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Rule.h (4730B)

      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 /* base class for all rule types in a CSS style sheet */
      8 
      9 #ifndef mozilla_css_Rule_h___
     10 #define mozilla_css_Rule_h___
     11 
     12 #include "mozilla/MemoryReporting.h"
     13 #include "mozilla/StyleSheet.h"
     14 #include "mozilla/WeakPtr.h"
     15 #include "mozilla/dom/CSSRuleBinding.h"
     16 #include "mozilla/dom/DocumentOrShadowRoot.h"
     17 #include "nsISupports.h"
     18 #include "nsWrapperCache.h"
     19 
     20 template <class T>
     21 struct already_AddRefed;
     22 
     23 namespace mozilla {
     24 
     25 enum class StyleCssRuleType : uint8_t;
     26 
     27 namespace css {
     28 class GroupRule;
     29 
     30 class Rule : public nsISupports, public nsWrapperCache, public SupportsWeakPtr {
     31 protected:
     32  Rule(StyleSheet* aSheet, Rule* aParentRule, uint32_t aLineNumber,
     33       uint32_t aColumnNumber)
     34      : mSheet(aSheet),
     35        mParentRule(aParentRule),
     36        mLineNumber(aLineNumber),
     37        mColumnNumber(aColumnNumber) {
     38 #ifdef DEBUG
     39    AssertParentRuleType();
     40 #endif
     41  }
     42 
     43 #ifdef DEBUG
     44  void AssertParentRuleType();
     45 #endif
     46 
     47  Rule(const Rule& aCopy)
     48      : mSheet(aCopy.mSheet),
     49        mParentRule(aCopy.mParentRule),
     50        mLineNumber(aCopy.mLineNumber),
     51        mColumnNumber(aCopy.mColumnNumber) {}
     52 
     53  virtual ~Rule() = default;
     54 
     55 public:
     56  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
     57  NS_DECL_CYCLE_COLLECTION_SKIPPABLE_WRAPPERCACHE_CLASS(Rule)
     58  // Return true if this rule is known to be a cycle collection leaf, in the
     59  // sense that it doesn't have any outgoing owning edges.
     60  virtual bool IsCCLeaf() const MOZ_MUST_OVERRIDE;
     61 
     62  virtual bool IsGroupRule() const { return false; }
     63 
     64 #ifdef DEBUG
     65  virtual void List(FILE* out = stdout, int32_t aIndent = 0) const = 0;
     66 #endif
     67 
     68  StyleSheet* GetStyleSheet() const { return mSheet; }
     69 
     70  // Clear the mSheet pointer on this rule and descendants.
     71  virtual void DropSheetReference();
     72 
     73  // Clear the mParentRule pointer on this rule.
     74  void DropParentRuleReference() { mParentRule = nullptr; }
     75 
     76  void DropReferences() {
     77    DropSheetReference();
     78    DropParentRuleReference();
     79  }
     80 
     81  uint32_t GetLineNumber() const { return mLineNumber; }
     82  uint32_t GetColumnNumber() const { return mColumnNumber; }
     83 
     84  // Whether this a rule in a read only style sheet.
     85  bool IsReadOnly() const;
     86 
     87  // Whether this rule is an @import rule that hasn't loaded yet (and thus
     88  // doesn't affect the style of the page).
     89  bool IsIncompleteImportRule() const;
     90 
     91  // This is pure virtual because all of Rule's data members are non-owning and
     92  // thus measured elsewhere.
     93  virtual size_t SizeOfIncludingThis(MallocSizeOf) const MOZ_MUST_OVERRIDE = 0;
     94 
     95  virtual StyleCssRuleType Type() const = 0;
     96 
     97  // WebIDL interface
     98  uint16_t TypeForBindings() const {
     99    auto type = uint16_t(Type());
    100    // Per https://drafts.csswg.org/cssom/#dom-cssrule-type for constants > 15
    101    // we return 0.
    102    return type > 15 ? 0 : type;
    103  }
    104  virtual void GetCssText(nsACString& aCssText) const = 0;
    105  void SetCssText(const nsACString& aCssText);
    106  Rule* GetParentRule() const;
    107  StyleSheet* GetParentStyleSheet() const { return GetStyleSheet(); }
    108  nsINode* GetAssociatedDocumentOrShadowRoot() const {
    109    if (!mSheet) {
    110      return nullptr;
    111    }
    112    auto* associated = mSheet->GetAssociatedDocumentOrShadowRoot();
    113    return associated ? &associated->AsNode() : nullptr;
    114  }
    115  nsISupports* GetParentObject() const { return mSheet; }
    116 
    117  struct ContainingRuleState {
    118    uint32_t mContainingTypes = 0;
    119    Maybe<StyleCssRuleType> mParseRelativeType;
    120 
    121    static ContainingRuleState From(Rule* aRule) {
    122      return aRule ? aRule->GetContainingRuleStateForParsing()
    123                   : ContainingRuleState();
    124    }
    125  };
    126  ContainingRuleState GetContainingRuleStateForParsing() const;
    127 
    128 protected:
    129  // True if we're known-live for cycle collection purposes.
    130  bool IsKnownLive() const;
    131 
    132  // Hook subclasses can use to properly unlink the nsWrapperCache of
    133  // their declarations.
    134  void UnlinkDeclarationWrapper(nsWrapperCache& aDecl);
    135 
    136  // mSheet should only ever be null when we create a synthetic CSSFontFaceRule
    137  // for an InspectorFontFace.
    138  //
    139  // mSheet and mParentRule will be cleared when they are detached from the
    140  // parent object, either because the rule is removed or the parent is
    141  // destroyed.
    142  StyleSheet* MOZ_NON_OWNING_REF mSheet;
    143  Rule* MOZ_NON_OWNING_REF mParentRule;
    144 
    145  // Keep the same type so that MSVC packs them.
    146  uint32_t mLineNumber;
    147  uint32_t mColumnNumber;
    148 };
    149 
    150 }  // namespace css
    151 }  // namespace mozilla
    152 
    153 #endif /* mozilla_css_Rule_h___ */