modules/kvs: Add kvs_util_json_encoded_size()

Add new kvs_util_json_encoded_size() function determine the
size of an object consistent to the format used by kvs_util_json_dumps().

Use this function instead of fileval_big() in commit API.

Add unit tests appropriately.

src/modules/kvs/commit.c

@@ -215,19 +215,6 @@ static int store_cache (commit_t *c, int current_epoch, json_t *o,
     return rc;
 }
 
-/* -1 on error, 0 on false, 1 on true */
-static int fileval_big (json_t *value)
-{
-    char *s = json_dumps (value, JSON_ENCODE_ANY);
-    if (!s) {
-        errno = ENOMEM;
-        return -1;
-    }
-    int rc = (strlen (s) > BLOBREF_MAX_STRING_SIZE) ? 1 : 0;
-    free (s);
-    return rc;
-}
-
 /* Store DIRVAL objects, converting them to DIRREFs.
  * Store (large) FILEVAL objects, converting them to FILEREFs.
  * Return 0 on success, -1 on error
@@ -269,9 +256,10 @@ static int commit_unroll (commit_t *c, int current_epoch, json_t *dir)
             }
         }
         else if ((key_value = json_object_get (value, "FILEVAL"))) {
-            if ((ret = fileval_big (key_value)) < 0)
+            size_t size;
+            if (kvs_util_json_encoded_size (key_value, &size) < 0)
                 goto done;
-            if (ret) {
+            if (size > BLOBREF_MAX_STRING_SIZE) {
                 json_incref (key_value);
                 if ((ret = store_cache (c, current_epoch, key_value,
                                         ref, &hp)) < 0)

src/modules/kvs/kvs_util.c

@@ -62,6 +62,19 @@ char *kvs_util_json_dumps (json_t *o)
     return s;
 }
 
+int kvs_util_json_encoded_size (json_t *o, size_t *size)
+{
+    char *s = kvs_util_json_dumps (o);
+    if (!s) {
+        errno = ENOMEM;
+        return -1;
+    }
+    if (size)
+        *size = strlen (s);
+    free (s);
+    return 0;
+}
+
 int kvs_util_json_hash (const char *hash_name, json_t *o, href_t ref)
 {
     char *s;

src/modules/kvs/kvs_util.h

@@ -14,6 +14,9 @@
  */
 char *kvs_util_json_dumps (json_t *o);
 
+/* returns 0 on success, -1 on failure */
+int kvs_util_json_encoded_size (json_t *o, size_t *size);
+
 /* Calculate hash of a json object
  *
  * Returns -1 on error, 0 on success

src/modules/kvs/test/kvs_util.c

@@ -13,6 +13,7 @@ int main (int argc, char *argv[])
     json_t *obj;
     href_t ref;
     char *s1, *s2;
+    size_t size;
 
     plan (NO_PLAN);
 
@@ -43,6 +44,15 @@ int main (int argc, char *argv[])
     ok (!strcmp (s1, s2),
         "kvs_util_json_dumps dumps correct string");
 
+    ok (kvs_util_json_encoded_size (obj, NULL) == 0,
+        "kvs_util_json_encoded_size works w/ NULL size param");
+
+    ok (kvs_util_json_encoded_size (obj, &size) == 0,
+        "kvs_util_json_encoded_size works");
+
+    ok (size == strlen (s2),
+        "kvs_util_json_encoded_size returns correct size");
+
     free (s1);
     s1 = NULL;
     json_decref (obj);
@@ -57,6 +67,12 @@ int main (int argc, char *argv[])
     ok (!strcmp (s1, s2),
         "kvs_util_json_dumps works on null object");
 
+    ok (kvs_util_json_encoded_size (obj, &size) == 0,
+        "kvs_util_json_encoded_size works");
+
+    ok (size == strlen (s2),
+        "kvs_util_json_encoded_size returns correct size");
+
     free (s1);
     s1 = NULL;
     json_decref (obj);
@@ -69,9 +85,16 @@ int main (int argc, char *argv[])
     ok (!strcmp (s1, s2),
         "kvs_util_json_dumps works on NULL pointer");
 
+    ok (kvs_util_json_encoded_size (NULL, &size) == 0,
+        "kvs_util_json_encoded_size works on NULL pointer");
+
+    ok (size == strlen (s2),
+        "kvs_util_json_encoded_size returns correct size");
+
     free (s1);
     s1 = NULL;
 
+
     done_testing ();
     return (0);
 }