RetroZilla/editor/libeditor/text/nsWrapUtils.cpp

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#include "nsWrapUtils.h"

#include "nsCOMPtr.h"

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

  nsCOMPtr<nsILineBreaker> lineBreaker;

  nsILineBreakerFactory *lf;
  nsresult rv = CallGetService(NS_LWBRK_CONTRACTID, &lf);
  if (NS_SUCCEEDED(rv))
  {
    nsAutoString lbarg;
    lf->GetBreaker(lbarg, getter_AddRefs(lineBreaker));
    NS_RELEASE(lf);
  }

  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.
    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.Append(PRUnichar('\n'));  // DOM line breaks, not NS_LINEBREAK

    i = breakPt;
  } // continue looping over lines

  return NS_OK;
}