Bug 1946001 - Rename methods which return an independent nsFrameSelection to GetIndependentFrameSelection() r=emilio

The methods are now, `GetConstFrameSelection()` etc, but does not return
`const nsFrameSelection*`.  I believe that `GetIndependentFrameSelection()` is
clearer than the old names.

And also this patch adds `IsIndependentSelection()` and
`GetIndependentSelectionRootParentElement()` to make some callers of
`GetLimiter()` easier to read.

For the consistency, `GetLimiter()` should be renamed too, but I already have
a patch doing it in bug 1954020 and it's bigger.  Therefore, I leave it as-is
for now.

Differential Revision: https://phabricator.services.mozilla.com/D241774

dom/base/SelectionChangeEventDispatcher.cpp

@@ -126,26 +126,28 @@ void SelectionChangeEventDispatcher::OnSelectionChange(Document* aDoc,
 
   // Be aware, don't call GetTextControlFromSelectionLimiter once you might
   // run script because selection limit may have already been changed by it.
-  nsCOMPtr<nsIContent> textControl;
-  if ((maybeHasFormSelectEventListeners &&
-       (aReason & nsISelectionListener::JS_REASON)) ||
-      maybeHasSelectionChangeEventListeners) {
-    if (const nsFrameSelection* fs = aSel->GetFrameSelection()) {
-      if (nsCOMPtr<nsIContent> root = fs->GetLimiter()) {
-        textControl = root->GetClosestNativeAnonymousSubtreeRootParentOrHost();
-        MOZ_ASSERT_IF(textControl,
-                      textControl->IsTextControlElement() &&
-                          !textControl->IsInNativeAnonymousSubtree());
+  const RefPtr<Element> textControlElement = [&]() -> Element* {
+    if (!(maybeHasFormSelectEventListeners &&
+          (aReason & nsISelectionListener::JS_REASON)) &&
+        !maybeHasSelectionChangeEventListeners) {
+      return nullptr;
     }
+    const nsFrameSelection* fs = aSel->GetFrameSelection();
+    if (!fs || !fs->IsIndependentSelection()) {
+      return nullptr;
     }
-  };
+    Element* textControl = fs->GetIndependentSelectionRootParentElement();
+    MOZ_ASSERT_IF(textControl, textControl->IsTextControlElement());
+    MOZ_ASSERT_IF(textControl, !textControl->IsInNativeAnonymousSubtree());
+    return textControl;
+  }();
 
   // Selection changes with non-JS reason only cares about whether the new
   // selection is collapsed or not. See TextInputListener::OnSelectionChange.
-  if (textControl && maybeHasFormSelectEventListeners &&
+  if (textControlElement && maybeHasFormSelectEventListeners &&
       (aReason & nsISelectionListener::JS_REASON)) {
-    RefPtr<AsyncEventDispatcher> asyncDispatcher =
-        new AsyncEventDispatcher(textControl, eFormSelect, CanBubble::eYes);
+    RefPtr<AsyncEventDispatcher> asyncDispatcher = new AsyncEventDispatcher(
+        textControlElement, eFormSelect, CanBubble::eYes);
     asyncDispatcher->PostDOMEvent();
   }
 
@@ -157,13 +159,14 @@ void SelectionChangeEventDispatcher::OnSelectionChange(Document* aDoc,
   // controls, so for now we only support doing that under a pref, disabled by
   // default.
   // See https://github.com/w3c/selection-api/issues/53.
-  if (textControl &&
+  if (textControlElement &&
       !StaticPrefs::dom_select_events_textcontrols_selectionchange_enabled()) {
     return;
   }
 
-  nsINode* target =
-      textControl ? static_cast<nsINode*>(textControl.get()) : aDoc;
+  nsINode* target = textControlElement
+                        ? static_cast<nsINode*>(textControlElement.get())
+                        : aDoc;
   if (!target) {
     return;
   }
@@ -174,7 +177,7 @@ void SelectionChangeEventDispatcher::OnSelectionChange(Document* aDoc,
 
   target->SetHasScheduledSelectionChangeEvent();
 
-  CanBubble canBubble = textControl ? CanBubble::eYes : CanBubble::eNo;
+  CanBubble canBubble = textControlElement ? CanBubble::eYes : CanBubble::eNo;
   RefPtr<AsyncEventDispatcher> asyncDispatcher =
       new AsyncSelectionChangeEventDispatcher(target, eSelectionChange,
                                               canBubble);

dom/html/HTMLInputElement.cpp

@@ -2423,10 +2423,10 @@ nsISelectionController* HTMLInputElement::GetSelectionController() {
   return nullptr;
 }
 
-nsFrameSelection* HTMLInputElement::GetConstFrameSelection() {
+nsFrameSelection* HTMLInputElement::GetIndependentFrameSelection() const {
   TextControlState* state = GetEditorState();
   if (state) {
-    return state->GetConstFrameSelection();
+    return state->GetIndependentFrameSelection();
   }
   return nullptr;
 }
@@ -3105,7 +3105,7 @@ void HTMLInputElement::Select() {
   MOZ_ASSERT(state, "Single line text controls are expected to have a state");
 
   if (FocusState() != FocusTristate::eUnfocusable) {
-    RefPtr<nsFrameSelection> fs = state->GetConstFrameSelection();
+    RefPtr<nsFrameSelection> fs = state->GetIndependentFrameSelection();
     if (fs && fs->MouseDownRecorded()) {
       // This means that we're being called while the frame selection has a
       // mouse down event recorded to adjust the caret during the mouse up

dom/html/HTMLInputElement.h

@@ -241,7 +241,7 @@ class HTMLInputElement final : public TextControlElement,
   MOZ_CAN_RUN_SCRIPT TextEditor* GetTextEditor() override;
   TextEditor* GetExtantTextEditor() const override;
   nsISelectionController* GetSelectionController() override;
-  nsFrameSelection* GetConstFrameSelection() override;
+  nsFrameSelection* GetIndependentFrameSelection() const override;
   TextControlState* GetTextControlState() const override {
     return GetEditorState();
   }

dom/html/HTMLTextAreaElement.cpp

@@ -179,9 +179,9 @@ nsISelectionController* HTMLTextAreaElement::GetSelectionController() {
   return mState->GetSelectionController();
 }
 
-nsFrameSelection* HTMLTextAreaElement::GetConstFrameSelection() {
+nsFrameSelection* HTMLTextAreaElement::GetIndependentFrameSelection() const {
   MOZ_ASSERT(mState);
-  return mState->GetConstFrameSelection();
+  return mState->GetIndependentFrameSelection();
 }
 
 nsresult HTMLTextAreaElement::BindToFrame(nsTextControlFrame* aFrame) {

dom/html/HTMLTextAreaElement.h

@@ -88,7 +88,7 @@ class HTMLTextAreaElement final : public TextControlElement,
   MOZ_CAN_RUN_SCRIPT TextEditor* GetTextEditor() override;
   TextEditor* GetExtantTextEditor() const override;
   nsISelectionController* GetSelectionController() override;
-  nsFrameSelection* GetConstFrameSelection() override;
+  nsFrameSelection* GetIndependentFrameSelection() const override;
   TextControlState* GetTextControlState() const override { return mState; }
   nsresult BindToFrame(nsTextControlFrame* aFrame) override;
   MOZ_CAN_RUN_SCRIPT void UnbindFromFrame(nsTextControlFrame* aFrame) override;

dom/html/TextControlElement.h

@@ -131,7 +131,7 @@ class TextControlElement : public nsGenericHTMLFormControlElementWithState {
    */
   virtual nsISelectionController* GetSelectionController() = 0;
 
-  virtual nsFrameSelection* GetConstFrameSelection() = 0;
+  virtual nsFrameSelection* GetIndependentFrameSelection() const = 0;
 
   virtual TextControlState* GetTextControlState() const = 0;
 

dom/html/TextControlState.cpp

@@ -343,7 +343,9 @@ class TextInputSelectionController final : public nsSupportsWeakReference,
                                Element& aEditorRootAnonymousDiv);
 
   void SetScrollContainerFrame(ScrollContainerFrame* aScrollContainerFrame);
-  nsFrameSelection* GetConstFrameSelection() { return mFrameSelection; }
+  nsFrameSelection* GetIndependentFrameSelection() const {
+    return mFrameSelection;
+  }
   // Will return null if !mFrameSelection.
   Selection* GetSelection(SelectionType aSelectionType);
 
@@ -1526,8 +1528,8 @@ void TextControlState::Traverse(nsCycleCollectionTraversalCallback& cb) {
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mTextEditor)
 }
 
-nsFrameSelection* TextControlState::GetConstFrameSelection() {
-  return mSelCon ? mSelCon->GetConstFrameSelection() : nullptr;
+nsFrameSelection* TextControlState::GetIndependentFrameSelection() const {
+  return mSelCon ? mSelCon->GetIndependentFrameSelection() : nullptr;
 }
 
 TextEditor* TextControlState::GetTextEditor() {
@@ -1691,7 +1693,7 @@ nsresult TextControlState::PrepareEditor(const nsAString* aValue) {
     return NS_OK;
   }
 
-  AutoHideSelectionChanges hideSelectionChanges(GetConstFrameSelection());
+  AutoHideSelectionChanges hideSelectionChanges(GetIndependentFrameSelection());
 
   if (mHandlingState) {
     // Don't attempt to initialize recursively!

dom/html/TextControlState.h

@@ -222,7 +222,7 @@ class TextControlState final : public SupportsWeakPtr {
   MOZ_CAN_RUN_SCRIPT TextEditor* GetTextEditor();
   TextEditor* GetExtantTextEditor() const;
   nsISelectionController* GetSelectionController() const;
-  nsFrameSelection* GetConstFrameSelection();
+  nsFrameSelection* GetIndependentFrameSelection() const;
   nsresult BindToFrame(nsTextControlFrame* aFrame);
   MOZ_CAN_RUN_SCRIPT void UnbindFromFrame(nsTextControlFrame* aFrame);
   MOZ_CAN_RUN_SCRIPT nsresult PrepareEditor(const nsAString* aValue = nullptr);

layout/base/nsDocumentViewer.cpp

@@ -2871,8 +2871,8 @@ nsresult nsDocViewerFocusListener::HandleEvent(Event* aEvent) {
     if (selection != presShell->ConstFrameSelection()) {
       RefPtr<Document> doc = presShell->GetDocument();
       const bool selectionMatchesFocus =
-          selection->GetLimiter() &&
-          selection->GetLimiter()->GetChromeOnlyAccessSubtreeRootParent() ==
+          selection->IsIndependentSelection() &&
+          selection->GetIndependentSelectionRootParentElement() ==
               doc->GetUnretargetedFocusedContent();
       if (NS_WARN_IF(!selectionMatchesFocus)) {
         presShell->FrameSelectionWillLoseFocus(*selection);

layout/forms/nsTextControlFrame.cpp

@@ -288,7 +288,7 @@ nsresult nsTextControlFrame::EnsureEditorInitialized() {
     // Hide selection changes during the initialization, as webpages should not
     // be aware of these initializations
     AutoHideSelectionChanges hideSelectionChanges(
-        textControlElement->GetConstFrameSelection());
+        textControlElement->GetIndependentFrameSelection());
 
     nsAutoScriptBlocker scriptBlocker;
 

layout/forms/nsTextControlFrame.h

@@ -117,7 +117,7 @@ class nsTextControlFrame : public nsContainerFrame,
                                                   mozilla::SelectionDirection);
   NS_IMETHOD GetOwnedSelectionController(nsISelectionController** aSelCon);
   nsFrameSelection* GetOwnedFrameSelection() {
-    return ControlElement()->GetConstFrameSelection();
+    return ControlElement()->GetIndependentFrameSelection();
   }
   nsISelectionController* GetSelectionController() {
     return ControlElement()->GetSelectionController();

layout/generic/nsFrameSelection.h

@@ -291,6 +291,13 @@ class nsFrameSelection final {
     mClickSelectionType = aClickSelectionType;
   }
 
+  /**
+   * Return true if this is an instance for an independent selection.
+   * Currently, independent selection is created only in the text controls
+   * to manage selections in their native anonymous subtree.
+   */
+  [[nodiscard]] bool IsIndependentSelection() const { return !!GetLimiter(); }
+
   /**
    * Returns true if the selection was created by doubleclick or
    * long tap over a word.
@@ -822,9 +829,20 @@ class nsFrameSelection final {
    * non-nullptr only when this instance is for an independent selection of a
    * text control.  Then, this returns the editor root anonymous <div> in the
    * text control element.
+   * TODO: Rename this to GetIndependentSelectionRootElement() in bug 1954020
    */
   Element* GetLimiter() const { return mLimiters.mLimiter; }
 
+  /**
+   * Get the independent selection root parent which is usually a text control
+   * element which hosts the anonymous subtree managed by this frame selection.
+   */
+  Element* GetIndependentSelectionRootParentElement() const {
+    MOZ_DIAGNOSTIC_ASSERT(IsIndependentSelection());
+    return Element::FromNodeOrNull(
+        mLimiters.mLimiter->GetClosestNativeAnonymousSubtreeRootParentOrHost());
+  }
+
   /**
    * GetAncestorLimiter() returns the root of current selection ranges.  This is
    * typically the focused editing host unless it's the root element of the