Bug 1730088 part 4: Move CaretOffset to HyperTextAccessibleBase. r=eeejay

The implementation for RemoteAccessibleBase is just a stub; we don't cache the caret yet.
However, this needs to be in HyperTextAccessibleBase because it is used by ConvertMagicOffset, which will be moved in an upcoming patch.

Differential Revision: https://phabricator.services.mozilla.com/D127209

accessible/basetypes/HyperTextAccessibleBase.h

@@ -53,6 +53,11 @@ class HyperTextAccessibleBase {
    */
   uint32_t CharacterCount() const;
 
+  /**
+   * Get caret offset, if no caret then -1.
+   */
+  virtual int32_t CaretOffset() const = 0;
+
  protected:
   virtual const Accessible* Acc() const = 0;
   Accessible* Acc() {

accessible/generic/HyperTextAccessible.h

@@ -260,7 +260,7 @@ class HyperTextAccessible : public AccessibleWrap,
   /**
    * Get/set caret offset, if no caret then -1.
    */
-  int32_t CaretOffset() const;
+  virtual int32_t CaretOffset() const override;
   void SetCaretOffset(int32_t aOffset);
 
   /**

accessible/ipc/RemoteAccessibleBase.h

@@ -223,6 +223,10 @@ class RemoteAccessibleBase : public Accessible, public HyperTextAccessibleBase {
                          : nullptr;
   }
 
+  // HyperTextAccessibleBase
+  // XXX Implement this once it's cached.
+  virtual int32_t CaretOffset() const override { return -1; }
+
  protected:
   RemoteAccessibleBase(uint64_t aID, Derived* aParent,
                        DocAccessibleParent* aDoc, role aRole, AccType aType,

accessible/ipc/RemoteAccessibleShared.h

@@ -72,7 +72,7 @@ void ScrollToPoint(uint32_t aScrollType, int32_t aX, int32_t aY);
 void Announce(const nsString& aAnnouncement, uint16_t aPriority);
 
 int32_t CaretLineNumber();
-int32_t CaretOffset();
+virtual int32_t CaretOffset() const override;
 void SetCaretOffset(int32_t aOffset);
 
 int32_t CharacterCount();

accessible/ipc/other/RemoteAccessible.cpp

@@ -154,7 +154,7 @@ int32_t RemoteAccessible::CaretLineNumber() {
   return line;
 }
 
-int32_t RemoteAccessible::CaretOffset() {
+int32_t RemoteAccessible::CaretOffset() const {
   int32_t offset = 0;
   Unused << mDoc->SendCaretOffset(mID, &offset);
   return offset;

accessible/ipc/win/RemoteAccessible.cpp

@@ -637,7 +637,11 @@ bool RemoteAccessible::RemoveFromSelection(int32_t aSelectionNum) {
   return SUCCEEDED(acc->removeSelection(static_cast<long>(aSelectionNum)));
 }
 
-int32_t RemoteAccessible::CaretOffset() {
+int32_t RemoteAccessible::CaretOffset() const {
+  if (StaticPrefs::accessibility_cache_enabled_AtStartup()) {
+    return RemoteAccessibleBase<RemoteAccessible>::CaretOffset();
+  }
+
   RefPtr<IAccessibleText> acc = QueryInterface<IAccessibleText>(this);
   if (!acc) {
     return -1;