bug 1339128 - reference parent proxy by id r=eeejay

accessible/ipc/DocAccessibleParent.cpp

@@ -425,7 +425,7 @@ DocAccessibleParent::AddChildDoc(DocAccessibleParent* aChildDoc,
     return IPC_FAIL(this, "binding to proxy that can't be a outerDoc!");
   }
 
-  aChildDoc->mParent = outerDoc;
+  aChildDoc->SetParent(outerDoc);
   outerDoc->SetChildDoc(aChildDoc);
   mChildDocs.AppendElement(aChildDoc);
   aChildDoc->mParentDoc = this;

accessible/ipc/DocAccessibleParent.h

@@ -95,7 +95,7 @@ public:
       parent->RemoveChildDoc(this);
     }
 
-    mParent = nullptr;
+    SetParent(nullptr);
   }
 
   virtual mozilla::ipc::IPCResult RecvShutdown() override;

accessible/ipc/ProxyAccessibleBase.cpp

@@ -167,6 +167,47 @@ ProxyAccessibleBase<Derived>::OuterDocOfRemoteBrowser() const
   return chromeDoc ? chromeDoc->GetAccessible(frame) : nullptr;
 }
 
+template<class Derived>
+void
+ProxyAccessibleBase<Derived>::SetParent(Derived* aParent)
+{
+  MOZ_ASSERT(IsDoc(), "we should only reparent documents");
+  if (!aParent) {
+    mParent = kNoParent;
+  } else {
+    MOZ_ASSERT(!aParent->IsDoc());
+    mParent = aParent->ID();
+  }
+}
+
+template<class Derived>
+Derived*
+ProxyAccessibleBase<Derived>::Parent() const
+{
+  if (mParent == kNoParent) {
+    return nullptr;
+  }
+
+  // if we are not a document then are parent is another proxy in the same
+  // document.  That means we can just ask our document for the proxy with our
+  // parent id.
+  if (!IsDoc()) {
+    return Document()->GetAccessible(mParent);
+  }
+
+  // If we are a top level document then our parent is not a proxy.
+  if (AsDoc()->IsTopLevel()) {
+    return nullptr;
+  }
+
+  // Finally if we are a non top level document then our parent id is for a
+  // proxy in our parent document so get the proxy from there.
+  DocAccessibleParent* parentDoc = AsDoc()->ParentDoc();
+  MOZ_ASSERT(parentDoc);
+  MOZ_ASSERT(mParent);
+  return parentDoc->GetAccessible(mParent);
+}
+
 template class ProxyAccessibleBase<ProxyAccessible>;
 
 } // namespace a11y

accessible/ipc/ProxyAccessibleBase.h

@@ -90,7 +90,7 @@ public:
   /**
    * Return the proxy for the parent of the wrapped accessible.
    */
-  Derived* Parent() const { return mParent; }
+  Derived* Parent() const;
 
   Accessible* OuterDocOfRemoteBrowser() const;
 
@@ -158,7 +158,7 @@ protected:
   ProxyAccessibleBase(uint64_t aID, Derived* aParent,
                       DocAccessibleParent* aDoc, role aRole,
                       uint32_t aInterfaces)
-    : mParent(aParent)
+    : mParent(aParent->ID())
     , mDoc(aDoc)
     , mWrapper(0)
     , mID(aID)
@@ -172,15 +172,18 @@ protected:
   }
 
   explicit ProxyAccessibleBase(DocAccessibleParent* aThisAsDoc) :
-    mParent(nullptr), mDoc(aThisAsDoc), mWrapper(0), mID(0),
+    mParent(kNoParent), mDoc(aThisAsDoc), mWrapper(0), mID(0),
     mRole(roles::DOCUMENT), mOuterDoc(false), mIsDoc(true), mHasValue(false),
     mIsHyperLink(false), mIsHyperText(false)
   {}
 
 protected:
-  Derived* mParent;
+  void SetParent(Derived* aParent);
 
 private:
+  uintptr_t mParent;
+  static const uintptr_t kNoParent = UINTPTR_MAX;
+
   friend Derived;
 
   nsTArray<Derived*> mChildren;