gecko-dev/layout/style/Rule.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* base class for all rule types in a CSS style sheet */
#ifndef mozilla_css_Rule_h___
#define mozilla_css_Rule_h___
#include "mozilla/dom/CSSRuleBinding.h"
#include "mozilla/dom/DocumentOrShadowRoot.h"
#include "mozilla/StyleSheet.h"
#include "mozilla/MemoryReporting.h"
#include "nsISupports.h"
#include "nsWrapperCache.h"
class nsIDocument;
struct nsRuleData;
template<class T> struct already_AddRefed;
class nsHTMLCSSStyleSheet;
namespace mozilla {
namespace css {
class GroupRule;
class Rule : public nsISupports
, public nsWrapperCache
{
protected:
Rule(StyleSheet* aSheet,
Rule* aParentRule,
uint32_t aLineNumber,
uint32_t aColumnNumber)
: mSheet(aSheet)
, mParentRule(aParentRule)
, mLineNumber(aLineNumber)
, mColumnNumber(aColumnNumber)
{
#ifdef DEBUG
// Would be nice to check that this->Type() is KEYFRAME_RULE when
// mParentRule->Tye() is KEYFRAMES_RULE, but we can't call
// this->Type() here since it's virtual.
if (mParentRule) {
int16_t type = mParentRule->Type();
MOZ_ASSERT(type == dom::CSSRule_Binding::MEDIA_RULE ||
type == dom::CSSRule_Binding::DOCUMENT_RULE ||
type == dom::CSSRule_Binding::SUPPORTS_RULE ||
type == dom::CSSRule_Binding::KEYFRAMES_RULE);
}
#endif
}
Rule(const Rule& aCopy)
: mSheet(aCopy.mSheet),
mParentRule(aCopy.mParentRule),
mLineNumber(aCopy.mLineNumber),
mColumnNumber(aCopy.mColumnNumber)
{
}
virtual ~Rule() = default;
public:
NS_DECL_CYCLE_COLLECTING_ISUPPORTS
NS_DECL_CYCLE_COLLECTION_SKIPPABLE_SCRIPT_HOLDER_CLASS(Rule)
// Return true if this rule is known to be a cycle collection leaf, in the
// sense that it doesn't have any outgoing owning edges.
virtual bool IsCCLeaf() const MOZ_MUST_OVERRIDE;
#ifdef DEBUG
virtual void List(FILE* out = stdout, int32_t aIndent = 0) const = 0;
#endif
StyleSheet* GetStyleSheet() const { return mSheet; }
// Return the document the rule applies to, if any.
//
// Suitable for style updates, and that's about it.
nsIDocument* GetComposedDoc() const
{
return mSheet ? mSheet->GetComposedDoc() : nullptr;
}
// Clear the mSheet pointer on this rule and descendants.
virtual void DropSheetReference();
// Clear the mParentRule pointer on this rule.
void DropParentRuleReference()
{
mParentRule = nullptr;
}
void DropReferences()
{
DropSheetReference();
DropParentRuleReference();
}
uint32_t GetLineNumber() const { return mLineNumber; }
uint32_t GetColumnNumber() const { return mColumnNumber; }
// This is pure virtual because all of Rule's data members are non-owning and
// thus measured elsewhere.
virtual size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf)
const MOZ_MUST_OVERRIDE = 0;
// WebIDL interface
virtual uint16_t Type() const = 0;
virtual void GetCssText(nsAString& aCssText) const = 0;
void SetCssText(const nsAString& aCssText);
Rule* GetParentRule() const;
StyleSheet* GetParentStyleSheet() const { return GetStyleSheet(); }
nsINode* GetParentObject() const
{
if (!mSheet) {
return nullptr;
}
auto* associated = mSheet->GetAssociatedDocumentOrShadowRoot();
return associated ? &associated->AsNode() : nullptr;
}
protected:
// True if we're known-live for cycle collection purposes.
bool IsKnownLive() const;
// mSheet should only ever be null when we create a synthetic CSSFontFaceRule
// for an InspectorFontFace.
//
// mSheet and mParentRule will be cleared when they are detached from the
// parent object, either because the rule is removed or the parent is
// destroyed.
StyleSheet* MOZ_NON_OWNING_REF mSheet;
Rule* MOZ_NON_OWNING_REF mParentRule;
// Keep the same type so that MSVC packs them.
uint32_t mLineNumber;
uint32_t mColumnNumber;
};
} // namespace css
} // namespace mozilla
#endif /* mozilla_css_Rule_h___ */