modules/libpref/StaticPrefsBase.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
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_StaticPrefsBase_h
   8 #define mozilla_StaticPrefsBase_h
   9
  10 #include <type_traits>
  11
  12 #include "mozilla/Atomics.h"
  13
  14 namespace mozilla {
  15
  16 class SharedPrefMapBuilder;
  17
  18 // These typedefs are for use within init/StaticPrefList*.h.
  19
  20 typedef const char* String;
  21
  22 typedef Atomic<bool, Relaxed> RelaxedAtomicBool;
  23 typedef Atomic<bool, ReleaseAcquire> ReleaseAcquireAtomicBool;
  24 typedef Atomic<bool, SequentiallyConsistent> SequentiallyConsistentAtomicBool;
  25
  26 typedef Atomic<int32_t, Relaxed> RelaxedAtomicInt32;
  27 typedef Atomic<int32_t, ReleaseAcquire> ReleaseAcquireAtomicInt32;
  28 typedef Atomic<int32_t, SequentiallyConsistent>
  29     SequentiallyConsistentAtomicInt32;
  30
  31 typedef Atomic<uint32_t, Relaxed> RelaxedAtomicUint32;
  32 typedef Atomic<uint32_t, ReleaseAcquire> ReleaseAcquireAtomicUint32;
  33 typedef Atomic<uint32_t, SequentiallyConsistent>
  34     SequentiallyConsistentAtomicUint32;
  35
  36 // XXX: Atomic<float> currently doesn't work (see bug 1552086). Once it's
  37 // supported we will be able to use Atomic<float> here.
  38 typedef std::atomic<float> AtomicFloat;
  39
  40 template <typename T>
  41 struct StripAtomicImpl {
  42   typedef T Type;
  43 };
  44
  45 template <typename T, MemoryOrdering Order>
  46 struct StripAtomicImpl<Atomic<T, Order>> {
  47   typedef T Type;
  48 };
  49
  50 template <typename T>
  51 struct StripAtomicImpl<std::atomic<T>> {
  52   typedef T Type;
  53 };
  54
  55 template <typename T>
  56 using StripAtomic = typename StripAtomicImpl<T>::Type;
  57
  58 template <typename T>
  59 struct IsAtomic : std::false_type {};
  60
  61 template <typename T, MemoryOrdering Order>
  62 struct IsAtomic<Atomic<T, Order>> : std::true_type {};
  63
  64 template <typename T>
  65 struct IsAtomic<std::atomic<T>> : std::true_type {};
  66
  67 namespace StaticPrefs {
  68
  69 void MaybeInitOncePrefs();
  70
  71 }  // namespace StaticPrefs
  72
  73 }  // namespace mozilla
  74
  75 #endif  // mozilla_StaticPrefsBase_h