editor/libeditor/text/nsWrapUtils.cpp
author ted.mielczarek@gmail.com
Mon, 16 Jul 2007 14:00:26 -0700
changeset 3527 82217acf2a91b4c8076237352963a60278a6b61a
parent 1 9b2a99adc05e53cd4010de512f50118594756650
permissions -rw-r--r--
bug 388320 - package crashreporter xpt (+ rename airbag module to crashreporter). r=bsmedberg

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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#include "nsWrapUtils.h"

#include "nsCOMPtr.h"

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

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

  nsresult rv;
  nsCOMPtr<nsILineBreaker> lineBreaker = do_GetService(NS_LBRK_CONTRACTID, &rv);

  aOutString.Truncate();

  // Now we either have a line breaker, or we don't.
  const nsPromiseFlatString &tString = PromiseFlatString(aInString);
  PRInt32 length = tString.Length();
  const PRUnichar* unicodeStr = tString.get();
  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.Append(PRUnichar('\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.
    PRInt32 breakPt;
    rv = NS_ERROR_BASE;
    if (lineBreaker)
    {
      breakPt = lineBreaker->Prev(unicodeStr + i, length - i, eol - i);
      if (breakPt == NS_LINEBREAKER_NEED_MORE_TEXT)
      {
        breakPt = lineBreaker->Next(unicodeStr + i, length - i, eol - i);
        if (breakPt == NS_LINEBREAKER_NEED_MORE_TEXT) rv = NS_ERROR_BASE;
        else rv = NS_OK;
      }
      else rv = NS_OK;
    }
    // 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.Append(PRUnichar('\n'));  // DOM line breaks, not NS_LINEBREAK

    i = breakPt;
  } // continue looping over lines

  return NS_OK;
}