gecko/dom/base/nsWrapperCacheInlines.h

67 lines
2.0 KiB
C

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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 nsWrapperCacheInline_h___
#define nsWrapperCacheInline_h___
#include "nsWrapperCache.h"
#include "xpcpublic.h"
#include "jsapi.h"
// We want to encode 3 bits into mWrapperPtrBits, so anything we store in it
// needs to be aligned on 8 byte boundaries.
// JS arenas are aligned on 4k boundaries and padded so that the array of
// JSObjects ends on the end of the arena. If the size of a JSObject is a
// multiple of 8 then the start of every JSObject in an arena should be aligned
// on 8 byte boundaries.
MOZ_STATIC_ASSERT(sizeof(js::shadow::Object) % 8 == 0 && sizeof(JS::Value) == 8,
"We want to rely on JSObject being aligned on 8 byte "
"boundaries.");
inline JSObject*
nsWrapperCache::GetWrapper() const
{
JSObject* obj = GetWrapperPreserveColor();
xpc_UnmarkGrayObject(obj);
return obj;
}
inline bool
nsWrapperCache::IsBlack()
{
JSObject* o = GetWrapperPreserveColor();
return o && !xpc_IsGrayGCThing(o);
}
static void
SearchGray(void* aGCThing, const char* aName, void* aClosure)
{
bool* hasGrayObjects = static_cast<bool*>(aClosure);
if (!*hasGrayObjects && aGCThing && xpc_IsGrayGCThing(aGCThing)) {
*hasGrayObjects = true;
}
}
inline bool
nsWrapperCache::IsBlackAndDoesNotNeedTracing(nsISupports* aThis)
{
if (IsBlack()) {
nsXPCOMCycleCollectionParticipant* participant = nullptr;
CallQueryInterface(aThis, &participant);
bool hasGrayObjects = false;
participant->Trace(aThis, SearchGray, &hasGrayObjects);
return !hasGrayObjects;
}
return false;
}
inline void
nsWrapperCache::TraceJSObjectFromBits(JSTracer* aTrc, const char* aName)
{
JS_CallMaskedObjectTracer(aTrc, &mWrapperPtrBits, kWrapperBitMask, aName);
}
#endif /* nsWrapperCache_h___ */