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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 "nsUrlClassifierPrefixSet.h"
#include "nsIUrlClassifierPrefixSet.h"
#include "nsCOMPtr.h"
#include "nsDebug.h"
#include "nsIInputStream.h"
#include "nsIOutputStream.h"
#include "nsPrintfCString.h"
#include "nsTArray.h"
#include "nsString.h"
#include "nsTArray.h"
#include "nsThreadUtils.h"
#include "nsNetUtil.h"
#include "mozilla/StaticPrefs_browser.h"
#include "mozilla/Telemetry.h"
#include "mozilla/Logging.h"
#include "mozilla/Unused.h"
#include <algorithm>
using namespace mozilla;
// MOZ_LOG=UrlClassifierPrefixSet:5
static LazyLogModule gUrlClassifierPrefixSetLog("UrlClassifierPrefixSet");
#define LOG(args) \
MOZ_LOG(gUrlClassifierPrefixSetLog, mozilla::LogLevel::Debug, args)
#define LOG_ENABLED() \
MOZ_LOG_TEST(gUrlClassifierPrefixSetLog, mozilla::LogLevel::Debug)
NS_IMPL_ISUPPORTS(nsUrlClassifierPrefixSet, nsIUrlClassifierPrefixSet)
nsUrlClassifierPrefixSet::nsUrlClassifierPrefixSet()
: mLock("nsUrlClassifierPrefixSet.mLock"), mTotalPrefixes(0) {}
NS_IMETHODIMP
nsUrlClassifierPrefixSet::Init(const nsACString& aName) {
mName = aName;
return NS_OK;
}
nsUrlClassifierPrefixSet::~nsUrlClassifierPrefixSet() {}
void nsUrlClassifierPrefixSet::Clear() {
LOG(("[%s] Clearing PrefixSet", mName.get()));
mIndexDeltas.Clear();
mIndexPrefixes.Clear();
mTotalPrefixes = 0;
}
NS_IMETHODIMP
nsUrlClassifierPrefixSet::SetPrefixes(const uint32_t* aArray,
uint32_t aLength) {
MutexAutoLock lock(mLock);
nsresult rv = NS_OK;
Clear();
if (aLength > 0) {
rv = MakePrefixSet(aArray, aLength);
if (NS_WARN_IF(NS_FAILED(rv))) {
Clear(); // clear out any leftovers
}
}
MOZ_ASSERT_IF(mIndexDeltas.IsEmpty(),
mIndexPrefixes.Length() == mTotalPrefixes);
MOZ_ASSERT_IF(!mIndexDeltas.IsEmpty(),
mIndexPrefixes.Length() == mIndexDeltas.Length());
return rv;
}
nsresult nsUrlClassifierPrefixSet::MakePrefixSet(const uint32_t* aPrefixes,
uint32_t aLength) {
mLock.AssertCurrentThreadOwns();
MOZ_ASSERT(aPrefixes);
MOZ_ASSERT(aLength > 0);
#ifdef DEBUG
for (uint32_t i = 1; i < aLength; i++) {
MOZ_ASSERT(aPrefixes[i] >= aPrefixes[i - 1]);
}
#endif
uint32_t totalDeltas = 0;
// Request one memory space to store all the prefixes may lead to
// memory allocation failure on certain platforms(See Bug 1046038).
// So if required size to store all the prefixes exceeds defined
// threshold(512k), we divide prefixes into delta chunks instead. Note that
// the potential overhead of this approach is that it may reuqire more memory
// compared to store all prefixes in one array because of jemalloc's
// implementation.
if (aLength * sizeof(uint32_t) <
StaticPrefs::browser_safebrowsing_prefixset_max_array_size()) {
// Not over the threshold, store all prefixes into mIndexPrefixes.
// mIndexDeltas is empty in this case.
mIndexPrefixes.SetCapacity(aLength);
for (uint32_t i = 0; i < aLength; i++) {
mIndexPrefixes.AppendElement(aPrefixes[i]);
}
} else {
// Apply delta algorithm to split prefixes into smaller delta chunk.
// We estimate the capacity of mIndexPrefixes & mIndexDeltas by assuming
// each element in mIndexDeltas stores DELTAS_LIMITS deltas, so the
// number of indexed prefixes is round up of
// TotalPrefixes / (DELTA_LIMIT + 1)
// The estimation only works when the number of prefixes are over a
// certain limit, which means, arrays in mIndexDeltas are always full.
uint32_t estimateCapacity =
(aLength + (DELTAS_LIMIT + 1) - 1) / (DELTAS_LIMIT + 1);
mIndexPrefixes.SetCapacity(estimateCapacity);
mIndexDeltas.SetCapacity(estimateCapacity);
mIndexPrefixes.AppendElement(aPrefixes[0]);
mIndexDeltas.AppendElement();
mIndexDeltas.LastElement().SetCapacity(DELTAS_LIMIT);
uint32_t numOfDeltas = 0;
uint32_t previousItem = aPrefixes[0];
for (uint32_t i = 1; i < aLength; i++) {
if ((numOfDeltas >= DELTAS_LIMIT) ||
(aPrefixes[i] - previousItem >= MAX_INDEX_DIFF)) {
// Compact the previous element.
// Note there is always at least one element when we get here,
// because we created the first element before the loop.
mIndexDeltas.LastElement().Compact();
if (!mIndexDeltas.AppendElement(fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
mIndexDeltas.LastElement().SetCapacity(DELTAS_LIMIT);
if (!mIndexPrefixes.AppendElement(aPrefixes[i], fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
numOfDeltas = 0;
} else {
uint16_t delta = aPrefixes[i] - previousItem;
if (!mIndexDeltas.LastElement().AppendElement(delta, fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
numOfDeltas++;
totalDeltas++;
}
previousItem = aPrefixes[i];
}
mIndexDeltas.LastElement().Compact();
mIndexDeltas.Compact();
mIndexPrefixes.Compact();
MOZ_ASSERT(mIndexPrefixes.Length() == mIndexDeltas.Length());
}
if (totalDeltas == 0) {
// We have to clear mIndexDeltas here because it is still possible
// that the delta generation algorithm produces no deltas at all. When that
// happens, mIndexDeltas is not empty, which conflicts with the assumption
// that when there is no delta, mIndexDeltas is empty.
mIndexDeltas.Clear();
}
mTotalPrefixes = aLength;
LOG(("Total number of indices: %d", aLength));
LOG(("Total number of deltas: %d", totalDeltas));
LOG(("Total number of delta chunks: %zu", mIndexDeltas.Length()));
return NS_OK;
}
nsresult nsUrlClassifierPrefixSet::GetPrefixesNative(
FallibleTArray<uint32_t>& outArray) {
MutexAutoLock lock(mLock);
if (!outArray.SetLength(mTotalPrefixes, fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
uint32_t prefixIdxLength = mIndexPrefixes.Length();
uint32_t prefixCnt = 0;
for (uint32_t i = 0; i < prefixIdxLength; i++) {
uint32_t prefix = mIndexPrefixes[i];
if (prefixCnt >= mTotalPrefixes) {
return NS_ERROR_FAILURE;
}
outArray[prefixCnt++] = prefix;
if (mIndexDeltas.IsEmpty()) {
continue;
}
for (uint32_t j = 0; j < mIndexDeltas[i].Length(); j++) {
prefix += mIndexDeltas[i][j];
if (prefixCnt >= mTotalPrefixes) {
return NS_ERROR_FAILURE;
}
outArray[prefixCnt++] = prefix;
}
}
NS_ASSERTION(mTotalPrefixes == prefixCnt, "Lengths are inconsistent");
return NS_OK;
}
NS_IMETHODIMP
nsUrlClassifierPrefixSet::GetPrefixes(uint32_t* aCount, uint32_t** aPrefixes) {
// No need to get mLock here because this function does not directly touch
// the class's data members. (GetPrefixesNative() will get mLock, however.)
NS_ENSURE_ARG_POINTER(aCount);
*aCount = 0;
NS_ENSURE_ARG_POINTER(aPrefixes);
*aPrefixes = nullptr;
FallibleTArray<uint32_t> prefixes;
nsresult rv = GetPrefixesNative(prefixes);
if (NS_FAILED(rv)) {
return rv;
}
uint64_t itemCount = prefixes.Length();
uint32_t* prefixArray =
static_cast<uint32_t*>(moz_xmalloc(itemCount * sizeof(uint32_t)));
memcpy(prefixArray, prefixes.Elements(), sizeof(uint32_t) * itemCount);
*aCount = itemCount;
*aPrefixes = prefixArray;
return NS_OK;
}
uint32_t nsUrlClassifierPrefixSet::BinSearch(uint32_t start, uint32_t end,
uint32_t target) const {
mLock.AssertCurrentThreadOwns();
while (start != end && end >= start) {
uint32_t i = start + ((end - start) >> 1);
uint32_t value = mIndexPrefixes[i];
if (value < target) {
start = i + 1;
} else if (value > target) {
end = i - 1;
} else {
return i;
}
}
return end;
}
NS_IMETHODIMP
nsUrlClassifierPrefixSet::Contains(uint32_t aPrefix, bool* aFound) {
MutexAutoLock lock(mLock);
*aFound = false;
if (IsEmptyInternal()) {
return NS_OK;
}
uint32_t 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.
uint32_t i = BinSearch(0, mIndexPrefixes.Length() - 1, target);
if (mIndexPrefixes[i] > target && i > 0) {
i--;
}
// Now search through the deltas for the target.
uint32_t diff = target - mIndexPrefixes[i];
if (!mIndexDeltas.IsEmpty()) {
uint32_t deltaSize = mIndexDeltas[i].Length();
uint32_t deltaIndex = 0;
while (diff > 0 && deltaIndex < deltaSize) {
diff -= mIndexDeltas[i][deltaIndex];
deltaIndex++;
}
}
if (diff == 0) {
*aFound = true;
}
return NS_OK;
}
size_t nsUrlClassifierPrefixSet::SizeOfIncludingThis(
mozilla::MallocSizeOf aMallocSizeOf) const {
MutexAutoLock lock(mLock);
size_t n = 0;
n += aMallocSizeOf(this);
n += mIndexDeltas.ShallowSizeOfExcludingThis(aMallocSizeOf);
for (uint32_t i = 0; i < mIndexDeltas.Length(); i++) {
n += mIndexDeltas[i].ShallowSizeOfExcludingThis(aMallocSizeOf);
}
n += mIndexPrefixes.ShallowSizeOfExcludingThis(aMallocSizeOf);
return n;
}
bool nsUrlClassifierPrefixSet::IsEmptyInternal() const {
if (mIndexPrefixes.IsEmpty()) {
MOZ_ASSERT(mIndexDeltas.IsEmpty() && mTotalPrefixes == 0,
"If we're empty, there should be no leftovers.");
return true;
}
MOZ_ASSERT(mTotalPrefixes >= mIndexPrefixes.Length());
return false;
}
NS_IMETHODIMP
nsUrlClassifierPrefixSet::IsEmpty(bool* aEmpty) {
MutexAutoLock lock(mLock);
*aEmpty = IsEmptyInternal();
return NS_OK;
}
nsresult nsUrlClassifierPrefixSet::LoadPrefixes(nsCOMPtr<nsIInputStream>& in) {
MutexAutoLock lock(mLock);
mCanary.Check();
Clear();
uint32_t magic;
uint32_t read;
nsresult rv =
in->Read(reinterpret_cast<char*>(&magic), sizeof(uint32_t), &read);
NS_ENSURE_SUCCESS(rv, rv);
NS_ENSURE_TRUE(read == sizeof(uint32_t), NS_ERROR_FAILURE);
if (magic == PREFIXSET_VERSION_MAGIC) {
// Read the number of indexed prefixes
uint32_t indexSize;
rv = in->Read(reinterpret_cast<char*>(&indexSize), sizeof(uint32_t), &read);
NS_ENSURE_SUCCESS(rv, rv);
NS_ENSURE_TRUE(read == sizeof(uint32_t), NS_ERROR_FAILURE);
// Read the number of delta prefixes
uint32_t deltaSize;
rv = in->Read(reinterpret_cast<char*>(&deltaSize), sizeof(uint32_t), &read);
NS_ENSURE_SUCCESS(rv, rv);
NS_ENSURE_TRUE(read == sizeof(uint32_t), NS_ERROR_FAILURE);
if (indexSize == 0) {
LOG(("[%s] Stored PrefixSet is empty!", mName.get()));
return NS_OK;
}
if (!mIndexPrefixes.SetLength(indexSize, fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
mTotalPrefixes = indexSize;
if (deltaSize > (indexSize * DELTAS_LIMIT)) {
return NS_ERROR_FILE_CORRUPTED;
}
// Read index prefixes
uint32_t toRead = indexSize * sizeof(uint32_t);
rv = in->Read(reinterpret_cast<char*>(mIndexPrefixes.Elements()), toRead,
&read);
NS_ENSURE_SUCCESS(rv, rv);
NS_ENSURE_TRUE(read == toRead, NS_ERROR_FAILURE);
if (deltaSize) {
nsTArray<uint32_t> indexStarts;
if (!indexStarts.SetLength(indexSize, fallible) ||
!mIndexDeltas.SetLength(indexSize, fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
// Read index start array to construct mIndexDeltas
rv = in->Read(reinterpret_cast<char*>(indexStarts.Elements()), toRead,
&read);
NS_ENSURE_SUCCESS(rv, rv);
NS_ENSURE_TRUE(read == toRead, NS_ERROR_FAILURE);
if (indexStarts[0] != 0) {
return NS_ERROR_FILE_CORRUPTED;
}
for (uint32_t i = 0; i < indexSize; i++) {
uint32_t numInDelta = i == indexSize - 1
? deltaSize - indexStarts[i]
: indexStarts[i + 1] - indexStarts[i];
if (numInDelta > DELTAS_LIMIT) {
return NS_ERROR_FILE_CORRUPTED;
}
if (numInDelta > 0) {
if (!mIndexDeltas[i].SetLength(numInDelta, fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
mTotalPrefixes += numInDelta;
toRead = numInDelta * sizeof(uint16_t);
rv = in->Read(reinterpret_cast<char*>(mIndexDeltas[i].Elements()),
toRead, &read);
NS_ENSURE_SUCCESS(rv, rv);
NS_ENSURE_TRUE(read == toRead, NS_ERROR_FAILURE);
}
}
} else {
mIndexDeltas.Clear();
}
} else {
LOG(("[%s] Version magic mismatch, not loading", mName.get()));
return NS_ERROR_FILE_CORRUPTED;
}
MOZ_ASSERT_IF(mIndexDeltas.IsEmpty(),
mIndexPrefixes.Length() == mTotalPrefixes);
MOZ_ASSERT_IF(!mIndexDeltas.IsEmpty(),
mIndexPrefixes.Length() == mIndexDeltas.Length());
LOG(("[%s] Loading PrefixSet successful (%u total prefixes)", mName.get(),
mTotalPrefixes));
return NS_OK;
}
uint32_t nsUrlClassifierPrefixSet::CalculatePreallocateSize() const {
uint32_t fileSize = 4 * sizeof(uint32_t);
MOZ_RELEASE_ASSERT(mTotalPrefixes >= mIndexPrefixes.Length());
uint32_t deltas = mTotalPrefixes - mIndexPrefixes.Length();
fileSize += mIndexPrefixes.Length() * sizeof(uint32_t);
if (deltas) {
MOZ_ASSERT(mIndexPrefixes.Length() == mIndexDeltas.Length());
fileSize += mIndexPrefixes.Length() * sizeof(uint32_t);
fileSize += mIndexDeltas.Length() * sizeof(uint32_t);
fileSize += deltas * sizeof(uint16_t);
}
return fileSize;
}
nsresult nsUrlClassifierPrefixSet::WritePrefixes(
nsCOMPtr<nsIOutputStream>& out) const {
MutexAutoLock lock(mLock);
MOZ_ASSERT_IF(mIndexDeltas.IsEmpty(),
mIndexPrefixes.Length() == mTotalPrefixes);
MOZ_ASSERT_IF(!mIndexDeltas.IsEmpty(),
mIndexPrefixes.Length() == mIndexDeltas.Length());
mCanary.Check();
uint32_t written;
uint32_t writelen = sizeof(uint32_t);
const uint32_t magic = PREFIXSET_VERSION_MAGIC;
nsresult rv =
out->Write(reinterpret_cast<const char*>(&magic), writelen, &written);
NS_ENSURE_SUCCESS(rv, rv);
NS_ENSURE_TRUE(written == writelen, NS_ERROR_FAILURE);
const uint32_t indexSize = mIndexPrefixes.Length();
if (mIndexDeltas.IsEmpty()) {
if (NS_WARN_IF(mTotalPrefixes != indexSize)) {
LOG(("[%s] mIndexPrefixes doesn't have the same length as mTotalPrefixes",
mName.get()));
return NS_ERROR_FAILURE;
}
} else {
if (NS_WARN_IF(mIndexDeltas.Length() != indexSize)) {
LOG(("[%s] mIndexPrefixes doesn't have the same length as mIndexDeltas",
mName.get()));
return NS_ERROR_FAILURE;
}
}
uint32_t totalDeltas = 0;
// Store the shape of mIndexDeltas by noting at which "count" of total
// indexes a new subarray starts. This is slightly cumbersome but keeps
// file format compatibility.
// If we ever update the format, we can gain space by storing the delta
// subarray sizes, which fit in bytes.
nsTArray<uint32_t> indexStarts;
if (!mIndexDeltas.IsEmpty()) {
if (!indexStarts.SetCapacity(indexSize + 1, fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
indexStarts.AppendElement(0);
for (uint32_t i = 0; i < indexSize; i++) {
uint32_t deltaLength = mIndexDeltas[i].Length();
totalDeltas += deltaLength;
indexStarts.AppendElement(totalDeltas);
}
indexStarts.RemoveLastElement(); // we don't use the last element
MOZ_ASSERT(indexStarts.Length() == indexSize);
}
rv =
out->Write(reinterpret_cast<const char*>(&indexSize), writelen, &written);
NS_ENSURE_SUCCESS(rv, rv);
NS_ENSURE_TRUE(written == writelen, NS_ERROR_FAILURE);
rv = out->Write(reinterpret_cast<const char*>(&totalDeltas), writelen,
&written);
NS_ENSURE_SUCCESS(rv, rv);
NS_ENSURE_TRUE(written == writelen, NS_ERROR_FAILURE);
writelen = indexSize * sizeof(uint32_t);
rv = out->Write(reinterpret_cast<const char*>(mIndexPrefixes.Elements()),
writelen, &written);
NS_ENSURE_SUCCESS(rv, rv);
NS_ENSURE_TRUE(written == writelen, NS_ERROR_FAILURE);
if (!mIndexDeltas.IsEmpty()) {
MOZ_ASSERT(!indexStarts.IsEmpty() && totalDeltas > 0);
rv = out->Write(reinterpret_cast<const char*>(indexStarts.Elements()),
writelen, &written);
NS_ENSURE_SUCCESS(rv, rv);
NS_ENSURE_TRUE(written == writelen, NS_ERROR_FAILURE);
for (uint32_t i = 0; i < indexSize; i++) {
writelen = mIndexDeltas[i].Length() * sizeof(uint16_t);
rv = out->Write(reinterpret_cast<const char*>(mIndexDeltas[i].Elements()),
writelen, &written);
NS_ENSURE_SUCCESS(rv, rv);
NS_ENSURE_TRUE(written == writelen, NS_ERROR_FAILURE);
}
}
LOG(("[%s] Writing PrefixSet successful", mName.get()));
return NS_OK;
}