Bug 1741792 part 1: Cache the caret in the parent process using caret events. r=eeejay

As well as the caret offset, we also need to cache whether the caret is at the end of a line.
Therefore, this information has been added to caret events.

Differential Revision: https://phabricator.services.mozilla.com/D132097

accessible/base/AccEvent.cpp

@@ -244,9 +244,9 @@ already_AddRefed<nsIAccessibleEvent> a11y::MakeXPCEvent(AccEvent* aEvent) {
 
   if (eventGroup & (1 << AccEvent::eCaretMoveEvent)) {
     AccCaretMoveEvent* cm = downcast_accEvent(aEvent);
-    xpEvent = new xpcAccCaretMoveEvent(type, ToXPC(acc), ToXPCDocument(doc),
+    xpEvent = new xpcAccCaretMoveEvent(
-                                       node, fromUser, cm->GetCaretOffset(),
+        type, ToXPC(acc), ToXPCDocument(doc), node, fromUser,
-                                       cm->IsSelectionCollapsed());
+        cm->GetCaretOffset(), cm->IsSelectionCollapsed(), cm->IsAtEndOfLine());
     return xpEvent.forget();
   }
 

accessible/base/AccEvent.h

@@ -341,12 +341,13 @@ class AccReorderEvent : public AccTreeMutationEvent {
 class AccCaretMoveEvent : public AccEvent {
  public:
   AccCaretMoveEvent(LocalAccessible* aAccessible, int32_t aCaretOffset,
-                    bool aIsSelectionCollapsed,
+                    bool aIsSelectionCollapsed, bool aIsAtEndOfLine,
                     EIsFromUserInput aIsFromUserInput = eAutoDetect)
       : AccEvent(::nsIAccessibleEvent::EVENT_TEXT_CARET_MOVED, aAccessible,
                  aIsFromUserInput),
         mCaretOffset(aCaretOffset),
-        mIsSelectionCollapsed(aIsSelectionCollapsed) {}
+        mIsSelectionCollapsed(aIsSelectionCollapsed),
+        mIsAtEndOfLine(aIsAtEndOfLine) {}
   virtual ~AccCaretMoveEvent() {}
 
   // AccEvent
@@ -359,11 +360,13 @@ class AccCaretMoveEvent : public AccEvent {
   int32_t GetCaretOffset() const { return mCaretOffset; }
 
   bool IsSelectionCollapsed() const { return mIsSelectionCollapsed; }
+  bool IsAtEndOfLine() { return mIsAtEndOfLine; }
 
  private:
   int32_t mCaretOffset;
 
   bool mIsSelectionCollapsed;
+  bool mIsAtEndOfLine;
 };
 
 /**

accessible/base/SelectionManager.cpp

@@ -148,9 +148,9 @@ void SelectionManager::ProcessTextSelChangeEvent(AccEvent* aEvent) {
                                              selection->FocusOffset());
   mAccWithCaret = caretCntr;
   if (mCaretOffset != -1) {
-    RefPtr<AccCaretMoveEvent> caretMoveEvent =
+    RefPtr<AccCaretMoveEvent> caretMoveEvent = new AccCaretMoveEvent(
-        new AccCaretMoveEvent(caretCntr, mCaretOffset, selection->IsCollapsed(),
+        caretCntr, mCaretOffset, selection->IsCollapsed(),
-                              aEvent->FromUserInput());
+        caretCntr->IsCaretAtEndOfLine(), aEvent->FromUserInput());
     nsEventShell::FireEvent(caretMoveEvent);
   }
 }

accessible/generic/LocalAccessible.cpp

@@ -954,7 +954,8 @@ nsresult LocalAccessible::HandleAccEvent(AccEvent* aEvent) {
         case nsIAccessibleEvent::EVENT_TEXT_CARET_MOVED: {
           AccCaretMoveEvent* event = downcast_accEvent(aEvent);
           ipcDoc->SendCaretMoveEvent(id, event->GetCaretOffset(),
-                                     event->IsSelectionCollapsed());
+                                     event->IsSelectionCollapsed(),
+                                     event->IsAtEndOfLine());
           break;
         }
         case nsIAccessibleEvent::EVENT_TEXT_INSERTED:

accessible/interfaces/nsIAccessibleCaretMoveEvent.idl

@@ -20,4 +20,9 @@ interface nsIAccessibleCaretMoveEvent: nsIAccessibleEvent
    * Return true if there is no selection.
    */
   readonly attribute bool isSelectionCollapsed;
+
+  /**
+   * Return true if the caret is at the end of a line.
+   */
+  readonly attribute bool isAtEndOfLine;
 };

accessible/ipc/DocAccessibleParent.cpp

@@ -300,7 +300,8 @@ mozilla::ipc::IPCResult DocAccessibleParent::RecvCaretMoveEvent(
 #if defined(XP_WIN)
     const LayoutDeviceIntRect& aCaretRect,
 #endif  // defined (XP_WIN)
-    const int32_t& aOffset, const bool& aIsSelectionCollapsed) {
+    const int32_t& aOffset, const bool& aIsSelectionCollapsed,
+    const bool& aIsAtEndOfLine) {
   if (mShutdown) {
     return IPC_OK();
   }
@@ -311,6 +312,10 @@ mozilla::ipc::IPCResult DocAccessibleParent::RecvCaretMoveEvent(
     return IPC_OK();
   }
 
+  mCaretId = aID;
+  mCaretOffset = aOffset;
+  mIsCaretAtEndOfLine = aIsAtEndOfLine;
+
 #if defined(XP_WIN)
   ProxyCaretMoveEvent(proxy, aCaretRect);
 #else
@@ -326,8 +331,9 @@ mozilla::ipc::IPCResult DocAccessibleParent::RecvCaretMoveEvent(
   nsINode* node = nullptr;
   bool fromUser = true;  // XXX fix me
   uint32_t type = nsIAccessibleEvent::EVENT_TEXT_CARET_MOVED;
-  RefPtr<xpcAccCaretMoveEvent> event = new xpcAccCaretMoveEvent(
+  RefPtr<xpcAccCaretMoveEvent> event =
-      type, xpcAcc, doc, node, fromUser, aOffset, aIsSelectionCollapsed);
+      new xpcAccCaretMoveEvent(type, xpcAcc, doc, node, fromUser, aOffset,
+                               aIsSelectionCollapsed, aIsAtEndOfLine);
   nsCoreUtils::DispatchAccEvent(std::move(event));
 
   return IPC_OK();

accessible/ipc/DocAccessibleParent.h

@@ -42,7 +42,10 @@ class DocAccessibleParent : public RemoteAccessible,
         mTopLevel(false),
         mTopLevelInContentProcess(false),
         mShutdown(false),
-        mFocus(0) {
+        mFocus(0),
+        mCaretId(0),
+        mCaretOffset(-1),
+        mIsCaretAtEndOfLine(false) {
     sMaxDocID++;
     mActorID = sMaxDocID;
     MOZ_ASSERT(!LiveDocs().Get(mActorID));
@@ -103,7 +106,8 @@ class DocAccessibleParent : public RemoteAccessible,
 #if defined(XP_WIN)
       const LayoutDeviceIntRect& aCaretRect,
 #endif
-      const int32_t& aOffset, const bool& aIsSelectionCollapsed) final;
+      const int32_t& aOffset, const bool& aIsSelectionCollapsed,
+      const bool& aIsAtEndOfLine) final;
 
   virtual mozilla::ipc::IPCResult RecvTextChangeEvent(
       const uint64_t& aID, const nsString& aStr, const int32_t& aStart,
@@ -288,6 +292,25 @@ class DocAccessibleParent : public RemoteAccessible,
     return const_cast<DocAccessibleParent*>(this)->GetAccessible(mFocus);
   }
 
+  /**
+   * Get the HyperText Accessible containing the caret and the offset of the
+   * caret within. If there is no caret in this document, returns
+   * {nullptr, -1}.
+   */
+  std::pair<RemoteAccessible*, int32_t> GetCaret() const {
+    if (mCaretOffset == -1) {
+      return {nullptr, -1};
+    }
+    RemoteAccessible* acc =
+        const_cast<DocAccessibleParent*>(this)->GetAccessible(mCaretId);
+    if (!acc) {
+      return {nullptr, -1};
+    }
+    return {acc, mCaretOffset};
+  }
+
+  bool IsCaretAtEndOfLine() const { return mIsCaretAtEndOfLine; }
+
  private:
   ~DocAccessibleParent() {
     LiveDocs().Remove(mActorID);
@@ -352,6 +375,9 @@ class DocAccessibleParent : public RemoteAccessible,
   nsTHashSet<RefPtr<dom::BrowserBridgeParent>> mPendingOOPChildDocs;
 
   uint64_t mFocus;
+  uint64_t mCaretId;
+  int32_t mCaretOffset;
+  bool mIsCaretAtEndOfLine;
 
   static uint64_t sMaxDocID;
   static nsTHashMap<nsUint64HashKey, DocAccessibleParent*>& LiveDocs() {

accessible/ipc/other/PDocAccessible.ipdl

@@ -96,7 +96,8 @@ parent:
   async ShowEvent(ShowEventData data, bool aFromuser);
   async HideEvent(uint64_t aRootID, bool aFromUser);
   async StateChangeEvent(uint64_t aID, uint64_t aState, bool aEnabled);
-  async CaretMoveEvent(uint64_t aID, int32_t aOffset, bool aIsSelectionCollapsed);
+  async CaretMoveEvent(uint64_t aID, int32_t aOffset,
+                       bool aIsSelectionCollapsed, bool aIsAtEndOfLine);
   async TextChangeEvent(uint64_t aID, nsString aStr, int32_t aStart, uint32_t aLen,
                         bool aIsInsert, bool aFromUser);
   async SelectionEvent(uint64_t aID, uint64_t aWidgetID, uint32_t aType);

accessible/ipc/win/DocAccessibleChild.cpp

@@ -199,21 +199,23 @@ bool DocAccessibleChild::SendFocusEvent(const uint64_t& aID,
 
 bool DocAccessibleChild::SendCaretMoveEvent(const uint64_t& aID,
                                             const int32_t& aOffset,
-                                            const bool& aIsSelectionCollapsed) {
+                                            const bool& aIsSelectionCollapsed,
+                                            const bool& aIsAtEndOfLine) {
   return SendCaretMoveEvent(aID, GetCaretRectFor(aID), aOffset,
-                            aIsSelectionCollapsed);
+                            aIsSelectionCollapsed, aIsAtEndOfLine);
 }
 
 bool DocAccessibleChild::SendCaretMoveEvent(
     const uint64_t& aID, const LayoutDeviceIntRect& aCaretRect,
-    const int32_t& aOffset, const bool& aIsSelectionCollapsed) {
+    const int32_t& aOffset, const bool& aIsSelectionCollapsed,
+    const bool& aIsAtEndOfLine) {
   if (IsConstructedInParentProcess()) {
-    return PDocAccessibleChild::SendCaretMoveEvent(aID, aCaretRect, aOffset,
+    return PDocAccessibleChild::SendCaretMoveEvent(
-                                                   aIsSelectionCollapsed);
+        aID, aCaretRect, aOffset, aIsSelectionCollapsed, aIsAtEndOfLine);
   }
 
   PushDeferredEvent(MakeUnique<SerializedCaretMove>(
-      this, aID, aCaretRect, aOffset, aIsSelectionCollapsed));
+      this, aID, aCaretRect, aOffset, aIsSelectionCollapsed, aIsAtEndOfLine));
   return true;
 }
 

accessible/ipc/win/DocAccessibleChild.h

@@ -51,11 +51,13 @@ class DocAccessibleChild : public DocAccessibleChildBase {
   bool SendStateChangeEvent(const uint64_t& aID, const uint64_t& aState,
                             const bool& aEnabled);
   bool SendCaretMoveEvent(const uint64_t& aID, const int32_t& aOffset,
-                          const bool& aIsSelectionCollapsed);
+                          const bool& aIsSelectionCollapsed,
+                          const bool& aIsAtEndOfLine);
   bool SendCaretMoveEvent(const uint64_t& aID,
                           const LayoutDeviceIntRect& aCaretRect,
                           const int32_t& aOffset,
-                          const bool& aIsSelectionCollapsed);
+                          const bool& aIsSelectionCollapsed,
+                          const bool& aIsAtEndOfLine);
   bool SendFocusEvent(const uint64_t& aID);
   bool SendFocusEvent(const uint64_t& aID,
                       const LayoutDeviceIntRect& aCaretRect);
@@ -173,22 +175,24 @@ class DocAccessibleChild : public DocAccessibleChildBase {
   struct SerializedCaretMove final : public DeferredEvent {
     SerializedCaretMove(DocAccessibleChild* aTarget, uint64_t aID,
                         const LayoutDeviceIntRect& aCaretRect, int32_t aOffset,
-                        bool aIsSelectionCollapsed)
+                        bool aIsSelectionCollapsed, bool aIsAtEndOfLine)
         : DeferredEvent(aTarget),
           mID(aID),
           mCaretRect(aCaretRect),
           mOffset(aOffset),
-          mIsSelectionCollapsed(aIsSelectionCollapsed) {}
+          mIsSelectionCollapsed(aIsSelectionCollapsed),
+          mIsAtEndOfLine(aIsAtEndOfLine) {}
 
     void Dispatch(DocAccessibleChild* aIPCDoc) override {
-      Unused << aIPCDoc->SendCaretMoveEvent(mID, mCaretRect, mOffset,
+      Unused << aIPCDoc->SendCaretMoveEvent(
-                                            mIsSelectionCollapsed);
+          mID, mCaretRect, mOffset, mIsSelectionCollapsed, mIsAtEndOfLine);
     }
 
     uint64_t mID;
     LayoutDeviceIntRect mCaretRect;
     int32_t mOffset;
     bool mIsSelectionCollapsed;
+    bool mIsAtEndOfLine;
   };
 
   struct SerializedFocus final : public DeferredEvent {

accessible/ipc/win/PDocAccessible.ipdl

@@ -59,7 +59,8 @@ parent:
   async HideEvent(uint64_t aRootID, bool aFromUser);
   async StateChangeEvent(uint64_t aID, uint64_t aState, bool aEnabled);
   async CaretMoveEvent(uint64_t aID, LayoutDeviceIntRect aCaretRect,
-                       int32_t aOffset, bool aIsSelectionCollapsed);
+                       int32_t aOffset, bool aIsAtEndOfLine,
+                       bool aIsSelectionCollapsed);
   async TextChangeEvent(uint64_t aID, nsString aStr, int32_t aStart, uint32_t aLen,
                         bool aIsInsert, bool aFromUser);
   sync SyncTextChangeEvent(uint64_t aID, nsString aStr, int32_t aStart,