Bug 1744573: Add infrastructure on DocAccessible to queue cache updates r=Jamie

Differential Revision: https://phabricator.services.mozilla.com/D136661

accessible/base/NotificationController.cpp

@@ -974,7 +974,7 @@ void NotificationController::WillRefresh(mozilla::TimeStamp aTime) {
   }
 
   if (IPCAccessibilityActive() && mDocument) {
-    mDocument->ProcessBoundsChanged();
+    mDocument->ProcessQueuedCacheUpdates();
   }
 
   mObservingState = eRefreshObserving;

accessible/base/nsAccessibilityService.cpp

@@ -366,8 +366,7 @@ void nsAccessibilityService::NotifyOfPossibleBoundsChange(
     if (document) {
       LocalAccessible* accessible = document->GetAccessible(aContent);
       if (accessible) {
-        document->MarkForBoundsProcessing(accessible);
-        document->Controller()->ScheduleProcessing();
+        document->QueueCacheUpdate(accessible, CacheDomain::Bounds);
       }
     }
   }

accessible/generic/DocAccessible.cpp

@@ -357,6 +357,14 @@ void DocAccessible::DocType(nsAString& aType) const {
   if (docType) docType->GetPublicId(aType);
 }
 
+void DocAccessible::QueueCacheUpdate(LocalAccessible* aAcc,
+                                     uint64_t aNewDomain) {
+  uint64_t& domain = mQueuedCacheUpdates.LookupOrInsert(aAcc, 0);
+  domain |= aNewDomain;
+
+  Controller()->ScheduleProcessing();
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // LocalAccessible
 
@@ -933,10 +941,6 @@ void DocAccessible::ContentRemoved(nsIContent* aChildNode,
   ContentRemoved(aChildNode);
 }
 
-void DocAccessible::MarkForBoundsProcessing(LocalAccessible* aAcc) {
-  mMaybeBoundsChanged.EnsureInserted(aAcc);
-}
-
 void DocAccessible::ParentChainChanged(nsIContent* aContent) {}
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -1388,16 +1392,19 @@ void DocAccessible::ProcessInvalidationList() {
   mInvalidationList.Clear();
 }
 
-void DocAccessible::ProcessBoundsChanged() {
+void DocAccessible::ProcessQueuedCacheUpdates() {
   if (!StaticPrefs::accessibility_cache_enabled_AtStartup()) {
     return;
   }
 
   nsTArray<CacheData> data;
-  for (auto* acc : mMaybeBoundsChanged) {
+  for (auto iter = mQueuedCacheUpdates.Iter(); !iter.Done(); iter.Next()) {
+    LocalAccessible* acc = iter.Key();
+    uint64_t domain = iter.UserData();
     if (!acc->IsDefunct()) {
-      RefPtr<AccAttributes> fields = acc->BundleFieldsForCache(
-          CacheDomain::Bounds, CacheUpdateType::Update);
+      RefPtr<AccAttributes> fields =
+          acc->BundleFieldsForCache(domain, CacheUpdateType::Update);
+
       if (fields->Count()) {
         data.AppendElement(CacheData(
             acc->IsDoc() ? 0 : reinterpret_cast<uint64_t>(acc->UniqueID()),
@@ -1406,7 +1413,7 @@ void DocAccessible::ProcessBoundsChanged() {
     }
   }
 
-  mMaybeBoundsChanged.Clear();
+  mQueuedCacheUpdates.Clear();
 
   if (data.Length()) {
     IPCDoc()->SendCache(CacheUpdateType::Update, data, true);

accessible/generic/DocAccessible.h

@@ -111,6 +111,17 @@ class DocAccessible : public HyperTextAccessibleWrap,
    */
   void DocType(nsAString& aType) const;
 
+  /**
+   * Adds an entry to mQueuedCacheUpdates indicating aAcc requires
+   * a cache update on domain aNewDomain. If we've already queued an update
+   * for aAcc, aNewDomain is or'd with the existing domain(s)
+   * and the map is updated. Otherwise, the entry is simply inserted.
+   * This function also schedules processing on the controller.
+   * Note that this CANNOT be used for anything which fires events, since events
+   * must be fired after their associated cache update.
+   */
+  void QueueCacheUpdate(LocalAccessible* aAcc, uint64_t aNewDomain);
+
   /**
    * Return virtual cursor associated with the document.
    */
@@ -346,13 +357,6 @@ class DocAccessible : public HyperTextAccessibleWrap,
   void ContentRemoved(LocalAccessible* aAccessible);
   void ContentRemoved(nsIContent* aContentNode);
 
-  /*
-   * Add the given accessible to mMaybeBoundsChanged so we
-   * can (later) check if its bounds have changed, and update
-   * the cache appropriately.
-   */
-  void MarkForBoundsProcessing(LocalAccessible* aAcc);
-
   /**
    * Updates accessible tree when rendered text is changed.
    */
@@ -502,10 +506,10 @@ class DocAccessible : public HyperTextAccessibleWrap,
 
   /**
    * Called from NotificationController to process this doc's
-   * mMaybeBoundsChanged list. Sends a cache update for each acc in this
-   * doc whose bounds have changed since reflow.
+   * mQueuedCacheUpdates list. For each acc in the map, this function
+   * sends a cache update with its corresponding CacheDomain.
    */
-  void ProcessBoundsChanged();
+  void ProcessQueuedCacheUpdates();
 
   /**
    * Only works in content process documents.
@@ -758,6 +762,12 @@ class DocAccessible : public HyperTextAccessibleWrap,
   DocAccessibleChild* mIPCDoc;
 
   nsTHashSet<RefPtr<LocalAccessible>> mMaybeBoundsChanged;
+
+  // A hash map between LocalAccessibles and CacheDomains, tracking
+  // cache updates that have been queued during the current tick
+  // but not yet sent.
+  nsTHashMap<RefPtr<LocalAccessible>, uint64_t> mQueuedCacheUpdates;
+
   // A set of Accessibles moved during this tick. Only used in content
   // processes.
   nsTHashSet<RefPtr<LocalAccessible>> mMovedAccessibles;