gecko-dev/xpcom/ds/nsAtomTable.cpp
1999-02-06 03:56:36 +00:00

155 lines
4.1 KiB
C++

/* -*- 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 1.0 (the "NPL"); you may not use this file except in
* compliance with the NPL. You may obtain a copy of the NPL at
* http://www.mozilla.org/NPL/
*
* Software distributed under the NPL is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
* for the specific language governing rights and limitations under the
* NPL.
*
* The Initial Developer of this code under the NPL is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All Rights
* Reserved.
*/
#include "nsIAtom.h"
#include "nsString.h"
#include "nsCRT.h"
#include "plhash.h"
#include "nsISizeOfHandler.h"
/**
* The shared hash table for atom lookups.
*/
static nsrefcnt gAtoms;
static struct PLHashTable* gAtomHashTable;
class AtomImpl : public nsIAtom {
public:
AtomImpl();
~AtomImpl();
NS_DECL_ISUPPORTS
void* operator new(size_t size, const PRUnichar* us, PRInt32 uslen);
virtual void ToString(nsString& aBuf) const;
virtual const PRUnichar* GetUnicode() const;
NS_IMETHOD SizeOf(nsISizeOfHandler* aHandler) const;
// Actually more; 0 terminated. This slot is reserved for the
// terminating zero.
PRUnichar mString[1];
};
AtomImpl::AtomImpl()
{
NS_INIT_REFCNT();
// Every live atom holds a reference on the atom hashtable
gAtoms++;
}
AtomImpl::~AtomImpl()
{
NS_PRECONDITION(nsnull != gAtomHashTable, "null atom hashtable");
if (nsnull != gAtomHashTable) {
PL_HashTableRemove(gAtomHashTable, mString);
nsrefcnt cnt = --gAtoms;
if (0 == cnt) {
// When the last atom is destroyed, the atom arena is destroyed
NS_ASSERTION(0 == gAtomHashTable->nentries, "bad atom table");
PL_HashTableDestroy(gAtomHashTable);
gAtomHashTable = nsnull;
}
}
}
static NS_DEFINE_IID(kIAtomIID, NS_IATOM_IID);
NS_IMPL_ISUPPORTS(AtomImpl, kIAtomIID);
void* AtomImpl::operator new(size_t size, const PRUnichar* us, PRInt32 uslen)
{
size = size + uslen * sizeof(PRUnichar);
AtomImpl* ii = (AtomImpl*) new char[size];
nsCRT::memcpy(ii->mString, us, uslen * sizeof(PRUnichar));
ii->mString[uslen] = 0;
return ii;
}
void AtomImpl::ToString(nsString& aBuf) const
{
aBuf.SetLength(0);
aBuf.Append(mString, nsCRT::strlen(mString));
}
const PRUnichar* AtomImpl::GetUnicode() const
{
return mString;
}
NS_IMETHODIMP
AtomImpl::SizeOf(nsISizeOfHandler* aHandler) const
{
aHandler->Add(sizeof(*this) + nsCRT::strlen(mString) * sizeof(PRUnichar));
return NS_OK;
}
//----------------------------------------------------------------------
static PLHashNumber HashKey(const PRUnichar* k)
{
return (PLHashNumber) nsCRT::HashValue(k);
}
static PRIntn CompareKeys(const PRUnichar* k1, const PRUnichar* k2)
{
return nsCRT::strcmp(k1, k2) == 0;
}
NS_BASE nsIAtom* NS_NewAtom(const char* isolatin1)
{
nsAutoString tmp(isolatin1);
return NS_NewAtom(tmp.GetUnicode());
}
NS_BASE nsIAtom* NS_NewAtom(const nsString& aString)
{
return NS_NewAtom(aString.GetUnicode());
}
NS_BASE nsIAtom* NS_NewAtom(const PRUnichar* us)
{
if (nsnull == gAtomHashTable) {
gAtomHashTable = PL_NewHashTable(8, (PLHashFunction) HashKey,
(PLHashComparator) CompareKeys,
(PLHashComparator) nsnull,
nsnull, nsnull);
}
PRUint32 uslen;
PRUint32 hashCode = nsCRT::HashValue(us, &uslen);
PLHashEntry** hep = PL_HashTableRawLookup(gAtomHashTable, hashCode, us);
PLHashEntry* he = *hep;
if (nsnull != he) {
nsIAtom* id = (nsIAtom*) he->value;
NS_ADDREF(id);
return id;
}
AtomImpl* id = new(us, uslen) AtomImpl();
PL_HashTableRawAdd(gAtomHashTable, hep, hashCode, id->mString, id);
NS_ADDREF(id);
return id;
}
NS_BASE nsrefcnt NS_GetNumberOfAtoms(void)
{
if (nsnull != gAtomHashTable) {
NS_PRECONDITION(nsrefcnt(gAtomHashTable->nentries) == gAtoms, "bad atom table");
}
return gAtoms;
}