pjs/editor/base/nsWrapUtils.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * The contents of this file are subject to the Netscape Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/NPL/
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is Netscape
 * Communications Corporation.  Portions created by Netscape are
 * Copyright (C) 1998 Netscape Communications Corporation. All
 * Rights Reserved.
 *
 * Contributor(s): 
 */

#include "nsWrapUtils.h"

#include "nsCOMPtr.h"

// Line breaker stuff
#include "nsIServiceManager.h"
#include "nsILineBreakerFactory.h"
#include "nsLWBrkCIID.h"

static NS_DEFINE_CID(kLWBrkCID, NS_LWBRK_CID);

/*
 * Rewrap the given section of string, putting the result in aOutString.
 */
nsresult
nsWrapUtils::Rewrap(const nsString& aInString,
                    PRUint32 aWrapCol, PRUint32 aFirstLineOffset,
                    PRBool aRespectNewlines,
                    nsString aLineStartStr,
                    nsString& aOutString)
{
  PRInt32 i;

  nsCOMPtr<nsILineBreaker> lineBreaker;

  nsILineBreakerFactory *lf;
  nsresult rv = NS_OK;
  rv = nsServiceManager::GetService(kLWBrkCID,
                                    NS_GET_IID(nsILineBreakerFactory),
                                    (nsISupports **)&lf);
  if (NS_SUCCEEDED(rv))
  {
    nsAutoString lbarg;
    rv = lf->GetBreaker(lbarg, getter_AddRefs(lineBreaker));
    nsServiceManager::ReleaseService(kLWBrkCID, lf);
  }

  aOutString.SetLength(0);

  // Now we either have a line breaker, or we don't.
  PRInt32 length = aInString.Length();
  const PRUnichar* unicodeStr = aInString.GetUnicode();
  for (i = 0; i < length; )    // loop over lines
  {
    nsAutoString remaining(unicodeStr + i, length - i);

    // If there's a first-line offset, that means we're not starting
    // at the beginning of the line, so don't add a cite string there:
    if (!aFirstLineOffset)
      aOutString.Append(aLineStartStr);

    PRInt32 eol = i + aWrapCol - aFirstLineOffset;
    if (eol > length)
    {
      aOutString.Append(unicodeStr + i, length - i);
      aOutString.AppendWithConversion('\n');  // DOM line breaks, not NS_LINEBREAK
      break;
    }
    if (i > 0) aFirstLineOffset = 0;
    // eol is the prospective end of line ...
    // look backwards from there for a place to break.
    PRUint32 breakPt;
    PRBool needMore;
    rv = NS_ERROR_BASE;
    if (lineBreaker)
    {
      rv = lineBreaker->Prev(unicodeStr + i, length - i, eol - i,
                             &breakPt, &needMore);
      if (NS_FAILED(rv) || needMore)
      {
        rv = lineBreaker->Next(unicodeStr + i, length - i, eol - i,
                               &breakPt, &needMore);
        if (needMore) rv = NS_ERROR_BASE;
      }
    }
    // If we get out here and rv is set, something went wrong with line breaker.
    // Just break the line, hard.
    // If rv is okay, then breakPt is the place to break.
    if (NS_FAILED(rv))
    {
#ifdef DEBUG_akkana
      printf("nsILineBreaker not working -- breaking hard\n");
#endif
      breakPt = eol+1;
    }
    else breakPt += i;
    nsAutoString appending(unicodeStr + i, breakPt - i);
    aOutString.Append(unicodeStr + i, breakPt - i);
    aOutString.AppendWithConversion('\n');  // DOM line breaks, not NS_LINEBREAK

    i = breakPt;
  } // continue looping over lines

  return NS_OK;
}