gecko-dev/xpcom/base/nsUUIDGenerator.cpp

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4.3 KiB
C++

/* -*- Mode: C++; tab-width: 50; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla 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/MPL/
*
* 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.org code.
*
* The Initial Developer of the Original Code is
* mozilla.org
* Portions created by the Initial Developer are Copyright (C) 2005
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Vladimir Vukicevic <vladimir@pobox.com> (original author)
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifdef XP_WIN
#include <windows.h>
#include <objbase.h>
#else
#include <stdlib.h>
#endif
#include <nsMemory.h>
#include "nsUUIDGenerator.h"
#include "prrng.h"
NS_IMPL_ISUPPORTS1(nsUUIDGenerator, nsIUUIDGenerator)
nsUUIDGenerator::nsUUIDGenerator()
: mInitialized(PR_FALSE)
{
}
nsresult
nsUUIDGenerator::Init()
{
#ifndef XP_WIN
/* initialize random number generator using NSPR random noise */
unsigned int seed;
PRSize bytes = 0;
while (bytes < sizeof(seed)) {
PRSize nbytes = PR_GetRandomNoise(((unsigned char *)&seed)+bytes,
sizeof(seed)-bytes);
if (nbytes == 0) {
return NS_ERROR_FAILURE;
}
bytes += nbytes;
}
initstate(seed, mState, sizeof(mState));
mRBytes = 4;
#ifdef RAND_MAX
if ((unsigned long) RAND_MAX < (unsigned long)0xffffffff)
mRBytes = 3;
if ((unsigned long) RAND_MAX < (unsigned long)0x00ffffff)
mRBytes = 2;
if ((unsigned long) RAND_MAX < (unsigned long)0x0000ffff)
mRBytes = 1;
if ((unsigned long) RAND_MAX < (unsigned long)0x000000ff)
return NS_ERROR_FAILURE;
#endif
#endif /* non XP_WIN */
mInitialized = PR_TRUE;
return NS_OK;
}
NS_IMETHODIMP
nsUUIDGenerator::GenerateUUID(nsID** ret)
{
nsID *id = NS_STATIC_CAST(nsID*, NS_Alloc(sizeof(nsID)));
if (id == nsnull)
return NS_ERROR_OUT_OF_MEMORY;
nsresult rv = GenerateUUIDInPlace(id);
if (NS_FAILED(rv)) {
NS_Free(id);
return rv;
}
*ret = id;
return rv;
}
NS_IMETHODIMP
nsUUIDGenerator::GenerateUUIDInPlace(nsID* id)
{
if (!mInitialized) {
nsresult rv = Init();
if (NS_FAILED(rv))
return rv;
}
#ifdef XP_WIN
HRESULT hr = CoCreateGuid((GUID*)id);
if (NS_FAILED(hr))
return NS_ERROR_FAILURE;
#else /* non-windows; generate randomness using random(). */
PRSize bytesLeft = sizeof(nsID);
while (bytesLeft > 0) {
long rval = random();
PRUint8 *src = (PRUint8*)&rval;
#ifdef IS_LITTLE_ENDIAN
src += sizeof(rval) - mRBytes;
#endif
PRUint8 *dst = ((PRUint8*) id) + (sizeof(nsID) - bytesLeft);
PRSize toWrite = (bytesLeft < mRBytes ? bytesLeft : mRBytes);
for (PRSize i = 0; i < toWrite; i++)
dst[i] = src[i];
bytesLeft -= toWrite;
}
/* Put in the version */
id->m2 &= 0x0fff;
id->m2 |= 0x4000;
/* Put in the variant */
id->m3[0] &= 0x3f;
id->m3[0] |= 0x80;
#endif
return NS_OK;
}