[V2,03/11] block: add snapshot and image info query function

diff --git a/block.c b/block.c
index 5f95da5..81765a3 100644
--- a/block.c
+++ b/block.c
@@ -2846,6 +2846,123 @@  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) {
+        if (errp != NULL) {
+            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;
+}
+
+/* collect all internal snapshot info in a image for ImageInfo */
+static void collect_snapshots_info(BlockDriverState *bs,
+                                   ImageInfo *info,
+                                   Error **errp)
+{
+    SnapshotInfoList *info_list;
+
+    info_list = bdrv_query_snapshot_infolist(bs, NULL, NULL, errp);
+    if (info_list != NULL) {
+        info->has_snapshots = true;
+        info->snapshots = info_list;
+    }
+    return;
+}
+
+static void collect_image_info(BlockDriverState *bs,
+                               ImageInfo *info)
+{
+    uint64_t total_sectors;
+    char backing_filename[1024];
+    char backing_filename2[1024];
+    BlockDriverInfo bdi;
+    const char *filename;
+
+    filename = bdrv_get_filename(bs);
+    bdrv_get_geometry(bs, &total_sectors);
+
+    info->filename        = g_strdup(filename);
+    info->format          = g_strdup(bdrv_get_format_name(bs));
+    info->virtual_size    = total_sectors * 512;
+    info->actual_size     = bdrv_get_allocated_file_size(bs);
+    info->has_actual_size = info->actual_size >= 0;
+    if (bdrv_is_encrypted(bs)) {
+        info->encrypted = true;
+        info->has_encrypted = true;
+    }
+    if (bdrv_get_info(bs, &bdi) >= 0) {
+        if (bdi.cluster_size != 0) {
+            info->cluster_size = bdi.cluster_size;
+            info->has_cluster_size = true;
+        }
+        info->dirty_flag = bdi.is_dirty;
+        info->has_dirty_flag = true;
+    }
+    bdrv_get_backing_filename(bs, backing_filename, sizeof(backing_filename));
+    if (backing_filename[0] != '\0') {
+        info->backing_filename = g_strdup(backing_filename);
+        info->has_backing_filename = true;
+        bdrv_get_full_backing_filename(bs, backing_filename2,
+                                       sizeof(backing_filename2));
+
+        if (strcmp(backing_filename, backing_filename2) != 0) {
+            info->full_backing_filename = g_strdup(backing_filename2);
+            info->has_full_backing_filename = true;
+        }
+
+        if (bs->backing_format[0]) {
+            info->backing_filename_format = g_strdup(bs->backing_format);
+            info->has_backing_filename_format = true;
+        }
+    }
+}
+
+ImageInfo *bdrv_query_image_info(BlockDriverState *bs, Error **errp)
+{
+    ImageInfo *info = g_new0(ImageInfo, 1);
+    collect_image_info(bs, info);
+    collect_snapshots_info(bs, info, errp);
+    return info;
+}
+
 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 a0fc2a6..67f0d13 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -316,8 +316,17 @@  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);
+ImageInfo *bdrv_query_image_info(BlockDriverState *bs, Error **errp);
 BlockInfo *bdrv_query_info(BlockDriverState *s);
 BlockStats *bdrv_query_stats(const BlockDriverState *bs);
+
 int bdrv_can_snapshot(BlockDriverState *bs);
 int bdrv_is_snapshot(BlockDriverState *bs);
 BlockDriverState *bdrv_snapshots(void);