DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Header

Mercurial (5b81998bb7ab)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsStyleUtil.h"
#include "nsStyleConsts.h"

#include "nsIContent.h"
#include "nsReadableUtils.h"
#include "nsCSSProps.h"
#include "nsRuleNode.h"
#include "nsIContentSecurityPolicy.h"

using namespace mozilla;

//------------------------------------------------------------------------------
// Font Algorithm Code
//------------------------------------------------------------------------------

// Compare two language strings
bool nsStyleUtil::DashMatchCompare(const nsAString& aAttributeValue,
                                     const nsAString& aSelectorValue,
                                     const nsStringComparator& aComparator)
{
  bool result;
  uint32_t selectorLen = aSelectorValue.Length();
  uint32_t attributeLen = aAttributeValue.Length();
  if (selectorLen > attributeLen) {
    result = false;
  }
  else {
    nsAString::const_iterator iter;
    if (selectorLen != attributeLen &&
        *aAttributeValue.BeginReading(iter).advance(selectorLen) !=
            PRUnichar('-')) {
      // to match, the aAttributeValue must have a dash after the end of
      // the aSelectorValue's text (unless the aSelectorValue and the
      // aAttributeValue have the same text)
      result = false;
    }
    else {
      result = StringBeginsWith(aAttributeValue, aSelectorValue, aComparator);
    }
  }
  return result;
}

void nsStyleUtil::AppendEscapedCSSString(const nsAString& aString,
                                         nsAString& aReturn,
                                         PRUnichar quoteChar)
{
  NS_PRECONDITION(quoteChar == '\'' || quoteChar == '"',
                  "CSS strings must be quoted with ' or \"");
  aReturn.Append(quoteChar);

  const PRUnichar* in = aString.BeginReading();
  const PRUnichar* const end = aString.EndReading();
  for (; in != end; in++) {
    if (*in < 0x20 || (*in >= 0x7F && *in < 0xA0)) {
      // Escape U+0000 through U+001F and U+007F through U+009F numerically.
      aReturn.AppendPrintf("\\%hX ", *in);
    } else {
      if (*in == '"' || *in == '\'' || *in == '\\') {
        // Escape backslash and quote characters symbolically.
        // It's not technically necessary to escape the quote
        // character that isn't being used to delimit the string,
        // but we do it anyway because that makes testing simpler.
        aReturn.Append(PRUnichar('\\'));
      }
      aReturn.Append(*in);
    }
  }

  aReturn.Append(quoteChar);
}

/* static */ void
nsStyleUtil::AppendEscapedCSSIdent(const nsAString& aIdent, nsAString& aReturn)
{
  // The relevant parts of the CSS grammar are:
  //   ident    [-]?{nmstart}{nmchar}*
  //   nmstart  [_a-z]|{nonascii}|{escape}
  //   nmchar   [_a-z0-9-]|{nonascii}|{escape}
  //   nonascii [^\0-\177]
  //   escape   {unicode}|\\[^\n\r\f0-9a-f]
  //   unicode  \\[0-9a-f]{1,6}(\r\n|[ \n\r\t\f])?
  // from http://www.w3.org/TR/CSS21/syndata.html#tokenization

  const PRUnichar* in = aIdent.BeginReading();
  const PRUnichar* const end = aIdent.EndReading();

  if (in == end)
    return;

  // A leading dash does not need to be escaped as long as it is not the
  // *only* character in the identifier.
  if (in + 1 != end && *in == '-') {
    aReturn.Append(PRUnichar('-'));
    ++in;
  }

  // Escape a digit at the start (including after a dash),
  // numerically.  If we didn't escape it numerically, it would get
  // interpreted as a numeric escape for the wrong character.
  // A second dash immediately after a leading dash must also be
  // escaped, but this may be done symbolically.
  if (in != end && (*in == '-' ||
                    ('0' <= *in && *in <= '9'))) {
    if (*in == '-') {
      aReturn.Append(PRUnichar('\\'));
      aReturn.Append(PRUnichar('-'));
    } else {
      aReturn.AppendPrintf("\\%hX ", *in);
    }
    ++in;
  }

  for (; in != end; ++in) {
    PRUnichar ch = *in;
    if (ch < 0x20 || (0x7F <= ch && ch < 0xA0)) {
      // Escape U+0000 through U+001F and U+007F through U+009F numerically.
      aReturn.AppendPrintf("\\%hX ", *in);
    } else {
      // Escape ASCII non-identifier printables as a backslash plus
      // the character.
      if (ch < 0x7F &&
          ch != '_' && ch != '-' &&
          (ch < '0' || '9' < ch) &&
          (ch < 'A' || 'Z' < ch) &&
          (ch < 'a' || 'z' < ch)) {
        aReturn.Append(PRUnichar('\\'));
      }
      aReturn.Append(ch);
    }
  }
}

/* static */ void
nsStyleUtil::AppendBitmaskCSSValue(nsCSSProperty aProperty,
                                   int32_t aMaskedValue,
                                   int32_t aFirstMask,
                                   int32_t aLastMask,
                                   nsAString& aResult)
{
  for (int32_t mask = aFirstMask; mask <= aLastMask; mask <<= 1) {
    if (mask & aMaskedValue) {
      AppendASCIItoUTF16(nsCSSProps::LookupPropertyValue(aProperty, mask),
                         aResult);
      aMaskedValue &= ~mask;
      if (aMaskedValue) { // more left
        aResult.Append(PRUnichar(' '));
      }
    }
  }
  NS_ABORT_IF_FALSE(aMaskedValue == 0, "unexpected bit remaining in bitfield");
}

/* static */ void
nsStyleUtil::AppendPaintOrderValue(uint8_t aValue,
                                   nsAString& aResult)
{
  MOZ_STATIC_ASSERT
    (NS_STYLE_PAINT_ORDER_BITWIDTH * NS_STYLE_PAINT_ORDER_LAST_VALUE <= 8,
     "SVGStyleStruct::mPaintOrder and local variables not big enough");

  if (aValue == NS_STYLE_PAINT_ORDER_NORMAL) {
    aResult.AppendLiteral("normal");
    return;
  }

  // Append the minimal value necessary for the given paint order.
  MOZ_STATIC_ASSERT(NS_STYLE_PAINT_ORDER_LAST_VALUE == 3,
                    "paint-order values added; check serialization");

  // The following relies on the default order being the order of the
  // constant values.

  const uint8_t MASK = (1 << NS_STYLE_PAINT_ORDER_BITWIDTH) - 1;

  uint32_t lastPositionToSerialize = 0;
  for (uint32_t position = NS_STYLE_PAINT_ORDER_LAST_VALUE - 1;
       position > 0;
       position--) {
    uint8_t component =
      (aValue >> (position * NS_STYLE_PAINT_ORDER_BITWIDTH)) & MASK;
    uint8_t earlierComponent =
      (aValue >> ((position - 1) * NS_STYLE_PAINT_ORDER_BITWIDTH)) & MASK;
    if (component < earlierComponent) {
      lastPositionToSerialize = position - 1;
      break;
    }
  }

  for (uint32_t position = 0; position <= lastPositionToSerialize; position++) {
    if (position > 0) {
      aResult.AppendLiteral(" ");
    }
    uint8_t component = aValue & MASK;
    switch (component) {
      case NS_STYLE_PAINT_ORDER_FILL:
        aResult.AppendLiteral("fill");
        break;

      case NS_STYLE_PAINT_ORDER_STROKE:
        aResult.AppendLiteral("stroke");
        break;

      case NS_STYLE_PAINT_ORDER_MARKERS:
        aResult.AppendLiteral("markers");
        break;

      default:
        NS_NOTREACHED("unexpected paint-order component value");
    }
    aValue >>= NS_STYLE_PAINT_ORDER_BITWIDTH;
  }
}

/* static */ void
nsStyleUtil::AppendFontFeatureSettings(const nsTArray<gfxFontFeature>& aFeatures,
                                       nsAString& aResult)
{
  for (uint32_t i = 0, numFeat = aFeatures.Length(); i < numFeat; i++) {
    const gfxFontFeature& feat = aFeatures[i];

    if (i != 0) {
        aResult.AppendLiteral(", ");
    }

    // output tag
    char tag[7];
    tag[0] = '"';
    tag[1] = (feat.mTag >> 24) & 0xff;
    tag[2] = (feat.mTag >> 16) & 0xff;
    tag[3] = (feat.mTag >> 8) & 0xff;
    tag[4] = feat.mTag & 0xff;
    tag[5] = '"';
    tag[6] = 0;
    aResult.AppendASCII(tag);

    // output value, if necessary
    if (feat.mValue == 0) {
      // 0 ==> off
      aResult.AppendLiteral(" off");
    } else if (feat.mValue > 1) {
      aResult.AppendLiteral(" ");
      aResult.AppendInt(feat.mValue);
    }
    // else, omit value if 1, implied by default
  }
}

/* static */ void
nsStyleUtil::AppendFontFeatureSettings(const nsCSSValue& aSrc,
                                       nsAString& aResult)
{
  nsCSSUnit unit = aSrc.GetUnit();

  if (unit == eCSSUnit_Normal) {
    aResult.AppendLiteral("normal");
    return;
  }

  NS_PRECONDITION(unit == eCSSUnit_PairList || unit == eCSSUnit_PairListDep,
                  "improper value unit for font-feature-settings:");

  nsTArray<gfxFontFeature> featureSettings;
  nsRuleNode::ComputeFontFeatures(aSrc.GetPairListValue(), featureSettings);
  AppendFontFeatureSettings(featureSettings, aResult);
}

/* static */ void
nsStyleUtil::GetFunctionalAlternatesName(int32_t aFeature,
                                         nsAString& aFeatureName)
{
  aFeatureName.Truncate();
  nsCSSKeyword key =
    nsCSSProps::ValueToKeywordEnum(aFeature,
                           nsCSSProps::kFontVariantAlternatesFuncsKTable);

  NS_ASSERTION(key != eCSSKeyword_UNKNOWN, "bad alternate feature type");
  AppendUTF8toUTF16(nsCSSKeywords::GetStringValue(key), aFeatureName);
}

/* static */ void
nsStyleUtil::SerializeFunctionalAlternates(
    const nsTArray<gfxAlternateValue>& aAlternates,
    nsAString& aResult)
{
  nsAutoString funcName, funcParams;
  uint32_t numValues = aAlternates.Length();

  uint32_t feature = 0;
  for (uint32_t i = 0; i < numValues; i++) {
    const gfxAlternateValue& v = aAlternates.ElementAt(i);
    if (feature != v.alternate) {
      feature = v.alternate;
      if (!funcName.IsEmpty() && !funcParams.IsEmpty()) {
        if (!aResult.IsEmpty()) {
          aResult.Append(PRUnichar(' '));
        }

        // append the previous functional value
        aResult.Append(funcName);
        aResult.Append(PRUnichar('('));
        aResult.Append(funcParams);
        aResult.Append(PRUnichar(')'));
      }

      // function name
      GetFunctionalAlternatesName(v.alternate, funcName);
      NS_ASSERTION(!funcName.IsEmpty(), "unknown property value name");

      // function params
      funcParams.Truncate();
      AppendEscapedCSSIdent(v.value, funcParams);
    } else {
      if (!funcParams.IsEmpty()) {
        funcParams.Append(NS_LITERAL_STRING(", "));
      }
      AppendEscapedCSSIdent(v.value, funcParams);
    }
  }

    // append the previous functional value
  if (!funcName.IsEmpty() && !funcParams.IsEmpty()) {
    if (!aResult.IsEmpty()) {
      aResult.Append(PRUnichar(' '));
    }

    aResult.Append(funcName);
    aResult.Append(PRUnichar('('));
    aResult.Append(funcParams);
    aResult.Append(PRUnichar(')'));
  }
}

/* static */ void
nsStyleUtil::ComputeFunctionalAlternates(const nsCSSValueList* aList,
                                  nsTArray<gfxAlternateValue>& aAlternateValues)
{
  gfxAlternateValue v;

  aAlternateValues.Clear();
  for (const nsCSSValueList* curr = aList; curr != nullptr; curr = curr->mNext) {
    // list contains function units
    if (curr->mValue.GetUnit() != eCSSUnit_Function) {
      continue;
    }

    // element 0 is the propval in ident form
    const nsCSSValue::Array *func = curr->mValue.GetArrayValue();

    // lookup propval
    nsCSSKeyword key = func->Item(0).GetKeywordValue();
    NS_ASSERTION(key != eCSSKeyword_UNKNOWN, "unknown alternate property value");

    int32_t alternate;
    if (key == eCSSKeyword_UNKNOWN ||
        !nsCSSProps::FindKeyword(key,
                                 nsCSSProps::kFontVariantAlternatesFuncsKTable,
                                 alternate)) {
      NS_NOTREACHED("keyword not a font-variant-alternates value");
    }
    v.alternate = alternate;

    // other elements are the idents associated with the propval
    // append one alternate value for each one
    uint32_t numElems = func->Count();
    for (uint32_t i = 1; i < numElems; i++) {
      const nsCSSValue& value = func->Item(i);
      NS_ASSERTION(value.GetUnit() == eCSSUnit_Ident,
                   "weird unit found in variant alternate");
      if (value.GetUnit() != eCSSUnit_Ident) {
        continue;
      }
      value.GetStringValue(v.value);
      aAlternateValues.AppendElement(v);
    }
  }
}

/* static */ float
nsStyleUtil::ColorComponentToFloat(uint8_t aAlpha)
{
  // Alpha values are expressed as decimals, so we should convert
  // back, using as few decimal places as possible for
  // round-tripping.
  // First try two decimal places:
  float rounded = NS_roundf(float(aAlpha) * 100.0f / 255.0f) / 100.0f;
  if (FloatToColorComponent(rounded) != aAlpha) {
    // Use three decimal places.
    rounded = NS_roundf(float(aAlpha) * 1000.0f / 255.0f) / 1000.0f;
  }
  return rounded;
}

/* static */ bool
nsStyleUtil::IsSignificantChild(nsIContent* aChild, bool aTextIsSignificant,
                                bool aWhitespaceIsSignificant)
{
  NS_ASSERTION(!aWhitespaceIsSignificant || aTextIsSignificant,
               "Nonsensical arguments");

  bool isText = aChild->IsNodeOfType(nsINode::eTEXT);

  if (!isText && !aChild->IsNodeOfType(nsINode::eCOMMENT) &&
      !aChild->IsNodeOfType(nsINode::ePROCESSING_INSTRUCTION)) {
    return true;
  }

  return aTextIsSignificant && isText && aChild->TextLength() != 0 &&
         (aWhitespaceIsSignificant ||
          !aChild->TextIsOnlyWhitespace());
}

/* static */ bool
nsStyleUtil::CSPAllowsInlineStyle(nsIPrincipal* aPrincipal,
                                  nsIURI* aSourceURI,
                                  uint32_t aLineNumber,
                                  const nsSubstring& aStyleText,
                                  nsresult* aRv)
{
  nsresult rv;

  if (aRv) {
    *aRv = NS_OK;
  }

  nsCOMPtr<nsIContentSecurityPolicy> csp;
  rv = aPrincipal->GetCsp(getter_AddRefs(csp));

  if (NS_FAILED(rv)) {
    if (aRv)
      *aRv = rv;
    return false;
  }

  if (csp) {
    bool inlineOK = true;
    bool reportViolation = false;
    rv = csp->GetAllowsInlineStyle(&reportViolation, &inlineOK);
    if (NS_FAILED(rv)) {
      if (aRv)
        *aRv = rv;
      return false;
    }

    if (reportViolation) {
      // Inline styles are not allowed by CSP, so report the violation
      nsAutoCString asciiSpec;
      aSourceURI->GetAsciiSpec(asciiSpec);
      nsAutoString styleText(aStyleText);

      // cap the length of the style sample at 40 chars.
      if (styleText.Length() > 40) {
        styleText.Truncate(40);
        styleText.Append(NS_LITERAL_STRING("..."));
      }

      csp->LogViolationDetails(nsIContentSecurityPolicy::VIOLATION_TYPE_INLINE_STYLE,
                              NS_ConvertUTF8toUTF16(asciiSpec),
                              aStyleText,
                              aLineNumber);
    }

    if (!inlineOK) {
        // The inline style should be blocked.
        return false;
    }
  }
  // No CSP or a CSP that allows inline styles.
  return true;
}