[PATCH RFC V2 06/10] libxl_json: allow basic JSON type objects generation

[Wei Liu <wei.liu2@citrix.com>]

The original logic is that basic JSON types (number, string and null)
must be an element of JSON map or array. This assumption doesn't hold
true anymore when we need to return basic JSON types.

Returning basic JSON types is required for parsing number, string and
null objects back into libxl__json_object.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 tools/libxl/libxl_json.c |   40 ++++++++++++++++++++++++++++++++--------
 1 file changed, 32 insertions(+), 8 deletions(-)

diff --git a/tools/libxl/libxl_json.c b/tools/libxl/libxl_json.c
index e2d5dbe..6b2946d 100644
--- a/tools/libxl/libxl_json.c
+++ b/tools/libxl/libxl_json.c
@@ -629,8 +629,14 @@ static int json_callback_null(void *opaque)
 
     obj = libxl__json_object_alloc(ctx->gc, JSON_NULL);
 
-    if (libxl__json_object_append_to(ctx->gc, obj, ctx->current) == -1) {
-        return 0;
+    if (ctx->current) {
+        if (libxl__json_object_append_to(ctx->gc, obj, ctx->current) == -1) {
+            return 0;
+        }
+    }
+
+    if (ctx->head == NULL) {
+        ctx->head = obj;
     }
 
     return 1;
@@ -646,8 +652,14 @@ static int json_callback_boolean(void *opaque, int boolean)
     obj = libxl__json_object_alloc(ctx->gc, JSON_BOOL);
     obj->u.b = boolean;
 
-    if (libxl__json_object_append_to(ctx->gc, obj, ctx->current) == -1) {
-        return 0;
+    if (ctx->current) {
+        if (libxl__json_object_append_to(ctx->gc, obj, ctx->current) == -1) {
+            return 0;
+        }
+    }
+
+    if (ctx->head == NULL) {
+        ctx->head = obj;
     }
 
     return 1;
@@ -703,8 +715,14 @@ error:
     obj->u.string = t;
 
 out:
-    if (libxl__json_object_append_to(ctx->gc, obj, ctx->current) == -1) {
-        return 0;
+    if (ctx->current) {
+        if (libxl__json_object_append_to(ctx->gc, obj, ctx->current) == -1) {
+            return 0;
+        }
+    }
+
+    if (ctx->head == NULL) {
+        ctx->head = obj;
     }
 
     return 1;
@@ -727,8 +745,14 @@ static int json_callback_string(void *opaque, const unsigned char *str,
     obj = libxl__json_object_alloc(ctx->gc, JSON_STRING);
     obj->u.string = t;
 
-    if (libxl__json_object_append_to(ctx->gc, obj, ctx->current) == -1) {
-        return 0;
+    if (ctx->current) {
+        if (libxl__json_object_append_to(ctx->gc, obj, ctx->current) == -1) {
+            return 0;
+        }
+    }
+
+    if (ctx->head == NULL) {
+        ctx->head = obj;
     }
 
     return 1;
-- 
1.7.10.4