third_party/WebKit/Source/core/editing/PlainTextRange.cpp

/*
 * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All
 * rights reserved.
 * Copyright (C) 2005 Alexey Proskuryakov.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "core/editing/PlainTextRange.h"

#include "core/dom/ContainerNode.h"
#include "core/dom/Document.h"
#include "core/dom/Range.h"
#include "core/editing/EphemeralRange.h"
#include "core/editing/VisiblePosition.h"
#include "core/editing/VisibleUnits.h"
#include "core/editing/iterators/TextIterator.h"

namespace blink {

PlainTextRange::PlainTextRange() : m_start(kNotFound), m_end(kNotFound) {}

PlainTextRange::PlainTextRange(int location)
    : m_start(location), m_end(location) {
  DCHECK_GE(location, 0);
}

PlainTextRange::PlainTextRange(int start, int end)
    : m_start(start), m_end(end) {
  DCHECK_GE(start, 0);
  DCHECK_GE(end, 0);
  DCHECK_LE(start, end);
}

EphemeralRange PlainTextRange::createRange(const ContainerNode& scope) const {
  return createRangeFor(scope, ForGeneric);
}

EphemeralRange PlainTextRange::createRangeForSelection(
    const ContainerNode& scope) const {
  return createRangeFor(scope, ForSelection);
}

EphemeralRange PlainTextRange::createRangeFor(const ContainerNode& scope,
                                              GetRangeFor getRangeFor) const {
  DCHECK(isNotNull());

  size_t docTextPosition = 0;
  bool startRangeFound = false;

  Position textRunStartPosition;
  Position textRunEndPosition;

  TextIteratorBehaviorFlags behaviorFlags =
      TextIteratorEmitsObjectReplacementCharacter;
  if (getRangeFor == ForSelection)
    behaviorFlags |= TextIteratorEmitsCharactersBetweenAllVisiblePositions;
  auto range = EphemeralRange::rangeOfContents(scope);

  TextIterator it(range.startPosition(), range.endPosition(), behaviorFlags);

  // FIXME: the atEnd() check shouldn't be necessary, workaround for
  // <http://bugs.webkit.org/show_bug.cgi?id=6289>.
  if (!start() && !length() && it.atEnd())
    return EphemeralRange(Position(it.currentContainer(), 0));

  Position resultStart = Position(&scope.document(), 0);
  Position resultEnd = resultStart;

  for (; !it.atEnd(); it.advance()) {
    int len = it.length();

    textRunStartPosition = it.startPositionInCurrentContainer();
    textRunEndPosition = it.endPositionInCurrentContainer();

    bool foundStart =
        start() >= docTextPosition && start() <= docTextPosition + len;
    bool foundEnd = end() >= docTextPosition && end() <= docTextPosition + len;

    // Fix textRunRange->endPosition(), but only if foundStart || foundEnd,
    // because it is only in those cases that textRunRange is used.
    if (foundEnd) {
      // FIXME: This is a workaround for the fact that the end of a run
      // is often at the wrong position for emitted '\n's or if the
      // layoutObject of the current node is a replaced element.
      if (len == 1 &&
          (it.characterAt(0) == '\n' || it.isInsideAtomicInlineElement())) {
        it.advance();
        if (!it.atEnd()) {
          textRunEndPosition = it.startPositionInCurrentContainer();
        } else {
          Position runEnd =
              nextPositionOf(createVisiblePosition(textRunStartPosition))
                  .deepEquivalent();
          if (runEnd.isNotNull())
            textRunEndPosition = runEnd;
        }
      }
    }

    if (foundStart) {
      startRangeFound = true;
      if (textRunStartPosition.computeContainerNode()->isTextNode()) {
        int offset = start() - docTextPosition;
        resultStart =
            Position(textRunStartPosition.computeContainerNode(),
                     offset + textRunStartPosition.offsetInContainerNode());
      } else {
        if (start() == docTextPosition)
          resultStart = textRunStartPosition;
        else
          resultStart = textRunEndPosition;
      }
    }

    if (foundEnd) {
      if (textRunStartPosition.computeContainerNode()->isTextNode()) {
        int offset = end() - docTextPosition;
        resultEnd =
            Position(textRunStartPosition.computeContainerNode(),
                     offset + textRunStartPosition.offsetInContainerNode());
      } else {
        if (end() == docTextPosition)
          resultEnd = textRunStartPosition;
        else
          resultEnd = textRunEndPosition;
      }
      docTextPosition += len;
      break;
    }
    docTextPosition += len;
  }

  if (!startRangeFound)
    return EphemeralRange();

  if (length() && end() > docTextPosition) {  // end() is out of bounds
    resultEnd = textRunEndPosition;
  }

  return EphemeralRange(resultStart.toOffsetInAnchor(),
                        resultEnd.toOffsetInAnchor());
}

PlainTextRange PlainTextRange::create(const ContainerNode& scope,
                                      const EphemeralRange& range) {
  if (range.isNull())
    return PlainTextRange();

  // The critical assumption is that this only gets called with ranges that
  // concentrate on a given area containing the selection root. This is done
  // because of text fields and textareas. The DOM for those is not
  // directly in the document DOM, so ensure that the range does not cross a
  // boundary of one of those.
  Node* startContainer = range.startPosition().computeContainerNode();
  if (startContainer != &scope && !startContainer->isDescendantOf(&scope))
    return PlainTextRange();
  Node* endContainer = range.endPosition().computeContainerNode();
  if (endContainer != scope && !endContainer->isDescendantOf(&scope))
    return PlainTextRange();

  DocumentLifecycle::DisallowTransitionScope disallowTransition(
      scope.document().lifecycle());

  size_t start = TextIterator::rangeLength(
      Position(&const_cast<ContainerNode&>(scope), 0), range.startPosition());
  size_t end = TextIterator::rangeLength(
      Position(&const_cast<ContainerNode&>(scope), 0), range.endPosition());

  return PlainTextRange(start, end);
}

PlainTextRange PlainTextRange::create(const ContainerNode& scope,
                                      const Range& range) {
  return create(scope, EphemeralRange(&range));
}

}  // namespace blink