Bug 1694865 part 5: Move shutdown code into MsaaAccessible. r=morgan

Differential Revision: https://phabricator.services.mozilla.com/D112936

accessible/windows/msaa/AccessibleWrap.cpp

@@ -44,7 +44,6 @@
 #include "mozilla/Preferences.h"
 #include "mozilla/ReverseIterator.h"
 #include "mozilla/mscom/AsyncInvoker.h"
-#include "mozilla/mscom/Interceptor.h"
 
 #include "oleacc.h"
 
@@ -81,37 +80,7 @@ ITypeInfo* AccessibleWrap::gTypeInfo = nullptr;
 NS_IMPL_ISUPPORTS_INHERITED0(AccessibleWrap, LocalAccessible)
 
 void AccessibleWrap::Shutdown() {
-  if (mID != kNoID) {
-    auto doc = static_cast<DocAccessibleWrap*>(mDoc.get());
-    // Accessibles can be shut down twice in some cases. When this happens,
-    // doc will be null.
-    if (doc) {
-      doc->RemoveID(mID);
-    }
-  }
-
-  if (XRE_IsContentProcess()) {
-    // Bug 1434822: To improve performance for cross-process COM, we disable COM
-    // garbage collection. However, this means we never receive Release calls
-    // from clients, so defunct accessibles can never be deleted. Since we
-    // know when an accessible is shutting down, we can work around this by
-    // forcing COM to disconnect this object from all of its remote clients,
-    // which will cause associated references to be released.
-    IUnknown* unk = static_cast<IAccessible*>(this);
-    mscom::Interceptor::DisconnectRemotesForTarget(unk);
-    // If an accessible was retrieved via IAccessibleHypertext::hyperlink*,
-    // it will have a different Interceptor that won't be matched by the above
-    // call, even though it's the same object. Therefore, call it again with
-    // the IAccessibleHyperlink pointer. We can remove this horrible hack once
-    // bug 1440267 is fixed.
-    unk = static_cast<IAccessibleHyperlink*>(this);
-    mscom::Interceptor::DisconnectRemotesForTarget(unk);
-    for (auto& assocUnk : mAssociatedCOMObjectsForDisconnection) {
-      mscom::Interceptor::DisconnectRemotesForTarget(assocUnk);
-    }
-    mAssociatedCOMObjectsForDisconnection.Clear();
-  }
-
+  MsaaShutdown();
   LocalAccessible::Shutdown();
 }
 

accessible/windows/msaa/AccessibleWrap.h

@@ -167,20 +167,6 @@ class AccessibleWrap : public LocalAccessible, public MsaaAccessible {
   static void UpdateSystemCaretFor(RemoteAccessible* aProxy,
                                    const LayoutDeviceIntRect& aCaretRect);
 
-  /**
-   * Associate a COM object with this LocalAccessible so it will be disconnected
-   * from remote clients when this LocalAccessible shuts down.
-   * This should only be called with separate COM objects with a different
-   * IUnknown to this AccessibleWrap; e.g. IAccessibleRelation.
-   */
-  void AssociateCOMObjectForDisconnection(IUnknown* aObject) {
-    // We only need to track these for content processes because COM garbage
-    // collection is disabled there.
-    if (XRE_IsContentProcess()) {
-      mAssociatedCOMObjectsForDisconnection.AppendElement(aObject);
-    }
-  }
-
  private:
   static void UpdateSystemCaretFor(HWND aCaretWnd,
                                    const LayoutDeviceIntRect& aCaretRect);
@@ -268,8 +254,6 @@ class AccessibleWrap : public LocalAccessible, public MsaaAccessible {
   };
 
   static StaticAutoPtr<nsTArray<HandlerControllerData>> sHandlerControllers;
-
-  nsTArray<RefPtr<IUnknown>> mAssociatedCOMObjectsForDisconnection;
 };
 
 static inline AccessibleWrap* WrapperFor(const RemoteAccessible* aProxy) {

accessible/windows/msaa/MsaaAccessible.cpp

@@ -7,6 +7,7 @@
 #include "MsaaAccessible.h"
 #include "mozilla/dom/BrowserBridgeParent.h"
 #include "mozilla/dom/BrowserParent.h"
+#include "mozilla/mscom/Interceptor.h"
 #include "sdnAccessible.h"
 
 using namespace mozilla;
@@ -22,6 +23,39 @@ MsaaAccessible::~MsaaAccessible() {
   }
 }
 
+void MsaaAccessible::MsaaShutdown() {
+  if (mID != kNoID) {
+    auto doc = static_cast<DocAccessibleWrap*>(LocalAcc()->Document());
+    // Accessibles can be shut down twice in some cases. When this happens,
+    // doc will be null.
+    if (doc) {
+      doc->RemoveID(mID);
+    }
+  }
+
+  if (XRE_IsContentProcess()) {
+    // Bug 1434822: To improve performance for cross-process COM, we disable COM
+    // garbage collection. However, this means we never receive Release calls
+    // from clients, so defunct accessibles can never be deleted. Since we
+    // know when an accessible is shutting down, we can work around this by
+    // forcing COM to disconnect this object from all of its remote clients,
+    // which will cause associated references to be released.
+    IUnknown* unk = static_cast<IAccessible*>(this);
+    mscom::Interceptor::DisconnectRemotesForTarget(unk);
+    // If an accessible was retrieved via IAccessibleHypertext::hyperlink*,
+    // it will have a different Interceptor that won't be matched by the above
+    // call, even though it's the same object. Therefore, call it again with
+    // the IAccessibleHyperlink pointer. We can remove this horrible hack once
+    // bug 1440267 is fixed.
+    unk = static_cast<IAccessibleHyperlink*>(this);
+    mscom::Interceptor::DisconnectRemotesForTarget(unk);
+    for (auto& assocUnk : mAssociatedCOMObjectsForDisconnection) {
+      mscom::Interceptor::DisconnectRemotesForTarget(assocUnk);
+    }
+    mAssociatedCOMObjectsForDisconnection.Clear();
+  }
+}
+
 void MsaaAccessible::SetID(uint32_t aID) {
   MOZ_ASSERT(XRE_IsParentProcess() &&
              static_cast<AccessibleWrap*>(this)->IsProxy());

accessible/windows/msaa/MsaaAccessible.h

@@ -13,6 +13,7 @@
 #include "ia2AccessibleValue.h"
 #include "mozilla/a11y/MsaaIdGenerator.h"
 #include "mozilla/dom/ipc/IdType.h"
+#include "nsXULAppAPI.h"
 
 namespace mozilla {
 namespace a11y {
@@ -45,6 +46,22 @@ class MsaaAccessible : public ia2Accessible,
   [[nodiscard]] already_AddRefed<IAccessible> GetIAccessibleFor(
       const VARIANT& aVarChild, bool* aIsDefunct);
 
+  /**
+   * Associate a COM object with this MsaaAccessible so it will be disconnected
+   * from remote clients when this MsaaAccessible shuts down.
+   * This should only be called with separate COM objects with a different
+   * IUnknown to this MsaaAccessible; e.g. IAccessibleRelation.
+   */
+  void AssociateCOMObjectForDisconnection(IUnknown* aObject) {
+    // We only need to track these for content processes because COM garbage
+    // collection is disabled there.
+    if (XRE_IsContentProcess()) {
+      mAssociatedCOMObjectsForDisconnection.AppendElement(aObject);
+    }
+  }
+
+  void MsaaShutdown();
+
  protected:
   virtual ~MsaaAccessible();
 
@@ -60,6 +77,8 @@ class MsaaAccessible : public ia2Accessible,
    */
   [[nodiscard]] already_AddRefed<IAccessible> GetRemoteIAccessibleFor(
       const VARIANT& aVarChild);
+
+  nsTArray<RefPtr<IUnknown>> mAssociatedCOMObjectsForDisconnection;
 };
 
 }  // namespace a11y