pdns/recursordist/settings/rust/src/helpers.rs

   1 /*
   2  * This file is part of PowerDNS or dnsdist.
   3  * Copyright -- PowerDNS.COM B.V. and its contributors
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of version 2 of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * In addition, for the avoidance of any doubt, permission is granted to
  10  * link this program with OpenSSL and to (re)distribute the binaries
  11  * produced as the result of such linking.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22
  23 use std::{error::Error, fmt};
  24 use crate::ValidationError;
  25
  26 /* Helper code for validation  */
  27 impl Error for ValidationError {}
  28 impl fmt::Display for ValidationError {
  29     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
  30         write!(f, "{}", self.msg)
  31     }
  32 }
  33
  34 // Generic helpers
  35
  36 // A helper to define a function returning a constant value and an equal function as a Rust path */
  37 pub struct U64<const U: u64>;
  38 impl<const U: u64> U64<U> {
  39     pub const fn value() -> u64 {
  40         U
  41     }
  42     pub fn is_equal(v: &u64) -> bool {
  43         v == &U
  44     }
  45 }
  46
  47 // A helper to define constant value as a Rust path */
  48 pub struct Bool<const U: bool>;
  49 impl<const U: bool> Bool<U> {
  50     pub const fn value() -> bool {
  51         U
  52     }
  53 }
  54
  55 // A helper used to decide if a bool value should be skipped
  56 pub fn if_true(v: &bool) -> bool {
  57     *v
  58 }
  59
  60 /* Helper to decide if a value has a default value, as defined by Default trait */
  61 pub fn is_default<T: Default + PartialEq>(t: &T) -> bool {
  62     t == &T::default()
  63 }
  64
  65 pub const OVERRIDE_TAG: &str = "!override";
  66
  67 pub fn is_overriding(m: &serde_yaml::Mapping, key: &str) -> bool{
  68     if let Some(serde_yaml::Value::Tagged(vvv)) = m.get(key) {
  69         return vvv.tag == OVERRIDE_TAG;
  70     }
  71     false
  72 }
  73