dom/bindings/RootedRefPtr.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 file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 /**
   8  * An implementation of Rooted for RefPtr<T>.  This works by assuming that T has
   9  * a Trace() method defined on it which will trace whatever things inside the T
  10  * instance need tracing.
  11  *
  12  * This implementation has one serious drawback: operator= doesn't work right
  13  * because it's declared on Rooted directly and expects the type Rooted is
  14  * templated over.
  15  */
  16
  17 #ifndef mozilla_RootedRefPtr_h__
  18 #define mozilla_RootedRefPtr_h__
  19
  20 #include "mozilla/RefPtr.h"
  21 #include "js/GCPolicyAPI.h"
  22 #include "js/TypeDecls.h"
  23
  24 namespace JS {
  25 template <typename T>
  26 struct GCPolicy<RefPtr<T>> {
  27   static RefPtr<T> initial() { return RefPtr<T>(); }
  28
  29   static void trace(JSTracer* trc, RefPtr<T>* tp, const char* name) {
  30     if (*tp) {
  31       (*tp)->Trace(trc);
  32     }
  33   }
  34
  35   static bool isValid(const RefPtr<T>& v) {
  36     return !v || GCPolicy<T>::isValid(*v.get());
  37   }
  38 };
  39 }  // namespace JS
  40
  41 namespace js {
  42 template <typename T, typename Wrapper>
  43 struct WrappedPtrOperations<RefPtr<T>, Wrapper> {
  44   operator T*() const { return static_cast<const Wrapper*>(this)->get(); }
  45 };
  46 }  // namespace js
  47
  48 #endif /* mozilla_RootedRefPtr_h__ */