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/* internal interface for all rule types in a CSS style sheet */

#ifndef nsICSSRule_h
#define nsICSSRule_h

#include "nsIStyleRule.h"
#include "nsIDOMCSSRule.h"

class nsCSSStyleSheet;
class nsICSSGroupRule;
class nsAString;
template<class T> struct already_AddRefed;
class nsIStyleSheet;

// IID for the nsICSSRule interface
#define NS_ICSS_RULE_IID \
{ 0x1f560b20, 0xa829, 0x4b99, \
  { 0x87, 0xbd, 0x8c, 0x87, 0x95, 0x2b, 0x3b, 0xb6 } }


// inheriting from nsIStyleRule is only for style rules, not other rule types
class nsICSSRule : public nsIStyleRule {
public:
  NS_DECLARE_STATIC_IID_ACCESSOR(NS_ICSS_RULE_IID)
  // 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 nsCSSStyleSheet::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,
    DOCUMENT_RULE
  };

  virtual PRInt32 GetType() const = 0;

  virtual already_AddRefed<nsIStyleSheet> GetStyleSheet() const = 0;
  virtual void SetStyleSheet(nsCSSStyleSheet* aSheet) = 0;
  virtual void SetParentRule(nsICSSGroupRule* aRule) = 0;

  /**
   * Clones |this|. Never returns NULL.
   */
  virtual already_AddRefed<nsICSSRule> Clone() const = 0;

  // Note that this returns null for inline style rules since they aren't
  // supposed to have a DOM rule representation (and our code wouldn't work).
  nsresult GetDOMRule(nsIDOMCSSRule** aDOMRule)
  {
    nsresult rv;
    NS_IF_ADDREF(*aDOMRule = GetDOMRuleWeak(&rv));
    return rv;
  }
  virtual nsIDOMCSSRule* GetDOMRuleWeak(nsresult* aResult) = 0;
};

NS_DEFINE_STATIC_IID_ACCESSOR(nsICSSRule, NS_ICSS_RULE_IID)

/* Define global NS_New* functions for rules that don't need their own
   interfaces here */
nsresult
NS_NewCSSCharsetRule(nsICSSRule** aInstancePtrResult,
                     const nsAString& aEncoding);

#endif /* nsICSSRule_h */