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| 1 // Copyright 2014 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. |
| 4 |
| 5 #include "config.h" |
| 6 #include "core/css/parser/MediaQueryTokenizer.h" |
| 7 |
| 8 #include "core/css/parser/MediaQueryInputStream.h" |
| 9 #include "core/html/parser/HTMLParserIdioms.h" |
| 10 #include "wtf/unicode/CharacterNames.h" |
| 11 |
| 12 namespace WebCore { |
| 13 |
| 14 const unsigned codePointsNumber = SCHAR_MAX; |
| 15 |
| 16 class MediaQueryTokenizer::CodePoints { |
| 17 public: |
| 18 MediaQueryTokenizer::CodePoint codePoints[codePointsNumber]; |
| 19 |
| 20 CodePoints() |
| 21 { |
| 22 memset(codePoints, 0, codePointsNumber); |
| 23 codePoints['\n'] = &MediaQueryTokenizer::whiteSpace; |
| 24 codePoints['\r'] = &MediaQueryTokenizer::whiteSpace; |
| 25 codePoints['\t'] = &MediaQueryTokenizer::whiteSpace; |
| 26 codePoints[' '] = &MediaQueryTokenizer::whiteSpace; |
| 27 codePoints['\f'] = &MediaQueryTokenizer::whiteSpace; |
| 28 codePoints['('] = &MediaQueryTokenizer::leftParenthesis; |
| 29 codePoints[')'] = &MediaQueryTokenizer::rightParenthesis; |
| 30 codePoints['+'] = &MediaQueryTokenizer::plusOrFullStop; |
| 31 codePoints['.'] = &MediaQueryTokenizer::plusOrFullStop; |
| 32 codePoints[','] = &MediaQueryTokenizer::comma; |
| 33 codePoints['-'] = &MediaQueryTokenizer::hyphenMinus; |
| 34 codePoints['/'] = &MediaQueryTokenizer::solidus; |
| 35 codePoints[':'] = &MediaQueryTokenizer::colon; |
| 36 codePoints[';'] = &MediaQueryTokenizer::semiColon; |
| 37 codePoints['\\'] = &MediaQueryTokenizer::reverseSolidus; |
| 38 for (unsigned char digit = '0'; digit <= '9'; ++digit) |
| 39 codePoints[digit] = &MediaQueryTokenizer::asciiDigit; |
| 40 for (unsigned char alpha = 'a'; alpha <= 'z'; ++alpha) |
| 41 codePoints[alpha] = &MediaQueryTokenizer::nameStart; |
| 42 for (unsigned char alpha = 'A'; alpha <= 'Z'; ++alpha) |
| 43 codePoints[alpha] = &MediaQueryTokenizer::nameStart; |
| 44 codePoints['_'] = &MediaQueryTokenizer::nameStart; |
| 45 codePoints[kEndOfFileMarker] = &MediaQueryTokenizer::endOfFile; |
| 46 } |
| 47 }; |
| 48 |
| 49 MediaQueryTokenizer::CodePoints* MediaQueryTokenizer::codePoints() |
| 50 { |
| 51 static CodePoints codePoints; |
| 52 return &codePoints; |
| 53 } |
| 54 |
| 55 // http://dev.w3.org/csswg/css-syntax/#name-start-code-point |
| 56 static bool isNameStart(UChar c) |
| 57 { |
| 58 if (isASCIIAlpha(c)) |
| 59 return true; |
| 60 if (c == '_') |
| 61 return true; |
| 62 return !isASCII(c); |
| 63 } |
| 64 |
| 65 // http://www.w3.org/TR/css-syntax-3/#name-code-point |
| 66 static bool isNameChar(UChar c) |
| 67 { |
| 68 return isNameStart(c) || isASCIIDigit(c) || c == '-'; |
| 69 } |
| 70 |
| 71 // http://www.w3.org/TR/css-syntax-3/#check-if-two-code-points-are-a-valid-escap
e |
| 72 static bool twoCharsAreValidEscape(UChar first, UChar second) |
| 73 { |
| 74 return ((first == '\\') && (second != '\n') && (second != kEndOfFileMarker))
; |
| 75 } |
| 76 |
| 77 MediaQueryTokenizer::MediaQueryTokenizer() |
| 78 { |
| 79 } |
| 80 |
| 81 void MediaQueryTokenizer::reconsume(UChar c) |
| 82 { |
| 83 m_input->pushBack(c); |
| 84 } |
| 85 |
| 86 UChar MediaQueryTokenizer::consume() |
| 87 { |
| 88 UChar current = m_input->currentInputChar(); |
| 89 m_input->advance(); |
| 90 return current; |
| 91 } |
| 92 |
| 93 void MediaQueryTokenizer::consume(unsigned offset) |
| 94 { |
| 95 m_input->advance(offset); |
| 96 } |
| 97 |
| 98 MediaQueryToken MediaQueryTokenizer::whiteSpace(UChar cc) |
| 99 { |
| 100 // CSS Tokenization is currently lossy, but we could record |
| 101 // the exact whitespace instead of discarding it here. |
| 102 consumeUntilNonWhitespace(); |
| 103 return MediaQueryToken(WhitespaceToken); |
| 104 } |
| 105 |
| 106 MediaQueryToken MediaQueryTokenizer::leftParenthesis(UChar cc) |
| 107 { |
| 108 return MediaQueryToken(LeftParenthesisToken); |
| 109 } |
| 110 |
| 111 MediaQueryToken MediaQueryTokenizer::rightParenthesis(UChar cc) |
| 112 { |
| 113 return MediaQueryToken(RightParenthesisToken); |
| 114 } |
| 115 |
| 116 MediaQueryToken MediaQueryTokenizer::plusOrFullStop(UChar cc) |
| 117 { |
| 118 if (nextCharsAreNumber()) { |
| 119 reconsume(cc); |
| 120 return consumeNumericToken(); |
| 121 } |
| 122 return MediaQueryToken(DelimiterToken, cc); |
| 123 } |
| 124 |
| 125 MediaQueryToken MediaQueryTokenizer::comma(UChar cc) |
| 126 { |
| 127 return MediaQueryToken(CommaToken); |
| 128 } |
| 129 |
| 130 MediaQueryToken MediaQueryTokenizer::hyphenMinus(UChar cc) |
| 131 { |
| 132 if (nextCharsAreNumber()) { |
| 133 reconsume(cc); |
| 134 return consumeNumericToken(); |
| 135 } |
| 136 if (nextCharsAreIdentifier()) { |
| 137 reconsume(cc); |
| 138 return consumeIdentLikeToken(); |
| 139 } |
| 140 return MediaQueryToken(DelimiterToken, cc); |
| 141 } |
| 142 |
| 143 MediaQueryToken MediaQueryTokenizer::solidus(UChar cc) |
| 144 { |
| 145 return MediaQueryToken(DelimiterToken, cc); |
| 146 } |
| 147 |
| 148 MediaQueryToken MediaQueryTokenizer::colon(UChar cc) |
| 149 { |
| 150 return MediaQueryToken(ColonToken); |
| 151 } |
| 152 |
| 153 MediaQueryToken MediaQueryTokenizer::semiColon(UChar cc) |
| 154 { |
| 155 return MediaQueryToken(SemicolonToken); |
| 156 } |
| 157 |
| 158 MediaQueryToken MediaQueryTokenizer::reverseSolidus(UChar cc) |
| 159 { |
| 160 if (twoCharsAreValidEscape(cc, m_input->currentInputChar())) { |
| 161 reconsume(cc); |
| 162 return consumeIdentLikeToken(); |
| 163 } |
| 164 return MediaQueryToken(DelimiterToken, cc); |
| 165 } |
| 166 |
| 167 MediaQueryToken MediaQueryTokenizer::asciiDigit(UChar cc) |
| 168 { |
| 169 reconsume(cc); |
| 170 return consumeNumericToken(); |
| 171 } |
| 172 |
| 173 MediaQueryToken MediaQueryTokenizer::nameStart(UChar cc) |
| 174 { |
| 175 reconsume(cc); |
| 176 return consumeIdentLikeToken(); |
| 177 } |
| 178 |
| 179 MediaQueryToken MediaQueryTokenizer::endOfFile(UChar cc) |
| 180 { |
| 181 return MediaQueryToken(EOFToken); |
| 182 } |
| 183 |
| 184 void MediaQueryTokenizer::tokenize(String string, Vector<MediaQueryToken>& outTo
kens) |
| 185 { |
| 186 MediaQueryTokenizer tokenizer; |
| 187 // According to the spec, we should perform preprocessing here. |
| 188 // See: http://www.w3.org/TR/css-syntax-3/#input-preprocessing |
| 189 // |
| 190 // However, we can skip this step since: |
| 191 // * We're using HTML spaces (which accept \r and \f as a valid white space) |
| 192 // * Do not count white spaces |
| 193 // * consumeEscape replaces NULLs for replacement characters |
| 194 |
| 195 MediaQueryInputStream input(string); |
| 196 while (true) { |
| 197 outTokens.append(tokenizer.nextToken(input)); |
| 198 if (outTokens.last().type() == EOFToken) |
| 199 return; |
| 200 } |
| 201 } |
| 202 |
| 203 MediaQueryToken MediaQueryTokenizer::nextToken(MediaQueryInputStream& input) |
| 204 { |
| 205 // Unlike the HTMLTokenizer, the CSS Syntax spec is written |
| 206 // as a stateless, (fixed-size) look-ahead tokenizer. |
| 207 // We could move to the stateful model and instead create |
| 208 // states for all the "next 3 codepoints are X" cases. |
| 209 // State-machine tokenizers are easier to write to handle |
| 210 // incremental tokenization of partial sources. |
| 211 // However, for now we follow the spec exactly. |
| 212 m_input = &input; |
| 213 UChar cc = consume(); |
| 214 CodePoint codePointFunc = 0; |
| 215 |
| 216 if (isASCII(cc)) { |
| 217 ASSERT_WITH_SECURITY_IMPLICATION(cc < codePointsNumber); |
| 218 codePointFunc = codePoints()->codePoints[cc]; |
| 219 } else { |
| 220 codePointFunc = &MediaQueryTokenizer::nameStart; |
| 221 } |
| 222 |
| 223 if (codePointFunc) |
| 224 return ((this)->*(codePointFunc))(cc); |
| 225 |
| 226 return MediaQueryToken(DelimiterToken, cc); |
| 227 } |
| 228 |
| 229 // This method merges the following spec sections for efficiency |
| 230 // http://www.w3.org/TR/css3-syntax/#consume-a-number |
| 231 // http://www.w3.org/TR/css3-syntax/#convert-a-string-to-a-number |
| 232 MediaQueryToken MediaQueryTokenizer::consumeNumber() |
| 233 { |
| 234 ASSERT(nextCharsAreNumber()); |
| 235 NumericValueType type = IntegerValueType; |
| 236 double value = 0; |
| 237 int sign = 1; |
| 238 unsigned peekOffset = 0; |
| 239 int exponentSign = 1; |
| 240 unsigned exponentStartPos = 0; |
| 241 unsigned exponentEndPos = 0; |
| 242 unsigned fractionStartPos = 0; |
| 243 unsigned fractionEndPos = 0; |
| 244 unsigned long long integerPart; |
| 245 double fractionPart; |
| 246 unsigned fractionDigits; |
| 247 unsigned long long exponentPart; |
| 248 if (m_input->currentInputChar() == '+') { |
| 249 ++peekOffset; |
| 250 } else if (m_input->peek(peekOffset) == '-') { |
| 251 sign = -1; |
| 252 ++peekOffset; |
| 253 } |
| 254 unsigned intStartPos = peekOffset; |
| 255 peekOffset = m_input->skipWhilePredicate<isASCIIDigit>(peekOffset); |
| 256 unsigned intEndPos = peekOffset; |
| 257 if (m_input->peek(peekOffset) == '.' && isASCIIDigit(m_input->peek(++peekOff
set))) { |
| 258 fractionStartPos = peekOffset - 1; |
| 259 peekOffset = m_input->skipWhilePredicate<isASCIIDigit>(peekOffset); |
| 260 fractionEndPos = peekOffset; |
| 261 } |
| 262 if ((m_input->peek(peekOffset) == 'E' || m_input->peek(peekOffset) == 'e'))
{ |
| 263 int peekOffsetBeforeExponent = peekOffset; |
| 264 ++peekOffset; |
| 265 if (m_input->peek(peekOffset) == '+') { |
| 266 ++peekOffset; |
| 267 } else if (m_input->peek(peekOffset) =='-') { |
| 268 exponentSign = -1; |
| 269 ++peekOffset; |
| 270 } |
| 271 exponentStartPos = peekOffset; |
| 272 peekOffset = m_input->skipWhilePredicate<isASCIIDigit>(peekOffset); |
| 273 exponentEndPos = peekOffset; |
| 274 if (exponentEndPos == exponentStartPos) |
| 275 peekOffset = peekOffsetBeforeExponent; |
| 276 } |
| 277 integerPart = m_input->getUInt(intStartPos, intEndPos); |
| 278 fractionDigits = fractionEndPos - fractionStartPos; |
| 279 unsigned floatingFractionEndPos = fractionEndPos; |
| 280 fractionPart = m_input->getDouble(fractionStartPos, floatingFractionEndPos); |
| 281 exponentPart = m_input->getUInt(exponentStartPos, exponentEndPos); |
| 282 double exponent = pow(10, (float)exponentSign * (double)exponentPart); |
| 283 value = (double)sign * ((double)integerPart + fractionPart) * exponent; |
| 284 |
| 285 m_input->advance(peekOffset); |
| 286 if (fractionDigits > 0) |
| 287 type = NumberValueType; |
| 288 |
| 289 return MediaQueryToken(NumberToken, value, type); |
| 290 } |
| 291 |
| 292 // http://www.w3.org/TR/css3-syntax/#consume-a-numeric-token |
| 293 MediaQueryToken MediaQueryTokenizer::consumeNumericToken() |
| 294 { |
| 295 MediaQueryToken token = consumeNumber(); |
| 296 if (nextCharsAreIdentifier()) |
| 297 token.convertToDimensionWithUnit(consumeName()); |
| 298 else if (consumeIfNext('%')) |
| 299 token.convertToPercentage(); |
| 300 return token; |
| 301 } |
| 302 |
| 303 // http://www.w3.org/TR/css3-syntax/#consume-an-ident-like-token |
| 304 MediaQueryToken MediaQueryTokenizer::consumeIdentLikeToken() |
| 305 { |
| 306 String name = consumeName(); |
| 307 if (consumeIfNext('(')) |
| 308 return MediaQueryToken(FunctionToken, name); |
| 309 return MediaQueryToken(IdentToken, name); |
| 310 } |
| 311 |
| 312 void MediaQueryTokenizer::consumeUntilNonWhitespace() |
| 313 { |
| 314 // Using HTML space here rather than CSS space since we don't do preprocessi
ng |
| 315 while (isHTMLSpace<UChar>(m_input->currentInputChar())) |
| 316 consume(); |
| 317 } |
| 318 |
| 319 bool MediaQueryTokenizer::consumeIfNext(UChar character) |
| 320 { |
| 321 if (m_input->currentInputChar() == character) { |
| 322 consume(); |
| 323 return true; |
| 324 } |
| 325 return false; |
| 326 } |
| 327 |
| 328 // http://www.w3.org/TR/css3-syntax/#consume-a-name |
| 329 String MediaQueryTokenizer::consumeName() |
| 330 { |
| 331 // FIXME: Is this as efficient as it can be? |
| 332 // The possibility of escape chars mandates a copy AFAICT. |
| 333 Vector<UChar> result; |
| 334 while (true) { |
| 335 if (isNameChar(m_input->currentInputChar())) { |
| 336 result.append(consume()); |
| 337 continue; |
| 338 } |
| 339 if (nextTwoCharsAreValidEscape()) { |
| 340 // "consume()" fixes a spec bug. |
| 341 // The first code point should be consumed before consuming the esca
ped code point. |
| 342 consume(); |
| 343 result.append(consumeEscape()); |
| 344 continue; |
| 345 } |
| 346 return String(result); |
| 347 } |
| 348 } |
| 349 |
| 350 // http://www.w3.org/TR/css-syntax-3/#consume-an-escaped-code-point |
| 351 UChar MediaQueryTokenizer::consumeEscape() |
| 352 { |
| 353 UChar cc = consume(); |
| 354 ASSERT(cc != '\n'); |
| 355 if (isASCIIHexDigit(cc)) { |
| 356 unsigned consumedHexDigits = 1; |
| 357 String hexChars; |
| 358 do { |
| 359 hexChars.append(cc); |
| 360 cc = consume(); |
| 361 consumedHexDigits++; |
| 362 } while (consumedHexDigits < 6 && isASCIIHexDigit(cc)); |
| 363 bool ok = false; |
| 364 UChar codePoint = hexChars.toUIntStrict(&ok, 16); |
| 365 if (!ok) |
| 366 return WTF::Unicode::replacementCharacter; |
| 367 return codePoint; |
| 368 } |
| 369 |
| 370 // Replaces NULLs with replacement characters, since we do not perform prepr
ocessing |
| 371 if (cc == kEndOfFileMarker) |
| 372 return WTF::Unicode::replacementCharacter; |
| 373 return cc; |
| 374 } |
| 375 |
| 376 bool MediaQueryTokenizer::nextTwoCharsAreValidEscape() |
| 377 { |
| 378 return twoCharsAreValidEscape(m_input->peek(1), m_input->peek(2)); |
| 379 } |
| 380 |
| 381 // http://www.w3.org/TR/css3-syntax/#starts-with-a-number |
| 382 bool MediaQueryTokenizer::nextCharsAreNumber() |
| 383 { |
| 384 UChar first = m_input->currentInputChar(); |
| 385 UChar second = m_input->peek(1); |
| 386 if (isASCIIDigit(first)) |
| 387 return true; |
| 388 if (first == '+' || first == '-') |
| 389 return ((isASCIIDigit(second)) || (second == '.' && isASCIIDigit(m_input
->peek(2)))); |
| 390 if (first =='.') |
| 391 return (isASCIIDigit(second)); |
| 392 return false; |
| 393 } |
| 394 |
| 395 // http://www.w3.org/TR/css3-syntax/#would-start-an-identifier |
| 396 bool MediaQueryTokenizer::nextCharsAreIdentifier() |
| 397 { |
| 398 UChar firstChar = m_input->currentInputChar(); |
| 399 if (isNameStart(firstChar) || nextTwoCharsAreValidEscape()) |
| 400 return true; |
| 401 |
| 402 if (firstChar == '-') { |
| 403 if (isNameStart(m_input->peek(1))) |
| 404 return true; |
| 405 return twoCharsAreValidEscape(m_input->peek(1), m_input->peek(2)); |
| 406 } |
| 407 |
| 408 return false; |
| 409 } |
| 410 |
| 411 } // namespace WebCore |
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