js/public/WeakMapPtr.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 js_WeakMapPtr_h
   8 #define js_WeakMapPtr_h
   9
  10 #include "jstypes.h"
  11
  12 #include "js/TypeDecls.h"
  13
  14 class JS_PUBLIC_API JSTracer;
  15
  16 namespace JS {
  17
  18 // A wrapper around the internal C++ representation of SpiderMonkey WeakMaps,
  19 // usable outside the engine.
  20 //
  21 // The supported template specializations are enumerated in gc/WeakMapPtr.cpp.
  22 // If you want to use this class for a different key/value combination, add it
  23 // to the list and the compiler will generate the relevant machinery.
  24 template <typename K, typename V>
  25 class JS_PUBLIC_API WeakMapPtr {
  26  public:
  27   WeakMapPtr() : ptr(nullptr) {}
  28   bool init(JSContext* cx);
  29   bool initialized() { return ptr != nullptr; }
  30   void destroy();
  31   virtual ~WeakMapPtr() { MOZ_ASSERT(!initialized()); }
  32   void trace(JSTracer* trc);
  33
  34   V lookup(const K& key);
  35   bool put(JSContext* cx, const K& key, const V& value);
  36   V removeValue(const K& key);
  37
  38  private:
  39   void* ptr;
  40
  41   // WeakMapPtr is neither copyable nor assignable.
  42   WeakMapPtr(const WeakMapPtr& wmp) = delete;
  43   WeakMapPtr& operator=(const WeakMapPtr& wmp) = delete;
  44 };
  45
  46 } /* namespace JS */
  47
  48 #endif /* js_WeakMapPtr_h */