On 3/20/19 1:40 AM, Eric Blake wrote:
> Rather than allowing a leaky abstraction where multiple drivers have
> to open-code operations that update the relations in a
> virDomainSnapshotObjList, it is better to add accessor functions so
> that updates to relations are maintained closer to the internals. The
> goal here is to avoid access to, nchildren, first_child, or sibling
> outside of the lowest level functions, making it easier to refactor
> later on. While many of the conversions are fairly straightforward,
> the MoveChildren refactoring can be a bit interesting to follow.
Understatement ;-) Some black magic occurs
The qemuDomainSnapshotReparentChildren "snap->parent = rep->parent" gets
replaced by the new for loop... Tough to see without watching really
closely.
>
> Signed-off-by: Eric Blake <eblake@xxxxxxxxxx>
> ---
> src/conf/virdomainsnapshotobj.h | 5 ++++
> src/conf/virdomainsnapshotobjlist.h | 2 ++
> src/conf/virdomainsnapshotobj.c | 42 +++++++++++++++++++++++++++++
> src/conf/virdomainsnapshotobjlist.c | 42 ++++++++++++++++++-----------
> src/libvirt_private.syms | 3 +++
> src/qemu/qemu_driver.c | 19 +++----------
> src/test/test_driver.c | 18 +++----------
> 7 files changed, 85 insertions(+), 46 deletions(-)
>
[...]
> diff --git a/src/conf/virdomainsnapshotobj.c b/src/conf/virdomainsnapshotobj.c
> index 7f92ac21d9..d6b216c7b2 100644
> --- a/src/conf/virdomainsnapshotobj.c
> +++ b/src/conf/virdomainsnapshotobj.c
[...]
> +/* Take all children of @from and convert them into children of @to. */
> +void
> +virDomainSnapshotMoveChildren(virDomainSnapshotObjPtr from,
> + virDomainSnapshotObjPtr to)
> +{
> + virDomainSnapshotObjPtr child;
> + virDomainSnapshotObjPtr last;
> +
> + for (child = from->first_child; child; child = child->sibling) {
> + child->parent = to;
> + if (!child->sibling)
> + last = child;
> + }
> + to->nchildren += from->nchildren;
> + last->sibling = to->first_child;
Silly Coverity compiler gets quite confused thinking that @last couldn't
be set while not considering the above loop couldn't end without it
unless of course from->first_child == NULL I suppose, which would be a
different issue. Still if before the for loop we check "if
(!from->first_child) return;", then coverity is happy.
> + to->first_child = from->first_child;
> + from->nchildren = 0;
> + from->first_child = NULL;
Or virDomainSnapshotDropChildren... Still makes sense, albeit new. Seems
to make VIR_DOMAIN_SNAPSHOT_DELETE_CHILDREN_ONLY processing unnecessary.
It's not a problem but perhaps worthy of a mention.
> +}
> diff --git a/src/conf/virdomainsnapshotobjlist.c b/src/conf/virdomainsnapshotobjlist.c
> index 1eecb89a5d..9538521ab3 100644
> --- a/src/conf/virdomainsnapshotobjlist.c
> +++ b/src/conf/virdomainsnapshotobjlist.c
> @@ -72,7 +72,7 @@ virDomainSnapshotObjListParse(const char *xmlStr,
> _("incorrect flags for bulk parse"));
> return -1;
> }
> - if (snapshots->metaroot.nchildren || snapshots->current) {
> + if (virDomainSnapshotObjListSize(snapshots)) {
The only way the call could return < 0 from virHashSize is if @snapshots
== NULL... Just noting it - no problem.
> virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> _("bulk define of snapshots only possible with "
> "no existing snapshot"));
Reviewed-by: John Ferlan <jferlan@xxxxxxxxxx>
John
BTW: There could have been 3 patches out of this, but I'm fine with 1.
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