js/src/gc/StableCellHasher.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 gc_StableCellHasher_h
   8 #define gc_StableCellHasher_h
   9
  10 #include "js/RootingAPI.h"
  11 #include "js/TypeDecls.h"
  12
  13 // StableCellHasher itself is defined in js/public/RootingAPI.h.
  14
  15 namespace js::gc {
  16
  17 struct Cell;
  18
  19 // Gets an existing UID in |uidp| if one exists.
  20 [[nodiscard]] bool MaybeGetUniqueId(Cell* cell, uint64_t* uidp);
  21
  22 // Puts an existing UID in |uidp|, or creates a new UID for this Cell and
  23 // puts that into |uidp|. Returns false on OOM.
  24 [[nodiscard]] bool GetOrCreateUniqueId(Cell* cell, uint64_t* uidp);
  25
  26 uint64_t GetUniqueIdInfallible(Cell* cell);
  27
  28 // Return true if this cell has a UID associated with it.
  29 [[nodiscard]] bool HasUniqueId(Cell* cell);
  30
  31 // Transfer an id from another cell. This must only be called on behalf of a
  32 // moving GC. This method is infallible.
  33 void TransferUniqueId(Cell* tgt, Cell* src);
  34
  35 // Remove any unique id associated with this Cell.
  36 void RemoveUniqueId(Cell* cell);
  37
  38 // Used to restore unique ID after JSObject::swap.
  39 bool SetOrUpdateUniqueId(JSContext* cx, Cell* cell, uint64_t uid);
  40
  41 }  // namespace js::gc
  42
  43 #endif  // gc_StableCellHasher_h