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       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 nsWrapperCacheInline_h___
       8             : #define nsWrapperCacheInline_h___
       9             : 
      10             : #include "nsWrapperCache.h"
      11             : #include "js/GCAPI.h"
      12             : #include "js/TracingAPI.h"
      13             : 
      14             : inline JSObject*
      15       35645 : nsWrapperCache::GetWrapperPreserveColor() const
      16             : {
      17       35645 :   JSObject* obj = mWrapper;
      18       35645 :   if (obj && js::gc::EdgeNeedsSweepUnbarriered(&obj)) {
      19             :     // The object has been found to be dead and is in the process of being
      20             :     // finalized, so don't let the caller see it. As an optimisation, remove it
      21             :     // from the cache so we don't have to do this check in future.
      22           0 :     const_cast<nsWrapperCache*>(this)->ClearWrapper();
      23           0 :     return nullptr;
      24             :   }
      25       35646 :   MOZ_ASSERT(obj == mWrapper);
      26       35646 :   return obj;
      27             : }
      28             : 
      29             : inline JSObject*
      30       17739 : nsWrapperCache::GetWrapper() const
      31             : {
      32       17739 :     JSObject* obj = GetWrapperPreserveColor();
      33       17739 :     if (obj) {
      34       10085 :       JS::ExposeObjectToActiveJS(obj);
      35             :     }
      36       17739 :     return obj;
      37             : }
      38             : 
      39             : inline bool
      40           0 : nsWrapperCache::HasKnownLiveWrapper() const
      41             : {
      42             :   // If we have a wrapper and it's not gray in the GC-marking sense, that means
      43             :   // that we can't be cycle-collected.  That's because the wrapper is being kept
      44             :   // alive by the JS engine (and not just due to being traced from some
      45             :   // cycle-collectable thing), and the wrapper holds us alive, so we know we're
      46             :   // not collectable.
      47           0 :   JSObject* o = GetWrapperPreserveColor();
      48           0 :   return o && !JS::ObjectIsMarkedGray(o);
      49             : }
      50             : 
      51             : static void
      52           0 : SearchGray(JS::GCCellPtr aGCThing, const char* aName, void* aClosure)
      53             : {
      54           0 :   bool* hasGrayObjects = static_cast<bool*>(aClosure);
      55           0 :   if (!*hasGrayObjects && aGCThing && JS::GCThingIsMarkedGray(aGCThing)) {
      56           0 :     *hasGrayObjects = true;
      57             :   }
      58           0 : }
      59             : 
      60             : inline bool
      61           0 : nsWrapperCache::HasNothingToTrace(nsISupports* aThis)
      62             : {
      63           0 :   nsXPCOMCycleCollectionParticipant* participant = nullptr;
      64           0 :   CallQueryInterface(aThis, &participant);
      65           0 :   bool hasGrayObjects = false;
      66           0 :   participant->Trace(aThis, TraceCallbackFunc(SearchGray), &hasGrayObjects);
      67           0 :   return !hasGrayObjects;
      68             : }
      69             : 
      70             : inline bool
      71           0 : nsWrapperCache::HasKnownLiveWrapperAndDoesNotNeedTracing(nsISupports* aThis)
      72             : {
      73           0 :   return HasKnownLiveWrapper() && HasNothingToTrace(aThis);
      74             : }
      75             : 
      76             : inline void
      77           0 : nsWrapperCache::MarkWrapperLive()
      78             : {
      79             :   // Just call GetWrapper and ignore the return value.  It will do the
      80             :   // gray-unmarking for us.
      81           0 :   GetWrapper();
      82           0 : }
      83             : 
      84             : #endif /* nsWrapperCache_h___ */