Hash: API to get value string len by field name.

src/t_hash.c

@@ -130,7 +130,6 @@ robj *hashTypeGetObject(robj *o, robj *field) {
                 value = createStringObjectFromLongLong(vll);
             }
         }
-
     } else if (o->encoding == REDIS_ENCODING_HT) {
         robj *aux;
 
@@ -144,6 +143,29 @@ robj *hashTypeGetObject(robj *o, robj *field) {
     return value;
 }
 
+/* Higher level function using hashTypeGet*() to return the length of the
+ * object associated with the requested field, or 0 if the field does not
+ * exist. */
+size_t hashTypeGetValueLength(robj *o, robj *field) {
+    size_t len = 0;
+    if (o->encoding == REDIS_ENCODING_ZIPLIST) {
+        unsigned char *vstr = NULL;
+        unsigned int vlen = UINT_MAX;
+        long long vll = LLONG_MAX;
+
+        if (hashTypeGetFromZiplist(o, field, &vstr, &vlen, &vll) == 0)
+            len = vstr ? vlen : sdigits10(vll);
+    } else if (o->encoding == REDIS_ENCODING_HT) {
+        robj *aux;
+
+        if (hashTypeGetFromHashTable(o, field, &aux) == 0)
+            len = sdslen(aux->ptr);
+    } else {
+        redisPanic("Unknown hash encoding");
+    }
+    return len;
+}
+
 /* Test if the specified field exists in the given hash. Returns 1 if the field
  * exists, and 0 when it doesn't. */
 int hashTypeExists(robj *o, robj *field) {