gecko-dev/xpcom/ds/nsIAtom.idl

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/*
 * The contents of this file are subject to the Netscape Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/NPL/
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code is Mozilla Communicator client code, 
 * released March 31, 1998. 
 *
 * The Initial Developer of the Original Code is Netscape Communications 
 * Corporation.  Portions created by Netscape are
 * Copyright (C) 1998-1999 Netscape Communications Corporation. All
 * Rights Reserved.
 *
 * Contributor(s): 
 *     
 */
#include "nsISupports.idl"

%{C++
#include "nsAString.h"
#include "nsCOMPtr.h"
%}

/*
 * Should this really be scriptable?  Using atoms from script or proxies
 * could be dangerous since double-wrapping could lead to loss of
 * pointer identity.
 */
 
[scriptable, uuid(3d1b15b0-93b4-11d1-895b-006008911b81)]
interface nsIAtom : nsISupports
{
  /**
   * Get the Unicode or UTF8 value for the string
   */
  AString toString(); 
  AUTF8String toUTF8String();
  
  /**
   * Return a pointer to a zero terminated UTF8 string.
   */
  [noscript] void getUTF8String([shared, retval] out string aResult);

  /**
   * Compare the atom to a specific string value
   * Note that this will NEVER return/throw an error condition.
   */
  boolean equals(in AString aString);
  
  boolean equalsUTF8(in AUTF8String aString);

%{C++
  // note this is NOT virtual so this won't muck with the vtable!
  inline PRBool Equals(const nsAString& s) {
    PRBool result;
    Equals(s, &result);
    return result;
  }

  inline PRBool EqualsUTF8(const nsACString& s) {
    PRBool result;
    EqualsUTF8(s, &result);
    return result;
  }
%}
  
};


%{C++
/*
 * The three forms of NS_NewAtom and do_GetAtom (for use with
 * |nsCOMPtr<nsIAtom>|) return the atom for the string given.  At any
 * given time there will always be one atom representing a given string.
 * Atoms are intended to make string comparison cheaper by simplifying
 * it to pointer equality.  A pointer to the atom that does not own a
 * reference is not guaranteed to be valid.
 *
 * The three forms of NS_NewPermanentAtom and do_GetPermanentAtom return
 * the atom for the given string and ensure that the atom is permanent.
 * An atom that is permanent will exist (occupy space at a specific
 * location in memory) until XPCOM is shut down.  The advantage of
 * permanent atoms is that they do not need to maintain a reference
 * count, which requires locking and hurts performance.
 */


/**
 * Find an atom that matches the given UTF-8 string.
 * The string is assumed to be zero terminated.
 */
extern NS_COM nsIAtom* NS_NewAtom(const char* aUTF8String);
extern NS_COM nsIAtom* NS_NewPermanentAtom(const char* aUTF8String);

inline already_AddRefed<nsIAtom> do_GetAtom(const char* aUTF8String)
    { return NS_NewAtom(aUTF8String); }
inline already_AddRefed<nsIAtom> do_GetPermanentAtom(const char* aUTF8String)
    { return NS_NewPermanentAtom(aUTF8String); }
 
/**
 * Find an atom that matches the given UTF-8 string.
 */
extern NS_COM nsIAtom* NS_NewAtom(const nsACString& aUTF8String);
extern NS_COM nsIAtom* NS_NewPermanentAtom(const nsACString& aUTF8String);

inline already_AddRefed<nsIAtom> do_GetAtom(const nsACString& aUTF8String)
    { return NS_NewAtom(aUTF8String); }
inline already_AddRefed<nsIAtom> do_GetPermanentAtom(const nsACString& aUTF8String)
    { return NS_NewPermanentAtom(aUTF8String); }

/**
 * Find an atom that matches the given UTF-16 string.
 * The string is assumed to be zero terminated.
 */
extern NS_COM nsIAtom* NS_NewAtom(const PRUnichar* aUTF16String);
extern NS_COM nsIAtom* NS_NewPermanentAtom(const PRUnichar* aUTF16String);

inline already_AddRefed<nsIAtom> do_GetAtom(const PRUnichar* aUTF16String)
    { return NS_NewAtom(aUTF16String); }
inline already_AddRefed<nsIAtom> do_GetPermanentAtom(const PRUnichar* aUTF16String)
    { return NS_NewPermanentAtom(aUTF16String); }

/**
 * Find an atom that matches the given UTF-16 string.
 */
extern NS_COM nsIAtom* NS_NewAtom(const nsAString& aUTF16String);
extern NS_COM nsIAtom* NS_NewPermanentAtom(const nsAString& aUTF16String);

inline already_AddRefed<nsIAtom> do_GetAtom(const nsAString& aUTF16String)
    { return NS_NewAtom(aUTF16String); }
inline already_AddRefed<nsIAtom> do_GetPermanentAtom(const nsAString& aUTF16String)
    { return NS_NewPermanentAtom(aUTF16String); }

/**
 * Return a count of the total number of atoms currently
 * alive in the system.
 */
extern NS_COM nsrefcnt NS_GetNumberOfAtoms(void);

%}