snapshot: indent domain xml when nesting

<domainsnapshot> is the first public instance of <domain> being
used as a sub-element, although we have two other private uses
(runtime state, and migration cookie).  Although indentation has
no effect on XML parsing, using it makes the output more consistent.

This uses virBuffer auto-indentation to obtain the effect, for all
but the portions of <domain> that are not generated a line at a
time into the same virBuffer.  Further patches will clean up the
remaining problems.

* src/conf/domain_conf.h (virDomainDefFormatInternal): New prototype.
* src/conf/domain_conf.c (virDomainDefFormatInternal): Export.
(virDomainObjFormat, virDomainSnapshotDefFormat): Update callers.
* src/libvirt_private.syms (domain_conf.h): Add new export.
* src/qemu/qemu_migration.c (qemuMigrationCookieXMLFormat): Use
new function.
(qemuMigrationCookieXMLFormatStr): Update caller.

src/conf/domain_conf.c

@@ -10559,14 +10559,13 @@ verify(((VIR_DOMAIN_XML_INTERNAL_STATUS |
 
 /* This internal version can accept VIR_DOMAIN_XML_INTERNAL_*,
  * whereas the public version cannot.  Also, it appends to an existing
- * buffer, rather than flattening to string.  Return -1 on failure.  */
+ * buffer (possibly with auto-indent), rather than flattening to string.
-static int
+ * Return -1 on failure.  */
+int
 virDomainDefFormatInternal(virDomainDefPtr def,
                            unsigned int flags,
                            virBufferPtr buf)
 {
-    /* XXX Also need to take an indentation parameter - either int or
-     * string prefix, so that snapshot xml gets uniform indentation.  */
     unsigned char *uuid;
     char uuidstr[VIR_UUID_STRING_BUFLEN];
     const char *type = NULL;
@@ -11056,8 +11055,10 @@ static char *virDomainObjFormat(virCapsPtr caps,
         ((caps->privateDataXMLFormat)(&buf, obj->privateData)) < 0)
         goto error;
 
+    virBufferAdjustIndent(&buf, 2);
     if (virDomainDefFormatInternal(obj->def, flags, &buf) < 0)
         goto error;
+    virBufferAdjustIndent(&buf, -2);
 
     virBufferAddLit(&buf, "</domstatus>\n");
 
@@ -12074,7 +12075,12 @@ char *virDomainSnapshotDefFormat(char *domain_uuid,
         virBufferAddLit(&buf, "  </disks>\n");
     }
     if (def->dom) {
-        virDomainDefFormatInternal(def->dom, flags, &buf);
+        virBufferAdjustIndent(&buf, 2);
+        if (virDomainDefFormatInternal(def->dom, flags, &buf) < 0) {
+            virBufferFreeAndReset(&buf);
+            return NULL;
+        }
+        virBufferAdjustIndent(&buf, -2);
     } else {
         virBufferAddLit(&buf, "  <domain>\n");
         virBufferAsprintf(&buf, "    <uuid>%s</uuid>\n", domain_uuid);

src/conf/domain_conf.h

@@ -1683,6 +1683,9 @@ int virDomainDefAddImplicitControllers(virDomainDefPtr def);
 
 char *virDomainDefFormat(virDomainDefPtr def,
                          unsigned int flags);
+int virDomainDefFormatInternal(virDomainDefPtr def,
+                               unsigned int flags,
+                               virBufferPtr buf);
 
 int virDomainCpuSetParse(const char **str,
                          char sep,

src/libvirt_private.syms

@@ -267,6 +267,7 @@ virDomainDefCheckABIStability;
 virDomainDefClearDeviceAliases;
 virDomainDefClearPCIAddresses;
 virDomainDefFormat;
+virDomainDefFormatInternal;
 virDomainDefFree;
 virDomainDefParseFile;
 virDomainDefParseNode;

src/qemu/qemu_migration.c

@@ -384,12 +384,12 @@ static void qemuMigrationCookieGraphicsXMLFormat(virBufferPtr buf,
 }
 
 
-static void qemuMigrationCookieXMLFormat(virBufferPtr buf,
+static int
-                                         qemuMigrationCookiePtr mig)
+qemuMigrationCookieXMLFormat(virBufferPtr buf,
+                             qemuMigrationCookiePtr mig)
 {
     char uuidstr[VIR_UUID_STRING_BUFLEN];
     char hostuuidstr[VIR_UUID_STRING_BUFLEN];
-    char *domXML;
     int i;
 
     virUUIDFormat(mig->uuid, uuidstr);
@@ -422,14 +422,17 @@ static void qemuMigrationCookieXMLFormat(virBufferPtr buf,
 
     if ((mig->flags & QEMU_MIGRATION_COOKIE_PERSISTENT) &&
         mig->persistent) {
-        domXML = virDomainDefFormat(mig->persistent,
+        virBufferAdjustIndent(buf, 2);
-                                    VIR_DOMAIN_XML_INACTIVE |
+        if (virDomainDefFormatInternal(mig->persistent,
-                                    VIR_DOMAIN_XML_SECURE);
+                                       VIR_DOMAIN_XML_INACTIVE |
-        virBufferAdd(buf, domXML, -1);
+                                       VIR_DOMAIN_XML_SECURE,
-        VIR_FREE(domXML);
+                                       buf) < 0)
+            return -1;
+        virBufferAdjustIndent(buf, -2);
     }
 
     virBufferAddLit(buf, "</qemu-migration>\n");
+    return 0;
 }
 
 
@@ -437,10 +440,14 @@ static char *qemuMigrationCookieXMLFormatStr(qemuMigrationCookiePtr mig)
 {
     virBuffer buf = VIR_BUFFER_INITIALIZER;
 
-    qemuMigrationCookieXMLFormat(&buf, mig);
+    if (qemuMigrationCookieXMLFormat(&buf, mig) < 0) {
+        virBufferFreeAndReset(&buf);
+        return NULL;
+    }
 
     if (virBufferError(&buf)) {
         virReportOOMError();
+        virBufferFreeAndReset(&buf);
         return NULL;
     }