Filters/FilterRTF.cs

   1
   2 //
   3 // Beagle
   4 //
   5 // FilterRTF.cs : Trivial implementation of a RTF-document filter.
   6 //
   7 // Copyright (C) 2004 Novell, Inc.
   8 //
   9 //
  10 // Permission is hereby granted, free of charge, to any person obtaining a
  11 // copy of this software and associated documentation files (the "Software"),
  12 // to deal in the Software without restriction, including without limitation
  13 // the rights to use, copy, modify, merge, publish, distribute, sublicense,
  14 // and/or sell copies of the Software, and to permit persons to whom the
  15 // Software is furnished to do so, subject to the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be included in
  18 // all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  21 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  22 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  23 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  25 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  26 // DEALINGS IN THE SOFTWARE.
  27 //
  28 //
  29 // Currently, the filtering is based on only few *control words*. If anyone
  30 // has any samples that can break this "assumption", kindly post a copy of it,
  31 // if you can, to <vvaradhan@novell.com>
  32 //
  33 // FIXME:  Require more complex samples to test the parsing, mostly generated
  34 //         using Microsoft Word or wordpad. :)
  35
  36 using System;
  37 using System.Collections;
  38 using System.IO;
  39 using System.Text;
  40
  41 using Beagle.Util;
  42 using Beagle.Daemon;
  43
  44 internal class RTFControlWordType {
  45
  46         public enum Type {
  47                 None,
  48                 Skip,
  49                 MetaDataBlock,
  50                 MetaDataTag,
  51                 Paragraph,
  52                 ParaEnd,
  53                 SplSection,
  54                 EscSeq,
  55                 CharProp
  56         }
  57
  58         public Type Types;
  59         public string ctrlWord;
  60
  61         RTFControlWordType (Type types, string ctrlword)
  62         {
  63                 this.Types = types;
  64                 this.ctrlWord = ctrlword;
  65         }
  66
  67         // FIXME: Need to add "unicode", "styles",
  68         // "header", "footer" etc.
  69         static RTFControlWordType[] types =
  70         {
  71                 new RTFControlWordType (Type.None, String.Empty),
  72                 new RTFControlWordType (Type.MetaDataBlock, "info"),
  73                 new RTFControlWordType (Type.MetaDataTag, "title"),
  74                 new RTFControlWordType (Type.MetaDataTag, "author"),
  75                 new RTFControlWordType (Type.MetaDataTag, "comment"),
  76                 new RTFControlWordType (Type.MetaDataTag, "operator"),
  77                 new RTFControlWordType (Type.MetaDataTag, "nofpages"),
  78                 new RTFControlWordType (Type.MetaDataTag, "nofwords"),
  79                 new RTFControlWordType (Type.MetaDataTag, "generator"),
  80                 new RTFControlWordType (Type.MetaDataTag, "company"),
  81                 new RTFControlWordType (Type.ParaEnd, "par"),
  82                 new RTFControlWordType (Type.Paragraph, "pard"),
  83                 new RTFControlWordType (Type.SplSection, "header"),
  84                 new RTFControlWordType (Type.SplSection, "footer"),
  85                 new RTFControlWordType (Type.SplSection, "headerl"),
  86                 new RTFControlWordType (Type.SplSection, "footerl"),
  87                 new RTFControlWordType (Type.SplSection, "footnote"),
  88                 new RTFControlWordType (Type.CharProp, "b"),
  89                 new RTFControlWordType (Type.CharProp, "i"),
  90                 new RTFControlWordType (Type.CharProp, "ul"),
  91                 new RTFControlWordType (Type.CharProp, "up"),
  92                 new RTFControlWordType (Type.CharProp, "dn"),
  93                 new RTFControlWordType (Type.Skip, "'"),
  94                 new RTFControlWordType (Type.Skip, "*"),
  95                 new RTFControlWordType (Type.EscSeq, "{"),
  96                 new RTFControlWordType (Type.EscSeq, "}"),
  97                 new RTFControlWordType (Type.EscSeq, "\\"),
  98         };
  99
 100         public static RTFControlWordType Find (string strCtrlWord)
 101         {
 102                 for (int i = 0; i < types.Length; i++) {
 103                         if (String.Compare (types[i].ctrlWord, strCtrlWord) == 0)
 104                                 return types[i];
 105                 }
 106                 return types[0];
 107         }
 108 }
 109 namespace Beagle.Filters {
 110
 111         public class FilterRTF : Beagle.Daemon.Filter {
 112
 113                 public enum Position {
 114                         None,
 115                         InMetaData,
 116                         InMetaDataTagGenerator,
 117                         InBody,
 118                         InPara
 119                 }
 120
 121                 public enum ErrorCodes {
 122                         ERROR_RTF_OK,
 123                         ERROR_RTF_EOF,
 124                         ERROR_RTF_UNHANDLED_SYMBOL
 125                 };
 126
 127                 Position pos;
 128                 int groupCount;
 129                 int skipCount;
 130                 int hotStyleCount;
 131                 bool bPartHotStyle;
 132                 FileStream FsRTF;
 133                 StreamReader SReaderRTF;
 134                 string partText;
 135
 136                 Stack MetaDataStack;
 137                 Stack TextDataStack;
 138
 139                 public FilterRTF ()
 140                 {
 141                         // Make this a general rtf filter.
 142                         AddSupportedFlavor (FilterFlavor.NewFromMimeType ("application/rtf"));
 143
 144                         pos = Position.None;
 145                         groupCount = 0;
 146                         skipCount = 0;
 147                         hotStyleCount = 0;
 148                         bPartHotStyle = false;
 149                         FsRTF = null;
 150                         SReaderRTF = null;
 151                         partText = String.Empty;
 152
 153                         MetaDataStack = new Stack ();
 154                         TextDataStack = new Stack ();
 155
 156                         SnippetMode = true;
 157                 }
 158
 159                 override protected void DoOpen (FileInfo info)
 160                 {
 161                         try {
 162                                 FsRTF = new FileStream (info.FullName, FileMode.Open,
 163                                                         FileAccess.Read);
 164                                 if (FsRTF != null)
 165                                         SReaderRTF = new StreamReader (FsRTF);
 166                                 else {
 167                                         Logger.Log.Error ("Unable to open {0}.", info.FullName);
 168                                         Finished ();
 169                                 }
 170                         } catch (Exception) {
 171                                 Logger.Log.Error ("Unable to open {0}.", info.FullName);
 172                                 Finished ();
 173                         }
 174
 175                 }
 176
 177                 // Identifies the type of RTF control word and handles accordingly
 178                 private ErrorCodes HandleControlWord (string strCtrlWord, int paramVal, bool bMeta)
 179                 {
 180                         RTFControlWordType ctrlWrdType = RTFControlWordType.Find (strCtrlWord);
 181
 182                         switch (ctrlWrdType.Types) {
 183                         case RTFControlWordType.Type.MetaDataBlock: /* process meta-data */
 184                                 pos = Position.InMetaData;
 185                                 break;
 186                         case RTFControlWordType.Type.MetaDataTag:
 187                                 if (pos == Position.InMetaData) {
 188                                         if (String.Compare (strCtrlWord, "title") == 0)
 189                                                 MetaDataStack.Push ("dc:title");
 190                                         else if (String.Compare (strCtrlWord, "author") == 0)
 191                                                 MetaDataStack.Push ("dc:author");
 192                                         else if (String.Compare (strCtrlWord, "comment") == 0)
 193                                                 MetaDataStack.Push ("fixme:comment");
 194                                         else if (String.Compare (strCtrlWord, "operator") == 0)
 195                                                 MetaDataStack.Push ("fixme:operator");
 196                                         else if (String.Compare (strCtrlWord, "nofpages") == 0) {
 197                                                 MetaDataStack.Push (Convert.ToString (paramVal));
 198                                                 MetaDataStack.Push ("fixme:page-count");
 199                                         }
 200                                         else if (String.Compare (strCtrlWord, "nofwords") == 0) {
 201                                                 MetaDataStack.Push (Convert.ToString (paramVal));
 202                                                 MetaDataStack.Push ("fixme:word-count");
 203                                         }
 204                                         else if (String.Compare (strCtrlWord, "company") == 0)
 205                                                 MetaDataStack.Push ("fixme:company");
 206                                 } else if (String.Compare (strCtrlWord, "generator") == 0) {
 207                                         pos = Position.InMetaDataTagGenerator;
 208                                         MetaDataStack.Push ("fixme:generator");
 209                                 }
 210                                 break;
 211
 212                         case RTFControlWordType.Type.Paragraph:
 213                                 if (!bMeta)
 214                                         pos = Position.InPara;
 215                                 break;
 216
 217                         case RTFControlWordType.Type.ParaEnd:
 218                                 if (!bMeta)
 219                                         pos = Position.InBody;
 220                                 break;
 221
 222                                 // FIXME: "Hot" styles are not *properly reset to normal*
 223                                 // on some *wierd* conditions.
 224                                 // To avoid such stuff, we need to maintain a stack of
 225                                 // groupCounts for set/reset Hot styles.
 226                         case RTFControlWordType.Type.SplSection:
 227                                 hotStyleCount = groupCount - 1;
 228                                 break;
 229
 230                         case RTFControlWordType.Type.CharProp:
 231                                 if (pos == Position.InPara) {
 232                                         if (paramVal < 0) {
 233                                                 //Console.WriteLine ("HotUp: \\{0}{1}", strCtrlWord, paramVal);
 234                                                 hotStyleCount = groupCount - 1;
 235                                                 //HotUp ();
 236                                         }
 237                                 }
 238                                 break;
 239
 240                         case RTFControlWordType.Type.EscSeq:
 241                                 if (pos == Position.InPara) {
 242                                         TextDataStack.Push (strCtrlWord);
 243                                         TextDataStack.Push ("EscSeq");
 244                                 }
 245                                 break;
 246                         case RTFControlWordType.Type.Skip:
 247                                 skipCount = groupCount - 1;
 248                                 //SkipDataStack.Push (groupCount-1);
 249                                 break;
 250                         }
 251                         return ErrorCodes.ERROR_RTF_OK;
 252                 }
 253
 254                 // FIXME: Probably need a little cleanup ;-)
 255
 256                 private ErrorCodes ProcessControlWords (bool bMeta)
 257                 {
 258                         int aByte = -1;
 259                         char ch;
 260                         int paramVal = -1;
 261                         bool negParamVal = false;
 262                         StringBuilder strCtrlWord = new StringBuilder ();
 263                         StringBuilder strParameter = new StringBuilder ();
 264
 265                         aByte = SReaderRTF.Read ();
 266                         if (aByte == -1)
 267                                 return ErrorCodes.ERROR_RTF_EOF;
 268
 269                         ch = (char) aByte;
 270                         RTFControlWordType ctrlWrdType = RTFControlWordType.Find (new String (ch, 1));
 271
 272                         if (!Char.IsLetter (ch) &&
 273                             ctrlWrdType.Types != RTFControlWordType.Type.Skip &&
 274                             ctrlWrdType.Types != RTFControlWordType.Type.EscSeq) {
 275                                 Logger.Log.Error ("Unhandled symbol: {0}, {1}", ch, ctrlWrdType.Types);
 276                                 return ErrorCodes.ERROR_RTF_UNHANDLED_SYMBOL;
 277                         }
 278                         while (aByte != -1) {
 279                                 strCtrlWord.Append (ch);
 280                                 aByte = SReaderRTF.Peek ();
 281                                 ch = (char) aByte;
 282                                 if (Char.IsLetter (ch)) {
 283                                         aByte = SReaderRTF.Read ();
 284                                         ch = (char) aByte;
 285                                 }
 286                                 else
 287                                         break;
 288                         }
 289                         aByte = SReaderRTF.Peek ();
 290                         ch = (char) aByte;
 291                         if (aByte != -1 && ch == '-') {
 292                                 negParamVal = true;
 293                                 aByte = SReaderRTF.Read (); // move the fp
 294                                 aByte = SReaderRTF.Peek ();
 295                                 ch = (char) aByte;
 296                         }
 297                         if (Char.IsDigit (ch)) {
 298                                 aByte = SReaderRTF.Read ();
 299                                 ch = (char) aByte;
 300                                 while (aByte != -1) {
 301                                         strParameter.Append (ch);
 302                                         aByte = SReaderRTF.Peek ();
 303                                         ch = (char) aByte;
 304                                         if (Char.IsDigit (ch)) {
 305                                                 aByte = SReaderRTF.Read ();
 306                                                 ch = (char) aByte;
 307                                         }
 308                                         else
 309                                                 break;
 310                                 }
 311                                 if (strParameter.Length > 0)
 312                                         paramVal = Convert.ToInt32 (strParameter.ToString());
 313                         }
 314                         //Console.WriteLine ("{0}\t{1}", strCtrlWord, strParameter);
 315                         if (negParamVal && paramVal > -1)
 316                                 paramVal *= -1;
 317                         return (HandleControlWord (strCtrlWord.ToString(), paramVal, bMeta));
 318                 }
 319
 320                 private ErrorCodes RTFParse (bool bMeta)
 321                 {
 322                         int aByte = -1;
 323                         char ch;
 324                         StringBuilder str = new StringBuilder ();
 325                         string strTemp = null;
 326                         ErrorCodes ec;
 327
 328                         while ((aByte = SReaderRTF.Read ()) != -1) {
 329                                 ch = (char) aByte;
 330                                 switch (ch) {
 331                                 case '\\': /* process keywords */
 332                                         if (skipCount > 0) {
 333                                                 if (groupCount > skipCount)
 334                                                         continue;
 335                                                 else
 336                                                         skipCount = 0;
 337                                         }
 338                                         ec = ProcessControlWords (bMeta);
 339                                         if (ec != ErrorCodes.ERROR_RTF_OK)
 340                                                 return ec;
 341                                         if (pos == Position.InPara)
 342                                                 AddTextForIndexing (str);
 343                                         str.Remove (0, str.Length);
 344                                         break;
 345                                 case '{': /* process groups */
 346                                         if (pos == Position.InPara)
 347                                                 AddTextForIndexing (str);
 348                                         str.Remove (0, str.Length);
 349                                         groupCount++;
 350                                         break;
 351                                 case '}': /* process groups */
 352                                         groupCount--;
 353                                         if (pos == Position.InMetaData ||
 354                                             pos == Position.InMetaDataTagGenerator) {
 355                                                 // groupCount will atleast be 1 for
 356                                                 // the outermost "{" block
 357                                                 if (pos == Position.InMetaData && groupCount == 1) {
 358                                                         if (bMeta)
 359                                                                 return ErrorCodes.ERROR_RTF_OK;
 360                                                 } else {
 361                                                         if (MetaDataStack.Count > 0) {
 362                                                                 strTemp = (string) MetaDataStack.Pop ();
 363                                                                 if ((String.Compare (strTemp, "fixme:word-count") == 0) ||
 364                                                                     (String.Compare (strTemp, "fixme:page-count") == 0)) {
 365                                                                         str.Append ((string) MetaDataStack.Pop ());
 366                                                                         AddProperty (Beagle.Property.NewUnsearched (strTemp,
 367                                                                                                                  str.ToString()));
 368                                                                 }
 369                                                                 else
 370                                                                         AddProperty (Beagle.Property.New (strTemp,
 371                                                                                                           str.ToString()));
 372                                                         }
 373                                                 }
 374
 375                                         } else if (pos == Position.InPara) {
 376                                                 AddTextForIndexing (str);
 377
 378                                         } else if (pos == Position.InBody) {
 379                                                 //Console.WriteLine ("\\par : {0}", str);
 380                                                 if (str.Length > 0)
 381                                                         str.Append (' ');
 382                                                 AddTextForIndexing (str);
 383                                                 AppendStructuralBreak ();
 384                                         }
 385                                         if (hotStyleCount > 0
 386                                             && groupCount <= hotStyleCount) {
 387                                                 //Console.WriteLine ("Group count: {0}, stack: {1}",
 388                                                 //groupCount, hotStyleCount);
 389                                                 HotDown ();
 390                                                 hotStyleCount = 0;
 391                                         }
 392
 393                                         break;
 394                                 case '\r': /* ignore \r */
 395                                 case '\n': /* ignore \n */
 396                                         break;
 397                                 default:
 398                                         if ((skipCount == 0 || groupCount <= skipCount)
 399                                             && (pos == Position.InPara || pos == Position.InBody))
 400                                                 str.Append (ch);
 401                                         break;
 402                                 }
 403                         }
 404                         if (partText.Length > 0) {
 405                                 if (bPartHotStyle && !IsHot)
 406                                         HotUp ();
 407                                 AppendText (partText);
 408                                 if (IsHot)
 409                                         HotDown ();
 410                         }
 411                         return ErrorCodes.ERROR_RTF_OK;
 412                 }
 413
 414                 private void AddTextForIndexing (StringBuilder str)
 415                 {
 416                         string strTemp;
 417                         string paramStr = null;
 418
 419                         bool wasHot = false;
 420
 421                         while (TextDataStack.Count > 0) {
 422                                 strTemp = (string) TextDataStack.Pop ();
 423                                 switch (strTemp) {
 424                                 case "EscSeq":
 425                                         strTemp = (string) TextDataStack.Pop ();
 426                                         str.Append (strTemp);
 427                                         break;
 428                                 }
 429                         }
 430
 431                         strTemp = String.Empty;
 432                         if (str.Length > 0) {
 433                                 //Console.WriteLine ("Text: [{0}]", str);
 434
 435                                 paramStr = str.ToString ();
 436                                 str.Remove (0, str.Length);
 437
 438                                 int index = paramStr.LastIndexOf (' ');
 439                                 int sindex = 0;
 440
 441                                 if (index > -1) {
 442                                         // During the previous-parsing, a word got terminatted partially,
 443                                         // find the remaining part of the word, concatenate it and add it to
 444                                         // the respective pools and reset the HOT status, if required.
 445                                         if (partText.Length > 0) {
 446                                                 sindex = paramStr.IndexOf (' ');
 447                                                 strTemp = partText + paramStr.Substring (0, sindex);
 448                                                 //Console.WriteLine ("PartHotStyle: {0}, HotStyleCount: {1}, partText: {2}",
 449                                                 //   bPartHotStyle,
 450                                                 //         hotStyleCount, strTemp);
 451                                                 if (!IsHot) {
 452                                                         if (bPartHotStyle)
 453                                                                 HotUp ();
 454                                                 }
 455                                                 else
 456                                                         wasHot = true;
 457
 458                                                 AppendText (strTemp);
 459                                                 if (!wasHot && bPartHotStyle)
 460                                                         HotDown ();
 461                                                 bPartHotStyle = false;
 462                                         }
 463                                         paramStr = paramStr.Substring (sindex);
 464                                         index = paramStr.LastIndexOf (' ');
 465                                         sindex = 0;
 466                                 }
 467                                 if (index > -1) {
 468                                         partText = paramStr.Substring (index);
 469                                         paramStr = paramStr.Substring (sindex, index);
 470                                 } else {
 471                                         strTemp = partText + paramStr;
 472                                         partText = strTemp;
 473                                         paramStr = String.Empty;
 474                                         strTemp = String.Empty;
 475                                 }
 476
 477                                 // Enable *HOT* just before appending the text
 478                                 // because, there can be some *Partial Texts* without
 479                                 // *HOT* styles that needs to be appended.
 480                                 if (hotStyleCount > 0) {
 481                                         if (!IsHot)
 482                                                 HotUp ();
 483                                         bPartHotStyle = true;
 484                                 } else
 485                                         bPartHotStyle |= false;
 486
 487                                 AppendText (paramStr);
 488
 489                                 if (partText.Length < 1)
 490                                         bPartHotStyle = false;
 491                         }
 492                 }
 493
 494                 override protected void DoPull ()
 495                 {
 496                         ErrorCodes ec;
 497                         ec = ErrorCodes.ERROR_RTF_OK;
 498                         pos = Position.None;
 499
 500                         // Discard the buffered data, if not,
 501                         // the buffered data can change the
 502                         // state "pos" variable that results
 503                         // in complete mess.
 504                         // Fixes: http://bugzilla.gnome.org/show_bug.cgi?id=172294
 505                         SReaderRTF.DiscardBufferedData ();
 506
 507                         // Rewind the file pointer to start from beginning.
 508                         SReaderRTF.BaseStream.Seek (0, SeekOrigin.Begin);
 509
 510                         ec = RTFParse (false);
 511                         if (ec != ErrorCodes.ERROR_RTF_OK)
 512                                 Logger.Log.Error ("{0}", ec);
 513                         Finished ();
 514                 }
 515
 516                 override protected void DoPullProperties ()
 517                 {
 518                         ErrorCodes ec;
 519                         ec = ErrorCodes.ERROR_RTF_OK;
 520                         ec = RTFParse (true);
 521                         if (ec != ErrorCodes.ERROR_RTF_OK)
 522                                 Logger.Log.Error ("{0}", ec);
 523                 }
 524
 525         }
 526 }