qemu-img: refactor dump_map_entry JSON format output

Previously dump_map_entry identified whether we need to start a new JSON
array based on whether start address == 0. In this refactor we remove
this assumption as in following patches we will allow map to start from
an arbitrary position.

Reviewed-by: Eric Blake <eblake@redhat.com>
Acked-by: Mark Kanda <mark.kanda@oracle.com>
Signed-off-by: Eyal Moscovici <eyal.moscovici@oracle.com>
Message-Id: <20200513133629.18508-4-eyal.moscovici@oracle.com>
Signed-off-by: Eric Blake <eblake@redhat.com>

1 files changed, 8 insertions, 4 deletions

diff --git a/qemu-img.c b/qemu-img.c
index c88f412333..4aa9414aba 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -2902,9 +2902,8 @@ static int dump_map_entry(OutputFormat output_format, MapEntry *e,
         }
         break;
     case OFORMAT_JSON:
-        printf("%s{ \"start\": %"PRId64", \"length\": %"PRId64","
+        printf("{ \"start\": %"PRId64", \"length\": %"PRId64","
                " \"depth\": %"PRId64", \"zero\": %s, \"data\": %s",
-               (e->start == 0 ? "[" : ",\n"),
                e->start, e->length, e->depth,
                e->zero ? "true" : "false",
                e->data ? "true" : "false");
@@ -2913,8 +2912,8 @@ static int dump_map_entry(OutputFormat output_format, MapEntry *e,
         }
         putchar('}');
 
-        if (!next) {
-            printf("]\n");
+        if (next) {
+            puts(",");
         }
         break;
     }
@@ -3089,6 +3088,8 @@ static int img_map(int argc, char **argv)
 
     if (output_format == OFORMAT_HUMAN) {
         printf("%-16s%-16s%-16s%s\n", "Offset", "Length", "Mapped to", "File");
+    } else if (output_format == OFORMAT_JSON) {
+        putchar('[');
     }
 
     length = blk_getlength(blk);
@@ -3125,6 +3126,9 @@ static int img_map(int argc, char **argv)
     }
 
     ret = dump_map_entry(output_format, &curr, NULL);
+    if (output_format == OFORMAT_JSON) {
+        puts("]");
+    }
 
 out:
     blk_unref(blk);