bunch of unnecessary temporary
variables.

Note that some checks are removed but they are not really necessary
anyways.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

src/conf/domain_conf.c

@@ -23692,6 +23692,70 @@ virDomainDiskDefFormatIotune(virBufferPtr buf,
 #undef FORMAT_IOTUNE
 
 
+static int
+virDomainDiskDefFormatDriver(virBufferPtr buf,
+                             virDomainDiskDefPtr disk)
+{
+    virBuffer driverBuf = VIR_BUFFER_INITIALIZER;
+    int ret = -1;
+
+    virBufferEscapeString(&driverBuf, " name='%s'", virDomainDiskGetDriver(disk));
+
+    if (disk->src->format > 0)
+        virBufferAsprintf(&driverBuf, " type='%s'",
+                          virStorageFileFormatTypeToString(disk->src->format));
+
+    if (disk->cachemode)
+        virBufferAsprintf(&driverBuf, " cache='%s'",
+                          virDomainDiskCacheTypeToString(disk->cachemode));
+
+    if (disk->error_policy)
+        virBufferAsprintf(&driverBuf, " error_policy='%s'",
+                          virDomainDiskErrorPolicyTypeToString(disk->error_policy));
+
+    if (disk->rerror_policy)
+        virBufferAsprintf(&driverBuf, " rerror_policy='%s'",
+                          virDomainDiskErrorPolicyTypeToString(disk->rerror_policy));
+
+    if (disk->iomode)
+        virBufferAsprintf(&driverBuf, " io='%s'",
+                          virDomainDiskIoTypeToString(disk->iomode));
+
+    if (disk->ioeventfd)
+        virBufferAsprintf(&driverBuf, " ioeventfd='%s'",
+                          virTristateSwitchTypeToString(disk->ioeventfd));
+
+    if (disk->event_idx)
+        virBufferAsprintf(&driverBuf, " event_idx='%s'",
+                          virTristateSwitchTypeToString(disk->event_idx));
+
+    if (disk->copy_on_read)
+        virBufferAsprintf(&driverBuf, " copy_on_read='%s'",
+                          virTristateSwitchTypeToString(disk->copy_on_read));
+
+    if (disk->discard)
+        virBufferAsprintf(&driverBuf, " discard='%s'",
+                          virDomainDiskDiscardTypeToString(disk->discard));
+
+    if (disk->iothread)
+        virBufferAsprintf(&driverBuf, " iothread='%u'", disk->iothread);
+
+    if (disk->detect_zeroes)
+        virBufferAsprintf(&driverBuf, " detect_zeroes='%s'",
+                          virDomainDiskDetectZeroesTypeToString(disk->detect_zeroes));
+
+    if (disk->queues)
+        virBufferAsprintf(&driverBuf, " queues='%u'", disk->queues);
+
+    virDomainVirtioOptionsFormat(&driverBuf, disk->virtio);
+
+    ret = virXMLFormatElement(buf, "driver", &driverBuf, NULL);
+
+    virBufferFreeAndReset(&driverBuf);
+    return ret;
+}
+
+
 static int
 virDomainDiskDefFormat(virBufferPtr buf,
                        virDomainDiskDefPtr def,
@@ -23701,17 +23765,7 @@ virDomainDiskDefFormat(virBufferPtr buf,
     const char *type = virStorageTypeToString(def->src->type);
     const char *device = virDomainDiskDeviceTypeToString(def->device);
     const char *bus = virDomainDiskBusTypeToString(def->bus);
-    const char *cachemode = virDomainDiskCacheTypeToString(def->cachemode);
-    const char *error_policy = virDomainDiskErrorPolicyTypeToString(def->error_policy);
-    const char *rerror_policy = virDomainDiskErrorPolicyTypeToString(def->rerror_policy);
-    const char *iomode = virDomainDiskIoTypeToString(def->iomode);
-    const char *ioeventfd = virTristateSwitchTypeToString(def->ioeventfd);
-    const char *event_idx = virTristateSwitchTypeToString(def->event_idx);
-    const char *copy_on_read = virTristateSwitchTypeToString(def->copy_on_read);
     const char *sgio = virDomainDeviceSGIOTypeToString(def->sgio);
-    const char *discard = virDomainDiskDiscardTypeToString(def->discard);
-    const char *detect_zeroes = virDomainDiskDetectZeroesTypeToString(def->detect_zeroes);
-    virBuffer driverBuf = VIR_BUFFER_INITIALIZER;
 
     if (!type || !def->src->type) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
@@ -23728,16 +23782,6 @@ virDomainDiskDefFormat(virBufferPtr buf,
                        _("unexpected disk bus %d"), def->bus);
         return -1;
     }
-    if (!cachemode) {
-        virReportError(VIR_ERR_INTERNAL_ERROR,
-                       _("unexpected disk cache mode %d"), def->cachemode);
-        return -1;
-    }
-    if (!iomode) {
-        virReportError(VIR_ERR_INTERNAL_ERROR,
-                       _("unexpected disk io mode %d"), def->iomode);
-        return -1;
-    }
     if (!sgio) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
                        _("Unexpected disk sgio mode '%d'"), def->sgio);
@@ -23763,44 +23807,9 @@ virDomainDiskDefFormat(virBufferPtr buf,
     virBufferAddLit(buf, ">\n");
     virBufferAdjustIndent(buf, 2);
 
-    virBufferEscapeString(&driverBuf, " name='%s'", virDomainDiskGetDriver(def));
-    if (def->src->format > 0)
-        virBufferAsprintf(&driverBuf, " type='%s'",
-                          virStorageFileFormatTypeToString(def->src->format));
-    if (def->cachemode)
-        virBufferAsprintf(&driverBuf, " cache='%s'", cachemode);
-    if (def->error_policy)
-        virBufferAsprintf(&driverBuf, " error_policy='%s'", error_policy);
-    if (def->rerror_policy)
-        virBufferAsprintf(&driverBuf, " rerror_policy='%s'", rerror_policy);
-    if (def->iomode)
-        virBufferAsprintf(&driverBuf, " io='%s'", iomode);
-    if (def->ioeventfd)
-        virBufferAsprintf(&driverBuf, " ioeventfd='%s'", ioeventfd);
-    if (def->event_idx)
-        virBufferAsprintf(&driverBuf, " event_idx='%s'", event_idx);
-    if (def->copy_on_read)
-        virBufferAsprintf(&driverBuf, " copy_on_read='%s'", copy_on_read);
-    if (def->discard)
-        virBufferAsprintf(&driverBuf, " discard='%s'", discard);
-    if (def->iothread)
-        virBufferAsprintf(&driverBuf, " iothread='%u'", def->iothread);
-    if (def->detect_zeroes)
-        virBufferAsprintf(&driverBuf, " detect_zeroes='%s'", detect_zeroes);
-    if (def->queues)
-        virBufferAsprintf(&driverBuf, " queues='%u'", def->queues);
-
-    virDomainVirtioOptionsFormat(&driverBuf, def->virtio);
-
-    if (virBufferCheckError(&driverBuf) < 0)
+    if (virDomainDiskDefFormatDriver(buf, def) < 0)
         return -1;
 
-    if (virBufferUse(&driverBuf)) {
-        virBufferAddLit(buf, "<driver");
-        virBufferAddBuffer(buf, &driverBuf);
-        virBufferAddLit(buf, "/>\n");
-    }
-
     /* Format as child of <disk> if defined there; otherwise,
      * if defined as child of <source>, then format later */
     if (def->src->auth && !def->src->authInherited)