libxl_json: Introduce libxl__json_object_to_yajl_gen.

This function converts a libxl__json_object to yajl by calling every
yajl_gen_* function on a preallocated yajl_gen hand.

This helps to integrate a json_object into an already existing
yajl_gen tree.

This function is used in a later patch.

Backported from xen-unstable patch:
: HG changeset patch
: User Anthony PERARD <anthony.perard@citrix.com>
: Date 1349693132 -3600
: Node ID 74dee58cfc0d2d6594f388db3b4d2ce91d1bb204
: Parent  3f71aab0e2774ded0c5a03436c364fb031ba9aa0
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>

2 files changed, 64 insertions, 0 deletions

diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 7dbd8af2bf..b00ff618c7 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -1539,6 +1539,9 @@ libxl__json_map_node *libxl__json_map_node_get(const libxl__json_object *o,
 _hidden const libxl__json_object *libxl__json_map_get(const char *key,
                                           const libxl__json_object *o,
                                           libxl__json_node_type expected_type);
+_hidden yajl_status libxl__json_object_to_yajl_gen(libxl__gc *gc_opt,
+                                                   yajl_gen hand,
+                                                   libxl__json_object *param);
 _hidden void libxl__json_object_free(libxl__gc *gc_opt,
                                      libxl__json_object *obj);
 
diff --git a/tools/libxl/libxl_json.c b/tools/libxl/libxl_json.c
index 98db4657b9..72b52e8105 100644
--- a/tools/libxl/libxl_json.c
+++ b/tools/libxl/libxl_json.c
@@ -381,6 +381,67 @@ const libxl__json_object *libxl__json_map_get(const char *key,
     return NULL;
 }
 
+yajl_status libxl__json_object_to_yajl_gen(libxl__gc *gc,
+                                           yajl_gen hand,
+                                           libxl__json_object *obj)
+{
+    int idx = 0;
+    yajl_status rc;
+
+    switch (obj->type) {
+    case JSON_NULL:
+        return yajl_gen_null(hand);
+    case JSON_BOOL:
+        return yajl_gen_bool(hand, obj->u.b);
+    case JSON_INTEGER:
+        return yajl_gen_integer(hand, obj->u.i);
+    case JSON_DOUBLE:
+        return yajl_gen_double(hand, obj->u.d);
+    case JSON_NUMBER:
+        return yajl_gen_number(hand, obj->u.string, strlen(obj->u.string));
+    case JSON_STRING:
+        return libxl__yajl_gen_asciiz(hand, obj->u.string);
+    case JSON_MAP: {
+        libxl__json_map_node *node = NULL;
+
+        rc = yajl_gen_map_open(hand);
+        if (rc != yajl_status_ok)
+            return rc;
+        for (idx = 0; idx < obj->u.map->count; idx++) {
+            if (flexarray_get(obj->u.map, idx, (void**)&node) != 0)
+                break;
+
+            rc = libxl__yajl_gen_asciiz(hand, node->map_key);
+            if (rc != yajl_status_ok)
+                return rc;
+            rc = libxl__json_object_to_yajl_gen(gc, hand, node->obj);
+            if (rc != yajl_status_ok)
+                return rc;
+        }
+        return yajl_gen_map_close(hand);
+    }
+    case JSON_ARRAY: {
+        libxl__json_object *node = NULL;
+
+        rc = yajl_gen_array_open(hand);
+        if (rc != yajl_status_ok)
+            return rc;
+        for (idx = 0; idx < obj->u.array->count; idx++) {
+            if (flexarray_get(obj->u.array, idx, (void**)&node) != 0)
+                break;
+            rc = libxl__json_object_to_yajl_gen(gc, hand, node);
+            if (rc != yajl_status_ok)
+                return rc;
+        }
+        return yajl_gen_array_close(hand);
+    }
+    case JSON_ANY:
+        /* JSON_ANY is not a valid value for obj->type. */
+        ;
+    }
+    abort();
+}
+
 
 /*
  * JSON callbacks