Add m-esr52 at 52.6.0

1 files changed, 3810 insertions, 0 deletions

diff --git a/netwerk/cache2/CacheIndex.cpp b/netwerk/cache2/CacheIndex.cpp
new file mode 100644
index 000000000..4525bbe6d
--- /dev/null
+++ b/netwerk/cache2/CacheIndex.cpp
@@ -0,0 +1,3810 @@
+/* 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 "CacheIndex.h"
+
+#include "CacheLog.h"
+#include "CacheFileIOManager.h"
+#include "CacheFileMetadata.h"
+#include "CacheIndexIterator.h"
+#include "CacheIndexContextIterator.h"
+#include "nsThreadUtils.h"
+#include "nsISimpleEnumerator.h"
+#include "nsIDirectoryEnumerator.h"
+#include "nsISizeOf.h"
+#include "nsPrintfCString.h"
+#include "mozilla/DebugOnly.h"
+#include "prinrval.h"
+#include "nsIFile.h"
+#include "nsITimer.h"
+#include "mozilla/AutoRestore.h"
+#include <algorithm>
+#include "mozilla/Telemetry.h"
+#include "mozilla/Unused.h"
+
+
+#define kMinUnwrittenChanges   300
+#define kMinDumpInterval       20000 // in milliseconds
+#define kMaxBufSize            16384
+#define kIndexVersion          0x00000003
+#define kUpdateIndexStartDelay 50000 // in milliseconds
+
+#define INDEX_NAME      "index"
+#define TEMP_INDEX_NAME "index.tmp"
+#define JOURNAL_NAME    "index.log"
+
+namespace mozilla {
+namespace net {
+
+namespace {
+
+class FrecencyComparator
+{
+public:
+  bool Equals(CacheIndexRecord* a, CacheIndexRecord* b) const {
+    if (!a || !b) {
+      return false;
+    }
+
+    return a->mFrecency == b->mFrecency;
+  }
+  bool LessThan(CacheIndexRecord* a, CacheIndexRecord* b) const {
+    // Removed (=null) entries must be at the end of the array.
+    if (!a) {
+      return false;
+    }
+    if (!b) {
+      return true;
+    }
+
+    // Place entries with frecency 0 at the end of the non-removed entries.
+    if (a->mFrecency == 0) {
+      return false;
+    }
+    if (b->mFrecency == 0) {
+      return true;
+    }
+
+    return a->mFrecency < b->mFrecency;
+  }
+};
+
+} // namespace
+
+/**
+ * This helper class is responsible for keeping CacheIndex::mIndexStats and
+ * CacheIndex::mFrecencyArray up to date.
+ */
+class CacheIndexEntryAutoManage
+{
+public:
+  CacheIndexEntryAutoManage(const SHA1Sum::Hash *aHash, CacheIndex *aIndex)
+    : mIndex(aIndex)
+    , mOldRecord(nullptr)
+    , mOldFrecency(0)
+    , mDoNotSearchInIndex(false)
+    , mDoNotSearchInUpdates(false)
+  {
+    CacheIndex::sLock.AssertCurrentThreadOwns();
+
+    mHash = aHash;
+    const CacheIndexEntry *entry = FindEntry();
+    mIndex->mIndexStats.BeforeChange(entry);
+    if (entry && entry->IsInitialized() && !entry->IsRemoved()) {
+      mOldRecord = entry->mRec;
+      mOldFrecency = entry->mRec->mFrecency;
+    }
+  }
+
+  ~CacheIndexEntryAutoManage()
+  {
+    CacheIndex::sLock.AssertCurrentThreadOwns();
+
+    const CacheIndexEntry *entry = FindEntry();
+    mIndex->mIndexStats.AfterChange(entry);
+    if (!entry || !entry->IsInitialized() || entry->IsRemoved()) {
+      entry = nullptr;
+    }
+
+    if (entry && !mOldRecord) {
+      mIndex->mFrecencyArray.AppendRecord(entry->mRec);
+      mIndex->AddRecordToIterators(entry->mRec);
+    } else if (!entry && mOldRecord) {
+      mIndex->mFrecencyArray.RemoveRecord(mOldRecord);
+      mIndex->RemoveRecordFromIterators(mOldRecord);
+    } else if (entry && mOldRecord) {
+      if (entry->mRec != mOldRecord) {
+        // record has a different address, we have to replace it
+        mIndex->ReplaceRecordInIterators(mOldRecord, entry->mRec);
+
+        if (entry->mRec->mFrecency == mOldFrecency) {
+          // If frecency hasn't changed simply replace the pointer
+          mIndex->mFrecencyArray.ReplaceRecord(mOldRecord, entry->mRec);
+        } else {
+          // Remove old pointer and insert the new one at the end of the array
+          mIndex->mFrecencyArray.RemoveRecord(mOldRecord);
+          mIndex->mFrecencyArray.AppendRecord(entry->mRec);
+        }
+      } else if (entry->mRec->mFrecency != mOldFrecency) {
+        // Move the element at the end of the array
+        mIndex->mFrecencyArray.RemoveRecord(entry->mRec);
+        mIndex->mFrecencyArray.AppendRecord(entry->mRec);
+      }
+    } else {
+      // both entries were removed or not initialized, do nothing
+    }
+  }
+
+  // We cannot rely on nsTHashtable::GetEntry() in case we are removing entries
+  // while iterating. Destructor is called before the entry is removed. Caller
+  // must call one of following methods to skip lookup in the hashtable.
+  void DoNotSearchInIndex()   { mDoNotSearchInIndex = true; }
+  void DoNotSearchInUpdates() { mDoNotSearchInUpdates = true; }
+
+private:
+  const CacheIndexEntry * FindEntry()
+  {
+    const CacheIndexEntry *entry = nullptr;
+
+    switch (mIndex->mState) {
+      case CacheIndex::READING:
+      case CacheIndex::WRITING:
+        if (!mDoNotSearchInUpdates) {
+          entry = mIndex->mPendingUpdates.GetEntry(*mHash);
+        }
+        MOZ_FALLTHROUGH;
+      case CacheIndex::BUILDING:
+      case CacheIndex::UPDATING:
+      case CacheIndex::READY:
+        if (!entry && !mDoNotSearchInIndex) {
+          entry = mIndex->mIndex.GetEntry(*mHash);
+        }
+        break;
+      case CacheIndex::INITIAL:
+      case CacheIndex::SHUTDOWN:
+      default:
+        MOZ_ASSERT(false, "Unexpected state!");
+    }
+
+    return entry;
+  }
+
+  const SHA1Sum::Hash *mHash;
+  RefPtr<CacheIndex> mIndex;
+  CacheIndexRecord    *mOldRecord;
+  uint32_t             mOldFrecency;
+  bool                 mDoNotSearchInIndex;
+  bool                 mDoNotSearchInUpdates;
+};
+
+class FileOpenHelper : public CacheFileIOListener
+{
+public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+
+  explicit FileOpenHelper(CacheIndex* aIndex)
+    : mIndex(aIndex)
+    , mCanceled(false)
+  {}
+
+  void Cancel() {
+    CacheIndex::sLock.AssertCurrentThreadOwns();
+    mCanceled = true;
+  }
+
+private:
+  virtual ~FileOpenHelper() {}
+
+  NS_IMETHOD OnFileOpened(CacheFileHandle *aHandle, nsresult aResult) override;
+  NS_IMETHOD OnDataWritten(CacheFileHandle *aHandle, const char *aBuf,
+                           nsresult aResult) override {
+    MOZ_CRASH("FileOpenHelper::OnDataWritten should not be called!");
+    return NS_ERROR_UNEXPECTED;
+  }
+  NS_IMETHOD OnDataRead(CacheFileHandle *aHandle, char *aBuf,
+                        nsresult aResult) override {
+    MOZ_CRASH("FileOpenHelper::OnDataRead should not be called!");
+    return NS_ERROR_UNEXPECTED;
+  }
+  NS_IMETHOD OnFileDoomed(CacheFileHandle *aHandle, nsresult aResult) override {
+    MOZ_CRASH("FileOpenHelper::OnFileDoomed should not be called!");
+    return NS_ERROR_UNEXPECTED;
+  }
+  NS_IMETHOD OnEOFSet(CacheFileHandle *aHandle, nsresult aResult) override {
+    MOZ_CRASH("FileOpenHelper::OnEOFSet should not be called!");
+    return NS_ERROR_UNEXPECTED;
+  }
+  NS_IMETHOD OnFileRenamed(CacheFileHandle *aHandle, nsresult aResult) override {
+    MOZ_CRASH("FileOpenHelper::OnFileRenamed should not be called!");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  RefPtr<CacheIndex> mIndex;
+  bool                 mCanceled;
+};
+
+NS_IMETHODIMP FileOpenHelper::OnFileOpened(CacheFileHandle *aHandle,
+                                           nsresult aResult)
+{
+  StaticMutexAutoLock lock(CacheIndex::sLock);
+
+  if (mCanceled) {
+    if (aHandle) {
+      CacheFileIOManager::DoomFile(aHandle, nullptr);
+    }
+
+    return NS_OK;
+  }
+
+  mIndex->OnFileOpenedInternal(this, aHandle, aResult);
+
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(FileOpenHelper, CacheFileIOListener);
+
+
+StaticRefPtr<CacheIndex> CacheIndex::gInstance;
+StaticMutex  CacheIndex::sLock;
+
+
+NS_IMPL_ADDREF(CacheIndex)
+NS_IMPL_RELEASE(CacheIndex)
+
+NS_INTERFACE_MAP_BEGIN(CacheIndex)
+  NS_INTERFACE_MAP_ENTRY(mozilla::net::CacheFileIOListener)
+  NS_INTERFACE_MAP_ENTRY(nsIRunnable)
+NS_INTERFACE_MAP_END_THREADSAFE
+
+
+CacheIndex::CacheIndex()
+  : mState(INITIAL)
+  , mShuttingDown(false)
+  , mIndexNeedsUpdate(false)
+  , mRemovingAll(false)
+  , mIndexOnDiskIsValid(false)
+  , mDontMarkIndexClean(false)
+  , mIndexTimeStamp(0)
+  , mUpdateEventPending(false)
+  , mSkipEntries(0)
+  , mProcessEntries(0)
+  , mRWBuf(nullptr)
+  , mRWBufSize(0)
+  , mRWBufPos(0)
+  , mRWPending(false)
+  , mJournalReadSuccessfully(false)
+  , mAsyncGetDiskConsumptionBlocked(false)
+{
+  sLock.AssertCurrentThreadOwns();
+  LOG(("CacheIndex::CacheIndex [this=%p]", this));
+  MOZ_COUNT_CTOR(CacheIndex);
+  MOZ_ASSERT(!gInstance, "multiple CacheIndex instances!");
+}
+
+CacheIndex::~CacheIndex()
+{
+  sLock.AssertCurrentThreadOwns();
+  LOG(("CacheIndex::~CacheIndex [this=%p]", this));
+  MOZ_COUNT_DTOR(CacheIndex);
+
+  ReleaseBuffer();
+}
+
+// static
+nsresult
+CacheIndex::Init(nsIFile *aCacheDirectory)
+{
+  LOG(("CacheIndex::Init()"));
+
+  MOZ_ASSERT(NS_IsMainThread());
+
+  StaticMutexAutoLock lock(sLock);
+
+  if (gInstance) {
+    return NS_ERROR_ALREADY_INITIALIZED;
+  }
+
+  RefPtr<CacheIndex> idx = new CacheIndex();
+
+  nsresult rv = idx->InitInternal(aCacheDirectory);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  gInstance = idx.forget();
+  return NS_OK;
+}
+
+nsresult
+CacheIndex::InitInternal(nsIFile *aCacheDirectory)
+{
+  nsresult rv;
+
+  rv = aCacheDirectory->Clone(getter_AddRefs(mCacheDirectory));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  mStartTime = TimeStamp::NowLoRes();
+
+  ReadIndexFromDisk();
+
+  return NS_OK;
+}
+
+// static
+nsresult
+CacheIndex::PreShutdown()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+
+  StaticMutexAutoLock lock(sLock);
+
+  LOG(("CacheIndex::PreShutdown() [gInstance=%p]", gInstance.get()));
+
+  nsresult rv;
+  RefPtr<CacheIndex> index = gInstance;
+
+  if (!index) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  LOG(("CacheIndex::PreShutdown() - [state=%d, indexOnDiskIsValid=%d, "
+       "dontMarkIndexClean=%d]", index->mState, index->mIndexOnDiskIsValid,
+       index->mDontMarkIndexClean));
+
+  LOG(("CacheIndex::PreShutdown() - Closing iterators."));
+  for (uint32_t i = 0; i < index->mIterators.Length(); ) {
+    rv = index->mIterators[i]->CloseInternal(NS_ERROR_FAILURE);
+    if (NS_FAILED(rv)) {
+      // CacheIndexIterator::CloseInternal() removes itself from mIteratos iff
+      // it returns success.
+      LOG(("CacheIndex::PreShutdown() - Failed to remove iterator %p. "
+           "[rv=0x%08x]", rv));
+      i++;
+    }
+  }
+
+  index->mShuttingDown = true;
+
+  if (index->mState == READY) {
+    return NS_OK; // nothing to do
+  }
+
+  nsCOMPtr<nsIRunnable> event;
+  event = NewRunnableMethod(index, &CacheIndex::PreShutdownInternal);
+
+  nsCOMPtr<nsIEventTarget> ioTarget = CacheFileIOManager::IOTarget();
+  MOZ_ASSERT(ioTarget);
+
+  // PreShutdownInternal() will be executed before any queued event on INDEX
+  // level. That's OK since we don't want to wait for any operation in progess.
+  rv = ioTarget->Dispatch(event, nsIEventTarget::DISPATCH_NORMAL);
+  if (NS_FAILED(rv)) {
+    NS_WARNING("CacheIndex::PreShutdown() - Can't dispatch event");
+    LOG(("CacheIndex::PreShutdown() - Can't dispatch event" ));
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+void
+CacheIndex::PreShutdownInternal()
+{
+  StaticMutexAutoLock lock(sLock);
+
+  LOG(("CacheIndex::PreShutdownInternal() - [state=%d, indexOnDiskIsValid=%d, "
+       "dontMarkIndexClean=%d]", mState, mIndexOnDiskIsValid,
+       mDontMarkIndexClean));
+
+  MOZ_ASSERT(mShuttingDown);
+
+  if (mUpdateTimer) {
+    mUpdateTimer = nullptr;
+  }
+
+  switch (mState) {
+    case WRITING:
+      FinishWrite(false);
+      break;
+    case READY:
+      // nothing to do, write the journal in Shutdown()
+      break;
+    case READING:
+      FinishRead(false);
+      break;
+    case BUILDING:
+    case UPDATING:
+      FinishUpdate(false);
+      break;
+    default:
+      MOZ_ASSERT(false, "Implement me!");
+  }
+
+  // We should end up in READY state
+  MOZ_ASSERT(mState == READY);
+}
+
+// static
+nsresult
+CacheIndex::Shutdown()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+
+  StaticMutexAutoLock lock(sLock);
+
+  LOG(("CacheIndex::Shutdown() [gInstance=%p]", gInstance.get()));
+
+  RefPtr<CacheIndex> index = gInstance.forget();
+
+  if (!index) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  bool sanitize = CacheObserver::ClearCacheOnShutdown();
+
+  LOG(("CacheIndex::Shutdown() - [state=%d, indexOnDiskIsValid=%d, "
+       "dontMarkIndexClean=%d, sanitize=%d]", index->mState,
+       index->mIndexOnDiskIsValid, index->mDontMarkIndexClean, sanitize));
+
+  MOZ_ASSERT(index->mShuttingDown);
+
+  EState oldState = index->mState;
+  index->ChangeState(SHUTDOWN);
+
+  if (oldState != READY) {
+    LOG(("CacheIndex::Shutdown() - Unexpected state. Did posting of "
+         "PreShutdownInternal() fail?"));
+  }
+
+  switch (oldState) {
+    case WRITING:
+      index->FinishWrite(false);
+      MOZ_FALLTHROUGH;
+    case READY:
+      if (index->mIndexOnDiskIsValid && !index->mDontMarkIndexClean) {
+        if (!sanitize && NS_FAILED(index->WriteLogToDisk())) {
+          index->RemoveJournalAndTempFile();
+        }
+      } else {
+        index->RemoveJournalAndTempFile();
+      }
+      break;
+    case READING:
+      index->FinishRead(false);
+      break;
+    case BUILDING:
+    case UPDATING:
+      index->FinishUpdate(false);
+      break;
+    default:
+      MOZ_ASSERT(false, "Unexpected state!");
+  }
+
+  if (sanitize) {
+    index->RemoveAllIndexFiles();
+  }
+
+  return NS_OK;
+}
+
+// static
+nsresult
+CacheIndex::AddEntry(const SHA1Sum::Hash *aHash)
+{
+  LOG(("CacheIndex::AddEntry() [hash=%08x%08x%08x%08x%08x]", LOGSHA1(aHash)));
+
+  MOZ_ASSERT(CacheFileIOManager::IsOnIOThread());
+
+  StaticMutexAutoLock lock(sLock);
+
+  RefPtr<CacheIndex> index = gInstance;
+
+  if (!index) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  if (!index->IsIndexUsable()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  // Getters in CacheIndexStats assert when mStateLogged is true since the
+  // information is incomplete between calls to BeforeChange() and AfterChange()
+  // (i.e. while CacheIndexEntryAutoManage exists). We need to check whether
+  // non-fresh entries exists outside the scope of CacheIndexEntryAutoManage.
+  bool updateIfNonFreshEntriesExist = false;
+
+  {
+    CacheIndexEntryAutoManage entryMng(aHash, index);
+
+    CacheIndexEntry *entry = index->mIndex.GetEntry(*aHash);
+    bool entryRemoved = entry && entry->IsRemoved();
+    CacheIndexEntryUpdate *updated = nullptr;
+
+    if (index->mState == READY || index->mState == UPDATING ||
+        index->mState == BUILDING) {
+      MOZ_ASSERT(index->mPendingUpdates.Count() == 0);
+
+      if (entry && !entryRemoved) {
+        // Found entry in index that shouldn't exist.
+
+        if (entry->IsFresh()) {
+          // Someone removed the file on disk while FF is running. Update
+          // process can fix only non-fresh entries (i.e. entries that were not
+          // added within this session). Start update only if we have such
+          // entries.
+          //
+          // TODO: This should be very rare problem. If it turns out not to be
+          // true, change the update process so that it also iterates all
+          // initialized non-empty entries and checks whether the file exists.
+
+          LOG(("CacheIndex::AddEntry() - Cache file was removed outside FF "
+               "process!"));
+
+          updateIfNonFreshEntriesExist = true;
+        } else if (index->mState == READY) {
+          // Index is outdated, update it.
+          LOG(("CacheIndex::AddEntry() - Found entry that shouldn't exist, "
+               "update is needed"));
+          index->mIndexNeedsUpdate = true;
+        } else {
+          // We cannot be here when building index since all entries are fresh
+          // during building.
+          MOZ_ASSERT(index->mState == UPDATING);
+        }
+      }
+
+      if (!entry) {
+        entry = index->mIndex.PutEntry(*aHash);
+      }
+    } else { // WRITING, READING
+      updated = index->mPendingUpdates.GetEntry(*aHash);
+      bool updatedRemoved = updated && updated->IsRemoved();
+
+      if ((updated && !updatedRemoved) ||
+          (!updated && entry && !entryRemoved && entry->IsFresh())) {
+        // Fresh entry found, so the file was removed outside FF
+        LOG(("CacheIndex::AddEntry() - Cache file was removed outside FF "
+             "process!"));
+
+        updateIfNonFreshEntriesExist = true;
+      } else if (!updated && entry && !entryRemoved) {
+        if (index->mState == WRITING) {
+          LOG(("CacheIndex::AddEntry() - Found entry that shouldn't exist, "
+               "update is needed"));
+          index->mIndexNeedsUpdate = true;
+        }
+        // Ignore if state is READING since the index information is partial
+      }
+
+      updated = index->mPendingUpdates.PutEntry(*aHash);
+    }
+
+    if (updated) {
+      updated->InitNew();
+      updated->MarkDirty();
+      updated->MarkFresh();
+    } else {
+      entry->InitNew();
+      entry->MarkDirty();
+      entry->MarkFresh();
+    }
+  }
+
+  if (updateIfNonFreshEntriesExist &&
+      index->mIndexStats.Count() != index->mIndexStats.Fresh()) {
+    index->mIndexNeedsUpdate = true;
+  }
+
+  index->StartUpdatingIndexIfNeeded();
+  index->WriteIndexToDiskIfNeeded();
+
+  return NS_OK;
+}
+
+// static
+nsresult
+CacheIndex::EnsureEntryExists(const SHA1Sum::Hash *aHash)
+{
+  LOG(("CacheIndex::EnsureEntryExists() [hash=%08x%08x%08x%08x%08x]",
+       LOGSHA1(aHash)));
+
+  MOZ_ASSERT(CacheFileIOManager::IsOnIOThread());
+
+  StaticMutexAutoLock lock(sLock);
+
+  RefPtr<CacheIndex> index = gInstance;
+
+  if (!index) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  if (!index->IsIndexUsable()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  {
+    CacheIndexEntryAutoManage entryMng(aHash, index);
+
+    CacheIndexEntry *entry = index->mIndex.GetEntry(*aHash);
+    bool entryRemoved = entry && entry->IsRemoved();
+
+    if (index->mState == READY || index->mState == UPDATING ||
+        index->mState == BUILDING) {
+      MOZ_ASSERT(index->mPendingUpdates.Count() == 0);
+
+      if (!entry || entryRemoved) {
+        if (entryRemoved && entry->IsFresh()) {
+          // This could happen only if somebody copies files to the entries
+          // directory while FF is running.
+          LOG(("CacheIndex::EnsureEntryExists() - Cache file was added outside "
+               "FF process! Update is needed."));
+          index->mIndexNeedsUpdate = true;
+        } else if (index->mState == READY ||
+                   (entryRemoved && !entry->IsFresh())) {
+          // Removed non-fresh entries can be present as a result of
+          // MergeJournal()
+          LOG(("CacheIndex::EnsureEntryExists() - Didn't find entry that should"
+               " exist, update is needed"));
+          index->mIndexNeedsUpdate = true;
+        }
+
+        if (!entry) {
+          entry = index->mIndex.PutEntry(*aHash);
+        }
+        entry->InitNew();
+        entry->MarkDirty();
+      }
+      entry->MarkFresh();
+    } else { // WRITING, READING
+      CacheIndexEntryUpdate *updated = index->mPendingUpdates.GetEntry(*aHash);
+      bool updatedRemoved = updated && updated->IsRemoved();
+
+      if (updatedRemoved ||
+          (!updated && entryRemoved && entry->IsFresh())) {
+        // Fresh information about missing entry found. This could happen only
+        // if somebody copies files to the entries directory while FF is running.
+        LOG(("CacheIndex::EnsureEntryExists() - Cache file was added outside "
+             "FF process! Update is needed."));
+        index->mIndexNeedsUpdate = true;
+      } else if (!updated && (!entry || entryRemoved)) {
+        if (index->mState == WRITING) {
+          LOG(("CacheIndex::EnsureEntryExists() - Didn't find entry that should"
+               " exist, update is needed"));
+          index->mIndexNeedsUpdate = true;
+        }
+        // Ignore if state is READING since the index information is partial
+      }
+
+      // We don't need entryRemoved and updatedRemoved info anymore
+      if (entryRemoved)   entry = nullptr;
+      if (updatedRemoved) updated = nullptr;
+
+      if (updated) {
+        updated->MarkFresh();
+      } else {
+        if (!entry) {
+          // Create a new entry
+          updated = index->mPendingUpdates.PutEntry(*aHash);
+          updated->InitNew();
+          updated->MarkFresh();
+          updated->MarkDirty();
+        } else {
+          if (!entry->IsFresh()) {
+            // To mark the entry fresh we must make a copy of index entry
+            // since the index is read-only.
+            updated = index->mPendingUpdates.PutEntry(*aHash);
+            *updated = *entry;
+            updated->MarkFresh();
+          }
+        }
+      }
+    }
+  }
+
+  index->StartUpdatingIndexIfNeeded();
+  index->WriteIndexToDiskIfNeeded();
+
+  return NS_OK;
+}
+
+// static
+nsresult
+CacheIndex::InitEntry(const SHA1Sum::Hash *aHash,
+                      OriginAttrsHash      aOriginAttrsHash,
+                      bool                 aAnonymous,
+                      bool                 aPinned)
+{
+  LOG(("CacheIndex::InitEntry() [hash=%08x%08x%08x%08x%08x, "
+       "originAttrsHash=%llx, anonymous=%d, pinned=%d]", LOGSHA1(aHash),
+       aOriginAttrsHash, aAnonymous, aPinned));
+
+  MOZ_ASSERT(CacheFileIOManager::IsOnIOThread());
+
+  StaticMutexAutoLock lock(sLock);
+
+  RefPtr<CacheIndex> index = gInstance;
+
+  if (!index) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  if (!index->IsIndexUsable()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  {
+    CacheIndexEntryAutoManage entryMng(aHash, index);
+
+    CacheIndexEntry *entry = index->mIndex.GetEntry(*aHash);
+    CacheIndexEntryUpdate *updated = nullptr;
+    bool reinitEntry = false;
+
+    if (entry && entry->IsRemoved()) {
+      entry = nullptr;
+    }
+
+    if (index->mState == READY || index->mState == UPDATING ||
+        index->mState == BUILDING) {
+      MOZ_ASSERT(index->mPendingUpdates.Count() == 0);
+      MOZ_ASSERT(entry);
+      MOZ_ASSERT(entry->IsFresh());
+
+      if (IsCollision(entry, aOriginAttrsHash, aAnonymous)) {
+        index->mIndexNeedsUpdate = true; // TODO Does this really help in case of collision?
+        reinitEntry = true;
+      } else {
+        if (entry->IsInitialized()) {
+          return NS_OK;
+        }
+      }
+    } else {
+      updated = index->mPendingUpdates.GetEntry(*aHash);
+      DebugOnly<bool> removed = updated && updated->IsRemoved();
+
+      MOZ_ASSERT(updated || !removed);
+      MOZ_ASSERT(updated || entry);
+
+      if (updated) {
+        MOZ_ASSERT(updated->IsFresh());
+
+        if (IsCollision(updated, aOriginAttrsHash, aAnonymous)) {
+          index->mIndexNeedsUpdate = true;
+          reinitEntry = true;
+        } else {
+          if (updated->IsInitialized()) {
+            return NS_OK;
+          }
+        }
+      } else {
+        MOZ_ASSERT(entry->IsFresh());
+
+        if (IsCollision(entry, aOriginAttrsHash, aAnonymous)) {
+          index->mIndexNeedsUpdate = true;
+          reinitEntry = true;
+        } else {
+          if (entry->IsInitialized()) {
+            return NS_OK;
+          }
+        }
+
+        // make a copy of a read-only entry
+        updated = index->mPendingUpdates.PutEntry(*aHash);
+        *updated = *entry;
+      }
+    }
+
+    if (reinitEntry) {
+      // There is a collision and we are going to rewrite this entry. Initialize
+      // it as a new entry.
+      if (updated) {
+        updated->InitNew();
+        updated->MarkFresh();
+      } else {
+        entry->InitNew();
+        entry->MarkFresh();
+      }
+    }
+
+    if (updated) {
+      updated->Init(aOriginAttrsHash, aAnonymous, aPinned);
+      updated->MarkDirty();
+    } else {
+      entry->Init(aOriginAttrsHash, aAnonymous, aPinned);
+      entry->MarkDirty();
+    }
+  }
+
+  index->StartUpdatingIndexIfNeeded();
+  index->WriteIndexToDiskIfNeeded();
+
+  return NS_OK;
+}
+
+// static
+nsresult
+CacheIndex::RemoveEntry(const SHA1Sum::Hash *aHash)
+{
+  LOG(("CacheIndex::RemoveEntry() [hash=%08x%08x%08x%08x%08x]",
+       LOGSHA1(aHash)));
+
+  MOZ_ASSERT(CacheFileIOManager::IsOnIOThread());
+
+  StaticMutexAutoLock lock(sLock);
+
+  RefPtr<CacheIndex> index = gInstance;
+
+  if (!index) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  if (!index->IsIndexUsable()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  {
+    CacheIndexEntryAutoManage entryMng(aHash, index);
+
+    CacheIndexEntry *entry = index->mIndex.GetEntry(*aHash);
+    bool entryRemoved = entry && entry->IsRemoved();
+
+    if (index->mState == READY || index->mState == UPDATING ||
+        index->mState == BUILDING) {
+      MOZ_ASSERT(index->mPendingUpdates.Count() == 0);
+
+      if (!entry || entryRemoved) {
+        if (entryRemoved && entry->IsFresh()) {
+          // This could happen only if somebody copies files to the entries
+          // directory while FF is running.
+          LOG(("CacheIndex::RemoveEntry() - Cache file was added outside FF "
+               "process! Update is needed."));
+          index->mIndexNeedsUpdate = true;
+        } else if (index->mState == READY ||
+                   (entryRemoved && !entry->IsFresh())) {
+          // Removed non-fresh entries can be present as a result of
+          // MergeJournal()
+          LOG(("CacheIndex::RemoveEntry() - Didn't find entry that should exist"
+               ", update is needed"));
+          index->mIndexNeedsUpdate = true;
+        }
+      } else {
+        if (entry) {
+          if (!entry->IsDirty() && entry->IsFileEmpty()) {
+            index->mIndex.RemoveEntry(entry);
+            entry = nullptr;
+          } else {
+            entry->MarkRemoved();
+            entry->MarkDirty();
+            entry->MarkFresh();
+          }
+        }
+      }
+    } else { // WRITING, READING
+      CacheIndexEntryUpdate *updated = index->mPendingUpdates.GetEntry(*aHash);
+      bool updatedRemoved = updated && updated->IsRemoved();
+
+      if (updatedRemoved ||
+          (!updated && entryRemoved && entry->IsFresh())) {
+        // Fresh information about missing entry found. This could happen only
+        // if somebody copies files to the entries directory while FF is running.
+        LOG(("CacheIndex::RemoveEntry() - Cache file was added outside FF "
+             "process! Update is needed."));
+        index->mIndexNeedsUpdate = true;
+      } else if (!updated && (!entry || entryRemoved)) {
+        if (index->mState == WRITING) {
+          LOG(("CacheIndex::RemoveEntry() - Didn't find entry that should exist"
+               ", update is needed"));
+          index->mIndexNeedsUpdate = true;
+        }
+        // Ignore if state is READING since the index information is partial
+      }
+
+      if (!updated) {
+        updated = index->mPendingUpdates.PutEntry(*aHash);
+        updated->InitNew();
+      }
+
+      updated->MarkRemoved();
+      updated->MarkDirty();
+      updated->MarkFresh();
+    }
+  }
+
+  index->StartUpdatingIndexIfNeeded();
+  index->WriteIndexToDiskIfNeeded();
+
+  return NS_OK;
+}
+
+// static
+nsresult
+CacheIndex::UpdateEntry(const SHA1Sum::Hash *aHash,
+                        const uint32_t      *aFrecency,
+                        const uint32_t      *aExpirationTime,
+                        const uint32_t      *aSize)
+{
+  LOG(("CacheIndex::UpdateEntry() [hash=%08x%08x%08x%08x%08x, "
+       "frecency=%s, expirationTime=%s, size=%s]", LOGSHA1(aHash),
+       aFrecency ? nsPrintfCString("%u", *aFrecency).get() : "",
+       aExpirationTime ? nsPrintfCString("%u", *aExpirationTime).get() : "",
+       aSize ? nsPrintfCString("%u", *aSize).get() : ""));
+
+  MOZ_ASSERT(CacheFileIOManager::IsOnIOThread());
+
+  StaticMutexAutoLock lock(sLock);
+
+  RefPtr<CacheIndex> index = gInstance;
+
+  if (!index) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  if (!index->IsIndexUsable()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  {
+    CacheIndexEntryAutoManage entryMng(aHash, index);
+
+    CacheIndexEntry *entry = index->mIndex.GetEntry(*aHash);
+
+    if (entry && entry->IsRemoved()) {
+      entry = nullptr;
+    }
+
+    if (index->mState == READY || index->mState == UPDATING ||
+        index->mState == BUILDING) {
+      MOZ_ASSERT(index->mPendingUpdates.Count() == 0);
+      MOZ_ASSERT(entry);
+
+      if (!HasEntryChanged(entry, aFrecency, aExpirationTime, aSize)) {
+        return NS_OK;
+      }
+
+      MOZ_ASSERT(entry->IsFresh());
+      MOZ_ASSERT(entry->IsInitialized());
+      entry->MarkDirty();
+
+      if (aFrecency) {
+        entry->SetFrecency(*aFrecency);
+      }
+
+      if (aExpirationTime) {
+        entry->SetExpirationTime(*aExpirationTime);
+      }
+
+      if (aSize) {
+        entry->SetFileSize(*aSize);
+      }
+    } else {
+      CacheIndexEntryUpdate *updated = index->mPendingUpdates.GetEntry(*aHash);
+      DebugOnly<bool> removed = updated && updated->IsRemoved();
+
+      MOZ_ASSERT(updated || !removed);
+      MOZ_ASSERT(updated || entry);
+
+      if (!updated) {
+        if (!entry) {
+          LOG(("CacheIndex::UpdateEntry() - Entry was found neither in mIndex "
+               "nor in mPendingUpdates!"));
+          NS_WARNING(("CacheIndex::UpdateEntry() - Entry was found neither in "
+                      "mIndex nor in mPendingUpdates!"));
+          return NS_ERROR_NOT_AVAILABLE;
+        }
+
+        // make a copy of a read-only entry
+        updated = index->mPendingUpdates.PutEntry(*aHash);
+        *updated = *entry;
+      }
+
+      MOZ_ASSERT(updated->IsFresh());
+      MOZ_ASSERT(updated->IsInitialized());
+      updated->MarkDirty();
+
+      if (aFrecency) {
+        updated->SetFrecency(*aFrecency);
+      }
+
+      if (aExpirationTime) {
+        updated->SetExpirationTime(*aExpirationTime);
+      }
+
+      if (aSize) {
+        updated->SetFileSize(*aSize);
+      }
+    }
+  }
+
+  index->WriteIndexToDiskIfNeeded();
+
+  return NS_OK;
+}
+
+// static
+nsresult
+CacheIndex::RemoveAll()
+{
+  LOG(("CacheIndex::RemoveAll()"));
+
+  MOZ_ASSERT(CacheFileIOManager::IsOnIOThread());
+
+  nsCOMPtr<nsIFile> file;
+
+  {
+    StaticMutexAutoLock lock(sLock);
+
+    RefPtr<CacheIndex> index = gInstance;
+
+    if (!index) {
+      return NS_ERROR_NOT_INITIALIZED;
+    }
+
+    MOZ_ASSERT(!index->mRemovingAll);
+
+    if (!index->IsIndexUsable()) {
+      return NS_ERROR_NOT_AVAILABLE;
+    }
+
+    AutoRestore<bool> saveRemovingAll(index->mRemovingAll);
+    index->mRemovingAll = true;
+
+    // Doom index and journal handles but don't null them out since this will be
+    // done in FinishWrite/FinishRead methods.
+    if (index->mIndexHandle) {
+      CacheFileIOManager::DoomFile(index->mIndexHandle, nullptr);
+    } else {
+      // We don't have a handle to index file, so get the file here, but delete
+      // it outside the lock. Ignore the result since this is not fatal.
+      index->GetFile(NS_LITERAL_CSTRING(INDEX_NAME), getter_AddRefs(file));
+    }
+
+    if (index->mJournalHandle) {
+      CacheFileIOManager::DoomFile(index->mJournalHandle, nullptr);
+    }
+
+    switch (index->mState) {
+      case WRITING:
+        index->FinishWrite(false);
+        break;
+      case READY:
+        // nothing to do
+        break;
+      case READING:
+        index->FinishRead(false);
+        break;
+      case BUILDING:
+      case UPDATING:
+        index->FinishUpdate(false);
+        break;
+      default:
+        MOZ_ASSERT(false, "Unexpected state!");
+    }
+
+    // We should end up in READY state
+    MOZ_ASSERT(index->mState == READY);
+
+    // There should not be any handle
+    MOZ_ASSERT(!index->mIndexHandle);
+    MOZ_ASSERT(!index->mJournalHandle);
+
+    index->mIndexOnDiskIsValid = false;
+    index->mIndexNeedsUpdate = false;
+
+    index->mIndexStats.Clear();
+    index->mFrecencyArray.Clear();
+    index->mIndex.Clear();
+
+    for (uint32_t i = 0; i < index->mIterators.Length(); ) {
+      nsresult rv = index->mIterators[i]->CloseInternal(NS_ERROR_NOT_AVAILABLE);
+      if (NS_FAILED(rv)) {
+        // CacheIndexIterator::CloseInternal() removes itself from mIterators
+        // iff it returns success.
+        LOG(("CacheIndex::RemoveAll() - Failed to remove iterator %p. "
+             "[rv=0x%08x]", rv));
+        i++;
+      }
+    }
+  }
+
+  if (file) {
+    // Ignore the result. The file might not exist and the failure is not fatal.
+    file->Remove(false);
+  }
+
+  return NS_OK;
+}
+
+// static
+nsresult
+CacheIndex::HasEntry(const nsACString &aKey, EntryStatus *_retval, bool *_pinned)
+{
+  LOG(("CacheIndex::HasEntry() [key=%s]", PromiseFlatCString(aKey).get()));
+
+  SHA1Sum sum;
+  SHA1Sum::Hash hash;
+  sum.update(aKey.BeginReading(), aKey.Length());
+  sum.finish(hash);
+
+  return HasEntry(hash, _retval, _pinned);
+}
+
+// static
+nsresult
+CacheIndex::HasEntry(const SHA1Sum::Hash &hash, EntryStatus *_retval, bool *_pinned)
+{
+  StaticMutexAutoLock lock(sLock);
+
+  RefPtr<CacheIndex> index = gInstance;
+
+  if (!index) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  if (!index->IsIndexUsable()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  if (_pinned) {
+    *_pinned = false;
+  }
+
+  const CacheIndexEntry *entry = nullptr;
+
+  switch (index->mState) {
+    case READING:
+    case WRITING:
+      entry = index->mPendingUpdates.GetEntry(hash);
+      MOZ_FALLTHROUGH;
+    case BUILDING:
+    case UPDATING:
+    case READY:
+      if (!entry) {
+        entry = index->mIndex.GetEntry(hash);
+      }
+      break;
+    case INITIAL:
+    case SHUTDOWN:
+      MOZ_ASSERT(false, "Unexpected state!");
+  }
+
+  if (!entry) {
+    if (index->mState == READY || index->mState == WRITING) {
+      *_retval = DOES_NOT_EXIST;
+    } else {
+      *_retval = DO_NOT_KNOW;
+    }
+  } else {
+    if (entry->IsRemoved()) {
+      if (entry->IsFresh()) {
+        *_retval = DOES_NOT_EXIST;
+      } else {
+        *_retval = DO_NOT_KNOW;
+      }
+    } else {
+      *_retval = EXISTS;
+      if (_pinned && entry->IsPinned()) {
+        *_pinned = true;
+      }
+    }
+  }
+
+  LOG(("CacheIndex::HasEntry() - result is %u", *_retval));
+  return NS_OK;
+}
+
+// static
+nsresult
+CacheIndex::GetEntryForEviction(bool aIgnoreEmptyEntries, SHA1Sum::Hash *aHash, uint32_t *aCnt)
+{
+  LOG(("CacheIndex::GetEntryForEviction()"));
+
+  MOZ_ASSERT(CacheFileIOManager::IsOnIOThread());
+
+  StaticMutexAutoLock lock(sLock);
+
+  RefPtr<CacheIndex> index = gInstance;
+
+  if (!index)
+    return NS_ERROR_NOT_INITIALIZED;
+
+  if (!index->IsIndexUsable()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  SHA1Sum::Hash hash;
+  CacheIndexRecord *foundRecord = nullptr;
+  uint32_t skipped = 0;
+
+  // find first non-forced valid and unpinned entry with the lowest frecency
+  index->mFrecencyArray.SortIfNeeded();
+
+  for (auto iter = index->mFrecencyArray.Iter(); !iter.Done(); iter.Next()) {
+    CacheIndexRecord *rec = iter.Get();
+
+    memcpy(&hash, rec->mHash, sizeof(SHA1Sum::Hash));
+
+    ++skipped;
+
+    if (IsForcedValidEntry(&hash)) {
+      continue;
+    }
+
+    if (CacheIndexEntry::IsPinned(rec)) {
+      continue;
+    }
+
+    if (aIgnoreEmptyEntries && !CacheIndexEntry::GetFileSize(rec)) {
+      continue;
+    }
+
+    --skipped;
+    foundRecord = rec;
+    break;
+  }
+
+  if (!foundRecord)
+    return NS_ERROR_NOT_AVAILABLE;
+
+  *aCnt = skipped;
+
+  LOG(("CacheIndex::GetEntryForEviction() - returning entry from frecency "
+        "array [hash=%08x%08x%08x%08x%08x, cnt=%u, frecency=%u]",
+        LOGSHA1(&hash), *aCnt, foundRecord->mFrecency));
+
+  memcpy(aHash, &hash, sizeof(SHA1Sum::Hash));
+
+  return NS_OK;
+}
+
+
+// static
+bool CacheIndex::IsForcedValidEntry(const SHA1Sum::Hash *aHash)
+{
+  RefPtr<CacheFileHandle> handle;
+
+  CacheFileIOManager::gInstance->mHandles.GetHandle(
+    aHash, getter_AddRefs(handle));
+
+  if (!handle)
+    return false;
+
+  nsCString hashKey = handle->Key();
+  return CacheStorageService::Self()->IsForcedValidEntry(hashKey);
+}
+
+
+// static
+nsresult
+CacheIndex::GetCacheSize(uint32_t *_retval)
+{
+  LOG(("CacheIndex::GetCacheSize()"));
+
+  StaticMutexAutoLock lock(sLock);
+
+  RefPtr<CacheIndex> index = gInstance;
+
+  if (!index)
+    return NS_ERROR_NOT_INITIALIZED;
+
+  if (!index->IsIndexUsable()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  *_retval = index->mIndexStats.Size();
+  LOG(("CacheIndex::GetCacheSize() - returning %u", *_retval));
+  return NS_OK;
+}
+
+// static
+nsresult
+CacheIndex::GetEntryFileCount(uint32_t *_retval)
+{
+  LOG(("CacheIndex::GetEntryFileCount()"));
+
+  StaticMutexAutoLock lock(sLock);
+
+  RefPtr<CacheIndex> index = gInstance;
+
+  if (!index) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  if (!index->IsIndexUsable()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  *_retval = index->mIndexStats.ActiveEntriesCount();
+  LOG(("CacheIndex::GetEntryFileCount() - returning %u", *_retval));
+  return NS_OK;
+}
+
+// static
+nsresult
+CacheIndex::GetCacheStats(nsILoadContextInfo *aInfo, uint32_t *aSize, uint32_t *aCount)
+{
+  LOG(("CacheIndex::GetCacheStats() [info=%p]", aInfo));
+
+  StaticMutexAutoLock lock(sLock);
+
+  RefPtr<CacheIndex> index = gInstance;
+
+  if (!index) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  if (!index->IsIndexUsable()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  if (!aInfo) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  *aSize = 0;
+  *aCount = 0;
+
+  for (auto iter = index->mFrecencyArray.Iter(); !iter.Done(); iter.Next()) {
+    CacheIndexRecord *record = iter.Get();
+    if (!CacheIndexEntry::RecordMatchesLoadContextInfo(record, aInfo))
+      continue;
+
+    *aSize += CacheIndexEntry::GetFileSize(record);
+    ++*aCount;
+  }
+
+  return NS_OK;
+}
+
+// static
+nsresult
+CacheIndex::AsyncGetDiskConsumption(nsICacheStorageConsumptionObserver* aObserver)
+{
+  LOG(("CacheIndex::AsyncGetDiskConsumption()"));
+
+  StaticMutexAutoLock lock(sLock);
+
+  RefPtr<CacheIndex> index = gInstance;
+
+  if (!index) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  if (!index->IsIndexUsable()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  RefPtr<DiskConsumptionObserver> observer =
+    DiskConsumptionObserver::Init(aObserver);
+
+  NS_ENSURE_ARG(observer);
+
+  if ((index->mState == READY || index->mState == WRITING) &&
+      !index->mAsyncGetDiskConsumptionBlocked) {
+    LOG(("CacheIndex::AsyncGetDiskConsumption - calling immediately"));
+    // Safe to call the callback under the lock,
+    // we always post to the main thread.
+    observer->OnDiskConsumption(index->mIndexStats.Size() << 10);
+    return NS_OK;
+  }
+
+  LOG(("CacheIndex::AsyncGetDiskConsumption - remembering callback"));
+  // Will be called when the index get to the READY state.
+  index->mDiskConsumptionObservers.AppendElement(observer);
+
+  // Move forward with index re/building if it is pending
+  RefPtr<CacheIOThread> ioThread = CacheFileIOManager::IOThread();
+  if (ioThread) {
+    ioThread->Dispatch(NS_NewRunnableFunction([]() -> void {
+      StaticMutexAutoLock lock(sLock);
+
+      RefPtr<CacheIndex> index = gInstance;
+      if (index && index->mUpdateTimer) {
+        index->mUpdateTimer->Cancel();
+        index->DelayedUpdateLocked();
+      }
+    }), CacheIOThread::INDEX);
+  }
+
+  return NS_OK;
+}
+
+// static
+nsresult
+CacheIndex::GetIterator(nsILoadContextInfo *aInfo, bool aAddNew,
+                        CacheIndexIterator **_retval)
+{
+  LOG(("CacheIndex::GetIterator() [info=%p, addNew=%d]", aInfo, aAddNew));
+
+  StaticMutexAutoLock lock(sLock);
+
+  RefPtr<CacheIndex> index = gInstance;
+
+  if (!index) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  if (!index->IsIndexUsable()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  RefPtr<CacheIndexIterator> idxIter;
+  if (aInfo) {
+    idxIter = new CacheIndexContextIterator(index, aAddNew, aInfo);
+  } else {
+    idxIter = new CacheIndexIterator(index, aAddNew);
+  }
+
+  index->mFrecencyArray.SortIfNeeded();
+
+  for (auto iter = index->mFrecencyArray.Iter(); !iter.Done(); iter.Next()) {
+    idxIter->AddRecord(iter.Get());
+  }
+
+  index->mIterators.AppendElement(idxIter);
+  idxIter.swap(*_retval);
+  return NS_OK;
+}
+
+// static
+nsresult
+CacheIndex::IsUpToDate(bool *_retval)
+{
+  LOG(("CacheIndex::IsUpToDate()"));
+
+  StaticMutexAutoLock lock(sLock);
+
+  RefPtr<CacheIndex> index = gInstance;
+
+  if (!index) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  if (!index->IsIndexUsable()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  *_retval = (index->mState == READY || index->mState == WRITING) &&
+             !index->mIndexNeedsUpdate && !index->mShuttingDown;
+
+  LOG(("CacheIndex::IsUpToDate() - returning %p", *_retval));
+  return NS_OK;
+}
+
+bool
+CacheIndex::IsIndexUsable()
+{
+  MOZ_ASSERT(mState != INITIAL);
+
+  switch (mState) {
+    case INITIAL:
+    case SHUTDOWN:
+      return false;
+
+    case READING:
+    case WRITING:
+    case BUILDING:
+    case UPDATING:
+    case READY:
+      break;
+  }
+
+  return true;
+}
+
+// static
+bool
+CacheIndex::IsCollision(CacheIndexEntry *aEntry,
+                        OriginAttrsHash  aOriginAttrsHash,
+                        bool             aAnonymous)
+{
+  if (!aEntry->IsInitialized()) {
+    return false;
+  }
+
+  if (aEntry->Anonymous() != aAnonymous ||
+      aEntry->OriginAttrsHash() != aOriginAttrsHash) {
+    LOG(("CacheIndex::IsCollision() - Collision detected for entry hash=%08x"
+         "%08x%08x%08x%08x, expected values: originAttrsHash=%llx, "
+         "anonymous=%d; actual values: originAttrsHash=%llx, anonymous=%d]",
+         LOGSHA1(aEntry->Hash()), aOriginAttrsHash, aAnonymous,
+         aEntry->OriginAttrsHash(), aEntry->Anonymous()));
+    return true;
+  }
+
+  return false;
+}
+
+// static
+bool
+CacheIndex::HasEntryChanged(CacheIndexEntry *aEntry,
+                            const uint32_t  *aFrecency,
+                            const uint32_t  *aExpirationTime,
+                            const uint32_t  *aSize)
+{
+  if (aFrecency && *aFrecency != aEntry->GetFrecency()) {
+    return true;
+  }
+
+  if (aExpirationTime && *aExpirationTime != aEntry->GetExpirationTime()) {
+    return true;
+  }
+
+  if (aSize &&
+      (*aSize & CacheIndexEntry::kFileSizeMask) != aEntry->GetFileSize()) {
+    return true;
+  }
+
+  return false;
+}
+
+void
+CacheIndex::ProcessPendingOperations()
+{
+  LOG(("CacheIndex::ProcessPendingOperations()"));
+
+  sLock.AssertCurrentThreadOwns();
+
+  for (auto iter = mPendingUpdates.Iter(); !iter.Done(); iter.Next()) {
+    CacheIndexEntryUpdate* update = iter.Get();
+
+    LOG(("CacheIndex::ProcessPendingOperations() [hash=%08x%08x%08x%08x%08x]",
+         LOGSHA1(update->Hash())));
+
+    MOZ_ASSERT(update->IsFresh());
+
+    CacheIndexEntry* entry = mIndex.GetEntry(*update->Hash());
+
+    {
+      CacheIndexEntryAutoManage emng(update->Hash(), this);
+      emng.DoNotSearchInUpdates();
+
+      if (update->IsRemoved()) {
+        if (entry) {
+          if (entry->IsRemoved()) {
+            MOZ_ASSERT(entry->IsFresh());
+            MOZ_ASSERT(entry->IsDirty());
+          } else if (!entry->IsDirty() && entry->IsFileEmpty()) {
+            // Entries with empty file are not stored in index on disk. Just
+            // remove the entry, but only in case the entry is not dirty, i.e.
+            // the entry file was empty when we wrote the index.
+            mIndex.RemoveEntry(*update->Hash());
+            entry = nullptr;
+          } else {
+            entry->MarkRemoved();
+            entry->MarkDirty();
+            entry->MarkFresh();
+          }
+        }
+      } else if (entry) {
+        // Some information in mIndex can be newer than in mPendingUpdates (see
+        // bug 1074832). This will copy just those values that were really
+        // updated.
+        update->ApplyUpdate(entry);
+      } else {
+        // There is no entry in mIndex, copy all information from
+        // mPendingUpdates to mIndex.
+        entry = mIndex.PutEntry(*update->Hash());
+        *entry = *update;
+      }
+    }
+
+    iter.Remove();
+  }
+
+  MOZ_ASSERT(mPendingUpdates.Count() == 0);
+
+  EnsureCorrectStats();
+}
+
+bool
+CacheIndex::WriteIndexToDiskIfNeeded()
+{
+  if (mState != READY || mShuttingDown || mRWPending) {
+    return false;
+  }
+
+  if (!mLastDumpTime.IsNull() &&
+      (TimeStamp::NowLoRes() - mLastDumpTime).ToMilliseconds() <
+      kMinDumpInterval) {
+    return false;
+  }
+
+  if (mIndexStats.Dirty() < kMinUnwrittenChanges) {
+    return false;
+  }
+
+  WriteIndexToDisk();
+  return true;
+}
+
+void
+CacheIndex::WriteIndexToDisk()
+{
+  LOG(("CacheIndex::WriteIndexToDisk()"));
+  mIndexStats.Log();
+
+  nsresult rv;
+
+  sLock.AssertCurrentThreadOwns();
+  MOZ_ASSERT(mState == READY);
+  MOZ_ASSERT(!mRWBuf);
+  MOZ_ASSERT(!mRWHash);
+  MOZ_ASSERT(!mRWPending);
+
+  ChangeState(WRITING);
+
+  mProcessEntries = mIndexStats.ActiveEntriesCount();
+
+  mIndexFileOpener = new FileOpenHelper(this);
+  rv = CacheFileIOManager::OpenFile(NS_LITERAL_CSTRING(TEMP_INDEX_NAME),
+                                    CacheFileIOManager::SPECIAL_FILE |
+                                    CacheFileIOManager::CREATE,
+                                    mIndexFileOpener);
+  if (NS_FAILED(rv)) {
+    LOG(("CacheIndex::WriteIndexToDisk() - Can't open file [rv=0x%08x]", rv));
+    FinishWrite(false);
+    return;
+  }
+
+  // Write index header to a buffer, it will be written to disk together with
+  // records in WriteRecords() once we open the file successfully.
+  AllocBuffer();
+  mRWHash = new CacheHash();
+
+  mRWBufPos = 0;
+  // index version
+  NetworkEndian::writeUint32(mRWBuf + mRWBufPos, kIndexVersion);
+  mRWBufPos += sizeof(uint32_t);
+  // timestamp
+  NetworkEndian::writeUint32(mRWBuf + mRWBufPos,
+                             static_cast<uint32_t>(PR_Now() / PR_USEC_PER_SEC));
+  mRWBufPos += sizeof(uint32_t);
+  // dirty flag
+  NetworkEndian::writeUint32(mRWBuf + mRWBufPos, 1);
+  mRWBufPos += sizeof(uint32_t);
+
+  mSkipEntries = 0;
+}
+
+void
+CacheIndex::WriteRecords()
+{
+  LOG(("CacheIndex::WriteRecords()"));
+
+  nsresult rv;
+
+  sLock.AssertCurrentThreadOwns();
+  MOZ_ASSERT(mState == WRITING);
+  MOZ_ASSERT(!mRWPending);
+
+  int64_t fileOffset;
+
+  if (mSkipEntries) {
+    MOZ_ASSERT(mRWBufPos == 0);
+    fileOffset = sizeof(CacheIndexHeader);
+    fileOffset += sizeof(CacheIndexRecord) * mSkipEntries;
+  } else {
+    MOZ_ASSERT(mRWBufPos == sizeof(CacheIndexHeader));
+    fileOffset = 0;
+  }
+  uint32_t hashOffset = mRWBufPos;
+
+  char* buf = mRWBuf + mRWBufPos;
+  uint32_t skip = mSkipEntries;
+  uint32_t processMax = (mRWBufSize - mRWBufPos) / sizeof(CacheIndexRecord);
+  MOZ_ASSERT(processMax != 0 || mProcessEntries == 0); // TODO make sure we can write an empty index
+  uint32_t processed = 0;
+#ifdef DEBUG
+  bool hasMore = false;
+#endif
+  for (auto iter = mIndex.Iter(); !iter.Done(); iter.Next()) {
+    CacheIndexEntry* entry = iter.Get();
+    if (entry->IsRemoved() ||
+        !entry->IsInitialized() ||
+        entry->IsFileEmpty()) {
+      continue;
+    }
+
+    if (skip) {
+      skip--;
+      continue;
+    }
+
+    if (processed == processMax) {
+  #ifdef DEBUG
+      hasMore = true;
+  #endif
+      break;
+    }
+
+    entry->WriteToBuf(buf);
+    buf += sizeof(CacheIndexRecord);
+    processed++;
+  }
+
+  MOZ_ASSERT(mRWBufPos != static_cast<uint32_t>(buf - mRWBuf) ||
+             mProcessEntries == 0);
+  mRWBufPos = buf - mRWBuf;
+  mSkipEntries += processed;
+  MOZ_ASSERT(mSkipEntries <= mProcessEntries);
+
+  mRWHash->Update(mRWBuf + hashOffset, mRWBufPos - hashOffset);
+
+  if (mSkipEntries == mProcessEntries) {
+    MOZ_ASSERT(!hasMore);
+
+    // We've processed all records
+    if (mRWBufPos + sizeof(CacheHash::Hash32_t) > mRWBufSize) {
+      // realloc buffer to spare another write cycle
+      mRWBufSize = mRWBufPos + sizeof(CacheHash::Hash32_t);
+      mRWBuf = static_cast<char *>(moz_xrealloc(mRWBuf, mRWBufSize));
+    }
+
+    NetworkEndian::writeUint32(mRWBuf + mRWBufPos, mRWHash->GetHash());
+    mRWBufPos += sizeof(CacheHash::Hash32_t);
+  } else {
+    MOZ_ASSERT(hasMore);
+  }
+
+  rv = CacheFileIOManager::Write(mIndexHandle, fileOffset, mRWBuf, mRWBufPos,
+                                 mSkipEntries == mProcessEntries, false, this);
+  if (NS_FAILED(rv)) {
+    LOG(("CacheIndex::WriteRecords() - CacheFileIOManager::Write() failed "
+         "synchronously [rv=0x%08x]", rv));
+    FinishWrite(false);
+  } else {
+    mRWPending = true;
+  }
+
+  mRWBufPos = 0;
+}
+
+void
+CacheIndex::FinishWrite(bool aSucceeded)
+{
+  LOG(("CacheIndex::FinishWrite() [succeeded=%d]", aSucceeded));
+
+  MOZ_ASSERT((!aSucceeded && mState == SHUTDOWN) || mState == WRITING);
+
+  sLock.AssertCurrentThreadOwns();
+
+  // If there is write operation pending we must be cancelling writing of the
+  // index when shutting down or removing the whole index.
+  MOZ_ASSERT(!mRWPending || (!aSucceeded && (mShuttingDown || mRemovingAll)));
+
+  mIndexHandle = nullptr;
+  mRWHash = nullptr;
+  ReleaseBuffer();
+
+  if (aSucceeded) {
+    // Opening of the file must not be in progress if writing succeeded.
+    MOZ_ASSERT(!mIndexFileOpener);
+
+    for (auto iter = mIndex.Iter(); !iter.Done(); iter.Next()) {
+      CacheIndexEntry* entry = iter.Get();
+
+      bool remove = false;
+      {
+        CacheIndexEntryAutoManage emng(entry->Hash(), this);
+
+        if (entry->IsRemoved()) {
+          emng.DoNotSearchInIndex();
+          remove = true;
+        } else if (entry->IsDirty()) {
+          entry->ClearDirty();
+        }
+      }
+      if (remove) {
+        iter.Remove();
+      }
+    }
+
+    mIndexOnDiskIsValid = true;
+  } else {
+    if (mIndexFileOpener) {
+      // If opening of the file is still in progress (e.g. WRITE process was
+      // canceled by RemoveAll()) then we need to cancel the opener to make sure
+      // that OnFileOpenedInternal() won't be called.
+      mIndexFileOpener->Cancel();
+      mIndexFileOpener = nullptr;
+    }
+  }
+
+  ProcessPendingOperations();
+  mIndexStats.Log();
+
+  if (mState == WRITING) {
+    ChangeState(READY);
+    mLastDumpTime = TimeStamp::NowLoRes();
+  }
+}
+
+nsresult
+CacheIndex::GetFile(const nsACString &aName, nsIFile **_retval)
+{
+  nsresult rv;
+
+  nsCOMPtr<nsIFile> file;
+  rv = mCacheDirectory->Clone(getter_AddRefs(file));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = file->AppendNative(aName);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  file.swap(*_retval);
+  return NS_OK;
+}
+
+nsresult
+CacheIndex::RemoveFile(const nsACString &aName)
+{
+  MOZ_ASSERT(mState == SHUTDOWN);
+
+  nsresult rv;
+
+  nsCOMPtr<nsIFile> file;
+  rv = GetFile(aName, getter_AddRefs(file));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool exists;
+  rv = file->Exists(&exists);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (exists) {
+    rv = file->Remove(false);
+    if (NS_FAILED(rv)) {
+      LOG(("CacheIndex::RemoveFile() - Cannot remove old entry file from disk."
+           "[name=%s]", PromiseFlatCString(aName).get()));
+      NS_WARNING("Cannot remove old entry file from the disk");
+      return rv;
+    }
+  }
+
+  return NS_OK;
+}
+
+void
+CacheIndex::RemoveAllIndexFiles()
+{
+  LOG(("CacheIndex::RemoveAllIndexFiles()"));
+  RemoveFile(NS_LITERAL_CSTRING(INDEX_NAME));
+  RemoveJournalAndTempFile();
+}
+
+void
+CacheIndex::RemoveJournalAndTempFile()
+{
+  LOG(("CacheIndex::RemoveJournalAndTempFile()"));
+  RemoveFile(NS_LITERAL_CSTRING(TEMP_INDEX_NAME));
+  RemoveFile(NS_LITERAL_CSTRING(JOURNAL_NAME));
+}
+
+class WriteLogHelper
+{
+public:
+  explicit WriteLogHelper(PRFileDesc *aFD)
+    : mFD(aFD)
+    , mBufSize(kMaxBufSize)
+    , mBufPos(0)
+  {
+    mHash = new CacheHash();
+    mBuf = static_cast<char *>(moz_xmalloc(mBufSize));
+  }
+
+  ~WriteLogHelper() {
+    free(mBuf);
+  }
+
+  nsresult AddEntry(CacheIndexEntry *aEntry);
+  nsresult Finish();
+
+private:
+
+  nsresult FlushBuffer();
+
+  PRFileDesc       *mFD;
+  char             *mBuf;
+  uint32_t          mBufSize;
+  int32_t           mBufPos;
+  RefPtr<CacheHash> mHash;
+};
+
+nsresult
+WriteLogHelper::AddEntry(CacheIndexEntry *aEntry)
+{
+  nsresult rv;
+
+  if (mBufPos + sizeof(CacheIndexRecord) > mBufSize) {
+    mHash->Update(mBuf, mBufPos);
+
+    rv = FlushBuffer();
+    NS_ENSURE_SUCCESS(rv, rv);
+    MOZ_ASSERT(mBufPos + sizeof(CacheIndexRecord) <= mBufSize);
+  }
+
+  aEntry->WriteToBuf(mBuf + mBufPos);
+  mBufPos += sizeof(CacheIndexRecord);
+
+  return NS_OK;
+}
+
+nsresult
+WriteLogHelper::Finish()
+{
+  nsresult rv;
+
+  mHash->Update(mBuf, mBufPos);
+  if (mBufPos + sizeof(CacheHash::Hash32_t) > mBufSize) {
+    rv = FlushBuffer();
+    NS_ENSURE_SUCCESS(rv, rv);
+    MOZ_ASSERT(mBufPos + sizeof(CacheHash::Hash32_t) <= mBufSize);
+  }
+
+  NetworkEndian::writeUint32(mBuf + mBufPos, mHash->GetHash());
+  mBufPos += sizeof(CacheHash::Hash32_t);
+
+  rv = FlushBuffer();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult
+WriteLogHelper::FlushBuffer()
+{
+  if (CacheObserver::IsPastShutdownIOLag()) {
+    LOG(("WriteLogHelper::FlushBuffer() - Interrupting writing journal."));
+    return NS_ERROR_FAILURE;
+  }
+
+  int32_t bytesWritten = PR_Write(mFD, mBuf, mBufPos);
+
+  if (bytesWritten != mBufPos) {
+    return NS_ERROR_FAILURE;
+  }
+
+  mBufPos = 0;
+  return NS_OK;
+}
+
+nsresult
+CacheIndex::WriteLogToDisk()
+{
+  LOG(("CacheIndex::WriteLogToDisk()"));
+
+  nsresult rv;
+
+  MOZ_ASSERT(mPendingUpdates.Count() == 0);
+  MOZ_ASSERT(mState == SHUTDOWN);
+
+  if (CacheObserver::IsPastShutdownIOLag()) {
+    LOG(("CacheIndex::WriteLogToDisk() - Skipping writing journal."));
+    return NS_ERROR_FAILURE;
+  }
+
+  RemoveFile(NS_LITERAL_CSTRING(TEMP_INDEX_NAME));
+
+  nsCOMPtr<nsIFile> indexFile;
+  rv = GetFile(NS_LITERAL_CSTRING(INDEX_NAME), getter_AddRefs(indexFile));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIFile> logFile;
+  rv = GetFile(NS_LITERAL_CSTRING(JOURNAL_NAME), getter_AddRefs(logFile));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  mIndexStats.Log();
+
+  PRFileDesc *fd = nullptr;
+  rv = logFile->OpenNSPRFileDesc(PR_RDWR | PR_CREATE_FILE | PR_TRUNCATE,
+                                 0600, &fd);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  WriteLogHelper wlh(fd);
+  for (auto iter = mIndex.Iter(); !iter.Done(); iter.Next()) {
+    CacheIndexEntry* entry = iter.Get();
+    if (entry->IsRemoved() || entry->IsDirty()) {
+      rv = wlh.AddEntry(entry);
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return rv;
+      }
+    }
+  }
+
+  rv = wlh.Finish();
+  PR_Close(fd);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = indexFile->OpenNSPRFileDesc(PR_RDWR, 0600, &fd);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Seek to dirty flag in the index header and clear it.
+  static_assert(2 * sizeof(uint32_t) == offsetof(CacheIndexHeader, mIsDirty),
+                "Unexpected offset of CacheIndexHeader::mIsDirty");
+  int64_t offset = PR_Seek64(fd, 2 * sizeof(uint32_t), PR_SEEK_SET);
+  if (offset == -1) {
+    PR_Close(fd);
+    return NS_ERROR_FAILURE;
+  }
+
+  uint32_t isDirty = 0;
+  int32_t bytesWritten = PR_Write(fd, &isDirty, sizeof(isDirty));
+  PR_Close(fd);
+  if (bytesWritten != sizeof(isDirty)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+void
+CacheIndex::ReadIndexFromDisk()
+{
+  LOG(("CacheIndex::ReadIndexFromDisk()"));
+
+  nsresult rv;
+
+  sLock.AssertCurrentThreadOwns();
+  MOZ_ASSERT(mState == INITIAL);
+
+  ChangeState(READING);
+
+  mIndexFileOpener = new FileOpenHelper(this);
+  rv = CacheFileIOManager::OpenFile(NS_LITERAL_CSTRING(INDEX_NAME),
+                                    CacheFileIOManager::SPECIAL_FILE |
+                                    CacheFileIOManager::OPEN,
+                                    mIndexFileOpener);
+  if (NS_FAILED(rv)) {
+    LOG(("CacheIndex::ReadIndexFromDisk() - CacheFileIOManager::OpenFile() "
+         "failed [rv=0x%08x, file=%s]", rv, INDEX_NAME));
+    FinishRead(false);
+    return;
+  }
+
+  mJournalFileOpener = new FileOpenHelper(this);
+  rv = CacheFileIOManager::OpenFile(NS_LITERAL_CSTRING(JOURNAL_NAME),
+                                    CacheFileIOManager::SPECIAL_FILE |
+                                    CacheFileIOManager::OPEN,
+                                    mJournalFileOpener);
+  if (NS_FAILED(rv)) {
+    LOG(("CacheIndex::ReadIndexFromDisk() - CacheFileIOManager::OpenFile() "
+         "failed [rv=0x%08x, file=%s]", rv, JOURNAL_NAME));
+    FinishRead(false);
+  }
+
+  mTmpFileOpener = new FileOpenHelper(this);
+  rv = CacheFileIOManager::OpenFile(NS_LITERAL_CSTRING(TEMP_INDEX_NAME),
+                                    CacheFileIOManager::SPECIAL_FILE |
+                                    CacheFileIOManager::OPEN,
+                                    mTmpFileOpener);
+  if (NS_FAILED(rv)) {
+    LOG(("CacheIndex::ReadIndexFromDisk() - CacheFileIOManager::OpenFile() "
+         "failed [rv=0x%08x, file=%s]", rv, TEMP_INDEX_NAME));
+    FinishRead(false);
+  }
+}
+
+void
+CacheIndex::StartReadingIndex()
+{
+  LOG(("CacheIndex::StartReadingIndex()"));
+
+  nsresult rv;
+
+  sLock.AssertCurrentThreadOwns();
+
+  MOZ_ASSERT(mIndexHandle);
+  MOZ_ASSERT(mState == READING);
+  MOZ_ASSERT(!mIndexOnDiskIsValid);
+  MOZ_ASSERT(!mDontMarkIndexClean);
+  MOZ_ASSERT(!mJournalReadSuccessfully);
+  MOZ_ASSERT(mIndexHandle->FileSize() >= 0);
+  MOZ_ASSERT(!mRWPending);
+
+  int64_t entriesSize = mIndexHandle->FileSize() - sizeof(CacheIndexHeader) -
+                        sizeof(CacheHash::Hash32_t);
+
+  if (entriesSize < 0 || entriesSize % sizeof(CacheIndexRecord)) {
+    LOG(("CacheIndex::StartReadingIndex() - Index is corrupted"));
+    FinishRead(false);
+    return;
+  }
+
+  AllocBuffer();
+  mSkipEntries = 0;
+  mRWHash = new CacheHash();
+
+  mRWBufPos = std::min(mRWBufSize,
+                       static_cast<uint32_t>(mIndexHandle->FileSize()));
+
+  rv = CacheFileIOManager::Read(mIndexHandle, 0, mRWBuf, mRWBufPos, this);
+  if (NS_FAILED(rv)) {
+    LOG(("CacheIndex::StartReadingIndex() - CacheFileIOManager::Read() failed "
+         "synchronously [rv=0x%08x]", rv));
+    FinishRead(false);
+  } else {
+    mRWPending = true;
+  }
+}
+
+void
+CacheIndex::ParseRecords()
+{
+  LOG(("CacheIndex::ParseRecords()"));
+
+  nsresult rv;
+
+  sLock.AssertCurrentThreadOwns();
+
+  MOZ_ASSERT(!mRWPending);
+
+  uint32_t entryCnt = (mIndexHandle->FileSize() - sizeof(CacheIndexHeader) -
+                     sizeof(CacheHash::Hash32_t)) / sizeof(CacheIndexRecord);
+  uint32_t pos = 0;
+
+  if (!mSkipEntries) {
+    if (NetworkEndian::readUint32(mRWBuf + pos) != kIndexVersion) {
+      FinishRead(false);
+      return;
+    }
+    pos += sizeof(uint32_t);
+
+    mIndexTimeStamp = NetworkEndian::readUint32(mRWBuf + pos);
+    pos += sizeof(uint32_t);
+
+    if (NetworkEndian::readUint32(mRWBuf + pos)) {
+      if (mJournalHandle) {
+        CacheFileIOManager::DoomFile(mJournalHandle, nullptr);
+        mJournalHandle = nullptr;
+      }
+    } else {
+      uint32_t * isDirty = reinterpret_cast<uint32_t *>(
+                             moz_xmalloc(sizeof(uint32_t)));
+      NetworkEndian::writeUint32(isDirty, 1);
+
+      // Mark index dirty. The buffer is freed by CacheFileIOManager when
+      // nullptr is passed as the listener and the call doesn't fail
+      // synchronously.
+      rv = CacheFileIOManager::Write(mIndexHandle, 2 * sizeof(uint32_t),
+                                     reinterpret_cast<char *>(isDirty),
+                                     sizeof(uint32_t), true, false, nullptr);
+      if (NS_FAILED(rv)) {
+        // This is not fatal, just free the memory
+        free(isDirty);
+      }
+    }
+    pos += sizeof(uint32_t);
+  }
+
+  uint32_t hashOffset = pos;
+
+  while (pos + sizeof(CacheIndexRecord) <= mRWBufPos &&
+         mSkipEntries != entryCnt) {
+    CacheIndexRecord *rec = reinterpret_cast<CacheIndexRecord *>(mRWBuf + pos);
+    CacheIndexEntry tmpEntry(&rec->mHash);
+    tmpEntry.ReadFromBuf(mRWBuf + pos);
+
+    if (tmpEntry.IsDirty() || !tmpEntry.IsInitialized() ||
+        tmpEntry.IsFileEmpty() || tmpEntry.IsFresh() || tmpEntry.IsRemoved()) {
+      LOG(("CacheIndex::ParseRecords() - Invalid entry found in index, removing"
+           " whole index [dirty=%d, initialized=%d, fileEmpty=%d, fresh=%d, "
+           "removed=%d]", tmpEntry.IsDirty(), tmpEntry.IsInitialized(),
+           tmpEntry.IsFileEmpty(), tmpEntry.IsFresh(), tmpEntry.IsRemoved()));
+      FinishRead(false);
+      return;
+    }
+
+    CacheIndexEntryAutoManage emng(tmpEntry.Hash(), this);
+
+    CacheIndexEntry *entry = mIndex.PutEntry(*tmpEntry.Hash());
+    *entry = tmpEntry;
+
+    pos += sizeof(CacheIndexRecord);
+    mSkipEntries++;
+  }
+
+  mRWHash->Update(mRWBuf + hashOffset, pos - hashOffset);
+
+  if (pos != mRWBufPos) {
+    memmove(mRWBuf, mRWBuf + pos, mRWBufPos - pos);
+  }
+
+  mRWBufPos -= pos;
+  pos = 0;
+
+  int64_t fileOffset = sizeof(CacheIndexHeader) +
+                       mSkipEntries * sizeof(CacheIndexRecord) + mRWBufPos;
+
+  MOZ_ASSERT(fileOffset <= mIndexHandle->FileSize());
+  if (fileOffset == mIndexHandle->FileSize()) {
+    uint32_t expectedHash = NetworkEndian::readUint32(mRWBuf);
+    if (mRWHash->GetHash() != expectedHash) {
+      LOG(("CacheIndex::ParseRecords() - Hash mismatch, [is %x, should be %x]",
+           mRWHash->GetHash(), expectedHash));
+      FinishRead(false);
+      return;
+    }
+
+    mIndexOnDiskIsValid = true;
+    mJournalReadSuccessfully = false;
+
+    if (mJournalHandle) {
+      StartReadingJournal();
+    } else {
+      FinishRead(false);
+    }
+
+    return;
+  }
+
+  pos = mRWBufPos;
+  uint32_t toRead = std::min(mRWBufSize - pos,
+                             static_cast<uint32_t>(mIndexHandle->FileSize() -
+                                                   fileOffset));
+  mRWBufPos = pos + toRead;
+
+  rv = CacheFileIOManager::Read(mIndexHandle, fileOffset, mRWBuf + pos, toRead,
+                                this);
+  if (NS_FAILED(rv)) {
+    LOG(("CacheIndex::ParseRecords() - CacheFileIOManager::Read() failed "
+         "synchronously [rv=0x%08x]", rv));
+    FinishRead(false);
+    return;
+  } else {
+    mRWPending = true;
+  }
+}
+
+void
+CacheIndex::StartReadingJournal()
+{
+  LOG(("CacheIndex::StartReadingJournal()"));
+
+  nsresult rv;
+
+  sLock.AssertCurrentThreadOwns();
+
+  MOZ_ASSERT(mJournalHandle);
+  MOZ_ASSERT(mIndexOnDiskIsValid);
+  MOZ_ASSERT(mTmpJournal.Count() == 0);
+  MOZ_ASSERT(mJournalHandle->FileSize() >= 0);
+  MOZ_ASSERT(!mRWPending);
+
+  int64_t entriesSize = mJournalHandle->FileSize() -
+                        sizeof(CacheHash::Hash32_t);
+
+  if (entriesSize < 0 || entriesSize % sizeof(CacheIndexRecord)) {
+    LOG(("CacheIndex::StartReadingJournal() - Journal is corrupted"));
+    FinishRead(false);
+    return;
+  }
+
+  mSkipEntries = 0;
+  mRWHash = new CacheHash();
+
+  mRWBufPos = std::min(mRWBufSize,
+                       static_cast<uint32_t>(mJournalHandle->FileSize()));
+
+  rv = CacheFileIOManager::Read(mJournalHandle, 0, mRWBuf, mRWBufPos, this);
+  if (NS_FAILED(rv)) {
+    LOG(("CacheIndex::StartReadingJournal() - CacheFileIOManager::Read() failed"
+         " synchronously [rv=0x%08x]", rv));
+    FinishRead(false);
+  } else {
+    mRWPending = true;
+  }
+}
+
+void
+CacheIndex::ParseJournal()
+{
+  LOG(("CacheIndex::ParseJournal()"));
+
+  nsresult rv;
+
+  sLock.AssertCurrentThreadOwns();
+
+  MOZ_ASSERT(!mRWPending);
+
+  uint32_t entryCnt = (mJournalHandle->FileSize() -
+                       sizeof(CacheHash::Hash32_t)) / sizeof(CacheIndexRecord);
+
+  uint32_t pos = 0;
+
+  while (pos + sizeof(CacheIndexRecord) <= mRWBufPos &&
+         mSkipEntries != entryCnt) {
+    CacheIndexEntry tmpEntry(reinterpret_cast<SHA1Sum::Hash *>(mRWBuf + pos));
+    tmpEntry.ReadFromBuf(mRWBuf + pos);
+
+    CacheIndexEntry *entry = mTmpJournal.PutEntry(*tmpEntry.Hash());
+    *entry = tmpEntry;
+
+    if (entry->IsDirty() || entry->IsFresh()) {
+      LOG(("CacheIndex::ParseJournal() - Invalid entry found in journal, "
+           "ignoring whole journal [dirty=%d, fresh=%d]", entry->IsDirty(),
+           entry->IsFresh()));
+      FinishRead(false);
+      return;
+    }
+
+    pos += sizeof(CacheIndexRecord);
+    mSkipEntries++;
+  }
+
+  mRWHash->Update(mRWBuf, pos);
+
+  if (pos != mRWBufPos) {
+    memmove(mRWBuf, mRWBuf + pos, mRWBufPos - pos);
+  }
+
+  mRWBufPos -= pos;
+  pos = 0;
+
+  int64_t fileOffset = mSkipEntries * sizeof(CacheIndexRecord) + mRWBufPos;
+
+  MOZ_ASSERT(fileOffset <= mJournalHandle->FileSize());
+  if (fileOffset == mJournalHandle->FileSize()) {
+    uint32_t expectedHash = NetworkEndian::readUint32(mRWBuf);
+    if (mRWHash->GetHash() != expectedHash) {
+      LOG(("CacheIndex::ParseJournal() - Hash mismatch, [is %x, should be %x]",
+           mRWHash->GetHash(), expectedHash));
+      FinishRead(false);
+      return;
+    }
+
+    mJournalReadSuccessfully = true;
+    FinishRead(true);
+    return;
+  }
+
+  pos = mRWBufPos;
+  uint32_t toRead = std::min(mRWBufSize - pos,
+                             static_cast<uint32_t>(mJournalHandle->FileSize() -
+                                                   fileOffset));
+  mRWBufPos = pos + toRead;
+
+  rv = CacheFileIOManager::Read(mJournalHandle, fileOffset, mRWBuf + pos,
+                                toRead, this);
+  if (NS_FAILED(rv)) {
+    LOG(("CacheIndex::ParseJournal() - CacheFileIOManager::Read() failed "
+         "synchronously [rv=0x%08x]", rv));
+    FinishRead(false);
+    return;
+  } else {
+    mRWPending = true;
+  }
+}
+
+void
+CacheIndex::MergeJournal()
+{
+  LOG(("CacheIndex::MergeJournal()"));
+
+  sLock.AssertCurrentThreadOwns();
+
+  for (auto iter = mTmpJournal.Iter(); !iter.Done(); iter.Next()) {
+    CacheIndexEntry* entry = iter.Get();
+
+    LOG(("CacheIndex::MergeJournal() [hash=%08x%08x%08x%08x%08x]",
+         LOGSHA1(entry->Hash())));
+
+    CacheIndexEntry* entry2 = mIndex.GetEntry(*entry->Hash());
+    {
+      CacheIndexEntryAutoManage emng(entry->Hash(), this);
+      if (entry->IsRemoved()) {
+        if (entry2) {
+          entry2->MarkRemoved();
+          entry2->MarkDirty();
+        }
+      } else {
+        if (!entry2) {
+          entry2 = mIndex.PutEntry(*entry->Hash());
+        }
+
+        *entry2 = *entry;
+        entry2->MarkDirty();
+      }
+    }
+    iter.Remove();
+  }
+
+  MOZ_ASSERT(mTmpJournal.Count() == 0);
+}
+
+void
+CacheIndex::EnsureNoFreshEntry()
+{
+#ifdef DEBUG_STATS
+  CacheIndexStats debugStats;
+  debugStats.DisableLogging();
+  for (auto iter = mIndex.Iter(); !iter.Done(); iter.Next()) {
+    debugStats.BeforeChange(nullptr);
+    debugStats.AfterChange(iter.Get());
+  }
+  MOZ_ASSERT(debugStats.Fresh() == 0);
+#endif
+}
+
+void
+CacheIndex::EnsureCorrectStats()
+{
+#ifdef DEBUG_STATS
+  MOZ_ASSERT(mPendingUpdates.Count() == 0);
+  CacheIndexStats debugStats;
+  debugStats.DisableLogging();
+  for (auto iter = mIndex.Iter(); !iter.Done(); iter.Next()) {
+    debugStats.BeforeChange(nullptr);
+    debugStats.AfterChange(iter.Get());
+  }
+  MOZ_ASSERT(debugStats == mIndexStats);
+#endif
+}
+
+void
+CacheIndex::FinishRead(bool aSucceeded)
+{
+  LOG(("CacheIndex::FinishRead() [succeeded=%d]", aSucceeded));
+  sLock.AssertCurrentThreadOwns();
+
+  MOZ_ASSERT((!aSucceeded && mState == SHUTDOWN) || mState == READING);
+
+  MOZ_ASSERT(
+    // -> rebuild
+    (!aSucceeded && !mIndexOnDiskIsValid && !mJournalReadSuccessfully) ||
+    // -> update
+    (!aSucceeded && mIndexOnDiskIsValid && !mJournalReadSuccessfully) ||
+    // -> ready
+    (aSucceeded && mIndexOnDiskIsValid && mJournalReadSuccessfully));
+
+  // If there is read operation pending we must be cancelling reading of the
+  // index when shutting down or removing the whole index.
+  MOZ_ASSERT(!mRWPending || (!aSucceeded && (mShuttingDown || mRemovingAll)));
+
+  if (mState == SHUTDOWN) {
+    RemoveFile(NS_LITERAL_CSTRING(TEMP_INDEX_NAME));
+    RemoveFile(NS_LITERAL_CSTRING(JOURNAL_NAME));
+  } else {
+    if (mIndexHandle && !mIndexOnDiskIsValid) {
+      CacheFileIOManager::DoomFile(mIndexHandle, nullptr);
+    }
+
+    if (mJournalHandle) {
+      CacheFileIOManager::DoomFile(mJournalHandle, nullptr);
+    }
+  }
+
+  if (mIndexFileOpener) {
+    mIndexFileOpener->Cancel();
+    mIndexFileOpener = nullptr;
+  }
+  if (mJournalFileOpener) {
+    mJournalFileOpener->Cancel();
+    mJournalFileOpener = nullptr;
+  }
+  if (mTmpFileOpener) {
+    mTmpFileOpener->Cancel();
+    mTmpFileOpener = nullptr;
+  }
+
+  mIndexHandle = nullptr;
+  mJournalHandle = nullptr;
+  mRWHash = nullptr;
+  ReleaseBuffer();
+
+  if (mState == SHUTDOWN) {
+    return;
+  }
+
+  if (!mIndexOnDiskIsValid) {
+    MOZ_ASSERT(mTmpJournal.Count() == 0);
+    EnsureNoFreshEntry();
+    ProcessPendingOperations();
+    // Remove all entries that we haven't seen during this session
+    RemoveNonFreshEntries();
+    StartUpdatingIndex(true);
+    return;
+  }
+
+  if (!mJournalReadSuccessfully) {
+    mTmpJournal.Clear();
+    EnsureNoFreshEntry();
+    ProcessPendingOperations();
+    StartUpdatingIndex(false);
+    return;
+  }
+
+  MergeJournal();
+  EnsureNoFreshEntry();
+  ProcessPendingOperations();
+  mIndexStats.Log();
+
+  ChangeState(READY);
+  mLastDumpTime = TimeStamp::NowLoRes(); // Do not dump new index immediately
+}
+
+// static
+void
+CacheIndex::DelayedUpdate(nsITimer *aTimer, void *aClosure)
+{
+  LOG(("CacheIndex::DelayedUpdate()"));
+
+  StaticMutexAutoLock lock(sLock);
+  RefPtr<CacheIndex> index = gInstance;
+
+  if (!index) {
+    return;
+  }
+
+  index->DelayedUpdateLocked();
+}
+
+// static
+void
+CacheIndex::DelayedUpdateLocked()
+{
+  LOG(("CacheIndex::DelayedUpdateLocked()"));
+
+  sLock.AssertCurrentThreadOwns();
+
+  nsresult rv;
+
+  mUpdateTimer = nullptr;
+
+  if (!IsIndexUsable()) {
+    return;
+  }
+
+  if (mState == READY && mShuttingDown) {
+    return;
+  }
+
+  // mUpdateEventPending must be false here since StartUpdatingIndex() won't
+  // schedule timer if it is true.
+  MOZ_ASSERT(!mUpdateEventPending);
+  if (mState != BUILDING && mState != UPDATING) {
+    LOG(("CacheIndex::DelayedUpdateLocked() - Update was canceled"));
+    return;
+  }
+
+  // We need to redispatch to run with lower priority
+  RefPtr<CacheIOThread> ioThread = CacheFileIOManager::IOThread();
+  MOZ_ASSERT(ioThread);
+
+  mUpdateEventPending = true;
+  rv = ioThread->Dispatch(this, CacheIOThread::INDEX);
+  if (NS_FAILED(rv)) {
+    mUpdateEventPending = false;
+    NS_WARNING("CacheIndex::DelayedUpdateLocked() - Can't dispatch event");
+    LOG(("CacheIndex::DelayedUpdate() - Can't dispatch event" ));
+    FinishUpdate(false);
+  }
+}
+
+nsresult
+CacheIndex::ScheduleUpdateTimer(uint32_t aDelay)
+{
+  LOG(("CacheIndex::ScheduleUpdateTimer() [delay=%u]", aDelay));
+
+  MOZ_ASSERT(!mUpdateTimer);
+
+  nsresult rv;
+
+  nsCOMPtr<nsITimer> timer = do_CreateInstance("@mozilla.org/timer;1", &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIEventTarget> ioTarget = CacheFileIOManager::IOTarget();
+  MOZ_ASSERT(ioTarget);
+
+  rv = timer->SetTarget(ioTarget);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = timer->InitWithFuncCallback(CacheIndex::DelayedUpdate, nullptr,
+                                   aDelay, nsITimer::TYPE_ONE_SHOT);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  mUpdateTimer.swap(timer);
+  return NS_OK;
+}
+
+nsresult
+CacheIndex::SetupDirectoryEnumerator()
+{
+  MOZ_ASSERT(!NS_IsMainThread());
+  MOZ_ASSERT(!mDirEnumerator);
+
+  nsresult rv;
+  nsCOMPtr<nsIFile> file;
+
+  rv = mCacheDirectory->Clone(getter_AddRefs(file));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = file->AppendNative(NS_LITERAL_CSTRING(ENTRIES_DIR));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool exists;
+  rv = file->Exists(&exists);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (!exists) {
+    NS_WARNING("CacheIndex::SetupDirectoryEnumerator() - Entries directory "
+               "doesn't exist!");
+    LOG(("CacheIndex::SetupDirectoryEnumerator() - Entries directory doesn't "
+          "exist!" ));
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsCOMPtr<nsISimpleEnumerator> enumerator;
+  rv = file->GetDirectoryEntries(getter_AddRefs(enumerator));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  mDirEnumerator = do_QueryInterface(enumerator, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+void
+CacheIndex::InitEntryFromDiskData(CacheIndexEntry *aEntry,
+                                  CacheFileMetadata *aMetaData,
+                                  int64_t aFileSize)
+{
+  aEntry->InitNew();
+  aEntry->MarkDirty();
+  aEntry->MarkFresh();
+
+  aEntry->Init(GetOriginAttrsHash(aMetaData->OriginAttributes()),
+               aMetaData->IsAnonymous(),
+               aMetaData->Pinned());
+
+  uint32_t expirationTime;
+  aMetaData->GetExpirationTime(&expirationTime);
+  aEntry->SetExpirationTime(expirationTime);
+
+  uint32_t frecency;
+  aMetaData->GetFrecency(&frecency);
+  aEntry->SetFrecency(frecency);
+
+  aEntry->SetFileSize(static_cast<uint32_t>(
+                        std::min(static_cast<int64_t>(PR_UINT32_MAX),
+                                 (aFileSize + 0x3FF) >> 10)));
+}
+
+bool
+CacheIndex::IsUpdatePending()
+{
+  sLock.AssertCurrentThreadOwns();
+
+  if (mUpdateTimer || mUpdateEventPending) {
+    return true;
+  }
+
+  return false;
+}
+
+void
+CacheIndex::BuildIndex()
+{
+  LOG(("CacheIndex::BuildIndex()"));
+
+  sLock.AssertCurrentThreadOwns();
+
+  MOZ_ASSERT(mPendingUpdates.Count() == 0);
+
+  nsresult rv;
+
+  if (!mDirEnumerator) {
+    {
+      // Do not do IO under the lock.
+      StaticMutexAutoUnlock unlock(sLock);
+      rv = SetupDirectoryEnumerator();
+    }
+    if (mState == SHUTDOWN) {
+      // The index was shut down while we released the lock. FinishUpdate() was
+      // already called from Shutdown(), so just simply return here.
+      return;
+    }
+
+    if (NS_FAILED(rv)) {
+      FinishUpdate(false);
+      return;
+    }
+  }
+
+  while (true) {
+    if (CacheIOThread::YieldAndRerun()) {
+      LOG(("CacheIndex::BuildIndex() - Breaking loop for higher level events."));
+      mUpdateEventPending = true;
+      return;
+    }
+
+    nsCOMPtr<nsIFile> file;
+    {
+      // Do not do IO under the lock.
+      StaticMutexAutoUnlock unlock(sLock);
+      rv = mDirEnumerator->GetNextFile(getter_AddRefs(file));
+    }
+    if (mState == SHUTDOWN) {
+      return;
+    }
+    if (!file) {
+      FinishUpdate(NS_SUCCEEDED(rv));
+      return;
+    }
+
+    nsAutoCString leaf;
+    rv = file->GetNativeLeafName(leaf);
+    if (NS_FAILED(rv)) {
+      LOG(("CacheIndex::BuildIndex() - GetNativeLeafName() failed! Skipping "
+           "file."));
+      mDontMarkIndexClean = true;
+      continue;
+    }
+
+    SHA1Sum::Hash hash;
+    rv = CacheFileIOManager::StrToHash(leaf, &hash);
+    if (NS_FAILED(rv)) {
+      LOG(("CacheIndex::BuildIndex() - Filename is not a hash, removing file. "
+           "[name=%s]", leaf.get()));
+      file->Remove(false);
+      continue;
+    }
+
+    CacheIndexEntry *entry = mIndex.GetEntry(hash);
+    if (entry && entry->IsRemoved()) {
+      LOG(("CacheIndex::BuildIndex() - Found file that should not exist. "
+           "[name=%s]", leaf.get()));
+      entry->Log();
+      MOZ_ASSERT(entry->IsFresh());
+      entry = nullptr;
+    }
+
+#ifdef DEBUG
+    RefPtr<CacheFileHandle> handle;
+    CacheFileIOManager::gInstance->mHandles.GetHandle(&hash,
+                                                      getter_AddRefs(handle));
+#endif
+
+    if (entry) {
+      // the entry is up to date
+      LOG(("CacheIndex::BuildIndex() - Skipping file because the entry is up to"
+           " date. [name=%s]", leaf.get()));
+      entry->Log();
+      MOZ_ASSERT(entry->IsFresh()); // The entry must be from this session
+      // there must be an active CacheFile if the entry is not initialized
+      MOZ_ASSERT(entry->IsInitialized() || handle);
+      continue;
+    }
+
+    MOZ_ASSERT(!handle);
+
+    RefPtr<CacheFileMetadata> meta = new CacheFileMetadata();
+    int64_t size = 0;
+
+    {
+      // Do not do IO under the lock.
+      StaticMutexAutoUnlock unlock(sLock);
+      rv = meta->SyncReadMetadata(file);
+
+      if (NS_SUCCEEDED(rv)) {
+        rv = file->GetFileSize(&size);
+        if (NS_FAILED(rv)) {
+          LOG(("CacheIndex::BuildIndex() - Cannot get filesize of file that was"
+               " successfully parsed. [name=%s]", leaf.get()));
+        }
+      }
+    }
+    if (mState == SHUTDOWN) {
+      return;
+    }
+
+    // Nobody could add the entry while the lock was released since we modify
+    // the index only on IO thread and this loop is executed on IO thread too.
+    entry = mIndex.GetEntry(hash);
+    MOZ_ASSERT(!entry || entry->IsRemoved());
+
+    if (NS_FAILED(rv)) {
+      LOG(("CacheIndex::BuildIndex() - CacheFileMetadata::SyncReadMetadata() "
+           "failed, removing file. [name=%s]", leaf.get()));
+      file->Remove(false);
+    } else {
+      CacheIndexEntryAutoManage entryMng(&hash, this);
+      entry = mIndex.PutEntry(hash);
+      InitEntryFromDiskData(entry, meta, size);
+      LOG(("CacheIndex::BuildIndex() - Added entry to index. [hash=%s]",
+           leaf.get()));
+      entry->Log();
+    }
+  }
+
+  NS_NOTREACHED("We should never get here");
+}
+
+bool
+CacheIndex::StartUpdatingIndexIfNeeded(bool aSwitchingToReadyState)
+{
+  // Start updating process when we are in or we are switching to READY state
+  // and index needs update, but not during shutdown or when removing all
+  // entries.
+  if ((mState == READY || aSwitchingToReadyState) && mIndexNeedsUpdate &&
+      !mShuttingDown && !mRemovingAll) {
+    LOG(("CacheIndex::StartUpdatingIndexIfNeeded() - starting update process"));
+    mIndexNeedsUpdate = false;
+    StartUpdatingIndex(false);
+    return true;
+  }
+
+  return false;
+}
+
+void
+CacheIndex::StartUpdatingIndex(bool aRebuild)
+{
+  LOG(("CacheIndex::StartUpdatingIndex() [rebuild=%d]", aRebuild));
+
+  sLock.AssertCurrentThreadOwns();
+
+  nsresult rv;
+
+  mIndexStats.Log();
+
+  ChangeState(aRebuild ? BUILDING : UPDATING);
+  mDontMarkIndexClean = false;
+
+  if (mShuttingDown || mRemovingAll) {
+    FinishUpdate(false);
+    return;
+  }
+
+  if (IsUpdatePending()) {
+    LOG(("CacheIndex::StartUpdatingIndex() - Update is already pending"));
+    return;
+  }
+
+  uint32_t elapsed = (TimeStamp::NowLoRes() - mStartTime).ToMilliseconds();
+  if (elapsed < kUpdateIndexStartDelay) {
+    LOG(("CacheIndex::StartUpdatingIndex() - %u ms elapsed since startup, "
+         "scheduling timer to fire in %u ms.", elapsed,
+         kUpdateIndexStartDelay - elapsed));
+    rv = ScheduleUpdateTimer(kUpdateIndexStartDelay - elapsed);
+    if (NS_SUCCEEDED(rv)) {
+      return;
+    }
+
+    LOG(("CacheIndex::StartUpdatingIndex() - ScheduleUpdateTimer() failed. "
+         "Starting update immediately."));
+  } else {
+    LOG(("CacheIndex::StartUpdatingIndex() - %u ms elapsed since startup, "
+         "starting update now.", elapsed));
+  }
+
+  RefPtr<CacheIOThread> ioThread = CacheFileIOManager::IOThread();
+  MOZ_ASSERT(ioThread);
+
+  // We need to dispatch an event even if we are on IO thread since we need to
+  // update the index with the correct priority.
+  mUpdateEventPending = true;
+  rv = ioThread->Dispatch(this, CacheIOThread::INDEX);
+  if (NS_FAILED(rv)) {
+    mUpdateEventPending = false;
+    NS_WARNING("CacheIndex::StartUpdatingIndex() - Can't dispatch event");
+    LOG(("CacheIndex::StartUpdatingIndex() - Can't dispatch event" ));
+    FinishUpdate(false);
+  }
+}
+
+void
+CacheIndex::UpdateIndex()
+{
+  LOG(("CacheIndex::UpdateIndex()"));
+
+  sLock.AssertCurrentThreadOwns();
+
+  MOZ_ASSERT(mPendingUpdates.Count() == 0);
+
+  nsresult rv;
+
+  if (!mDirEnumerator) {
+    {
+      // Do not do IO under the lock.
+      StaticMutexAutoUnlock unlock(sLock);
+      rv = SetupDirectoryEnumerator();
+    }
+    if (mState == SHUTDOWN) {
+      // The index was shut down while we released the lock. FinishUpdate() was
+      // already called from Shutdown(), so just simply return here.
+      return;
+    }
+
+    if (NS_FAILED(rv)) {
+      FinishUpdate(false);
+      return;
+    }
+  }
+
+  while (true) {
+    if (CacheIOThread::YieldAndRerun()) {
+      LOG(("CacheIndex::UpdateIndex() - Breaking loop for higher level "
+           "events."));
+      mUpdateEventPending = true;
+      return;
+    }
+
+    nsCOMPtr<nsIFile> file;
+    {
+      // Do not do IO under the lock.
+      StaticMutexAutoUnlock unlock(sLock);
+      rv = mDirEnumerator->GetNextFile(getter_AddRefs(file));
+    }
+    if (mState == SHUTDOWN) {
+      return;
+    }
+    if (!file) {
+      FinishUpdate(NS_SUCCEEDED(rv));
+      return;
+    }
+
+    nsAutoCString leaf;
+    rv = file->GetNativeLeafName(leaf);
+    if (NS_FAILED(rv)) {
+      LOG(("CacheIndex::UpdateIndex() - GetNativeLeafName() failed! Skipping "
+           "file."));
+      mDontMarkIndexClean = true;
+      continue;
+    }
+
+    SHA1Sum::Hash hash;
+    rv = CacheFileIOManager::StrToHash(leaf, &hash);
+    if (NS_FAILED(rv)) {
+      LOG(("CacheIndex::UpdateIndex() - Filename is not a hash, removing file. "
+           "[name=%s]", leaf.get()));
+      file->Remove(false);
+      continue;
+    }
+
+    CacheIndexEntry *entry = mIndex.GetEntry(hash);
+    if (entry && entry->IsRemoved()) {
+      if (entry->IsFresh()) {
+        LOG(("CacheIndex::UpdateIndex() - Found file that should not exist. "
+             "[name=%s]", leaf.get()));
+        entry->Log();
+      }
+      entry = nullptr;
+    }
+
+#ifdef DEBUG
+    RefPtr<CacheFileHandle> handle;
+    CacheFileIOManager::gInstance->mHandles.GetHandle(&hash,
+                                                      getter_AddRefs(handle));
+#endif
+
+    if (entry && entry->IsFresh()) {
+      // the entry is up to date
+      LOG(("CacheIndex::UpdateIndex() - Skipping file because the entry is up "
+           " to date. [name=%s]", leaf.get()));
+      entry->Log();
+      // there must be an active CacheFile if the entry is not initialized
+      MOZ_ASSERT(entry->IsInitialized() || handle);
+      continue;
+    }
+
+    MOZ_ASSERT(!handle);
+
+    if (entry) {
+      PRTime lastModifiedTime;
+      {
+        // Do not do IO under the lock.
+        StaticMutexAutoUnlock unlock(sLock);
+        rv = file->GetLastModifiedTime(&lastModifiedTime);
+      }
+      if (mState == SHUTDOWN) {
+        return;
+      }
+      if (NS_FAILED(rv)) {
+        LOG(("CacheIndex::UpdateIndex() - Cannot get lastModifiedTime. "
+             "[name=%s]", leaf.get()));
+        // Assume the file is newer than index
+      } else {
+        if (mIndexTimeStamp > (lastModifiedTime / PR_MSEC_PER_SEC)) {
+          LOG(("CacheIndex::UpdateIndex() - Skipping file because of last "
+               "modified time. [name=%s, indexTimeStamp=%u, "
+               "lastModifiedTime=%u]", leaf.get(), mIndexTimeStamp,
+               lastModifiedTime / PR_MSEC_PER_SEC));
+
+          CacheIndexEntryAutoManage entryMng(&hash, this);
+          entry->MarkFresh();
+          continue;
+        }
+      }
+    }
+
+    RefPtr<CacheFileMetadata> meta = new CacheFileMetadata();
+    int64_t size = 0;
+
+    {
+      // Do not do IO under the lock.
+      StaticMutexAutoUnlock unlock(sLock);
+      rv = meta->SyncReadMetadata(file);
+
+      if (NS_SUCCEEDED(rv)) {
+        rv = file->GetFileSize(&size);
+        if (NS_FAILED(rv)) {
+          LOG(("CacheIndex::UpdateIndex() - Cannot get filesize of file that "
+               "was successfully parsed. [name=%s]", leaf.get()));
+        }
+      }
+    }
+    if (mState == SHUTDOWN) {
+      return;
+    }
+
+    // Nobody could add the entry while the lock was released since we modify
+    // the index only on IO thread and this loop is executed on IO thread too.
+    entry = mIndex.GetEntry(hash);
+    MOZ_ASSERT(!entry || !entry->IsFresh());
+
+    CacheIndexEntryAutoManage entryMng(&hash, this);
+
+    if (NS_FAILED(rv)) {
+      LOG(("CacheIndex::UpdateIndex() - CacheFileMetadata::SyncReadMetadata() "
+           "failed, removing file. [name=%s]", leaf.get()));
+      file->Remove(false);
+      if (entry) {
+        entry->MarkRemoved();
+        entry->MarkFresh();
+        entry->MarkDirty();
+      }
+    } else {
+      entry = mIndex.PutEntry(hash);
+      InitEntryFromDiskData(entry, meta, size);
+      LOG(("CacheIndex::UpdateIndex() - Added/updated entry to/in index. "
+           "[hash=%s]", leaf.get()));
+      entry->Log();
+    }
+  }
+
+  NS_NOTREACHED("We should never get here");
+}
+
+void
+CacheIndex::FinishUpdate(bool aSucceeded)
+{
+  LOG(("CacheIndex::FinishUpdate() [succeeded=%d]", aSucceeded));
+
+  MOZ_ASSERT(mState == UPDATING || mState == BUILDING ||
+             (!aSucceeded && mState == SHUTDOWN));
+
+  sLock.AssertCurrentThreadOwns();
+
+  if (mDirEnumerator) {
+    if (NS_IsMainThread()) {
+      LOG(("CacheIndex::FinishUpdate() - posting of PreShutdownInternal failed?"
+           " Cannot safely release mDirEnumerator, leaking it!"));
+      NS_WARNING(("CacheIndex::FinishUpdate() - Leaking mDirEnumerator!"));
+      // This can happen only in case dispatching event to IO thread failed in
+      // CacheIndex::PreShutdown().
+      Unused << mDirEnumerator.forget(); // Leak it since dir enumerator is not threadsafe
+    } else {
+      mDirEnumerator->Close();
+      mDirEnumerator = nullptr;
+    }
+  }
+
+  if (!aSucceeded) {
+    mDontMarkIndexClean = true;
+  }
+
+  if (mState == SHUTDOWN) {
+    return;
+  }
+
+  if (mState == UPDATING && aSucceeded) {
+    // If we've iterated over all entries successfully then all entries that
+    // really exist on the disk are now marked as fresh. All non-fresh entries
+    // don't exist anymore and must be removed from the index.
+    RemoveNonFreshEntries();
+  }
+
+  // Make sure we won't start update. If the build or update failed, there is no
+  // reason to believe that it will succeed next time.
+  mIndexNeedsUpdate = false;
+
+  ChangeState(READY);
+  mLastDumpTime = TimeStamp::NowLoRes(); // Do not dump new index immediately
+}
+
+void
+CacheIndex::RemoveNonFreshEntries()
+{
+  for (auto iter = mIndex.Iter(); !iter.Done(); iter.Next()) {
+    CacheIndexEntry* entry = iter.Get();
+    if (entry->IsFresh()) {
+      continue;
+    }
+
+    LOG(("CacheIndex::RemoveNonFreshEntries() - Removing entry. "
+         "[hash=%08x%08x%08x%08x%08x]", LOGSHA1(entry->Hash())));
+
+    {
+      CacheIndexEntryAutoManage emng(entry->Hash(), this);
+      emng.DoNotSearchInIndex();
+    }
+
+    iter.Remove();
+  }
+}
+
+// static
+char const *
+CacheIndex::StateString(EState aState)
+{
+  switch (aState) {
+    case INITIAL:  return "INITIAL";
+    case READING:  return "READING";
+    case WRITING:  return "WRITING";
+    case BUILDING: return "BUILDING";
+    case UPDATING: return "UPDATING";
+    case READY:    return "READY";
+    case SHUTDOWN: return "SHUTDOWN";
+  }
+
+  MOZ_ASSERT(false, "Unexpected state!");
+  return "?";
+}
+
+void
+CacheIndex::ChangeState(EState aNewState)
+{
+  LOG(("CacheIndex::ChangeState() changing state %s -> %s", StateString(mState),
+       StateString(aNewState)));
+
+  // All pending updates should be processed before changing state
+  MOZ_ASSERT(mPendingUpdates.Count() == 0);
+
+  // PreShutdownInternal() should change the state to READY from every state. It
+  // may go through different states, but once we are in READY state the only
+  // possible transition is to SHUTDOWN state.
+  MOZ_ASSERT(!mShuttingDown || mState != READY || aNewState == SHUTDOWN);
+
+  // Start updating process when switching to READY state if needed
+  if (aNewState == READY && StartUpdatingIndexIfNeeded(true)) {
+    return;
+  }
+
+  if ((mState == READING || mState == BUILDING || mState == UPDATING) &&
+      aNewState == READY) {
+    ReportHashStats();
+  }
+
+  // Try to evict entries over limit everytime we're leaving state READING,
+  // BUILDING or UPDATING, but not during shutdown or when removing all
+  // entries.
+  if (!mShuttingDown && !mRemovingAll && aNewState != SHUTDOWN &&
+      (mState == READING || mState == BUILDING || mState == UPDATING))  {
+    CacheFileIOManager::EvictIfOverLimit();
+  }
+
+  mState = aNewState;
+
+  if (mState != SHUTDOWN) {
+    CacheFileIOManager::CacheIndexStateChanged();
+  }
+
+  NotifyAsyncGetDiskConsumptionCallbacks();
+}
+
+void
+CacheIndex::NotifyAsyncGetDiskConsumptionCallbacks()
+{
+  if ((mState == READY || mState == WRITING) && !mAsyncGetDiskConsumptionBlocked && mDiskConsumptionObservers.Length()) {
+    for (uint32_t i = 0; i < mDiskConsumptionObservers.Length(); ++i) {
+      DiskConsumptionObserver* o = mDiskConsumptionObservers[i];
+      // Safe to call under the lock.  We always post to the main thread.
+      o->OnDiskConsumption(mIndexStats.Size() << 10);
+    }
+
+    mDiskConsumptionObservers.Clear();
+  }
+}
+
+void
+CacheIndex::AllocBuffer()
+{
+  switch (mState) {
+    case WRITING:
+      mRWBufSize = sizeof(CacheIndexHeader) + sizeof(CacheHash::Hash32_t) +
+                   mProcessEntries * sizeof(CacheIndexRecord);
+      if (mRWBufSize > kMaxBufSize) {
+        mRWBufSize = kMaxBufSize;
+      }
+      break;
+    case READING:
+      mRWBufSize = kMaxBufSize;
+      break;
+    default:
+      MOZ_ASSERT(false, "Unexpected state!");
+  }
+
+  mRWBuf = static_cast<char *>(moz_xmalloc(mRWBufSize));
+}
+
+void
+CacheIndex::ReleaseBuffer()
+{
+  sLock.AssertCurrentThreadOwns();
+
+  if (!mRWBuf || mRWPending) {
+    return;
+  }
+
+  LOG(("CacheIndex::ReleaseBuffer() releasing buffer"));
+
+  free(mRWBuf);
+  mRWBuf = nullptr;
+  mRWBufSize = 0;
+  mRWBufPos = 0;
+}
+
+void
+CacheIndex::FrecencyArray::AppendRecord(CacheIndexRecord *aRecord)
+{
+  LOG(("CacheIndex::FrecencyArray::AppendRecord() [record=%p, hash=%08x%08x%08x"
+       "%08x%08x]", aRecord, LOGSHA1(aRecord->mHash)));
+
+  MOZ_ASSERT(!mRecs.Contains(aRecord));
+  mRecs.AppendElement(aRecord);
+
+  // If the new frecency is 0, the element should be at the end of the array,
+  // i.e. this change doesn't affect order of the array
+  if (aRecord->mFrecency != 0) {
+    ++mUnsortedElements;
+  }
+}
+
+void
+CacheIndex::FrecencyArray::RemoveRecord(CacheIndexRecord *aRecord)
+{
+  LOG(("CacheIndex::FrecencyArray::RemoveRecord() [record=%p]", aRecord));
+
+  decltype(mRecs)::index_type idx;
+  idx = mRecs.IndexOf(aRecord);
+  MOZ_RELEASE_ASSERT(idx != mRecs.NoIndex);
+  mRecs[idx] = nullptr;
+  ++mRemovedElements;
+
+  // Calling SortIfNeeded ensures that we get rid of removed elements in the
+  // array once we hit the limit.
+  SortIfNeeded();
+}
+
+void
+CacheIndex::FrecencyArray::ReplaceRecord(CacheIndexRecord *aOldRecord,
+                                         CacheIndexRecord *aNewRecord)
+{
+  LOG(("CacheIndex::FrecencyArray::ReplaceRecord() [oldRecord=%p, "
+       "newRecord=%p]", aOldRecord, aNewRecord));
+
+  decltype(mRecs)::index_type idx;
+  idx = mRecs.IndexOf(aOldRecord);
+  MOZ_RELEASE_ASSERT(idx != mRecs.NoIndex);
+  mRecs[idx] = aNewRecord;
+}
+
+void
+CacheIndex::FrecencyArray::SortIfNeeded()
+{
+  const uint32_t kMaxUnsortedCount = 512;
+  const uint32_t kMaxUnsortedPercent = 10;
+  const uint32_t kMaxRemovedCount = 512;
+
+  uint32_t unsortedLimit =
+    std::min<uint32_t>(kMaxUnsortedCount, Length() * kMaxUnsortedPercent / 100);
+
+  if (mUnsortedElements > unsortedLimit ||
+      mRemovedElements > kMaxRemovedCount) {
+    LOG(("CacheIndex::FrecencyArray::SortIfNeeded() - Sorting array "
+       "[unsortedElements=%u, unsortedLimit=%u, removedElements=%u, "
+       "maxRemovedCount=%u]", mUnsortedElements, unsortedLimit,
+       mRemovedElements, kMaxRemovedCount));
+
+    mRecs.Sort(FrecencyComparator());
+    mUnsortedElements = 0;
+    if (mRemovedElements) {
+#ifdef DEBUG
+      for (uint32_t i = Length(); i < mRecs.Length(); ++i) {
+        MOZ_ASSERT(!mRecs[i]);
+      }
+#endif
+      // Removed elements are at the end after sorting.
+      mRecs.RemoveElementsAt(Length(), mRemovedElements);
+      mRemovedElements = 0;
+    }
+  }
+}
+
+void
+CacheIndex::AddRecordToIterators(CacheIndexRecord *aRecord)
+{
+  sLock.AssertCurrentThreadOwns();
+
+  for (uint32_t i = 0; i < mIterators.Length(); ++i) {
+    // Add a new record only when iterator is supposed to be updated.
+    if (mIterators[i]->ShouldBeNewAdded()) {
+      mIterators[i]->AddRecord(aRecord);
+    }
+  }
+}
+
+void
+CacheIndex::RemoveRecordFromIterators(CacheIndexRecord *aRecord)
+{
+  sLock.AssertCurrentThreadOwns();
+
+  for (uint32_t i = 0; i < mIterators.Length(); ++i) {
+    // Remove the record from iterator always, it makes no sence to return
+    // non-existing entries. Also the pointer to the record is no longer valid
+    // once the entry is removed from index.
+    mIterators[i]->RemoveRecord(aRecord);
+  }
+}
+
+void
+CacheIndex::ReplaceRecordInIterators(CacheIndexRecord *aOldRecord,
+                                     CacheIndexRecord *aNewRecord)
+{
+  sLock.AssertCurrentThreadOwns();
+
+  for (uint32_t i = 0; i < mIterators.Length(); ++i) {
+    // We have to replace the record always since the pointer is no longer
+    // valid after this point. NOTE: Replacing the record doesn't mean that
+    // a new entry was added, it just means that the data in the entry was
+    // changed (e.g. a file size) and we had to track this change in
+    // mPendingUpdates since mIndex was read-only.
+    mIterators[i]->ReplaceRecord(aOldRecord, aNewRecord);
+  }
+}
+
+nsresult
+CacheIndex::Run()
+{
+  LOG(("CacheIndex::Run()"));
+
+  StaticMutexAutoLock lock(sLock);
+
+  if (!IsIndexUsable()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  if (mState == READY && mShuttingDown) {
+    return NS_OK;
+  }
+
+  mUpdateEventPending = false;
+
+  switch (mState) {
+    case BUILDING:
+      BuildIndex();
+      break;
+    case UPDATING:
+      UpdateIndex();
+      break;
+    default:
+      LOG(("CacheIndex::Run() - Update/Build was canceled"));
+  }
+
+  return NS_OK;
+}
+
+nsresult
+CacheIndex::OnFileOpenedInternal(FileOpenHelper *aOpener,
+                                 CacheFileHandle *aHandle, nsresult aResult)
+{
+  LOG(("CacheIndex::OnFileOpenedInternal() [opener=%p, handle=%p, "
+       "result=0x%08x]", aOpener, aHandle, aResult));
+
+  MOZ_ASSERT(CacheFileIOManager::IsOnIOThread());
+
+  nsresult rv;
+
+  sLock.AssertCurrentThreadOwns();
+
+  MOZ_RELEASE_ASSERT(IsIndexUsable());
+
+  if (mState == READY && mShuttingDown) {
+    return NS_OK;
+  }
+
+  switch (mState) {
+    case WRITING:
+      MOZ_ASSERT(aOpener == mIndexFileOpener);
+      mIndexFileOpener = nullptr;
+
+      if (NS_FAILED(aResult)) {
+        LOG(("CacheIndex::OnFileOpenedInternal() - Can't open index file for "
+             "writing [rv=0x%08x]", aResult));
+        FinishWrite(false);
+      } else {
+        mIndexHandle = aHandle;
+        WriteRecords();
+      }
+      break;
+    case READING:
+      if (aOpener == mIndexFileOpener) {
+        mIndexFileOpener = nullptr;
+
+        if (NS_SUCCEEDED(aResult)) {
+          if (aHandle->FileSize() == 0) {
+            FinishRead(false);
+            CacheFileIOManager::DoomFile(aHandle, nullptr);
+            break;
+          } else {
+            mIndexHandle = aHandle;
+          }
+        } else {
+          FinishRead(false);
+          break;
+        }
+      } else if (aOpener == mJournalFileOpener) {
+        mJournalFileOpener = nullptr;
+        mJournalHandle = aHandle;
+      } else if (aOpener == mTmpFileOpener) {
+        mTmpFileOpener = nullptr;
+        mTmpHandle = aHandle;
+      } else {
+        MOZ_ASSERT(false, "Unexpected state!");
+      }
+
+      if (mIndexFileOpener || mJournalFileOpener || mTmpFileOpener) {
+        // Some opener still didn't finish
+        break;
+      }
+
+      // We fail and cancel all other openers when we opening index file fails.
+      MOZ_ASSERT(mIndexHandle);
+
+      if (mTmpHandle) {
+        CacheFileIOManager::DoomFile(mTmpHandle, nullptr);
+        mTmpHandle = nullptr;
+
+        if (mJournalHandle) { // this shouldn't normally happen
+          LOG(("CacheIndex::OnFileOpenedInternal() - Unexpected state, all "
+               "files [%s, %s, %s] should never exist. Removing whole index.",
+               INDEX_NAME, JOURNAL_NAME, TEMP_INDEX_NAME));
+          FinishRead(false);
+          break;
+        }
+      }
+
+      if (mJournalHandle) {
+        // Rename journal to make sure we update index on next start in case
+        // firefox crashes
+        rv = CacheFileIOManager::RenameFile(
+          mJournalHandle, NS_LITERAL_CSTRING(TEMP_INDEX_NAME), this);
+        if (NS_FAILED(rv)) {
+          LOG(("CacheIndex::OnFileOpenedInternal() - CacheFileIOManager::"
+               "RenameFile() failed synchronously [rv=0x%08x]", rv));
+          FinishRead(false);
+          break;
+        }
+      } else {
+        StartReadingIndex();
+      }
+
+      break;
+    default:
+      MOZ_ASSERT(false, "Unexpected state!");
+  }
+
+  return NS_OK;
+}
+
+nsresult
+CacheIndex::OnFileOpened(CacheFileHandle *aHandle, nsresult aResult)
+{
+  MOZ_CRASH("CacheIndex::OnFileOpened should not be called!");
+  return NS_ERROR_UNEXPECTED;
+}
+
+nsresult
+CacheIndex::OnDataWritten(CacheFileHandle *aHandle, const char *aBuf,
+                          nsresult aResult)
+{
+  LOG(("CacheIndex::OnDataWritten() [handle=%p, result=0x%08x]", aHandle,
+       aResult));
+
+  MOZ_ASSERT(CacheFileIOManager::IsOnIOThread());
+
+  nsresult rv;
+
+  StaticMutexAutoLock lock(sLock);
+
+  MOZ_RELEASE_ASSERT(IsIndexUsable());
+  MOZ_RELEASE_ASSERT(mRWPending);
+  mRWPending = false;
+
+  if (mState == READY && mShuttingDown) {
+    return NS_OK;
+  }
+
+  switch (mState) {
+    case WRITING:
+      MOZ_ASSERT(mIndexHandle == aHandle);
+
+      if (NS_FAILED(aResult)) {
+        FinishWrite(false);
+      } else {
+        if (mSkipEntries == mProcessEntries) {
+          rv = CacheFileIOManager::RenameFile(mIndexHandle,
+                                              NS_LITERAL_CSTRING(INDEX_NAME),
+                                              this);
+          if (NS_FAILED(rv)) {
+            LOG(("CacheIndex::OnDataWritten() - CacheFileIOManager::"
+                 "RenameFile() failed synchronously [rv=0x%08x]", rv));
+            FinishWrite(false);
+          }
+        } else {
+          WriteRecords();
+        }
+      }
+      break;
+    default:
+      // Writing was canceled.
+      LOG(("CacheIndex::OnDataWritten() - ignoring notification since the "
+           "operation was previously canceled [state=%d]", mState));
+      ReleaseBuffer();
+  }
+
+  return NS_OK;
+}
+
+nsresult
+CacheIndex::OnDataRead(CacheFileHandle *aHandle, char *aBuf, nsresult aResult)
+{
+  LOG(("CacheIndex::OnDataRead() [handle=%p, result=0x%08x]", aHandle,
+       aResult));
+
+  MOZ_ASSERT(CacheFileIOManager::IsOnIOThread());
+
+  StaticMutexAutoLock lock(sLock);
+
+  MOZ_RELEASE_ASSERT(IsIndexUsable());
+  MOZ_RELEASE_ASSERT(mRWPending);
+  mRWPending = false;
+
+  switch (mState) {
+    case READING:
+      MOZ_ASSERT(mIndexHandle == aHandle || mJournalHandle == aHandle);
+
+      if (NS_FAILED(aResult)) {
+        FinishRead(false);
+      } else {
+        if (!mIndexOnDiskIsValid) {
+          ParseRecords();
+        } else {
+          ParseJournal();
+        }
+      }
+      break;
+    default:
+      // Reading was canceled.
+      LOG(("CacheIndex::OnDataRead() - ignoring notification since the "
+           "operation was previously canceled [state=%d]", mState));
+      ReleaseBuffer();
+  }
+
+  return NS_OK;
+}
+
+nsresult
+CacheIndex::OnFileDoomed(CacheFileHandle *aHandle, nsresult aResult)
+{
+  MOZ_CRASH("CacheIndex::OnFileDoomed should not be called!");
+  return NS_ERROR_UNEXPECTED;
+}
+
+nsresult
+CacheIndex::OnEOFSet(CacheFileHandle *aHandle, nsresult aResult)
+{
+  MOZ_CRASH("CacheIndex::OnEOFSet should not be called!");
+  return NS_ERROR_UNEXPECTED;
+}
+
+nsresult
+CacheIndex::OnFileRenamed(CacheFileHandle *aHandle, nsresult aResult)
+{
+  LOG(("CacheIndex::OnFileRenamed() [handle=%p, result=0x%08x]", aHandle,
+       aResult));
+
+  MOZ_ASSERT(CacheFileIOManager::IsOnIOThread());
+
+  StaticMutexAutoLock lock(sLock);
+
+  MOZ_RELEASE_ASSERT(IsIndexUsable());
+
+  if (mState == READY && mShuttingDown) {
+    return NS_OK;
+  }
+
+  switch (mState) {
+    case WRITING:
+      // This is a result of renaming the new index written to tmpfile to index
+      // file. This is the last step when writing the index and the whole
+      // writing process is successful iff renaming was successful.
+
+      if (mIndexHandle != aHandle) {
+        LOG(("CacheIndex::OnFileRenamed() - ignoring notification since it "
+             "belongs to previously canceled operation [state=%d]", mState));
+        break;
+      }
+
+      FinishWrite(NS_SUCCEEDED(aResult));
+      break;
+    case READING:
+      // This is a result of renaming journal file to tmpfile. It is renamed
+      // before we start reading index and journal file and it should normally
+      // succeed. If it fails give up reading of index.
+
+      if (mJournalHandle != aHandle) {
+        LOG(("CacheIndex::OnFileRenamed() - ignoring notification since it "
+             "belongs to previously canceled operation [state=%d]", mState));
+        break;
+      }
+
+      if (NS_FAILED(aResult)) {
+        FinishRead(false);
+      } else {
+        StartReadingIndex();
+      }
+      break;
+    default:
+      // Reading/writing was canceled.
+      LOG(("CacheIndex::OnFileRenamed() - ignoring notification since the "
+           "operation was previously canceled [state=%d]", mState));
+  }
+
+  return NS_OK;
+}
+
+// Memory reporting
+
+size_t
+CacheIndex::SizeOfExcludingThisInternal(mozilla::MallocSizeOf mallocSizeOf) const
+{
+  sLock.AssertCurrentThreadOwns();
+
+  size_t n = 0;
+  nsCOMPtr<nsISizeOf> sizeOf;
+
+  // mIndexHandle and mJournalHandle are reported via SizeOfHandlesRunnable
+  // in CacheFileIOManager::SizeOfExcludingThisInternal as part of special
+  // handles array.
+
+  sizeOf = do_QueryInterface(mCacheDirectory);
+  if (sizeOf) {
+    n += sizeOf->SizeOfIncludingThis(mallocSizeOf);
+  }
+
+  sizeOf = do_QueryInterface(mUpdateTimer);
+  if (sizeOf) {
+    n += sizeOf->SizeOfIncludingThis(mallocSizeOf);
+  }
+
+  n += mallocSizeOf(mRWBuf);
+  n += mallocSizeOf(mRWHash);
+
+  n += mIndex.SizeOfExcludingThis(mallocSizeOf);
+  n += mPendingUpdates.SizeOfExcludingThis(mallocSizeOf);
+  n += mTmpJournal.SizeOfExcludingThis(mallocSizeOf);
+
+  // mFrecencyArray items are reported by mIndex/mPendingUpdates
+  n += mFrecencyArray.mRecs.ShallowSizeOfExcludingThis(mallocSizeOf);
+  n += mDiskConsumptionObservers.ShallowSizeOfExcludingThis(mallocSizeOf);
+
+  return n;
+}
+
+// static
+size_t
+CacheIndex::SizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf)
+{
+  sLock.AssertCurrentThreadOwns();
+
+  if (!gInstance)
+    return 0;
+
+  return gInstance->SizeOfExcludingThisInternal(mallocSizeOf);
+}
+
+// static
+size_t
+CacheIndex::SizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf)
+{
+  StaticMutexAutoLock lock(sLock);
+
+  return mallocSizeOf(gInstance) + SizeOfExcludingThis(mallocSizeOf);
+}
+
+namespace {
+
+class HashComparator
+{
+public:
+  bool Equals(CacheIndexRecord* a, CacheIndexRecord* b) const {
+    return memcmp(&a->mHash, &b->mHash, sizeof(SHA1Sum::Hash)) == 0;
+  }
+  bool LessThan(CacheIndexRecord* a, CacheIndexRecord* b) const {
+    return memcmp(&a->mHash, &b->mHash, sizeof(SHA1Sum::Hash)) < 0;
+  }
+};
+
+void
+ReportHashSizeMatch(const SHA1Sum::Hash *aHash1, const SHA1Sum::Hash *aHash2)
+{
+  const uint32_t *h1 = reinterpret_cast<const uint32_t *>(aHash1);
+  const uint32_t *h2 = reinterpret_cast<const uint32_t *>(aHash2);
+
+  for (uint32_t i = 0; i < 5; ++i) {
+    if (h1[i] != h2[i]) {
+      uint32_t bitsDiff = h1[i] ^ h2[i];
+      bitsDiff = NetworkEndian::readUint32(&bitsDiff);
+
+      // count leading zeros in bitsDiff
+      static const uint8_t debruijn32[32] =
+        { 0, 31, 9, 30, 3, 8, 13, 29, 2, 5, 7, 21, 12, 24, 28, 19,
+          1, 10, 4, 14, 6, 22, 25, 20, 11, 15, 23, 26, 16, 27, 17, 18};
+
+      bitsDiff |= bitsDiff>>1;
+      bitsDiff |= bitsDiff>>2;
+      bitsDiff |= bitsDiff>>4;
+      bitsDiff |= bitsDiff>>8;
+      bitsDiff |= bitsDiff>>16;
+      bitsDiff++;
+
+      uint8_t hashSizeMatch = debruijn32[bitsDiff*0x076be629>>27] + (i<<5);
+      Telemetry::Accumulate(Telemetry::NETWORK_CACHE_HASH_STATS, hashSizeMatch);
+
+      return;
+    }
+  }
+
+  MOZ_ASSERT(false, "Found a collision in the index!");
+}
+
+} // namespace
+
+void
+CacheIndex::ReportHashStats()
+{
+  // We're gathering the hash stats only once, exclude too small caches.
+  if (CacheObserver::HashStatsReported() || mFrecencyArray.Length() < 15000) {
+    return;
+  }
+
+  nsTArray<CacheIndexRecord *> records;
+  for (auto iter = mFrecencyArray.Iter(); !iter.Done(); iter.Next()) {
+    records.AppendElement(iter.Get());
+  }
+
+  records.Sort(HashComparator());
+
+  for (uint32_t i = 1; i < records.Length(); i++) {
+    ReportHashSizeMatch(&records[i-1]->mHash, &records[i]->mHash);
+  }
+
+  CacheObserver::SetHashStatsReported();
+}
+
+// static
+void
+CacheIndex::OnAsyncEviction(bool aEvicting)
+{
+  RefPtr<CacheIndex> index = gInstance;
+  if (!index) {
+    return;
+  }
+
+  StaticMutexAutoLock lock(sLock);
+  index->mAsyncGetDiskConsumptionBlocked = aEvicting;
+  if (!aEvicting) {
+    index->NotifyAsyncGetDiskConsumptionCallbacks();
+  }
+}
+
+} // namespace net
+} // namespace mozilla