Add a new function to make it possible to parse a list of snapshots
at once.  This is a counterpart to an earlier patch making it
possible to produce all snapshots in a single XML string, and
intentionally parses the same top-level element <snapshots> with
an optional attribute current='name'.

Note that since we know we started with no relations at all, and
since checking parent relationships per-snapshot is not viable as
we don't control which order the snapshots appear in, that we are
fine with doing a final pass to update all parent/child
relationships among the definitions.

Signed-off-by: Eric Blake <eblake@redhat.com>
---
 src/conf/snapshot_conf.h |   7 +++
 src/conf/snapshot_conf.c | 111 +++++++++++++++++++++++++++++++++++++++
 src/libvirt_private.syms |   1 +
 3 files changed, 119 insertions(+)

diff --git a/src/conf/snapshot_conf.h b/src/conf/snapshot_conf.h
index 69a7750b0b..f8af991907 100644
--- a/src/conf/snapshot_conf.h
+++ b/src/conf/snapshot_conf.h
@@ -132,6 +132,13 @@ virDomainSnapshotDefPtr virDomainSnapshotDefParseNode(xmlDocPtr xml,
                                                       virCapsPtr caps,
                                                       virDomainXMLOptionPtr xmlopt,
                                                       unsigned int flags);
+int virDomainSnapshotObjListParse(const char *xmlStr,
+                                  const unsigned char *domain_uuid,
+                                  virDomainSnapshotObjListPtr snapshots,
+                                  virDomainSnapshotObjPtr *current_snap,
+                                  virCapsPtr caps,
+                                  virDomainXMLOptionPtr xmlopt,
+                                  unsigned int flags);
 void virDomainSnapshotDefFree(virDomainSnapshotDefPtr def);
 char *virDomainSnapshotDefFormat(const char *uuidstr,
                                  virDomainSnapshotDefPtr def,
diff --git a/src/conf/snapshot_conf.c b/src/conf/snapshot_conf.c
index a5b05eadf4..52742d82d6 100644
--- a/src/conf/snapshot_conf.c
+++ b/src/conf/snapshot_conf.c
@@ -507,6 +507,117 @@ virDomainSnapshotRedefineValidate(virDomainSnapshotDefPtr def,
 }


+/* Parse a <snapshots> XML entry into snapshots, which must start empty.
+ * Any <domain> sub-elements of a <domainsnapshot> must match domain_uuid.
+ */
+int
+virDomainSnapshotObjListParse(const char *xmlStr,
+                              const unsigned char *domain_uuid,
+                              virDomainSnapshotObjListPtr snapshots,
+                              virDomainSnapshotObjPtr *current_snap,
+                              virCapsPtr caps,
+                              virDomainXMLOptionPtr xmlopt,
+                              unsigned int flags)
+{
+    int ret = -1;
+    xmlDocPtr xml;
+    xmlNodePtr root;
+    xmlXPathContextPtr ctxt = NULL;
+    int n;
+    size_t i;
+    int keepBlanksDefault = xmlKeepBlanksDefault(0);
+    VIR_AUTOFREE(xmlNodePtr *) nodes = NULL;
+    VIR_AUTOFREE(char *) current = NULL;
+
+    if (!(flags & VIR_DOMAIN_SNAPSHOT_PARSE_REDEFINE) ||
+        (flags & VIR_DOMAIN_SNAPSHOT_PARSE_INTERNAL)) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("incorrect flags for bulk parse"));
+        return -1;
+    }
+    if (snapshots->metaroot.nchildren || *current_snap) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                       _("bulk define of snapshots only possible with "
+                         "no existing snapshot"));
+        return -1;
+    }
+
+    if (!(xml = virXMLParse(NULL, xmlStr, _("(domain_snapshot)"))))
+        goto cleanup;
+
+    root = xmlDocGetRootElement(xml);
+    if (!virXMLNodeNameEqual(root, "snapshots")) {
+        virReportError(VIR_ERR_XML_ERROR,
+                       _("unexpected root element <%s>, "
+                         "expecting <snapshots>"), root->name);
+        goto cleanup;
+    }
+    ctxt = xmlXPathNewContext(xml);
+    if (ctxt == NULL) {
+        virReportOOMError();
+        goto cleanup;
+    }
+    ctxt->node = root;
+    current = virXMLPropString(root, "current");
+
+    if ((n = virXPathNodeSet("./domainsnapshot", ctxt, &nodes)) < 0)
+        goto cleanup;
+    if (!n) {
+        virReportError(VIR_ERR_XML_ERROR, "%s",
+                       _("expected at least one <domainsnapshot> child"));
+        goto cleanup;
+    }
+
+    for (i = 0; i < n; i++) {
+        virDomainSnapshotDefPtr def;
+        virDomainSnapshotObjPtr snap;
+
+        def = virDomainSnapshotDefParseNode(xml, nodes[i], caps, xmlopt, flags);
+        if (!def)
+            goto cleanup;
+        if (!(snap = virDomainSnapshotAssignDef(snapshots, def))) {
+            virDomainSnapshotDefFree(def);
+            goto cleanup;
+        }
+        if (virDomainSnapshotRedefineValidate(def, domain_uuid, NULL, NULL,
+                                              flags) < 0)
+            goto cleanup;
+    }
+
+    if (virDomainSnapshotUpdateRelations(snapshots) < 0) {
+        virReportError(VIR_ERR_XML_ERROR, "%s",
+                       _("<snapshots> contains inconsistent parent-child "
+                         "relationships"));
+        goto cleanup;
+    }
+
+    if (current) {
+        if (!(*current_snap = virDomainSnapshotFindByName(snapshots,
+                                                          current))) {
+            virReportError(VIR_ERR_NO_DOMAIN_SNAPSHOT,
+                           _("no snapshot matching current='%s'"), current);
+            goto cleanup;
+        }
+        (*current_snap)->def->current = true;
+    }
+
+    ret = 0;
+ cleanup:
+    if (ret < 0) {
+        /* There were no snapshots before this call; so on error, just
+         * blindly delete anything created before the failure. */
+        virHashRemoveAll(snapshots->objs);
+        snapshots->metaroot.nchildren = 0;
+        snapshots->metaroot.first_child = NULL;
+    }
+    VIR_FREE(current);
+    xmlXPathFreeContext(ctxt);
+    xmlFreeDoc(xml);
+    xmlKeepBlanksDefault(keepBlanksDefault);
+    return ret;
+}
+
+
 /**
  * virDomainSnapshotDefAssignExternalNames:
  * @def: snapshot def object
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 35e0c6d9dc..395e1f8764 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -899,6 +899,7 @@ virDomainSnapshotObjListFree;
 virDomainSnapshotObjListGetNames;
 virDomainSnapshotObjListNew;
 virDomainSnapshotObjListNum;
+virDomainSnapshotObjListParse;
 virDomainSnapshotObjListRemove;
 virDomainSnapshotRedefinePrep;
 virDomainSnapshotStateTypeFromString;
-- 
2.20.1

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On 3/4/19 10:34 PM, Eric Blake wrote:
> Add a new function to make it possible to parse a list of snapshots
> at once.  This is a counterpart to an earlier patch making it
> possible to produce all snapshots in a single XML string, and
> intentionally parses the same top-level element <snapshots> with
> an optional attribute current='name'.
> 
> Note that since we know we started with no relations at all, and
> since checking parent relationships per-snapshot is not viable as
> we don't control which order the snapshots appear in, that we are
> fine with doing a final pass to update all parent/child
> relationships among the definitions.
> 
> Signed-off-by: Eric Blake <eblake@redhat.com>
> ---
>  src/conf/snapshot_conf.h |   7 +++
>  src/conf/snapshot_conf.c | 111 +++++++++++++++++++++++++++++++++++++++
>  src/libvirt_private.syms |   1 +
>  3 files changed, 119 insertions(+)
> 
> diff --git a/src/conf/snapshot_conf.h b/src/conf/snapshot_conf.h
> index 69a7750b0b..f8af991907 100644
> --- a/src/conf/snapshot_conf.h
> +++ b/src/conf/snapshot_conf.h
> @@ -132,6 +132,13 @@ virDomainSnapshotDefPtr virDomainSnapshotDefParseNode(xmlDocPtr xml,
>                                                        virCapsPtr caps,
>                                                        virDomainXMLOptionPtr xmlopt,
>                                                        unsigned int flags);
> +int virDomainSnapshotObjListParse(const char *xmlStr,
> +                                  const unsigned char *domain_uuid,
> +                                  virDomainSnapshotObjListPtr snapshots,
> +                                  virDomainSnapshotObjPtr *current_snap,
> +                                  virCapsPtr caps,
> +                                  virDomainXMLOptionPtr xmlopt,
> +                                  unsigned int flags);
>  void virDomainSnapshotDefFree(virDomainSnapshotDefPtr def);
>  char *virDomainSnapshotDefFormat(const char *uuidstr,
>                                   virDomainSnapshotDefPtr def,
> diff --git a/src/conf/snapshot_conf.c b/src/conf/snapshot_conf.c
> index a5b05eadf4..52742d82d6 100644
> --- a/src/conf/snapshot_conf.c
> +++ b/src/conf/snapshot_conf.c
> @@ -507,6 +507,117 @@ virDomainSnapshotRedefineValidate(virDomainSnapshotDefPtr def,
>  }
> 
> 
> +/* Parse a <snapshots> XML entry into snapshots, which must start empty.
> + * Any <domain> sub-elements of a <domainsnapshot> must match domain_uuid.
> + */
> +int
> +virDomainSnapshotObjListParse(const char *xmlStr,
> +                              const unsigned char *domain_uuid,
> +                              virDomainSnapshotObjListPtr snapshots,
> +                              virDomainSnapshotObjPtr *current_snap,
> +                              virCapsPtr caps,
> +                              virDomainXMLOptionPtr xmlopt,
> +                              unsigned int flags)
> +{
> +    int ret = -1;
> +    xmlDocPtr xml;
> +    xmlNodePtr root;
> +    xmlXPathContextPtr ctxt = NULL;
> +    int n;
> +    size_t i;
> +    int keepBlanksDefault = xmlKeepBlanksDefault(0);
> +    VIR_AUTOFREE(xmlNodePtr *) nodes = NULL;
> +    VIR_AUTOFREE(char *) current = NULL;
> +
> +    if (!(flags & VIR_DOMAIN_SNAPSHOT_PARSE_REDEFINE) ||
> +        (flags & VIR_DOMAIN_SNAPSHOT_PARSE_INTERNAL)) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       _("incorrect flags for bulk parse"));
> +        return -1;
> +    }
> +    if (snapshots->metaroot.nchildren || *current_snap) {
> +        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> +                       _("bulk define of snapshots only possible with "
> +                         "no existing snapshot"));
> +        return -1;
> +    }
> +
> +    if (!(xml = virXMLParse(NULL, xmlStr, _("(domain_snapshot)"))))
> +        goto cleanup;

Could just be return -1

> +
> +    root = xmlDocGetRootElement(xml);
> +    if (!virXMLNodeNameEqual(root, "snapshots")) {
> +        virReportError(VIR_ERR_XML_ERROR,
> +                       _("unexpected root element <%s>, "
> +                         "expecting <snapshots>"), root->name);
> +        goto cleanup;
> +    }
> +    ctxt = xmlXPathNewContext(xml);
> +    if (ctxt == NULL) {
> +        virReportOOMError();
> +        goto cleanup;
> +    }
> +    ctxt->node = root;
> +    current = virXMLPropString(root, "current");
> +
> +    if ((n = virXPathNodeSet("./domainsnapshot", ctxt, &nodes)) < 0)
> +        goto cleanup;
> +    if (!n) {
> +        virReportError(VIR_ERR_XML_ERROR, "%s",
> +                       _("expected at least one <domainsnapshot> child"));
> +        goto cleanup;
> +    }
> +
> +    for (i = 0; i < n; i++) {
> +        virDomainSnapshotDefPtr def;
> +        virDomainSnapshotObjPtr snap;
> +
> +        def = virDomainSnapshotDefParseNode(xml, nodes[i], caps, xmlopt, flags);
> +        if (!def)
> +            goto cleanup;
> +        if (!(snap = virDomainSnapshotAssignDef(snapshots, def))) {
> +            virDomainSnapshotDefFree(def);
> +            goto cleanup;
> +        }
> +        if (virDomainSnapshotRedefineValidate(def, domain_uuid, NULL, NULL,
> +                                              flags) < 0)
> +            goto cleanup;
> +    }
> +
> +    if (virDomainSnapshotUpdateRelations(snapshots) < 0) {
> +        virReportError(VIR_ERR_XML_ERROR, "%s",
> +                       _("<snapshots> contains inconsistent parent-child "
> +                         "relationships"));
> +        goto cleanup;
> +    }
> +
> +    if (current) {
> +        if (!(*current_snap = virDomainSnapshotFindByName(snapshots,
> +                                                          current))) {
> +            virReportError(VIR_ERR_NO_DOMAIN_SNAPSHOT,
> +                           _("no snapshot matching current='%s'"), current);
> +            goto cleanup;
> +        }
> +        (*current_snap)->def->current = true;
> +    }
> +
> +    ret = 0;
> + cleanup:
> +    if (ret < 0) {
> +        /* There were no snapshots before this call; so on error, just
> +         * blindly delete anything created before the failure. */
> +        virHashRemoveAll(snapshots->objs);
> +        snapshots->metaroot.nchildren = 0;
> +        snapshots->metaroot.first_child = NULL;
> +    }
> +    VIR_FREE(current);

Unnecessary / VIR_AUTOFREE

Reviewed-by: John Ferlan <jferlan@redhat.com>

John

> +    xmlXPathFreeContext(ctxt);
> +    xmlFreeDoc(xml);
> +    xmlKeepBlanksDefault(keepBlanksDefault);
> +    return ret;
> +}
> +
> +
>  /**
>   * virDomainSnapshotDefAssignExternalNames:
>   * @def: snapshot def object
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index 35e0c6d9dc..395e1f8764 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -899,6 +899,7 @@ virDomainSnapshotObjListFree;
>  virDomainSnapshotObjListGetNames;
>  virDomainSnapshotObjListNew;
>  virDomainSnapshotObjListNum;
> +virDomainSnapshotObjListParse;
>  virDomainSnapshotObjListRemove;
>  virDomainSnapshotRedefinePrep;
>  virDomainSnapshotStateTypeFromString;
> 

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