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 #include "mozilla/DataMutex.h"
  14 #include "nsString.h"
  15
  16 namespace mozilla {
  17
  18 class SharedPrefMapBuilder;
  19
  20 // These typedefs are for use within init/StaticPrefList*.h.
  21
  22 typedef const char* String;
  23
  24 using DataMutexString = StaticDataMutex<nsCString>;
  25
  26 template <typename T>
  27 struct IsString : std::false_type {};
  28
  29 template <>
  30 struct IsString<String> : std::true_type {};
  31
  32 template <>
  33 struct IsString<DataMutexString> : std::true_type {};
  34
  35 typedef Atomic<bool, Relaxed> RelaxedAtomicBool;
  36 typedef Atomic<bool, ReleaseAcquire> ReleaseAcquireAtomicBool;
  37 typedef Atomic<bool, SequentiallyConsistent> SequentiallyConsistentAtomicBool;
  38
  39 typedef Atomic<int32_t, Relaxed> RelaxedAtomicInt32;
  40 typedef Atomic<int32_t, ReleaseAcquire> ReleaseAcquireAtomicInt32;
  41 typedef Atomic<int32_t, SequentiallyConsistent>
  42     SequentiallyConsistentAtomicInt32;
  43
  44 typedef Atomic<uint32_t, Relaxed> RelaxedAtomicUint32;
  45 typedef Atomic<uint32_t, ReleaseAcquire> ReleaseAcquireAtomicUint32;
  46 typedef Atomic<uint32_t, SequentiallyConsistent>
  47     SequentiallyConsistentAtomicUint32;
  48
  49 // XXX: Atomic<float> currently doesn't work (see bug 1552086). Once it's
  50 // supported we will be able to use Atomic<float> here.
  51 typedef std::atomic<float> AtomicFloat;
  52
  53 template <typename T>
  54 struct StripAtomicImpl {
  55   typedef T Type;
  56 };
  57
  58 template <typename T, MemoryOrdering Order>
  59 struct StripAtomicImpl<Atomic<T, Order>> {
  60   typedef T Type;
  61 };
  62
  63 template <typename T>
  64 struct StripAtomicImpl<std::atomic<T>> {
  65   typedef T Type;
  66 };
  67
  68 template <>
  69 struct StripAtomicImpl<DataMutexString> {
  70   typedef nsCString Type;
  71 };
  72
  73 template <typename T>
  74 using StripAtomic = typename StripAtomicImpl<T>::Type;
  75
  76 template <typename T>
  77 struct IsAtomic : std::false_type {};
  78
  79 template <typename T, MemoryOrdering Order>
  80 struct IsAtomic<Atomic<T, Order>> : std::true_type {};
  81
  82 template <typename T>
  83 struct IsAtomic<std::atomic<T>> : std::true_type {};
  84
  85 namespace StaticPrefs {
  86
  87 void MaybeInitOncePrefs();
  88
  89 }  // namespace StaticPrefs
  90
  91 }  // namespace mozilla
  92
  93 #endif  // mozilla_StaticPrefsBase_h