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| 1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file | |
| 2 // for details. All rights reserved. Use of this source code is governed by a | |
| 3 // BSD-style license that can be found in the LICENSE file. | |
| 4 | |
| 5 // Interface for decoders decoding binary data into string data. The | |
| 6 // decoder keeps track of line breaks during decoding. | |
| 7 abstract class _StringDecoder { | |
| 8 // Add more binary data to be decoded. The ownership of the buffer | |
| 9 // is transfered to the decoder and the caller most not modify it any more. | |
| 10 int write(List<int> buffer); | |
| 11 | |
| 12 // Returns whether any decoded data is available. | |
| 13 bool get isEmpty; | |
| 14 | |
| 15 // Returns the number of available decoded characters. | |
| 16 int available(); | |
| 17 | |
| 18 // Get the number of line breaks present in the current decoded | |
| 19 // data. | |
| 20 int get lineBreaks; | |
| 21 | |
| 22 // Get up to [len] characters of string data decoded since the last | |
| 23 // call to [decode] or [decodeLine]. Returns null if no decoded data | |
| 24 // is available. If [len] is not specified all decoded characters | |
| 25 // are returned. | |
| 26 String decoded([int len]); | |
| 27 | |
| 28 // Get the string data decoded since the last call to [decode] or | |
| 29 // [decodeLine] up to the next line break present. Returns null if | |
| 30 // no line break is present. The line break character sequence is | |
| 31 // discarded. | |
| 32 String get decodedLine; | |
| 33 } | |
| 34 | |
| 35 | |
| 36 class _StringDecoders { | |
| 37 static _StringDecoder decoder(Encoding encoding) { | |
| 38 if (encoding == Encoding.UTF_8) { | |
| 39 return new _UTF8Decoder(); | |
| 40 } else if (encoding == Encoding.ISO_8859_1) { | |
| 41 return new _Latin1Decoder(); | |
| 42 } else if (encoding == Encoding.ASCII) { | |
| 43 return new _AsciiDecoder(); | |
| 44 } else { | |
| 45 if (encoding is Encoding) { | |
| 46 throw new StreamException("Unsupported encoding ${encoding.name}"); | |
| 47 } else { | |
| 48 throw new StreamException("Unsupported encoding ${encoding}"); | |
| 49 } | |
| 50 } | |
| 51 } | |
| 52 } | |
| 53 | |
| 54 | |
| 55 class DecoderException implements Exception { | |
| 56 const DecoderException([String this.message]); | |
| 57 String toString() => "DecoderException: $message"; | |
| 58 final String message; | |
| 59 } | |
| 60 | |
| 61 | |
| 62 // Utility class for decoding UTF-8 from data delivered as a stream of | |
| 63 // bytes. | |
| 64 class _StringDecoderBase implements _StringDecoder { | |
| 65 _StringDecoderBase() | |
| 66 : _bufferList = new _BufferList(), | |
| 67 _result = new List<int>(), | |
| 68 _lineBreakEnds = new Queue<int>(); | |
| 69 | |
| 70 int write(List<int> buffer) { | |
| 71 _bufferList.add(buffer); | |
| 72 // Decode as many bytes into characters as possible. | |
| 73 while (_bufferList.length > 0) { | |
| 74 if (!_processNext()) { | |
| 75 break; | |
| 76 } | |
| 77 } | |
| 78 return buffer.length; | |
| 79 } | |
| 80 | |
| 81 bool get isEmpty => _result.isEmpty; | |
| 82 | |
| 83 int get lineBreaks => _lineBreaks; | |
| 84 | |
| 85 String decoded([int len]) { | |
| 86 if (isEmpty) return null; | |
| 87 | |
| 88 String result; | |
| 89 if (len !== null && len < available()) { | |
| 90 result = new String.fromCharCodes(_result.getRange(_resultOffset, len)); | |
| 91 } else { | |
| 92 if (_resultOffset == 0) { | |
| 93 result = new String.fromCharCodes(_result); | |
| 94 } else { | |
| 95 result = | |
| 96 new String.fromCharCodes( | |
| 97 _result.getRange(_resultOffset, | |
| 98 _result.length - _resultOffset)); | |
| 99 } | |
| 100 } | |
| 101 _resultOffset += result.length; | |
| 102 while (!_lineBreakEnds.isEmpty && | |
| 103 _lineBreakEnds.first < _charOffset + _resultOffset) { | |
| 104 _lineBreakEnds.removeFirst(); | |
| 105 _lineBreaks--; | |
| 106 } | |
| 107 if (_result.length == _resultOffset) _resetResult(); | |
| 108 return result; | |
| 109 } | |
| 110 | |
| 111 String get decodedLine { | |
| 112 if (_lineBreakEnds.isEmpty) return null; | |
| 113 int lineEnd = _lineBreakEnds.removeFirst(); | |
| 114 int terminationSequenceLength = 1; | |
| 115 if (_result[lineEnd - _charOffset] == LF && | |
| 116 lineEnd > _charOffset && | |
| 117 _resultOffset < lineEnd && | |
| 118 _result[lineEnd - _charOffset - 1] == CR) { | |
| 119 terminationSequenceLength = 2; | |
| 120 } | |
| 121 var lineLength = | |
| 122 lineEnd - _charOffset - _resultOffset - terminationSequenceLength + 1; | |
| 123 String result = | |
| 124 new String.fromCharCodes(_result.getRange(_resultOffset, lineLength)); | |
| 125 _lineBreaks--; | |
| 126 _resultOffset += (lineLength + terminationSequenceLength); | |
| 127 if (_result.length == _resultOffset) _resetResult(); | |
| 128 return result; | |
| 129 } | |
| 130 | |
| 131 // Add another decoded character. | |
| 132 void addChar(int charCode) { | |
| 133 _result.add(charCode); | |
| 134 _charCount++; | |
| 135 // Check for line ends (\r, \n and \r\n). | |
| 136 if (charCode == LF) { | |
| 137 _recordLineBreakEnd(_charCount - 1); | |
| 138 } else if (_lastCharCode == CR) { | |
| 139 _recordLineBreakEnd(_charCount - 2); | |
| 140 } | |
| 141 _lastCharCode = charCode; | |
| 142 } | |
| 143 | |
| 144 int available() => _result.length - _resultOffset; | |
| 145 | |
| 146 void _recordLineBreakEnd(int charPos) { | |
| 147 _lineBreakEnds.add(charPos); | |
| 148 _lineBreaks++; | |
| 149 } | |
| 150 | |
| 151 void _resetResult() { | |
| 152 _charOffset += _result.length; | |
| 153 _result = new List<int>(); | |
| 154 _resultOffset = 0; | |
| 155 } | |
| 156 | |
| 157 abstract bool _processNext(); | |
| 158 | |
| 159 _BufferList _bufferList; | |
| 160 int _resultOffset = 0; | |
| 161 List<int> _result; | |
| 162 int _lineBreaks = 0; // Number of line breaks in the current list. | |
| 163 // The positions of the line breaks are tracked in terms of absolute | |
| 164 // character positions from the begining of the decoded data. | |
| 165 Queue<int> _lineBreakEnds; // Character position of known line breaks. | |
| 166 int _charOffset = 0; // Character number of the first character in the list. | |
| 167 int _charCount = 0; // Total number of characters decoded. | |
| 168 int _lastCharCode = -1; | |
| 169 | |
| 170 final int LF = 10; | |
| 171 final int CR = 13; | |
| 172 } | |
| 173 | |
| 174 | |
| 175 // Utility class for decoding UTF-8 from data delivered as a stream of | |
| 176 // bytes. | |
| 177 class _UTF8Decoder extends _StringDecoderBase { | |
| 178 // Process the next UTF-8 encoded character. | |
| 179 bool _processNext() { | |
| 180 // Peek the next byte to calculate the number of bytes required for | |
| 181 // the next character. | |
| 182 int value = _bufferList.peek() & 0xFF; | |
| 183 if ((value & 0x80) == 0x80) { | |
| 184 int additionalBytes; | |
| 185 if ((value & 0xe0) == 0xc0) { // 110xxxxx | |
| 186 value = value & 0x1F; | |
| 187 additionalBytes = 1; | |
| 188 } else if ((value & 0xf0) == 0xe0) { // 1110xxxx | |
| 189 value = value & 0x0F; | |
| 190 additionalBytes = 2; | |
| 191 } else { // 11110xxx | |
| 192 value = value & 0x07; | |
| 193 additionalBytes = 3; | |
| 194 } | |
| 195 // Check if there are enough bytes to decode the character. Otherwise | |
| 196 // return false. | |
| 197 if (_bufferList.length < additionalBytes + 1) { | |
| 198 return false; | |
| 199 } | |
| 200 // Remove the value peeked from the buffer list. | |
| 201 _bufferList.next(); | |
| 202 for (int i = 0; i < additionalBytes; i++) { | |
| 203 int byte = _bufferList.next(); | |
| 204 value = value << 6 | (byte & 0x3F); | |
| 205 } | |
| 206 } else { | |
| 207 // Remove the value peeked from the buffer list. | |
| 208 _bufferList.next(); | |
| 209 } | |
| 210 addChar(value); | |
| 211 return true; | |
| 212 } | |
| 213 } | |
| 214 | |
| 215 | |
| 216 // Utility class for decoding ascii data delivered as a stream of | |
| 217 // bytes. | |
| 218 class _AsciiDecoder extends _StringDecoderBase { | |
| 219 // Process the next ascii encoded character. | |
| 220 bool _processNext() { | |
| 221 while (_bufferList.length > 0) { | |
| 222 int byte = _bufferList.next(); | |
| 223 if (byte > 127) { | |
| 224 throw new DecoderException("Illegal ASCII character $byte"); | |
| 225 } | |
| 226 addChar(byte); | |
| 227 } | |
| 228 return true; | |
| 229 } | |
| 230 } | |
| 231 | |
| 232 | |
| 233 // Utility class for decoding Latin-1 data delivered as a stream of | |
| 234 // bytes. | |
| 235 class _Latin1Decoder extends _StringDecoderBase { | |
| 236 // Process the next Latin-1 encoded character. | |
| 237 bool _processNext() { | |
| 238 while (_bufferList.length > 0) { | |
| 239 int byte = _bufferList.next(); | |
| 240 addChar(byte); | |
| 241 } | |
| 242 return true; | |
| 243 } | |
| 244 } | |
| 245 | |
| 246 | |
| 247 // Interface for encoders encoding string data into binary data. | |
| 248 abstract class _StringEncoder { | |
| 249 List<int> encodeString(String string); | |
| 250 } | |
| 251 | |
| 252 | |
| 253 // Utility class for encoding a string into UTF-8 byte stream. | |
| 254 class _UTF8Encoder implements _StringEncoder { | |
| 255 List<int> encodeString(String string) { | |
| 256 int size = _encodingSize(string); | |
| 257 List<int> result = new Uint8List(size); | |
| 258 _encodeString(string, result); | |
| 259 return result; | |
| 260 } | |
| 261 | |
| 262 static int _encodingSize(String string) => _encodeString(string, null); | |
| 263 | |
| 264 static int _encodeString(String string, List<int> buffer) { | |
| 265 int pos = 0; | |
| 266 int length = string.length; | |
| 267 for (int i = 0; i < length; i++) { | |
| 268 int additionalBytes; | |
| 269 int charCode = string.charCodeAt(i); | |
| 270 if (charCode <= 0x007F) { | |
| 271 additionalBytes = 0; | |
| 272 if (buffer != null) buffer[pos] = charCode; | |
| 273 } else if (charCode <= 0x07FF) { | |
| 274 // 110xxxxx (xxxxx is top 5 bits). | |
| 275 if (buffer != null) buffer[pos] = ((charCode >> 6) & 0x1F) | 0xC0; | |
| 276 additionalBytes = 1; | |
| 277 } else if (charCode <= 0xFFFF) { | |
| 278 // 1110xxxx (xxxx is top 4 bits) | |
| 279 if (buffer != null) buffer[pos] = ((charCode >> 12) & 0x0F)| 0xE0; | |
| 280 additionalBytes = 2; | |
| 281 } else { | |
| 282 // 11110xxx (xxx is top 3 bits) | |
| 283 if (buffer != null) buffer[pos] = ((charCode >> 18) & 0x07) | 0xF0; | |
| 284 additionalBytes = 3; | |
| 285 } | |
| 286 pos++; | |
| 287 if (buffer != null) { | |
| 288 for (int i = additionalBytes; i > 0; i--) { | |
| 289 // 10xxxxxx (xxxxxx is next 6 bits from the top). | |
| 290 buffer[pos++] = ((charCode >> (6 * (i - 1))) & 0x3F) | 0x80; | |
| 291 } | |
| 292 } else { | |
| 293 pos += additionalBytes; | |
| 294 } | |
| 295 } | |
| 296 return pos; | |
| 297 } | |
| 298 } | |
| 299 | |
| 300 | |
| 301 // Utility class for encoding a string into a Latin1 byte stream. | |
| 302 class _Latin1Encoder implements _StringEncoder { | |
| 303 List<int> encodeString(String string) { | |
| 304 List<int> result = new Uint8List(string.length); | |
| 305 for (int i = 0; i < string.length; i++) { | |
| 306 int charCode = string.charCodeAt(i); | |
| 307 if (charCode > 255) { | |
| 308 throw new EncoderException( | |
| 309 "No ISO_8859_1 encoding for code point $charCode"); | |
| 310 } | |
| 311 result[i] = charCode; | |
| 312 } | |
| 313 return result; | |
| 314 } | |
| 315 } | |
| 316 | |
| 317 | |
| 318 // Utility class for encoding a string into an ASCII byte stream. | |
| 319 class _AsciiEncoder implements _StringEncoder { | |
| 320 List<int> encodeString(String string) { | |
| 321 List<int> result = new Uint8List(string.length); | |
| 322 for (int i = 0; i < string.length; i++) { | |
| 323 int charCode = string.charCodeAt(i); | |
| 324 if (charCode > 127) { | |
| 325 throw new EncoderException( | |
| 326 "No ASCII encoding for code point $charCode"); | |
| 327 } | |
| 328 result[i] = charCode; | |
| 329 } | |
| 330 return result; | |
| 331 } | |
| 332 } | |
| 333 | |
| 334 | |
| 335 class _StringEncoders { | |
| 336 static _StringEncoder encoder(Encoding encoding) { | |
| 337 if (encoding == Encoding.UTF_8) { | |
| 338 return new _UTF8Encoder(); | |
| 339 } else if (encoding == Encoding.ISO_8859_1) { | |
| 340 return new _Latin1Encoder(); | |
| 341 } else if (encoding == Encoding.ASCII) { | |
| 342 return new _AsciiEncoder(); | |
| 343 } else { | |
| 344 throw new StreamException("Unsupported encoding ${encoding.name}"); | |
| 345 } | |
| 346 } | |
| 347 } | |
| 348 | |
| 349 | |
| 350 class EncoderException implements Exception { | |
| 351 const EncoderException([String this.message]); | |
| 352 String toString() => "EncoderException: $message"; | |
| 353 final String message; | |
| 354 } | |
| 355 | |
| 356 | |
| 357 class _StringInputStream implements StringInputStream { | |
| 358 _StringInputStream(InputStream this._input, Encoding this._encoding) { | |
| 359 _decoder = _StringDecoders.decoder(encoding); | |
| 360 _input.onData = _onData; | |
| 361 _input.onClosed = _onClosed; | |
| 362 } | |
| 363 | |
| 364 String read([int len]) { | |
| 365 String result = _decoder.decoded(len); | |
| 366 _checkInstallDataHandler(); | |
| 367 return result; | |
| 368 } | |
| 369 | |
| 370 String readLine() { | |
| 371 String decodedLine = _decoder.decodedLine; | |
| 372 if (decodedLine == null) { | |
| 373 if (_inputClosed) { | |
| 374 // Last line might not have a line separator. | |
| 375 decodedLine = _decoder.decoded(); | |
| 376 if (decodedLine != null && | |
| 377 decodedLine[decodedLine.length - 1] == '\r') { | |
| 378 decodedLine = decodedLine.substring(0, decodedLine.length - 1); | |
| 379 } | |
| 380 } | |
| 381 } | |
| 382 _checkInstallDataHandler(); | |
| 383 return decodedLine; | |
| 384 } | |
| 385 | |
| 386 int available() => _decoder.available(); | |
| 387 | |
| 388 Encoding get encoding => _encoding; | |
| 389 | |
| 390 bool get closed => _inputClosed && _decoder.isEmpty; | |
| 391 | |
| 392 void set onData(void callback()) { | |
| 393 _clientDataHandler = callback; | |
| 394 _clientLineHandler = null; | |
| 395 _checkInstallDataHandler(); | |
| 396 _checkScheduleCallback(); | |
| 397 } | |
| 398 | |
| 399 void set onLine(void callback()) { | |
| 400 _clientLineHandler = callback; | |
| 401 _clientDataHandler = null; | |
| 402 _checkInstallDataHandler(); | |
| 403 _checkScheduleCallback(); | |
| 404 } | |
| 405 | |
| 406 void set onClosed(void callback()) { | |
| 407 _clientCloseHandler = callback; | |
| 408 } | |
| 409 | |
| 410 void set onError(void callback(e)) { | |
| 411 _input.onError = callback; | |
| 412 } | |
| 413 | |
| 414 void _onData() { | |
| 415 _readData(); | |
| 416 if (!_decoder.isEmpty && _clientDataHandler !== null) { | |
| 417 _clientDataHandler(); | |
| 418 } | |
| 419 if (_decoder.lineBreaks > 0 && _clientLineHandler !== null) { | |
| 420 _clientLineHandler(); | |
| 421 } | |
| 422 _checkScheduleCallback(); | |
| 423 _checkInstallDataHandler(); | |
| 424 } | |
| 425 | |
| 426 void _onClosed() { | |
| 427 _inputClosed = true; | |
| 428 if (_decoder.isEmpty && _clientCloseHandler != null) { | |
| 429 _clientCloseHandler(); | |
| 430 _closed = true; | |
| 431 } else { | |
| 432 _checkScheduleCallback(); | |
| 433 } | |
| 434 } | |
| 435 | |
| 436 void _readData() { | |
| 437 List<int> data = _input.read(); | |
| 438 if (data !== null) { | |
| 439 _decoder.write(data); | |
| 440 } | |
| 441 } | |
| 442 | |
| 443 void _checkInstallDataHandler() { | |
| 444 if (_inputClosed || | |
| 445 (_clientDataHandler === null && _clientLineHandler === null)) { | |
| 446 _input.onData = null; | |
| 447 } else if (_clientDataHandler !== null) { | |
| 448 if (_decoder.isEmpty) { | |
| 449 _input.onData = _onData; | |
| 450 } else { | |
| 451 _input.onData = null; | |
| 452 } | |
| 453 } else { | |
| 454 assert(_clientLineHandler !== null); | |
| 455 if (_decoder.lineBreaks == 0) { | |
| 456 _input.onData = _onData; | |
| 457 } else { | |
| 458 _input.onData = null; | |
| 459 } | |
| 460 } | |
| 461 } | |
| 462 | |
| 463 // TODO(sgjesse): Find a better way of scheduling callbacks from | |
| 464 // the event loop. | |
| 465 void _checkScheduleCallback() { | |
| 466 void issueDataCallback(Timer timer) { | |
| 467 _scheduledDataCallback = null; | |
| 468 if (_clientDataHandler !== null) { | |
| 469 _clientDataHandler(); | |
| 470 _checkScheduleCallback(); | |
| 471 } | |
| 472 } | |
| 473 | |
| 474 void issueLineCallback(Timer timer) { | |
| 475 _scheduledLineCallback = null; | |
| 476 if (_clientLineHandler !== null) { | |
| 477 _clientLineHandler(); | |
| 478 _checkScheduleCallback(); | |
| 479 } | |
| 480 } | |
| 481 | |
| 482 void issueCloseCallback(Timer timer) { | |
| 483 _scheduledCloseCallback = null; | |
| 484 if (!_closed) { | |
| 485 if (_clientCloseHandler !== null) _clientCloseHandler(); | |
| 486 _closed = true; | |
| 487 } | |
| 488 } | |
| 489 | |
| 490 if (!_closed) { | |
| 491 // Schedule data callback if string data available. | |
| 492 if (_clientDataHandler != null && | |
| 493 !_decoder.isEmpty && | |
| 494 _scheduledDataCallback == null) { | |
| 495 if (_scheduledLineCallback != null) { | |
| 496 _scheduledLineCallback.cancel(); | |
| 497 } | |
| 498 _scheduledDataCallback = new Timer(0, issueDataCallback); | |
| 499 } | |
| 500 | |
| 501 // Schedule line callback if a line is available. | |
| 502 if (_clientLineHandler != null && | |
| 503 (_decoder.lineBreaks > 0 || (!_decoder.isEmpty && _inputClosed)) && | |
| 504 _scheduledLineCallback == null) { | |
| 505 if (_scheduledDataCallback != null) { | |
| 506 _scheduledDataCallback.cancel(); | |
| 507 } | |
| 508 _scheduledLineCallback = new Timer(0, issueLineCallback); | |
| 509 } | |
| 510 | |
| 511 // Schedule close callback if no more data and input is closed. | |
| 512 if (_decoder.isEmpty && | |
| 513 _inputClosed && | |
| 514 _scheduledCloseCallback == null) { | |
| 515 _scheduledCloseCallback = new Timer(0, issueCloseCallback); | |
| 516 } | |
| 517 } | |
| 518 } | |
| 519 | |
| 520 InputStream _input; | |
| 521 Encoding _encoding; | |
| 522 _StringDecoder _decoder; | |
| 523 bool _inputClosed = false; // Is the underlying input stream closed? | |
| 524 bool _closed = false; // Is this stream closed. | |
| 525 bool _eof = false; // Has all data been read from the decoder? | |
| 526 Timer _scheduledDataCallback; | |
| 527 Timer _scheduledLineCallback; | |
| 528 Timer _scheduledCloseCallback; | |
| 529 Function _clientDataHandler; | |
| 530 Function _clientLineHandler; | |
| 531 Function _clientCloseHandler; | |
| 532 } | |
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Chromium Code Reviews
Issue 11337019:
Use patching for dart:io. (Closed)
Base URL: https://dart.googlecode.com/svn/branches/bleeding_edge/dart