DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Implementation

Mercurial (ffe6cc09ccf3)

VCS Links

MatchKind

Preferences

SaveMethod

pref_initPhase

Macros

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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_Preferences_h
#define mozilla_Preferences_h

#ifndef MOZILLA_INTERNAL_API
#error "This header is only usable from within libxul (MOZILLA_INTERNAL_API)."
#endif

#include "nsIPrefService.h"
#include "nsIPrefBranch.h"
#include "nsIObserver.h"
#include "nsCOMPtr.h"
#include "nsTArray.h"
#include "nsWeakReference.h"
#include "mozilla/Atomics.h"
#include "mozilla/MemoryReporting.h"

class nsIFile;

#ifndef have_PrefChangedFunc_typedef
typedef void (*PrefChangedFunc)(const char *, void *);
#define have_PrefChangedFunc_typedef
#endif

#ifdef DEBUG
enum pref_initPhase {
  START,
  BEGIN_INIT_PREFS,
  END_INIT_PREFS,
  BEGIN_ALL_PREFS,
  END_ALL_PREFS
};

#define SET_PREF_PHASE(p) Preferences::SetInitPhase(p)
#else
#define SET_PREF_PHASE(p) do { } while (0)
#endif

namespace mozilla {
struct Ok;
template <typename V, typename E> class Result;
namespace dom {
class PrefSetting;
} // namespace dom

class Preferences final : public nsIPrefService,
                          public nsIObserver,
                          public nsIPrefBranch,
                          public nsSupportsWeakReference
{
public:
  typedef mozilla::dom::PrefSetting PrefSetting;

  NS_DECL_THREADSAFE_ISUPPORTS
  NS_DECL_NSIPREFSERVICE
  NS_FORWARD_NSIPREFBRANCH(sRootBranch->)
  NS_DECL_NSIOBSERVER

  Preferences();

  mozilla::Result<Ok, const char*> Init();

  /**
   * Returns true if the Preferences service is available, false otherwise.
   */
  static bool IsServiceAvailable();

  /**
   * Initialize user prefs from prefs.js/user.js
   */
  static void InitializeUserPrefs();

  /**
   * Returns the singleton instance which is addreffed.
   */
  static Preferences* GetInstanceForService();

  /**
   * Finallizes global members.
   */
  static void Shutdown();

  /**
   * Returns shared pref service instance
   * NOTE: not addreffed.
   */
  static nsIPrefService* GetService()
  {
    NS_ENSURE_TRUE(InitStaticMembers(), nullptr);
    return sPreferences;
  }

  /**
   * Returns shared pref branch instance.
   * NOTE: not addreffed.
   */
  static nsIPrefBranch* GetRootBranch()
  {
    NS_ENSURE_TRUE(InitStaticMembers(), nullptr);
    return sRootBranch;
  }

  /**
   * Returns shared default pref branch instance.
   * NOTE: not addreffed.
   */
  static nsIPrefBranch* GetDefaultRootBranch()
  {
    NS_ENSURE_TRUE(InitStaticMembers(), nullptr);
    return sDefaultRootBranch;
  }

  /**
   * Gets int or bool type pref value with default value if failed to get
   * the pref.
   */
  static bool GetBool(const char* aPref, bool aDefault = false)
  {
    bool result = aDefault;
    GetBool(aPref, &result);
    return result;
  }

  static int32_t GetInt(const char* aPref, int32_t aDefault = 0)
  {
    int32_t result = aDefault;
    GetInt(aPref, &result);
    return result;
  }

  static uint32_t GetUint(const char* aPref, uint32_t aDefault = 0)
  {
    uint32_t result = aDefault;
    GetUint(aPref, &result);
    return result;
  }

  static float GetFloat(const char* aPref, float aDefault = 0)
  {
    float result = aDefault;
    GetFloat(aPref, &result);
    return result;
  }

  /**
   * Gets int, float, or bool type pref value with raw return value of
   * nsIPrefBranch.
   *
   * @param aPref       A pref name.
   * @param aResult     Must not be nullptr.  The value is never modified
   *                    when these methods fail.
   */
  static nsresult GetBool(const char* aPref, bool* aResult);
  static nsresult GetInt(const char* aPref, int32_t* aResult);
  static nsresult GetFloat(const char* aPref, float* aResult);
  static nsresult GetUint(const char* aPref, uint32_t* aResult)
  {
    int32_t result;
    nsresult rv = GetInt(aPref, &result);
    if (NS_SUCCEEDED(rv)) {
      *aResult = static_cast<uint32_t>(result);
    }
    return rv;
  }

  /**
   * Gets string type pref value with raw return value of nsIPrefBranch.
   *
   * @param aPref       A pref name.
   * @param aResult     The value is never modified when these methods fail.
   */
  static nsresult GetCString(const char* aPref, nsACString& aResult);
  static nsresult GetString(const char* aPref, nsAString& aResult);
  static nsresult GetLocalizedCString(const char* aPref, nsACString& aResult);
  static nsresult GetLocalizedString(const char* aPref, nsAString& aResult);

  static nsresult GetComplex(const char* aPref, const nsIID &aType,
                             void** aResult);

  /**
   * Sets various type pref values.
   */
  static nsresult SetBool(const char* aPref, bool aValue);
  static nsresult SetInt(const char* aPref, int32_t aValue);
  static nsresult SetUint(const char* aPref, uint32_t aValue)
  {
    return SetInt(aPref, static_cast<int32_t>(aValue));
  }
  static nsresult SetFloat(const char* aPref, float aValue);
  static nsresult SetCString(const char* aPref, const char* aValue);
  static nsresult SetCString(const char* aPref, const nsACString &aValue);
  static nsresult SetString(const char* aPref, const char16ptr_t aValue);
  static nsresult SetString(const char* aPref, const nsAString &aValue);

  static nsresult SetComplex(const char* aPref, const nsIID &aType,
                             nsISupports* aValue);

  /**
   * Clears user set pref.
   */
  static nsresult ClearUser(const char* aPref);

  /**
   * Whether the pref has a user value or not.
   */
  static bool HasUserValue(const char* aPref);

  /**
   * Gets the type of the pref.
   */
  static int32_t GetType(const char* aPref);

  /**
   * Adds/Removes the observer for the root pref branch.
   * The observer is referenced strongly if AddStrongObserver is used.  On the
   * other hand, it is referenced weakly, if AddWeakObserver is used.
   * See nsIPrefBranch.idl for details.
   */
  static nsresult AddStrongObserver(nsIObserver* aObserver, const char* aPref);
  static nsresult AddWeakObserver(nsIObserver* aObserver, const char* aPref);
  static nsresult RemoveObserver(nsIObserver* aObserver, const char* aPref);

  /**
   * Adds/Removes two or more observers for the root pref branch.
   * Pass to aPrefs an array of const char* whose last item is nullptr.
   */
  static nsresult AddStrongObservers(nsIObserver* aObserver,
                                     const char** aPrefs);
  static nsresult AddWeakObservers(nsIObserver* aObserver,
                                   const char** aPrefs);
  static nsresult RemoveObservers(nsIObserver* aObserver,
                                  const char** aPrefs);

  /**
   * Registers/Unregisters the callback function for the aPref.
   */
  static nsresult RegisterCallback(PrefChangedFunc aCallback,
                                   const char* aPref,
                                   void* aClosure = nullptr)
  {
    return RegisterCallback(aCallback, aPref, aClosure, ExactMatch);
  }
  static nsresult UnregisterCallback(PrefChangedFunc aCallback,
                                     const char* aPref,
                                     void* aClosure = nullptr)
  {
    return UnregisterCallback(aCallback, aPref, aClosure, ExactMatch);
  }
  // Like RegisterCallback, but also calls the callback immediately for
  // initialization.
  static nsresult RegisterCallbackAndCall(PrefChangedFunc aCallback,
                                          const char* aPref,
                                          void* aClosure = nullptr)
  {
    return RegisterCallbackAndCall(aCallback, aPref, aClosure, ExactMatch);
  }

  /**
   * Like RegisterCallback, but registers a callback for a prefix of multiple
   * pref names, not a single pref name.
   */
  static nsresult RegisterPrefixCallback(PrefChangedFunc aCallback,
                                         const char* aPref,
                                         void* aClosure = nullptr)
  {
    return RegisterCallback(aCallback, aPref, aClosure, PrefixMatch);
  }

  /**
   * Like RegisterPrefixCallback, but also calls the callback immediately for
   * initialization.
   */
  static nsresult RegisterPrefixCallbackAndCall(PrefChangedFunc aCallback,
                                                const char* aPref,
                                                void* aClosure = nullptr)
  {
    return RegisterCallbackAndCall(aCallback, aPref, aClosure, PrefixMatch);
  }

  /**
   * Unregister a callback registered with RegisterPrefixCallback or
   * RegisterPrefixCallbackAndCall.
   */
  static nsresult UnregisterPrefixCallback(PrefChangedFunc aCallback,
                                           const char* aPref,
                                           void* aClosure = nullptr)
  {
    return UnregisterCallback(aCallback, aPref, aClosure, PrefixMatch);
  }

  /**
   * Adds the aVariable to cache table.  aVariable must be a pointer for a
   * static variable.  The value will be modified when the pref value is
   * changed but note that even if you modified it, the value isn't assigned to
   * the pref.
   */
  static nsresult AddBoolVarCache(bool* aVariable,
                                  const char* aPref,
                                  bool aDefault = false);
  static nsresult AddIntVarCache(int32_t* aVariable,
                                 const char* aPref,
                                 int32_t aDefault = 0);
  static nsresult AddUintVarCache(uint32_t* aVariable,
                                  const char* aPref,
                                  uint32_t aDefault = 0);
  template <MemoryOrdering Order>
  static nsresult AddAtomicUintVarCache(Atomic<uint32_t, Order>* aVariable,
                                        const char* aPref,
                                        uint32_t aDefault = 0);
  static nsresult AddFloatVarCache(float* aVariable,
                                   const char* aPref,
                                   float aDefault = 0.0f);

  /**
   * Gets the default bool, int or uint value of the pref.
   * The result is raw result of nsIPrefBranch::Get*Pref().
   * If the pref could have any value, you needed to use these methods.
   * If not so, you could use below methods.
   */
  static nsresult GetDefaultBool(const char* aPref, bool* aResult);
  static nsresult GetDefaultInt(const char* aPref, int32_t* aResult);
  static nsresult GetDefaultUint(const char* aPref, uint32_t* aResult)
  {
    return GetDefaultInt(aPref, reinterpret_cast<int32_t*>(aResult));
  }

  /**
   * Gets the default bool, int or uint value of the pref directly.
   * You can set an invalid value of the pref to aFailedResult.  If these
   * methods failed to get the default value, they would return the
   * aFailedResult value.
   */
  static bool GetDefaultBool(const char* aPref, bool aFailedResult)
  {
    bool result;
    return NS_SUCCEEDED(GetDefaultBool(aPref, &result)) ? result :
                                                          aFailedResult;
  }
  static int32_t GetDefaultInt(const char* aPref, int32_t aFailedResult)
  {
    int32_t result;
    return NS_SUCCEEDED(GetDefaultInt(aPref, &result)) ? result : aFailedResult;
  }
  static uint32_t GetDefaultUint(const char* aPref, uint32_t aFailedResult)
  {
   return static_cast<uint32_t>(
     GetDefaultInt(aPref, static_cast<int32_t>(aFailedResult)));
  }

  /**
   * Gets the default value of the char type pref.
   */
  static nsresult GetDefaultCString(const char* aPref, nsACString& aResult);
  static nsresult GetDefaultString(const char* aPref, nsAString& aResult);
  static nsresult GetDefaultLocalizedCString(const char* aPref,
                                             nsACString& aResult);
  static nsresult GetDefaultLocalizedString(const char* aPref,
                                            nsAString& aResult);

  static nsresult GetDefaultComplex(const char* aPref, const nsIID &aType,
                                    void** aResult);

  /**
   * Gets the type of the pref.
   */
  static int32_t GetDefaultType(const char* aPref);

  // Used to synchronise preferences between chrome and content processes.
  static void GetPreferences(InfallibleTArray<PrefSetting>* aPrefs);
  static void GetPreference(PrefSetting* aPref);
  static void SetPreference(const PrefSetting& aPref);

  static void SetInitPreferences(nsTArray<PrefSetting>* aPrefs);

#ifdef DEBUG
  static void SetInitPhase(pref_initPhase phase);
  static pref_initPhase InitPhase();
#endif

  static int64_t SizeOfIncludingThisAndOtherStuff(mozilla::MallocSizeOf aMallocSizeOf);

  static void DirtyCallback();

  // Explicitly choosing synchronous or asynchronous (if allowed)
  // preferences file write.  Only for the default file.  The guarantee
  // for the "blocking" is that when it returns, the file on disk
  // reflect the current state of preferences.
  nsresult SavePrefFileBlocking();
  nsresult SavePrefFileAsynchronous();

protected:
  virtual ~Preferences();

  nsresult NotifyServiceObservers(const char *aSubject);
  /**
   * Loads the prefs.js file from the profile, or creates a new one.
   *
   * @return the prefs file if successful, or nullptr on failure.
   */
  already_AddRefed<nsIFile> ReadSavedPrefs();

  /**
   * Loads the user.js file from the profile if present.
   */
  void ReadUserOverridePrefs();

  nsresult MakeBackupPrefFile(nsIFile *aFile);

  // Default pref file save can be blocking or not.
  enum class SaveMethod {
    Blocking,
    Asynchronous
  };

  // Off main thread is only respected for the default aFile value (nullptr)
  nsresult SavePrefFileInternal(nsIFile* aFile, SaveMethod aSaveMethod);
  nsresult WritePrefFile(nsIFile* aFile, SaveMethod aSaveMethod);

  // If this is false, only blocking writes, on main thread are allowed.
  bool AllowOffMainThreadSave();

  /**
   * Helpers for implementing
   * Register(Prefix)Callback/Unregister(Prefix)Callback.
   */
public:
  // Public so the ValueObserver classes can use it.
  enum MatchKind {
    PrefixMatch,
    ExactMatch,
  };

protected:
  static nsresult RegisterCallback(PrefChangedFunc aCallback,
                                   const char* aPref,
                                   void* aClosure,
                                   MatchKind aMatchKind);
  static nsresult UnregisterCallback(PrefChangedFunc aCallback,
                                     const char* aPref,
                                     void* aClosure,
                                     MatchKind aMatchKind);
  static nsresult RegisterCallbackAndCall(PrefChangedFunc aCallback,
                                          const char* aPref,
                                          void* aClosure,
                                          MatchKind aMatchKind);

private:
  nsCOMPtr<nsIFile>        mCurrentFile;
  bool                     mDirty = false;
  bool                     mProfileShutdown = false;
  // we wait a bit after prefs are dirty before writing them. In this
  // period, mDirty and mSavePending will both be true.
  bool                     mSavePending = false;

  static Preferences*      sPreferences;
  static nsIPrefBranch*    sRootBranch;
  static nsIPrefBranch*    sDefaultRootBranch;
  static bool              sShutdown;

  /**
   * Init static members.  TRUE if it succeeded.  Otherwise, FALSE.
   */
  static bool InitStaticMembers();
};

} // namespace mozilla

#endif // mozilla_Preferences_h