mcs/class/System.XML/System.Xml/XmlTextReader.cs

   1 // -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*-\r
   2 //\r
   3 // System.Xml.XmlTextReader.cs\r
   4 //\r
   5 // Author:\r
   6 //   Jason Diamond (jason@injektilo.org)\r
   7 //\r
   8 // (C) 2001 Jason Diamond  http://injektilo.org/\r
   9 //\r
  10 \r
  11 // FIXME:\r
  12 //   This can only parse basic XML: elements, attributes, processing\r
  13 //   instructions, and comments are OK but there's no support for\r
  14 //   entity/character references or namespaces yet.\r
  15 //\r
  16 //   It barfs on DOCTYPE declarations and CDATA sections.\r
  17 //\r
  18 //   There's also no checking being done for either well-formedness\r
  19 //   or validity.\r
  20 //\r
  21 //   ParserContext and NameTables aren't being used yet.\r
  22 //\r
  23 //   The XmlTextReader-specific properties and methods have yet to\r
  24 //   be added or implemented.\r
  25 //\r
  26 //   Some thought needs to be given to performance. There's too many\r
  27 //   strings and string builders being allocated.\r
  28 //\r
  29 //   None of the MoveTo methods have been implemented yet.\r
  30 //\r
  31 //   LineNumber and LinePosition aren't being tracked.\r
  32 //\r
  33 //   xml:space, xml:lang, and xml:base aren't being tracked.\r
  34 //\r
  35 //   Depth isn't being tracked.\r
  36 \r
  37 using System;\r
  38 using System.Collections;\r
  39 using System.IO;\r
  40 using System.Net;\r
  41 using System.Text;\r
  42 \r
  43 namespace System.Xml\r
  44 {\r
  45         public class XmlTextReader : XmlReader\r
  46         {\r
  47                 // constructors\r
  48 \r
  49                 protected XmlTextReader()\r
  50                 {\r
  51                         Init();\r
  52                 }\r
  53 \r
  54                 public XmlTextReader(Stream input)\r
  55                 {\r
  56                         Init();\r
  57                         reader = new StreamReader(\r
  58                                 input,\r
  59                                 Encoding.UTF8,\r
  60                                 true);\r
  61                 }\r
  62 \r
  63                 public XmlTextReader(string url)\r
  64                 {\r
  65                         Init();\r
  66                         WebClient client = new WebClient();\r
  67                         reader = new StreamReader(\r
  68                                 client.OpenRead(url),\r
  69                                 Encoding.UTF8,\r
  70                                 true);\r
  71                 }\r
  72 \r
  73                 public XmlTextReader(TextReader input)\r
  74                 {\r
  75                         Init();\r
  76                         reader = input;\r
  77                 }\r
  78 \r
  79                 public XmlTextReader(Stream input, XmlNameTable nameTable)\r
  80                 {\r
  81                         // TODO: implement me.\r
  82                         throw new NotImplementedException();\r
  83                 }\r
  84 \r
  85                 public XmlTextReader(string baseURI, Stream input)\r
  86                 {\r
  87                         // TODO: implement me.\r
  88                         throw new NotImplementedException();\r
  89                 }\r
  90 \r
  91                 public XmlTextReader(string baseURI, TextReader input)\r
  92                 {\r
  93                         // TODO: implement me.\r
  94                         throw new NotImplementedException();\r
  95                 }\r
  96 \r
  97                 public XmlTextReader(string url, XmlNameTable nameTable)\r
  98                 {\r
  99                         // TODO: implement me.\r
 100                         throw new NotImplementedException();\r
 101                 }\r
 102 \r
 103                 public XmlTextReader(\r
 104                         TextReader input,\r
 105                         XmlNameTable nameTable)\r
 106                 {\r
 107                         // TODO: implement me.\r
 108                         throw new NotImplementedException();\r
 109                 }\r
 110 \r
 111                 public XmlTextReader(\r
 112                         Stream inputFragment,\r
 113                         XmlNodeType fragmentType,\r
 114                         XmlParserContext context)\r
 115                 {\r
 116                         // TODO: implement me.\r
 117                         throw new NotImplementedException();\r
 118                 }\r
 119 \r
 120                 public XmlTextReader(\r
 121                         string baseURI,\r
 122                         Stream input,\r
 123                         XmlNameTable nameTable)\r
 124                 {\r
 125                         // TODO: implement me.\r
 126                         throw new NotImplementedException();\r
 127                 }\r
 128 \r
 129                 public XmlTextReader(\r
 130                         string baseURI,\r
 131                         TextReader input,\r
 132                         XmlNameTable nameTable)\r
 133                 {\r
 134                         // TODO: implement me.\r
 135                         throw new NotImplementedException();\r
 136                 }\r
 137 \r
 138                 public XmlTextReader(\r
 139                         string fragment,\r
 140                         XmlNodeType fragmentType,\r
 141                         XmlParserContext context)\r
 142                 {\r
 143                         // TODO: implement me.\r
 144                         throw new NotImplementedException();\r
 145                 }\r
 146 \r
 147                 // properties\r
 148 \r
 149                 public override int AttributeCount\r
 150                 {\r
 151                         get\r
 152                         {\r
 153                                 return attributes.Count;\r
 154                         }\r
 155                 }\r
 156 \r
 157                 public override string BaseURI\r
 158                 {\r
 159                         get\r
 160                         {\r
 161                                 // TODO: implement me.\r
 162                                 return null;\r
 163                         }\r
 164                 }\r
 165 \r
 166                 public override bool CanResolveEntity\r
 167                 {\r
 168                         get\r
 169                         {\r
 170                                 // TODO: implement me.\r
 171                                 return false;\r
 172                         }\r
 173                 }\r
 174 \r
 175                 public override int Depth\r
 176                 {\r
 177                         get\r
 178                         {\r
 179                                 // TODO: implement me.\r
 180                                 return 0;\r
 181                         }\r
 182                 }\r
 183 \r
 184                 public override bool EOF\r
 185                 {\r
 186                         get\r
 187                         {\r
 188                                 return\r
 189                                         readState == ReadState.EndOfFile ||\r
 190                                         readState == ReadState.Closed;\r
 191                         }\r
 192                 }\r
 193 \r
 194                 public override bool HasValue\r
 195                 {\r
 196                         get\r
 197                         {\r
 198                                 return value != String.Empty;\r
 199                         }\r
 200                 }\r
 201 \r
 202                 public override bool IsDefault\r
 203                 {\r
 204                         get\r
 205                         {\r
 206                                 // TODO: implement me.\r
 207                                 return false;\r
 208                         }\r
 209                 }\r
 210 \r
 211                 public override bool IsEmptyElement\r
 212                 {\r
 213                         get\r
 214                         {\r
 215                                 return isEmptyElement;\r
 216                         }\r
 217                 }\r
 218 \r
 219                 public override string this[int i]\r
 220                 {\r
 221                         get\r
 222                         {\r
 223                                 return GetAttribute(i);\r
 224                         }\r
 225                 }\r
 226 \r
 227                 public override string this[string name]\r
 228                 {\r
 229                         get\r
 230                         {\r
 231                                 return GetAttribute(name);\r
 232                         }\r
 233                 }\r
 234 \r
 235                 public override string this[\r
 236                         string localName,\r
 237                         string namespaceName]\r
 238                 {\r
 239                         get\r
 240                         {\r
 241                                 return GetAttribute(localName, namespaceName);\r
 242                         }\r
 243                 }\r
 244 \r
 245                 public override string LocalName\r
 246                 {\r
 247                         get\r
 248                         {\r
 249                                 // TODO: implement me.\r
 250                                 return null;\r
 251                         }\r
 252                 }\r
 253 \r
 254                 public override string Name\r
 255                 {\r
 256                         get\r
 257                         {\r
 258                                 return name;\r
 259                         }\r
 260                 }\r
 261 \r
 262                 public override string NamespaceURI\r
 263                 {\r
 264                         get\r
 265                         {\r
 266                                 // TODO: implement me.\r
 267                                 return null;\r
 268                         }\r
 269                 }\r
 270 \r
 271                 public override XmlNameTable NameTable\r
 272                 {\r
 273                         get\r
 274                         {\r
 275                                 // TODO: implement me.\r
 276                                 return null;\r
 277                         }\r
 278                 }\r
 279 \r
 280                 public override XmlNodeType NodeType\r
 281                 {\r
 282                         get\r
 283                         {\r
 284                                 return nodeType;\r
 285                         }\r
 286                 }\r
 287 \r
 288                 public override string Prefix\r
 289                 {\r
 290                         get\r
 291                         {\r
 292                                 // TODO: implement me.\r
 293                                 return null;\r
 294                         }\r
 295                 }\r
 296 \r
 297                 public override char QuoteChar\r
 298                 {\r
 299                         get\r
 300                         {\r
 301                                 // TODO: implement me.\r
 302                                 return '"';\r
 303                         }\r
 304                 }\r
 305 \r
 306                 public override ReadState ReadState\r
 307                 {\r
 308                         get\r
 309                         {\r
 310                                 return readState;\r
 311                         }\r
 312                 }\r
 313 \r
 314                 public override string Value\r
 315                 {\r
 316                         get\r
 317                         {\r
 318                                 return value;\r
 319                         }\r
 320                 }\r
 321 \r
 322                 public override string XmlLang\r
 323                 {\r
 324                         get\r
 325                         {\r
 326                                 // TODO: implement me.\r
 327                                 return null;\r
 328                         }\r
 329                 }\r
 330 \r
 331                 public override XmlSpace XmlSpace\r
 332                 {\r
 333                         get\r
 334                         {\r
 335                                 // TODO: implement me.\r
 336                                 return XmlSpace.Default;\r
 337                         }\r
 338                 }\r
 339 \r
 340                 // methods\r
 341 \r
 342                 public override void Close()\r
 343                 {\r
 344                         readState = ReadState.Closed;\r
 345                 }\r
 346 \r
 347                 public override string GetAttribute(int i)\r
 348                 {\r
 349                         // TODO: implement me.\r
 350                         return null;\r
 351                 }\r
 352 \r
 353                 public override string GetAttribute(string name)\r
 354                 {\r
 355                         return (string)attributes[name];\r
 356                 }\r
 357 \r
 358                 public override string GetAttribute(\r
 359                         string localName,\r
 360                         string namespaceName)\r
 361                 {\r
 362                         // TODO: implement me.\r
 363                         return null;\r
 364                 }\r
 365 \r
 366                 public override string LookupNamespace(string prefix)\r
 367                 {\r
 368                         // TODO: implement me.\r
 369                         return null;\r
 370                 }\r
 371 \r
 372                 public override void MoveToAttribute(int i)\r
 373                 {\r
 374                         // TODO: implement me.\r
 375                 }\r
 376 \r
 377                 public override bool MoveToAttribute(string name)\r
 378                 {\r
 379                         // TODO: implement me.\r
 380                         return false;\r
 381                 }\r
 382 \r
 383                 public override bool MoveToAttribute(\r
 384                         string localName,\r
 385                         string namespaceName)\r
 386                 {\r
 387                         // TODO: implement me.\r
 388                         return false;\r
 389                 }\r
 390 \r
 391                 public override bool MoveToElement()\r
 392                 {\r
 393                         // TODO: implement me.\r
 394                         return false;\r
 395                 }\r
 396 \r
 397                 public override bool MoveToFirstAttribute()\r
 398                 {\r
 399                         // TODO: implement me.\r
 400                         return false;\r
 401                 }\r
 402 \r
 403                 public override bool MoveToNextAttribute()\r
 404                 {\r
 405                         // TODO: implement me.\r
 406                         return false;\r
 407                 }\r
 408 \r
 409                 public override bool Read()\r
 410                 {\r
 411                         bool more = false;\r
 412 \r
 413                         readState = ReadState.Interactive;\r
 414 \r
 415                         more = ReadContent();\r
 416 \r
 417                         return more;\r
 418                 }\r
 419 \r
 420                 public override bool ReadAttributeValue()\r
 421                 {\r
 422                         // TODO: implement me.\r
 423                         return false;\r
 424                 }\r
 425 \r
 426                 public override string ReadInnerXml()\r
 427                 {\r
 428                         // TODO: implement me.\r
 429                         return null;\r
 430                 }\r
 431 \r
 432                 public override string ReadOuterXml()\r
 433                 {\r
 434                         // TODO: implement me.\r
 435                         return null;\r
 436                 }\r
 437 \r
 438                 public override string ReadString()\r
 439                 {\r
 440                         // TODO: implement me.\r
 441                         return null;\r
 442                 }\r
 443 \r
 444                 public override void ResolveEntity()\r
 445                 {\r
 446                         // TODO: implement me.\r
 447                 }\r
 448 \r
 449                 // privates\r
 450 \r
 451                 private TextReader reader;\r
 452                 private ReadState readState;\r
 453 \r
 454                 private XmlNodeType nodeType;\r
 455                 private string name;\r
 456                 private bool isEmptyElement;\r
 457                 private string value;\r
 458                 private Hashtable attributes;\r
 459 \r
 460                 private void Init()\r
 461                 {\r
 462                         readState = ReadState.Initial;\r
 463 \r
 464                         nodeType = XmlNodeType.None;\r
 465                         name = String.Empty;\r
 466                         isEmptyElement = false;\r
 467                         value = String.Empty;\r
 468                         attributes = new Hashtable();\r
 469                 }\r
 470 \r
 471                 // Use this method rather than setting the properties\r
 472                 // directly so that all the necessary properties can\r
 473                 // be changed in harmony with each other. Maybe the\r
 474                 // fields should be in a seperate class to help enforce\r
 475                 // this.\r
 476                 private void SetProperties(\r
 477                         XmlNodeType nodeType,\r
 478                         string name,\r
 479                         bool isEmptyElement,\r
 480                         string value,\r
 481                         bool clearAttributes)\r
 482                 {\r
 483                         this.nodeType = nodeType;\r
 484                         this.name = name;\r
 485                         this.isEmptyElement = isEmptyElement;\r
 486                         this.value = value;\r
 487 \r
 488                         if (clearAttributes)\r
 489                         {\r
 490                                 ClearAttributes();\r
 491                         }\r
 492                 }\r
 493 \r
 494                 private void AddAttribute(string name, string value)\r
 495                 {\r
 496                         attributes.Add(name, value);\r
 497                 }\r
 498 \r
 499                 private void ClearAttributes()\r
 500                 {\r
 501                         attributes.Clear();\r
 502                 }\r
 503 \r
 504                 // This should really keep track of some state so\r
 505                 // that it's not possible to have more than one document\r
 506                 // element or text outside of the document element.\r
 507                 private bool ReadContent()\r
 508                 {\r
 509                         bool more = false;\r
 510 \r
 511                         switch (reader.Peek())\r
 512                         {\r
 513                         case '<':\r
 514                                 reader.Read();\r
 515                                 ReadTag();\r
 516                                 more = true;\r
 517                                 break;\r
 518                         case -1:\r
 519                                 readState = ReadState.EndOfFile;\r
 520                                 SetProperties(\r
 521                                         XmlNodeType.None, // nodeType\r
 522                                         String.Empty, // name\r
 523                                         false, // isEmptyElement\r
 524                                         String.Empty, // value\r
 525                                         true // clearAttributes\r
 526                                 );\r
 527                                 more = false;\r
 528                                 break;\r
 529                         default:\r
 530                                 ReadText();\r
 531                                 more = true;\r
 532                                 break;\r
 533                         }\r
 534 \r
 535                         return more;\r
 536                 }\r
 537 \r
 538                 // The leading '<' has already been consumed.\r
 539                 private void ReadTag()\r
 540                 {\r
 541                         switch (reader.Peek())\r
 542                         {\r
 543                         case '/':\r
 544                                 reader.Read();\r
 545                                 ReadEndTag();\r
 546                                 break;\r
 547                         case '?':\r
 548                                 reader.Read();\r
 549                                 ReadProcessingInstruction();\r
 550                                 break;\r
 551                         case '!':\r
 552                                 reader.Read();\r
 553                                 ReadComment();\r
 554                                 break;\r
 555                         default:\r
 556                                 ReadStartTag();\r
 557                                 break;\r
 558                         }\r
 559                 }\r
 560 \r
 561                 // The leading '<' has already been consumed.\r
 562                 private void ReadStartTag()\r
 563                 {\r
 564                         string name = ReadName();\r
 565                         SkipWhitespace();\r
 566 \r
 567                         bool isEmptyElement = false;\r
 568 \r
 569                         ClearAttributes();\r
 570 \r
 571                         if (XmlChar.IsFirstNameChar(reader.Peek()))\r
 572                         {\r
 573                                 ReadAttributes();\r
 574                         }\r
 575 \r
 576                         if (reader.Peek() == '/')\r
 577                         {\r
 578                                 reader.Read();\r
 579                                 isEmptyElement = true;\r
 580                         }\r
 581 \r
 582                         Expect('>');\r
 583 \r
 584                         SetProperties(\r
 585                                 XmlNodeType.Element, // nodeType\r
 586                                 name, // name\r
 587                                 isEmptyElement, // isEmptyElement\r
 588                                 String.Empty, // value\r
 589                                 false // clearAttributes\r
 590                         );\r
 591                 }\r
 592 \r
 593                 // The reader is positioned on the first character\r
 594                 // of the element's name.\r
 595                 private void ReadEndTag()\r
 596                 {\r
 597                         string name = ReadName();\r
 598                         SkipWhitespace();\r
 599                         Expect('>');\r
 600 \r
 601                         SetProperties(\r
 602                                 XmlNodeType.EndElement, // nodeType\r
 603                                 name, // name\r
 604                                 false, // isEmptyElement\r
 605                                 String.Empty, // value\r
 606                                 true // clearAttributes\r
 607                         );\r
 608                 }\r
 609 \r
 610                 // The reader is positioned on the first character\r
 611                 // of the text.\r
 612                 private void ReadText()\r
 613                 {\r
 614                         StringBuilder text = new StringBuilder();\r
 615                         text.Append((char)reader.Read());\r
 616 \r
 617                         while (reader.Peek() != '<' && reader.Peek() != -1)\r
 618                         {\r
 619                                 text.Append((char)reader.Read());\r
 620                         }\r
 621 \r
 622                         SetProperties(\r
 623                                 XmlNodeType.Text, // nodeType\r
 624                                 String.Empty, // name\r
 625                                 false, // isEmptyElement\r
 626                                 text.ToString(), // value\r
 627                                 true // clearAttributes\r
 628                         );\r
 629                 }\r
 630 \r
 631                 // The reader is positioned on the first character of\r
 632                 // the attribute name.\r
 633                 private void ReadAttributes()\r
 634                 {\r
 635                         do\r
 636                         {\r
 637                                 string name = ReadName();\r
 638                                 SkipWhitespace();\r
 639                                 Expect('=');\r
 640                                 SkipWhitespace();\r
 641                                 string value = ReadAttribute();\r
 642                                 SkipWhitespace();\r
 643 \r
 644                                 AddAttribute(name, value);\r
 645                         }\r
 646                         while (reader.Peek() != '/' && reader.Peek() != '>' && reader.Peek() != -1);\r
 647                 }\r
 648 \r
 649                 // The reader is positioned on the quote character.\r
 650                 private string ReadAttribute()\r
 651                 {\r
 652                         int quoteChar = reader.Read();\r
 653 \r
 654                         if (quoteChar != '\'' && quoteChar != '\"')\r
 655                         {\r
 656                                 throw new Exception("an attribute value was not quoted");\r
 657                         }\r
 658 \r
 659                         StringBuilder valueBuilder = new StringBuilder();\r
 660 \r
 661                         while (reader.Peek() != quoteChar)\r
 662                         {\r
 663                                 int ch = reader.Read();\r
 664 \r
 665                                 switch (ch)\r
 666                                 {\r
 667                                 case '<':\r
 668                                         throw new Exception("attribute values cannot contain '<'");\r
 669                                 case -1:\r
 670                                         throw new Exception("unexpected end of file in an attribute value");\r
 671                                 }\r
 672 \r
 673                                 valueBuilder.Append((char)ch);\r
 674                         }\r
 675 \r
 676                         reader.Read();\r
 677 \r
 678                         return valueBuilder.ToString();\r
 679                 }\r
 680 \r
 681                 // The reader is positioned on the first character\r
 682                 // of the target.\r
 683                 private void ReadProcessingInstruction()\r
 684                 {\r
 685                         string target = ReadName();\r
 686                         SkipWhitespace();\r
 687 \r
 688                         StringBuilder valueBuilder = new StringBuilder();\r
 689 \r
 690                         while (reader.Peek() != -1)\r
 691                         {\r
 692                                 int ch = reader.Read();\r
 693 \r
 694                                 if (ch == '?' && reader.Peek() == '>')\r
 695                                 {\r
 696                                         reader.Read();\r
 697                                         break;\r
 698                                 }\r
 699 \r
 700                                 valueBuilder.Append((char)ch);\r
 701                         }\r
 702 \r
 703                         SetProperties(\r
 704                                 XmlNodeType.ProcessingInstruction, // nodeType\r
 705                                 target, // name\r
 706                                 false, // isEmptyElement\r
 707                                 valueBuilder.ToString(), // value\r
 708                                 true // clearAttributes\r
 709                         );\r
 710                 }\r
 711 \r
 712                 // The reader is positioned on the first character after\r
 713                 // the leading '<!'.\r
 714                 private void ReadComment()\r
 715                 {\r
 716                         Expect('-');\r
 717                         Expect('-');\r
 718 \r
 719                         StringBuilder valueBuilder = new StringBuilder();\r
 720 \r
 721                         while (reader.Peek() != -1)\r
 722                         {\r
 723                                 int ch = reader.Read();\r
 724 \r
 725                                 if (ch == '-' && reader.Peek() == '-')\r
 726                                 {\r
 727                                         reader.Read();\r
 728 \r
 729                                         if (reader.Peek() != '>')\r
 730                                         {\r
 731                                                 throw new Exception("comments cannot contain '--'");\r
 732                                         }\r
 733 \r
 734                                         reader.Read();\r
 735                                         break;\r
 736                                 }\r
 737 \r
 738                                 valueBuilder.Append((char)ch);\r
 739                         }\r
 740 \r
 741                         SetProperties(\r
 742                                 XmlNodeType.Comment, // nodeType\r
 743                                 String.Empty, // name\r
 744                                 false, // isEmptyElement\r
 745                                 valueBuilder.ToString(), // value\r
 746                                 true // clearAttributes\r
 747                         );\r
 748                 }\r
 749 \r
 750                 // The reader is positioned on the first character\r
 751                 // of the name.\r
 752                 private string ReadName()\r
 753                 {\r
 754                         if (!XmlChar.IsFirstNameChar(reader.Peek()))\r
 755                         {\r
 756                                 throw new Exception("a name did not start with a legal character");\r
 757                         }\r
 758 \r
 759                         StringBuilder nameBuilder = new StringBuilder();\r
 760 \r
 761                         nameBuilder.Append((char)reader.Read());\r
 762 \r
 763                         while (XmlChar.IsNameChar(reader.Peek()))\r
 764                         {\r
 765                                 nameBuilder.Append((char)reader.Read());\r
 766                         }\r
 767 \r
 768                         return nameBuilder.ToString();\r
 769                 }\r
 770 \r
 771                 // Read the next character and compare it against the\r
 772                 // specified character.\r
 773                 private void Expect(int expected)\r
 774                 {\r
 775                         int ch = reader.Read();\r
 776 \r
 777                         if (ch != expected)\r
 778                         {\r
 779                                 throw new Exception(String.Format(\r
 780                                         "expected '{0}' ({1:X}) but found '{2}' ({3:X})",\r
 781                                         (char)expected,\r
 782                                         expected,\r
 783                                         (char)ch,\r
 784                                         ch));\r
 785                         }\r
 786                 }\r
 787 \r
 788                 // Does not consume the first non-whitespace character.\r
 789                 private void SkipWhitespace()\r
 790                 {\r
 791                         while (XmlChar.IsWhitespace(reader.Peek()))\r
 792                         {\r
 793                                 reader.Read();\r
 794                         }\r
 795                 }\r
 796         }\r
 797 }\r