1 files changed, 98 insertions, 0 deletions
diff --git a/dom/base/nsWrapperCacheInlines.h b/dom/base/nsWrapperCacheInlines.h
new file mode 100644
index 0000000000..efd0e9a7f5
--- /dev/null
+++ b/dom/base/nsWrapperCacheInlines.h
@@ -0,0 +1,98 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 "js/RootingAPI.h"
+#include "js/TracingAPI.h"
+
+inline JSObject* nsWrapperCache::GetWrapperPreserveColor() const {
+  JSObject* obj = GetWrapperMaybeDead();
+  if (obj && js::gc::EdgeNeedsSweepUnbarriered(&obj)) {
+    // The object has been found to be dead and is in the process of being
+    // finalized, so don't let the caller see it.
+    // Don't clear the cache though: this happens when a new wrapper is created
+    // for this native or when the wrapper is finalized.
+    return nullptr;
+  }
+  MOZ_ASSERT(obj == mWrapper);
+  return obj;
+}
+
+inline JSObject* nsWrapperCache::GetWrapper() const {
+  JSObject* obj = GetWrapperPreserveColor();
+  if (obj) {
+    JS::ExposeObjectToActiveJS(obj);
+  }
+  return obj;
+}
+
+inline bool nsWrapperCache::HasKnownLiveWrapper() const {
+  // If we have a wrapper and it's not gray in the GC-marking sense, that means
+  // that we can't be cycle-collected.  That's because the wrapper is being kept
+  // alive by the JS engine (and not just due to being traced from some
+  // cycle-collectable thing), and the wrapper holds us alive, so we know we're
+  // not collectable.
+  JSObject* o = GetWrapperPreserveColor();
+  return o && !JS::ObjectIsMarkedGray(o);
+}
+
+static void SearchGray(JS::GCCellPtr aGCThing, const char* aName,
+                       void* aClosure) {
+  bool* hasGrayObjects = static_cast<bool*>(aClosure);
+  if (!*hasGrayObjects && aGCThing && JS::GCThingIsMarkedGray(aGCThing)) {
+    *hasGrayObjects = true;
+  }
+}
+
+inline bool nsWrapperCache::HasNothingToTrace(nsISupports* aThis) {
+  nsXPCOMCycleCollectionParticipant* participant = nullptr;
+  CallQueryInterface(aThis, &participant);
+  bool hasGrayObjects = false;
+  participant->Trace(aThis, TraceCallbackFunc(SearchGray), &hasGrayObjects);
+  return !hasGrayObjects;
+}
+
+inline bool nsWrapperCache::HasKnownLiveWrapperAndDoesNotNeedTracing(
+    nsISupports* aThis) {
+  return HasKnownLiveWrapper() && HasNothingToTrace(aThis);
+}
+
+inline void nsWrapperCache::MarkWrapperLive() {
+  // Just call GetWrapper and ignore the return value.  It will do the
+  // gray-unmarking for us.
+  GetWrapper();
+}
+
+template <typename T>
+inline void nsWrapperCache::UpdateWrapperForNewGlobal(T* aScriptObjectHolder,
+                                                      JSObject* aNewWrapper) {
+  // If the new wrapper is in a different zone we must ensure the
+  // DropJSObjects/HoldJSObjects are called to move the holder to the new zone.
+
+  bool preserving = PreservingWrapper();
+  bool zoneChanged =
+      preserving && (JS::GetObjectZone(GetWrapperPreserveColor()) !=
+                     JS::GetObjectZone(aNewWrapper));
+
+  if (zoneChanged) {
+    ReleaseWrapper(aScriptObjectHolder);
+  } else if (preserving) {
+    SetPreservingWrapper(false);
+  }
+
+  SetWrapper(aNewWrapper);
+
+  if (zoneChanged) {
+    PreserveWrapper(aScriptObjectHolder);
+  } else if (preserving) {
+    SetPreservingWrapper(true);
+  }
+}
+
+#endif /* nsWrapperCache_h___ */