cJSON *cJSONUtils_GenerateMergePatch(cJSON *from, cJSON *to)
{
cJSON *patch = 0;
if (!to)
{
/* patch to delete everything */
return cJSON_CreateNull();
}
if ((to->type != cJSON_Object) || !from || (from->type != cJSON_Object))
{
return cJSON_Duplicate(to, 1);
}
cJSONUtils_SortObject(from);
cJSONUtils_SortObject(to);
from = from->child;
to = to->child;
patch = cJSON_CreateObject();
while (from || to)
{
int compare = from ? (to ? strcmp(from->string, to->string) : -1) : 1;
if (compare < 0)
{
/* from has a value that to doesn't have -> remove */
cJSON_AddItemToObject(patch, from->string, cJSON_CreateNull());
from = from->next;
}
else if (compare > 0)
{
/* to has a value that from doesn't have -> add to patch */
cJSON_AddItemToObject(patch, to->string, cJSON_Duplicate(to, 1));
to = to->next;
}
else
{
/* object key exists in both objects */
if (cJSONUtils_Compare(from, to))
{
/* not identical --> generate a patch */
cJSON_AddItemToObject(patch, to->string, cJSONUtils_GenerateMergePatch(from, to));
}
/* next key in the object */
from = from->next;
to = to->next;
}
}
if (!patch->child)
{
cJSON_Delete(patch);
return 0;
}
return patch;
}
static cJSON *generate_merge_patch(cJSON * const from, cJSON * const to, const cJSON_bool case_sensitive)
{
cJSON *from_child = NULL;
cJSON *to_child = NULL;
cJSON *patch = NULL;
if (to == NULL)
{
/* patch to delete everything */
return cJSON_CreateNull();
}
if (!cJSON_IsObject(to) || !cJSON_IsObject(from))
{
return cJSON_Duplicate(to, 1);
}
sort_object(from, case_sensitive);
sort_object(to, case_sensitive);
from_child = from->child;
to_child = to->child;
patch = cJSON_CreateObject();
while (from_child || to_child)
{
int diff;
if (from_child != NULL)
{
if (to_child != NULL)
{
diff = strcmp(from_child->string, to_child->string);
}
else
{
diff = -1;
}
}
else
{
diff = 1;
}
if (diff < 0)
{
/* from has a value that to doesn't have -> remove */
cJSON_AddItemToObject(patch, from_child->string, cJSON_CreateNull());
from_child = from_child->next;
}
else if (diff > 0)
{
/* to has a value that from doesn't have -> add to patch */
cJSON_AddItemToObject(patch, to_child->string, cJSON_Duplicate(to_child, 1));
to_child = to_child->next;
}
else
{
/* object key exists in both objects */
if (!compare_json(from_child, to_child, case_sensitive))
{
/* not identical --> generate a patch */
cJSON_AddItemToObject(patch, to_child->string, cJSONUtils_GenerateMergePatch(from_child, to_child));
}
/* next key in the object */
from_child = from_child->next;
to_child = to_child->next;
}
}
if (patch->child == NULL)
{
/* no patch generated */
cJSON_Delete(patch);
return NULL;
}
return patch;
}
