dom/quota/AssertionsImpl.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef DOM_QUOTA_ASSERTIONSIMPL_H_
   8 #define DOM_QUOTA_ASSERTIONSIMPL_H_
   9
  10 #include "mozilla/dom/quota/Assertions.h"
  11
  12 #include <type_traits>
  13 #include "mozilla/Assertions.h"
  14
  15 namespace mozilla::dom::quota {
  16
  17 namespace detail {
  18
  19 template <typename T, bool = std::is_unsigned_v<T>>
  20 struct IntChecker {
  21   static void Assert(T aInt) {
  22     static_assert(std::is_integral_v<T>, "Not an integer!");
  23     MOZ_ASSERT(aInt >= 0);
  24   }
  25 };
  26
  27 template <typename T>
  28 struct IntChecker<T, true> {
  29   static void Assert(T aInt) {
  30     static_assert(std::is_integral_v<T>, "Not an integer!");
  31   }
  32 };
  33
  34 }  // namespace detail
  35
  36 template <typename T>
  37 void AssertNoOverflow(uint64_t aDest, T aArg) {
  38   detail::IntChecker<T>::Assert(aDest);
  39   detail::IntChecker<T>::Assert(aArg);
  40   MOZ_ASSERT(UINT64_MAX - aDest >= uint64_t(aArg));
  41 }
  42
  43 template <typename T, typename U>
  44 void AssertNoUnderflow(T aDest, U aArg) {
  45   detail::IntChecker<T>::Assert(aDest);
  46   detail::IntChecker<T>::Assert(aArg);
  47   MOZ_ASSERT(uint64_t(aDest) >= uint64_t(aArg));
  48 }
  49
  50 }  // namespace mozilla::dom::quota
  51
  52 #endif  // DOM_QUOTA_ASSERTIONSIMPL_H_