Bug 1694865 part 17: Add various functions to get an MsaaAccessible/MsaaDocAccessible and use them where appropriate. r=morgan

In this patch, these new functions just static_cast, but they'll soon be returning a different object.

Differential Revision: https://phabricator.services.mozilla.com/D112952

accessible/ipc/DocAccessibleParent.cpp

@@ -140,7 +140,7 @@ uint32_t DocAccessibleParent::AddSubtree(
   ProxyCreated(newProxy);
 
 #if defined(XP_WIN)
-  WrapperFor(newProxy)->SetID(newChild.MsaaID());
+  WrapperFor(newProxy)->GetMsaa()->SetID(newChild.MsaaID());
 #endif
 
   for (uint32_t index = 0, len = mPendingChildDocs.Length(); index < len;

accessible/ipc/win/RemoteAccessible.cpp

@@ -34,15 +34,16 @@ bool RemoteAccessible::GetCOMInterface(void** aOutAccessible) const {
   if (!mCOMProxy && mSafeToRecurse) {
     // See if we can lazily obtain a COM proxy
     AccessibleWrap* wrap = WrapperFor(this);
+    MsaaAccessible* msaa = wrap->GetMsaa();
     bool isDefunct = false;
     RemoteAccessible* thisPtr = const_cast<RemoteAccessible*>(this);
     // NB: Don't pass CHILDID_SELF here, use the absolute MSAA ID. Otherwise
     // GetIAccessibleFor will recurse into this function and we will just
     // overflow the stack.
     VARIANT realId = {{{VT_I4}}};
-    realId.ulVal = wrap->GetExistingID();
+    realId.ulVal = msaa->GetExistingID();
     MOZ_DIAGNOSTIC_ASSERT(realId.ulVal != CHILDID_SELF);
-    thisPtr->mCOMProxy = wrap->GetIAccessibleFor(realId, &isDefunct);
+    thisPtr->mCOMProxy = msaa->GetIAccessibleFor(realId, &isDefunct);
   }
 
   RefPtr<IAccessible> addRefed = mCOMProxy;

accessible/windows/msaa/AccessibleWrap.h

@@ -65,6 +65,7 @@ class AccessibleWrap : public LocalAccessible, public MsaaAccessible {
    */
   bool IsRootForHWND();
 
+  MsaaAccessible* GetMsaa() { return this; }
   virtual void GetNativeInterface(void** aOutAccessible) override;
 
   static void SetHandlerControl(DWORD aPid, RefPtr<IHandlerControl> aCtrl);

accessible/windows/msaa/MsaaAccessible.cpp

@@ -40,7 +40,8 @@ void MsaaAccessible::MsaaShutdown() {
     // marked defunct. It's safe for us to call LocalAccessible::Document() here
     // regardless.
     auto localAcc = static_cast<AccessibleWrap*>(this);
-    auto doc = static_cast<DocAccessibleWrap*>(localAcc->Document());
+    DocAccessible* docAcc = localAcc->Document();
+    auto doc = docAcc ? MsaaDocAccessible::GetFrom(docAcc) : nullptr;
     // Accessibles can be shut down twice in some cases. When this happens,
     // doc will be null.
     if (doc) {
@@ -88,21 +89,20 @@ int32_t MsaaAccessible::GetChildIDFor(LocalAccessible* aAccessible) {
 
   // Chrome should use mID which has been generated by the content process.
   if (aAccessible->IsProxy()) {
-    const uint32_t id = static_cast<AccessibleWrap*>(aAccessible)->mID;
+    const uint32_t id = MsaaAccessible::GetFrom(aAccessible)->mID;
     MOZ_ASSERT(id != kNoID);
     return id;
   }
 
   if (!aAccessible->Document()) return 0;
 
-  uint32_t* id = &static_cast<AccessibleWrap*>(aAccessible)->mID;
+  uint32_t* id = &MsaaAccessible::GetFrom(aAccessible)->mID;
   if (*id != kNoID) return *id;
 
   *id = sIDGen.GetID();
 
   MOZ_ASSERT(!aAccessible->IsProxy());
-  DocAccessibleWrap* doc =
-      static_cast<DocAccessibleWrap*>(aAccessible->Document());
+  auto doc = MsaaDocAccessible::GetFrom(aAccessible->Document());
   doc->AddID(*id, static_cast<AccessibleWrap*>(aAccessible));
 
   return *id;
@@ -314,7 +314,7 @@ MsaaAccessible::ResolveChild(const VARIANT& aVarChild,
 static LocalAccessible* GetAccessibleInSubtree(DocAccessible* aDoc,
                                                uint32_t aID) {
   LocalAccessible* child =
-      static_cast<DocAccessibleWrap*>(aDoc)->GetAccessibleByID(aID);
+      MsaaDocAccessible::GetFrom(aDoc)->GetAccessibleByID(aID);
   if (child) return child;
 
   uint32_t childDocCount = aDoc->ChildDocumentCount();
@@ -558,7 +558,8 @@ already_AddRefed<IAccessible> MsaaAccessible::GetRemoteIAccessibleFor(
     RefPtr<IDispatch> disp;
     auto checkDoc = [&aVarChild,
                      &disp](DocAccessibleParent* aRemoteDoc) -> bool {
-      uint32_t remoteDocMsaaId = WrapperFor(aRemoteDoc)->GetExistingID();
+      uint32_t remoteDocMsaaId =
+          WrapperFor(aRemoteDoc)->GetMsaa()->GetExistingID();
       if (!sIDGen.IsSameContentProcessFor(aVarChild.lVal, remoteDocMsaaId)) {
         return true;  // Continue the search.
       }
@@ -618,6 +619,13 @@ ITypeInfo* MsaaAccessible::GetTI(LCID lcid) {
   return gTypeInfo;
 }
 
+/* static */
+MsaaAccessible* MsaaAccessible::GetFrom(Accessible* aAcc) {
+  // We don't support RemoteAccessible yet.
+  MOZ_ASSERT(aAcc->IsLocal());
+  return static_cast<AccessibleWrap*>(aAcc)->GetMsaa();
+}
+
 // IUnknown methods
 // XXX This delegation to AccessibleWrap is a necessary hack until we can move
 // the IUnknown implementation out of AccessibleWrap.

accessible/windows/msaa/MsaaAccessible.h

@@ -17,6 +17,7 @@
 
 namespace mozilla {
 namespace a11y {
+class Accessible;
 class AccessibleWrap;
 class LocalAccessible;
 class sdnAccessible;
@@ -66,6 +67,8 @@ class MsaaAccessible : public ia2Accessible,
 
   static IDispatch* NativeAccessible(LocalAccessible* aAccessible);
 
+  static MsaaAccessible* GetFrom(Accessible* aAcc);
+
   // IUnknown
   STDMETHODIMP QueryInterface(REFIID, void**) override;
   ULONG STDMETHODCALLTYPE AddRef() override;

accessible/windows/msaa/MsaaDocAccessible.cpp

@@ -21,6 +21,11 @@ DocAccessible* MsaaDocAccessible::DocAcc() {
   return static_cast<DocAccessible*>(acc);
 }
 
+/* static */
+MsaaDocAccessible* MsaaDocAccessible::GetFrom(DocAccessible* aDoc) {
+  return static_cast<MsaaDocAccessible*>(MsaaAccessible::GetFrom(aDoc));
+}
+
 STDMETHODIMP
 MsaaDocAccessible::get_accParent(
     /* [retval][out] */ IDispatch __RPC_FAR* __RPC_FAR* ppdispParent) {

accessible/windows/msaa/MsaaDocAccessible.h

@@ -56,6 +56,8 @@ class MsaaDocAccessible : public DocAccessible {
     return mIDToAccessibleMap.Get(aID);
   }
 
+  static MsaaDocAccessible* GetFrom(DocAccessible* aDoc);
+
  protected:
   /*
    * This provides a mapping from 32 bit id to accessible objects.

dom/ipc/BrowserParent.cpp

@@ -1198,7 +1198,7 @@ mozilla::ipc::IPCResult BrowserParent::RecvPDocAccessibleConstructor(
 
 #  ifdef XP_WIN
     MOZ_ASSERT(aDocCOMProxy.IsNull());
-    a11y::WrapperFor(doc)->SetID(aMsaaID);
+    a11y::WrapperFor(doc)->GetMsaa()->SetID(aMsaaID);
     if (a11y::nsWinUtils::IsWindowEmulationStarted()) {
       doc->SetEmulatedWindowHandle(parentDoc->GetEmulatedWindowHandle());
     }
@@ -1225,7 +1225,7 @@ mozilla::ipc::IPCResult BrowserParent::RecvPDocAccessibleConstructor(
     // before that.
     a11y::AccessibleWrap* wrapper = a11y::WrapperFor(doc);
     MOZ_ASSERT(wrapper);
-    wrapper->SetID(aMsaaID);
+    wrapper->GetMsaa()->SetID(aMsaaID);
 #  endif
     a11y::DocAccessibleParent* embedderDoc;
     uint64_t embedderID;
@@ -1259,7 +1259,7 @@ mozilla::ipc::IPCResult BrowserParent::RecvPDocAccessibleConstructor(
     doc->SetTopLevel();
     a11y::DocManager::RemoteDocAdded(doc);
 #  ifdef XP_WIN
-    a11y::WrapperFor(doc)->SetID(aMsaaID);
+    a11y::WrapperFor(doc)->GetMsaa()->SetID(aMsaaID);
     MOZ_ASSERT(!aDocCOMProxy.IsNull());
 
     RefPtr<IAccessible> proxy(aDocCOMProxy.Get());