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"
%}
native MallocSizeOf(mozilla::MallocSizeOf);
/*
* 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(8b8c11d4-3ed5-4079-8974-73c7576cdb34)]
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]
size_t SizeOfIncludingThis(in MallocSizeOf aMallocSizeOf);
%{C++
// note this is NOT virtual so this won't muck with the vtable!
inline bool Equals(const nsAString& aString) const {
return aString.Equals(nsDependentString(mString, mLength));
}
inline bool IsStaticAtom() const {
return mIsStatic;
}
inline char16ptr_t GetUTF16String() const {
return mString;
}
inline uint32_t GetLength() const {
return mLength;
}
inline void ToString(nsAString& aBuf) {
// See the comment on |mString|'s declaration.
nsStringBuffer::FromData(mString)->ToString(mLength, aBuf);
}
inline nsStringBuffer* GetStringBuffer() const {
// See the comment on |mString|'s declaration.
return nsStringBuffer::FromData(mString);
}
/**
* 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:31;
uint32_t mIsStatic:1;
uint32_t mHash;
/**
* WARNING! There is an invisible constraint on |mString|: the chars it
* points to must belong to an nsStringBuffer. This is so that the
* nsStringBuffer::FromData() calls above are valid.
*/
char16_t* mString;
%}
};
%{C++
/*
* The four forms of NS_Atomize (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.
*/
/**
* Find an atom that matches the given UTF-8 string.
* The string is assumed to be zero terminated. Never returns null.
*/
extern already_AddRefed<nsIAtom> NS_Atomize(const char* aUTF8String);
/**
* Find an atom that matches the given UTF-8 string. Never returns null.
*/
extern already_AddRefed<nsIAtom> NS_Atomize(const nsACString& aUTF8String);
/**
* Find an atom that matches the given UTF-16 string.
* The string is assumed to be zero terminated. Never returns null.
*/
extern already_AddRefed<nsIAtom> NS_Atomize(const char16_t* aUTF16String);
/**
* Find an atom that matches the given UTF-16 string. Never returns null.
*/
extern already_AddRefed<nsIAtom> NS_Atomize(const nsAString& 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:
explicit nsAtomString(nsIAtom* aAtom)
{
aAtom->ToString(*this);
}
};
class nsAtomCString : public nsCString
{
public:
explicit nsAtomCString(nsIAtom* aAtom)
{
aAtom->ToUTF8String(*this);
}
};
class nsDependentAtomString : public nsDependentString
{
public:
explicit nsDependentAtomString(nsIAtom* aAtom)
: nsDependentString(aAtom->GetUTF16String(), aAtom->GetLength())
{
}
};
%}