layout/style/Rule.h

   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/dom/CSSRuleBinding.h"
  13 #include "mozilla/dom/DocumentOrShadowRoot.h"
  14 #include "mozilla/StyleSheet.h"
  15 #include "mozilla/MemoryReporting.h"
  16 #include "mozilla/WeakPtr.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___ */