diff -r 000000000000 -r 6474c204b198 layout/style/nsStyleUtil.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/layout/style/nsStyleUtil.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,577 @@
+/* -*- 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 "nsCSSProps.h"
+#include "nsRuleNode.h"
+#include "nsROCSSPrimitiveValue.h"
+#include "nsIContentPolicy.h"
+#include "nsIContentSecurityPolicy.h"
+#include "nsIURI.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) !=
+            char16_t('-')) {
+      // 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,
+                                         char16_t quoteChar)
+{
+  NS_PRECONDITION(quoteChar == '\'' || quoteChar == '"',
+                  "CSS strings must be quoted with ' or \"");
+  aReturn.Append(quoteChar);
+
+  const char16_t* in = aString.BeginReading();
+  const char16_t* 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(char16_t('\\'));
+      }
+      aReturn.Append(*in);
+    }
+  }
+
+  aReturn.Append(quoteChar);
+}
+
+/* static */ bool
+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 char16_t* in = aIdent.BeginReading();
+  const char16_t* const end = aIdent.EndReading();
+
+  if (in == end)
+    return true;
+
+  // 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(char16_t('-'));
+    ++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(char16_t('\\'));
+      aReturn.Append(char16_t('-'));
+    } else {
+      aReturn.AppendPrintf("\\%hX ", *in);
+    }
+    ++in;
+  }
+
+  for (; in != end; ++in) {
+    char16_t ch = *in;
+    if (ch == 0x00) {
+      return false;
+    }
+    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(char16_t('\\'));
+      }
+      aReturn.Append(ch);
+    }
+  }
+  return true;
+}
+
+/* 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(char16_t(' '));
+      }
+    }
+  }
+  NS_ABORT_IF_FALSE(aMaskedValue == 0, "unexpected bit remaining in bitfield");
+}
+
+/* static */ void
+nsStyleUtil::AppendAngleValue(const nsStyleCoord& aAngle, nsAString& aResult)
+{
+  MOZ_ASSERT(aAngle.IsAngleValue(), "Should have angle value");
+
+  // Append number.
+  AppendCSSNumber(aAngle.GetAngleValue(), aResult);
+
+  // Append unit.
+  switch (aAngle.GetUnit()) {
+    case eStyleUnit_Degree: aResult.AppendLiteral("deg");  break;
+    case eStyleUnit_Grad:   aResult.AppendLiteral("grad"); break;
+    case eStyleUnit_Radian: aResult.AppendLiteral("rad");  break;
+    case eStyleUnit_Turn:   aResult.AppendLiteral("turn"); break;
+    default: NS_NOTREACHED("unrecognized angle unit");
+  }
+}
+
+/* static */ void
+nsStyleUtil::AppendPaintOrderValue(uint8_t aValue,
+                                   nsAString& aResult)
+{
+  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.
+  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(char16_t(' '));
+        }
+
+        // append the previous functional value
+        aResult.Append(funcName);
+        aResult.Append(char16_t('('));
+        aResult.Append(funcParams);
+        aResult.Append(char16_t(')'));
+      }
+
+      // 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(char16_t(' '));
+    }
+
+    aResult.Append(funcName);
+    aResult.Append(char16_t('('));
+    aResult.Append(funcParams);
+    aResult.Append(char16_t(')'));
+  }
+}
+
+/* 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");
+      continue;
+    }
+    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(nsIContent* aContent,
+                                  nsIPrincipal* aPrincipal,
+                                  nsIURI* aSourceURI,
+                                  uint32_t aLineNumber,
+                                  const nsSubstring& aStyleText,
+                                  nsresult* aRv)
+{
+  nsresult rv;
+
+  if (aRv) {
+    *aRv = NS_OK;
+  }
+
+  MOZ_ASSERT(!aContent || aContent->Tag() == nsGkAtoms::style,
+      "aContent passed to CSPAllowsInlineStyle "
+      "for an element that is not <style>");
+
+  nsCOMPtr<nsIContentSecurityPolicy> csp;
+  rv = aPrincipal->GetCsp(getter_AddRefs(csp));
+
+  if (NS_FAILED(rv)) {
+    if (aRv)
+      *aRv = rv;
+    return false;
+  }
+
+  if (!csp) {
+    // No CSP --> the style is allowed
+    return true;
+  }
+
+  // An inline style can be allowed because all inline styles are allowed,
+  // or else because it is whitelisted by a nonce-source or hash-source. This
+  // is a logical OR between whitelisting methods, so the allowInlineStyle
+  // outparam can be reused for each check as long as we stop checking as soon
+  // as it is set to true. This also optimizes performance by avoiding the
+  // overhead of unnecessary checks.
+  bool allowInlineStyle = true;
+  nsAutoTArray<unsigned short, 3> violations;
+
+  bool reportInlineViolation;
+  rv = csp->GetAllowsInlineStyle(&reportInlineViolation, &allowInlineStyle);
+  if (NS_FAILED(rv)) {
+    if (aRv)
+      *aRv = rv;
+    return false;
+  }
+  if (reportInlineViolation) {
+    violations.AppendElement(static_cast<unsigned short>(
+          nsIContentSecurityPolicy::VIOLATION_TYPE_INLINE_STYLE));
+  }
+
+  nsAutoString nonce;
+  if (!allowInlineStyle) {
+    // We can only find a nonce if aContent is provided
+    bool foundNonce = !!aContent &&
+      aContent->GetAttr(kNameSpaceID_None, nsGkAtoms::nonce, nonce);
+    if (foundNonce) {
+      bool reportNonceViolation;
+      rv = csp->GetAllowsNonce(nonce, nsIContentPolicy::TYPE_STYLESHEET,
+                               &reportNonceViolation, &allowInlineStyle);
+      if (NS_FAILED(rv)) {
+        if (aRv)
+          *aRv = rv;
+        return false;
+      }
+
+      if (reportNonceViolation) {
+        violations.AppendElement(static_cast<unsigned short>(
+              nsIContentSecurityPolicy::VIOLATION_TYPE_NONCE_STYLE));
+      }
+    }
+  }
+
+  if (!allowInlineStyle) {
+    bool reportHashViolation;
+    rv = csp->GetAllowsHash(aStyleText, nsIContentPolicy::TYPE_STYLESHEET,
+                            &reportHashViolation, &allowInlineStyle);
+    if (NS_FAILED(rv)) {
+      if (aRv)
+        *aRv = rv;
+      return false;
+    }
+    if (reportHashViolation) {
+      violations.AppendElement(static_cast<unsigned short>(
+            nsIContentSecurityPolicy::VIOLATION_TYPE_HASH_STYLE));
+    }
+  }
+
+  // What violation(s) should be reported?
+  //
+  // 1. If the style tag has a nonce attribute, and the nonce does not match
+  // the policy, report VIOLATION_TYPE_NONCE_STYLE.
+  // 2. If the policy has at least one hash-source, and the hashed contents of
+  // the style tag did not match any of them, report VIOLATION_TYPE_HASH_STYLE
+  // 3. Otherwise, report VIOLATION_TYPE_INLINE_STYLE if appropriate.
+  //
+  // 1 and 2 may occur together, 3 should only occur by itself. Naturally,
+  // every VIOLATION_TYPE_NONCE_STYLE and VIOLATION_TYPE_HASH_STYLE are also
+  // VIOLATION_TYPE_INLINE_STYLE, but reporting the
+  // VIOLATION_TYPE_INLINE_STYLE is redundant and does not help the developer.
+  if (!violations.IsEmpty()) {
+    MOZ_ASSERT(violations[0] == nsIContentSecurityPolicy::VIOLATION_TYPE_INLINE_STYLE,
+               "How did we get any violations without an initial inline style violation?");
+    // This inline style is not allowed by CSP, so report the violation
+    nsAutoCString asciiSpec;
+    aSourceURI->GetAsciiSpec(asciiSpec);
+    nsAutoString styleSample(aStyleText);
+
+    // cap the length of the style sample at 40 chars.
+    if (styleSample.Length() > 40) {
+      styleSample.Truncate(40);
+      styleSample.AppendLiteral("...");
+    }
+
+    for (uint32_t i = 0; i < violations.Length(); i++) {
+      // Skip reporting the redundant inline style violation if there are
+      // other (nonce and/or hash violations) as well.
+      if (i > 0 || violations.Length() == 1) {
+        csp->LogViolationDetails(violations[i], NS_ConvertUTF8toUTF16(asciiSpec),
+                                 styleSample, aLineNumber, nonce, aStyleText);
+      }
+    }
+  }
+
+  if (!allowInlineStyle) {
+    NS_ASSERTION(!violations.IsEmpty(),
+        "CSP blocked inline style but is not reporting a violation");
+    // The inline style should be blocked.
+    return false;
+  }
+  // CSP allows inline styles.
+  return true;
+}