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