pref_member.h | Explore in Territory

// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// A helper class that stays in sync with a preference (bool, int, real,
// string or filepath).  For example:
//
// class MyClass {
//  public:
//   MyClass(PrefService* prefs) {
//     my_string_.Init(prefs::kHomePage, prefs);
//   }
//  private:
//   StringPrefMember my_string_;
// };
//
// my_string_ should stay in sync with the prefs::kHomePage pref and will
// update if either the pref changes or if my_string_.SetValue is called.
//
// An optional observer can be passed into the Init method which can be used to
// notify MyClass of changes. Note that if you use SetValue(), the observer
// will not be notified.

#ifndef COMPONENTS_PREFS_PREF_MEMBER_H_
#define COMPONENTS_PREFS_PREF_MEMBER_H_

#include <string>
#include <vector>

#include "base/check.h"
#include "base/files/file_path.h"
#include "base/functional/bind.h"
#include "base/functional/callback_forward.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/ref_counted.h"
#include "base/task/sequenced_task_runner.h"
#include "base/values.h"
#include "components/prefs/pref_observer.h"
#include "components/prefs/prefs_export.h"

class PrefService;

namespace subtle {

class COMPONENTS_PREFS_EXPORT PrefMemberBase : public PrefObserver { … };

// This function implements StringListPrefMember::UpdateValue().
// It is exposed here for testing purposes.
bool COMPONENTS_PREFS_EXPORT PrefMemberVectorStringUpdate(
    const base::Value& value,
    std::vector<std::string>* string_vector);

}  // namespace subtle

template <typename ValueType>
class PrefMember : public subtle::PrefMemberBase { … };

// Declaration of template specialization need to be repeated here
// specifically for each specialization (rather than just once above)
// or at least one of our compilers won't be happy in all cases.
// Specifically, it was failing on ChromeOS with a complaint about
// PrefMember<FilePath>::UpdateValueInternal not being defined when
// built in a chroot with the following parameters:
//
// FEATURES="noclean nostrip" USE="-chrome_debug -chrome_remoting
// -chrome_internal -chrome_pdf component_build"
// cros_chrome_make --board=${BOARD}
// --install --runhooks

template <>
COMPONENTS_PREFS_EXPORT void PrefMember<bool>::UpdatePref(const bool& value);

template <>
COMPONENTS_PREFS_EXPORT bool PrefMember<bool>::Internal::UpdateValueInternal(
    const base::Value& value) const;

template <>
COMPONENTS_PREFS_EXPORT void PrefMember<int>::UpdatePref(const int& value);

template <>
COMPONENTS_PREFS_EXPORT bool PrefMember<int>::Internal::UpdateValueInternal(
    const base::Value& value) const;

template <>
COMPONENTS_PREFS_EXPORT void
PrefMember<double>::UpdatePref(const double& value);

template <>
COMPONENTS_PREFS_EXPORT bool PrefMember<double>::Internal::UpdateValueInternal(
    const base::Value& value) const;

template <>
COMPONENTS_PREFS_EXPORT void PrefMember<std::string>::UpdatePref(
    const std::string& value);

template <>
COMPONENTS_PREFS_EXPORT bool
PrefMember<std::string>::Internal::UpdateValueInternal(
    const base::Value& value) const;

template <>
COMPONENTS_PREFS_EXPORT void PrefMember<base::FilePath>::UpdatePref(
    const base::FilePath& value);

template <>
COMPONENTS_PREFS_EXPORT bool
PrefMember<base::FilePath>::Internal::UpdateValueInternal(
    const base::Value& value) const;

template <>
COMPONENTS_PREFS_EXPORT void PrefMember<std::vector<std::string>>::UpdatePref(
    const std::vector<std::string>& value);

template <>
COMPONENTS_PREFS_EXPORT bool
PrefMember<std::vector<std::string>>::Internal::UpdateValueInternal(
    const base::Value& value) const;

BooleanPrefMember;
IntegerPrefMember;
DoublePrefMember;
StringPrefMember;
FilePathPrefMember;
// This preference member is expensive for large string arrays.
StringListPrefMember;

#endif  // COMPONENTS_PREFS_PREF_MEMBER_H_
chromium/components/prefs/pref_member.h
