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lightning-sunbird  0.9+nobinonly
nsWrapUtils.cpp
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00001 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
00002 /* ***** BEGIN LICENSE BLOCK *****
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00037 
00038 #include "nsWrapUtils.h"
00039 
00040 #include "nsCOMPtr.h"
00041 
00042 // Line breaker stuff
00043 #include "nsIServiceManager.h"
00044 #include "nsILineBreakerFactory.h"
00045 #include "nsLWBrkCIID.h"
00046 
00047 /*
00048  * Rewrap the given section of string, putting the result in aOutString.
00049  */
00050 nsresult
00051 nsWrapUtils::Rewrap(const nsAString& aInString,
00052                          PRUint32 aWrapCol, PRUint32 aFirstLineOffset,
00053                          PRBool aRespectNewlines,
00054                          const nsAString &aLineStartStr,
00055                          nsAString& aOutString)
00056 {
00057   PRInt32 i;
00058 
00059   nsCOMPtr<nsILineBreaker> lineBreaker;
00060 
00061   nsILineBreakerFactory *lf;
00062   nsresult rv = CallGetService(NS_LWBRK_CONTRACTID, &lf);
00063   if (NS_SUCCEEDED(rv))
00064   {
00065     nsAutoString lbarg;
00066     lf->GetBreaker(lbarg, getter_AddRefs(lineBreaker));
00067     NS_RELEASE(lf);
00068   }
00069 
00070   aOutString.Truncate();
00071 
00072   // Now we either have a line breaker, or we don't.
00073   const nsPromiseFlatString &tString = PromiseFlatString(aInString);
00074   PRInt32 length = tString.Length();
00075   const PRUnichar* unicodeStr = tString.get();
00076   for (i = 0; i < length; )    // loop over lines
00077   {
00078     nsAutoString remaining(unicodeStr + i, length - i);
00079 
00080     // If there's a first-line offset, that means we're not starting
00081     // at the beginning of the line, so don't add a cite string there:
00082     if (!aFirstLineOffset)
00083       aOutString.Append(aLineStartStr);
00084 
00085     PRInt32 eol = i + aWrapCol - aFirstLineOffset;
00086     if (eol > length)
00087     {
00088       aOutString.Append(unicodeStr + i, length - i);
00089       aOutString.Append(PRUnichar('\n'));  // DOM line breaks, not NS_LINEBREAK
00090       break;
00091     }
00092     if (i > 0) aFirstLineOffset = 0;
00093     // eol is the prospective end of line ...
00094     // look backwards from there for a place to break.
00095     PRUint32 breakPt;
00096     PRBool needMore;
00097     rv = NS_ERROR_BASE;
00098     if (lineBreaker)
00099     {
00100       rv = lineBreaker->Prev(unicodeStr + i, length - i, eol - i,
00101                              &breakPt, &needMore);
00102       if (NS_FAILED(rv) || needMore)
00103       {
00104         rv = lineBreaker->Next(unicodeStr + i, length - i, eol - i,
00105                                &breakPt, &needMore);
00106         if (needMore) rv = NS_ERROR_BASE;
00107       }
00108     }
00109     // If we get out here and rv is set, something went wrong with line breaker.
00110     // Just break the line, hard.
00111     // If rv is okay, then breakPt is the place to break.
00112     if (NS_FAILED(rv))
00113     {
00114 #ifdef DEBUG_akkana
00115       printf("nsILineBreaker not working -- breaking hard\n");
00116 #endif
00117       breakPt = eol+1;
00118     }
00119     else breakPt += i;
00120     nsAutoString appending(unicodeStr + i, breakPt - i);
00121     aOutString.Append(unicodeStr + i, breakPt - i);
00122     aOutString.Append(PRUnichar('\n'));  // DOM line breaks, not NS_LINEBREAK
00123 
00124     i = breakPt;
00125   } // continue looping over lines
00126 
00127   return NS_OK;
00128 }
00129