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