Commit ed99e91e authored by Masayuki Nakano's avatar Masayuki Nakano
Browse files

Bug 1898408 - Make our editor disconnect `<br>` element temporarily when its... 

Bug 1898408 - Make our editor disconnect `<br>` element temporarily when its type is changed from or to padding one r=m_kato

Currently, the `<br>` element type -- whether normal `<br>` element or padding
`<br>` element for empty editor or last line -- is managed by the flags of
`nsINode`.  Therefore, changing the flag does not cause mutation, so
`IMEContentObserver` cannot observe the type changes.  However,
`ContentEventHandler` treats the padding `<br>` elements as invisible.
Therefore, when a `<br>` element becomes a padding one, `IMEContentObserver`
needs to notify IME of atext removed notification, and also when a `<br>`
element becomes a normal one (i.e., visible), `IMEContentObserver` needs to
notify IME of a text added notification.

Therefore, this patch makes `EditorBase` disconnect the `<br>` element
temporarily to make `IMEContentObserver` observable the type change.

Depends on D211698

Differential Revision: https://phabricator.services.mozilla.com/D211699
parent cb97c623

editor/libeditor/EditorBase.cpp

+80 −6
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include "DeleteTextTransaction.h"

#include "EditAction.h"      // for EditSubAction

#include "EditorDOMPoint.h"  // for EditorDOMPoint

#include "EditorForwards.h"

#include "EditorUtils.h"          // for various helper classes.

#include "EditTransactionBase.h"  // for EditTransactionBase

#include "EditorEventListener.h"  // for EditorEventListener
@@ -35,6 +36,7 @@ 
#include "gfxFontUtils.h"  // for gfxFontUtils

#include "mozilla/Assertions.h"

#include "mozilla/AsyncEventDispatcher.h"

#include "mozilla/EditorDOMPoint.h"

#include "mozilla/intl/BidiEmbeddingLevel.h"

#include "mozilla/BasePrincipal.h"            // for BasePrincipal

#include "mozilla/CheckedInt.h"               // for CheckedInt
@@ -2414,11 +2416,17 @@ EditorBase::InsertPaddingBRElementForEmptyLastLineWithTransaction( 
    pointToInsert = maybePointToInsert.unwrap();

  }



  RefPtr<Element> newBRElement = CreateHTMLContent(nsGkAtoms::br);

  RefPtr<HTMLBRElement> newBRElement =

      HTMLBRElement::FromNodeOrNull(RefPtr{CreateHTMLContent(nsGkAtoms::br)});

  if (NS_WARN_IF(!newBRElement)) {

    return Err(NS_ERROR_FAILURE);

  }

  newBRElement->SetFlags(NS_PADDING_FOR_EMPTY_LAST_LINE);

  nsresult rv = UpdateBRElementType(*newBRElement,

                                    BRElementType::PaddingForEmptyLastLine);

  if (NS_FAILED(rv)) {

    NS_WARNING("EditorBase::UpdateBRElementType() failed");

    return Err(rv);

  }



  Result<CreateElementResult, nsresult> insertBRElementResult =

      InsertNodeWithTransaction<Element>(*newBRElement, pointToInsert);
@@ -2427,6 +2435,68 @@ EditorBase::InsertPaddingBRElementForEmptyLastLineWithTransaction( 
  return insertBRElementResult;

}



nsresult EditorBase::UpdateBRElementType(HTMLBRElement& aBRElement,

                                         BRElementType aNewType) {

  const bool brElementIsHidden = aBRElement.IsPaddingForEmptyEditor() ||

                                 aBRElement.IsPaddingForEmptyLastLine();

  const bool brElementWillBeHidden = aNewType != BRElementType::Normal;

  const auto SetBRElementFlags = [&]() {

    switch (aNewType) {

      case BRElementType::Normal:

        if (brElementIsHidden) {

          aBRElement.UnsetFlags(NS_PADDING_FOR_EMPTY_EDITOR |

                                NS_PADDING_FOR_EMPTY_LAST_LINE);

        }

        break;

      case BRElementType::PaddingForEmptyEditor:

        if (brElementIsHidden) {

          aBRElement.UnsetFlags(NS_PADDING_FOR_EMPTY_LAST_LINE);

        }

        aBRElement.SetFlags(NS_PADDING_FOR_EMPTY_EDITOR);

        break;

      case BRElementType::PaddingForEmptyLastLine:

        if (brElementIsHidden) {

          aBRElement.UnsetFlags(NS_PADDING_FOR_EMPTY_EDITOR);

        }

        aBRElement.SetFlags(NS_PADDING_FOR_EMPTY_LAST_LINE);

        break;

    }

  };

  // If the <br> element is in the composed doc, it must be observed by

  // IMEContentObserver.  However, IMEContentObserver cannot observe the state

  // change, but changing the <br> type may make the <br> element visible or

  // invisible for ContentEventHandler.  Therefore, IMEContentObserver needs to

  // notify IME of the state change as a text change notification of adding or

  // removing a line break.  Therefore, we need to reconnect the <br> element

  // temporarily for making IMEContentObserver observable this change.

  if (!aBRElement.IsInComposedDoc() ||

      brElementIsHidden == brElementWillBeHidden) {

    SetBRElementFlags();

    return NS_OK;

  }

  EditorDOMPoint pointToInsert(&aBRElement);

  {

    AutoEditorDOMPointChildInvalidator lockOffset(pointToInsert);

    nsresult rv = DeleteNodeWithTransaction(aBRElement);

    if (NS_FAILED(rv)) {

      NS_WARNING("EditorBase::DeleteNodeWithTransaction() failed");

      return rv;

    }

  }

  if (NS_WARN_IF(!pointToInsert.IsSetAndValid())) {

    return NS_ERROR_EDITOR_UNEXPECTED_DOM_TREE;

  }

  SetBRElementFlags();

  Result<CreateElementResult, nsresult> result =

      InsertNodeWithTransaction<Element>(aBRElement, pointToInsert);

  if (MOZ_UNLIKELY(result.isErr())) {

    NS_WARNING("EditorBase::InsertNodeWithTransaction() failed");

    return result.unwrapErr();

  }

  result.inspect().IgnoreCaretPointSuggestion();

  return NS_OK;

}



NS_IMETHODIMP EditorBase::DeleteNode(nsINode* aNode, bool aPreserveSelection,

                                     uint8_t aOptionalArgCount) {

  MOZ_ASSERT_UNREACHABLE("Do not use this API with TextEditor");
@@ -3654,8 +3724,12 @@ nsresult EditorBase::EnsurePaddingBRElementInMultilineEditor() { 
  }



  // Morph it back to a padding <br> element for empty last line.

  brElement->UnsetFlags(NS_PADDING_FOR_EMPTY_EDITOR);

  brElement->SetFlags(NS_PADDING_FOR_EMPTY_LAST_LINE);

  nsresult rv =

      UpdateBRElementType(*brElement, BRElementType::PaddingForEmptyLastLine);

  if (NS_FAILED(rv)) {

    NS_WARNING("EditorBase::UpdateBRElementType() failed");

    return rv;

  }



  return NS_OK;

}

editor/libeditor/EditorBase.h

+13 −0
Original line number Diff line number Diff line
@@ -1754,6 +1754,19 @@ class EditorBase : public nsIEditor, 
  InsertPaddingBRElementForEmptyLastLineWithTransaction(

      const EditorDOMPoint& aPointToInsert);



  enum class BRElementType {

    Normal,

    PaddingForEmptyEditor,

    PaddingForEmptyLastLine

  };

  /**

   * Updates the type of aBRElement.  If it will be hidden or shown from

   * IMEContentObserver and ContentEventHandler points of view, this temporarily

   * removes the node and reconnect to the same position.

   */

  [[nodiscard]] MOZ_CAN_RUN_SCRIPT nsresult

  UpdateBRElementType(dom::HTMLBRElement& aBRElement, BRElementType aNewType);



  /**

   * CloneAttributesWithTransaction() clones all attributes from

   * aSourceElement to aDestElement after removing all attributes in

editor/libeditor/HTMLEditSubActionHandler.cpp

+16 −6
Original line number Diff line number Diff line
@@ -974,7 +974,8 @@ nsresult HTMLEditor::MaybeCreatePaddingBRElementForEmptyEditor() { 
      "HTMLEditor::OnStartToHandleTopLevelEditSubAction() failed, but ignored");









  // Create a br.









  RefPtr<Element> newBRElement = CreateHTMLContent(nsGkAtoms::br);









  RefPtr<HTMLBRElement> newBRElement =









      HTMLBRElement::FromNodeOrNull(RefPtr{CreateHTMLContent(nsGkAtoms::br)});









  if (NS_WARN_IF(Destroyed())) {









    return NS_ERROR_EDITOR_DESTROYED;









  }








@@ -982,11 +983,15 @@ nsresult HTMLEditor::MaybeCreatePaddingBRElementForEmptyEditor() {







    return NS_ERROR_FAILURE;









  }

















  mPaddingBRElementForEmptyEditor =









      static_cast<HTMLBRElement*>(newBRElement.get());









  mPaddingBRElementForEmptyEditor = newBRElement;

















  // Give it a special attribute.









  newBRElement->SetFlags(NS_PADDING_FOR_EMPTY_EDITOR);









  nsresult rv =









      UpdateBRElementType(*newBRElement, BRElementType::PaddingForEmptyEditor);









  if (NS_FAILED(rv)) {









    NS_WARNING("EditorBase::UpdateBRElementType() failed");









    return rv;









  }

















  // Put the node in the document.









  Result<CreateElementResult, nsresult> insertBRElementResult =








@@ -999,7 +1004,7 @@ nsresult HTMLEditor::MaybeCreatePaddingBRElementForEmptyEditor() {















  // Set selection.









  insertBRElementResult.inspect().IgnoreCaretPointSuggestion();









  nsresult rv = CollapseSelectionToStartOf(*bodyOrDocumentElement);









  rv = CollapseSelectionToStartOf(*bodyOrDocumentElement);









  if (MOZ_UNLIKELY(rv == NS_ERROR_EDITOR_DESTROYED)) {









    NS_WARNING(









        "EditorBase::CollapseSelectionToStartOf() caused destroying the "








@@ -8698,7 +8703,12 @@ Result<SplitNodeResult, nsresult> HTMLEditor::SplitParagraphWithTransaction(







      // <br>.









      if (brElement &&









          brElement->GetParentNode() == deepestInlineContainerElement) {









        brElement->SetFlags(NS_PADDING_FOR_EMPTY_LAST_LINE);









        nsresult rv = UpdateBRElementType(









            *brElement, BRElementType::PaddingForEmptyLastLine);









        if (NS_FAILED(rv)) {









          NS_WARNING("EditorBase::UpdateBRElementType() failed");









          return Err(rv);









        }









        return SplitNodeResult(std::move(unwrappedSplitDivOrPResult),









                               EditorDOMPoint(brElement));









      }