The Tor Browser: layout/style/Declaration.cpp@97036ab72558 (annotated)

layout/style/Declaration.cpp@97036ab72558 (annotated)

layout/style/Declaration.cpp

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- 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/. */
 /*
  * representation of a declaration block (or style attribute) in a CSS
  * stylesheet
  */
 #include "mozilla/ArrayUtils.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/css/Declaration.h"
 #include "nsPrintfCString.h"
 #include "gfxFontConstants.h"
 #include "nsStyleUtil.h"
 namespace mozilla {
 namespace css {
 Declaration::Declaration()
   : mImmutable(false)
 {
   MOZ_COUNT_CTOR(mozilla::css::Declaration);
 }
 Declaration::Declaration(const Declaration& aCopy)
   : mOrder(aCopy.mOrder),
     mVariableOrder(aCopy.mVariableOrder),
     mData(aCopy.mData ? aCopy.mData->Clone() : nullptr),
     mImportantData(aCopy.mImportantData ?
                      aCopy.mImportantData->Clone() : nullptr),
     mVariables(aCopy.mVariables ?
         new CSSVariableDeclarations(*aCopy.mVariables) :
         nullptr),
     mImportantVariables(aCopy.mImportantVariables ?
         new CSSVariableDeclarations(*aCopy.mImportantVariables) :
         nullptr),
     mImmutable(false)
 {
   MOZ_COUNT_CTOR(mozilla::css::Declaration);
 }
 Declaration::~Declaration()
 {
   MOZ_COUNT_DTOR(mozilla::css::Declaration);
 }
 void
 Declaration::ValueAppended(nsCSSProperty aProperty)
 {
   NS_ABORT_IF_FALSE(!mData && !mImportantData,
                     "should only be called while expanded");
   NS_ABORT_IF_FALSE(!nsCSSProps::IsShorthand(aProperty),
                     "shorthands forbidden");
   // order IS important for CSS, so remove and add to the end
   mOrder.RemoveElement(static_cast<uint32_t>(aProperty));
   mOrder.AppendElement(static_cast<uint32_t>(aProperty));
 }
 void
 Declaration::RemoveProperty(nsCSSProperty aProperty)
 {
   MOZ_ASSERT(0 <= aProperty && aProperty < eCSSProperty_COUNT);
   nsCSSExpandedDataBlock data;
   ExpandTo(&data);
   NS_ABORT_IF_FALSE(!mData && !mImportantData, "Expand didn't null things out");
   if (nsCSSProps::IsShorthand(aProperty)) {
     CSSPROPS_FOR_SHORTHAND_SUBPROPERTIES(p, aProperty) {
       data.ClearLonghandProperty(*p);
       mOrder.RemoveElement(static_cast<uint32_t>(*p));
     }
   } else {
     data.ClearLonghandProperty(aProperty);
     mOrder.RemoveElement(static_cast<uint32_t>(aProperty));
   }
   CompressFrom(&data);
 }
 bool
 Declaration::HasProperty(nsCSSProperty aProperty) const
 {
   NS_ABORT_IF_FALSE(0 <= aProperty &&
                     aProperty < eCSSProperty_COUNT_no_shorthands,
                     "property ID out of range");
   nsCSSCompressedDataBlock *data = GetValueIsImportant(aProperty)
                                       ? mImportantData : mData;
   const nsCSSValue *val = data->ValueFor(aProperty);
   return !!val;
 }
 bool
 Declaration::AppendValueToString(nsCSSProperty aProperty,
                                  nsAString& aResult,
                                  nsCSSValue::Serialization aSerialization) const
 {
   NS_ABORT_IF_FALSE(0 <= aProperty &&
                     aProperty < eCSSProperty_COUNT_no_shorthands,
                     "property ID out of range");
   nsCSSCompressedDataBlock *data = GetValueIsImportant(aProperty)
                                       ? mImportantData : mData;
   const nsCSSValue *val = data->ValueFor(aProperty);
   if (!val) {
     return false;
   }
   val->AppendToString(aProperty, aResult, aSerialization);
   return true;
 }
 // Helper to append |aString| with the shorthand sides notation used in e.g.
 // 'padding'. |aProperties| and |aValues| are expected to have 4 elements.
 static void
 AppendSidesShorthandToString(const nsCSSProperty aProperties[],
                              const nsCSSValue* aValues[],
                              nsAString& aString,
                              nsCSSValue::Serialization aSerialization)
 {
   const nsCSSValue& value1 = *aValues[0];
   const nsCSSValue& value2 = *aValues[1];
   const nsCSSValue& value3 = *aValues[2];
   const nsCSSValue& value4 = *aValues[3];
   NS_ABORT_IF_FALSE(value1.GetUnit() != eCSSUnit_Null, "null value 1");
   value1.AppendToString(aProperties[0], aString, aSerialization);
   if (value1 != value2 || value1 != value3 || value1 != value4) {
     aString.Append(char16_t(' '));
     NS_ABORT_IF_FALSE(value2.GetUnit() != eCSSUnit_Null, "null value 2");
     value2.AppendToString(aProperties[1], aString, aSerialization);
     if (value1 != value3 || value2 != value4) {
       aString.Append(char16_t(' '));
       NS_ABORT_IF_FALSE(value3.GetUnit() != eCSSUnit_Null, "null value 3");
       value3.AppendToString(aProperties[2], aString, aSerialization);
       if (value2 != value4) {
         aString.Append(char16_t(' '));
         NS_ABORT_IF_FALSE(value4.GetUnit() != eCSSUnit_Null, "null value 4");
         value4.AppendToString(aProperties[3], aString, aSerialization);
       }
     }
   }
 }
 void
 Declaration::GetValue(nsCSSProperty aProperty, nsAString& aValue) const
 {
   GetValue(aProperty, aValue, nsCSSValue::eNormalized);
 }
 void
 Declaration::GetAuthoredValue(nsCSSProperty aProperty, nsAString& aValue) const
 {
   GetValue(aProperty, aValue, nsCSSValue::eAuthorSpecified);
 }
 void
 Declaration::GetValue(nsCSSProperty aProperty, nsAString& aValue,
                       nsCSSValue::Serialization aSerialization) const
 {
   aValue.Truncate(0);
   // simple properties are easy.
   if (!nsCSSProps::IsShorthand(aProperty)) {
     AppendValueToString(aProperty, aValue, aSerialization);
     return;
   }
   // DOM Level 2 Style says (when describing CSS2Properties, although
   // not CSSStyleDeclaration.getPropertyValue):
   //   However, if there is no shorthand declaration that could be added
   //   to the ruleset without changing in any way the rules already
   //   declared in the ruleset (i.e., by adding longhand rules that were
   //   previously not declared in the ruleset), then the empty string
   //   should be returned for the shorthand property.
   // This means we need to check a number of cases:
   //   (1) Since a shorthand sets all sub-properties, if some of its
   //       subproperties were not specified, we must return the empty
   //       string.
   //   (2) Since 'inherit', 'initial' and 'unset' can only be specified
   //       as the values for entire properties, we need to return the
   //       empty string if some but not all of the subproperties have one
   //       of those values.
   //   (3) Since a single value only makes sense with or without
   //       !important, we return the empty string if some values are
   //       !important and some are not.
   // Since we're doing this check for 'inherit' and 'initial' up front,
   // we can also simplify the property serialization code by serializing
   // those values up front as well.
   //
   // Additionally, if a shorthand property was set using a value with a
   // variable reference and none of its component longhand properties were
   // then overridden on the declaration, we return the token stream
   // assigned to the shorthand.
   const nsCSSValue* tokenStream = nullptr;
   uint32_t totalCount = 0, importantCount = 0,
            initialCount = 0, inheritCount = 0, unsetCount = 0,
            matchingTokenStreamCount = 0;
   CSSPROPS_FOR_SHORTHAND_SUBPROPERTIES(p, aProperty) {
     if (*p == eCSSProperty__x_system_font ||
          nsCSSProps::PropHasFlags(*p, CSS_PROPERTY_DIRECTIONAL_SOURCE)) {
       // The system-font subproperty and the *-source properties don't count.
       continue;
     }
     ++totalCount;
     const nsCSSValue *val = mData->ValueFor(*p);
     NS_ABORT_IF_FALSE(!val || !mImportantData || !mImportantData->ValueFor(*p),
                       "can't be in both blocks");
     if (!val && mImportantData) {
       ++importantCount;
       val = mImportantData->ValueFor(*p);
     }
     if (!val) {
       // Case (1) above: some subproperties not specified.
       return;
     }
     if (val->GetUnit() == eCSSUnit_Inherit) {
       ++inheritCount;
     } else if (val->GetUnit() == eCSSUnit_Initial) {
       ++initialCount;
     } else if (val->GetUnit() == eCSSUnit_Unset) {
       ++unsetCount;
     } else if (val->GetUnit() == eCSSUnit_TokenStream &&
                val->GetTokenStreamValue()->mShorthandPropertyID == aProperty) {
       tokenStream = val;
       ++matchingTokenStreamCount;
     }
   }
   if (importantCount != 0 && importantCount != totalCount) {
     // Case (3), no consistent importance.
     return;
   }
   if (initialCount == totalCount) {
     // Simplify serialization below by serializing initial up-front.
     nsCSSValue(eCSSUnit_Initial).AppendToString(eCSSProperty_UNKNOWN, aValue,
                                                 nsCSSValue::eNormalized);
     return;
   }
   if (inheritCount == totalCount) {
     // Simplify serialization below by serializing inherit up-front.
     nsCSSValue(eCSSUnit_Inherit).AppendToString(eCSSProperty_UNKNOWN, aValue,
                                                 nsCSSValue::eNormalized);
     return;
   }
   if (unsetCount == totalCount) {
     // Simplify serialization below by serializing unset up-front.
     nsCSSValue(eCSSUnit_Unset).AppendToString(eCSSProperty_UNKNOWN, aValue,
                                               nsCSSValue::eNormalized);
     return;
   }
   if (initialCount != 0 || inheritCount != 0 || unsetCount != 0) {
     // Case (2): partially initial, inherit or unset.
     return;
   }
   if (tokenStream) {
     if (matchingTokenStreamCount == totalCount) {
       // Shorthand was specified using variable references and all of its
       // longhand components were set by the shorthand.
       aValue.Append(tokenStream->GetTokenStreamValue()->mTokenStream);
     } else {
       // In all other cases, serialize to the empty string.
     }
     return;
   }
   nsCSSCompressedDataBlock *data = importantCount ? mImportantData : mData;
   switch (aProperty) {
     case eCSSProperty_margin:
     case eCSSProperty_padding:
     case eCSSProperty_border_color:
     case eCSSProperty_border_style:
     case eCSSProperty_border_width: {
       const nsCSSProperty* subprops =
         nsCSSProps::SubpropertyEntryFor(aProperty);
       NS_ABORT_IF_FALSE(nsCSSProps::GetStringValue(subprops[0]).Find("-top") !=
                         kNotFound, "first subprop must be top");
       NS_ABORT_IF_FALSE(nsCSSProps::GetStringValue(subprops[1]).Find("-right") !=
                         kNotFound, "second subprop must be right");
       NS_ABORT_IF_FALSE(nsCSSProps::GetStringValue(subprops[2]).Find("-bottom") !=
                         kNotFound, "third subprop must be bottom");
       NS_ABORT_IF_FALSE(nsCSSProps::GetStringValue(subprops[3]).Find("-left") !=
                         kNotFound, "fourth subprop must be left");
       const nsCSSValue* vals[4] = {
         data->ValueFor(subprops[0]),
         data->ValueFor(subprops[1]),
         data->ValueFor(subprops[2]),
         data->ValueFor(subprops[3])
       };
       AppendSidesShorthandToString(subprops, vals, aValue, aSerialization);
       break;
     }
     case eCSSProperty_border_radius:
     case eCSSProperty__moz_outline_radius: {
       const nsCSSProperty* subprops =
         nsCSSProps::SubpropertyEntryFor(aProperty);
       const nsCSSValue* vals[4] = {
         data->ValueFor(subprops[0]),
         data->ValueFor(subprops[1]),
         data->ValueFor(subprops[2]),
         data->ValueFor(subprops[3])
       };
       // For compatibility, only write a slash and the y-values
       // if they're not identical to the x-values.
       bool needY = false;
       const nsCSSValue* xVals[4];
       const nsCSSValue* yVals[4];
       for (int i = 0; i < 4; i++) {
         if (vals[i]->GetUnit() == eCSSUnit_Pair) {
           needY = true;
           xVals[i] = &vals[i]->GetPairValue().mXValue;
           yVals[i] = &vals[i]->GetPairValue().mYValue;
         } else {
           xVals[i] = yVals[i] = vals[i];
         }
       }
       AppendSidesShorthandToString(subprops, xVals, aValue, aSerialization);
       if (needY) {
         aValue.AppendLiteral(" / ");
         AppendSidesShorthandToString(subprops, yVals, aValue, aSerialization);
       }
       break;
     }
     case eCSSProperty_border_image: {
       // Even though there are some cases where we could omit
       // 'border-image-source' (when it's none), it's probably not a
       // good idea since it's likely to be confusing.  It would also
       // require adding the extra check that we serialize *something*.
       AppendValueToString(eCSSProperty_border_image_source, aValue,
                           aSerialization);
       bool sliceDefault = data->HasDefaultBorderImageSlice();
       bool widthDefault = data->HasDefaultBorderImageWidth();
       bool outsetDefault = data->HasDefaultBorderImageOutset();
       if (!sliceDefault || !widthDefault || !outsetDefault) {
         aValue.Append(char16_t(' '));
         AppendValueToString(eCSSProperty_border_image_slice, aValue,
                             aSerialization);
         if (!widthDefault || !outsetDefault) {
           aValue.Append(NS_LITERAL_STRING(" /"));
           if (!widthDefault) {
             aValue.Append(char16_t(' '));
             AppendValueToString(eCSSProperty_border_image_width, aValue,
                                 aSerialization);
           }
           if (!outsetDefault) {
             aValue.Append(NS_LITERAL_STRING(" / "));
             AppendValueToString(eCSSProperty_border_image_outset, aValue,
                                 aSerialization);
           }
         }
       }
       bool repeatDefault = data->HasDefaultBorderImageRepeat();
       if (!repeatDefault) {
         aValue.Append(char16_t(' '));
         AppendValueToString(eCSSProperty_border_image_repeat, aValue,
                             aSerialization);
       }
       break;
     }
     case eCSSProperty_border: {
       // If we have a non-default value for any of the properties that
       // this shorthand sets but cannot specify, we have to return the
       // empty string.
       if (data->ValueFor(eCSSProperty_border_image_source)->GetUnit() !=
             eCSSUnit_None ||
           !data->HasDefaultBorderImageSlice() ||
           !data->HasDefaultBorderImageWidth() ||
           !data->HasDefaultBorderImageOutset() ||
           !data->HasDefaultBorderImageRepeat() ||
           data->ValueFor(eCSSProperty_border_top_colors)->GetUnit() !=
             eCSSUnit_None ||
           data->ValueFor(eCSSProperty_border_right_colors)->GetUnit() !=
             eCSSUnit_None ||
           data->ValueFor(eCSSProperty_border_bottom_colors)->GetUnit() !=
             eCSSUnit_None ||
           data->ValueFor(eCSSProperty_border_left_colors)->GetUnit() !=
             eCSSUnit_None) {
         break;
       }
       const nsCSSProperty* subproptables[3] = {
         nsCSSProps::SubpropertyEntryFor(eCSSProperty_border_color),
         nsCSSProps::SubpropertyEntryFor(eCSSProperty_border_style),
         nsCSSProps::SubpropertyEntryFor(eCSSProperty_border_width)
       };
       bool match = true;
       for (const nsCSSProperty** subprops = subproptables,
                **subprops_end = ArrayEnd(subproptables);
            subprops < subprops_end; ++subprops) {
         // Check only the first four subprops in each table, since the
         // others are extras for dimensional box properties.
         const nsCSSValue *firstSide = data->ValueFor((*subprops)[0]);
         for (int32_t side = 1; side < 4; ++side) {
           const nsCSSValue *otherSide =
             data->ValueFor((*subprops)[side]);
           if (*firstSide != *otherSide)
             match = false;
         }
       }
       if (!match) {
         // We can't express what we have in the border shorthand
         break;
       }
       // tweak aProperty and fall through
       aProperty = eCSSProperty_border_top;
     }
     case eCSSProperty_border_top:
     case eCSSProperty_border_right:
     case eCSSProperty_border_bottom:
     case eCSSProperty_border_left:
     case eCSSProperty_border_start:
     case eCSSProperty_border_end:
     case eCSSProperty__moz_column_rule:
     case eCSSProperty_outline: {
       const nsCSSProperty* subprops =
         nsCSSProps::SubpropertyEntryFor(aProperty);
       NS_ABORT_IF_FALSE(StringEndsWith(nsCSSProps::GetStringValue(subprops[2]),
                                        NS_LITERAL_CSTRING("-color")) ||
                         StringEndsWith(nsCSSProps::GetStringValue(subprops[2]),
                                        NS_LITERAL_CSTRING("-color-value")),
                         "third subprop must be the color property");
       const nsCSSValue *colorValue = data->ValueFor(subprops[2]);
       bool isMozUseTextColor =
         colorValue->GetUnit() == eCSSUnit_Enumerated &&
         colorValue->GetIntValue() == NS_STYLE_COLOR_MOZ_USE_TEXT_COLOR;
       if (!AppendValueToString(subprops[0], aValue, aSerialization) ||
           !(aValue.Append(char16_t(' ')),
             AppendValueToString(subprops[1], aValue, aSerialization)) ||
           // Don't output a third value when it's -moz-use-text-color.
           !(isMozUseTextColor ||
             (aValue.Append(char16_t(' ')),
              AppendValueToString(subprops[2], aValue, aSerialization)))) {
         aValue.Truncate();
       }
       break;
     }
     case eCSSProperty_margin_left:
     case eCSSProperty_margin_right:
     case eCSSProperty_margin_start:
     case eCSSProperty_margin_end:
     case eCSSProperty_padding_left:
     case eCSSProperty_padding_right:
     case eCSSProperty_padding_start:
     case eCSSProperty_padding_end:
     case eCSSProperty_border_left_color:
     case eCSSProperty_border_left_style:
     case eCSSProperty_border_left_width:
     case eCSSProperty_border_right_color:
     case eCSSProperty_border_right_style:
     case eCSSProperty_border_right_width:
     case eCSSProperty_border_start_color:
     case eCSSProperty_border_start_style:
     case eCSSProperty_border_start_width:
     case eCSSProperty_border_end_color:
     case eCSSProperty_border_end_style:
     case eCSSProperty_border_end_width: {
       const nsCSSProperty* subprops =
         nsCSSProps::SubpropertyEntryFor(aProperty);
       NS_ABORT_IF_FALSE(subprops[3] == eCSSProperty_UNKNOWN,
                         "not box property with physical vs. logical cascading");
       AppendValueToString(subprops[0], aValue, aSerialization);
       break;
     }
     case eCSSProperty_background: {
       // We know from above that all subproperties were specified.
       // However, we still can't represent that in the shorthand unless
       // they're all lists of the same length.  So if they're different
       // lengths, we need to bail out.
       // We also need to bail out if an item has background-clip and
       // background-origin that are different and not the default
       // values.  (We omit them if they're both default.)
       const nsCSSValueList *image =
         data->ValueFor(eCSSProperty_background_image)->
         GetListValue();
       const nsCSSValuePairList *repeat =
         data->ValueFor(eCSSProperty_background_repeat)->
         GetPairListValue();
       const nsCSSValueList *attachment =
         data->ValueFor(eCSSProperty_background_attachment)->
         GetListValue();
       const nsCSSValueList *position =
         data->ValueFor(eCSSProperty_background_position)->
         GetListValue();
       const nsCSSValueList *clip =
         data->ValueFor(eCSSProperty_background_clip)->
         GetListValue();
       const nsCSSValueList *origin =
         data->ValueFor(eCSSProperty_background_origin)->
         GetListValue();
       const nsCSSValuePairList *size =
         data->ValueFor(eCSSProperty_background_size)->
         GetPairListValue();
       for (;;) {
         image->mValue.AppendToString(eCSSProperty_background_image, aValue,
                                      aSerialization);
         aValue.Append(char16_t(' '));
         repeat->mXValue.AppendToString(eCSSProperty_background_repeat, aValue,
                                        aSerialization);
         if (repeat->mYValue.GetUnit() != eCSSUnit_Null) {
           repeat->mYValue.AppendToString(eCSSProperty_background_repeat, aValue,
                                          aSerialization);
         }
         aValue.Append(char16_t(' '));
         attachment->mValue.AppendToString(eCSSProperty_background_attachment,
                                           aValue, aSerialization);
         aValue.Append(char16_t(' '));
         position->mValue.AppendToString(eCSSProperty_background_position,
                                         aValue, aSerialization);
         if (size->mXValue.GetUnit() != eCSSUnit_Auto ||
             size->mYValue.GetUnit() != eCSSUnit_Auto) {
           aValue.Append(char16_t(' '));
           aValue.Append(char16_t('/'));
           aValue.Append(char16_t(' '));
           size->mXValue.AppendToString(eCSSProperty_background_size, aValue,
                                        aSerialization);
           aValue.Append(char16_t(' '));
           size->mYValue.AppendToString(eCSSProperty_background_size, aValue,
                                        aSerialization);
         }
         NS_ABORT_IF_FALSE(clip->mValue.GetUnit() == eCSSUnit_Enumerated &&
                           origin->mValue.GetUnit() == eCSSUnit_Enumerated,
                           "should not have inherit/initial within list");
         if (clip->mValue.GetIntValue() != NS_STYLE_BG_CLIP_BORDER ||
             origin->mValue.GetIntValue() != NS_STYLE_BG_ORIGIN_PADDING) {
           MOZ_ASSERT(nsCSSProps::kKeywordTableTable[
                        eCSSProperty_background_origin] ==
                      nsCSSProps::kBackgroundOriginKTable);
           MOZ_ASSERT(nsCSSProps::kKeywordTableTable[
                        eCSSProperty_background_clip] ==
                      nsCSSProps::kBackgroundOriginKTable);
           static_assert(NS_STYLE_BG_CLIP_BORDER ==
                         NS_STYLE_BG_ORIGIN_BORDER &&
                         NS_STYLE_BG_CLIP_PADDING ==
                         NS_STYLE_BG_ORIGIN_PADDING &&
                         NS_STYLE_BG_CLIP_CONTENT ==
                         NS_STYLE_BG_ORIGIN_CONTENT,
                         "bg-clip and bg-origin style constants must agree");
           aValue.Append(char16_t(' '));
           origin->mValue.AppendToString(eCSSProperty_background_origin, aValue,
                                         aSerialization);
           if (clip->mValue != origin->mValue) {
             aValue.Append(char16_t(' '));
             clip->mValue.AppendToString(eCSSProperty_background_clip, aValue,
                                         aSerialization);
           }
         }
         image = image->mNext;
         repeat = repeat->mNext;
         attachment = attachment->mNext;
         position = position->mNext;
         clip = clip->mNext;
         origin = origin->mNext;
         size = size->mNext;
         if (!image) {
           if (repeat || attachment || position || clip || origin || size) {
             // Uneven length lists, so can't be serialized as shorthand.
             aValue.Truncate();
             return;
           }
           break;
         }
         if (!repeat || !attachment || !position || !clip || !origin || !size) {
           // Uneven length lists, so can't be serialized as shorthand.
           aValue.Truncate();
           return;
         }
         aValue.Append(char16_t(','));
         aValue.Append(char16_t(' '));
       }
       aValue.Append(char16_t(' '));
       AppendValueToString(eCSSProperty_background_color, aValue,
                           aSerialization);
       break;
     }
     case eCSSProperty_font: {
       // systemFont might not be present; other values are guaranteed to be
       // available based on the shorthand check at the beginning of the
       // function, as long as the prop is enabled
       const nsCSSValue *systemFont =
         data->ValueFor(eCSSProperty__x_system_font);
       const nsCSSValue *style =
         data->ValueFor(eCSSProperty_font_style);
       const nsCSSValue *variant =
         data->ValueFor(eCSSProperty_font_variant);
       const nsCSSValue *weight =
         data->ValueFor(eCSSProperty_font_weight);
       const nsCSSValue *size =
         data->ValueFor(eCSSProperty_font_size);
       const nsCSSValue *lh =
         data->ValueFor(eCSSProperty_line_height);
       const nsCSSValue *family =
         data->ValueFor(eCSSProperty_font_family);
       const nsCSSValue *stretch =
         data->ValueFor(eCSSProperty_font_stretch);
       const nsCSSValue *sizeAdjust =
         data->ValueFor(eCSSProperty_font_size_adjust);
       const nsCSSValue *featureSettings =
         data->ValueFor(eCSSProperty_font_feature_settings);
       const nsCSSValue *languageOverride =
         data->ValueFor(eCSSProperty_font_language_override);
       const nsCSSValue *fontKerning =
         data->ValueFor(eCSSProperty_font_kerning);
       const nsCSSValue *fontSynthesis =
         data->ValueFor(eCSSProperty_font_synthesis);
       const nsCSSValue *fontVariantAlternates =
         data->ValueFor(eCSSProperty_font_variant_alternates);
       const nsCSSValue *fontVariantCaps =
         data->ValueFor(eCSSProperty_font_variant_caps);
       const nsCSSValue *fontVariantEastAsian =
         data->ValueFor(eCSSProperty_font_variant_east_asian);
       const nsCSSValue *fontVariantLigatures =
         data->ValueFor(eCSSProperty_font_variant_ligatures);
       const nsCSSValue *fontVariantNumeric =
         data->ValueFor(eCSSProperty_font_variant_numeric);
       const nsCSSValue *fontVariantPosition =
         data->ValueFor(eCSSProperty_font_variant_position);
       // if font features are not enabled, pointers for fontVariant
       // values above may be null since the shorthand check ignores them
       // font-variant-alternates enabled ==> layout.css.font-features.enabled is true
       bool fontFeaturesEnabled =
         nsCSSProps::IsEnabled(eCSSProperty_font_variant_alternates);
       if (systemFont &&
           systemFont->GetUnit() != eCSSUnit_None &&
           systemFont->GetUnit() != eCSSUnit_Null) {
         if (style->GetUnit() != eCSSUnit_System_Font ||
             variant->GetUnit() != eCSSUnit_System_Font ||
             weight->GetUnit() != eCSSUnit_System_Font ||
             size->GetUnit() != eCSSUnit_System_Font ||
             lh->GetUnit() != eCSSUnit_System_Font ||
             family->GetUnit() != eCSSUnit_System_Font ||
             stretch->GetUnit() != eCSSUnit_System_Font ||
             sizeAdjust->GetUnit() != eCSSUnit_System_Font ||
             featureSettings->GetUnit() != eCSSUnit_System_Font ||
             languageOverride->GetUnit() != eCSSUnit_System_Font ||
             (fontFeaturesEnabled &&
              (fontKerning->GetUnit() != eCSSUnit_System_Font ||
               fontSynthesis->GetUnit() != eCSSUnit_System_Font ||
               fontVariantAlternates->GetUnit() != eCSSUnit_System_Font ||
               fontVariantCaps->GetUnit() != eCSSUnit_System_Font ||
               fontVariantEastAsian->GetUnit() != eCSSUnit_System_Font ||
               fontVariantLigatures->GetUnit() != eCSSUnit_System_Font ||
               fontVariantNumeric->GetUnit() != eCSSUnit_System_Font ||
               fontVariantPosition->GetUnit() != eCSSUnit_System_Font))) {
           // This can't be represented as a shorthand.
           return;
         }
         systemFont->AppendToString(eCSSProperty__x_system_font, aValue,
                                    aSerialization);
       } else {
         // properties reset by this shorthand property to their
         // initial values but not represented in its syntax
         if (stretch->GetUnit() != eCSSUnit_Enumerated ||
             stretch->GetIntValue() != NS_STYLE_FONT_STRETCH_NORMAL ||
             sizeAdjust->GetUnit() != eCSSUnit_None ||
             featureSettings->GetUnit() != eCSSUnit_Normal ||
             languageOverride->GetUnit() != eCSSUnit_Normal ||
             (fontFeaturesEnabled &&
              (fontKerning->GetIntValue() != NS_FONT_KERNING_AUTO ||
               fontSynthesis->GetUnit() != eCSSUnit_Enumerated ||
               fontSynthesis->GetIntValue() !=
                 (NS_FONT_SYNTHESIS_WEIGHT | NS_FONT_SYNTHESIS_STYLE) ||
               fontVariantAlternates->GetUnit() != eCSSUnit_Normal ||
               fontVariantCaps->GetUnit() != eCSSUnit_Normal ||
               fontVariantEastAsian->GetUnit() != eCSSUnit_Normal ||
               fontVariantLigatures->GetUnit() != eCSSUnit_Normal ||
               fontVariantNumeric->GetUnit() != eCSSUnit_Normal ||
               fontVariantPosition->GetUnit() != eCSSUnit_Normal))) {
           return;
         }
         if (style->GetUnit() != eCSSUnit_Enumerated ||
             style->GetIntValue() != NS_FONT_STYLE_NORMAL) {
           style->AppendToString(eCSSProperty_font_style, aValue,
                                 aSerialization);
           aValue.Append(char16_t(' '));
         }
         if (variant->GetUnit() != eCSSUnit_Enumerated ||
             variant->GetIntValue() != NS_FONT_VARIANT_NORMAL) {
           variant->AppendToString(eCSSProperty_font_variant, aValue,
                                   aSerialization);
           aValue.Append(char16_t(' '));
         }
         if (weight->GetUnit() != eCSSUnit_Enumerated ||
             weight->GetIntValue() != NS_FONT_WEIGHT_NORMAL) {
           weight->AppendToString(eCSSProperty_font_weight, aValue,
                                  aSerialization);
           aValue.Append(char16_t(' '));
         }
         size->AppendToString(eCSSProperty_font_size, aValue, aSerialization);
         if (lh->GetUnit() != eCSSUnit_Normal) {
           aValue.Append(char16_t('/'));
           lh->AppendToString(eCSSProperty_line_height, aValue, aSerialization);
         }
         aValue.Append(char16_t(' '));
         family->AppendToString(eCSSProperty_font_family, aValue,
                                aSerialization);
       }
       break;
     }
     case eCSSProperty_list_style:
       if (AppendValueToString(eCSSProperty_list_style_type, aValue,
                               aSerialization)) {
         aValue.Append(char16_t(' '));
       }
       if (AppendValueToString(eCSSProperty_list_style_position, aValue,
                               aSerialization)) {
         aValue.Append(char16_t(' '));
       }
       AppendValueToString(eCSSProperty_list_style_image, aValue,
                           aSerialization);
       break;
     case eCSSProperty_overflow: {
       const nsCSSValue &xValue =
         *data->ValueFor(eCSSProperty_overflow_x);
       const nsCSSValue &yValue =
         *data->ValueFor(eCSSProperty_overflow_y);
       if (xValue == yValue)
         xValue.AppendToString(eCSSProperty_overflow_x, aValue, aSerialization);
       break;
     }
     case eCSSProperty_text_decoration: {
       // If text-decoration-color or text-decoration-style isn't initial value,
       // we cannot serialize the text-decoration shorthand value.
       const nsCSSValue *decorationColor =
         data->ValueFor(eCSSProperty_text_decoration_color);
       const nsCSSValue *decorationStyle =
         data->ValueFor(eCSSProperty_text_decoration_style);
       NS_ABORT_IF_FALSE(decorationStyle->GetUnit() == eCSSUnit_Enumerated,
                         nsPrintfCString("bad text-decoration-style unit %d",
                                         decorationStyle->GetUnit()).get());
       if (decorationColor->GetUnit() != eCSSUnit_Enumerated ||
           decorationColor->GetIntValue() != NS_STYLE_COLOR_MOZ_USE_TEXT_COLOR ||
           decorationStyle->GetIntValue() !=
             NS_STYLE_TEXT_DECORATION_STYLE_SOLID) {
         return;
       }
       AppendValueToString(eCSSProperty_text_decoration_line, aValue,
                           aSerialization);
       break;
     }
     case eCSSProperty_transition: {
       const nsCSSValue *transProp =
         data->ValueFor(eCSSProperty_transition_property);
       const nsCSSValue *transDuration =
         data->ValueFor(eCSSProperty_transition_duration);
       const nsCSSValue *transTiming =
         data->ValueFor(eCSSProperty_transition_timing_function);
       const nsCSSValue *transDelay =
         data->ValueFor(eCSSProperty_transition_delay);
       NS_ABORT_IF_FALSE(transDuration->GetUnit() == eCSSUnit_List ||
                         transDuration->GetUnit() == eCSSUnit_ListDep,
                         nsPrintfCString("bad t-duration unit %d",
                                         transDuration->GetUnit()).get());
       NS_ABORT_IF_FALSE(transTiming->GetUnit() == eCSSUnit_List ||
                         transTiming->GetUnit() == eCSSUnit_ListDep,
                         nsPrintfCString("bad t-timing unit %d",
                                         transTiming->GetUnit()).get());
       NS_ABORT_IF_FALSE(transDelay->GetUnit() == eCSSUnit_List ||
                         transDelay->GetUnit() == eCSSUnit_ListDep,
                         nsPrintfCString("bad t-delay unit %d",
                                         transDelay->GetUnit()).get());
       const nsCSSValueList* dur = transDuration->GetListValue();
       const nsCSSValueList* tim = transTiming->GetListValue();
       const nsCSSValueList* del = transDelay->GetListValue();
       if (transProp->GetUnit() == eCSSUnit_None ||
           transProp->GetUnit() == eCSSUnit_All) {
         // If any of the other three lists has more than one element,
         // we can't use the shorthand.
         if (!dur->mNext && !tim->mNext && !del->mNext) {
           transProp->AppendToString(eCSSProperty_transition_property, aValue,
                                     aSerialization);
           aValue.Append(char16_t(' '));
           dur->mValue.AppendToString(eCSSProperty_transition_duration,aValue,
                                      aSerialization);
           aValue.Append(char16_t(' '));
           tim->mValue.AppendToString(eCSSProperty_transition_timing_function,
                                      aValue, aSerialization);
           aValue.Append(char16_t(' '));
           del->mValue.AppendToString(eCSSProperty_transition_delay, aValue,
                                      aSerialization);
           aValue.Append(char16_t(' '));
         } else {
           aValue.Truncate();
         }
       } else {
         NS_ABORT_IF_FALSE(transProp->GetUnit() == eCSSUnit_List ||
                           transProp->GetUnit() == eCSSUnit_ListDep,
                           nsPrintfCString("bad t-prop unit %d",
                                           transProp->GetUnit()).get());
         const nsCSSValueList* pro = transProp->GetListValue();
         for (;;) {
           pro->mValue.AppendToString(eCSSProperty_transition_property,
                                         aValue, aSerialization);
           aValue.Append(char16_t(' '));
           dur->mValue.AppendToString(eCSSProperty_transition_duration,
                                         aValue, aSerialization);
           aValue.Append(char16_t(' '));
           tim->mValue.AppendToString(eCSSProperty_transition_timing_function,
                                         aValue, aSerialization);
           aValue.Append(char16_t(' '));
           del->mValue.AppendToString(eCSSProperty_transition_delay,
                                         aValue, aSerialization);
           pro = pro->mNext;
           dur = dur->mNext;
           tim = tim->mNext;
           del = del->mNext;
           if (!pro || !dur || !tim || !del) {
             break;
           }
           aValue.AppendLiteral(", ");
         }
         if (pro || dur || tim || del) {
           // Lists not all the same length, can't use shorthand.
           aValue.Truncate();
         }
       }
       break;
     }
     case eCSSProperty_animation: {
       const nsCSSProperty* subprops =
         nsCSSProps::SubpropertyEntryFor(eCSSProperty_animation);
       static const size_t numProps = 7;
       NS_ABORT_IF_FALSE(subprops[numProps] == eCSSProperty_UNKNOWN,
                         "unexpected number of subproperties");
       const nsCSSValue* values[numProps];
       const nsCSSValueList* lists[numProps];
       for (uint32_t i = 0; i < numProps; ++i) {
         values[i] = data->ValueFor(subprops[i]);
         NS_ABORT_IF_FALSE(values[i]->GetUnit() == eCSSUnit_List ||
                           values[i]->GetUnit() == eCSSUnit_ListDep,
                           nsPrintfCString("bad a-duration unit %d",
                                           values[i]->GetUnit()).get());
         lists[i] = values[i]->GetListValue();
       }
       for (;;) {
         // We must serialize 'animation-name' last in case it has
         // a value that conflicts with one of the other keyword properties.
         NS_ABORT_IF_FALSE(subprops[numProps - 1] ==
                             eCSSProperty_animation_name,
                           "animation-name must be last");
         bool done = false;
         for (uint32_t i = 0;;) {
           lists[i]->mValue.AppendToString(subprops[i], aValue, aSerialization);
           lists[i] = lists[i]->mNext;
           if (!lists[i]) {
             done = true;
           }
           if (++i == numProps) {
             break;
           }
           aValue.Append(char16_t(' '));
         }
         if (done) {
           break;
         }
         aValue.AppendLiteral(", ");
       }
       for (uint32_t i = 0; i < numProps; ++i) {
         if (lists[i]) {
           // Lists not all the same length, can't use shorthand.
           aValue.Truncate();
           break;
         }
       }
       break;
     }
     case eCSSProperty_marker: {
       const nsCSSValue &endValue =
         *data->ValueFor(eCSSProperty_marker_end);
       const nsCSSValue &midValue =
         *data->ValueFor(eCSSProperty_marker_mid);
       const nsCSSValue &startValue =
         *data->ValueFor(eCSSProperty_marker_start);
       if (endValue == midValue && midValue == startValue)
         AppendValueToString(eCSSProperty_marker_end, aValue, aSerialization);
       break;
     }
     case eCSSProperty__moz_columns: {
       // Two values, column-count and column-width, separated by a space.
       const nsCSSProperty* subprops =
         nsCSSProps::SubpropertyEntryFor(aProperty);
       AppendValueToString(subprops[0], aValue, aSerialization);
       aValue.Append(char16_t(' '));
       AppendValueToString(subprops[1], aValue, aSerialization);
       break;
     }
     case eCSSProperty_flex: {
       // flex-grow, flex-shrink, flex-basis, separated by single space
       const nsCSSProperty* subprops =
         nsCSSProps::SubpropertyEntryFor(aProperty);
       AppendValueToString(subprops[0], aValue, aSerialization);
       aValue.Append(char16_t(' '));
       AppendValueToString(subprops[1], aValue, aSerialization);
       aValue.Append(char16_t(' '));
       AppendValueToString(subprops[2], aValue, aSerialization);
       break;
     }
     case eCSSProperty_flex_flow: {
       // flex-direction, flex-wrap, separated by single space
       const nsCSSProperty* subprops =
         nsCSSProps::SubpropertyEntryFor(aProperty);
       NS_ABORT_IF_FALSE(subprops[2] == eCSSProperty_UNKNOWN,
                         "must have exactly two subproperties");
       AppendValueToString(subprops[0], aValue, aSerialization);
       aValue.Append(char16_t(' '));
       AppendValueToString(subprops[1], aValue, aSerialization);
       break;
     }
     case eCSSProperty_grid_row:
     case eCSSProperty_grid_column: {
       // grid-{row,column}-start, grid-{row,column}-end, separated by a slash
       const nsCSSProperty* subprops =
         nsCSSProps::SubpropertyEntryFor(aProperty);
       NS_ABORT_IF_FALSE(subprops[2] == eCSSProperty_UNKNOWN,
                         "must have exactly two subproperties");
       // TODO: should we simplify when possible?
       AppendValueToString(subprops[0], aValue, aSerialization);
       aValue.AppendLiteral(" / ");
       AppendValueToString(subprops[1], aValue, aSerialization);
       break;
     }
     case eCSSProperty_grid_area: {
       const nsCSSProperty* subprops =
         nsCSSProps::SubpropertyEntryFor(aProperty);
       NS_ABORT_IF_FALSE(subprops[4] == eCSSProperty_UNKNOWN,
                         "must have exactly four subproperties");
       // TODO: should we simplify when possible?
       AppendValueToString(subprops[0], aValue, aSerialization);
       aValue.AppendLiteral(" / ");
       AppendValueToString(subprops[1], aValue, aSerialization);
       aValue.AppendLiteral(" / ");
       AppendValueToString(subprops[2], aValue, aSerialization);
       aValue.AppendLiteral(" / ");
       AppendValueToString(subprops[3], aValue, aSerialization);
       break;
     }
     // This can express either grid-template-{areas,columns,rows}
     // or grid-auto-{flow,columns,rows}, but not both.
     case eCSSProperty_grid: {
       const nsCSSValue& areasValue =
         *data->ValueFor(eCSSProperty_grid_template_areas);
       const nsCSSValue& columnsValue =
         *data->ValueFor(eCSSProperty_grid_template_columns);
       const nsCSSValue& rowsValue =
         *data->ValueFor(eCSSProperty_grid_template_rows);
       const nsCSSValue& autoFlowValue =
         *data->ValueFor(eCSSProperty_grid_auto_flow);
       const nsCSSValue& autoColumnsValue =
         *data->ValueFor(eCSSProperty_grid_auto_columns);
       const nsCSSValue& autoRowsValue =
         *data->ValueFor(eCSSProperty_grid_auto_rows);
       if (areasValue.GetUnit() == eCSSUnit_None &&
           columnsValue.GetUnit() == eCSSUnit_None &&
           rowsValue.GetUnit() == eCSSUnit_None) {
         AppendValueToString(eCSSProperty_grid_auto_flow,
                             aValue, aSerialization);
         aValue.Append(char16_t(' '));
         AppendValueToString(eCSSProperty_grid_auto_columns,
                             aValue, aSerialization);
         aValue.AppendLiteral(" / ");
         AppendValueToString(eCSSProperty_grid_auto_rows,
                             aValue, aSerialization);
         break;
       } else if (!(autoFlowValue.GetUnit() == eCSSUnit_Enumerated &&
                    autoFlowValue.GetIntValue() == NS_STYLE_GRID_AUTO_FLOW_NONE &&
                    autoColumnsValue.GetUnit() == eCSSUnit_Auto &&
                    autoRowsValue.GetUnit() == eCSSUnit_Auto)) {
         // Not serializable, bail.
         return;
       }
       // Fall through to eCSSProperty_grid_template
     }
     case eCSSProperty_grid_template: {
       const nsCSSValue& areasValue =
         *data->ValueFor(eCSSProperty_grid_template_areas);
       const nsCSSValue& columnsValue =
         *data->ValueFor(eCSSProperty_grid_template_columns);
       const nsCSSValue& rowsValue =
         *data->ValueFor(eCSSProperty_grid_template_rows);
       if (areasValue.GetUnit() == eCSSUnit_None) {
         AppendValueToString(eCSSProperty_grid_template_columns,
                             aValue, aSerialization);
         aValue.AppendLiteral(" / ");
         AppendValueToString(eCSSProperty_grid_template_rows,
                             aValue, aSerialization);
         break;
       }
       if (columnsValue.GetUnit() == eCSSUnit_List ||
           columnsValue.GetUnit() == eCSSUnit_ListDep) {
         const nsCSSValueList* columnsItem = columnsValue.GetListValue();
         if (columnsItem->mValue.GetUnit() == eCSSUnit_Enumerated &&
             columnsItem->mValue.GetIntValue() == NS_STYLE_GRID_TEMPLATE_SUBGRID) {
           // We have "grid-template-areas:[something]; grid-template-columns:subgrid"
           // which isn't a value that the shorthand can express. Bail.
           return;
         }
       }
       if (rowsValue.GetUnit() != eCSSUnit_List &&
           rowsValue.GetUnit() != eCSSUnit_ListDep) {
         // We have "grid-template-areas:[something]; grid-template-rows:none"
         // which isn't a value that the shorthand can express. Bail.
         return;
       }
       const nsCSSValueList* rowsItem = rowsValue.GetListValue();
       if (rowsItem->mValue.GetUnit() == eCSSUnit_Enumerated &&
           rowsItem->mValue.GetIntValue() == NS_STYLE_GRID_TEMPLATE_SUBGRID) {
         // We have "grid-template-areas:[something]; grid-template-rows:subgrid"
         // which isn't a value that the shorthand can express. Bail.
         return;
       }
       const GridTemplateAreasValue* areas = areasValue.GetGridTemplateAreas();
       uint32_t nRowItems = 0;
       while (rowsItem) {
         nRowItems++;
         rowsItem = rowsItem->mNext;
       }
       MOZ_ASSERT(nRowItems % 2 == 1, "expected an odd number of items");
       if ((nRowItems - 1) / 2 != areas->NRows()) {
         // Not serializable, bail.
         return;
       }
       if (columnsValue.GetUnit() != eCSSUnit_None) {
         AppendValueToString(eCSSProperty_grid_template_columns,
                             aValue, aSerialization);
         aValue.AppendLiteral(" / ");
       }
       rowsItem = rowsValue.GetListValue();
       uint32_t row = 0;
       for (;;) {
         bool addSpaceSeparator = true;
         nsCSSUnit unit = rowsItem->mValue.GetUnit();
         if (unit == eCSSUnit_Null) {
           // Empty or omitted <line-names>. Serializes to nothing.
           addSpaceSeparator = false;  // Avoid a double space.
         } else if (unit == eCSSUnit_List || unit == eCSSUnit_ListDep) {
           // Non-empty <line-names>
           aValue.AppendLiteral("(");
           rowsItem->mValue.AppendToString(eCSSProperty_grid_template_rows,
                                           aValue, aSerialization);
           aValue.AppendLiteral(")");
         } else {
           nsStyleUtil::AppendEscapedCSSString(areas->mTemplates[row++], aValue);
           aValue.Append(char16_t(' '));
           // <track-size>
           rowsItem->mValue.AppendToString(eCSSProperty_grid_template_rows,
                                           aValue, aSerialization);
           if (rowsItem->mNext &&
               rowsItem->mNext->mValue.GetUnit() == eCSSUnit_Null &&
               !rowsItem->mNext->mNext) {
             // Break out of the loop early to avoid a trailing space.
             break;
           }
         }
         rowsItem = rowsItem->mNext;
         if (!rowsItem) {
           break;
         }
         if (addSpaceSeparator) {
           aValue.Append(char16_t(' '));
         }
       }
       break;
     }
     case eCSSProperty__moz_transform: {
       // shorthands that are just aliases with different parsing rules
       const nsCSSProperty* subprops =
         nsCSSProps::SubpropertyEntryFor(aProperty);
       NS_ABORT_IF_FALSE(subprops[1] == eCSSProperty_UNKNOWN,
                         "must have exactly one subproperty");
       AppendValueToString(subprops[0], aValue, aSerialization);
       break;
     }
     case eCSSProperty_all:
       // If we got here, then we didn't have all "inherit" or "initial" or
       // "unset" values for all of the longhand property components of 'all'.
       // There is no other possible value that is valid for all properties,
       // so serialize as the empty string.
       break;
     default:
       NS_ABORT_IF_FALSE(false, "no other shorthands");
       break;
   }
 }
 bool
 Declaration::GetValueIsImportant(const nsAString& aProperty) const
 {
   nsCSSProperty propID =
     nsCSSProps::LookupProperty(aProperty, nsCSSProps::eIgnoreEnabledState);
   if (propID == eCSSProperty_UNKNOWN) {
     return false;
   }
   if (propID == eCSSPropertyExtra_variable) {
     const nsSubstring& variableName =
       Substring(aProperty, CSS_CUSTOM_NAME_PREFIX_LENGTH);
     return GetVariableValueIsImportant(variableName);
   }
   return GetValueIsImportant(propID);
 }
 bool
 Declaration::GetValueIsImportant(nsCSSProperty aProperty) const
 {
   if (!mImportantData)
     return false;
   // Calling ValueFor is inefficient, but we can assume '!important' is rare.
   if (!nsCSSProps::IsShorthand(aProperty)) {
     return mImportantData->ValueFor(aProperty) != nullptr;
   }
   CSSPROPS_FOR_SHORTHAND_SUBPROPERTIES(p, aProperty) {
     if (*p == eCSSProperty__x_system_font) {
       // The system_font subproperty doesn't count.
       continue;
     }
     if (!mImportantData->ValueFor(*p)) {
       return false;
     }
   }
   return true;
 }
 void
 Declaration::AppendPropertyAndValueToString(nsCSSProperty aProperty,
                                             nsAutoString& aValue,
                                             nsAString& aResult) const
 {
   NS_ABORT_IF_FALSE(0 <= aProperty && aProperty < eCSSProperty_COUNT,
                     "property enum out of range");
   NS_ABORT_IF_FALSE((aProperty < eCSSProperty_COUNT_no_shorthands) ==
                     aValue.IsEmpty(),
                     "aValue should be given for shorthands but not longhands");
   AppendASCIItoUTF16(nsCSSProps::GetStringValue(aProperty), aResult);
   aResult.AppendLiteral(": ");
   if (aValue.IsEmpty())
     AppendValueToString(aProperty, aResult, nsCSSValue::eNormalized);
   else
     aResult.Append(aValue);
   if (GetValueIsImportant(aProperty)) {
     aResult.AppendLiteral(" ! important");
   }
   aResult.AppendLiteral("; ");
 }
 void
 Declaration::AppendVariableAndValueToString(const nsAString& aName,
                                             nsAString& aResult) const
 {
   aResult.AppendLiteral("--");
   aResult.Append(aName);
   CSSVariableDeclarations::Type type;
   nsString value;
   bool important;
   if (mImportantVariables && mImportantVariables->Get(aName, type, value)) {
     important = true;
   } else {
     MOZ_ASSERT(mVariables);
     MOZ_ASSERT(mVariables->Has(aName));
     mVariables->Get(aName, type, value);
     important = false;
   }
   switch (type) {
     case CSSVariableDeclarations::eTokenStream:
       if (value.IsEmpty()) {
         aResult.Append(':');
       } else {
         aResult.AppendLiteral(": ");
         aResult.Append(value);
       }
       break;
     case CSSVariableDeclarations::eInitial:
       aResult.AppendLiteral("initial");
       break;
     case CSSVariableDeclarations::eInherit:
       aResult.AppendLiteral("inherit");
       break;
     case CSSVariableDeclarations::eUnset:
       aResult.AppendLiteral("unset");
       break;
     default:
       MOZ_ASSERT(false, "unexpected variable value type");
   }
   if (important) {
     aResult.AppendLiteral("! important");
   }
   aResult.AppendLiteral("; ");
 }
 void
 Declaration::ToString(nsAString& aString) const
 {
   // Someone cares about this declaration's contents, so don't let it
   // change from under them.  See e.g. bug 338679.
   SetImmutable();
   nsCSSCompressedDataBlock *systemFontData =
     GetValueIsImportant(eCSSProperty__x_system_font) ? mImportantData : mData;
   const nsCSSValue *systemFont =
     systemFontData->ValueFor(eCSSProperty__x_system_font);
   const bool haveSystemFont = systemFont &&
                                 systemFont->GetUnit() != eCSSUnit_None &&
                                 systemFont->GetUnit() != eCSSUnit_Null;
   bool didSystemFont = false;
   int32_t count = mOrder.Length();
   int32_t index;
   nsAutoTArray<nsCSSProperty, 16> shorthandsUsed;
   for (index = 0; index < count; index++) {
     nsCSSProperty property = GetPropertyAt(index);
     if (property == eCSSPropertyExtra_variable) {
       uint32_t variableIndex = mOrder[index] - eCSSProperty_COUNT;
       AppendVariableAndValueToString(mVariableOrder[variableIndex], aString);
       continue;
     }
     if (!nsCSSProps::IsEnabled(property)) {
       continue;
     }
     bool doneProperty = false;
     // If we already used this property in a shorthand, skip it.
     if (shorthandsUsed.Length() > 0) {
       for (const nsCSSProperty *shorthands =
              nsCSSProps::ShorthandsContaining(property);
            *shorthands != eCSSProperty_UNKNOWN; ++shorthands) {
         if (shorthandsUsed.Contains(*shorthands)) {
           doneProperty = true;
           break;
         }
       }
       if (doneProperty)
         continue;
     }
     // Try to use this property in a shorthand.
     nsAutoString value;
     for (const nsCSSProperty *shorthands =
            nsCSSProps::ShorthandsContaining(property);
          *shorthands != eCSSProperty_UNKNOWN; ++shorthands) {
       // ShorthandsContaining returns the shorthands in order from those
       // that contain the most subproperties to those that contain the
       // least, which is exactly the order we want to test them.
       nsCSSProperty shorthand = *shorthands;
       // If GetValue gives us a non-empty string back, we can use that
       // value; otherwise it's not possible to use this shorthand.
       GetValue(shorthand, value);
       if (!value.IsEmpty()) {
         AppendPropertyAndValueToString(shorthand, value, aString);
         shorthandsUsed.AppendElement(shorthand);
         doneProperty = true;
         break;
       }
       NS_ABORT_IF_FALSE(shorthand != eCSSProperty_font ||
                         *(shorthands + 1) == eCSSProperty_UNKNOWN,
                         "font should always be the only containing shorthand");
       if (shorthand == eCSSProperty_font) {
         if (haveSystemFont && !didSystemFont) {
           // Output the shorthand font declaration that we will
           // partially override later.  But don't add it to
           // |shorthandsUsed|, since we will have to override it.
           systemFont->AppendToString(eCSSProperty__x_system_font, value,
                                      nsCSSValue::eNormalized);
           AppendPropertyAndValueToString(eCSSProperty_font, value, aString);
           value.Truncate();
           didSystemFont = true;
         }
         // That we output the system font is enough for this property if:
         //   (1) it's the hidden system font subproperty (which either
         //       means we output it or we don't have it), or
         //   (2) its value is the hidden system font value and it matches
         //       the hidden system font subproperty in importance, and
         //       we output the system font subproperty.
         const nsCSSValue *val = systemFontData->ValueFor(property);
         if (property == eCSSProperty__x_system_font ||
             (haveSystemFont && val && val->GetUnit() == eCSSUnit_System_Font)) {
           doneProperty = true;
         }
       }
     }
     if (doneProperty)
       continue;
     NS_ABORT_IF_FALSE(value.IsEmpty(), "value should be empty now");
     AppendPropertyAndValueToString(property, value, aString);
   }
   if (! aString.IsEmpty()) {
     // if the string is not empty, we have trailing whitespace we
     // should remove
     aString.Truncate(aString.Length() - 1);
   }
 }
 #ifdef DEBUG
 void
 Declaration::List(FILE* out, int32_t aIndent) const
 {
   for (int32_t index = aIndent; --index >= 0; ) fputs("  ", out);
   fputs("{ ", out);
   nsAutoString s;
   ToString(s);
   fputs(NS_ConvertUTF16toUTF8(s).get(), out);
   fputs("}", out);
 }
 #endif
 bool
 Declaration::GetNthProperty(uint32_t aIndex, nsAString& aReturn) const
 {
   aReturn.Truncate();
   if (aIndex < mOrder.Length()) {
     nsCSSProperty property = GetPropertyAt(aIndex);
     if (property == eCSSPropertyExtra_variable) {
       GetCustomPropertyNameAt(aIndex, aReturn);
       return true;
     }
     if (0 <= property) {
       AppendASCIItoUTF16(nsCSSProps::GetStringValue(property), aReturn);
       return true;
     }
   }
   return false;
 }
 void
 Declaration::InitializeEmpty()
 {
   NS_ABORT_IF_FALSE(!mData && !mImportantData, "already initialized");
   mData = nsCSSCompressedDataBlock::CreateEmptyBlock();
 }
 Declaration*
 Declaration::EnsureMutable()
 {
   NS_ABORT_IF_FALSE(mData, "should only be called when not expanded");
   if (!IsMutable()) {
     return new Declaration(*this);
   } else {
     return this;
   }
 }
 size_t
 Declaration::SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
 {
   size_t n = aMallocSizeOf(this);
   n += mOrder.SizeOfExcludingThis(aMallocSizeOf);
   n += mData          ? mData         ->SizeOfIncludingThis(aMallocSizeOf) : 0;
   n += mImportantData ? mImportantData->SizeOfIncludingThis(aMallocSizeOf) : 0;
   if (mVariables) {
     n += mVariables->SizeOfIncludingThis(aMallocSizeOf);
   }
   if (mImportantVariables) {
     n += mImportantVariables->SizeOfIncludingThis(aMallocSizeOf);
   }
   return n;
 }
 bool
 Declaration::HasVariableDeclaration(const nsAString& aName) const
 {
   return (mVariables && mVariables->Has(aName)) ||
          (mImportantVariables && mImportantVariables->Has(aName));
 }
 void
 Declaration::GetVariableDeclaration(const nsAString& aName,
                                     nsAString& aValue) const
 {
   aValue.Truncate();
   CSSVariableDeclarations::Type type;
   nsString value;
   if ((mImportantVariables && mImportantVariables->Get(aName, type, value)) ||
       (mVariables && mVariables->Get(aName, type, value))) {
     switch (type) {
       case CSSVariableDeclarations::eTokenStream:
         aValue.Append(value);
         break;
       case CSSVariableDeclarations::eInitial:
         aValue.AppendLiteral("initial");
         break;
       case CSSVariableDeclarations::eInherit:
         aValue.AppendLiteral("inherit");
         break;
       case CSSVariableDeclarations::eUnset:
         aValue.AppendLiteral("unset");
         break;
       default:
         MOZ_ASSERT(false, "unexpected variable value type");
     }
   }
 }
 void
 Declaration::AddVariableDeclaration(const nsAString& aName,
                                     CSSVariableDeclarations::Type aType,
                                     const nsString& aValue,
                                     bool aIsImportant,
                                     bool aOverrideImportant)
 {
   MOZ_ASSERT(IsMutable());
   nsTArray<nsString>::index_type index = mVariableOrder.IndexOf(aName);
   if (index == nsTArray<nsString>::NoIndex) {
     index = mVariableOrder.Length();
     mVariableOrder.AppendElement(aName);
   }
   if (!aIsImportant && !aOverrideImportant &&
       mImportantVariables && mImportantVariables->Has(aName)) {
     return;
   }
   CSSVariableDeclarations* variables;
   if (aIsImportant) {
     if (mVariables) {
       mVariables->Remove(aName);
     }
     if (!mImportantVariables) {
       mImportantVariables = new CSSVariableDeclarations;
     }
     variables = mImportantVariables;
   } else {
     if (mImportantVariables) {
       mImportantVariables->Remove(aName);
     }
     if (!mVariables) {
       mVariables = new CSSVariableDeclarations;
     }
     variables = mVariables;
   }
   switch (aType) {
     case CSSVariableDeclarations::eTokenStream:
       variables->PutTokenStream(aName, aValue);
       break;
     case CSSVariableDeclarations::eInitial:
       MOZ_ASSERT(aValue.IsEmpty());
       variables->PutInitial(aName);
       break;
     case CSSVariableDeclarations::eInherit:
       MOZ_ASSERT(aValue.IsEmpty());
       variables->PutInherit(aName);
       break;
     case CSSVariableDeclarations::eUnset:
       MOZ_ASSERT(aValue.IsEmpty());
       variables->PutUnset(aName);
       break;
     default:
       MOZ_ASSERT(false, "unexpected aType value");
   }
   uint32_t propertyIndex = index + eCSSProperty_COUNT;
   mOrder.RemoveElement(propertyIndex);
   mOrder.AppendElement(propertyIndex);
 }
 void
 Declaration::RemoveVariableDeclaration(const nsAString& aName)
 {
   if (mVariables) {
     mVariables->Remove(aName);
   }
   if (mImportantVariables) {
     mImportantVariables->Remove(aName);
   }
   nsTArray<nsString>::index_type index = mVariableOrder.IndexOf(aName);
   if (index != nsTArray<nsString>::NoIndex) {
     mOrder.RemoveElement(index + eCSSProperty_COUNT);
   }
 }
 bool
 Declaration::GetVariableValueIsImportant(const nsAString& aName) const
 {
   return mImportantVariables && mImportantVariables->Has(aName);
 }
 } // namespace mozilla::css
 } // namespace mozilla

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layout/style/Declaration.cpp@97036ab72558 (annotated)

layout/style/Declaration.cpp