From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57404) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UlDch-0007pK-Kg for qemu-devel@nongnu.org; Sat, 08 Jun 2013 03:31:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UlDce-0008DH-TV for qemu-devel@nongnu.org; Sat, 08 Jun 2013 03:31:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50900) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UlDce-0008D9-Lu for qemu-devel@nongnu.org; Sat, 08 Jun 2013 03:31:36 -0400 Date: Sat, 8 Jun 2013 15:31:32 +0800 From: Fam Zheng Message-ID: <20130608073132.GA9648@localhost.nay.redhat.com> References: <1370674687-13849-1-git-send-email-xiawenc@linux.vnet.ibm.com> <1370674687-13849-5-git-send-email-xiawenc@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1370674687-13849-5-git-send-email-xiawenc@linux.vnet.ibm.com> Subject: Re: [Qemu-devel] [PATCH 04/11] snapshot: new function bdrv_snapshot_find_by_id_and_name() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Wenchao Xia Cc: kwolf@redhat.com, phrdina@redhat.com, armbru@redhat.com, qemu-devel@nongnu.org, lcapitulino@redhat.com, stefanha@redhat.com, pbonzini@redhat.com, dietmar@proxmox.com On Sat, 06/08 14:58, Wenchao Xia wrote: > To make it clear about id and name in searching, add this API > to distinguish them. Caller can choose to search by id or name, > *errp will be set only for exception. > > Some code are modified based on Pavel's patch. > > Signed-off-by: Wenchao Xia > Signed-off-by: Pavel Hrdina > --- > block/snapshot.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++ > include/block/snapshot.h | 6 ++++ > 2 files changed, 80 insertions(+), 0 deletions(-) > > diff --git a/block/snapshot.c b/block/snapshot.c > index 6c6d9de..0a9af4e 100644 > --- a/block/snapshot.c > +++ b/block/snapshot.c > @@ -48,6 +48,80 @@ int bdrv_snapshot_find(BlockDriverState *bs, QEMUSnapshotInfo *sn_info, > return ret; > } > > +/** > + * Look up an internal snapshot by @id and @name. > + * @bs: block device to search > + * @id: unique snapshot ID, or NULL > + * @name: snapshot name, or NULL > + * @sn_info: location to store information on the snapshot found > + * @errp: location to store error, will be set only for exception > + * > + * This function will traverse snapshot list in @bs to search the matching > + * one, @id and @name are the matching condition: > + * If both @id and @name are specified, find the first one with id @id and > + * name @name. > + * If only @id is specified, find the first one with id @id. > + * If only @name is specified, find the first one with name @name. > + * if none is specified, abort(). > + * > + * Returns: true when a snapshot is found and @sn_info will be filled, false > + * when error or not found. If all operation succeed but no matching one is > + * found, @errp will NOT be set. > + */ > +bool bdrv_snapshot_find_by_id_and_name(BlockDriverState *bs, > + const char *id, > + const char *name, > + QEMUSnapshotInfo *sn_info, > + Error **errp) > +{ > + QEMUSnapshotInfo *sn_tab, *sn; > + int nb_sns, i; > + bool ret = false; > + > + nb_sns = bdrv_snapshot_list(bs, &sn_tab); > + if (nb_sns < 0) { > + error_setg_errno(errp, -nb_sns, "Failed to get a snapshot list"); > + return false; > + } else if (nb_sns == 0) { > + return false; > + } > + > + if (id && name) { > + for (i = 0; i < nb_sns; i++) { > + sn = &sn_tab[i]; > + if (!strcmp(sn->id_str, id) && !strcmp(sn->name, name)) { > + *sn_info = *sn; > + ret = true; > + break; > + } > + } > + } else if (id) { > + for (i = 0; i < nb_sns; i++) { > + sn = &sn_tab[i]; > + if (!strcmp(sn->id_str, id)) { > + *sn_info = *sn; > + ret = true; > + break; > + } > + } > + } else if (name) { > + for (i = 0; i < nb_sns; i++) { > + sn = &sn_tab[i]; > + if (!strcmp(sn->name, name)) { > + *sn_info = *sn; > + ret = true; > + break; > + } > + } > + } else { > + /* program error */ > + abort(); > + } Looks duplicated. How about: if (id || name) { for (i = 0; i < nb_sns; i++) { sn = &sn_tab[i]; if ((!id || !strcmp(sn->id_str, id)) && (!name || !strcmp(sn->name, name))) { *sn_info = *sn; ret = true; break; } } } else { abort(); } And why do we have to abort here? It is not completely nonsense to me to return first snapshot with id == NULL and name == NULL. -- Fam