layout/style/ServoCSSRuleList.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 /* representation of CSSRuleList for stylo */
   8
   9 #include "mozilla/ServoCSSRuleList.h"
  10
  11 #include "mozilla/dom/CSSCounterStyleRule.h"
  12 #include "mozilla/dom/CSSFontFaceRule.h"
  13 #include "mozilla/dom/CSSFontFeatureValuesRule.h"
  14 #include "mozilla/dom/CSSFontPaletteValuesRule.h"
  15 #include "mozilla/dom/CSSImportRule.h"
  16 #include "mozilla/dom/CSSLayerBlockRule.h"
  17 #include "mozilla/dom/CSSLayerStatementRule.h"
  18 #include "mozilla/dom/CSSKeyframesRule.h"
  19 #include "mozilla/dom/CSSContainerRule.h"
  20 #include "mozilla/dom/CSSMediaRule.h"
  21 #include "mozilla/dom/CSSMozDocumentRule.h"
  22 #include "mozilla/dom/CSSNamespaceRule.h"
  23 #include "mozilla/dom/CSSPageRule.h"
  24 #include "mozilla/dom/CSSPropertyRule.h"
  25 #include "mozilla/dom/CSSScopeRule.h"
  26 #include "mozilla/dom/CSSStartingStyleRule.h"
  27 #include "mozilla/dom/CSSStyleRule.h"
  28 #include "mozilla/dom/CSSSupportsRule.h"
  29 #include "mozilla/IntegerRange.h"
  30 #include "mozilla/ServoBindings.h"
  31 #include "mozilla/StyleSheet.h"
  32 #include "mozilla/dom/Document.h"
  33
  34 using namespace mozilla::dom;
  35
  36 namespace mozilla {
  37
  38 ServoCSSRuleList::ServoCSSRuleList(
  39     already_AddRefed<StyleLockedCssRules> aRawRules, StyleSheet* aSheet,
  40     css::GroupRule* aParentRule)
  41     : mStyleSheet(aSheet), mParentRule(aParentRule), mRawRules(aRawRules) {
  42   ResetRules();
  43 }
  44
  45 // QueryInterface implementation for ServoCSSRuleList
  46 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(ServoCSSRuleList)
  47 NS_INTERFACE_MAP_END_INHERITING(dom::CSSRuleList)
  48
  49 NS_IMPL_ADDREF_INHERITED(ServoCSSRuleList, dom::CSSRuleList)
  50 NS_IMPL_RELEASE_INHERITED(ServoCSSRuleList, dom::CSSRuleList)
  51
  52 NS_IMPL_CYCLE_COLLECTION_CLASS(ServoCSSRuleList)
  53
  54 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(ServoCSSRuleList)
  55   tmp->DropAllRules();
  56 NS_IMPL_CYCLE_COLLECTION_UNLINK_END_INHERITED(dom::CSSRuleList)
  57 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(ServoCSSRuleList,
  58                                                   dom::CSSRuleList)
  59   tmp->EnumerateInstantiatedRules([&](css::Rule* aRule, uint32_t) {
  60     if (!aRule->IsCCLeaf()) {
  61       NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mRules[i]");
  62       cb.NoteXPCOMChild(aRule);
  63     }
  64   });
  65 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
  66
  67 css::Rule* ServoCSSRuleList::GetRule(uint32_t aIndex) {
  68   uintptr_t rule = mRules[aIndex];
  69   if (rule <= kMaxRuleType) {
  70     RefPtr<css::Rule> ruleObj = nullptr;
  71     switch (StyleCssRuleType(rule)) {
  72 #define CASE_RULE_WITH_PREFIX(const_, prefix_, name_)                         \
  73   case StyleCssRuleType::const_: {                                            \
  74     uint32_t line = 0, column = 0;                                            \
  75     RefPtr<Style##prefix_##const_##Rule> raw =                                \
  76         Servo_CssRules_Get##const_##RuleAt(mRawRules, aIndex, &line, &column) \
  77             .Consume();                                                       \
  78     MOZ_ASSERT(raw);                                                          \
  79     ruleObj = new CSS##name_##Rule(raw.forget(), mStyleSheet, mParentRule,    \
  80                                    line, column);                             \
  81     MOZ_ASSERT(ruleObj->Type() == StyleCssRuleType(rule));                    \
  82     break;                                                                    \
  83   }
  84 #define CASE_RULE_LOCKED(const_, name_) \
  85   CASE_RULE_WITH_PREFIX(const_, Locked, name_)
  86 #define CASE_RULE_UNLOCKED(const_, name_) CASE_RULE_WITH_PREFIX(const_, , name_)
  87       CASE_RULE_LOCKED(Style, Style)
  88       CASE_RULE_LOCKED(Keyframes, Keyframes)
  89       CASE_RULE_UNLOCKED(Media, Media)
  90       CASE_RULE_UNLOCKED(Namespace, Namespace)
  91       CASE_RULE_LOCKED(Page, Page)
  92       CASE_RULE_UNLOCKED(Property, Property)
  93       CASE_RULE_UNLOCKED(Supports, Supports)
  94       CASE_RULE_UNLOCKED(Document, MozDocument)
  95       CASE_RULE_LOCKED(Import, Import)
  96       CASE_RULE_UNLOCKED(FontFeatureValues, FontFeatureValues)
  97       CASE_RULE_UNLOCKED(FontPaletteValues, FontPaletteValues)
  98       CASE_RULE_LOCKED(FontFace, FontFace)
  99       CASE_RULE_LOCKED(CounterStyle, CounterStyle)
 100       CASE_RULE_UNLOCKED(LayerBlock, LayerBlock)
 101       CASE_RULE_UNLOCKED(LayerStatement, LayerStatement)
 102       CASE_RULE_UNLOCKED(Container, Container)
 103       CASE_RULE_UNLOCKED(Scope, Scope)
 104       CASE_RULE_UNLOCKED(StartingStyle, StartingStyle)
 105 #undef CASE_RULE_LOCKED
 106 #undef CASE_RULE_UNLOCKED
 107 #undef CASE_RULE_WITH_PREFIX
 108       case StyleCssRuleType::Keyframe:
 109         MOZ_ASSERT_UNREACHABLE("keyframe rule cannot be here");
 110         return nullptr;
 111       case StyleCssRuleType::Margin:
 112         // Margin rules not implemented yet, see bug 1864737
 113         return nullptr;
 114     }
 115     rule = CastToUint(ruleObj.forget().take());
 116     mRules[aIndex] = rule;
 117   }
 118   return CastToPtr(rule);
 119 }
 120
 121 css::Rule* ServoCSSRuleList::IndexedGetter(uint32_t aIndex, bool& aFound) {
 122   if (aIndex >= mRules.Length()) {
 123     aFound = false;
 124     return nullptr;
 125   }
 126   aFound = true;
 127   return GetRule(aIndex);
 128 }
 129
 130 template <typename Func>
 131 void ServoCSSRuleList::EnumerateInstantiatedRules(Func aCallback) {
 132   uint32_t index = 0;
 133   for (uintptr_t rule : mRules) {
 134     if (rule > kMaxRuleType) {
 135       aCallback(CastToPtr(rule), index);
 136     }
 137     index++;
 138   }
 139 }
 140
 141 static void DropRule(already_AddRefed<css::Rule> aRule) {
 142   RefPtr<css::Rule> rule = aRule;
 143   rule->DropReferences();
 144 }
 145
 146 void ServoCSSRuleList::ResetRules() {
 147   // DropRule could reenter here via the cycle collector.
 148   auto rules = std::move(mRules);
 149   for (uintptr_t rule : rules) {
 150     if (rule > kMaxRuleType) {
 151       DropRule(already_AddRefed<css::Rule>(CastToPtr(rule)));
 152     }
 153   }
 154   MOZ_ASSERT(mRules.IsEmpty());
 155   if (mRawRules) {
 156     Servo_CssRules_ListTypes(mRawRules, &mRules);
 157   }
 158 }
 159
 160 void ServoCSSRuleList::DropAllRules() {
 161   mStyleSheet = nullptr;
 162   mParentRule = nullptr;
 163   mRawRules = nullptr;
 164
 165   ResetRules();
 166 }
 167
 168 void ServoCSSRuleList::DropSheetReference() {
 169   // If mStyleSheet is not set on this rule list, then it is not set on any of
 170   // its instantiated rules either.  To avoid O(N^2) beavhior in the depth of
 171   // group rule nesting, which can happen if we are unlinked starting from the
 172   // deepest nested group rule, skip recursing into the rule list if we know we
 173   // don't need to.
 174   if (!mStyleSheet) {
 175     return;
 176   }
 177   mStyleSheet = nullptr;
 178   EnumerateInstantiatedRules(
 179       [](css::Rule* rule, uint32_t) { rule->DropSheetReference(); });
 180 }
 181
 182 void ServoCSSRuleList::DropParentRuleReference() {
 183   mParentRule = nullptr;
 184   EnumerateInstantiatedRules(
 185       [](css::Rule* rule, uint32_t) { rule->DropParentRuleReference(); });
 186 }
 187
 188 nsresult ServoCSSRuleList::InsertRule(const nsACString& aRule,
 189                                       uint32_t aIndex) {
 190   MOZ_ASSERT(mStyleSheet,
 191              "Caller must ensure that "
 192              "the list is not unlinked from stylesheet");
 193
 194   if (!mRawRules || IsReadOnly()) {
 195     return NS_OK;
 196   }
 197
 198   mStyleSheet->WillDirty();
 199
 200   css::Loader* loader = nullptr;
 201   auto allowImportRules = mStyleSheet->SelfOrAncestorIsConstructed()
 202                               ? StyleAllowImportRules::No
 203                               : StyleAllowImportRules::Yes;
 204
 205   // TODO(emilio, bug 1535456): Should probably always be able to get a handle
 206   // to some loader if we're parsing an @import rule, but which one?
 207   //
 208   // StyleSheet::ReparseSheet just mints a new loader, but that'd be wrong in
 209   // this case I think, since such a load will bypass CSP checks.
 210   if (Document* doc = mStyleSheet->GetAssociatedDocument()) {
 211     loader = doc->CSSLoader();
 212   }
 213   StyleCssRuleType type;
 214   uint32_t containingTypes = 0;
 215   Maybe<StyleCssRuleType> parseRelativeRuleType;
 216   for (css::Rule* rule = mParentRule; rule; rule = rule->GetParentRule()) {
 217     const auto ruleType = rule->Type();
 218     containingTypes |= (1 << uint32_t(ruleType));
 219     if (parseRelativeRuleType.isNothing() &&
 220         (ruleType == StyleCssRuleType::Style ||
 221          ruleType == StyleCssRuleType::Scope)) {
 222       // Only the closest applicable type to this rule matters.
 223       parseRelativeRuleType = Some(ruleType);
 224     }
 225   }
 226   nsresult rv = Servo_CssRules_InsertRule(
 227       mRawRules, mStyleSheet->RawContents(), &aRule, aIndex, containingTypes,
 228       parseRelativeRuleType.ptrOr(nullptr), loader, allowImportRules,
 229       mStyleSheet, &type);
 230   NS_ENSURE_SUCCESS(rv, rv);
 231   mRules.InsertElementAt(aIndex, uintptr_t(type));
 232   return rv;
 233 }
 234
 235 nsresult ServoCSSRuleList::DeleteRule(uint32_t aIndex) {
 236   if (!mRawRules || IsReadOnly()) {
 237     return NS_OK;
 238   }
 239
 240   nsresult rv = Servo_CssRules_DeleteRule(mRawRules, aIndex);
 241   if (!NS_FAILED(rv)) {
 242     uintptr_t rule = mRules[aIndex];
 243     mRules.RemoveElementAt(aIndex);
 244     if (rule > kMaxRuleType) {
 245       DropRule(already_AddRefed<css::Rule>(CastToPtr(rule)));
 246     }
 247   }
 248   return rv;
 249 }
 250
 251 void ServoCSSRuleList::SetRawContents(RefPtr<StyleLockedCssRules> aNewRules,
 252                                       bool aFromClone) {
 253   mRawRules = std::move(aNewRules);
 254   if (!aFromClone) {
 255     ResetRules();
 256     return;
 257   }
 258
 259   EnumerateInstantiatedRules([&](css::Rule* aRule, uint32_t aIndex) {
 260 #define RULE_CASE_WITH_PREFIX(constant_, prefix_, type_)                \
 261   case StyleCssRuleType::constant_: {                                   \
 262     uint32_t line = 0, column = 0;                                      \
 263     RefPtr<Style##prefix_##constant_##Rule> raw =                       \
 264         Servo_CssRules_Get##constant_##RuleAt(mRawRules, aIndex, &line, \
 265                                               &column)                  \
 266             .Consume();                                                 \
 267     static_cast<dom::CSS##type_##Rule*>(aRule)->SetRawAfterClone(       \
 268         std::move(raw));                                                \
 269     break;                                                              \
 270   }
 271 #define RULE_CASE_LOCKED(constant_, type_) \
 272   RULE_CASE_WITH_PREFIX(constant_, Locked, type_)
 273 #define RULE_CASE_UNLOCKED(constant_, type_) \
 274   RULE_CASE_WITH_PREFIX(constant_, , type_)
 275     switch (aRule->Type()) {
 276       RULE_CASE_LOCKED(Style, Style)
 277       RULE_CASE_LOCKED(Keyframes, Keyframes)
 278       RULE_CASE_UNLOCKED(Media, Media)
 279       RULE_CASE_UNLOCKED(Namespace, Namespace)
 280       RULE_CASE_LOCKED(Page, Page)
 281       RULE_CASE_UNLOCKED(Property, Property)
 282       RULE_CASE_UNLOCKED(Supports, Supports)
 283       RULE_CASE_UNLOCKED(Document, MozDocument)
 284       RULE_CASE_LOCKED(Import, Import)
 285       RULE_CASE_UNLOCKED(FontFeatureValues, FontFeatureValues)
 286       RULE_CASE_UNLOCKED(FontPaletteValues, FontPaletteValues)
 287       RULE_CASE_LOCKED(FontFace, FontFace)
 288       RULE_CASE_LOCKED(CounterStyle, CounterStyle)
 289       RULE_CASE_UNLOCKED(LayerBlock, LayerBlock)
 290       RULE_CASE_UNLOCKED(LayerStatement, LayerStatement)
 291       RULE_CASE_UNLOCKED(Container, Container)
 292       RULE_CASE_UNLOCKED(Scope, Scope)
 293       RULE_CASE_UNLOCKED(StartingStyle, StartingStyle)
 294       case StyleCssRuleType::Keyframe:
 295         MOZ_ASSERT_UNREACHABLE("keyframe rule cannot be here");
 296         break;
 297       case StyleCssRuleType::Margin:
 298         // Margin rules not implemented yet, see bug 1864737
 299         break;
 300     }
 301 #undef RULE_CASE_WITH_PREFIX
 302 #undef RULE_CASE_LOCKED
 303 #undef RULE_CASE_UNLOCKED
 304   });
 305 }
 306
 307 ServoCSSRuleList::~ServoCSSRuleList() {
 308   MOZ_ASSERT(!mStyleSheet, "Backpointer should have been cleared");
 309   MOZ_ASSERT(!mParentRule, "Backpointer should have been cleared");
 310   DropAllRules();
 311 }
 312
 313 bool ServoCSSRuleList::IsReadOnly() const {
 314   MOZ_ASSERT(!mStyleSheet || !mParentRule ||
 315                  mStyleSheet->IsReadOnly() == mParentRule->IsReadOnly(),
 316              "a parent rule should be read only iff the owning sheet is "
 317              "read only");
 318   return mStyleSheet && mStyleSheet->IsReadOnly();
 319 }
 320
 321 }  // namespace mozilla