Adding upstream version 86.0.1.upstream/86.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1509 insertions, 0 deletions

diff --git a/dom/serviceworkers/ServiceWorkerScriptCache.cpp b/dom/serviceworkers/ServiceWorkerScriptCache.cpp
new file mode 100644
index 0000000000..060d26da0c
--- /dev/null
+++ b/dom/serviceworkers/ServiceWorkerScriptCache.cpp
@@ -0,0 +1,1509 @@
+/* -*- 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 "ServiceWorkerScriptCache.h"
+
+#include "js/Array.h"  // JS::GetArrayLength
+#include "mozilla/Unused.h"
+#include "mozilla/dom/CacheBinding.h"
+#include "mozilla/dom/cache/CacheStorage.h"
+#include "mozilla/dom/cache/Cache.h"
+#include "mozilla/dom/Promise.h"
+#include "mozilla/dom/PromiseWorkerProxy.h"
+#include "mozilla/dom/ScriptLoader.h"
+#include "mozilla/dom/WorkerCommon.h"
+#include "mozilla/ipc/BackgroundUtils.h"
+#include "mozilla/ipc/PBackgroundSharedTypes.h"
+#include "mozilla/net/CookieJarSettings.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/StaticPrefs_extensions.h"
+#include "nsICacheInfoChannel.h"
+#include "nsIHttpChannel.h"
+#include "nsIStreamLoader.h"
+#include "nsIThreadRetargetableRequest.h"
+#include "nsIUUIDGenerator.h"
+#include "nsIXPConnect.h"
+
+#include "nsIInputStreamPump.h"
+#include "nsIPrincipal.h"
+#include "nsIScriptSecurityManager.h"
+#include "nsContentUtils.h"
+#include "nsNetUtil.h"
+#include "ServiceWorkerManager.h"
+#include "nsStringStream.h"
+
+using mozilla::dom::cache::Cache;
+using mozilla::dom::cache::CacheStorage;
+using mozilla::ipc::PrincipalInfo;
+
+namespace mozilla {
+namespace dom {
+
+namespace serviceWorkerScriptCache {
+
+namespace {
+
+already_AddRefed<CacheStorage> CreateCacheStorage(JSContext* aCx,
+                                                  nsIPrincipal* aPrincipal,
+                                                  ErrorResult& aRv) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aPrincipal);
+
+  nsIXPConnect* xpc = nsContentUtils::XPConnect();
+  MOZ_ASSERT(xpc, "This should never be null!");
+  JS::Rooted<JSObject*> sandbox(aCx);
+  aRv = xpc->CreateSandbox(aCx, aPrincipal, sandbox.address());
+  if (NS_WARN_IF(aRv.Failed())) {
+    return nullptr;
+  }
+
+  // This is called when the JSContext is not in a realm, so CreateSandbox
+  // returned an unwrapped global.
+  MOZ_ASSERT(JS_IsGlobalObject(sandbox));
+
+  nsCOMPtr<nsIGlobalObject> sandboxGlobalObject = xpc::NativeGlobal(sandbox);
+  if (!sandboxGlobalObject) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return nullptr;
+  }
+
+  // We assume private browsing is not enabled here.  The ScriptLoader
+  // explicitly fails for private browsing so there should never be
+  // a service worker running in private browsing mode.  Therefore if
+  // we are purging scripts or running a comparison algorithm we cannot
+  // be in private browsing.
+  //
+  // Also, bypass the CacheStorage trusted origin checks.  The ServiceWorker
+  // has validated the origin prior to this point.  All the information
+  // to revalidate is not available now.
+  return CacheStorage::CreateOnMainThread(cache::CHROME_ONLY_NAMESPACE,
+                                          sandboxGlobalObject, aPrincipal,
+                                          true /* force trusted origin */, aRv);
+}
+
+class CompareManager;
+class CompareCache;
+
+// This class downloads a URL from the network, compare the downloaded script
+// with an existing cache if provided, and report to CompareManager via calling
+// ComparisonFinished().
+class CompareNetwork final : public nsIStreamLoaderObserver,
+                             public nsIRequestObserver {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSISTREAMLOADEROBSERVER
+  NS_DECL_NSIREQUESTOBSERVER
+
+  CompareNetwork(CompareManager* aManager,
+                 ServiceWorkerRegistrationInfo* aRegistration,
+                 bool aIsMainScript)
+      : mManager(aManager),
+        mRegistration(aRegistration),
+        mInternalHeaders(new InternalHeaders()),
+        mLoadFlags(nsIChannel::LOAD_BYPASS_SERVICE_WORKER),
+        mState(WaitingForInitialization),
+        mNetworkResult(NS_OK),
+        mCacheResult(NS_OK),
+        mIsMainScript(aIsMainScript),
+        mIsFromCache(false) {
+    MOZ_ASSERT(aManager);
+    MOZ_ASSERT(NS_IsMainThread());
+  }
+
+  nsresult Initialize(nsIPrincipal* aPrincipal, const nsAString& aURL,
+                      Cache* const aCache);
+
+  void Abort();
+
+  void NetworkFinish(nsresult aRv);
+
+  void CacheFinish(nsresult aRv);
+
+  const nsString& URL() const {
+    MOZ_ASSERT(NS_IsMainThread());
+    return mURL;
+  }
+
+  const nsString& Buffer() const {
+    MOZ_ASSERT(NS_IsMainThread());
+    return mBuffer;
+  }
+
+  const ChannelInfo& GetChannelInfo() const { return mChannelInfo; }
+
+  already_AddRefed<InternalHeaders> GetInternalHeaders() const {
+    RefPtr<InternalHeaders> internalHeaders = mInternalHeaders;
+    return internalHeaders.forget();
+  }
+
+  UniquePtr<PrincipalInfo> TakePrincipalInfo() {
+    return std::move(mPrincipalInfo);
+  }
+
+  bool Succeeded() const { return NS_SUCCEEDED(mNetworkResult); }
+
+  const nsTArray<nsCString>& URLList() const { return mURLList; }
+
+ private:
+  ~CompareNetwork() {
+    MOZ_ASSERT(NS_IsMainThread());
+    MOZ_ASSERT(!mCC);
+  }
+
+  void Finish();
+
+  nsresult SetPrincipalInfo(nsIChannel* aChannel);
+
+  RefPtr<CompareManager> mManager;
+  RefPtr<CompareCache> mCC;
+  RefPtr<ServiceWorkerRegistrationInfo> mRegistration;
+
+  nsCOMPtr<nsIChannel> mChannel;
+  nsString mBuffer;
+  nsString mURL;
+  ChannelInfo mChannelInfo;
+  RefPtr<InternalHeaders> mInternalHeaders;
+  UniquePtr<PrincipalInfo> mPrincipalInfo;
+  nsTArray<nsCString> mURLList;
+
+  nsCString mMaxScope;
+  nsLoadFlags mLoadFlags;
+
+  enum {
+    WaitingForInitialization,
+    WaitingForBothFinished,
+    WaitingForNetworkFinished,
+    WaitingForCacheFinished,
+    Finished
+  } mState;
+
+  nsresult mNetworkResult;
+  nsresult mCacheResult;
+
+  const bool mIsMainScript;
+  bool mIsFromCache;
+};
+
+NS_IMPL_ISUPPORTS(CompareNetwork, nsIStreamLoaderObserver, nsIRequestObserver)
+
+// This class gets a cached Response from the CacheStorage and then it calls
+// CacheFinish() in the CompareNetwork.
+class CompareCache final : public PromiseNativeHandler,
+                           public nsIStreamLoaderObserver {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSISTREAMLOADEROBSERVER
+
+  explicit CompareCache(CompareNetwork* aCN)
+      : mCN(aCN), mState(WaitingForInitialization), mInCache(false) {
+    MOZ_ASSERT(aCN);
+    MOZ_ASSERT(NS_IsMainThread());
+  }
+
+  nsresult Initialize(Cache* const aCache, const nsAString& aURL);
+
+  void Finish(nsresult aStatus, bool aInCache);
+
+  void Abort();
+
+  virtual void ResolvedCallback(JSContext* aCx,
+                                JS::Handle<JS::Value> aValue) override;
+
+  virtual void RejectedCallback(JSContext* aCx,
+                                JS::Handle<JS::Value> aValue) override;
+
+  const nsString& Buffer() const {
+    MOZ_ASSERT(NS_IsMainThread());
+    return mBuffer;
+  }
+
+  bool InCache() { return mInCache; }
+
+ private:
+  ~CompareCache() { MOZ_ASSERT(NS_IsMainThread()); }
+
+  void ManageValueResult(JSContext* aCx, JS::Handle<JS::Value> aValue);
+
+  RefPtr<CompareNetwork> mCN;
+  nsCOMPtr<nsIInputStreamPump> mPump;
+
+  nsString mURL;
+  nsString mBuffer;
+
+  enum {
+    WaitingForInitialization,
+    WaitingForScript,
+    Finished,
+  } mState;
+
+  bool mInCache;
+};
+
+NS_IMPL_ISUPPORTS(CompareCache, nsIStreamLoaderObserver)
+
+class CompareManager final : public PromiseNativeHandler {
+ public:
+  NS_DECL_ISUPPORTS
+
+  explicit CompareManager(ServiceWorkerRegistrationInfo* aRegistration,
+                          CompareCallback* aCallback)
+      : mRegistration(aRegistration),
+        mCallback(aCallback),
+        mLoadFlags(nsIChannel::LOAD_BYPASS_SERVICE_WORKER),
+        mState(WaitingForInitialization),
+        mPendingCount(0),
+        mOnFailure(OnFailure::DoNothing),
+        mAreScriptsEqual(true) {
+    MOZ_ASSERT(NS_IsMainThread());
+    MOZ_ASSERT(aRegistration);
+  }
+
+  nsresult Initialize(nsIPrincipal* aPrincipal, const nsAString& aURL,
+                      const nsAString& aCacheName);
+
+  void ResolvedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue) override;
+
+  void RejectedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue) override;
+
+  CacheStorage* CacheStorage_() {
+    MOZ_ASSERT(NS_IsMainThread());
+    MOZ_ASSERT(mCacheStorage);
+    return mCacheStorage;
+  }
+
+  void ComparisonFinished(nsresult aStatus, bool aIsMainScript, bool aIsEqual,
+                          const nsACString& aMaxScope, nsLoadFlags aLoadFlags) {
+    MOZ_ASSERT(NS_IsMainThread());
+    if (mState == Finished) {
+      return;
+    }
+
+    MOZ_DIAGNOSTIC_ASSERT(mState == WaitingForScriptOrComparisonResult);
+
+    if (NS_WARN_IF(NS_FAILED(aStatus))) {
+      Fail(aStatus);
+      return;
+    }
+
+    mAreScriptsEqual = mAreScriptsEqual && aIsEqual;
+
+    if (aIsMainScript) {
+      mMaxScope = aMaxScope;
+      mLoadFlags = aLoadFlags;
+    }
+
+    // Check whether all CompareNetworks finished their jobs.
+    MOZ_DIAGNOSTIC_ASSERT(mPendingCount > 0);
+    if (--mPendingCount) {
+      return;
+    }
+
+    if (mAreScriptsEqual) {
+      MOZ_ASSERT(mCallback);
+      mCallback->ComparisonResult(aStatus, true /* aSameScripts */, mOnFailure,
+                                  u""_ns, mMaxScope, mLoadFlags);
+      Cleanup();
+      return;
+    }
+
+    // Write to Cache so ScriptLoader reads succeed.
+    WriteNetworkBufferToNewCache();
+  }
+
+ private:
+  ~CompareManager() {
+    MOZ_ASSERT(NS_IsMainThread());
+    MOZ_ASSERT(mCNList.Length() == 0);
+  }
+
+  void Fail(nsresult aStatus);
+
+  void Cleanup();
+
+  nsresult FetchScript(const nsAString& aURL, bool aIsMainScript,
+                       Cache* const aCache = nullptr) {
+    MOZ_ASSERT(NS_IsMainThread());
+
+    MOZ_DIAGNOSTIC_ASSERT(mState == WaitingForInitialization ||
+                          mState == WaitingForScriptOrComparisonResult);
+
+    RefPtr<CompareNetwork> cn =
+        new CompareNetwork(this, mRegistration, aIsMainScript);
+    mCNList.AppendElement(cn);
+    mPendingCount += 1;
+
+    nsresult rv = cn->Initialize(mPrincipal, aURL, aCache);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+
+    return NS_OK;
+  }
+
+  void ManageOldCache(JSContext* aCx, JS::Handle<JS::Value> aValue) {
+    MOZ_DIAGNOSTIC_ASSERT(mState == WaitingForExistingOpen);
+
+    // RAII Cleanup when fails.
+    nsresult rv = NS_ERROR_FAILURE;
+    auto guard = MakeScopeExit([&] { Fail(rv); });
+
+    if (NS_WARN_IF(!aValue.isObject())) {
+      return;
+    }
+
+    MOZ_ASSERT(!mOldCache);
+    JS::Rooted<JSObject*> obj(aCx, &aValue.toObject());
+    if (NS_WARN_IF(!obj) ||
+        NS_WARN_IF(NS_FAILED(UNWRAP_OBJECT(Cache, obj, mOldCache)))) {
+      return;
+    }
+
+    Optional<RequestOrUSVString> request;
+    CacheQueryOptions options;
+    ErrorResult error;
+    RefPtr<Promise> promise = mOldCache->Keys(aCx, request, options, error);
+    if (NS_WARN_IF(error.Failed())) {
+      // No exception here because there are no ReadableStreams involved here.
+      MOZ_ASSERT(!error.IsJSException());
+      rv = error.StealNSResult();
+      return;
+    }
+
+    mState = WaitingForExistingKeys;
+    promise->AppendNativeHandler(this);
+    guard.release();
+  }
+
+  void ManageOldKeys(JSContext* aCx, JS::Handle<JS::Value> aValue) {
+    MOZ_DIAGNOSTIC_ASSERT(mState == WaitingForExistingKeys);
+
+    // RAII Cleanup when fails.
+    nsresult rv = NS_ERROR_FAILURE;
+    auto guard = MakeScopeExit([&] { Fail(rv); });
+
+    if (NS_WARN_IF(!aValue.isObject())) {
+      return;
+    }
+
+    JS::Rooted<JSObject*> obj(aCx, &aValue.toObject());
+    if (NS_WARN_IF(!obj)) {
+      return;
+    }
+
+    uint32_t len = 0;
+    if (!JS::GetArrayLength(aCx, obj, &len)) {
+      return;
+    }
+
+    // Fetch and compare the source scripts.
+    MOZ_ASSERT(mPendingCount == 0);
+
+    mState = WaitingForScriptOrComparisonResult;
+
+    bool hasMainScript = false;
+    AutoTArray<nsString, 8> urlList;
+
+    // Extract the list of URLs in the old cache.
+    for (uint32_t i = 0; i < len; ++i) {
+      JS::Rooted<JS::Value> val(aCx);
+      if (NS_WARN_IF(!JS_GetElement(aCx, obj, i, &val)) ||
+          NS_WARN_IF(!val.isObject())) {
+        return;
+      }
+
+      Request* request;
+      JS::Rooted<JSObject*> requestObj(aCx, &val.toObject());
+      if (NS_WARN_IF(NS_FAILED(UNWRAP_OBJECT(Request, &requestObj, request)))) {
+        return;
+      };
+
+      nsString url;
+      request->GetUrl(url);
+
+      if (!hasMainScript && url == mURL) {
+        hasMainScript = true;
+      }
+
+      urlList.AppendElement(url);
+    }
+
+    // If the main script is missing, then something has gone wrong.  We
+    // will try to continue with the update process to trigger a new
+    // installation.  If that fails, however, then uninstall the registration
+    // because it is broken in a way that cannot be fixed.
+    if (!hasMainScript) {
+      mOnFailure = OnFailure::Uninstall;
+    }
+
+    // Always make sure to fetch the main script.  If the old cache has
+    // no entries or the main script entry is missing, then the loop below
+    // may not trigger it.  This should not really happen, but we handle it
+    // gracefully if it does occur.  Its possible the bad cache state is due
+    // to a crash or shutdown during an update, etc.
+    rv = FetchScript(mURL, true /* aIsMainScript */, mOldCache);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return;
+    }
+
+    for (const auto& url : urlList) {
+      // We explicitly start the fetch for the main script above.
+      if (mURL == url) {
+        continue;
+      }
+
+      rv = FetchScript(url, false /* aIsMainScript */, mOldCache);
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return;
+      }
+    }
+
+    guard.release();
+  }
+
+  void ManageNewCache(JSContext* aCx, JS::Handle<JS::Value> aValue) {
+    MOZ_DIAGNOSTIC_ASSERT(mState == WaitingForOpen);
+
+    // RAII Cleanup when fails.
+    nsresult rv = NS_ERROR_FAILURE;
+    auto guard = MakeScopeExit([&] { Fail(rv); });
+
+    if (NS_WARN_IF(!aValue.isObject())) {
+      return;
+    }
+
+    JS::Rooted<JSObject*> obj(aCx, &aValue.toObject());
+    if (NS_WARN_IF(!obj)) {
+      return;
+    }
+
+    Cache* cache = nullptr;
+    rv = UNWRAP_OBJECT(Cache, &obj, cache);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return;
+    }
+
+    // Just to be safe.
+    RefPtr<Cache> kungfuDeathGrip = cache;
+
+    MOZ_ASSERT(mPendingCount == 0);
+    for (uint32_t i = 0; i < mCNList.Length(); ++i) {
+      // We bail out immediately when something goes wrong.
+      rv = WriteToCache(aCx, cache, mCNList[i]);
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return;
+      }
+    }
+
+    mState = WaitingForPut;
+    guard.release();
+  }
+
+  void WriteNetworkBufferToNewCache() {
+    MOZ_ASSERT(NS_IsMainThread());
+    MOZ_ASSERT(mCNList.Length() != 0);
+    MOZ_ASSERT(mCacheStorage);
+    MOZ_ASSERT(mNewCacheName.IsEmpty());
+
+    ErrorResult result;
+    result = serviceWorkerScriptCache::GenerateCacheName(mNewCacheName);
+    if (NS_WARN_IF(result.Failed())) {
+      MOZ_ASSERT(!result.IsErrorWithMessage());
+      Fail(result.StealNSResult());
+      return;
+    }
+
+    RefPtr<Promise> cacheOpenPromise =
+        mCacheStorage->Open(mNewCacheName, result);
+    if (NS_WARN_IF(result.Failed())) {
+      MOZ_ASSERT(!result.IsErrorWithMessage());
+      Fail(result.StealNSResult());
+      return;
+    }
+
+    mState = WaitingForOpen;
+    cacheOpenPromise->AppendNativeHandler(this);
+  }
+
+  nsresult WriteToCache(JSContext* aCx, Cache* aCache, CompareNetwork* aCN) {
+    MOZ_ASSERT(NS_IsMainThread());
+    MOZ_ASSERT(aCache);
+    MOZ_ASSERT(aCN);
+    MOZ_DIAGNOSTIC_ASSERT(mState == WaitingForOpen);
+
+    // We don't have to save any information from a failed CompareNetwork.
+    if (!aCN->Succeeded()) {
+      return NS_OK;
+    }
+
+    nsCOMPtr<nsIInputStream> body;
+    nsresult rv = NS_NewCStringInputStream(
+        getter_AddRefs(body), NS_ConvertUTF16toUTF8(aCN->Buffer()));
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+
+    RefPtr<InternalResponse> ir = new InternalResponse(200, "OK"_ns);
+    ir->SetBody(body, aCN->Buffer().Length());
+    ir->SetURLList(aCN->URLList());
+
+    ir->InitChannelInfo(aCN->GetChannelInfo());
+    UniquePtr<PrincipalInfo> principalInfo = aCN->TakePrincipalInfo();
+    if (principalInfo) {
+      ir->SetPrincipalInfo(std::move(principalInfo));
+    }
+
+    RefPtr<InternalHeaders> internalHeaders = aCN->GetInternalHeaders();
+    ir->Headers()->Fill(*(internalHeaders.get()), IgnoreErrors());
+
+    RefPtr<Response> response =
+        new Response(aCache->GetGlobalObject(), ir, nullptr);
+
+    RequestOrUSVString request;
+    request.SetAsUSVString().ShareOrDependUpon(aCN->URL());
+
+    // For now we have to wait until the Put Promise is fulfilled before we can
+    // continue since Cache does not yet support starting a read that is being
+    // written to.
+    ErrorResult result;
+    RefPtr<Promise> cachePromise = aCache->Put(aCx, request, *response, result);
+    result.WouldReportJSException();
+    if (NS_WARN_IF(result.Failed())) {
+      // No exception here because there are no ReadableStreams involved here.
+      MOZ_ASSERT(!result.IsJSException());
+      MOZ_ASSERT(!result.IsErrorWithMessage());
+      return result.StealNSResult();
+    }
+
+    mPendingCount += 1;
+    cachePromise->AppendNativeHandler(this);
+    return NS_OK;
+  }
+
+  RefPtr<ServiceWorkerRegistrationInfo> mRegistration;
+  RefPtr<CompareCallback> mCallback;
+  RefPtr<CacheStorage> mCacheStorage;
+
+  nsTArray<RefPtr<CompareNetwork>> mCNList;
+
+  nsString mURL;
+  RefPtr<nsIPrincipal> mPrincipal;
+
+  // Used for the old cache where saves the old source scripts.
+  RefPtr<Cache> mOldCache;
+
+  // Only used if the network script has changed and needs to be cached.
+  nsString mNewCacheName;
+
+  nsCString mMaxScope;
+  nsLoadFlags mLoadFlags;
+
+  enum {
+    WaitingForInitialization,
+    WaitingForExistingOpen,
+    WaitingForExistingKeys,
+    WaitingForScriptOrComparisonResult,
+    WaitingForOpen,
+    WaitingForPut,
+    Finished
+  } mState;
+
+  uint32_t mPendingCount;
+  OnFailure mOnFailure;
+  bool mAreScriptsEqual;
+};
+
+NS_IMPL_ISUPPORTS0(CompareManager)
+
+nsresult CompareNetwork::Initialize(nsIPrincipal* aPrincipal,
+                                    const nsAString& aURL,
+                                    Cache* const aCache) {
+  MOZ_ASSERT(aPrincipal);
+  MOZ_ASSERT(NS_IsMainThread());
+
+  nsCOMPtr<nsIURI> uri;
+  nsresult rv = NS_NewURI(getter_AddRefs(uri), aURL);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  mURL = aURL;
+  mURLList.AppendElement(NS_ConvertUTF16toUTF8(mURL));
+
+  nsCOMPtr<nsILoadGroup> loadGroup;
+  rv = NS_NewLoadGroup(getter_AddRefs(loadGroup), aPrincipal);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  // Update LoadFlags for propagating to ServiceWorkerInfo.
+  mLoadFlags = nsIChannel::LOAD_BYPASS_SERVICE_WORKER;
+
+  ServiceWorkerUpdateViaCache uvc = mRegistration->GetUpdateViaCache();
+  if (uvc == ServiceWorkerUpdateViaCache::None ||
+      (uvc == ServiceWorkerUpdateViaCache::Imports && mIsMainScript)) {
+    mLoadFlags |= nsIRequest::VALIDATE_ALWAYS;
+  }
+
+  if (mRegistration->IsLastUpdateCheckTimeOverOneDay()) {
+    mLoadFlags |= nsIRequest::LOAD_BYPASS_CACHE;
+  }
+
+  // Different settings are needed for fetching imported scripts, since they
+  // might be cross-origin scripts.
+  uint32_t secFlags =
+      mIsMainScript ? nsILoadInfo::SEC_REQUIRE_SAME_ORIGIN_DATA_IS_BLOCKED
+                    : nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_INHERITS_SEC_CONTEXT;
+
+  nsContentPolicyType contentPolicyType =
+      mIsMainScript ? nsIContentPolicy::TYPE_INTERNAL_SERVICE_WORKER
+                    : nsIContentPolicy::TYPE_INTERNAL_WORKER_IMPORT_SCRIPTS;
+
+  // Create a new cookieJarSettings.
+  nsCOMPtr<nsICookieJarSettings> cookieJarSettings =
+      mozilla::net::CookieJarSettings::Create();
+
+  net::CookieJarSettings::Cast(cookieJarSettings)->SetPartitionKey(uri);
+
+  // Note that because there is no "serviceworker" RequestContext type, we can
+  // use the TYPE_INTERNAL_SCRIPT content policy types when loading a service
+  // worker.
+  rv = NS_NewChannel(getter_AddRefs(mChannel), uri, aPrincipal, secFlags,
+                     contentPolicyType, cookieJarSettings,
+                     nullptr /* aPerformanceStorage */, loadGroup,
+                     nullptr /* aCallbacks */, mLoadFlags);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  nsCOMPtr<nsIHttpChannel> httpChannel = do_QueryInterface(mChannel);
+  if (httpChannel) {
+    // Spec says no redirects allowed for top-level SW scripts.
+    if (mIsMainScript) {
+      rv = httpChannel->SetRedirectionLimit(0);
+      MOZ_ASSERT(NS_SUCCEEDED(rv));
+    }
+
+    rv = httpChannel->SetRequestHeader("Service-Worker"_ns, "script"_ns,
+                                       /* merge */ false);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+  }
+
+  nsCOMPtr<nsIStreamLoader> loader;
+  rv = NS_NewStreamLoader(getter_AddRefs(loader), this, this);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  rv = mChannel->AsyncOpen(loader);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  // If we do have an existing cache to compare with.
+  if (aCache) {
+    mCC = new CompareCache(this);
+    rv = mCC->Initialize(aCache, aURL);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      Abort();
+      return rv;
+    }
+
+    mState = WaitingForBothFinished;
+    return NS_OK;
+  }
+
+  mState = WaitingForNetworkFinished;
+  return NS_OK;
+}
+
+void CompareNetwork::Finish() {
+  if (mState == Finished) {
+    return;
+  }
+
+  bool same = true;
+  nsresult rv = NS_OK;
+
+  // mNetworkResult is prior to mCacheResult, since it's needed for reporting
+  // various errors to web content.
+  if (NS_FAILED(mNetworkResult)) {
+    // An imported script could become offline, since it might no longer be
+    // needed by the new importing script. In that case, the importing script
+    // must be different, and thus, it's okay to report same script found here.
+    rv = mIsMainScript ? mNetworkResult : NS_OK;
+    same = true;
+  } else if (mCC && NS_FAILED(mCacheResult)) {
+    rv = mCacheResult;
+  } else {  // Both passed.
+    same = mCC && mCC->InCache() && mCC->Buffer().Equals(mBuffer);
+  }
+
+  mManager->ComparisonFinished(rv, mIsMainScript, same, mMaxScope, mLoadFlags);
+
+  // We have done with the CompareCache.
+  mCC = nullptr;
+}
+
+void CompareNetwork::NetworkFinish(nsresult aRv) {
+  MOZ_DIAGNOSTIC_ASSERT(mState == WaitingForBothFinished ||
+                        mState == WaitingForNetworkFinished);
+
+  mNetworkResult = aRv;
+
+  if (mState == WaitingForBothFinished) {
+    mState = WaitingForCacheFinished;
+    return;
+  }
+
+  if (mState == WaitingForNetworkFinished) {
+    Finish();
+    return;
+  }
+}
+
+void CompareNetwork::CacheFinish(nsresult aRv) {
+  MOZ_DIAGNOSTIC_ASSERT(mState == WaitingForBothFinished ||
+                        mState == WaitingForCacheFinished);
+
+  mCacheResult = aRv;
+
+  if (mState == WaitingForBothFinished) {
+    mState = WaitingForNetworkFinished;
+    return;
+  }
+
+  if (mState == WaitingForCacheFinished) {
+    Finish();
+    return;
+  }
+}
+
+void CompareNetwork::Abort() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (mState != Finished) {
+    mState = Finished;
+
+    MOZ_ASSERT(mChannel);
+    mChannel->Cancel(NS_BINDING_ABORTED);
+    mChannel = nullptr;
+
+    if (mCC) {
+      mCC->Abort();
+      mCC = nullptr;
+    }
+  }
+}
+
+NS_IMETHODIMP
+CompareNetwork::OnStartRequest(nsIRequest* aRequest) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (mState == Finished) {
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIChannel> channel = do_QueryInterface(aRequest);
+  MOZ_ASSERT_IF(mIsMainScript, channel == mChannel);
+  mChannel = channel;
+
+  MOZ_ASSERT(!mChannelInfo.IsInitialized());
+  mChannelInfo.InitFromChannel(mChannel);
+
+  nsresult rv = SetPrincipalInfo(mChannel);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  mInternalHeaders->FillResponseHeaders(mChannel);
+
+  nsCOMPtr<nsICacheInfoChannel> cacheChannel(do_QueryInterface(channel));
+  if (cacheChannel) {
+    cacheChannel->IsFromCache(&mIsFromCache);
+  }
+
+  return NS_OK;
+}
+
+nsresult CompareNetwork::SetPrincipalInfo(nsIChannel* aChannel) {
+  nsIScriptSecurityManager* ssm = nsContentUtils::GetSecurityManager();
+  if (!ssm) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsCOMPtr<nsIPrincipal> channelPrincipal;
+  nsresult rv = ssm->GetChannelResultPrincipal(
+      aChannel, getter_AddRefs(channelPrincipal));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  UniquePtr<PrincipalInfo> principalInfo = MakeUnique<PrincipalInfo>();
+  rv = PrincipalToPrincipalInfo(channelPrincipal, principalInfo.get());
+
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  mPrincipalInfo = std::move(principalInfo);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+CompareNetwork::OnStopRequest(nsIRequest* aRequest, nsresult aStatusCode) {
+  // Nothing to do here!
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+CompareNetwork::OnStreamComplete(nsIStreamLoader* aLoader,
+                                 nsISupports* aContext, nsresult aStatus,
+                                 uint32_t aLen, const uint8_t* aString) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (mState == Finished) {
+    return NS_OK;
+  }
+
+  nsresult rv = NS_ERROR_FAILURE;
+  auto guard = MakeScopeExit([&] { NetworkFinish(rv); });
+
+  if (NS_WARN_IF(NS_FAILED(aStatus))) {
+    rv = (aStatus == NS_ERROR_REDIRECT_LOOP) ? NS_ERROR_DOM_SECURITY_ERR
+                                             : aStatus;
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIRequest> request;
+  rv = aLoader->GetRequest(getter_AddRefs(request));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIChannel> channel = do_QueryInterface(request);
+  MOZ_ASSERT(channel, "How come we don't have any channel?");
+
+  nsCOMPtr<nsIURI> uri;
+  channel->GetOriginalURI(getter_AddRefs(uri));
+  bool isExtension = uri->SchemeIs("moz-extension");
+
+  if (isExtension &&
+      !StaticPrefs::extensions_backgroundServiceWorker_enabled_AtStartup()) {
+    // Return earlier with error is the worker script is a moz-extension url
+    // but the feature isn't enabled by prefs.
+    return NS_ERROR_FAILURE;
+  }
+
+  if (isExtension) {
+    // NOTE: trying to register any moz-extension use that doesn't ends
+    // with .js/.jsm/.mjs seems to be already completing with an error
+    // in aStatus and they never reach this point.
+
+    // TODO: look into avoid duplicated parts that could be shared with the HTTP
+    // channel scenario.
+    nsCOMPtr<nsIURI> channelURL;
+    rv = channel->GetURI(getter_AddRefs(channelURL));
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+
+    nsCString channelURLSpec;
+    MOZ_ALWAYS_SUCCEEDS(channelURL->GetSpec(channelURLSpec));
+
+    // Append the final URL (which for an extension worker script is going to
+    // be a file or jar url).
+    MOZ_DIAGNOSTIC_ASSERT(!mURLList.IsEmpty());
+    if (channelURLSpec != mURLList[0]) {
+      mURLList.AppendElement(channelURLSpec);
+    }
+
+    char16_t* buffer = nullptr;
+    size_t len = 0;
+
+    rv = ScriptLoader::ConvertToUTF16(channel, aString, aLen, u"UTF-8"_ns,
+                                      nullptr, buffer, len);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+
+    mBuffer.Adopt(buffer, len);
+
+    rv = NS_OK;
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIHttpChannel> httpChannel = do_QueryInterface(request);
+
+  // Main scripts cannot be redirected successfully, however extensions
+  // may successfuly redirect imported scripts to a moz-extension url
+  // (if listed in the web_accessible_resources manifest property).
+  //
+  // When the service worker is initially registered the imported scripts
+  // will be loaded from the child process (see dom/workers/ScriptLoader.cpp)
+  // and in that case this method will only be called for the main script.
+  //
+  // When a registered worker is loaded again (e.g. when the webpage calls
+  // the ServiceWorkerRegistration's update method):
+  //
+  // - both the main and imported scripts are loaded by the
+  //   CompareManager::FetchScript
+  // - the update requests for the imported scripts will also be calling this
+  //   method and we should expect scripts redirected to an extension script
+  //   to have a null httpChannel.
+  //
+  // The request that triggers this method is:
+  //
+  // - the one that is coming from the network (which may be intercepted by
+  //   WebRequest listeners in extensions and redirected to a web_accessible
+  //   moz-extension url)
+  // - it will then be compared with a previous response that we may have
+  //   in the cache
+  //
+  // When the next service worker update occurs, if the request (for an imported
+  // script) is not redirected by an extension the cache entry is invalidated
+  // and a network request is triggered for the import.
+  if (!httpChannel) {
+    // Redirecting a service worker main script should fail before reaching this
+    // method.
+    // If a main script is somehow redirected, the diagnostic assert will crash
+    // in non-release builds.  Release builds will return an explicit error.
+    MOZ_DIAGNOSTIC_ASSERT(!mIsMainScript,
+                          "Unexpected ServiceWorker main script redirected");
+    if (mIsMainScript) {
+      return NS_ERROR_UNEXPECTED;
+    }
+
+    nsCOMPtr<nsIPrincipal> channelPrincipal;
+
+    nsIScriptSecurityManager* ssm = nsContentUtils::GetSecurityManager();
+    if (!ssm) {
+      return NS_ERROR_UNEXPECTED;
+    }
+
+    nsresult rv = ssm->GetChannelResultPrincipal(
+        channel, getter_AddRefs(channelPrincipal));
+
+    // An extension did redirect a non-MainScript request to a moz-extension url
+    // (in that case the originalURL is the resolved jar URI and so we have to
+    // look to the channel principal instead).
+    if (channelPrincipal->SchemeIs("moz-extension")) {
+      char16_t* buffer = nullptr;
+      size_t len = 0;
+
+      rv = ScriptLoader::ConvertToUTF16(channel, aString, aLen, u"UTF-8"_ns,
+                                        nullptr, buffer, len);
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return rv;
+      }
+
+      mBuffer.Adopt(buffer, len);
+
+      return NS_OK;
+    }
+
+    // Make non-release and debug builds to crash if this happens and fail
+    // explicitly on release builds.
+    MOZ_DIAGNOSTIC_ASSERT(false,
+                          "ServiceWorker imported script redirected to an url "
+                          "with an unexpected scheme");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  bool requestSucceeded;
+  rv = httpChannel->GetRequestSucceeded(&requestSucceeded);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return NS_OK;
+  }
+
+  if (NS_WARN_IF(!requestSucceeded)) {
+    // Get the stringified numeric status code, not statusText which could be
+    // something misleading like OK for a 404.
+    uint32_t status = 0;
+    Unused << httpChannel->GetResponseStatus(
+        &status);  // don't care if this fails, use 0.
+    nsAutoString statusAsText;
+    statusAsText.AppendInt(status);
+
+    ServiceWorkerManager::LocalizeAndReportToAllClients(
+        mRegistration->Scope(), "ServiceWorkerRegisterNetworkError",
+        nsTArray<nsString>{NS_ConvertUTF8toUTF16(mRegistration->Scope()),
+                           statusAsText, mURL});
+
+    rv = NS_ERROR_FAILURE;
+    return NS_OK;
+  }
+
+  // Note: we explicitly don't check for the return value here, because the
+  // absence of the header is not an error condition.
+  Unused << httpChannel->GetResponseHeader("Service-Worker-Allowed"_ns,
+                                           mMaxScope);
+
+  // [9.2 Update]4.13, If response's cache state is not "local",
+  // set registration's last update check time to the current time
+  if (!mIsFromCache) {
+    mRegistration->RefreshLastUpdateCheckTime();
+  }
+
+  nsAutoCString mimeType;
+  rv = httpChannel->GetContentType(mimeType);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    // We should only end up here if !mResponseHead in the channel.  If headers
+    // were received but no content type was specified, we'll be given
+    // UNKNOWN_CONTENT_TYPE "application/x-unknown-content-type" and so fall
+    // into the next case with its better error message.
+    rv = NS_ERROR_DOM_SECURITY_ERR;
+    return rv;
+  }
+
+  if (mimeType.IsEmpty() ||
+      !nsContentUtils::IsJavascriptMIMEType(NS_ConvertUTF8toUTF16(mimeType))) {
+    ServiceWorkerManager::LocalizeAndReportToAllClients(
+        mRegistration->Scope(), "ServiceWorkerRegisterMimeTypeError2",
+        nsTArray<nsString>{NS_ConvertUTF8toUTF16(mRegistration->Scope()),
+                           NS_ConvertUTF8toUTF16(mimeType), mURL});
+    rv = NS_ERROR_DOM_SECURITY_ERR;
+    return rv;
+  }
+
+  nsCOMPtr<nsIURI> channelURL;
+  rv = httpChannel->GetURI(getter_AddRefs(channelURL));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  nsCString channelURLSpec;
+  MOZ_ALWAYS_SUCCEEDS(channelURL->GetSpec(channelURLSpec));
+
+  // Append the final URL if its different from the original
+  // request URL.  This lets us note that a redirect occurred
+  // even though we don't track every redirect URL here.
+  MOZ_DIAGNOSTIC_ASSERT(!mURLList.IsEmpty());
+  if (channelURLSpec != mURLList[0]) {
+    mURLList.AppendElement(channelURLSpec);
+  }
+
+  char16_t* buffer = nullptr;
+  size_t len = 0;
+
+  rv = ScriptLoader::ConvertToUTF16(httpChannel, aString, aLen, u"UTF-8"_ns,
+                                    nullptr, buffer, len);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  mBuffer.Adopt(buffer, len);
+
+  rv = NS_OK;
+  return NS_OK;
+}
+
+nsresult CompareCache::Initialize(Cache* const aCache, const nsAString& aURL) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aCache);
+  MOZ_DIAGNOSTIC_ASSERT(mState == WaitingForInitialization);
+
+  // This JSContext will not end up executing JS code because here there are
+  // no ReadableStreams involved.
+  AutoJSAPI jsapi;
+  jsapi.Init();
+
+  RequestOrUSVString request;
+  request.SetAsUSVString().ShareOrDependUpon(aURL);
+  ErrorResult error;
+  CacheQueryOptions params;
+  RefPtr<Promise> promise = aCache->Match(jsapi.cx(), request, params, error);
+  if (NS_WARN_IF(error.Failed())) {
+    // No exception here because there are no ReadableStreams involved here.
+    MOZ_ASSERT(!error.IsJSException());
+    mState = Finished;
+    return error.StealNSResult();
+  }
+
+  // Retrieve the script from aCache.
+  mState = WaitingForScript;
+  promise->AppendNativeHandler(this);
+  return NS_OK;
+}
+
+void CompareCache::Finish(nsresult aStatus, bool aInCache) {
+  if (mState != Finished) {
+    mState = Finished;
+    mInCache = aInCache;
+    mCN->CacheFinish(aStatus);
+  }
+}
+
+void CompareCache::Abort() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (mState != Finished) {
+    mState = Finished;
+
+    if (mPump) {
+      mPump->Cancel(NS_BINDING_ABORTED);
+      mPump = nullptr;
+    }
+  }
+}
+
+NS_IMETHODIMP
+CompareCache::OnStreamComplete(nsIStreamLoader* aLoader, nsISupports* aContext,
+                               nsresult aStatus, uint32_t aLen,
+                               const uint8_t* aString) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (mState == Finished) {
+    return aStatus;
+  }
+
+  if (NS_WARN_IF(NS_FAILED(aStatus))) {
+    Finish(aStatus, false);
+    return aStatus;
+  }
+
+  char16_t* buffer = nullptr;
+  size_t len = 0;
+
+  nsresult rv = ScriptLoader::ConvertToUTF16(nullptr, aString, aLen,
+                                             u"UTF-8"_ns, nullptr, buffer, len);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    Finish(rv, false);
+    return rv;
+  }
+
+  mBuffer.Adopt(buffer, len);
+
+  Finish(NS_OK, true);
+  return NS_OK;
+}
+
+void CompareCache::ResolvedCallback(JSContext* aCx,
+                                    JS::Handle<JS::Value> aValue) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  switch (mState) {
+    case Finished:
+      return;
+    case WaitingForScript:
+      ManageValueResult(aCx, aValue);
+      return;
+    default:
+      MOZ_CRASH("Unacceptable state.");
+  }
+}
+
+void CompareCache::RejectedCallback(JSContext* aCx,
+                                    JS::Handle<JS::Value> aValue) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (mState != Finished) {
+    Finish(NS_ERROR_FAILURE, false);
+    return;
+  }
+}
+
+void CompareCache::ManageValueResult(JSContext* aCx,
+                                     JS::Handle<JS::Value> aValue) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // The cache returns undefined if the object is not stored.
+  if (aValue.isUndefined()) {
+    Finish(NS_OK, false);
+    return;
+  }
+
+  MOZ_ASSERT(aValue.isObject());
+
+  JS::Rooted<JSObject*> obj(aCx, &aValue.toObject());
+  if (NS_WARN_IF(!obj)) {
+    Finish(NS_ERROR_FAILURE, false);
+    return;
+  }
+
+  Response* response = nullptr;
+  nsresult rv = UNWRAP_OBJECT(Response, &obj, response);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    Finish(rv, false);
+    return;
+  }
+
+  MOZ_ASSERT(response->Ok());
+
+  nsCOMPtr<nsIInputStream> inputStream;
+  response->GetBody(getter_AddRefs(inputStream));
+  MOZ_ASSERT(inputStream);
+
+  MOZ_ASSERT(!mPump);
+  rv = NS_NewInputStreamPump(getter_AddRefs(mPump), inputStream.forget(),
+                             0,     /* default segsize */
+                             0,     /* default segcount */
+                             false, /* default closeWhenDone */
+                             GetMainThreadSerialEventTarget());
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    Finish(rv, false);
+    return;
+  }
+
+  nsCOMPtr<nsIStreamLoader> loader;
+  rv = NS_NewStreamLoader(getter_AddRefs(loader), this);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    Finish(rv, false);
+    return;
+  }
+
+  rv = mPump->AsyncRead(loader);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    mPump = nullptr;
+    Finish(rv, false);
+    return;
+  }
+
+  nsCOMPtr<nsIThreadRetargetableRequest> rr = do_QueryInterface(mPump);
+  if (rr) {
+    nsCOMPtr<nsIEventTarget> sts =
+        do_GetService(NS_STREAMTRANSPORTSERVICE_CONTRACTID);
+    rv = rr->RetargetDeliveryTo(sts);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      mPump = nullptr;
+      Finish(rv, false);
+      return;
+    }
+  }
+}
+
+nsresult CompareManager::Initialize(nsIPrincipal* aPrincipal,
+                                    const nsAString& aURL,
+                                    const nsAString& aCacheName) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aPrincipal);
+  MOZ_ASSERT(mPendingCount == 0);
+  MOZ_DIAGNOSTIC_ASSERT(mState == WaitingForInitialization);
+
+  // RAII Cleanup when fails.
+  auto guard = MakeScopeExit([&] { Cleanup(); });
+
+  mURL = aURL;
+  mPrincipal = aPrincipal;
+
+  // Always create a CacheStorage since we want to write the network entry to
+  // the cache even if there isn't an existing one.
+  AutoJSAPI jsapi;
+  jsapi.Init();
+  ErrorResult result;
+  mCacheStorage = CreateCacheStorage(jsapi.cx(), aPrincipal, result);
+  if (NS_WARN_IF(result.Failed())) {
+    MOZ_ASSERT(!result.IsErrorWithMessage());
+    return result.StealNSResult();
+  }
+
+  // If there is no existing cache, proceed to fetch the script directly.
+  if (aCacheName.IsEmpty()) {
+    mState = WaitingForScriptOrComparisonResult;
+    nsresult rv = FetchScript(aURL, true /* aIsMainScript */);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+
+    guard.release();
+    return NS_OK;
+  }
+
+  // Open the cache saving the old source scripts.
+  RefPtr<Promise> promise = mCacheStorage->Open(aCacheName, result);
+  if (NS_WARN_IF(result.Failed())) {
+    MOZ_ASSERT(!result.IsErrorWithMessage());
+    return result.StealNSResult();
+  }
+
+  mState = WaitingForExistingOpen;
+  promise->AppendNativeHandler(this);
+
+  guard.release();
+  return NS_OK;
+}
+
+// This class manages 4 promises if needed:
+// 1. Retrieve the Cache object by a given CacheName of OldCache.
+// 2. Retrieve the URLs saved in OldCache.
+// 3. Retrieve the Cache object of the NewCache for the newly created SW.
+// 4. Put the value in the cache.
+// For this reason we have mState to know what callback we are handling.
+void CompareManager::ResolvedCallback(JSContext* aCx,
+                                      JS::Handle<JS::Value> aValue) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(mCallback);
+
+  switch (mState) {
+    case Finished:
+      return;
+    case WaitingForExistingOpen:
+      ManageOldCache(aCx, aValue);
+      return;
+    case WaitingForExistingKeys:
+      ManageOldKeys(aCx, aValue);
+      return;
+    case WaitingForOpen:
+      ManageNewCache(aCx, aValue);
+      return;
+    case WaitingForPut:
+      MOZ_DIAGNOSTIC_ASSERT(mPendingCount > 0);
+      if (--mPendingCount == 0) {
+        mCallback->ComparisonResult(NS_OK, false /* aIsEqual */, mOnFailure,
+                                    mNewCacheName, mMaxScope, mLoadFlags);
+        Cleanup();
+      }
+      return;
+    default:
+      MOZ_DIAGNOSTIC_ASSERT(false);
+  }
+}
+
+void CompareManager::RejectedCallback(JSContext* aCx,
+                                      JS::Handle<JS::Value> aValue) {
+  MOZ_ASSERT(NS_IsMainThread());
+  switch (mState) {
+    case Finished:
+      return;
+    case WaitingForExistingOpen:
+      NS_WARNING("Could not open the existing cache.");
+      break;
+    case WaitingForExistingKeys:
+      NS_WARNING("Could not get the existing URLs.");
+      break;
+    case WaitingForOpen:
+      NS_WARNING("Could not open cache.");
+      break;
+    case WaitingForPut:
+      NS_WARNING("Could not write to cache.");
+      break;
+    default:
+      MOZ_DIAGNOSTIC_ASSERT(false);
+  }
+
+  Fail(NS_ERROR_FAILURE);
+}
+
+void CompareManager::Fail(nsresult aStatus) {
+  MOZ_ASSERT(NS_IsMainThread());
+  mCallback->ComparisonResult(aStatus, false /* aIsEqual */, mOnFailure, u""_ns,
+                              ""_ns, mLoadFlags);
+  Cleanup();
+}
+
+void CompareManager::Cleanup() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (mState != Finished) {
+    mState = Finished;
+
+    MOZ_ASSERT(mCallback);
+    mCallback = nullptr;
+
+    // Abort and release CompareNetworks.
+    for (uint32_t i = 0; i < mCNList.Length(); ++i) {
+      mCNList[i]->Abort();
+    }
+    mCNList.Clear();
+  }
+}
+
+class NoopPromiseHandler final : public PromiseNativeHandler {
+ public:
+  NS_DECL_ISUPPORTS
+
+  NoopPromiseHandler() { AssertIsOnMainThread(); }
+
+  void ResolvedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue) override {
+  }
+  void RejectedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue) override {
+  }
+
+ private:
+  ~NoopPromiseHandler() { AssertIsOnMainThread(); }
+};
+
+NS_IMPL_ISUPPORTS0(NoopPromiseHandler)
+
+}  // namespace
+
+nsresult PurgeCache(nsIPrincipal* aPrincipal, const nsAString& aCacheName) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aPrincipal);
+
+  if (aCacheName.IsEmpty()) {
+    return NS_OK;
+  }
+
+  AutoJSAPI jsapi;
+  jsapi.Init();
+  ErrorResult rv;
+  RefPtr<CacheStorage> cacheStorage =
+      CreateCacheStorage(jsapi.cx(), aPrincipal, rv);
+  if (NS_WARN_IF(rv.Failed())) {
+    return rv.StealNSResult();
+  }
+
+  // We use the ServiceWorker scope as key for the cacheStorage.
+  RefPtr<Promise> promise = cacheStorage->Delete(aCacheName, rv);
+  if (NS_WARN_IF(rv.Failed())) {
+    return rv.StealNSResult();
+  }
+
+  // Add a no-op promise handler to ensure that if this promise gets rejected,
+  // we don't end up reporting a rejected promise to the console.
+  RefPtr<NoopPromiseHandler> promiseHandler = new NoopPromiseHandler();
+  promise->AppendNativeHandler(promiseHandler);
+
+  // We don't actually care about the result of the delete operation.
+  return NS_OK;
+}
+
+nsresult GenerateCacheName(nsAString& aName) {
+  nsresult rv;
+  nsCOMPtr<nsIUUIDGenerator> uuidGenerator =
+      do_GetService("@mozilla.org/uuid-generator;1", &rv);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  nsID id;
+  rv = uuidGenerator->GenerateUUIDInPlace(&id);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  char chars[NSID_LENGTH];
+  id.ToProvidedString(chars);
+
+  // NSID_LENGTH counts the null terminator.
+  aName.AssignASCII(chars, NSID_LENGTH - 1);
+
+  return NS_OK;
+}
+
+nsresult Compare(ServiceWorkerRegistrationInfo* aRegistration,
+                 nsIPrincipal* aPrincipal, const nsAString& aCacheName,
+                 const nsAString& aURL, CompareCallback* aCallback) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aRegistration);
+  MOZ_ASSERT(aPrincipal);
+  MOZ_ASSERT(!aURL.IsEmpty());
+  MOZ_ASSERT(aCallback);
+
+  RefPtr<CompareManager> cm = new CompareManager(aRegistration, aCallback);
+
+  nsresult rv = cm->Initialize(aPrincipal, aURL, aCacheName);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+}  // namespace serviceWorkerScriptCache
+
+}  // namespace dom
+}  // namespace mozilla