gecko-dev/xpcom/ds/nsIAtom.idl

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */
#include "nsISupports.idl"
%{C++
#include "nsStringGlue.h"
#include "nsCOMPtr.h"
#include "nsStringBuffer.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, builtinclass, uuid(1f341018-521a-49de-b806-1bef5c9a00b0)]
interface nsIAtom : nsISupports
{
/**
* Get the Unicode or UTF8 value for the string
*/
[binaryname(ScriptableToString)] AString toString();
[noscript] AUTF8String toUTF8String();
/**
* Compare the atom to a specific string value
* Note that this will NEVER return/throw an error condition.
*/
[binaryname(ScriptableEquals)] boolean equals(in AString aString);
[noscript, notxpcom] boolean equalsUTF8(in AUTF8String aString);
/**
* Returns true if the atom is static and false otherwise.
*/
[noscript, notxpcom] boolean isStaticAtom();
%{C++
// note this is NOT virtual so this won't muck with the vtable!
inline bool Equals(const nsAString& aString) {
return aString.Equals(nsDependentString(mString, mLength));
}
inline const PRUnichar* GetUTF16String() {
return mString;
}
inline const uint32_t GetLength() {
return mLength;
}
inline void ToString(nsAString& aBuf) {
nsStringBuffer::FromData(mString)->ToString(mLength, aBuf);
}
/**
* A hashcode that is better distributed than the actual atom
* pointer, for use in situations that need a well-distributed
* hashcode.
*/
inline uint32_t hash() const {
return mHash;
}
protected:
uint32_t mLength;
uint32_t mHash;
PRUnichar* mString;
%}
};
%{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 nsIAtom* NS_NewAtom(const char* aUTF8String);
inline already_AddRefed<nsIAtom> do_GetAtom(const char* aUTF8String)
{ return NS_NewAtom(aUTF8String); }
/**
* Find an atom that matches the given UTF-8 string.
*/
extern nsIAtom* NS_NewAtom(const nsACString& aUTF8String);
inline already_AddRefed<nsIAtom> do_GetAtom(const nsACString& aUTF8String)
{ return NS_NewAtom(aUTF8String); }
/**
* Find an atom that matches the given UTF-16 string.
* The string is assumed to be zero terminated.
*/
extern nsIAtom* NS_NewAtom(const PRUnichar* aUTF16String);
inline already_AddRefed<nsIAtom> do_GetAtom(const PRUnichar* aUTF16String)
{ return NS_NewAtom(aUTF16String); }
/**
* Find an atom that matches the given UTF-16 string.
*/
extern nsIAtom* NS_NewAtom(const nsAString& aUTF16String);
extern nsIAtom* NS_NewPermanentAtom(const nsAString& aUTF16String);
inline already_AddRefed<nsIAtom> do_GetAtom(const nsAString& aUTF16String)
{ return NS_NewAtom(aUTF16String); }
/**
* Return a count of the total number of atoms currently
* alive in the system.
*/
extern nsrefcnt NS_GetNumberOfAtoms(void);
/**
* Return a pointer for a static atom for the string or null if there's
* no static atom for this string.
*/
extern nsIAtom* NS_GetStaticAtom(const nsAString& aUTF16String);
/**
* Seal the static atom table
*/
extern void NS_SealStaticAtomTable();
class nsAtomString : public nsString
{
public:
nsAtomString(nsIAtom* aAtom)
{
aAtom->ToString(*this);
}
};
class nsAtomCString : public nsCString
{
public:
nsAtomCString(nsIAtom* aAtom)
{
aAtom->ToUTF8String(*this);
}
};
class nsDependentAtomString : public nsDependentString
{
public:
nsDependentAtomString(nsIAtom* aAtom)
: nsDependentString(aAtom->GetUTF16String(), aAtom->GetLength())
{
}
};
%}