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/* vim:set ts=4 sw=2 sts=2 et cin: */
/* 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 "HostRecordQueue.h"
#include "mozilla/Telemetry.h"
#include "nsQueryObject.h"
namespace mozilla {
namespace net {
void HostRecordQueue::InsertRecord(nsHostRecord* aRec,
nsIDNSService::DNSFlags aFlags,
const MutexAutoLock& aProofOfLock) {
if (aRec->isInList()) {
MOZ_DIAGNOSTIC_ASSERT(!mEvictionQ.contains(aRec),
"Already in eviction queue");
MOZ_DIAGNOSTIC_ASSERT(!mHighQ.contains(aRec), "Already in high queue");
MOZ_DIAGNOSTIC_ASSERT(!mMediumQ.contains(aRec), "Already in med queue");
MOZ_DIAGNOSTIC_ASSERT(!mLowQ.contains(aRec), "Already in low queue");
MOZ_DIAGNOSTIC_ASSERT(false, "Already on some other queue?");
}
switch (AddrHostRecord::GetPriority(aFlags)) {
case AddrHostRecord::DNS_PRIORITY_HIGH:
mHighQ.insertBack(aRec);
break;
case AddrHostRecord::DNS_PRIORITY_MEDIUM:
mMediumQ.insertBack(aRec);
break;
case AddrHostRecord::DNS_PRIORITY_LOW:
mLowQ.insertBack(aRec);
break;
}
mPendingCount++;
}
void HostRecordQueue::AddToEvictionQ(
nsHostRecord* aRec, uint32_t aMaxCacheEntries,
nsRefPtrHashtable<nsGenericHashKey<nsHostKey>, nsHostRecord>& aDB,
const MutexAutoLock& aProofOfLock) {
if (aRec->isInList()) {
bool inEvictionQ = mEvictionQ.contains(aRec);
MOZ_DIAGNOSTIC_ASSERT(!inEvictionQ, "Already in eviction queue");
bool inHighQ = mHighQ.contains(aRec);
MOZ_DIAGNOSTIC_ASSERT(!inHighQ, "Already in high queue");
bool inMediumQ = mMediumQ.contains(aRec);
MOZ_DIAGNOSTIC_ASSERT(!inMediumQ, "Already in med queue");
bool inLowQ = mLowQ.contains(aRec);
MOZ_DIAGNOSTIC_ASSERT(!inLowQ, "Already in low queue");
MOZ_DIAGNOSTIC_ASSERT(false, "Already on some other queue?");
// Bug 1678117 - it's not clear why this can happen, but let's fix it
// for release users.
aRec->remove();
if (inEvictionQ) {
MOZ_DIAGNOSTIC_ASSERT(mEvictionQSize > 0);
mEvictionQSize--;
} else if (inHighQ || inMediumQ || inLowQ) {
MOZ_DIAGNOSTIC_ASSERT(mPendingCount > 0);
mPendingCount--;
}
}
mEvictionQ.insertBack(aRec);
if (mEvictionQSize < aMaxCacheEntries) {
mEvictionQSize++;
} else {
// remove first element on mEvictionQ
RefPtr<nsHostRecord> head = mEvictionQ.popFirst();
aDB.Remove(*static_cast<nsHostKey*>(head.get()));
if (!head->negative) {
// record the age of the entry upon eviction.
TimeDuration age = TimeStamp::NowLoRes() - head->mValidStart;
if (aRec->IsAddrRecord()) {
Telemetry::Accumulate(Telemetry::DNS_CLEANUP_AGE,
static_cast<uint32_t>(age.ToSeconds() / 60));
} else {
Telemetry::Accumulate(Telemetry::DNS_BY_TYPE_CLEANUP_AGE,
static_cast<uint32_t>(age.ToSeconds() / 60));
}
if (head->CheckExpiration(TimeStamp::Now()) !=
nsHostRecord::EXP_EXPIRED) {
if (aRec->IsAddrRecord()) {
Telemetry::Accumulate(Telemetry::DNS_PREMATURE_EVICTION,
static_cast<uint32_t>(age.ToSeconds() / 60));
} else {
Telemetry::Accumulate(Telemetry::DNS_BY_TYPE_PREMATURE_EVICTION,
static_cast<uint32_t>(age.ToSeconds() / 60));
}
}
}
}
}
void HostRecordQueue::MaybeRenewHostRecord(nsHostRecord* aRec,
const MutexAutoLock& aProofOfLock) {
if (!aRec->isInList()) {
return;
}
bool inEvictionQ = mEvictionQ.contains(aRec);
MOZ_DIAGNOSTIC_ASSERT(inEvictionQ, "Should be in eviction queue");
bool inHighQ = mHighQ.contains(aRec);
MOZ_DIAGNOSTIC_ASSERT(!inHighQ, "Already in high queue");
bool inMediumQ = mMediumQ.contains(aRec);
MOZ_DIAGNOSTIC_ASSERT(!inMediumQ, "Already in med queue");
bool inLowQ = mLowQ.contains(aRec);
MOZ_DIAGNOSTIC_ASSERT(!inLowQ, "Already in low queue");
// we're already on the eviction queue. This is a renewal
aRec->remove();
if (inEvictionQ) {
MOZ_DIAGNOSTIC_ASSERT(mEvictionQSize > 0);
mEvictionQSize--;
} else if (inHighQ || inMediumQ || inLowQ) {
MOZ_DIAGNOSTIC_ASSERT(mPendingCount > 0);
mPendingCount--;
}
}
void HostRecordQueue::FlushEvictionQ(
nsRefPtrHashtable<nsGenericHashKey<nsHostKey>, nsHostRecord>& aDB,
const MutexAutoLock& aProofOfLock) {
mEvictionQSize = 0;
// Clear the evictionQ and remove all its corresponding entries from
// the cache first
if (!mEvictionQ.isEmpty()) {
for (const RefPtr<nsHostRecord>& rec : mEvictionQ) {
rec->Cancel();
aDB.Remove(*static_cast<nsHostKey*>(rec));
}
mEvictionQ.clear();
}
}
void HostRecordQueue::MaybeRemoveFromQ(nsHostRecord* aRec,
const MutexAutoLock& aProofOfLock) {
if (!aRec->isInList()) {
return;
}
if (mHighQ.contains(aRec) || mMediumQ.contains(aRec) ||
mLowQ.contains(aRec)) {
mPendingCount--;
} else if (mEvictionQ.contains(aRec)) {
mEvictionQSize--;
} else {
MOZ_ASSERT(false, "record is in other queue");
}
aRec->remove();
}
void HostRecordQueue::MoveToAnotherPendingQ(nsHostRecord* aRec,
nsIDNSService::DNSFlags aFlags,
const MutexAutoLock& aProofOfLock) {
if (!(mHighQ.contains(aRec) || mMediumQ.contains(aRec) ||
mLowQ.contains(aRec))) {
MOZ_ASSERT(false, "record is not in the pending queue");
return;
}
aRec->remove();
InsertRecord(aRec, aFlags, aProofOfLock);
}
already_AddRefed<AddrHostRecord> HostRecordQueue::Dequeue(
bool aHighQOnly, const MutexAutoLock& aProofOfLock) {
RefPtr<nsHostRecord> rec;
if (!mHighQ.isEmpty()) {
rec = mHighQ.popFirst();
} else if (!mMediumQ.isEmpty() && !aHighQOnly) {
rec = mMediumQ.popFirst();
} else if (!mLowQ.isEmpty() && !aHighQOnly) {
rec = mLowQ.popFirst();
}
if (rec) {
MOZ_ASSERT(rec->IsAddrRecord());
mPendingCount--;
RefPtr<AddrHostRecord> addrRec = do_QueryObject(rec);
return addrRec.forget();
}
return nullptr;
}
void HostRecordQueue::ClearAll(
const std::function<void(nsHostRecord*)>& aCallback,
const MutexAutoLock& aProofOfLock) {
mPendingCount = 0;
auto clearPendingQ = [&](LinkedList<RefPtr<nsHostRecord>>& aPendingQ) {
if (aPendingQ.isEmpty()) {
return;
}
// loop through pending queue, erroring out pending lookups.
for (const RefPtr<nsHostRecord>& rec : aPendingQ) {
rec->Cancel();
aCallback(rec);
}
aPendingQ.clear();
};
clearPendingQ(mHighQ);
clearPendingQ(mMediumQ);
clearPendingQ(mLowQ);
mEvictionQSize = 0;
if (!mEvictionQ.isEmpty()) {
for (const RefPtr<nsHostRecord>& rec : mEvictionQ) {
rec->Cancel();
}
}
mEvictionQ.clear();
}
} // namespace net
} // namespace mozilla
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