[libvirt] [PATCH 2/2] qemu: Split out snapshot related functions to qemu_snapshot.c

[Daniel P. Berrange]

On Thu, Jan 03, 2013 at 10:51:09AM -0700, Eric Blake wrote:
> On 01/03/2013 09:45 AM, Peter Krempa wrote:
> > ---
> >  po/POTFILES.in           |    1 +
> >  src/Makefile.am          |    1 +
> >  src/qemu/qemu_driver.c   | 1699 +-------------------------------------------
> >  src/qemu/qemu_snapshot.c | 1752 ++++++++++++++++++++++++++++++++++++++++++++++
> >  src/qemu/qemu_snapshot.h |   38 +
> >  5 files changed, 1793 insertions(+), 1698 deletions(-)
> >  create mode 100644 src/qemu/qemu_snapshot.c
> >  create mode 100644 src/qemu/qemu_snapshot.h
> 
> Now that I've seen Dan's arguments against 1/2, I tend to agree that
> qemu_util.c doesn't make much sense.  But qemu_snapshot.c still makes
> sense, so I will still review this one.
> 
> > +++ b/src/qemu/qemu_snapshot.c
> > @@ -0,0 +1,1752 @@
> > +/*
> > + * qemu_snapshot.c: QEMU snapshot handling
> > + *
> > + * Copyright (C) 2013 Red Hat, Inc.
> 
> Same comments as in 1/2 about copying over copyright years from the
> original location.
> 
> > +
> > +#include <config.h>
> > +
> > +#include <sys/types.h>
> > +#include <sys/stat.h>
> > +#include <fcntl.h>
> > +#include <unistd.h>
> > +
> 
> And same comment about sorting includes.
> 
> > +#ifndef __QEMU_SNAPSHOT_H__
> > +# define __QEMU_SNAPSHOT_H__
> > +
> > +# include "qemu_domain.h"
> > +
> > +virDomainSnapshotPtr qemuDomainSnapshotCreateXML(virDomainPtr domain,
> > +                                                 const char *xmlDesc,
> > +                                                 unsigned int flags);
> > +
> > +int qemuDomainRevertToSnapshot(virDomainSnapshotPtr,
> > +                               unsigned int flags);
> > +
> > +int qemuDomainSnapshotDelete(virDomainSnapshotPtr snapshot,
> > +                             unsigned int flags);
> > +
> 
> Interesting subset.  Why not move any of these other snapshot-related
> driver callbacks?  qemuDomainSnapshotGetXMLDesc, qemuDomainSnapshotNum,
> qemuDomainSnapshotListNames, qemuDomainListAllSnapshots,
> qemuDomainSnapshotNumChildren, qemuDomainSnapshotListChildrenNames,
> qemuDomainSnapshotListAllChildren, qemuDomainSnapshotLookupByName,
> qemuDomainSnapshotGetParent, qemuDomainSnapshotCurrent,
> qemuDomainSnapshotIsCurrent, qemuDomainSnapshotHasMetadata

IMHO all methods which are directly part of the public API
driver struct should be in qemu_driver.c. If we want to split
code, then there should be a set of internal helpers which
those public API methods call.

eg, see how it is done for migration.

  qemu_driver.c contains qemuDomainMigratePrepare2

which in turn calls

  qemuMigrationPrepareDirect in qemu_migration.c

Basically all the qemu_driver.c code does is convert from the public
API types (virDomainPtr) into the private API types (virDomainObjPtr)
and then call the main impl code.

Daniel
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