Bug 1627175 - part 15: Create `HTMLEditUtils::GetFirstLeafChild()` instead of `EditorBase::GetLeftmostChild()` r=m_kato

This is used by `TextEditor::UndoAsAction()` too, so, it might be better to be in `EditorUtils`. However, it is completely designed for `HTMLEditor` and ideally, `UndoAsAction` should be overridden by `HTMLEditor` too and `TextEditor` should use faster path because of its content is in anonymous subtree. But we don't have any merit to do that instead of avoiding virtual call. Differential Revision: https://phabricator.services.mozilla.com/D74362
2020-05-08 09:49:19 +00:00 · 2020-05-08 09:49:19 +00:00 · 8c859f8589
--- a/editor/libeditor/EditorBase.cpp
+++ b/editor/libeditor/EditorBase.cpp
@ -2581,7 +2581,8 @@ nsINode* EditorBase::GetFirstEditableNode(nsINode* aRoot) {
  MOZ_ASSERT(aRoot);

  EditorType editorType = GetEditorType();
-  nsIContent* content = GetLeftmostChild(aRoot);
+  nsIContent* content =
+      HTMLEditUtils::GetFirstLeafChild(*aRoot, ChildBlockBoundary::TreatAsLeaf);
  if (content && !EditorUtils::IsEditableContent(*content, editorType)) {
    content = GetNextEditableNode(*content);
  }
@ -2904,24 +2905,25 @@ nsIContent* EditorBase::GetNextNodeInternal(const EditorRawDOMPoint& aPoint,
      return point.GetChild();
    }

-    nsIContent* leftMostContent =
-        GetLeftmostChild(point.GetChild(), aNoBlockCrossing);
-    if (!leftMostContent) {
+    nsIContent* firstLeafContent = HTMLEditUtils::GetFirstLeafChild(
+        *point.GetChild(), aNoBlockCrossing ? ChildBlockBoundary::TreatAsLeaf
+                                            : ChildBlockBoundary::Ignore);
+    if (!firstLeafContent) {
      return point.GetChild();
    }

-    if (!IsDescendantOfEditorRoot(leftMostContent)) {
+    if (!IsDescendantOfEditorRoot(firstLeafContent)) {
      return nullptr;
    }

    if ((!aFindEditableNode ||
-         EditorUtils::IsEditableContent(*leftMostContent, GetEditorType())) &&
-        (aFindAnyDataNode || EditorUtils::IsElementOrText(*leftMostContent))) {
-      return leftMostContent;
+         EditorUtils::IsEditableContent(*firstLeafContent, GetEditorType())) &&
+        (aFindAnyDataNode || EditorUtils::IsElementOrText(*firstLeafContent))) {
+      return firstLeafContent;
    }

    // restart the search from the non-editable node we just found
-    return GetNextNodeInternal(*leftMostContent, aFindEditableNode,
+    return GetNextNodeInternal(*firstLeafContent, aFindEditableNode,
                               aFindAnyDataNode, aNoBlockCrossing);
  }

@ -2955,17 +2957,14 @@ nsIContent* EditorBase::FindNextLeafNode(nsINode* aCurrentNode, bool aGoForward,
        // don't look inside prevsib, since it is a block
        return sibling;
      }
-      nsIContent* leaf =
+      ChildBlockBoundary childBlockBoundary =
+          bNoBlockCrossing ? ChildBlockBoundary::TreatAsLeaf
+                           : ChildBlockBoundary::Ignore;
+      nsIContent* leafContent =
          aGoForward
-              ? GetLeftmostChild(sibling, bNoBlockCrossing)
-              : HTMLEditUtils::GetLastLeafChild(
-                    *sibling, bNoBlockCrossing ? ChildBlockBoundary::TreatAsLeaf
-                                               : ChildBlockBoundary::Ignore);
-      if (!leaf) {
-        return sibling;
-      }
-
-      return leaf;
+              ? HTMLEditUtils::GetFirstLeafChild(*sibling, childBlockBoundary)
+              : HTMLEditUtils::GetLastLeafChild(*sibling, childBlockBoundary);
+      return leafContent ? leafContent : sibling;
    }

    nsINode* parent = cur->GetParentNode();
@ -3018,30 +3017,6 @@ nsIContent* EditorBase::FindNode(nsINode* aCurrentNode, bool aGoForward,
                  bNoBlockCrossing);
 }

-nsIContent* EditorBase::GetLeftmostChild(nsINode* aCurrentNode,
-                                         bool bNoBlockCrossing) const {
-  if (NS_WARN_IF(!aCurrentNode)) {
-    return nullptr;
-  }
-  nsIContent* content = aCurrentNode->GetFirstChild();
-  if (!content) {
-    return nullptr;
-  }
-  for (;;) {
-    if (bNoBlockCrossing && HTMLEditUtils::IsBlockElement(*content)) {
-      return content;
-    }
-    nsIContent* next = content->GetFirstChild();
-    if (!next) {
-      return content;
-    }
-    content = next;
-  }
-
-  MOZ_ASSERT_UNREACHABLE("What part of for(;;) do you not understand?");
-  return nullptr;
-}
-
 bool EditorBase::IsRoot(nsINode* inNode) const {
  if (NS_WARN_IF(!inNode)) {
    return false;
--- a/editor/libeditor/EditorBase.h
+++ b/editor/libeditor/EditorBase.h
@ -1695,13 +1695,6 @@ class EditorBase : public nsIEditor,
    return GetNextNodeInternal(aNode, true, true, true);
  }

-  /**
-   * Get the leftmost child of aCurrentNode;
-   * return nullptr if aCurrentNode has no children.
-   */
-  nsIContent* GetLeftmostChild(nsINode* aCurrentNode,
-                               bool bNoBlockCrossing = false) const;
-
  /**
   * Returns true if aNode is our root node.
   */
--- a/editor/libeditor/HTMLEditSubActionHandler.cpp
+++ b/editor/libeditor/HTMLEditSubActionHandler.cpp
@ -7859,8 +7859,9 @@ nsresult HTMLEditor::MaybeExtendSelectionToHardLineEdgesForBlockEditAction() {
    // of going "down" into a block and "up" out of a block.
    if (wsScannerAtStart.EndsByOtherBlockElement()) {
      // startpoint is just before the start of a block.
-      nsINode* child = GetLeftmostChild(
-          wsScannerAtStart.EndReasonOtherBlockElementPtr(), true);
+      nsINode* child = HTMLEditUtils::GetFirstLeafChild(
+          *wsScannerAtStart.EndReasonOtherBlockElementPtr(),
+          ChildBlockBoundary::TreatAsLeaf);
      if (child) {
        newStartPoint.Set(child);
      }
@ -9243,7 +9244,8 @@ nsresult HTMLEditor::SplitParagraph(

  // selection to beginning of right hand para;
  // look inside any containers that are up front.
-  nsCOMPtr<nsIContent> child = GetLeftmostChild(&aParentDivOrP, true);
+  nsCOMPtr<nsIContent> child = HTMLEditUtils::GetFirstLeafChild(
+      aParentDivOrP, ChildBlockBoundary::TreatAsLeaf);
  if (child && (child->IsText() || HTMLEditUtils::IsContainerNode(*child))) {
    nsresult rv = CollapseSelectionToStartOf(*child);
    if (NS_WARN_IF(rv == NS_ERROR_EDITOR_DESTROYED)) {
--- a/editor/libeditor/HTMLEditUtils.h
+++ b/editor/libeditor/HTMLEditUtils.h
@ -220,6 +220,26 @@ class HTMLEditUtils final {
    return nullptr;
  }

+  /**
+   * GetFirstLeafChild() returns leftmost leaf content in aNode.  It depends on
+   * aChildBlockBoundary whether this scans into a block child or treat
+   * block as a leaf.
+   */
+  static nsIContent* GetFirstLeafChild(nsINode& aNode,
+                                       ChildBlockBoundary aChildBlockBoundary) {
+    for (nsIContent* content = aNode.GetFirstChild(); content;
+         content = content->GetFirstChild()) {
+      if (aChildBlockBoundary == ChildBlockBoundary::TreatAsLeaf &&
+          HTMLEditUtils::IsBlockElement(*content)) {
+        return content;
+      }
+      if (!content->HasChildren()) {
+        return content;
+      }
+    }
+    return nullptr;
+  }
+
  /**
   * GetAncestorBlockElement() returns parent or nearest ancestor of aContent
   * which is a block element.  If aAncestorLimiter is not nullptr,
--- a/editor/libeditor/HTMLEditor.cpp
+++ b/editor/libeditor/HTMLEditor.cpp
@ -2745,7 +2745,8 @@ already_AddRefed<Element> HTMLEditor::GetSelectedElement(const nsAtom* aTagName,
      if (nextSibling->IsHTMLElement(nsGkAtoms::br)) {
        return nullptr;
      }
-      nsIContent* firstEditableLeaf = GetLeftmostChild(nextSibling);
+      nsIContent* firstEditableLeaf = HTMLEditUtils::GetFirstLeafChild(
+          *nextSibling, ChildBlockBoundary::Ignore);
      if (firstEditableLeaf &&
          firstEditableLeaf->IsHTMLElement(nsGkAtoms::br)) {
        return nullptr;
@ -4960,7 +4961,8 @@ nsIContent* HTMLEditor::GetLastEditableChild(nsINode& aNode) const {
 }

 nsIContent* HTMLEditor::GetFirstEditableLeaf(nsINode& aNode) const {
-  nsIContent* child = GetLeftmostChild(&aNode);
+  nsIContent* child =
+      HTMLEditUtils::GetFirstLeafChild(aNode, ChildBlockBoundary::Ignore);
  while (child && (!EditorUtils::IsEditableContent(*child, EditorType::HTML) ||
                   child->HasChildren())) {
    child = GetNextEditableHTMLNode(*child);
--- a/editor/libeditor/HTMLStyleEditor.cpp
+++ b/editor/libeditor/HTMLStyleEditor.cpp
@ -46,6 +46,8 @@ namespace mozilla {

 using namespace dom;

+using ChildBlockBoundary = HTMLEditUtils::ChildBlockBoundary;
+
 nsresult HTMLEditor::SetInlinePropertyAsAction(nsAtom& aProperty,
                                               nsAtom* aAttribute,
                                               const nsAString& aValue,
@ -880,10 +882,10 @@ EditResult HTMLEditor::ClearStyleAt(const EditorDOMPoint& aPoint,
  // the next node.  The first example should become
  // `<p><b><i>a</i></b><b><i></i></b><b><i>bc</i></b></p>`.
  //                    ^^^^^^^^^^^^^^
-  nsIContent* leftmostChildOfNextNode =
-      GetLeftmostChild(splitResult.GetNextNode());
-  EditorDOMPoint atStartOfNextNode(leftmostChildOfNextNode
-                                       ? leftmostChildOfNextNode
+  nsIContent* firstLeafChildOfNextNode = HTMLEditUtils::GetFirstLeafChild(
+      *splitResult.GetNextNode(), ChildBlockBoundary::Ignore);
+  EditorDOMPoint atStartOfNextNode(firstLeafChildOfNextNode
+                                       ? firstLeafChildOfNextNode
                                       : splitResult.GetNextNode(),
                                   0);
  RefPtr<HTMLBRElement> brElement;
@ -938,10 +940,12 @@ EditResult HTMLEditor::ClearStyleAt(const EditorDOMPoint& aPoint,
  // Now, we want to put `<br>` element into the empty split node if
  // it was in next node of the first split.
  // E.g., `<p><b><i>a</i></b><b><i><br></i></b><b><i>bc</i></b></p>`
-  nsIContent* leftmostChild =
-      GetLeftmostChild(splitResultAtStartOfNextNode.GetPreviousNode());
+  nsIContent* firstLeafChildOfPreviousNode = HTMLEditUtils::GetFirstLeafChild(
+      *splitResultAtStartOfNextNode.GetPreviousNode(),
+      ChildBlockBoundary::Ignore);
  EditorDOMPoint pointToPutCaret(
-      leftmostChild ? leftmostChild
+      firstLeafChildOfPreviousNode
+          ? firstLeafChildOfPreviousNode
          : splitResultAtStartOfNextNode.GetPreviousNode(),
      0);
  // If the right node starts with a `<br>`, suck it out of right node and into
--- a/editor/libeditor/TextEditor.cpp
+++ b/editor/libeditor/TextEditor.cpp
@ -8,6 +8,7 @@
 #include <algorithm>

 #include "EditAggregateTransaction.h"
+#include "HTMLEditUtils.h"
 #include "InternetCiter.h"
 #include "PlaceholderTransaction.h"
 #include "gfxFontUtils.h"
@ -69,6 +70,8 @@ namespace mozilla {

 using namespace dom;

+using ChildBlockBoundary = HTMLEditUtils::ChildBlockBoundary;
+
 TextEditor::TextEditor()
    : mMaxTextLength(-1),
      mUnmaskedStart(UINT32_MAX),
@ -1000,11 +1003,12 @@ nsresult TextEditor::UndoAsAction(uint32_t aCount, nsIPrincipal* aPrincipal) {
      // at redo, or doing it everywhere else that might care.  Since undo
      // and redo are relatively rare, it makes sense to take the (small)
      // performance hit here.
-      nsIContent* leftMostChild = GetLeftmostChild(mRootElement);
-      if (leftMostChild &&
-          EditorUtils::IsPaddingBRElementForEmptyEditor(*leftMostChild)) {
+      nsIContent* firstLeafChild = HTMLEditUtils::GetFirstLeafChild(
+          *mRootElement, ChildBlockBoundary::Ignore);
+      if (firstLeafChild &&
+          EditorUtils::IsPaddingBRElementForEmptyEditor(*firstLeafChild)) {
        mPaddingBRElementForEmptyEditor =
-            static_cast<HTMLBRElement*>(leftMostChild);
+            static_cast<HTMLBRElement*>(firstLeafChild);
      } else {
        mPaddingBRElementForEmptyEditor = nullptr;
      }
--- a/editor/libeditor/WSRunObject.cpp
+++ b/editor/libeditor/WSRunObject.cpp
@ -1238,8 +1238,8 @@ nsIContent* WSRunScanner::GetNextWSNodeInner(nsINode* aStartNode,
  }
  if (HTMLEditUtils::IsContainerNode(*nextContent)) {
    // Else if it's a container, get deep leftmost child
-    nsCOMPtr<nsIContent> child = mHTMLEditor->GetLeftmostChild(nextContent);
-    if (child) {
+    if (nsIContent* child = HTMLEditUtils::GetFirstLeafChild(
+            *nextContent, ChildBlockBoundary::Ignore)) {
      return child;
    }
  }
@ -1283,8 +1283,8 @@ nsIContent* WSRunScanner::GetNextWSNode(const EditorDOMPoint& aPoint,
  }
  if (HTMLEditUtils::IsContainerNode(*nextContent)) {
    // else if it's a container, get deep leftmost child
-    nsCOMPtr<nsIContent> child = mHTMLEditor->GetLeftmostChild(nextContent);
-    if (child) {
+    if (nsIContent* child = HTMLEditUtils::GetFirstLeafChild(
+            *nextContent, ChildBlockBoundary::Ignore)) {
      return child;
    }
  }