[libvirt] [PATCH 3/5] snapshot: refactor virsh snapshot parent computation
Daniel Veillard
veillard at redhat.com
Wed Sep 28 13:17:06 UTC 2011
On Sat, Sep 24, 2011 at 06:30:04PM -0600, Eric Blake wrote:
> Make parent computation reusable, using virDomainSnapshotGetParent
> when possible.
>
> * tools/virsh.c (vshGetSnapshotParent): New helper.
> (cmdSnapshotParent): Use it.
> ---
> tools/virsh.c | 66 ++++++++++++++++++++++++++++++++++++++++++++-------------
> 1 files changed, 51 insertions(+), 15 deletions(-)
>
> diff --git a/tools/virsh.c b/tools/virsh.c
> index 7b0533d..035b209 100644
> --- a/tools/virsh.c
> +++ b/tools/virsh.c
> @@ -246,6 +246,8 @@ typedef struct __vshControl {
> char *historyfile; /* readline history file name */
> bool useGetInfo; /* must use virDomainGetInfo, since
> virDomainGetState is not supported */
> + bool useSnapshotGetXML; /* must use virDomainSnapshotGetXMLDesc, since
> + virDomainSnapshotGetParent is missing */
> } __vshControl;
>
> typedef struct vshCmdGrp {
> @@ -613,6 +615,7 @@ vshReconnect(vshControl *ctl)
> vshError(ctl, "%s", _("Reconnected to the hypervisor"));
> disconnected = 0;
> ctl->useGetInfo = false;
> + ctl->useSnapshotGetXML = false;
> }
>
> /* ---------------
> @@ -760,6 +763,7 @@ cmdConnect(vshControl *ctl, const vshCmd *cmd)
> ctl->name = vshStrdup(ctl, name);
>
> ctl->useGetInfo = false;
> + ctl->useSnapshotGetXML = false;
> ctl->readonly = ro;
>
> ctl->conn = virConnectOpenAuth(ctl->name, virConnectAuthPtrDefault,
> @@ -12967,6 +12971,52 @@ cleanup:
> return ret;
> }
>
> +/* Helper function to get the name of a snapshot's parent. Caller
> + * must free the result. */
> +static char *
> +vshGetSnapshotParent(vshControl *ctl, virDomainSnapshotPtr snapshot)
> +{
> + virDomainSnapshotPtr parent = NULL;
> + char *xml = NULL;
> + xmlDocPtr xmldoc = NULL;
> + xmlXPathContextPtr ctxt = NULL;
> + char *parent_name = NULL;
> +
> + /* Try new API, since it is faster. */
> + if (!ctl->useSnapshotGetXML) {
> + parent = virDomainSnapshotGetParent(snapshot, 0);
> + if (parent) {
> + /* API works, and virDomainSnapshotGetName will succeed */
> + parent_name = vshStrdup(ctl, virDomainSnapshotGetName(snapshot));
> + goto cleanup;
> + }
> + if (last_error->code == VIR_ERR_NO_DOMAIN_SNAPSHOT) {
> + /* API works, and we found a root with no parent */
> + goto cleanup;
> + }
> + /* API didn't work, fall back to XML scraping. */
> + ctl->useSnapshotGetXML = true;
> + }
> +
> + xml = virDomainSnapshotGetXMLDesc(snapshot, 0);
> + if (!xml)
> + goto cleanup;
> +
> + xmldoc = virXMLParseStringCtxt(xml, _("(domain_snapshot)"), &ctxt);
> + if (!xmldoc)
> + goto cleanup;
> +
> + parent_name = virXPathString("string(/domainsnapshot/parent/name)", ctxt);
> +
> +cleanup:
> + if (parent)
> + virDomainSnapshotFree(parent);
> + xmlXPathFreeContext(ctxt);
> + xmlFreeDoc(xmldoc);
> + VIR_FREE(xml);
> + return parent_name;
> +}
> +
> /*
> * "snapshot-list" command
> */
> @@ -13220,10 +13270,7 @@ cmdSnapshotParent(vshControl *ctl, const vshCmd *cmd)
> bool ret = false;
> const char *name = NULL;
> virDomainSnapshotPtr snapshot = NULL;
> - char *xml = NULL;
> char *parent = NULL;
> - xmlDocPtr xmldoc = NULL;
> - xmlXPathContextPtr ctxt = NULL;
>
> if (!vshConnectionUsability(ctl, ctl->conn))
> goto cleanup;
> @@ -13239,15 +13286,7 @@ cmdSnapshotParent(vshControl *ctl, const vshCmd *cmd)
> if (snapshot == NULL)
> goto cleanup;
>
> - xml = virDomainSnapshotGetXMLDesc(snapshot, 0);
> - if (!xml)
> - goto cleanup;
> -
> - xmldoc = virXMLParseStringCtxt(xml, _("(domain_snapshot)"), &ctxt);
> - if (!xmldoc)
> - goto cleanup;
> -
> - parent = virXPathString("string(/domainsnapshot/parent/name)", ctxt);
> + parent = vshGetSnapshotParent(ctl, snapshot);
> if (!parent)
> goto cleanup;
>
> @@ -13257,9 +13296,6 @@ cmdSnapshotParent(vshControl *ctl, const vshCmd *cmd)
>
> cleanup:
> VIR_FREE(parent);
> - xmlXPathFreeContext(ctxt);
> - xmlFreeDoc(xmldoc);
> - VIR_FREE(xml);
> if (snapshot)
> virDomainSnapshotFree(snapshot);
> if (dom)
Okay, that works even if one reopen a different connection in shell mode
ACK,
Daniel
--
Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/
daniel at veillard.com | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library http://libvirt.org/
More information about the libvir-list
mailing list