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Bug 1542744 - P1. Remove calculating checksum for mIndexDelta array. r=gcp

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The checksum calculating code is used to find the root cause of a crash
bug during update(Bug 1362761). Since the algorithm will be update in
these series of patches, we don't need to keep it.

Differential Revision: https://phabricator.services.mozilla.com/D26667
This commit is contained in:
dlee
2019-05-08 08:35:06 +00:00
parent a961c2b018
commit be3ab07d04
2 changed files with 1 additions and 34 deletions
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34
toolkit/components/url-classifier/nsUrlClassifierPrefixSet.cpp
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@@ -6,7 +6,6 @@
#include "nsUrlClassifierPrefixSet.h"
#include "nsIUrlClassifierPrefixSet.h"
#include "crc32c.h"
#include "nsCOMPtr.h"
#include "nsDebug.h"
#include "nsPrintfCString.h"
@@ -35,22 +34,9 @@ static LazyLogModule gUrlClassifierPrefixSetLog("UrlClassifierPrefixSet");
NS_IMPL_ISUPPORTS(nsUrlClassifierPrefixSet, nsIUrlClassifierPrefixSet,
nsIMemoryReporter)
template <typename T>
static void CalculateTArrayChecksum(const nsTArray<T>& aArray,
uint32_t* outChecksum) {
*outChecksum = ~0;
for (size_t i = 0; i < aArray.Length(); i++) {
const T& element = aArray[i];
const void* pointer = &element;
*outChecksum = ComputeCrc32c(
*outChecksum, reinterpret_cast<const uint8_t*>(pointer), sizeof(void*));
}
}
nsUrlClassifierPrefixSet::nsUrlClassifierPrefixSet()
: mLock("nsUrlClassifierPrefixSet.mLock"),
mIndexDeltasChecksum(~0),
mTotalPrefixes(0) {}
NS_IMETHODIMP
@@ -72,7 +58,6 @@ nsUrlClassifierPrefixSet::~nsUrlClassifierPrefixSet() {
void nsUrlClassifierPrefixSet::Clear() {
LOG(("[%s] Clearing PrefixSet", mName.get()));
mIndexDeltas.Clear();
mIndexDeltasChecksum = ~0;
mIndexPrefixes.Clear();
mTotalPrefixes = 0;
}
@@ -146,15 +131,11 @@ nsresult nsUrlClassifierPrefixSet::MakePrefixSet(const uint32_t* aPrefixes,
mIndexDeltas.LastElement().Compact();
// The hdr pointer of the last element of nsTArray may change after calling
// mIndexDeltas.LastElement().Compact(), so calculate checksum after the call.
CalculateTArrayChecksum(mIndexDeltas, &mIndexDeltasChecksum);
mIndexDeltas.Compact();
mIndexPrefixes.Compact();
MOZ_ASSERT(mIndexPrefixes.Length() == mIndexDeltas.Length());
LOG(("Total number of indices: %d (crc=%u)", aLength, mIndexDeltasChecksum));
LOG(("Total number of indices: %d", aLength));
LOG(("Total number of deltas: %d", totalDeltas));
LOG(("Total number of delta chunks: %zu", mIndexDeltas.Length()));
@@ -443,19 +424,6 @@ nsresult nsUrlClassifierPrefixSet::WritePrefixes(
mCanary.Check();
// In Bug 1362761, crashes happened while reading mIndexDeltas[i].
// We suspect that this is due to memory corruption so to test this
// hypothesis, we will crash the browser. Once we have established
// memory corruption as the root cause, we can attempt to gracefully
// handle this.
uint32_t checksum;
CalculateTArrayChecksum(mIndexDeltas, &checksum);
if (checksum != mIndexDeltasChecksum) {
LOG(("[%s] The contents of mIndexDeltas doesn't match the checksum!",
mName.get()));
MOZ_CRASH("Memory corruption detected in mIndexDeltas.");
}
uint32_t written;
uint32_t writelen = sizeof(uint32_t);
const uint32_t magic = PREFIXSET_VERSION_MAGIC;