Bug 669410 - Add PrefixSet datastructure for SafeBrowsing. r=dcamp
This commit is contained in:
Gian-Carlo Pascutto
207
toolkit/components/url-classifier/nsUrlClassifierPrefixSet.cpp
Normal file
207
toolkit/components/url-classifier/nsUrlClassifierPrefixSet.cpp
Normal file
@@ -0,0 +1,207 @@
|
||||
//* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
|
||||
/* vim: set ts=2 et sw=2 tw=80: */
|
||||
/* ***** 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 Url Classifier code
|
||||
*
|
||||
* The Initial Developer of the Original Code is
|
||||
* the Mozilla Foundation.
|
||||
* Portions created by the Initial Developer are Copyright (C) 2011
|
||||
* the Initial Developer. All Rights Reserved.
|
||||
*
|
||||
* Contributor(s):
|
||||
* Gian-Carlo Pascutto <gpascutto@mozilla.com>
|
||||
* Mehdi Mulani <mars.martian+bugmail@gmail.com>
|
||||
*
|
||||
* Alternatively, the contents of this file may be used under the terms of
|
||||
* either 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 ***** */
|
||||
|
||||
#include "nsAutoPtr.h"
|
||||
#include "nsCOMPtr.h"
|
||||
#include "nsTArray.h"
|
||||
#include "nsUrlClassifierPrefixSet.h"
|
||||
#include "nsIUrlClassifierPrefixSet.h"
|
||||
#include "nsToolkitCompsCID.h"
|
||||
#include "nsTArray.h"
|
||||
#include "nsThreadUtils.h"
|
||||
#include "mozilla/Mutex.h"
|
||||
#include "prlog.h"
|
||||
|
||||
// NSPR_LOG_MODULES=UrlClassifierPrefixSet:5
|
||||
#if defined(PR_LOGGING)
|
||||
static const PRLogModuleInfo *gUrlClassifierPrefixSetLog = nsnull;
|
||||
#define LOG(args) PR_LOG(gUrlClassifierPrefixSetLog, PR_LOG_DEBUG, args)
|
||||
#define LOG_ENABLED() PR_LOG_TEST(gUrlClassifierPrefixSetLog, 4)
|
||||
#else
|
||||
#define LOG(args)
|
||||
#define LOG_ENABLED() (PR_FALSE)
|
||||
#endif
|
||||
|
||||
NS_IMPL_THREADSAFE_ISUPPORTS1(nsUrlClassifierPrefixSet, nsIUrlClassifierPrefixSet);
|
||||
|
||||
nsUrlClassifierPrefixSet::nsUrlClassifierPrefixSet()
|
||||
: mHasPrefixes(PR_FALSE)
|
||||
{
|
||||
#if defined(PR_LOGGING)
|
||||
if (!gUrlClassifierPrefixSetLog)
|
||||
gUrlClassifierPrefixSetLog = PR_NewLogModule("UrlClassifierPrefixSet");
|
||||
#endif
|
||||
LOG(("Instantiating PrefixSet"));
|
||||
}
|
||||
|
||||
nsresult
|
||||
nsUrlClassifierPrefixSet::SetPrefixes(const PRUint32 * aArray, PRUint32 aLength)
|
||||
{
|
||||
if (mHasPrefixes) {
|
||||
mDeltas.Clear();
|
||||
mIndexPrefixes.Clear();
|
||||
mIndexStarts.Clear();
|
||||
mHasPrefixes = PR_FALSE;
|
||||
}
|
||||
if (aLength > 0) {
|
||||
// Ensure they are sorted before adding
|
||||
nsTArray<PRUint32> prefixes;
|
||||
prefixes.AppendElements(aArray, aLength);
|
||||
prefixes.Sort();
|
||||
AddPrefixes(prefixes.Elements(), prefixes.Length());
|
||||
}
|
||||
|
||||
return NS_OK;
|
||||
}
|
||||
|
||||
nsresult
|
||||
nsUrlClassifierPrefixSet::AddPrefixes(const PRUint32 * prefixes, PRUint32 aLength)
|
||||
{
|
||||
if (aLength == 0) {
|
||||
return NS_OK;
|
||||
}
|
||||
|
||||
mIndexPrefixes.AppendElement(prefixes[0]);
|
||||
mIndexStarts.AppendElement(mDeltas.Length());
|
||||
|
||||
PRUint32 numOfDeltas = 0;
|
||||
PRUint32 currentItem = prefixes[0];
|
||||
for (PRUint32 i = 1; i < aLength; i++) {
|
||||
if ((numOfDeltas >= DELTAS_LIMIT) ||
|
||||
(prefixes[i] - currentItem >= MAX_INDEX_DIFF)) {
|
||||
mIndexStarts.AppendElement(mDeltas.Length());
|
||||
mIndexPrefixes.AppendElement(prefixes[i]);
|
||||
numOfDeltas = 0;
|
||||
} else {
|
||||
PRUint16 delta = prefixes[i] - currentItem;
|
||||
mDeltas.AppendElement(delta);
|
||||
numOfDeltas++;
|
||||
}
|
||||
currentItem = prefixes[i];
|
||||
}
|
||||
|
||||
mIndexPrefixes.Compact();
|
||||
mIndexStarts.Compact();
|
||||
mDeltas.Compact();
|
||||
|
||||
LOG(("Total number of indices: %d", mIndexPrefixes.Length()));
|
||||
LOG(("Total number of deltas: %d", mDeltas.Length()));
|
||||
|
||||
mHasPrefixes = PR_TRUE;
|
||||
|
||||
return NS_OK;
|
||||
}
|
||||
|
||||
PRUint32 nsUrlClassifierPrefixSet::BinSearch(PRUint32 start,
|
||||
PRUint32 end,
|
||||
PRUint32 target)
|
||||
{
|
||||
while (start != end && end >= start) {
|
||||
int i = start + ((end - start) >> 1);
|
||||
int value = mIndexPrefixes[i];
|
||||
if (value < target) {
|
||||
start = i + 1;
|
||||
} else if (value > target) {
|
||||
end = i - 1;
|
||||
} else {
|
||||
return i;
|
||||
}
|
||||
}
|
||||
return end;
|
||||
}
|
||||
|
||||
nsresult
|
||||
nsUrlClassifierPrefixSet::Contains(PRUint32 aPrefix, PRBool * aFound)
|
||||
{
|
||||
*aFound = PR_FALSE;
|
||||
|
||||
if (!mHasPrefixes) {
|
||||
return NS_OK;
|
||||
}
|
||||
|
||||
PRUint32 target = aPrefix;
|
||||
|
||||
// We want to do a "Price is Right" binary search, that is, we want to find
|
||||
// the index of the value either equal to the target or the closest value
|
||||
// that is less than the target.
|
||||
//
|
||||
if (target < mIndexPrefixes[0]) {
|
||||
return NS_OK;
|
||||
}
|
||||
|
||||
// |binsearch| does not necessarily return the correct index (when the
|
||||
// target is not found) but rather it returns an index at least one away
|
||||
// from the correct index.
|
||||
// Because of this, we need to check if the target lies before the beginning
|
||||
// of the indices.
|
||||
|
||||
int i = BinSearch(0, mIndexPrefixes.Length() - 1, target);
|
||||
if (mIndexPrefixes[i] > target && i > 0) {
|
||||
i--;
|
||||
}
|
||||
|
||||
// Now search through the deltas for the target.
|
||||
PRUint32 diff = target - mIndexPrefixes[i];
|
||||
PRUint32 deltaIndex = mIndexStarts[i];
|
||||
PRUint32 end = (i + 1 < mIndexStarts.Length()) ? mIndexStarts[i+1]
|
||||
: mDeltas.Length();
|
||||
while (diff > 0 && deltaIndex < end) {
|
||||
diff -= mDeltas[deltaIndex];
|
||||
deltaIndex++;
|
||||
}
|
||||
|
||||
if (diff == 0) {
|
||||
*aFound = PR_TRUE;
|
||||
}
|
||||
|
||||
return NS_OK;
|
||||
}
|
||||
|
||||
nsresult
|
||||
nsUrlClassifierPrefixSet::EstimateSize(PRUint32 * aSize)
|
||||
{
|
||||
*aSize = sizeof(PRBool);
|
||||
if (mHasPrefixes) {
|
||||
*aSize += sizeof(PRUint16) * mDeltas.Length();
|
||||
*aSize += sizeof(PRUint32) * mIndexPrefixes.Length();
|
||||
*aSize += sizeof(PRUint32) * mIndexStarts.Length();
|
||||
}
|
||||
return NS_OK;
|
||||
}
|
||||
Reference in New Issue
Block a user