chromium/src/third_party/blink/renderer/core/editing/serializers/html_interchange.cc

/*
 * Copyright (C) 2004, 2008 Apple Inc.  All rights reserved.
 *
 * 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 "third_party/blink/renderer/core/editing/serializers/html_interchange.h"

#include "third_party/blink/renderer/core/dom/text.h"
#include "third_party/blink/renderer/core/editing/editing_utilities.h"
#include "third_party/blink/renderer/core/layout/layout_object.h"
#include "third_party/blink/renderer/core/layout/layout_text.h"
#include "third_party/blink/renderer/platform/wtf/text/character_names.h"
#include "third_party/blink/renderer/platform/wtf/text/string_builder.h"

namespace blink {

String ConvertHTMLTextToInterchangeFormat(const String& in, const Text& node) {
  // Assume all the text comes from node.
  if (node.GetLayoutObject() &&
      node.GetLayoutObject()->Style()->PreserveNewline())
    return in;

  const char kConvertedSpaceString[] = "<span>\xA0</span>";
  static_assert((static_cast<unsigned char>('\xA0') == kNoBreakSpaceCharacter),
                "\\xA0 should be non-breaking space");

  StringBuilder s;

  unsigned i = 0;
  unsigned consumed = 0;
  while (i < in.length()) {
    consumed = 1;
    if (IsCollapsibleWhitespace(in[i])) {
      // count number of adjoining spaces
      unsigned j = i + 1;
      while (j < in.length() && IsCollapsibleWhitespace(in[j]))
        j++;
      unsigned count = j - i;
      consumed = count;
      while (count) {
        unsigned add = count % 3;
        switch (add) {
          case 0:
            s.Append(kConvertedSpaceString);
            s.Append(' ');
            s.Append(kConvertedSpaceString);
            add = 3;
            break;
          case 1:
            if (i == 0 || i + 1 == in.length())  // at start or end of string
              s.Append(kConvertedSpaceString);
            else
              s.Append(' ');
            break;
          case 2:
            if (i == 0) {
              // at start of string
              s.Append(kConvertedSpaceString);
              s.Append(' ');
            } else if (i + 2 == in.length()) {
              // at end of string
              s.Append(kConvertedSpaceString);
              s.Append(kConvertedSpaceString);
            } else {
              s.Append(kConvertedSpaceString);
              s.Append(' ');
            }
            break;
        }
        count -= add;
      }
    } else {
      s.Append(in[i]);
    }
    i += consumed;
  }

  return s.ToString();
}

}  // namespace blink