Adding upstream version 110.0.1.upstream/110.0.1upstream

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

1 files changed, 796 insertions, 0 deletions

diff --git a/netwerk/protocol/http/EarlyHintPreloader.cpp b/netwerk/protocol/http/EarlyHintPreloader.cpp
new file mode 100644
index 0000000000..7cb989b920
--- /dev/null
+++ b/netwerk/protocol/http/EarlyHintPreloader.cpp
@@ -0,0 +1,796 @@
+/* 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 "EarlyHintPreloader.h"
+
+#include "EarlyHintRegistrar.h"
+#include "EarlyHintsService.h"
+#include "ErrorList.h"
+#include "HttpChannelParent.h"
+#include "MainThreadUtils.h"
+#include "NeckoCommon.h"
+#include "mozilla/CORSMode.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/dom/nsCSPContext.h"
+#include "mozilla/dom/ReferrerInfo.h"
+#include "mozilla/glean/GleanMetrics.h"
+#include "mozilla/ipc/BackgroundUtils.h"
+#include "mozilla/LoadInfo.h"
+#include "mozilla/Logging.h"
+#include "mozilla/net/EarlyHintRegistrar.h"
+#include "mozilla/net/NeckoChannelParams.h"
+#include "mozilla/StaticPrefs_network.h"
+#include "mozilla/Telemetry.h"
+#include "nsAttrValue.h"
+#include "nsAttrValueInlines.h"
+#include "nsCOMPtr.h"
+#include "nsContentPolicyUtils.h"
+#include "nsContentSecurityManager.h"
+#include "nsContentUtils.h"
+#include "nsDebug.h"
+#include "nsHttpChannel.h"
+#include "nsIAsyncVerifyRedirectCallback.h"
+#include "nsIChannel.h"
+#include "nsIContentSecurityPolicy.h"
+#include "nsIHttpChannel.h"
+#include "nsIInputStream.h"
+#include "nsILoadInfo.h"
+#include "nsIParentChannel.h"
+#include "nsIReferrerInfo.h"
+#include "nsITimer.h"
+#include "nsIURI.h"
+#include "nsNetUtil.h"
+#include "nsQueryObject.h"
+#include "nsStreamUtils.h"
+#include "nsStringStream.h"
+#include "ParentChannelListener.h"
+#include "nsIChannel.h"
+
+//
+// To enable logging (see mozilla/Logging.h for full details):
+//
+//    set MOZ_LOG=EarlyHint:5
+//    set MOZ_LOG_FILE=earlyhint.log
+//
+// this enables LogLevel::Debug level information and places all output in
+// the file earlyhint.log
+//
+static mozilla::LazyLogModule gEarlyHintLog("EarlyHint");
+
+#undef LOG
+#define LOG(args) MOZ_LOG(gEarlyHintLog, mozilla::LogLevel::Debug, args)
+
+#undef LOG_ENABLED
+#define LOG_ENABLED() MOZ_LOG_TEST(gEarlyHintLog, mozilla::LogLevel::Debug)
+
+namespace mozilla::net {
+
+namespace {
+// This id uniquely identifies each early hint preloader in the
+// EarlyHintRegistrar. Must only be accessed from main thread.
+static uint64_t gEarlyHintPreloaderId{0};
+}  // namespace
+
+//=============================================================================
+// OngoingEarlyHints
+//=============================================================================
+
+void OngoingEarlyHints::CancelAllOngoingPreloads(const nsACString& aReason) {
+  for (auto& preloader : mPreloaders) {
+    preloader->CancelChannel(NS_ERROR_ABORT, aReason, /* aDeleteEntry */ true);
+  }
+  mPreloaders.Clear();
+  mStartedPreloads.Clear();
+}
+
+bool OngoingEarlyHints::Contains(const PreloadHashKey& aKey) {
+  return mStartedPreloads.Contains(aKey);
+}
+
+bool OngoingEarlyHints::Add(const PreloadHashKey& aKey,
+                            RefPtr<EarlyHintPreloader> aPreloader) {
+  if (!mStartedPreloads.Contains(aKey)) {
+    mStartedPreloads.Insert(aKey);
+    mPreloaders.AppendElement(aPreloader);
+    return true;
+  }
+  return false;
+}
+
+void OngoingEarlyHints::RegisterLinksAndGetConnectArgs(
+    nsTArray<EarlyHintConnectArgs>& aOutLinks) {
+  // register all channels before returning
+  for (auto& preload : mPreloaders) {
+    EarlyHintConnectArgs args;
+    if (preload->Register(args)) {
+      aOutLinks.AppendElement(std::move(args));
+    }
+  }
+}
+
+//=============================================================================
+// EarlyHintPreloader
+//=============================================================================
+
+EarlyHintPreloader::EarlyHintPreloader() {
+  AssertIsOnMainThread();
+  mConnectArgs.earlyHintPreloaderId() = ++gEarlyHintPreloaderId;
+};
+
+EarlyHintPreloader::~EarlyHintPreloader() {
+  if (mTimer) {
+    mTimer->Cancel();
+    mTimer = nullptr;
+  }
+  Telemetry::Accumulate(Telemetry::EH_STATE_OF_PRELOAD_REQUEST, mState);
+}
+
+/* static */
+Maybe<PreloadHashKey> EarlyHintPreloader::GenerateHashKey(
+    ASDestination aAs, nsIURI* aURI, nsIPrincipal* aPrincipal,
+    CORSMode aCorsMode, const nsAString& aType) {
+  if (aAs == ASDestination::DESTINATION_FONT && aCorsMode != CORS_NONE) {
+    return Some(PreloadHashKey::CreateAsFont(aURI, aCorsMode));
+  }
+  if (aAs == ASDestination::DESTINATION_IMAGE) {
+    return Some(PreloadHashKey::CreateAsImage(aURI, aPrincipal, aCorsMode));
+  }
+  if (aAs == ASDestination::DESTINATION_SCRIPT &&
+      !aType.LowerCaseEqualsASCII("module")) {
+    return Some(PreloadHashKey::CreateAsScript(
+        aURI, aCorsMode, JS::loader::ScriptKind::eClassic));
+  }
+  if (aAs == ASDestination::DESTINATION_STYLE) {
+    return Some(PreloadHashKey::CreateAsStyle(
+        aURI, aPrincipal, aCorsMode,
+        css::SheetParsingMode::eAuthorSheetFeatures));
+  }
+  if (aAs == ASDestination::DESTINATION_FETCH && aCorsMode != CORS_NONE) {
+    return Some(PreloadHashKey::CreateAsFetch(aURI, aCorsMode));
+  }
+  return Nothing();
+}
+
+/* static */
+nsSecurityFlags EarlyHintPreloader::ComputeSecurityFlags(CORSMode aCORSMode,
+                                                         ASDestination aAs,
+                                                         bool aIsModule) {
+  if (aAs == ASDestination::DESTINATION_FONT) {
+    return nsContentSecurityManager::ComputeSecurityFlags(
+        CORSMode::CORS_NONE,
+        nsContentSecurityManager::CORSSecurityMapping::REQUIRE_CORS_CHECKS);
+  }
+  if (aAs == ASDestination::DESTINATION_IMAGE) {
+    return nsContentSecurityManager::ComputeSecurityFlags(
+               aCORSMode, nsContentSecurityManager::CORSSecurityMapping::
+                              CORS_NONE_MAPS_TO_INHERITED_CONTEXT) |
+           nsILoadInfo::SEC_ALLOW_CHROME;
+  }
+  if (aAs == ASDestination::DESTINATION_SCRIPT) {
+    if (aIsModule) {
+      return nsContentSecurityManager::ComputeSecurityFlags(
+                 aCORSMode, nsContentSecurityManager::CORSSecurityMapping::
+                                REQUIRE_CORS_CHECKS) |
+             nsILoadInfo::SEC_ALLOW_CHROME;
+    }
+    return nsContentSecurityManager::ComputeSecurityFlags(
+               aCORSMode, nsContentSecurityManager::CORSSecurityMapping::
+                              CORS_NONE_MAPS_TO_DISABLED_CORS_CHECKS) |
+           nsILoadInfo::SEC_ALLOW_CHROME;
+  }
+  if (aAs == ASDestination::DESTINATION_STYLE) {
+    return nsContentSecurityManager::ComputeSecurityFlags(
+               aCORSMode, nsContentSecurityManager::CORSSecurityMapping::
+                              CORS_NONE_MAPS_TO_INHERITED_CONTEXT) |
+           nsILoadInfo::SEC_ALLOW_CHROME;
+    ;
+  }
+  if (aAs == ASDestination::DESTINATION_FETCH) {
+    return nsContentSecurityManager::ComputeSecurityFlags(
+        aCORSMode, nsContentSecurityManager::CORSSecurityMapping::
+                       CORS_NONE_MAPS_TO_DISABLED_CORS_CHECKS);
+  }
+  MOZ_ASSERT(false, "Unexpected ASDestination");
+  return nsContentSecurityManager::ComputeSecurityFlags(
+      CORSMode::CORS_NONE,
+      nsContentSecurityManager::CORSSecurityMapping::REQUIRE_CORS_CHECKS);
+}
+
+// static
+void EarlyHintPreloader::MaybeCreateAndInsertPreload(
+    OngoingEarlyHints* aOngoingEarlyHints, const LinkHeader& aLinkHeader,
+    nsIURI* aBaseURI, nsIPrincipal* aPrincipal,
+    nsICookieJarSettings* aCookieJarSettings,
+    const nsACString& aResponseReferrerPolicy, const nsACString& aCSPHeader) {
+  nsAttrValue as;
+  ParseAsValue(aLinkHeader.mAs, as);
+
+  ASDestination destination = static_cast<ASDestination>(as.GetEnumValue());
+  CollectResourcesTypeTelemetry(destination);
+
+  if (!StaticPrefs::network_early_hints_enabled()) {
+    return;
+  }
+
+  if (as.GetEnumValue() == ASDestination::DESTINATION_INVALID) {
+    // return early when it's definitly not an asset type we preload
+    // would be caught later as well, e.g. when creating the PreloadHashKey
+    return;
+  }
+
+  nsCOMPtr<nsIURI> uri;
+  NS_ENSURE_SUCCESS_VOID(
+      NS_NewURI(getter_AddRefs(uri), aLinkHeader.mHref, nullptr, aBaseURI));
+  // The link relation may apply to a different resource, specified
+  // in the anchor parameter. For the link relations supported so far,
+  // we simply abort if the link applies to a resource different to the
+  // one we've loaded
+  if (!nsContentUtils::LinkContextIsURI(aLinkHeader.mAnchor, uri)) {
+    return;
+  }
+
+  // only preload secure context urls
+  if (!uri->SchemeIs("https")) {
+    return;
+  }
+
+  CORSMode corsMode = dom::Element::StringToCORSMode(aLinkHeader.mCrossOrigin);
+
+  Maybe<PreloadHashKey> hashKey =
+      GenerateHashKey(static_cast<ASDestination>(as.GetEnumValue()), uri,
+                      aPrincipal, corsMode, aLinkHeader.mType);
+  if (!hashKey) {
+    return;
+  }
+
+  if (aOngoingEarlyHints->Contains(*hashKey)) {
+    return;
+  }
+
+  nsContentPolicyType contentPolicyType = AsValueToContentPolicy(as);
+  if (contentPolicyType == nsContentPolicyType::TYPE_INVALID) {
+    return;
+  }
+
+  dom::ReferrerPolicy linkReferrerPolicy =
+      dom::ReferrerInfo::ReferrerPolicyAttributeFromString(
+          aLinkHeader.mReferrerPolicy);
+
+  dom::ReferrerPolicy responseReferrerPolicy =
+      dom::ReferrerInfo::ReferrerPolicyAttributeFromString(
+          NS_ConvertUTF8toUTF16(aResponseReferrerPolicy));
+
+  // The early hint may have two referrer policies, one from the response header
+  // and one from the link element.
+  //
+  // For example, in this server response:
+  //   HTTP/1.1 103 Early Hints
+  //   Referrer-Policy : origin
+  //   Link: </style.css>; rel=preload; as=style referrerpolicy=no-referrer
+  //
+  //   The link header referrer policy, if present, will take precedence over
+  //   the response referrer policy
+  dom::ReferrerPolicy finalReferrerPolicy = responseReferrerPolicy;
+  if (linkReferrerPolicy != dom::ReferrerPolicy::_empty) {
+    finalReferrerPolicy = linkReferrerPolicy;
+  }
+  nsCOMPtr<nsIReferrerInfo> referrerInfo =
+      new dom::ReferrerInfo(aBaseURI, finalReferrerPolicy);
+
+  RefPtr<EarlyHintPreloader> earlyHintPreloader = new EarlyHintPreloader();
+
+  nsSecurityFlags securityFlags = EarlyHintPreloader::ComputeSecurityFlags(
+      corsMode, static_cast<ASDestination>(as.GetEnumValue()),
+      aLinkHeader.mType.LowerCaseEqualsASCII("module"));
+
+  // Verify that the resource should be loaded.
+  // This isn't the ideal way to test the resource against the CSP.
+  // The problem comes from the fact that at the stage of Early Hint
+  // processing we have not yet created a document where we would normally store
+  // the CSP.
+
+  // First we will create a load info,
+  // nsILoadInfo::SEC_ONLY_FOR_EXPLICIT_CONTENTSEC_CHECK
+  nsCOMPtr<nsILoadInfo> secCheckLoadInfo = new LoadInfo(
+      aPrincipal,  // loading principal
+      aPrincipal,  // triggering principal
+      nullptr /* aLoadingContext node */,
+      nsILoadInfo::SEC_ONLY_FOR_EXPLICIT_CONTENTSEC_CHECK, contentPolicyType);
+
+  if (aCSPHeader.Length() != 0) {
+    // If the CSP header is present then create a new CSP and apply the header
+    // directives to it
+    nsCOMPtr<nsIContentSecurityPolicy> csp = new nsCSPContext();
+    nsresult rv = csp->SetRequestContextWithPrincipal(
+        aPrincipal, aBaseURI, u""_ns, 0 /* aInnerWindowId */);
+    NS_ENSURE_SUCCESS_VOID(rv);
+    rv = CSP_AppendCSPFromHeader(csp, NS_ConvertUTF8toUTF16(aCSPHeader),
+                                 false /* report only */);
+    NS_ENSURE_SUCCESS_VOID(rv);
+
+    // We create a temporary ClientInfo. This is required on the loadInfo as
+    // that is how the CSP is queried. More specificially, as a hack to be able
+    // to call NS_CheckContentLoadPolicy on nsILoadInfo which exclusively
+    // accesses the CSP from the ClientInfo, we create a synthetic ClientInfo to
+    // hold the CSP we are creating. This is not a safe thing to do in any other
+    // circumstance because ClientInfos are always describing a ClientSource
+    // that corresponds to a global or potential global, so creating an info
+    // without a source is unsound. For the purposes of doing things before a
+    // global exists, fetch has the concept of a
+    // https://fetch.spec.whatwg.org/#concept-request-reserved-client and
+    // nsILoadInfo explicity has methods around GiveReservedClientSource which
+    // are primarily used by ClientChannelHelper. If you are trying to do real
+    // CSP stuff and the ClientInfo is not there yet, please enhance the logic
+    // around ClientChannelHelper.
+
+    mozilla::ipc::PrincipalInfo principalInfo;
+    rv = PrincipalToPrincipalInfo(aPrincipal, &principalInfo);
+    NS_ENSURE_SUCCESS_VOID(rv);
+    dom::ClientInfo clientInfo(nsID::GenerateUUID(), dom::ClientType::Window,
+                               principalInfo, TimeStamp::Now());
+
+    // Our newly-created CSP is set on the ClientInfo via the indirect route of
+    // first serializing to CSPInfo
+    ipc::CSPInfo cspInfo;
+    rv = CSPToCSPInfo(csp, &cspInfo);
+    NS_ENSURE_SUCCESS_VOID(rv);
+    clientInfo.SetCspInfo(cspInfo);
+
+    // This ClientInfo is then set on the new loadInfo.
+    // It can now be used to test the resource against the policy
+    secCheckLoadInfo->SetClientInfo(clientInfo);
+  }
+
+  int16_t shouldLoad = nsIContentPolicy::ACCEPT;
+  nsresult rv =
+      NS_CheckContentLoadPolicy(uri, secCheckLoadInfo, ""_ns, &shouldLoad,
+                                nsContentUtils::GetContentPolicy());
+
+  if (NS_FAILED(rv) || NS_CP_REJECTED(shouldLoad)) {
+    return;
+  }
+
+  NS_ENSURE_SUCCESS_VOID(earlyHintPreloader->OpenChannel(
+      uri, aPrincipal, securityFlags, contentPolicyType, referrerInfo,
+      aCookieJarSettings));
+
+  earlyHintPreloader->SetLinkHeader(aLinkHeader);
+
+  DebugOnly<bool> result =
+      aOngoingEarlyHints->Add(*hashKey, earlyHintPreloader);
+  MOZ_ASSERT(result);
+}
+
+nsresult EarlyHintPreloader::OpenChannel(
+    nsIURI* aURI, nsIPrincipal* aPrincipal, nsSecurityFlags aSecurityFlags,
+    nsContentPolicyType aContentPolicyType, nsIReferrerInfo* aReferrerInfo,
+    nsICookieJarSettings* aCookieJarSettings) {
+  MOZ_ASSERT(aContentPolicyType == nsContentPolicyType::TYPE_IMAGE ||
+             aContentPolicyType ==
+                 nsContentPolicyType::TYPE_INTERNAL_FETCH_PRELOAD ||
+             aContentPolicyType == nsContentPolicyType::TYPE_SCRIPT ||
+             aContentPolicyType == nsContentPolicyType::TYPE_STYLESHEET ||
+             aContentPolicyType == nsContentPolicyType::TYPE_FONT);
+
+  nsresult rv =
+      NS_NewChannel(getter_AddRefs(mChannel), aURI, aPrincipal, aSecurityFlags,
+                    aContentPolicyType, aCookieJarSettings,
+                    /* aPerformanceStorage */ nullptr,
+                    /* aLoadGroup */ nullptr,
+                    /* aCallbacks */ this, nsIRequest::LOAD_NORMAL);
+
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  RefPtr<nsHttpChannel> httpChannelObject = do_QueryObject(mChannel);
+  if (!httpChannelObject) {
+    mChannel = nullptr;
+    return NS_ERROR_ABORT;
+  }
+
+  // configure HTTP specific stuff
+  nsCOMPtr<nsIHttpChannel> httpChannel = do_QueryInterface(mChannel);
+  if (!httpChannel) {
+    mChannel = nullptr;
+    return NS_ERROR_ABORT;
+  }
+  DebugOnly<nsresult> success = httpChannel->SetReferrerInfo(aReferrerInfo);
+  MOZ_ASSERT(NS_SUCCEEDED(success));
+  success = httpChannel->SetRequestHeader("X-Moz"_ns, "early hint"_ns, false);
+  MOZ_ASSERT(NS_SUCCEEDED(success));
+
+  mParentListener = new ParentChannelListener(this, nullptr);
+
+  PriorizeAsPreload();
+
+  rv = mChannel->AsyncOpen(mParentListener);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  SetState(ePreloaderOpened);
+
+  return NS_OK;
+}
+
+void EarlyHintPreloader::PriorizeAsPreload() {
+  nsLoadFlags loadFlags = nsIRequest::LOAD_NORMAL;
+  Unused << mChannel->GetLoadFlags(&loadFlags);
+  Unused << mChannel->SetLoadFlags(loadFlags | nsIRequest::LOAD_BACKGROUND);
+
+  if (nsCOMPtr<nsIClassOfService> cos = do_QueryInterface(mChannel)) {
+    Unused << cos->AddClassFlags(nsIClassOfService::Unblocked);
+  }
+}
+
+void EarlyHintPreloader::SetLinkHeader(const LinkHeader& aLinkHeader) {
+  mConnectArgs.link() = aLinkHeader;
+}
+
+bool EarlyHintPreloader::Register(EarlyHintConnectArgs& aOut) {
+  // Set minimum delay of 1ms to always start the timer after the function call
+  // completed.
+  nsresult rv = NS_NewTimerWithCallback(
+      getter_AddRefs(mTimer), this,
+      std::max(StaticPrefs::network_early_hints_parent_connect_timeout(),
+               (uint32_t)1),
+      nsITimer::TYPE_ONE_SHOT);
+  if (NS_FAILED(rv)) {
+    MOZ_ASSERT(!mTimer);
+    CancelChannel(NS_ERROR_ABORT, "new-timer-failed"_ns,
+                  /* aDeleteEntry */ false);
+    return false;
+  }
+
+  // Create an entry in the redirect channel registrar
+  RefPtr<EarlyHintRegistrar> registrar = EarlyHintRegistrar::GetOrCreate();
+  registrar->RegisterEarlyHint(mConnectArgs.earlyHintPreloaderId(), this);
+
+  aOut = mConnectArgs;
+  return true;
+}
+
+nsresult EarlyHintPreloader::CancelChannel(nsresult aStatus,
+                                           const nsACString& aReason,
+                                           bool aDeleteEntry) {
+  LOG(("EarlyHintPreloader::CancelChannel [this=%p]\n", this));
+
+  if (mTimer) {
+    mTimer->Cancel();
+    mTimer = nullptr;
+  }
+  if (aDeleteEntry) {
+    RefPtr<EarlyHintRegistrar> registrar = EarlyHintRegistrar::GetOrCreate();
+    registrar->DeleteEntry(mConnectArgs.earlyHintPreloaderId());
+  }
+  // clear redirect channel in case this channel is cleared between the call of
+  // EarlyHintPreloader::AsyncOnChannelRedirect and
+  // EarlyHintPreloader::OnRedirectResult
+  mRedirectChannel = nullptr;
+  if (mChannel) {
+    if (mSuspended) {
+      mChannel->Resume();
+    }
+    mChannel->CancelWithReason(aStatus, aReason);
+    // Clearing mChannel is safe, because this EarlyHintPreloader is not in the
+    // EarlyHintRegistrar after this function call and we won't call
+    // SetHttpChannelFromEarlyHintPreloader nor OnStartRequest on mParent.
+    mChannel = nullptr;
+    SetState(ePreloaderCancelled);
+  }
+  return NS_OK;
+}
+
+void EarlyHintPreloader::OnParentReady(nsIParentChannel* aParent,
+                                       uint64_t aChannelId) {
+  AssertIsOnMainThread();
+  MOZ_ASSERT(aParent);
+  LOG(("EarlyHintPreloader::OnParentReady [this=%p]\n", this));
+
+  mParent = aParent;
+  mChannelId = aChannelId;
+
+  if (mTimer) {
+    mTimer->Cancel();
+    mTimer = nullptr;
+  }
+
+  RefPtr<EarlyHintRegistrar> registrar = EarlyHintRegistrar::GetOrCreate();
+  registrar->DeleteEntry(mConnectArgs.earlyHintPreloaderId());
+
+  if (mOnStartRequestCalled) {
+    SetParentChannel();
+    InvokeStreamListenerFunctions();
+  }
+}
+
+void EarlyHintPreloader::SetParentChannel() {
+  RefPtr<HttpBaseChannel> channel = do_QueryObject(mChannel);
+  RefPtr<HttpChannelParent> parent = do_QueryObject(mParent);
+  parent->SetHttpChannelFromEarlyHintPreloader(channel);
+}
+
+// Adapted from
+// https://searchfox.org/mozilla-central/rev/b4150d1c6fae0c51c522df2d2c939cf5ad331d4c/netwerk/ipc/DocumentLoadListener.cpp#1311
+void EarlyHintPreloader::InvokeStreamListenerFunctions() {
+  AssertIsOnMainThread();
+
+  LOG((
+      "EarlyHintPreloader::InvokeStreamListenerFunctions [this=%p parent=%p]\n",
+      this, mParent.get()));
+
+  if (nsCOMPtr<nsIIdentChannel> channel = do_QueryInterface(mChannel)) {
+    MOZ_ASSERT(mChannelId);
+    DebugOnly<nsresult> rv = channel->SetChannelId(mChannelId);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+  }
+
+  // If we failed to suspend the channel, then we might have received
+  // some messages while the redirected was being handled.
+  // Manually send them on now.
+  if (!mIsFinished) {
+    // This is safe to do, because OnStartRequest/OnStopRequest/OnDataAvailable
+    // are all called on the main thread. They can't be called until we worked
+    // through all functions in the streamListnerFunctions array.
+    mParentListener->SetListenerAfterRedirect(mParent);
+  }
+  nsTArray<StreamListenerFunction> streamListenerFunctions =
+      std::move(mStreamListenerFunctions);
+
+  ForwardStreamListenerFunctions(streamListenerFunctions, mParent);
+
+  // We don't expect to get new stream listener functions added
+  // via re-entrancy. If this ever happens, we should understand
+  // exactly why before allowing it.
+  NS_ASSERTION(mStreamListenerFunctions.IsEmpty(),
+               "Should not have added new stream listener function!");
+
+  if (mChannel && mSuspended) {
+    mChannel->Resume();
+  }
+  mChannel = nullptr;
+  mParent = nullptr;
+  mParentListener = nullptr;
+
+  SetState(ePreloaderUsed);
+}
+
+//-----------------------------------------------------------------------------
+// EarlyHintPreloader::nsISupports
+//-----------------------------------------------------------------------------
+
+NS_IMPL_ISUPPORTS(EarlyHintPreloader, nsIRequestObserver, nsIStreamListener,
+                  nsIChannelEventSink, nsIInterfaceRequestor,
+                  nsIRedirectResultListener, nsIMultiPartChannelListener,
+                  nsINamed, nsITimerCallback);
+
+//-----------------------------------------------------------------------------
+// EarlyHintPreloader::nsIStreamListener
+//-----------------------------------------------------------------------------
+
+// Implementation copied and adapted from DocumentLoadListener::OnStartRequest
+// https://searchfox.org/mozilla-central/rev/380fc5571b039fd453b45bbb64ed13146fe9b066/netwerk/ipc/DocumentLoadListener.cpp#2317-2508
+NS_IMETHODIMP
+EarlyHintPreloader::OnStartRequest(nsIRequest* aRequest) {
+  LOG(("EarlyHintPreloader::OnStartRequest [this=%p]\n", this));
+  AssertIsOnMainThread();
+
+  mOnStartRequestCalled = true;
+
+  nsCOMPtr<nsIMultiPartChannel> multiPartChannel = do_QueryInterface(aRequest);
+  if (multiPartChannel) {
+    multiPartChannel->GetBaseChannel(getter_AddRefs(mChannel));
+  } else {
+    mChannel = do_QueryInterface(aRequest);
+  }
+  MOZ_DIAGNOSTIC_ASSERT(mChannel);
+
+  nsresult status = NS_OK;
+  Unused << aRequest->GetStatus(&status);
+
+  if (mParent) {
+    SetParentChannel();
+    mParent->OnStartRequest(aRequest);
+    InvokeStreamListenerFunctions();
+  } else {
+    // Don't suspend the chanel when the channel got cancelled with
+    // CancelChannel, because then OnStopRequest wouldn't get called and we
+    // wouldn't clean up the channel.
+    if (NS_SUCCEEDED(status)) {
+      mChannel->Suspend();
+      mSuspended = true;
+    }
+    mStreamListenerFunctions.AppendElement(
+        AsVariant(OnStartRequestParams{aRequest}));
+  }
+
+  // return error after adding the OnStartRequest forward. The OnStartRequest
+  // failure has to be forwarded to listener, because they called AsyncOpen on
+  // this channel
+  return status;
+}
+
+// Implementation copied from DocumentLoadListener::OnStopRequest
+// https://searchfox.org/mozilla-central/rev/380fc5571b039fd453b45bbb64ed13146fe9b066/netwerk/ipc/DocumentLoadListener.cpp#2510-2528
+NS_IMETHODIMP
+EarlyHintPreloader::OnStopRequest(nsIRequest* aRequest, nsresult aStatusCode) {
+  AssertIsOnMainThread();
+  LOG(("EarlyHintPreloader::OnStopRequest [this=%p]\n", this));
+  mStreamListenerFunctions.AppendElement(
+      AsVariant(OnStopRequestParams{aRequest, aStatusCode}));
+
+  // If we're not a multi-part channel, then we're finished and we don't
+  // expect any further events. If we are, then this might be called again,
+  // so wait for OnAfterLastPart instead.
+  nsCOMPtr<nsIMultiPartChannel> multiPartChannel = do_QueryInterface(aRequest);
+  if (!multiPartChannel) {
+    mIsFinished = true;
+  }
+
+  return NS_OK;
+}
+
+//-----------------------------------------------------------------------------
+// EarlyHintPreloader::nsIStreamListener
+//-----------------------------------------------------------------------------
+
+// Implementation copied from DocumentLoadListener::OnDataAvailable
+// https://searchfox.org/mozilla-central/rev/380fc5571b039fd453b45bbb64ed13146fe9b066/netwerk/ipc/DocumentLoadListener.cpp#2530-2549
+NS_IMETHODIMP
+EarlyHintPreloader::OnDataAvailable(nsIRequest* aRequest,
+                                    nsIInputStream* aInputStream,
+                                    uint64_t aOffset, uint32_t aCount) {
+  AssertIsOnMainThread();
+  LOG(("EarlyHintPreloader::OnDataAvailable [this=%p]\n", this));
+  // This isn't supposed to happen, since we suspended the channel, but
+  // sometimes Suspend just doesn't work. This can happen when we're routing
+  // through nsUnknownDecoder to sniff the content type, and it doesn't handle
+  // being suspended. Let's just store the data and manually forward it to our
+  // redirected channel when it's ready.
+  nsCString data;
+  nsresult rv = NS_ReadInputStreamToString(aInputStream, data, aCount);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  mStreamListenerFunctions.AppendElement(
+      AsVariant(OnDataAvailableParams{aRequest, data, aOffset, aCount}));
+
+  return NS_OK;
+}
+
+//-----------------------------------------------------------------------------
+// EarlyHintPreloader::nsIMultiPartChannelListener
+//-----------------------------------------------------------------------------
+
+NS_IMETHODIMP
+EarlyHintPreloader::OnAfterLastPart(nsresult aStatus) {
+  LOG(("EarlyHintPreloader::OnAfterLastPart [this=%p]", this));
+  mStreamListenerFunctions.AppendElement(
+      AsVariant(OnAfterLastPartParams{aStatus}));
+  mIsFinished = true;
+  return NS_OK;
+}
+
+//-----------------------------------------------------------------------------
+// EarlyHintPreloader::nsIChannelEventSink
+//-----------------------------------------------------------------------------
+
+NS_IMETHODIMP
+EarlyHintPreloader::AsyncOnChannelRedirect(
+    nsIChannel* aOldChannel, nsIChannel* aNewChannel, uint32_t aFlags,
+    nsIAsyncVerifyRedirectCallback* callback) {
+  LOG(("EarlyHintPreloader::AsyncOnChannelRedirect [this=%p]", this));
+  nsCOMPtr<nsIURI> newURI;
+  nsresult rv = NS_GetFinalChannelURI(aNewChannel, getter_AddRefs(newURI));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = aNewChannel->GetURI(getter_AddRefs(newURI));
+  if (NS_FAILED(rv)) {
+    callback->OnRedirectVerifyCallback(rv);
+    return NS_OK;
+  }
+
+  // HTTP request headers are not automatically forwarded to the new channel.
+  nsCOMPtr<nsIHttpChannel> httpChannel = do_QueryInterface(aNewChannel);
+  NS_ENSURE_STATE(httpChannel);
+
+  rv = httpChannel->SetRequestHeader("X-Moz"_ns, "early hint"_ns, false);
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
+
+  // Assign to mChannel after we get notification about success of the
+  // redirect in OnRedirectResult.
+  mRedirectChannel = aNewChannel;
+
+  callback->OnRedirectVerifyCallback(NS_OK);
+  return NS_OK;
+}
+
+//-----------------------------------------------------------------------------
+// EarlyHintPreloader::nsIRedirectResultListener
+//-----------------------------------------------------------------------------
+
+NS_IMETHODIMP
+EarlyHintPreloader::OnRedirectResult(nsresult aStatus) {
+  LOG(("EarlyHintPreloader::OnRedirectResult [this=%p] aProceeding=0x%" PRIx32,
+       this, static_cast<uint32_t>(aStatus)));
+  if (NS_SUCCEEDED(aStatus) && mRedirectChannel) {
+    mChannel = mRedirectChannel;
+  }
+
+  mRedirectChannel = nullptr;
+
+  return NS_OK;
+}
+
+//-----------------------------------------------------------------------------
+// EarlyHintPreloader::nsINamed
+//-----------------------------------------------------------------------------
+
+NS_IMETHODIMP
+EarlyHintPreloader::GetName(nsACString& aName) {
+  aName.AssignLiteral("EarlyHintPreloader");
+  return NS_OK;
+}
+
+//-----------------------------------------------------------------------------
+// EarlyHintPreloader::nsITimerCallback
+//-----------------------------------------------------------------------------
+
+NS_IMETHODIMP
+EarlyHintPreloader::Notify(nsITimer* timer) {
+  // Death grip, because we will most likely remove the last reference when
+  // deleting us from the EarlyHintRegistrar
+  RefPtr<EarlyHintPreloader> deathGrip(this);
+
+  RefPtr<EarlyHintRegistrar> registrar = EarlyHintRegistrar::GetOrCreate();
+  registrar->DeleteEntry(mConnectArgs.earlyHintPreloaderId());
+
+  mTimer = nullptr;
+  mRedirectChannel = nullptr;
+  if (mChannel) {
+    if (mSuspended) {
+      mChannel->Resume();
+    }
+    mChannel->CancelWithReason(NS_ERROR_ABORT, "parent-connect-timeout"_ns);
+    mChannel = nullptr;
+  }
+  SetState(ePreloaderTimeout);
+
+  return NS_OK;
+}
+
+//-----------------------------------------------------------------------------
+// EarlyHintPreloader::nsIInterfaceRequestor
+//-----------------------------------------------------------------------------
+
+NS_IMETHODIMP
+EarlyHintPreloader::GetInterface(const nsIID& aIID, void** aResult) {
+  if (aIID.Equals(NS_GET_IID(nsIChannelEventSink))) {
+    NS_ADDREF_THIS();
+    *aResult = static_cast<nsIChannelEventSink*>(this);
+    return NS_OK;
+  }
+
+  if (aIID.Equals(NS_GET_IID(nsIRedirectResultListener))) {
+    NS_ADDREF_THIS();
+    *aResult = static_cast<nsIRedirectResultListener*>(this);
+    return NS_OK;
+  }
+
+  return NS_ERROR_NO_INTERFACE;
+}
+
+void EarlyHintPreloader::CollectResourcesTypeTelemetry(
+    ASDestination aASDestination) {
+  if (aASDestination == ASDestination::DESTINATION_FONT) {
+    glean::netwerk::early_hints.Get("font"_ns).Add(1);
+  } else if (aASDestination == ASDestination::DESTINATION_SCRIPT) {
+    glean::netwerk::early_hints.Get("script"_ns).Add(1);
+  } else if (aASDestination == ASDestination::DESTINATION_STYLE) {
+    glean::netwerk::early_hints.Get("stylesheet"_ns).Add(1);
+  } else if (aASDestination == ASDestination::DESTINATION_IMAGE) {
+    glean::netwerk::early_hints.Get("image"_ns).Add(1);
+  } else if (aASDestination == ASDestination::DESTINATION_FETCH) {
+    glean::netwerk::early_hints.Get("fetch"_ns).Add(1);
+  } else {
+    glean::netwerk::early_hints.Get("other"_ns).Add(1);
+  }
+}
+}  // namespace mozilla::net