/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* vim: set ts=8 sts=2 et sw=2 tw=80: */ /* This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ #include "prio.h" #include "PLDHashTable.h" #include "nsXPCOMStrings.h" #include "mozilla/IOInterposer.h" #include "mozilla/MemoryReporting.h" #include "mozilla/scache/StartupCache.h" #include "nsAutoPtr.h" #include "nsClassHashtable.h" #include "nsComponentManagerUtils.h" #include "nsDirectoryServiceUtils.h" #include "nsIClassInfo.h" #include "nsIFile.h" #include "nsIObserver.h" #include "nsIObserverService.h" #include "nsIOutputStream.h" #include "nsIStartupCache.h" #include "nsIStorageStream.h" #include "nsIStreamBufferAccess.h" #include "nsIStringStream.h" #include "nsISupports.h" #include "nsITimer.h" #include "nsIZipWriter.h" #include "nsIZipReader.h" #include "nsWeakReference.h" #include "nsZipArchive.h" #include "mozilla/Omnijar.h" #include "prenv.h" #include "mozilla/Telemetry.h" #include "nsThreadUtils.h" #include "nsXULAppAPI.h" #include "nsIProtocolHandler.h" #ifdef IS_BIG_ENDIAN #define SC_ENDIAN "big" #else #define SC_ENDIAN "little" #endif #if PR_BYTES_PER_WORD == 4 #define SC_WORDSIZE "4" #else #define SC_WORDSIZE "8" #endif namespace mozilla { namespace scache { MOZ_DEFINE_MALLOC_SIZE_OF(StartupCacheMallocSizeOf) NS_IMETHODIMP StartupCache::CollectReports(nsIHandleReportCallback* aHandleReport, nsISupports* aData, bool aAnonymize) { #define REPORT(_path, _kind, _amount, _desc) \ do { \ nsresult rv = \ aHandleReport->Callback(EmptyCString(), \ NS_LITERAL_CSTRING(_path), \ _kind, UNITS_BYTES, _amount, \ NS_LITERAL_CSTRING(_desc), aData); \ NS_ENSURE_SUCCESS(rv, rv); \ } while (0) REPORT("explicit/startup-cache/mapping", KIND_NONHEAP, SizeOfMapping(), "Memory used to hold the mapping of the startup cache from file. " "This memory is likely to be swapped out shortly after start-up."); REPORT("explicit/startup-cache/data", KIND_HEAP, HeapSizeOfIncludingThis(StartupCacheMallocSizeOf), "Memory used by the startup cache for things other than the file " "mapping."); return NS_OK; } #define STARTUP_CACHE_NAME "startupCache." SC_WORDSIZE "." SC_ENDIAN StartupCache* StartupCache::GetSingleton() { if (!gStartupCache) { if (!XRE_IsParentProcess()) { return nullptr; } #ifdef MOZ_DISABLE_STARTUPCACHE return nullptr; #endif StartupCache::InitSingleton(); } return StartupCache::gStartupCache; } void StartupCache::DeleteSingleton() { StartupCache::gStartupCache = nullptr; } nsresult StartupCache::InitSingleton() { nsresult rv; StartupCache::gStartupCache = new StartupCache(); rv = StartupCache::gStartupCache->Init(); if (NS_FAILED(rv)) { StartupCache::gStartupCache = nullptr; } return rv; } StaticRefPtr StartupCache::gStartupCache; bool StartupCache::gShutdownInitiated; bool StartupCache::gIgnoreDiskCache; enum StartupCache::TelemetrifyAge StartupCache::gPostFlushAgeAction = StartupCache::IGNORE_AGE; NS_IMPL_ISUPPORTS(StartupCache, nsIMemoryReporter) StartupCache::StartupCache() : mArchive(nullptr), mStartupWriteInitiated(false), mWriteThread(nullptr) { } StartupCache::~StartupCache() { if (mTimer) { mTimer->Cancel(); } // Generally, the in-memory table should be empty here, // but an early shutdown means either mTimer didn't run // or the write thread is still running. WaitOnWriteThread(); // If we shutdown quickly timer wont have fired. Instead of writing // it on the main thread and block the shutdown we simply wont update // the startup cache. Always do this if the file doesn't exist since // we use it part of the package step. if (!mArchive) { WriteToDisk(); } UnregisterWeakMemoryReporter(this); } nsresult StartupCache::Init() { // workaround for bug 653936 nsCOMPtr jarInitializer(do_GetService(NS_NETWORK_PROTOCOL_CONTRACTID_PREFIX "jar")); nsresult rv; // This allows to override the startup cache filename // which is useful from xpcshell, when there is no ProfLDS directory to keep cache in. char *env = PR_GetEnv("MOZ_STARTUP_CACHE"); if (env) { rv = NS_NewLocalFile(NS_ConvertUTF8toUTF16(env), false, getter_AddRefs(mFile)); } else { nsCOMPtr file; rv = NS_GetSpecialDirectory("ProfLDS", getter_AddRefs(file)); if (NS_FAILED(rv)) { // return silently, this will fail in mochitests's xpcshell process. return rv; } nsCOMPtr profDir; NS_GetSpecialDirectory("ProfDS", getter_AddRefs(profDir)); if (profDir) { bool same; if (NS_SUCCEEDED(profDir->Equals(file, &same)) && !same) { // We no longer store the startup cache in the main profile // directory, so we should cleanup the old one. if (NS_SUCCEEDED( profDir->AppendNative(NS_LITERAL_CSTRING("startupCache")))) { profDir->Remove(true); } } } rv = file->AppendNative(NS_LITERAL_CSTRING("startupCache")); NS_ENSURE_SUCCESS(rv, rv); // Try to create the directory if it's not there yet rv = file->Create(nsIFile::DIRECTORY_TYPE, 0777); if (NS_FAILED(rv) && rv != NS_ERROR_FILE_ALREADY_EXISTS) return rv; rv = file->AppendNative(NS_LITERAL_CSTRING(STARTUP_CACHE_NAME)); NS_ENSURE_SUCCESS(rv, rv); mFile = do_QueryInterface(file); } NS_ENSURE_TRUE(mFile, NS_ERROR_UNEXPECTED); mObserverService = do_GetService("@mozilla.org/observer-service;1"); if (!mObserverService) { NS_WARNING("Could not get observerService."); return NS_ERROR_UNEXPECTED; } mListener = new StartupCacheListener(); rv = mObserverService->AddObserver(mListener, NS_XPCOM_SHUTDOWN_OBSERVER_ID, false); NS_ENSURE_SUCCESS(rv, rv); rv = mObserverService->AddObserver(mListener, "startupcache-invalidate", false); NS_ENSURE_SUCCESS(rv, rv); rv = LoadArchive(RECORD_AGE); // Sometimes we don't have a cache yet, that's ok. // If it's corrupted, just remove it and start over. if (gIgnoreDiskCache || (NS_FAILED(rv) && rv != NS_ERROR_FILE_NOT_FOUND)) { NS_WARNING("Failed to load startupcache file correctly, removing!"); InvalidateCache(); } RegisterWeakMemoryReporter(this); return NS_OK; } /** * LoadArchive can be called from the main thread or while reloading cache on write thread. */ nsresult StartupCache::LoadArchive(enum TelemetrifyAge flag) { if (gIgnoreDiskCache) return NS_ERROR_FAILURE; bool exists; mArchive = nullptr; nsresult rv = mFile->Exists(&exists); if (NS_FAILED(rv) || !exists) return NS_ERROR_FILE_NOT_FOUND; mArchive = new nsZipArchive(); rv = mArchive->OpenArchive(mFile); if (NS_FAILED(rv) || flag == IGNORE_AGE) return rv; nsCString comment; if (!mArchive->GetComment(comment)) { return rv; } const char *data; size_t len = NS_CStringGetData(comment, &data); PRTime creationStamp; // We might not have a comment if the startup cache file was created // before we started recording creation times in the comment. if (len == sizeof(creationStamp)) { memcpy(&creationStamp, data, len); PRTime current = PR_Now(); int64_t diff = current - creationStamp; // We can't use AccumulateTimeDelta here because we have no way of // reifying a TimeStamp from creationStamp. int64_t usec_per_hour = PR_USEC_PER_SEC * int64_t(3600); int64_t hour_diff = (diff + usec_per_hour - 1) / usec_per_hour; mozilla::Telemetry::Accumulate(Telemetry::STARTUP_CACHE_AGE_HOURS, hour_diff); } return rv; } namespace { nsresult GetBufferFromZipArchive(nsZipArchive *zip, bool doCRC, const char* id, UniquePtr* outbuf, uint32_t* length) { if (!zip) return NS_ERROR_NOT_AVAILABLE; nsZipItemPtr zipItem(zip, id, doCRC); if (!zipItem) return NS_ERROR_NOT_AVAILABLE; *outbuf = zipItem.Forget(); *length = zipItem.Length(); return NS_OK; } } /* anonymous namespace */ // NOTE: this will not find a new entry until it has been written to disk! // Consumer should take ownership of the resulting buffer. nsresult StartupCache::GetBuffer(const char* id, UniquePtr* outbuf, uint32_t* length) { PROFILER_LABEL_FUNC(js::ProfileEntry::Category::OTHER); NS_ASSERTION(NS_IsMainThread(), "Startup cache only available on main thread"); WaitOnWriteThread(); if (!mStartupWriteInitiated) { CacheEntry* entry; nsDependentCString idStr(id); mTable.Get(idStr, &entry); if (entry) { *outbuf = MakeUnique(entry->size); memcpy(outbuf->get(), entry->data.get(), entry->size); *length = entry->size; return NS_OK; } } nsresult rv = GetBufferFromZipArchive(mArchive, true, id, outbuf, length); if (NS_SUCCEEDED(rv)) return rv; RefPtr omnijar = mozilla::Omnijar::GetReader(mozilla::Omnijar::APP); // no need to checksum omnijarred entries rv = GetBufferFromZipArchive(omnijar, false, id, outbuf, length); if (NS_SUCCEEDED(rv)) return rv; omnijar = mozilla::Omnijar::GetReader(mozilla::Omnijar::GRE); // no need to checksum omnijarred entries return GetBufferFromZipArchive(omnijar, false, id, outbuf, length); } // Makes a copy of the buffer, client retains ownership of inbuf. nsresult StartupCache::PutBuffer(const char* id, const char* inbuf, uint32_t len) { NS_ASSERTION(NS_IsMainThread(), "Startup cache only available on main thread"); WaitOnWriteThread(); if (StartupCache::gShutdownInitiated) { return NS_ERROR_NOT_AVAILABLE; } auto data = MakeUnique(len); memcpy(data.get(), inbuf, len); nsCString idStr(id); // Cache it for now, we'll write all together later. CacheEntry* entry; if (mTable.Get(idStr)) { NS_ASSERTION(false, "Existing entry in StartupCache."); // Double-caching is undesirable but not an error. return NS_OK; } #ifdef DEBUG if (mArchive) { nsZipItem* zipItem = mArchive->GetItem(id); NS_ASSERTION(zipItem == nullptr, "Existing entry in disk StartupCache."); } #endif entry = new CacheEntry(Move(data), len); mTable.Put(idStr, entry); mPendingWrites.AppendElement(idStr); return ResetStartupWriteTimer(); } size_t StartupCache::SizeOfMapping() { return mArchive ? mArchive->SizeOfMapping() : 0; } size_t StartupCache::HeapSizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const { // This function could measure more members, but they haven't been found by // DMD to be significant. They can be added later if necessary. size_t n = aMallocSizeOf(this); n += mTable.ShallowSizeOfExcludingThis(aMallocSizeOf); for (auto iter = mTable.ConstIter(); !iter.Done(); iter.Next()) { n += iter.Data()->SizeOfIncludingThis(aMallocSizeOf); } n += mPendingWrites.ShallowSizeOfExcludingThis(aMallocSizeOf); return n; } struct CacheWriteHolder { nsCOMPtr writer; nsCOMPtr stream; PRTime time; }; static void CacheCloseHelper(const nsACString& key, const CacheEntry* data, const CacheWriteHolder* holder) { MOZ_ASSERT(data); // assert key was found in mTable. nsresult rv; nsIStringInputStream* stream = holder->stream; nsIZipWriter* writer = holder->writer; stream->ShareData(data->data.get(), data->size); #ifdef DEBUG bool hasEntry; rv = writer->HasEntry(key, &hasEntry); NS_ASSERTION(NS_SUCCEEDED(rv) && hasEntry == false, "Existing entry in disk StartupCache."); #endif rv = writer->AddEntryStream(key, holder->time, true, stream, false); if (NS_FAILED(rv)) { NS_WARNING("cache entry deleted but not written to disk."); } } /** * WriteToDisk writes the cache out to disk. Callers of WriteToDisk need to call WaitOnWriteThread * to make sure there isn't a write happening on another thread */ void StartupCache::WriteToDisk() { nsresult rv; mStartupWriteInitiated = true; if (mTable.Count() == 0) return; nsCOMPtr zipW = do_CreateInstance("@mozilla.org/zipwriter;1"); if (!zipW) return; rv = zipW->Open(mFile, PR_RDWR | PR_CREATE_FILE); if (NS_FAILED(rv)) { NS_WARNING("could not open zipfile for write"); return; } // If we didn't have an mArchive member, that means that we failed to // open the startup cache for reading. Therefore, we need to record // the time of creation in a zipfile comment; this will be useful for // Telemetry statistics. PRTime now = PR_Now(); if (!mArchive) { nsCString comment; comment.Assign((char *)&now, sizeof(now)); zipW->SetComment(comment); } nsCOMPtr stream = do_CreateInstance("@mozilla.org/io/string-input-stream;1", &rv); if (NS_FAILED(rv)) { NS_WARNING("Couldn't create string input stream."); return; } CacheWriteHolder holder; holder.stream = stream; holder.writer = zipW; holder.time = now; for (auto key = mPendingWrites.begin(); key != mPendingWrites.end(); key++) { CacheCloseHelper(*key, mTable.Get(*key), &holder); } mPendingWrites.Clear(); mTable.Clear(); // Close the archive so Windows doesn't choke. mArchive = nullptr; zipW->Close(); // We succesfully wrote the archive to disk; mark the disk file as trusted gIgnoreDiskCache = false; // Our reader's view of the archive is outdated now, reload it. LoadArchive(gPostFlushAgeAction); return; } void StartupCache::InvalidateCache() { WaitOnWriteThread(); mPendingWrites.Clear(); mTable.Clear(); mArchive = nullptr; nsresult rv = mFile->Remove(false); if (NS_FAILED(rv) && rv != NS_ERROR_FILE_TARGET_DOES_NOT_EXIST && rv != NS_ERROR_FILE_NOT_FOUND) { gIgnoreDiskCache = true; mozilla::Telemetry::Accumulate(Telemetry::STARTUP_CACHE_INVALID, true); return; } gIgnoreDiskCache = false; LoadArchive(gPostFlushAgeAction); } void StartupCache::IgnoreDiskCache() { gIgnoreDiskCache = true; if (gStartupCache) gStartupCache->InvalidateCache(); } /* * WaitOnWriteThread() is called from a main thread to wait for the worker * thread to finish. However since the same code is used in the worker thread and * main thread, the worker thread can also call WaitOnWriteThread() which is a no-op. */ void StartupCache::WaitOnWriteThread() { NS_ASSERTION(NS_IsMainThread(), "Startup cache should only wait for io thread on main thread"); if (!mWriteThread || mWriteThread == PR_GetCurrentThread()) return; PR_JoinThread(mWriteThread); mWriteThread = nullptr; } void StartupCache::ThreadedWrite(void *aClosure) { PR_SetCurrentThreadName("StartupCache"); mozilla::IOInterposer::RegisterCurrentThread(); /* * It is safe to use the pointer passed in aClosure to reference the * StartupCache object because the thread's lifetime is tightly coupled to * the lifetime of the StartupCache object; this thread is joined in the * StartupCache destructor, guaranteeing that this function runs if and only * if the StartupCache object is valid. */ StartupCache* startupCacheObj = static_cast(aClosure); startupCacheObj->WriteToDisk(); mozilla::IOInterposer::UnregisterCurrentThread(); } /* * The write-thread is spawned on a timeout(which is reset with every write). This * can avoid a slow shutdown. After writing out the cache, the zipreader is * reloaded on the worker thread. */ void StartupCache::WriteTimeout(nsITimer *aTimer, void *aClosure) { /* * It is safe to use the pointer passed in aClosure to reference the * StartupCache object because the timer's lifetime is tightly coupled to * the lifetime of the StartupCache object; this timer is canceled in the * StartupCache destructor, guaranteeing that this function runs if and only * if the StartupCache object is valid. */ StartupCache* startupCacheObj = static_cast(aClosure); startupCacheObj->mWriteThread = PR_CreateThread(PR_USER_THREAD, StartupCache::ThreadedWrite, startupCacheObj, PR_PRIORITY_NORMAL, PR_GLOBAL_THREAD, PR_JOINABLE_THREAD, 0); } // We don't want to refcount StartupCache, so we'll just // hold a ref to this and pass it to observerService instead. NS_IMPL_ISUPPORTS(StartupCacheListener, nsIObserver) nsresult StartupCacheListener::Observe(nsISupports *subject, const char* topic, const char16_t* data) { StartupCache* sc = StartupCache::GetSingleton(); if (!sc) return NS_OK; if (strcmp(topic, NS_XPCOM_SHUTDOWN_OBSERVER_ID) == 0) { // Do not leave the thread running past xpcom shutdown sc->WaitOnWriteThread(); StartupCache::gShutdownInitiated = true; } else if (strcmp(topic, "startupcache-invalidate") == 0) { sc->InvalidateCache(); } return NS_OK; } nsresult StartupCache::GetDebugObjectOutputStream(nsIObjectOutputStream* aStream, nsIObjectOutputStream** aOutStream) { NS_ENSURE_ARG_POINTER(aStream); #ifdef DEBUG StartupCacheDebugOutputStream* stream = new StartupCacheDebugOutputStream(aStream, &mWriteObjectMap); NS_ADDREF(*aOutStream = stream); #else NS_ADDREF(*aOutStream = aStream); #endif return NS_OK; } nsresult StartupCache::ResetStartupWriteTimer() { mStartupWriteInitiated = false; nsresult rv; if (!mTimer) mTimer = do_CreateInstance("@mozilla.org/timer;1", &rv); else rv = mTimer->Cancel(); NS_ENSURE_SUCCESS(rv, rv); // Wait for 10 seconds, then write out the cache. mTimer->InitWithFuncCallback(StartupCache::WriteTimeout, this, 60000, nsITimer::TYPE_ONE_SHOT); return NS_OK; } nsresult StartupCache::RecordAgesAlways() { gPostFlushAgeAction = RECORD_AGE; return NS_OK; } // StartupCacheDebugOutputStream implementation #ifdef DEBUG NS_IMPL_ISUPPORTS(StartupCacheDebugOutputStream, nsIObjectOutputStream, nsIBinaryOutputStream, nsIOutputStream) bool StartupCacheDebugOutputStream::CheckReferences(nsISupports* aObject) { nsresult rv; nsCOMPtr classInfo = do_QueryInterface(aObject); if (!classInfo) { NS_ERROR("aObject must implement nsIClassInfo"); return false; } uint32_t flags; rv = classInfo->GetFlags(&flags); NS_ENSURE_SUCCESS(rv, false); if (flags & nsIClassInfo::SINGLETON) return true; nsISupportsHashKey* key = mObjectMap->GetEntry(aObject); if (key) { NS_ERROR("non-singleton aObject is referenced multiple times in this" "serialization, we don't support that."); return false; } mObjectMap->PutEntry(aObject); return true; } // nsIObjectOutputStream implementation nsresult StartupCacheDebugOutputStream::WriteObject(nsISupports* aObject, bool aIsStrongRef) { nsCOMPtr rootObject(do_QueryInterface(aObject)); NS_ASSERTION(rootObject.get() == aObject, "bad call to WriteObject -- call WriteCompoundObject!"); bool check = CheckReferences(aObject); NS_ENSURE_TRUE(check, NS_ERROR_FAILURE); return mBinaryStream->WriteObject(aObject, aIsStrongRef); } nsresult StartupCacheDebugOutputStream::WriteSingleRefObject(nsISupports* aObject) { nsCOMPtr rootObject(do_QueryInterface(aObject)); NS_ASSERTION(rootObject.get() == aObject, "bad call to WriteSingleRefObject -- call WriteCompoundObject!"); bool check = CheckReferences(aObject); NS_ENSURE_TRUE(check, NS_ERROR_FAILURE); return mBinaryStream->WriteSingleRefObject(aObject); } nsresult StartupCacheDebugOutputStream::WriteCompoundObject(nsISupports* aObject, const nsIID& aIID, bool aIsStrongRef) { nsCOMPtr rootObject(do_QueryInterface(aObject)); nsCOMPtr roundtrip; rootObject->QueryInterface(aIID, getter_AddRefs(roundtrip)); NS_ASSERTION(roundtrip.get() == aObject, "bad aggregation or multiple inheritance detected by call to " "WriteCompoundObject!"); bool check = CheckReferences(aObject); NS_ENSURE_TRUE(check, NS_ERROR_FAILURE); return mBinaryStream->WriteCompoundObject(aObject, aIID, aIsStrongRef); } nsresult StartupCacheDebugOutputStream::WriteID(nsID const& aID) { return mBinaryStream->WriteID(aID); } char* StartupCacheDebugOutputStream::GetBuffer(uint32_t aLength, uint32_t aAlignMask) { return mBinaryStream->GetBuffer(aLength, aAlignMask); } void StartupCacheDebugOutputStream::PutBuffer(char* aBuffer, uint32_t aLength) { mBinaryStream->PutBuffer(aBuffer, aLength); } #endif //DEBUG StartupCacheWrapper* StartupCacheWrapper::gStartupCacheWrapper = nullptr; NS_IMPL_ISUPPORTS(StartupCacheWrapper, nsIStartupCache) StartupCacheWrapper* StartupCacheWrapper::GetSingleton() { if (!gStartupCacheWrapper) gStartupCacheWrapper = new StartupCacheWrapper(); NS_ADDREF(gStartupCacheWrapper); return gStartupCacheWrapper; } nsresult StartupCacheWrapper::GetBuffer(const char* id, char** outbuf, uint32_t* length) { StartupCache* sc = StartupCache::GetSingleton(); if (!sc) { return NS_ERROR_NOT_INITIALIZED; } UniquePtr buf; nsresult rv = sc->GetBuffer(id, &buf, length); *outbuf = buf.release(); return rv; } nsresult StartupCacheWrapper::PutBuffer(const char* id, const char* inbuf, uint32_t length) { StartupCache* sc = StartupCache::GetSingleton(); if (!sc) { return NS_ERROR_NOT_INITIALIZED; } return sc->PutBuffer(id, inbuf, length); } nsresult StartupCacheWrapper::InvalidateCache() { StartupCache* sc = StartupCache::GetSingleton(); if (!sc) { return NS_ERROR_NOT_INITIALIZED; } sc->InvalidateCache(); return NS_OK; } nsresult StartupCacheWrapper::IgnoreDiskCache() { StartupCache::IgnoreDiskCache(); return NS_OK; } nsresult StartupCacheWrapper::GetDebugObjectOutputStream(nsIObjectOutputStream* stream, nsIObjectOutputStream** outStream) { StartupCache* sc = StartupCache::GetSingleton(); if (!sc) { return NS_ERROR_NOT_INITIALIZED; } return sc->GetDebugObjectOutputStream(stream, outStream); } nsresult StartupCacheWrapper::StartupWriteComplete(bool *complete) { StartupCache* sc = StartupCache::GetSingleton(); if (!sc) { return NS_ERROR_NOT_INITIALIZED; } sc->WaitOnWriteThread(); *complete = sc->mStartupWriteInitiated && sc->mTable.Count() == 0; return NS_OK; } nsresult StartupCacheWrapper::ResetStartupWriteTimer() { StartupCache* sc = StartupCache::GetSingleton(); return sc ? sc->ResetStartupWriteTimer() : NS_ERROR_NOT_INITIALIZED; } nsresult StartupCacheWrapper::GetObserver(nsIObserver** obv) { StartupCache* sc = StartupCache::GetSingleton(); if (!sc) { return NS_ERROR_NOT_INITIALIZED; } NS_ADDREF(*obv = sc->mListener); return NS_OK; } nsresult StartupCacheWrapper::RecordAgesAlways() { StartupCache *sc = StartupCache::GetSingleton(); return sc ? sc->RecordAgesAlways() : NS_ERROR_NOT_INITIALIZED; } } // namespace scache } // namespace mozilla