gecko-dev/editor/libeditor/DeleteRangeTransaction.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 "DeleteRangeTransaction.h"

#include "DeleteNodeTransaction.h"
#include "DeleteTextTransaction.h"
#include "mozilla/Assertions.h"
#include "mozilla/ContentIterator.h"
#include "mozilla/dom/Selection.h"
#include "mozilla/EditorBase.h"
#include "mozilla/mozalloc.h"
#include "mozilla/RangeBoundary.h"
#include "nsCOMPtr.h"
#include "nsDebug.h"
#include "nsError.h"
#include "nsIContent.h"
#include "nsINode.h"
#include "nsAString.h"

namespace mozilla {

using namespace dom;

DeleteRangeTransaction::DeleteRangeTransaction(EditorBase& aEditorBase,
                                               nsRange& aRangeToDelete)
    : mEditorBase(&aEditorBase), mRangeToDelete(aRangeToDelete.CloneRange()) {}

NS_IMPL_CYCLE_COLLECTION_INHERITED(DeleteRangeTransaction,
                                   EditAggregateTransaction, mEditorBase,
                                   mRangeToDelete)

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DeleteRangeTransaction)
NS_INTERFACE_MAP_END_INHERITING(EditAggregateTransaction)

NS_IMETHODIMP
DeleteRangeTransaction::DoTransaction() {
  if (NS_WARN_IF(!mEditorBase) || NS_WARN_IF(!mRangeToDelete)) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  // Swap mRangeToDelete out into a stack variable, so we make sure to null it
  // out on return from this function.  Once this function returns, we no longer
  // need mRangeToDelete, and keeping it alive in the long term slows down all
  // DOM mutations because it's observing them.
  RefPtr<nsRange> rangeToDelete;
  rangeToDelete.swap(mRangeToDelete);

  // build the child transactions
  const RangeBoundary& startRef = rangeToDelete->StartRef();
  const RangeBoundary& endRef = rangeToDelete->EndRef();
  MOZ_ASSERT(startRef.IsSetAndValid());
  MOZ_ASSERT(endRef.IsSetAndValid());

  if (startRef.Container() == endRef.Container()) {
    // the selection begins and ends in the same node
    nsresult rv = CreateTxnsToDeleteBetween(startRef.AsRaw(), endRef.AsRaw());
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }
  } else {
    // the selection ends in a different node from where it started.  delete
    // the relevant content in the start node
    nsresult rv = CreateTxnsToDeleteContent(startRef.AsRaw(), nsIEditor::eNext);
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }
    // delete the intervening nodes
    rv = CreateTxnsToDeleteNodesBetween(rangeToDelete);
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }
    // delete the relevant content in the end node
    rv = CreateTxnsToDeleteContent(endRef.AsRaw(), nsIEditor::ePrevious);
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }
  }

  // if we've successfully built this aggregate transaction, then do it.
  nsresult rv = EditAggregateTransaction::DoTransaction();
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  if (!mEditorBase->AllowsTransactionsToChangeSelection()) {
    return NS_OK;
  }

  RefPtr<Selection> selection = mEditorBase->GetSelection();
  if (NS_WARN_IF(!selection)) {
    return NS_ERROR_NULL_POINTER;
  }
  rv = selection->Collapse(startRef.AsRaw());
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  return NS_OK;
}

NS_IMETHODIMP
DeleteRangeTransaction::UndoTransaction() {
  return EditAggregateTransaction::UndoTransaction();
}

NS_IMETHODIMP
DeleteRangeTransaction::RedoTransaction() {
  return EditAggregateTransaction::RedoTransaction();
}

nsresult DeleteRangeTransaction::CreateTxnsToDeleteBetween(
    const RawRangeBoundary& aStart, const RawRangeBoundary& aEnd) {
  if (NS_WARN_IF(!aStart.IsSetAndValid()) ||
      NS_WARN_IF(!aEnd.IsSetAndValid()) ||
      NS_WARN_IF(aStart.Container() != aEnd.Container())) {
    return NS_ERROR_INVALID_ARG;
  }

  if (NS_WARN_IF(!mEditorBase)) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  // see what kind of node we have
  if (RefPtr<Text> textNode = Text::FromNode(aStart.Container())) {
    // if the node is a chardata node, then delete chardata content
    int32_t numToDel;
    if (aStart == aEnd) {
      numToDel = 1;
    } else {
      numToDel = aEnd.Offset() - aStart.Offset();
      MOZ_DIAGNOSTIC_ASSERT(numToDel > 0);
    }

    RefPtr<DeleteTextTransaction> deleteTextTransaction =
        DeleteTextTransaction::MaybeCreate(*mEditorBase, *textNode,
                                           aStart.Offset(), numToDel);
    // If the text node isn't editable, it should be never undone/redone.
    // So, the transaction shouldn't be recorded.
    if (NS_WARN_IF(!deleteTextTransaction)) {
      return NS_ERROR_FAILURE;
    }
    AppendChild(deleteTextTransaction);
    return NS_OK;
  }

  // Even if we detect invalid range, we should ignore it for removing
  // specified range's nodes as far as possible.
  for (nsIContent* child = aStart.GetChildAtOffset();
       child && child != aEnd.GetChildAtOffset();
       child = child->GetNextSibling()) {
    RefPtr<DeleteNodeTransaction> deleteNodeTransaction =
        DeleteNodeTransaction::MaybeCreate(*mEditorBase, *child);
    // XXX This is odd handling.  Even if some children are not editable,
    //     editor should append transactions because they could be editable
    //     at undoing/redoing.  Additionally, if the transaction needs to
    //     delete/restore all nodes, it should at undoing/redoing.
    if (deleteNodeTransaction) {
      AppendChild(deleteNodeTransaction);
    }
  }

  return NS_OK;
}

nsresult DeleteRangeTransaction::CreateTxnsToDeleteContent(
    const RawRangeBoundary& aPoint, nsIEditor::EDirection aAction) {
  if (NS_WARN_IF(!aPoint.IsSetAndValid())) {
    return NS_ERROR_INVALID_ARG;
  }

  if (NS_WARN_IF(!mEditorBase)) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  RefPtr<Text> textNode = Text::FromNode(aPoint.Container());
  if (!textNode) {
    return NS_OK;
  }

  // If the node is a chardata node, then delete chardata content
  uint32_t startOffset, numToDelete;
  if (nsIEditor::eNext == aAction) {
    startOffset = aPoint.Offset();
    numToDelete = aPoint.Container()->Length() - aPoint.Offset();
  } else {
    startOffset = 0;
    numToDelete = aPoint.Offset();
  }

  if (!numToDelete) {
    return NS_OK;
  }

  RefPtr<DeleteTextTransaction> deleteTextTransaction =
      DeleteTextTransaction::MaybeCreate(*mEditorBase, *textNode, startOffset,
                                         numToDelete);
  // If the text node isn't editable, it should be never undone/redone.
  // So, the transaction shouldn't be recorded.
  if (NS_WARN_IF(!deleteTextTransaction)) {
    return NS_ERROR_FAILURE;
  }
  AppendChild(deleteTextTransaction);

  return NS_OK;
}

nsresult DeleteRangeTransaction::CreateTxnsToDeleteNodesBetween(
    nsRange* aRangeToDelete) {
  if (NS_WARN_IF(!mEditorBase)) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  ContentSubtreeIterator subtreeIter;
  nsresult rv = subtreeIter.Init(aRangeToDelete);
  NS_ENSURE_SUCCESS(rv, rv);

  while (!subtreeIter.IsDone()) {
    nsCOMPtr<nsINode> node = subtreeIter.GetCurrentNode();
    if (NS_WARN_IF(!node)) {
      return NS_ERROR_NULL_POINTER;
    }

    RefPtr<DeleteNodeTransaction> deleteNodeTransaction =
        DeleteNodeTransaction::MaybeCreate(*mEditorBase, *node);
    // XXX This is odd handling.  Even if some nodes in the range are not
    //     editable, editor should append transactions because they could
    //     at undoing/redoing.  Additionally, if the transaction needs to
    //     delete/restore all nodes, it should at undoing/redoing.
    if (NS_WARN_IF(!deleteNodeTransaction)) {
      return NS_ERROR_FAILURE;
    }
    AppendChild(deleteNodeTransaction);

    subtreeIter.Next();
  }
  return NS_OK;
}

}  // namespace mozilla