[Qemu-devel] [PATCH V4 04/13] block: add snapshot info query function bdrv_query_snapshot_infolist()

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

  This patch add function bdrv_query_snapshot_infolist(), which will
return snapshot info of an image in qmp object format. The implementation
code are mostly copied from qemu-img.c with modification to fit more
for qmp based block layer API.
  To help filter out snapshot info not needed, a call back function is
added in bdrv_query_snapshot_infolist().
  bdrv_can_read_snapshot() should be called before call this function,
to avoid got *errp set unexpectly.

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 block.c               |   46 ++++++++++++++++++++++++++++++++++++++++++++++
 include/block/block.h |    7 +++++++
 2 files changed, 53 insertions(+), 0 deletions(-)

diff --git a/block.c b/block.c
index 934bb3f..fba1be4 100644
--- a/block.c
+++ b/block.c
@@ -2842,6 +2842,52 @@ int coroutine_fn bdrv_co_is_allocated_above(BlockDriverState *top,
     return 0;
 }
 
+SnapshotInfoList *bdrv_query_snapshot_infolist(BlockDriverState *bs,
+                                               SnapshotFilterFunc filter,
+                                               void *opaque,
+                                               Error **errp)
+{
+    int i, sn_count;
+    QEMUSnapshotInfo *sn_tab = NULL;
+    SnapshotInfoList *info_list, *cur_item = NULL, *head = NULL;
+
+    sn_count = bdrv_snapshot_list(bs, &sn_tab);
+    if (sn_count < 0) {
+        /* Fix me:  set errp in bdrv_snapshot_list() instead of here */
+        error_setg(errp, "bdrv_snapshot_list: error %d\n", sn_count);
+        return NULL;
+    }
+
+    for (i = 0; i < sn_count; i++) {
+        if (filter && filter(&sn_tab[i], opaque) != 0) {
+            continue;
+        }
+
+        info_list = g_new0(SnapshotInfoList, 1);
+
+        info_list->value                = g_new0(SnapshotInfo, 1);
+        info_list->value->id            = g_strdup(sn_tab[i].id_str);
+        info_list->value->name          = g_strdup(sn_tab[i].name);
+        info_list->value->vm_state_size = sn_tab[i].vm_state_size;
+        info_list->value->date_sec      = sn_tab[i].date_sec;
+        info_list->value->date_nsec     = sn_tab[i].date_nsec;
+        info_list->value->vm_clock_sec  = sn_tab[i].vm_clock_nsec / 1000000000;
+        info_list->value->vm_clock_nsec = sn_tab[i].vm_clock_nsec % 1000000000;
+
+        /* XXX: waiting for the qapi to support qemu-queue.h types */
+        if (!cur_item) {
+            head = cur_item = info_list;
+        } else {
+            cur_item->next = info_list;
+            cur_item = info_list;
+        }
+
+    }
+
+    g_free(sn_tab);
+    return head;
+}
+
 BlockInfo *bdrv_query_info(BlockDriverState *bs)
 {
     BlockInfo *info = g_malloc0(sizeof(*info));
diff --git a/include/block/block.h b/include/block/block.h
index b4c1612..ce18d4b 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -316,6 +316,13 @@ void bdrv_get_backing_filename(BlockDriverState *bs,
                                char *filename, int filename_size);
 void bdrv_get_full_backing_filename(BlockDriverState *bs,
                                     char *dest, size_t sz);
+
+typedef int (*SnapshotFilterFunc)(const QEMUSnapshotInfo *sn, void *opaque);
+/* assume bs is already opened, use qapi_free_* to free returned value. */
+SnapshotInfoList *bdrv_query_snapshot_infolist(BlockDriverState *bs,
+                                               SnapshotFilterFunc filter,
+                                               void *opaque,
+                                               Error **errp);
 BlockInfo *bdrv_query_info(BlockDriverState *s);
 BlockStats *bdrv_query_stats(const BlockDriverState *bs);
 int bdrv_can_read_snapshot(BlockDriverState *bs);
-- 
1.7.1