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| 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 // | |
| 5 // A helper class that stays in sync with a preference (bool, int, real, | |
| 6 // string or filepath). For example: | |
| 7 // | |
| 8 // class MyClass { | |
| 9 // public: | |
| 10 // MyClass(PrefService* prefs) { | |
| 11 // my_string_.Init(prefs::kHomePage, prefs); | |
| 12 // } | |
| 13 // private: | |
| 14 // StringPrefMember my_string_; | |
| 15 // }; | |
| 16 // | |
| 17 // my_string_ should stay in sync with the prefs::kHomePage pref and will | |
| 18 // update if either the pref changes or if my_string_.SetValue is called. | |
| 19 // | |
| 20 // An optional observer can be passed into the Init method which can be used to | |
| 21 // notify MyClass of changes. Note that if you use SetValue(), the observer | |
| 22 // will not be notified. | |
| 23 | |
| 24 #ifndef BASE_PREFS_PREF_MEMBER_H_ | |
| 25 #define BASE_PREFS_PREF_MEMBER_H_ | |
| 26 | |
| 27 #include <string> | |
| 28 #include <vector> | |
| 29 | |
| 30 #include "base/bind.h" | |
| 31 #include "base/callback_forward.h" | |
| 32 #include "base/files/file_path.h" | |
| 33 #include "base/logging.h" | |
| 34 #include "base/macros.h" | |
| 35 #include "base/memory/ref_counted.h" | |
| 36 #include "base/prefs/base_prefs_export.h" | |
| 37 #include "base/prefs/pref_observer.h" | |
| 38 #include "base/single_thread_task_runner.h" | |
| 39 #include "base/values.h" | |
| 40 | |
| 41 class PrefService; | |
| 42 | |
| 43 namespace subtle { | |
| 44 | |
| 45 class BASE_PREFS_EXPORT PrefMemberBase : public PrefObserver { | |
| 46 public: | |
| 47 // Type of callback you can register if you need to know the name of | |
| 48 // the pref that is changing. | |
| 49 typedef base::Callback<void(const std::string&)> NamedChangeCallback; | |
| 50 | |
| 51 PrefService* prefs() { return prefs_; } | |
| 52 const PrefService* prefs() const { return prefs_; } | |
| 53 | |
| 54 protected: | |
| 55 class BASE_PREFS_EXPORT Internal | |
| 56 : public base::RefCountedThreadSafe<Internal> { | |
| 57 public: | |
| 58 Internal(); | |
| 59 | |
| 60 // Update the value, either by calling |UpdateValueInternal| directly | |
| 61 // or by dispatching to the right thread. | |
| 62 // Takes ownership of |value|. | |
| 63 void UpdateValue(base::Value* value, | |
| 64 bool is_managed, | |
| 65 bool is_user_modifiable, | |
| 66 const base::Closure& callback) const; | |
| 67 | |
| 68 void MoveToThread(scoped_refptr<base::SingleThreadTaskRunner> task_runner); | |
| 69 | |
| 70 // See PrefMember<> for description. | |
| 71 bool IsManaged() const { | |
| 72 return is_managed_; | |
| 73 } | |
| 74 | |
| 75 bool IsUserModifiable() const { | |
| 76 return is_user_modifiable_; | |
| 77 } | |
| 78 | |
| 79 protected: | |
| 80 friend class base::RefCountedThreadSafe<Internal>; | |
| 81 virtual ~Internal(); | |
| 82 | |
| 83 void CheckOnCorrectThread() const { | |
| 84 DCHECK(IsOnCorrectThread()); | |
| 85 } | |
| 86 | |
| 87 private: | |
| 88 // This method actually updates the value. It should only be called from | |
| 89 // the thread the PrefMember is on. | |
| 90 virtual bool UpdateValueInternal(const base::Value& value) const = 0; | |
| 91 | |
| 92 bool IsOnCorrectThread() const; | |
| 93 | |
| 94 scoped_refptr<base::SingleThreadTaskRunner> thread_task_runner_; | |
| 95 mutable bool is_managed_; | |
| 96 mutable bool is_user_modifiable_; | |
| 97 | |
| 98 DISALLOW_COPY_AND_ASSIGN(Internal); | |
| 99 }; | |
| 100 | |
| 101 PrefMemberBase(); | |
| 102 virtual ~PrefMemberBase(); | |
| 103 | |
| 104 // See PrefMember<> for description. | |
| 105 void Init(const std::string& pref_name, | |
| 106 PrefService* prefs, | |
| 107 const NamedChangeCallback& observer); | |
| 108 void Init(const std::string& pref_name, PrefService* prefs); | |
| 109 | |
| 110 virtual void CreateInternal() const = 0; | |
| 111 | |
| 112 // See PrefMember<> for description. | |
| 113 void Destroy(); | |
| 114 | |
| 115 void MoveToThread(scoped_refptr<base::SingleThreadTaskRunner> task_runner); | |
| 116 | |
| 117 // PrefObserver | |
| 118 void OnPreferenceChanged(PrefService* service, | |
| 119 const std::string& pref_name) override; | |
| 120 | |
| 121 void VerifyValuePrefName() const { | |
| 122 DCHECK(!pref_name_.empty()); | |
| 123 } | |
| 124 | |
| 125 // This method is used to do the actual sync with the preference. | |
| 126 // Note: it is logically const, because it doesn't modify the state | |
| 127 // seen by the outside world. It is just doing a lazy load behind the scenes. | |
| 128 void UpdateValueFromPref(const base::Closure& callback) const; | |
| 129 | |
| 130 // Verifies the preference name, and lazily loads the preference value if | |
| 131 // it hasn't been loaded yet. | |
| 132 void VerifyPref() const; | |
| 133 | |
| 134 const std::string& pref_name() const { return pref_name_; } | |
| 135 | |
| 136 virtual Internal* internal() const = 0; | |
| 137 | |
| 138 // Used to allow registering plain base::Closure callbacks. | |
| 139 static void InvokeUnnamedCallback(const base::Closure& callback, | |
| 140 const std::string& pref_name); | |
| 141 | |
| 142 private: | |
| 143 // Ordered the members to compact the class instance. | |
| 144 std::string pref_name_; | |
| 145 NamedChangeCallback observer_; | |
| 146 PrefService* prefs_; | |
| 147 | |
| 148 protected: | |
| 149 bool setting_value_; | |
| 150 }; | |
| 151 | |
| 152 // This function implements StringListPrefMember::UpdateValue(). | |
| 153 // It is exposed here for testing purposes. | |
| 154 bool BASE_PREFS_EXPORT PrefMemberVectorStringUpdate( | |
| 155 const base::Value& value, | |
| 156 std::vector<std::string>* string_vector); | |
| 157 | |
| 158 } // namespace subtle | |
| 159 | |
| 160 template <typename ValueType> | |
| 161 class PrefMember : public subtle::PrefMemberBase { | |
| 162 public: | |
| 163 // Defer initialization to an Init method so it's easy to make this class be | |
| 164 // a member variable. | |
| 165 PrefMember() {} | |
| 166 virtual ~PrefMember() {} | |
| 167 | |
| 168 // Do the actual initialization of the class. Use the two-parameter | |
| 169 // version if you don't want any notifications of changes. This | |
| 170 // method should only be called on the UI thread. | |
| 171 void Init(const std::string& pref_name, | |
| 172 PrefService* prefs, | |
| 173 const NamedChangeCallback& observer) { | |
| 174 subtle::PrefMemberBase::Init(pref_name, prefs, observer); | |
| 175 } | |
| 176 void Init(const std::string& pref_name, | |
| 177 PrefService* prefs, | |
| 178 const base::Closure& observer) { | |
| 179 subtle::PrefMemberBase::Init( | |
| 180 pref_name, prefs, | |
| 181 base::Bind(&PrefMemberBase::InvokeUnnamedCallback, observer)); | |
| 182 } | |
| 183 void Init(const std::string& pref_name, PrefService* prefs) { | |
| 184 subtle::PrefMemberBase::Init(pref_name, prefs); | |
| 185 } | |
| 186 | |
| 187 // Unsubscribes the PrefMember from the PrefService. After calling this | |
| 188 // function, the PrefMember may not be used any more on the UI thread. | |
| 189 // Assuming |MoveToThread| was previously called, |GetValue|, |IsManaged|, | |
| 190 // and |IsUserModifiable| can still be called from the other thread but | |
| 191 // the results will no longer update from the PrefService. | |
| 192 // This method should only be called on the UI thread. | |
| 193 void Destroy() { | |
| 194 subtle::PrefMemberBase::Destroy(); | |
| 195 } | |
| 196 | |
| 197 // Moves the PrefMember to another thread, allowing read accesses from there. | |
| 198 // Changes from the PrefService will be propagated asynchronously | |
| 199 // via PostTask. | |
| 200 // This method should only be used from the thread the PrefMember is currently | |
| 201 // on, which is the UI thread by default. | |
| 202 void MoveToThread(scoped_refptr<base::SingleThreadTaskRunner> task_runner) { | |
| 203 subtle::PrefMemberBase::MoveToThread(task_runner); | |
| 204 } | |
| 205 | |
| 206 // Check whether the pref is managed, i.e. controlled externally through | |
| 207 // enterprise configuration management (e.g. windows group policy). Returns | |
| 208 // false for unknown prefs. | |
| 209 // This method should only be used from the thread the PrefMember is currently | |
| 210 // on, which is the UI thread unless changed by |MoveToThread|. | |
| 211 bool IsManaged() const { | |
| 212 VerifyPref(); | |
| 213 return internal_->IsManaged(); | |
| 214 } | |
| 215 | |
| 216 // Checks whether the pref can be modified by the user. This returns false | |
| 217 // when the pref is managed by a policy or an extension, and when a command | |
| 218 // line flag overrides the pref. | |
| 219 // This method should only be used from the thread the PrefMember is currently | |
| 220 // on, which is the UI thread unless changed by |MoveToThread|. | |
| 221 bool IsUserModifiable() const { | |
| 222 VerifyPref(); | |
| 223 return internal_->IsUserModifiable(); | |
| 224 } | |
| 225 | |
| 226 // Retrieve the value of the member variable. | |
| 227 // This method should only be used from the thread the PrefMember is currently | |
| 228 // on, which is the UI thread unless changed by |MoveToThread|. | |
| 229 ValueType GetValue() const { | |
| 230 VerifyPref(); | |
| 231 return internal_->value(); | |
| 232 } | |
| 233 | |
| 234 // Provided as a convenience. | |
| 235 ValueType operator*() const { | |
| 236 return GetValue(); | |
| 237 } | |
| 238 | |
| 239 // Set the value of the member variable. | |
| 240 // This method should only be called on the UI thread. | |
| 241 void SetValue(const ValueType& value) { | |
| 242 VerifyValuePrefName(); | |
| 243 setting_value_ = true; | |
| 244 UpdatePref(value); | |
| 245 setting_value_ = false; | |
| 246 } | |
| 247 | |
| 248 // Returns the pref name. | |
| 249 const std::string& GetPrefName() const { | |
| 250 return pref_name(); | |
| 251 } | |
| 252 | |
| 253 private: | |
| 254 class Internal : public subtle::PrefMemberBase::Internal { | |
| 255 public: | |
| 256 Internal() : value_(ValueType()) {} | |
| 257 | |
| 258 ValueType value() { | |
| 259 CheckOnCorrectThread(); | |
| 260 return value_; | |
| 261 } | |
| 262 | |
| 263 protected: | |
| 264 ~Internal() override {} | |
| 265 | |
| 266 BASE_PREFS_EXPORT bool UpdateValueInternal( | |
| 267 const base::Value& value) const override; | |
| 268 | |
| 269 // We cache the value of the pref so we don't have to keep walking the pref | |
| 270 // tree. | |
| 271 mutable ValueType value_; | |
| 272 | |
| 273 private: | |
| 274 DISALLOW_COPY_AND_ASSIGN(Internal); | |
| 275 }; | |
| 276 | |
| 277 Internal* internal() const override { return internal_.get(); } | |
| 278 void CreateInternal() const override { internal_ = new Internal(); } | |
| 279 | |
| 280 // This method is used to do the actual sync with pref of the specified type. | |
| 281 void BASE_PREFS_EXPORT UpdatePref(const ValueType& value); | |
| 282 | |
| 283 mutable scoped_refptr<Internal> internal_; | |
| 284 | |
| 285 DISALLOW_COPY_AND_ASSIGN(PrefMember); | |
| 286 }; | |
| 287 | |
| 288 // Declaration of template specialization need to be repeated here | |
| 289 // specifically for each specialization (rather than just once above) | |
| 290 // or at least one of our compilers won't be happy in all cases. | |
| 291 // Specifically, it was failing on ChromeOS with a complaint about | |
| 292 // PrefMember<FilePath>::UpdateValueInternal not being defined when | |
| 293 // built in a chroot with the following parameters: | |
| 294 // | |
| 295 // FEATURES="noclean nostrip" USE="-chrome_debug -chrome_remoting | |
| 296 // -chrome_internal -chrome_pdf component_build" | |
| 297 // ~/trunk/goma/goma-wrapper cros_chrome_make --board=${BOARD} | |
| 298 // --install --runhooks | |
| 299 | |
| 300 template <> | |
| 301 BASE_PREFS_EXPORT void PrefMember<bool>::UpdatePref(const bool& value); | |
| 302 | |
| 303 template <> | |
| 304 BASE_PREFS_EXPORT bool PrefMember<bool>::Internal::UpdateValueInternal( | |
| 305 const base::Value& value) const; | |
| 306 | |
| 307 template <> | |
| 308 BASE_PREFS_EXPORT void PrefMember<int>::UpdatePref(const int& value); | |
| 309 | |
| 310 template <> | |
| 311 BASE_PREFS_EXPORT bool PrefMember<int>::Internal::UpdateValueInternal( | |
| 312 const base::Value& value) const; | |
| 313 | |
| 314 template <> | |
| 315 BASE_PREFS_EXPORT void PrefMember<double>::UpdatePref(const double& value); | |
| 316 | |
| 317 template <> | |
| 318 BASE_PREFS_EXPORT bool PrefMember<double>::Internal::UpdateValueInternal( | |
| 319 const base::Value& value) const; | |
| 320 | |
| 321 template <> | |
| 322 BASE_PREFS_EXPORT void PrefMember<std::string>::UpdatePref( | |
| 323 const std::string& value); | |
| 324 | |
| 325 template <> | |
| 326 BASE_PREFS_EXPORT bool PrefMember<std::string>::Internal::UpdateValueInternal( | |
| 327 const base::Value& value) const; | |
| 328 | |
| 329 template <> | |
| 330 BASE_PREFS_EXPORT void PrefMember<base::FilePath>::UpdatePref( | |
| 331 const base::FilePath& value); | |
| 332 | |
| 333 template <> | |
| 334 BASE_PREFS_EXPORT bool | |
| 335 PrefMember<base::FilePath>::Internal::UpdateValueInternal( | |
| 336 const base::Value& value) const; | |
| 337 | |
| 338 template <> | |
| 339 BASE_PREFS_EXPORT void PrefMember<std::vector<std::string> >::UpdatePref( | |
| 340 const std::vector<std::string>& value); | |
| 341 | |
| 342 template <> | |
| 343 BASE_PREFS_EXPORT bool | |
| 344 PrefMember<std::vector<std::string> >::Internal::UpdateValueInternal( | |
| 345 const base::Value& value) const; | |
| 346 | |
| 347 typedef PrefMember<bool> BooleanPrefMember; | |
| 348 typedef PrefMember<int> IntegerPrefMember; | |
| 349 typedef PrefMember<double> DoublePrefMember; | |
| 350 typedef PrefMember<std::string> StringPrefMember; | |
| 351 typedef PrefMember<base::FilePath> FilePathPrefMember; | |
| 352 // This preference member is expensive for large string arrays. | |
| 353 typedef PrefMember<std::vector<std::string> > StringListPrefMember; | |
| 354 | |
| 355 #endif // BASE_PREFS_PREF_MEMBER_H_ | |
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Chromium Code Reviews
Issue 1645073005:
Revert of Move base/prefs to components/prefs (Closed)
Base URL: https://chromium.googlesource.com/chromium/src.git@master