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 namespace css {
  26 class GroupRule;
  27
  28 class Rule : public nsISupports, public nsWrapperCache {
  29  protected:
  30   Rule(StyleSheet* aSheet, Rule* aParentRule, uint32_t aLineNumber,
  31        uint32_t aColumnNumber)
  32       : mSheet(aSheet),
  33         mParentRule(aParentRule),
  34         mLineNumber(aLineNumber),
  35         mColumnNumber(aColumnNumber) {
  36 #ifdef DEBUG
  37     // Would be nice to check that this->Type() is KEYFRAME_RULE when
  38     // mParentRule->Tye() is KEYFRAMES_RULE, but we can't call
  39     // this->Type() here since it's virtual.
  40     if (mParentRule) {
  41       int16_t type = mParentRule->Type();
  42       MOZ_ASSERT(type == dom::CSSRule_Binding::MEDIA_RULE ||
  43                  type == dom::CSSRule_Binding::DOCUMENT_RULE ||
  44                  type == dom::CSSRule_Binding::SUPPORTS_RULE ||
  45                  type == dom::CSSRule_Binding::KEYFRAMES_RULE);
  46     }
  47 #endif
  48   }
  49
  50   Rule(const Rule& aCopy)
  51       : mSheet(aCopy.mSheet),
  52         mParentRule(aCopy.mParentRule),
  53         mLineNumber(aCopy.mLineNumber),
  54         mColumnNumber(aCopy.mColumnNumber) {}
  55
  56   virtual ~Rule() = default;
  57
  58  public:
  59   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  60   NS_DECL_CYCLE_COLLECTION_SKIPPABLE_SCRIPT_HOLDER_CLASS(Rule)
  61   // Return true if this rule is known to be a cycle collection leaf, in the
  62   // sense that it doesn't have any outgoing owning edges.
  63   virtual bool IsCCLeaf() const MOZ_MUST_OVERRIDE;
  64
  65 #ifdef DEBUG
  66   virtual void List(FILE* out = stdout, int32_t aIndent = 0) const = 0;
  67 #endif
  68
  69   StyleSheet* GetStyleSheet() const { return mSheet; }
  70
  71   // Clear the mSheet pointer on this rule and descendants.
  72   virtual void DropSheetReference();
  73
  74   // Clear the mParentRule pointer on this rule.
  75   void DropParentRuleReference() { mParentRule = nullptr; }
  76
  77   void DropReferences() {
  78     DropSheetReference();
  79     DropParentRuleReference();
  80   }
  81
  82   uint32_t GetLineNumber() const { return mLineNumber; }
  83   uint32_t GetColumnNumber() const { return mColumnNumber; }
  84
  85   // Whether this a rule in a read only style sheet.
  86   bool IsReadOnly() const;
  87
  88   // Whether this rule is an @import rule that hasn't loaded yet (and thus
  89   // doesn't affect the style of the page).
  90   bool IsIncompleteImportRule() const;
  91
  92   // This is pure virtual because all of Rule's data members are non-owning and
  93   // thus measured elsewhere.
  94   virtual size_t SizeOfIncludingThis(MallocSizeOf) const MOZ_MUST_OVERRIDE = 0;
  95
  96   // WebIDL interface
  97   virtual uint16_t Type() const = 0;
  98   virtual void GetCssText(nsAString& aCssText) const = 0;
  99   void SetCssText(const nsAString& aCssText);
 100   Rule* GetParentRule() const;
 101   StyleSheet* GetParentStyleSheet() const { return GetStyleSheet(); }
 102   nsINode* GetParentObject() const {
 103     if (!mSheet) {
 104       return nullptr;
 105     }
 106     auto* associated = mSheet->GetAssociatedDocumentOrShadowRoot();
 107     return associated ? &associated->AsNode() : nullptr;
 108   }
 109
 110  protected:
 111   // True if we're known-live for cycle collection purposes.
 112   bool IsKnownLive() const;
 113
 114   // Hook subclasses can use to properly unlink the nsWrapperCache of
 115   // their declarations.
 116   void UnlinkDeclarationWrapper(nsWrapperCache& aDecl);
 117
 118   // mSheet should only ever be null when we create a synthetic CSSFontFaceRule
 119   // for an InspectorFontFace.
 120   //
 121   // mSheet and mParentRule will be cleared when they are detached from the
 122   // parent object, either because the rule is removed or the parent is
 123   // destroyed.
 124   StyleSheet* MOZ_NON_OWNING_REF mSheet;
 125   Rule* MOZ_NON_OWNING_REF mParentRule;
 126
 127   // Keep the same type so that MSVC packs them.
 128   uint32_t mLineNumber;
 129   uint32_t mColumnNumber;
 130 };
 131
 132 }  // namespace css
 133 }  // namespace mozilla
 134
 135 #endif /* mozilla_css_Rule_h___ */