ScopedPrefSetter.h

Enable keyboard shortcuts

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_gtest_ScopedPrefSetter_h

#define mozilla_gtest_ScopedPrefSetter_h

#include <initializer_list>

#include "mozilla/Assertions.h"

#include "mozilla/Attributes.h"

#include "mozilla/Preferences.h"

#include "nsTArray.h"

#include "nsThreadUtils.h"

namespace mozilla {

// Sets boolean preferences for the lifetime of the instance and restores the

// previous values on destruction, so a test does not leak its pref changes into

// later tests. Must be constructed and destroyed on the main thread.

class MOZ_RAII ScopedPrefSetter {

 public:

  struct PrefAndValue {

    const char* mPrefName;

    bool mValue;

};

  ScopedPrefSetter(const char* aPrefName, bool aValue)

      : ScopedPrefSetter({{aPrefName, aValue}}) {}

  explicit ScopedPrefSetter(std::initializer_list<PrefAndValue> aPrefs) {

    MOZ_ASSERT(NS_IsMainThread());

    mOriginalValues.SetCapacity(aPrefs.size());

    for (const auto& pref : aPrefs) {

      mOriginalValues.AppendElement(PrefAndValue{

          pref.mPrefName, Preferences::GetBool(pref.mPrefName, false)});

      Preferences::SetBool(pref.mPrefName, pref.mValue);

  ~ScopedPrefSetter() {

    MOZ_ASSERT(NS_IsMainThread());

    while (!mOriginalValues.IsEmpty()) {

      const auto pref = mOriginalValues.PopLastElement();

      Preferences::SetBool(pref.mPrefName, pref.mValue);

  ScopedPrefSetter(const ScopedPrefSetter&) = delete;

  ScopedPrefSetter& operator=(const ScopedPrefSetter&) = delete;

  ScopedPrefSetter(ScopedPrefSetter&&) = delete;

  ScopedPrefSetter& operator=(ScopedPrefSetter&&) = delete;

 private:

  AutoTArray<PrefAndValue, 1> mOriginalValues;

};

}  // namespace mozilla

#endif  // mozilla_gtest_ScopedPrefSetter_h