gecko-dev/editor/libeditor/TextEditRulesBidi.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "mozilla/TextEditRules.h"

#include "mozilla/TextEditor.h"
#include "mozilla/dom/Selection.h"
#include "nsCOMPtr.h"
#include "nsDebug.h"
#include "nsError.h"
#include "nsFrameSelection.h"
#include "nsIContent.h"
#include "nsIEditor.h"
#include "nsISupportsImpl.h"
#include "nsPresContext.h"
#include "nscore.h"

namespace mozilla {

using namespace dom;

// Test for distance between caret and text that will be deleted
nsresult TextEditRules::CheckBidiLevelForDeletion(
    const EditorRawDOMPoint& aSelectionPoint, nsIEditor::EDirection aAction,
    bool* aCancel) {
  MOZ_ASSERT(IsEditorDataAvailable());

  if (NS_WARN_IF(!aCancel)) {
    return NS_ERROR_INVALID_ARG;
  }

  *aCancel = false;

  RefPtr<nsPresContext> presContext = TextEditorRef().GetPresContext();
  if (NS_WARN_IF(!presContext)) {
    return NS_ERROR_FAILURE;
  }

  if (!presContext->BidiEnabled()) {
    return NS_OK;
  }

  if (!aSelectionPoint.GetContainerAsContent()) {
    return NS_ERROR_FAILURE;
  }

  RefPtr<nsFrameSelection> frameSelection =
      SelectionRefPtr()->GetFrameSelection();
  if (NS_WARN_IF(!frameSelection)) {
    return NS_ERROR_FAILURE;
  }

  nsPrevNextBidiLevels levels = frameSelection->GetPrevNextBidiLevels(
      aSelectionPoint.GetContainerAsContent(), aSelectionPoint.Offset(), true);

  nsBidiLevel levelBefore = levels.mLevelBefore;
  nsBidiLevel levelAfter = levels.mLevelAfter;

  nsBidiLevel currentCaretLevel = frameSelection->GetCaretBidiLevel();

  nsBidiLevel levelOfDeletion;
  levelOfDeletion =
      (nsIEditor::eNext == aAction || nsIEditor::eNextWord == aAction)
          ? levelAfter
          : levelBefore;

  if (currentCaretLevel == levelOfDeletion) {
    return NS_OK;  // perform the deletion
  }

  if (!mDeleteBidiImmediately && levelBefore != levelAfter) {
    *aCancel = true;
  }

  // Set the bidi level of the caret to that of the
  // character that will be (or would have been) deleted
  frameSelection->SetCaretBidiLevel(levelOfDeletion);
  return NS_OK;
}

void TextEditRules::UndefineCaretBidiLevel() {
  MOZ_ASSERT(IsEditorDataAvailable());

  /**
   * After inserting text the caret Bidi level must be set to the level of the
   * inserted text.This is difficult, because we cannot know what the level is
   * until after the Bidi algorithm is applied to the whole paragraph.
   *
   * So we set the caret Bidi level to UNDEFINED here, and the caret code will
   * set it correctly later
   */
  RefPtr<nsFrameSelection> frameSelection =
      SelectionRefPtr()->GetFrameSelection();
  if (frameSelection) {
    frameSelection->UndefineCaretBidiLevel();
  }
}

}  // namespace mozilla