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/StyleSheet.h"
#include "mozilla/MemoryReporting.h"
#include "nsISupports.h"
#include "nsIDOMCSSRule.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 nsIDOMCSSRule
, public nsWrapperCache
{
protected:
Rule(uint32_t aLineNumber, uint32_t aColumnNumber)
: mSheet(nullptr),
mParentRule(nullptr),
mLineNumber(aLineNumber),
mColumnNumber(aColumnNumber)
{
}
Rule(const Rule& aCopy)
: mSheet(aCopy.mSheet),
mParentRule(aCopy.mParentRule),
mLineNumber(aCopy.mLineNumber),
mColumnNumber(aCopy.mColumnNumber)
{
}
virtual ~Rule() {}
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;
// nsIDOMCSSRule interface
NS_DECL_NSIDOMCSSRULE
#ifdef DEBUG
virtual void List(FILE* out = stdout, int32_t aIndent = 0) const = 0;
#endif
// The constants in this list must maintain the following invariants:
// If a rule of type N must appear before a rule of type M in stylesheets
// then N < M
// Note that CSSStyleSheet::RebuildChildList assumes that no other kinds of
// rules can come between two rules of type IMPORT_RULE.
enum {
UNKNOWN_RULE = 0,
CHARSET_RULE,
IMPORT_RULE,
NAMESPACE_RULE,
STYLE_RULE,
MEDIA_RULE,
FONT_FACE_RULE,
PAGE_RULE,
KEYFRAME_RULE,
KEYFRAMES_RULE,
DOCUMENT_RULE,
SUPPORTS_RULE,
FONT_FEATURE_VALUES_RULE,
COUNTER_STYLE_RULE
};
virtual int32_t GetType() const = 0;
StyleSheet* GetStyleSheet() const { return mSheet; }
// Return the document the rule lives in, if any
nsIDocument* GetDocument() const
{
StyleSheet* sheet = GetStyleSheet();
return sheet ? sheet->GetAssociatedDocument() : nullptr;
}
virtual void SetStyleSheet(StyleSheet* aSheet);
void SetParentRule(GroupRule* aRule) {
// We don't reference count this up reference. The group rule
// will tell us when it's going away or when we're detached from
// it.
mParentRule = aRule;
}
uint32_t GetLineNumber() const { return mLineNumber; }
uint32_t GetColumnNumber() const { return mColumnNumber; }
/**
* Clones |this|. Never returns nullptr.
*/
virtual already_AddRefed<Rule> Clone() const = 0;
// 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, aka helpers for nsIDOMCSSRule implementation.
virtual uint16_t Type() const = 0;
virtual void GetCssTextImpl(nsAString& aCssText) const = 0;
void GetCssText(nsAString& aCssText) const { GetCssTextImpl(aCssText); }
// XPCOM SetCssText is OK, since it never throws.
Rule* GetParentRule() const;
StyleSheet* GetParentStyleSheet() const { return GetStyleSheet(); }
nsIDocument* GetParentObject() const { return GetDocument(); }
protected:
// True if we're known-live for cycle collection purposes.
bool IsKnownLive() const;
// This is sometimes null (e.g., for style attributes).
StyleSheet* mSheet;
// When the parent GroupRule is destroyed, it will call SetParentRule(nullptr)
// on this object. (Through SetParentRuleReference);
GroupRule* 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___ */