dom/script/ScriptLoader.cpp
author Dorel Luca <dluca@mozilla.com>
Thu, 14 Mar 2019 09:14:15 +0200
changeset 521851 4d0c32fbf17c2146a1c1a51afc458de79c10b705
parent 521848 7e6a8fadff5ba02444e977b5dcaa8d479dfa3341
child 521918 d5c86748df920cdd1130279b2b9cd45a0e217f30
permissions -rw-r--r--
Backed out 5 changesets (bug 1533074) for eslint failure Backed out changeset 36c6a7178a5c (bug 1533074) Backed out changeset 7e6a8fadff5b (bug 1533074) Backed out changeset 2a0494fed543 (bug 1533074) Backed out changeset 38470d2dd98c (bug 1533074) Backed out changeset af4e03d1f5c8 (bug 1533074)

/* -*- 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 "ScriptLoader.h"
#include "ScriptLoadHandler.h"
#include "ScriptLoadRequest.h"
#include "ScriptTrace.h"
#include "LoadedScript.h"
#include "ModuleLoadRequest.h"

#include "prsystem.h"
#include "jsapi.h"
#include "jsfriendapi.h"
#include "js/CompilationAndEvaluation.h"
#include "js/MemoryFunctions.h"
#include "js/OffThreadScriptCompilation.h"
#include "js/Realm.h"
#include "js/SourceText.h"
#include "js/Utility.h"
#include "xpcpublic.h"
#include "nsCycleCollectionParticipant.h"
#include "nsIContent.h"
#include "nsJSUtils.h"
#include "mozilla/dom/DocGroup.h"
#include "mozilla/dom/Element.h"
#include "mozilla/dom/ScriptSettings.h"
#include "mozilla/dom/SRILogHelper.h"
#include "mozilla/net/UrlClassifierFeatureFactory.h"
#include "nsGkAtoms.h"
#include "nsNetUtil.h"
#include "nsGlobalWindowInner.h"
#include "nsIScriptGlobalObject.h"
#include "nsIScriptContext.h"
#include "nsIScriptSecurityManager.h"
#include "nsIPrincipal.h"
#include "nsJSPrincipals.h"
#include "nsContentPolicyUtils.h"
#include "nsIHttpChannel.h"
#include "nsIHttpChannelInternal.h"
#include "nsIClassOfService.h"
#include "nsICacheInfoChannel.h"
#include "nsITimedChannel.h"
#include "nsIScriptElement.h"
#include "nsIDocShell.h"
#include "nsContentUtils.h"
#include "nsUnicharUtils.h"
#include "nsAutoPtr.h"
#include "nsIXPConnect.h"
#include "nsError.h"
#include "nsThreadUtils.h"
#include "nsDocShellCID.h"
#include "nsIContentSecurityPolicy.h"
#include "mozilla/Logging.h"
#include "nsCRT.h"
#include "nsContentCreatorFunctions.h"
#include "nsProxyRelease.h"
#include "nsSandboxFlags.h"
#include "nsContentTypeParser.h"
#include "nsINetworkPredictor.h"
#include "nsMimeTypes.h"
#include "mozilla/ConsoleReportCollector.h"
#include "mozilla/LoadInfo.h"

#include "mozilla/AsyncEventDispatcher.h"
#include "mozilla/Attributes.h"
#include "mozilla/Telemetry.h"
#include "mozilla/TimeStamp.h"
#include "mozilla/Unused.h"
#include "nsIScriptError.h"
#include "nsIAsyncOutputStream.h"

using JS::SourceText;

using mozilla::Telemetry::LABELS_DOM_SCRIPT_PRELOAD_RESULT;

namespace mozilla {
namespace dom {

LazyLogModule ScriptLoader::gCspPRLog("CSP");
LazyLogModule ScriptLoader::gScriptLoaderLog("ScriptLoader");

#undef LOG
#define LOG(args) \
  MOZ_LOG(ScriptLoader::gScriptLoaderLog, mozilla::LogLevel::Debug, args)

#define LOG_ENABLED() \
  MOZ_LOG_TEST(ScriptLoader::gScriptLoaderLog, mozilla::LogLevel::Debug)

// Alternate Data MIME type used by the ScriptLoader to register that we want to
// store bytecode without reading it.
static NS_NAMED_LITERAL_CSTRING(kNullMimeType, "javascript/null");

//////////////////////////////////////////////////////////////
// ScriptLoader::PreloadInfo
//////////////////////////////////////////////////////////////

inline void ImplCycleCollectionUnlink(ScriptLoader::PreloadInfo& aField) {
  ImplCycleCollectionUnlink(aField.mRequest);
}

inline void ImplCycleCollectionTraverse(
    nsCycleCollectionTraversalCallback& aCallback,
    ScriptLoader::PreloadInfo& aField, const char* aName, uint32_t aFlags = 0) {
  ImplCycleCollectionTraverse(aCallback, aField.mRequest, aName, aFlags);
}

//////////////////////////////////////////////////////////////
// ScriptLoader
//////////////////////////////////////////////////////////////

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(ScriptLoader)
NS_INTERFACE_MAP_END

NS_IMPL_CYCLE_COLLECTION(ScriptLoader, mNonAsyncExternalScriptInsertedRequests,
                         mLoadingAsyncRequests, mLoadedAsyncRequests,
                         mDeferRequests, mXSLTRequests, mDynamicImportRequests,
                         mParserBlockingRequest, mBytecodeEncodingQueue,
                         mPreloads, mPendingChildLoaders, mFetchedModules)

NS_IMPL_CYCLE_COLLECTING_ADDREF(ScriptLoader)
NS_IMPL_CYCLE_COLLECTING_RELEASE(ScriptLoader)

ScriptLoader::ScriptLoader(Document* aDocument)
    : mDocument(aDocument),
      mParserBlockingBlockerCount(0),
      mBlockerCount(0),
      mNumberOfProcessors(0),
      mEnabled(true),
      mDeferEnabled(false),
      mDocumentParsingDone(false),
      mBlockingDOMContentLoaded(false),
      mLoadEventFired(false),
      mGiveUpEncoding(false),
      mReporter(new ConsoleReportCollector()) {
  LOG(("ScriptLoader::ScriptLoader %p", this));
  EnsureModuleHooksInitialized();
}

ScriptLoader::~ScriptLoader() {
  LOG(("ScriptLoader::~ScriptLoader %p", this));

  mObservers.Clear();

  if (mParserBlockingRequest) {
    mParserBlockingRequest->FireScriptAvailable(NS_ERROR_ABORT);
  }

  for (ScriptLoadRequest* req = mXSLTRequests.getFirst(); req;
       req = req->getNext()) {
    req->FireScriptAvailable(NS_ERROR_ABORT);
  }

  for (ScriptLoadRequest* req = mDeferRequests.getFirst(); req;
       req = req->getNext()) {
    req->FireScriptAvailable(NS_ERROR_ABORT);
  }

  for (ScriptLoadRequest* req = mLoadingAsyncRequests.getFirst(); req;
       req = req->getNext()) {
    req->FireScriptAvailable(NS_ERROR_ABORT);
  }

  for (ScriptLoadRequest* req = mLoadedAsyncRequests.getFirst(); req;
       req = req->getNext()) {
    req->FireScriptAvailable(NS_ERROR_ABORT);
  }

  for (ScriptLoadRequest* req = mDynamicImportRequests.getFirst(); req;
       req = req->getNext()) {
    FinishDynamicImport(req->AsModuleRequest(), NS_ERROR_ABORT);
  }

  for (ScriptLoadRequest* req =
           mNonAsyncExternalScriptInsertedRequests.getFirst();
       req; req = req->getNext()) {
    req->FireScriptAvailable(NS_ERROR_ABORT);
  }

  // Unblock the kids, in case any of them moved to a different document
  // subtree in the meantime and therefore aren't actually going away.
  for (uint32_t j = 0; j < mPendingChildLoaders.Length(); ++j) {
    mPendingChildLoaders[j]->RemoveParserBlockingScriptExecutionBlocker();
  }

  for (size_t i = 0; i < mPreloads.Length(); i++) {
    AccumulateCategorical(LABELS_DOM_SCRIPT_PRELOAD_RESULT::NotUsed);
  }
}

// Collect telemtry data about the cache information, and the kind of source
// which are being loaded, and where it is being loaded from.
static void CollectScriptTelemetry(ScriptLoadRequest* aRequest) {
  using namespace mozilla::Telemetry;

  // Skip this function if we are not running telemetry.
  if (!CanRecordExtended()) {
    return;
  }

  // Report the script kind.
  if (aRequest->IsModuleRequest()) {
    AccumulateCategorical(LABELS_DOM_SCRIPT_KIND::ModuleScript);
  } else {
    AccumulateCategorical(LABELS_DOM_SCRIPT_KIND::ClassicScript);
  }

  // Report the type of source. This is used to monitor the status of the
  // JavaScript Start-up Bytecode Cache, with the expectation of an almost zero
  // source-fallback and alternate-data being roughtly equal to source loads.
  if (aRequest->IsLoadingSource()) {
    if (aRequest->mIsInline) {
      AccumulateCategorical(LABELS_DOM_SCRIPT_LOADING_SOURCE::Inline);
    } else if (aRequest->IsTextSource()) {
      AccumulateCategorical(LABELS_DOM_SCRIPT_LOADING_SOURCE::SourceFallback);
    }
    // TODO: Add telemetry for BinAST encoded source.
  } else {
    MOZ_ASSERT(aRequest->IsLoading());
    if (aRequest->IsTextSource()) {
      AccumulateCategorical(LABELS_DOM_SCRIPT_LOADING_SOURCE::Source);
    } else if (aRequest->IsBytecode()) {
      AccumulateCategorical(LABELS_DOM_SCRIPT_LOADING_SOURCE::AltData);
    }
    // TODO: Add telemetry for BinAST encoded source.
  }
}

// Helper method for checking if the script element is an event-handler
// This means that it has both a for-attribute and a event-attribute.
// Also, if the for-attribute has a value that matches "\s*window\s*",
// and the event-attribute matches "\s*onload([ \(].*)?" then it isn't an
// eventhandler. (both matches are case insensitive).
// This is how IE seems to filter out a window's onload handler from a
// <script for=... event=...> element.

static bool IsScriptEventHandler(ScriptKind kind, nsIContent* aScriptElement) {
  if (kind != ScriptKind::eClassic) {
    return false;
  }

  if (!aScriptElement->IsHTMLElement()) {
    return false;
  }

  nsAutoString forAttr, eventAttr;
  if (!aScriptElement->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::_for,
                                            forAttr) ||
      !aScriptElement->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::event,
                                            eventAttr)) {
    return false;
  }

  const nsAString& for_str =
      nsContentUtils::TrimWhitespace<nsCRT::IsAsciiSpace>(forAttr);
  if (!for_str.LowerCaseEqualsLiteral("window")) {
    return true;
  }

  // We found for="window", now check for event="onload".
  const nsAString& event_str =
      nsContentUtils::TrimWhitespace<nsCRT::IsAsciiSpace>(eventAttr, false);
  if (!StringBeginsWith(event_str, NS_LITERAL_STRING("onload"),
                        nsCaseInsensitiveStringComparator())) {
    // It ain't "onload.*".

    return true;
  }

  nsAutoString::const_iterator start, end;
  event_str.BeginReading(start);
  event_str.EndReading(end);

  start.advance(6);  // advance past "onload"

  if (start != end && *start != '(' && *start != ' ') {
    // We got onload followed by something other than space or
    // '('. Not good enough.

    return true;
  }

  return false;
}

nsContentPolicyType ScriptLoadRequestToContentPolicyType(
    ScriptLoadRequest* aRequest) {
  if (aRequest->IsPreload()) {
    return aRequest->IsModuleRequest()
               ? nsIContentPolicy::TYPE_INTERNAL_MODULE_PRELOAD
               : nsIContentPolicy::TYPE_INTERNAL_SCRIPT_PRELOAD;
  }

  return aRequest->IsModuleRequest() ? nsIContentPolicy::TYPE_INTERNAL_MODULE
                                     : nsIContentPolicy::TYPE_INTERNAL_SCRIPT;
}

nsresult ScriptLoader::CheckContentPolicy(Document* aDocument,
                                          nsISupports* aContext,
                                          const nsAString& aType,
                                          ScriptLoadRequest* aRequest) {
  nsContentPolicyType contentPolicyType =
      ScriptLoadRequestToContentPolicyType(aRequest);

  nsCOMPtr<nsINode> requestingNode = do_QueryInterface(aContext);
  nsCOMPtr<nsILoadInfo> secCheckLoadInfo = new net::LoadInfo(
      aDocument->NodePrincipal(),  // loading principal
      aDocument->NodePrincipal(),  // triggering principal
      requestingNode, nsILoadInfo::SEC_ONLY_FOR_EXPLICIT_CONTENTSEC_CHECK,
      contentPolicyType);

  // snapshot the nonce at load start time for performing CSP checks
  if (contentPolicyType == nsIContentPolicy::TYPE_INTERNAL_SCRIPT ||
      contentPolicyType == nsIContentPolicy::TYPE_INTERNAL_MODULE) {
    nsCOMPtr<Element> element = do_QueryInterface(aContext);
    if (element && element->IsHTMLElement()) {
      nsAutoString cspNonce;
      element->GetAttribute(NS_LITERAL_STRING("nonce"), cspNonce);
      secCheckLoadInfo->SetCspNonce(cspNonce);
    }
  }

  int16_t shouldLoad = nsIContentPolicy::ACCEPT;
  nsresult rv = NS_CheckContentLoadPolicy(
      aRequest->mURI, secCheckLoadInfo, NS_LossyConvertUTF16toASCII(aType),
      &shouldLoad, nsContentUtils::GetContentPolicy());
  if (NS_FAILED(rv) || NS_CP_REJECTED(shouldLoad)) {
    if (NS_FAILED(rv) || shouldLoad != nsIContentPolicy::REJECT_TYPE) {
      return NS_ERROR_CONTENT_BLOCKED;
    }
    return NS_ERROR_CONTENT_BLOCKED_SHOW_ALT;
  }

  return NS_OK;
}

bool ScriptLoader::ModuleMapContainsURL(nsIURI* aURL) const {
  // Returns whether we have fetched, or are currently fetching, a module script
  // for a URL.
  return mFetchingModules.Contains(aURL) || mFetchedModules.Contains(aURL);
}

bool ScriptLoader::IsFetchingModule(ModuleLoadRequest* aRequest) const {
  bool fetching = mFetchingModules.Contains(aRequest->mURI);
  MOZ_ASSERT_IF(fetching, !mFetchedModules.Contains(aRequest->mURI));
  return fetching;
}

void ScriptLoader::SetModuleFetchStarted(ModuleLoadRequest* aRequest) {
  // Update the module map to indicate that a module is currently being fetched.

  MOZ_ASSERT(aRequest->IsLoading());
  MOZ_ASSERT(!ModuleMapContainsURL(aRequest->mURI));
  mFetchingModules.Put(aRequest->mURI, nullptr);
}

void ScriptLoader::SetModuleFetchFinishedAndResumeWaitingRequests(
    ModuleLoadRequest* aRequest, nsresult aResult) {
  // Update module map with the result of fetching a single module script.
  //
  // If any requests for the same URL are waiting on this one to complete, they
  // will have ModuleLoaded or LoadFailed on them when the promise is
  // resolved/rejected. This is set up in StartLoad.

  LOG(
      ("ScriptLoadRequest (%p): Module fetch finished (script == %p, result == "
       "%u)",
       aRequest, aRequest->mModuleScript.get(), unsigned(aResult)));

  RefPtr<GenericNonExclusivePromise::Private> promise;
  MOZ_ALWAYS_TRUE(
      mFetchingModules.Remove(aRequest->mURI, getter_AddRefs(promise)));

  RefPtr<ModuleScript> moduleScript(aRequest->mModuleScript);
  MOZ_ASSERT(NS_FAILED(aResult) == !moduleScript);

  mFetchedModules.Put(aRequest->mURI, moduleScript);

  if (promise) {
    if (moduleScript) {
      LOG(("ScriptLoadRequest (%p):   resolving %p", aRequest, promise.get()));
      promise->Resolve(true, __func__);
    } else {
      LOG(("ScriptLoadRequest (%p):   rejecting %p", aRequest, promise.get()));
      promise->Reject(aResult, __func__);
    }
  }
}

RefPtr<GenericNonExclusivePromise> ScriptLoader::WaitForModuleFetch(
    nsIURI* aURL) {
  MOZ_ASSERT(ModuleMapContainsURL(aURL));

  if (auto entry = mFetchingModules.Lookup(aURL)) {
    if (!entry.Data()) {
      entry.Data() = new GenericNonExclusivePromise::Private(__func__);
    }
    return entry.Data();
  }

  RefPtr<ModuleScript> ms;
  MOZ_ALWAYS_TRUE(mFetchedModules.Get(aURL, getter_AddRefs(ms)));
  if (!ms) {
    return GenericNonExclusivePromise::CreateAndReject(NS_ERROR_FAILURE,
                                                       __func__);
  }

  return GenericNonExclusivePromise::CreateAndResolve(true, __func__);
}

ModuleScript* ScriptLoader::GetFetchedModule(nsIURI* aURL) const {
  if (LOG_ENABLED()) {
    nsAutoCString url;
    aURL->GetAsciiSpec(url);
    LOG(("GetFetchedModule %s", url.get()));
  }

  bool found;
  ModuleScript* ms = mFetchedModules.GetWeak(aURL, &found);
  MOZ_ASSERT(found);
  return ms;
}

nsresult ScriptLoader::ProcessFetchedModuleSource(ModuleLoadRequest* aRequest) {
  MOZ_ASSERT(!aRequest->mModuleScript);

  nsresult rv = CreateModuleScript(aRequest);
  MOZ_ASSERT(NS_FAILED(rv) == !aRequest->mModuleScript);

  aRequest->ClearScriptSource();

  if (NS_FAILED(rv)) {
    aRequest->LoadFailed();
    return rv;
  }

  if (!aRequest->mIsInline) {
    SetModuleFetchFinishedAndResumeWaitingRequests(aRequest, rv);
  }

  if (!aRequest->mModuleScript->HasParseError()) {
    StartFetchingModuleDependencies(aRequest);
  }

  return NS_OK;
}

static nsresult ResolveRequestedModules(ModuleLoadRequest* aRequest,
                                        nsCOMArray<nsIURI>* aUrlsOut);

nsresult ScriptLoader::CreateModuleScript(ModuleLoadRequest* aRequest) {
  MOZ_ASSERT(!aRequest->mModuleScript);
  MOZ_ASSERT(aRequest->mBaseURL);

  LOG(("ScriptLoadRequest (%p): Create module script", aRequest));

  nsCOMPtr<nsIScriptGlobalObject> globalObject = GetScriptGlobalObject();
  if (!globalObject) {
    return NS_ERROR_FAILURE;
  }

  nsCOMPtr<nsIScriptContext> context = globalObject->GetScriptContext();
  if (!context) {
    return NS_ERROR_FAILURE;
  }

  nsAutoMicroTask mt;
  AutoEntryScript aes(globalObject, "CompileModule", true);

  bool oldProcessingScriptTag = context->GetProcessingScriptTag();
  context->SetProcessingScriptTag(true);

  nsresult rv;
  {
    JSContext* cx = aes.cx();
    JS::Rooted<JSObject*> module(cx);

    if (aRequest->mWasCompiledOMT) {
      module = JS::FinishOffThreadModule(cx, aRequest->mOffThreadToken);
      aRequest->mOffThreadToken = nullptr;
      rv = module ? NS_OK : NS_ERROR_FAILURE;
    } else {
      JS::Rooted<JSObject*> global(cx, globalObject->GetGlobalJSObject());

      JS::CompileOptions options(cx);
      rv = FillCompileOptionsForRequest(aes, aRequest, global, &options);

      if (NS_SUCCEEDED(rv)) {
        auto srcBuf = GetScriptSource(cx, aRequest);
        if (srcBuf) {
          rv = nsJSUtils::CompileModule(cx, *srcBuf, global, options, &module);
        } else {
          rv = NS_ERROR_OUT_OF_MEMORY;
        }
      }
    }

    MOZ_ASSERT(NS_SUCCEEDED(rv) == (module != nullptr));

    RefPtr<ModuleScript> moduleScript =
        new ModuleScript(aRequest->mFetchOptions, aRequest->mBaseURL);
    aRequest->mModuleScript = moduleScript;

    if (!module) {
      LOG(("ScriptLoadRequest (%p):   compilation failed (%d)", aRequest,
           unsigned(rv)));

      MOZ_ASSERT(aes.HasException());
      JS::Rooted<JS::Value> error(cx);
      if (!aes.StealException(&error)) {
        aRequest->mModuleScript = nullptr;
        return NS_ERROR_FAILURE;
      }

      moduleScript->SetParseError(error);
      aRequest->ModuleErrored();
      return NS_OK;
    }

    moduleScript->SetModuleRecord(module);

    // Validate requested modules and treat failure to resolve module specifiers
    // the same as a parse error.
    rv = ResolveRequestedModules(aRequest, nullptr);
    if (NS_FAILED(rv)) {
      aRequest->ModuleErrored();
      return NS_OK;
    }
  }

  context->SetProcessingScriptTag(oldProcessingScriptTag);

  LOG(("ScriptLoadRequest (%p):   module script == %p", aRequest,
       aRequest->mModuleScript.get()));

  return rv;
}

static nsresult HandleResolveFailure(JSContext* aCx, ModuleScript* aScript,
                                     const nsAString& aSpecifier,
                                     uint32_t aLineNumber,
                                     uint32_t aColumnNumber) {
  nsAutoCString url;
  aScript->BaseURL()->GetAsciiSpec(url);

  JS::Rooted<JSString*> filename(aCx);
  filename = JS_NewStringCopyZ(aCx, url.get());
  if (!filename) {
    return NS_ERROR_OUT_OF_MEMORY;
  }

  nsAutoString message(NS_LITERAL_STRING("Error resolving module specifier: "));
  message.Append(aSpecifier);

  JS::Rooted<JSString*> string(aCx, JS_NewUCStringCopyZ(aCx, message.get()));
  if (!string) {
    return NS_ERROR_OUT_OF_MEMORY;
  }

  JS::Rooted<JS::Value> error(aCx);
  if (!JS::CreateError(aCx, JSEXN_TYPEERR, nullptr, filename, aLineNumber,
                       aColumnNumber, nullptr, string, &error)) {
    return NS_ERROR_OUT_OF_MEMORY;
  }

  aScript->SetParseError(error);
  return NS_OK;
}

static already_AddRefed<nsIURI> ResolveModuleSpecifier(
    ScriptLoader* aLoader, LoadedScript* aScript, const nsAString& aSpecifier) {
  // The following module specifiers are allowed by the spec:
  //  - a valid absolute URL
  //  - a valid relative URL that starts with "/", "./" or "../"
  //
  // Bareword module specifiers are currently disallowed as these may be given
  // special meanings in the future.

  nsCOMPtr<nsIURI> uri;
  nsresult rv = NS_NewURI(getter_AddRefs(uri), aSpecifier);
  if (NS_SUCCEEDED(rv)) {
    return uri.forget();
  }

  if (rv != NS_ERROR_MALFORMED_URI) {
    return nullptr;
  }

  if (!StringBeginsWith(aSpecifier, NS_LITERAL_STRING("/")) &&
      !StringBeginsWith(aSpecifier, NS_LITERAL_STRING("./")) &&
      !StringBeginsWith(aSpecifier, NS_LITERAL_STRING("../"))) {
    return nullptr;
  }

  // Get the document's base URL if we don't have a referencing script here.
  nsCOMPtr<nsIURI> baseURL;
  if (aScript) {
    baseURL = aScript->BaseURL();
  } else {
    baseURL = aLoader->GetDocument()->GetDocBaseURI();
  }

  rv = NS_NewURI(getter_AddRefs(uri), aSpecifier, nullptr, baseURL);
  if (NS_SUCCEEDED(rv)) {
    return uri.forget();
  }

  return nullptr;
}

static nsresult ResolveRequestedModules(ModuleLoadRequest* aRequest,
                                        nsCOMArray<nsIURI>* aUrlsOut) {
  ModuleScript* ms = aRequest->mModuleScript;

  AutoJSAPI jsapi;
  if (!jsapi.Init(ms->ModuleRecord())) {
    return NS_ERROR_FAILURE;
  }

  JSContext* cx = jsapi.cx();
  JS::Rooted<JSObject*> moduleRecord(cx, ms->ModuleRecord());
  JS::Rooted<JSObject*> requestedModules(cx);
  requestedModules = JS::GetRequestedModules(cx, moduleRecord);
  MOZ_ASSERT(requestedModules);

  uint32_t length;
  if (!JS_GetArrayLength(cx, requestedModules, &length)) {
    return NS_ERROR_FAILURE;
  }

  JS::Rooted<JS::Value> element(cx);
  for (uint32_t i = 0; i < length; i++) {
    if (!JS_GetElement(cx, requestedModules, i, &element)) {
      return NS_ERROR_FAILURE;
    }

    JS::Rooted<JSString*> str(cx, JS::GetRequestedModuleSpecifier(cx, element));
    MOZ_ASSERT(str);

    nsAutoJSString specifier;
    if (!specifier.init(cx, str)) {
      return NS_ERROR_FAILURE;
    }

    // Let url be the result of resolving a module specifier given module script
    // and requested.
    nsCOMPtr<nsIURI> uri =
        ResolveModuleSpecifier(aRequest->mLoader, ms, specifier);
    if (!uri) {
      uint32_t lineNumber = 0;
      uint32_t columnNumber = 0;
      JS::GetRequestedModuleSourcePos(cx, element, &lineNumber, &columnNumber);

      nsresult rv =
          HandleResolveFailure(cx, ms, specifier, lineNumber, columnNumber);
      NS_ENSURE_SUCCESS(rv, rv);
      return NS_ERROR_FAILURE;
    }

    if (aUrlsOut) {
      aUrlsOut->AppendElement(uri.forget());
    }
  }

  return NS_OK;
}

void ScriptLoader::StartFetchingModuleDependencies(
    ModuleLoadRequest* aRequest) {
  LOG(("ScriptLoadRequest (%p): Start fetching module dependencies", aRequest));

  MOZ_ASSERT(aRequest->mModuleScript);
  MOZ_ASSERT(!aRequest->mModuleScript->HasParseError());
  MOZ_ASSERT(!aRequest->IsReadyToRun());

  auto visitedSet = aRequest->mVisitedSet;
  MOZ_ASSERT(visitedSet->Contains(aRequest->mURI));

  aRequest->mProgress = ModuleLoadRequest::Progress::eFetchingImports;

  nsCOMArray<nsIURI> urls;
  nsresult rv = ResolveRequestedModules(aRequest, &urls);
  if (NS_FAILED(rv)) {
    aRequest->ModuleErrored();
    return;
  }

  // Remove already visited URLs from the list. Put unvisited URLs into the
  // visited set.
  int32_t i = 0;
  while (i < urls.Count()) {
    nsIURI* url = urls[i];
    if (visitedSet->Contains(url)) {
      urls.RemoveObjectAt(i);
    } else {
      visitedSet->PutEntry(url);
      i++;
    }
  }

  if (urls.Count() == 0) {
    // There are no descendants to load so this request is ready.
    aRequest->DependenciesLoaded();
    return;
  }

  // For each url in urls, fetch a module script tree given url, module script's
  // CORS setting, and module script's settings object.
  nsTArray<RefPtr<GenericPromise>> importsReady;
  for (auto url : urls) {
    RefPtr<GenericPromise> childReady =
        StartFetchingModuleAndDependencies(aRequest, url);
    importsReady.AppendElement(childReady);
  }

  // Wait for all imports to become ready.
  RefPtr<GenericPromise::AllPromiseType> allReady =
      GenericPromise::All(GetMainThreadSerialEventTarget(), importsReady);
  allReady->Then(GetMainThreadSerialEventTarget(), __func__, aRequest,
                 &ModuleLoadRequest::DependenciesLoaded,
                 &ModuleLoadRequest::ModuleErrored);
}

RefPtr<GenericPromise> ScriptLoader::StartFetchingModuleAndDependencies(
    ModuleLoadRequest* aParent, nsIURI* aURI) {
  MOZ_ASSERT(aURI);

  RefPtr<ModuleLoadRequest> childRequest =
      ModuleLoadRequest::CreateStaticImport(aURI, aParent);

  aParent->mImports.AppendElement(childRequest);

  if (LOG_ENABLED()) {
    nsAutoCString url1;
    aParent->mURI->GetAsciiSpec(url1);

    nsAutoCString url2;
    aURI->GetAsciiSpec(url2);

    LOG(("ScriptLoadRequest (%p): Start fetching dependency %p", aParent,
         childRequest.get()));
    LOG(("StartFetchingModuleAndDependencies \"%s\" -> \"%s\"", url1.get(),
         url2.get()));
  }

  RefPtr<GenericPromise> ready = childRequest->mReady.Ensure(__func__);

  nsresult rv = StartLoad(childRequest);
  if (NS_FAILED(rv)) {
    MOZ_ASSERT(!childRequest->mModuleScript);
    LOG(("ScriptLoadRequest (%p):   rejecting %p", aParent,
         &childRequest->mReady));
    childRequest->mReady.Reject(rv, __func__);
    return ready;
  }

  return ready;
}

static ScriptLoader* GetCurrentScriptLoader(JSContext* aCx) {
  auto reportError = mozilla::MakeScopeExit([aCx]() {
    JS_ReportErrorASCII(aCx, "No ScriptLoader found for the current context");
  });

  JSObject* object = JS::CurrentGlobalOrNull(aCx);
  if (!object) {
    return nullptr;
  }

  nsIGlobalObject* global = xpc::NativeGlobal(object);
  if (!global) {
    return nullptr;
  }

  nsCOMPtr<nsPIDOMWindowInner> win = do_QueryInterface(global);
  nsGlobalWindowInner* innerWindow = nsGlobalWindowInner::Cast(win);
  if (!innerWindow) {
    return nullptr;
  }

  Document* document = innerWindow->GetDocument();
  if (!document) {
    return nullptr;
  }

  ScriptLoader* loader = document->ScriptLoader();
  if (!loader) {
    return nullptr;
  }

  reportError.release();
  return loader;
}

static LoadedScript* GetLoadedScriptOrNull(
    JSContext* aCx, JS::Handle<JS::Value> aReferencingPrivate) {
  if (aReferencingPrivate.isUndefined()) {
    return nullptr;
  }

  auto script = static_cast<LoadedScript*>(aReferencingPrivate.toPrivate());
  MOZ_ASSERT_IF(
      script->IsModuleScript(),
      JS::GetModulePrivate(script->AsModuleScript()->ModuleRecord()) ==
          aReferencingPrivate);

  return script;
}

// 8.1.3.8.1 HostResolveImportedModule(referencingModule, specifier)
JSObject* HostResolveImportedModule(JSContext* aCx,
                                    JS::Handle<JS::Value> aReferencingPrivate,
                                    JS::Handle<JSString*> aSpecifier) {
  JS::Rooted<JSObject*> module(aCx);
  ScriptLoader::ResolveImportedModule(aCx, aReferencingPrivate, aSpecifier,
                                      &module);
  return module;
}

/* static */
void ScriptLoader::ResolveImportedModule(
    JSContext* aCx, JS::Handle<JS::Value> aReferencingPrivate,
    JS::Handle<JSString*> aSpecifier, JS::MutableHandle<JSObject*> aModuleOut) {
  MOZ_ASSERT(!aModuleOut);

  RefPtr<LoadedScript> script(GetLoadedScriptOrNull(aCx, aReferencingPrivate));

  // Let url be the result of resolving a module specifier given referencing
  // module script and specifier.
  nsAutoJSString string;
  if (!string.init(aCx, aSpecifier)) {
    return;
  }

  RefPtr<ScriptLoader> loader = GetCurrentScriptLoader(aCx);
  if (!loader) {
    return;
  }

  nsCOMPtr<nsIURI> uri = ResolveModuleSpecifier(loader, script, string);

  // This cannot fail because resolving a module specifier must have been
  // previously successful with these same two arguments.
  MOZ_ASSERT(uri, "Failed to resolve previously-resolved module specifier");

  // Let resolved module script be moduleMap[url]. (This entry must exist for us
  // to have gotten to this point.)
  ModuleScript* ms = loader->GetFetchedModule(uri);
  MOZ_ASSERT(ms, "Resolved module not found in module map");
  MOZ_ASSERT(!ms->HasParseError());
  MOZ_ASSERT(ms->ModuleRecord());

  aModuleOut.set(ms->ModuleRecord());
}

bool HostPopulateImportMeta(JSContext* aCx,
                            JS::Handle<JS::Value> aReferencingPrivate,
                            JS::Handle<JSObject*> aMetaObject) {
  RefPtr<ModuleScript> script =
      static_cast<ModuleScript*>(aReferencingPrivate.toPrivate());
  MOZ_ASSERT(script->IsModuleScript());
  MOZ_ASSERT(JS::GetModulePrivate(script->ModuleRecord()) ==
             aReferencingPrivate);

  nsAutoCString url;
  MOZ_DIAGNOSTIC_ASSERT(script->BaseURL());
  MOZ_ALWAYS_SUCCEEDS(script->BaseURL()->GetAsciiSpec(url));

  JS::Rooted<JSString*> urlString(aCx, JS_NewStringCopyZ(aCx, url.get()));
  if (!urlString) {
    JS_ReportOutOfMemory(aCx);
    return false;
  }

  return JS_DefineProperty(aCx, aMetaObject, "url", urlString,
                           JSPROP_ENUMERATE);
}

bool HostImportModuleDynamically(JSContext* aCx,
                                 JS::Handle<JS::Value> aReferencingPrivate,
                                 JS::Handle<JSString*> aSpecifier,
                                 JS::Handle<JSObject*> aPromise) {
  RefPtr<LoadedScript> script(GetLoadedScriptOrNull(aCx, aReferencingPrivate));

  // Attempt to resolve the module specifier.
  nsAutoJSString string;
  if (!string.init(aCx, aSpecifier)) {
    return false;
  }

  RefPtr<ScriptLoader> loader = GetCurrentScriptLoader(aCx);
  if (!loader) {
    return false;
  }

  nsCOMPtr<nsIURI> uri = ResolveModuleSpecifier(loader, script, string);
  if (!uri) {
    JS_ReportErrorNumberUC(aCx, js::GetErrorMessage, nullptr,
                           JSMSG_BAD_MODULE_SPECIFIER, string.get());
    return false;
  }

  // Create a new top-level load request.
  ScriptFetchOptions* options;
  nsIURI* baseURL;
  if (script) {
    options = script->FetchOptions();
    baseURL = script->BaseURL();
  } else {
    // We don't have a referencing script so fall back on using
    // options from the document. This can happen when the user
    // triggers an inline event handler, as there is no active script
    // there.
    Document* document = loader->GetDocument();
    options = new ScriptFetchOptions(mozilla::CORS_NONE,
                                     document->GetReferrerPolicy(), nullptr,
                                     document->NodePrincipal());
    baseURL = document->GetDocBaseURI();
  }

  RefPtr<ModuleLoadRequest> request = ModuleLoadRequest::CreateDynamicImport(
      uri, options, baseURL, loader, aReferencingPrivate, aSpecifier, aPromise);

  loader->StartDynamicImport(request);
  return true;
}

void ScriptLoader::StartDynamicImport(ModuleLoadRequest* aRequest) {
  LOG(("ScriptLoadRequest (%p): Start dynamic import", aRequest));

  mDynamicImportRequests.AppendElement(aRequest);

  nsresult rv = StartLoad(aRequest);
  if (NS_FAILED(rv)) {
    FinishDynamicImport(aRequest, rv);
  }
}

void ScriptLoader::FinishDynamicImport(ModuleLoadRequest* aRequest,
                                       nsresult aResult) {
  AutoJSAPI jsapi;
  MOZ_ALWAYS_TRUE(jsapi.Init(aRequest->mDynamicPromise));
  FinishDynamicImport(jsapi.cx(), aRequest, aResult);
}

void ScriptLoader::FinishDynamicImport(JSContext* aCx,
                                       ModuleLoadRequest* aRequest,
                                       nsresult aResult) {
  LOG(("ScriptLoadRequest (%p): Finish dynamic import %x %d", aRequest,
       unsigned(aResult), JS_IsExceptionPending(aCx)));

  // Complete the dynamic import, report failures indicated by aResult or as a
  // pending exception on the context.

  if (NS_FAILED(aResult)) {
    MOZ_ASSERT(!JS_IsExceptionPending(aCx));
    JS_ReportErrorNumberUC(aCx, js::GetErrorMessage, nullptr,
                           JSMSG_DYNAMIC_IMPORT_FAILED);
  }

  JS::Rooted<JS::Value> referencingScript(aCx,
                                          aRequest->mDynamicReferencingPrivate);
  JS::Rooted<JSString*> specifier(aCx, aRequest->mDynamicSpecifier);
  JS::Rooted<JSObject*> promise(aCx, aRequest->mDynamicPromise);

  JS::FinishDynamicModuleImport(aCx, referencingScript, specifier, promise);

  // FinishDynamicModuleImport clears any pending exception.
  MOZ_ASSERT(!JS_IsExceptionPending(aCx));

  aRequest->ClearDynamicImport();
}

static void DynamicImportPrefChangedCallback(const char* aPrefName,
                                             void* aClosure) {
  bool enabled = Preferences::GetBool(aPrefName);
  JS::ModuleDynamicImportHook hook =
      enabled ? HostImportModuleDynamically : nullptr;

  AutoJSAPI jsapi;
  jsapi.Init();
  JSRuntime* rt = JS_GetRuntime(jsapi.cx());
  JS::SetModuleDynamicImportHook(rt, hook);
}

void ScriptLoader::EnsureModuleHooksInitialized() {
  AutoJSAPI jsapi;
  jsapi.Init();
  JSRuntime* rt = JS_GetRuntime(jsapi.cx());
  if (JS::GetModuleResolveHook(rt)) {
    return;
  }

  JS::SetModuleResolveHook(rt, HostResolveImportedModule);
  JS::SetModuleMetadataHook(rt, HostPopulateImportMeta);
  JS::SetScriptPrivateReferenceHooks(rt, HostAddRefTopLevelScript,
                                     HostReleaseTopLevelScript);

  Preferences::RegisterCallbackAndCall(DynamicImportPrefChangedCallback,
                                       "javascript.options.dynamicImport",
                                       (void*)nullptr);
}

void ScriptLoader::CheckModuleDependenciesLoaded(ModuleLoadRequest* aRequest) {
  LOG(("ScriptLoadRequest (%p): Check dependencies loaded", aRequest));

  RefPtr<ModuleScript> moduleScript = aRequest->mModuleScript;
  if (!moduleScript || moduleScript->HasParseError()) {
    return;
  }

  for (auto childRequest : aRequest->mImports) {
    ModuleScript* childScript = childRequest->mModuleScript;
    if (!childScript) {
      aRequest->mModuleScript = nullptr;
      LOG(("ScriptLoadRequest (%p):   %p failed (load error)", aRequest,
           childRequest.get()));
      return;
    }
  }

  LOG(("ScriptLoadRequest (%p):   all ok", aRequest));
}

class ScriptRequestProcessor : public Runnable {
 private:
  RefPtr<ScriptLoader> mLoader;
  RefPtr<ScriptLoadRequest> mRequest;

 public:
  ScriptRequestProcessor(ScriptLoader* aLoader, ScriptLoadRequest* aRequest)
      : Runnable("dom::ScriptRequestProcessor"),
        mLoader(aLoader),
        mRequest(aRequest) {}
  NS_IMETHOD Run() override {
    if (mRequest->IsModuleRequest() &&
        mRequest->AsModuleRequest()->IsDynamicImport()) {
      mLoader->ProcessDynamicImport(mRequest->AsModuleRequest());
      return NS_OK;
    }

    return mLoader->ProcessRequest(mRequest);
  }
};

void ScriptLoader::RunScriptWhenSafe(ScriptLoadRequest* aRequest) {
  auto runnable = new ScriptRequestProcessor(this, aRequest);
  nsContentUtils::AddScriptRunner(runnable);
}

void ScriptLoader::ProcessLoadedModuleTree(ModuleLoadRequest* aRequest) {
  MOZ_ASSERT(aRequest->IsReadyToRun());

  if (aRequest->IsTopLevel()) {
    if (aRequest->IsDynamicImport()) {
      MOZ_ASSERT(aRequest->isInList());
      RefPtr<ScriptLoadRequest> req = mDynamicImportRequests.Steal(aRequest);
      RunScriptWhenSafe(req);
    } else if (aRequest->mIsInline &&
               aRequest->GetParserCreated() == NOT_FROM_PARSER) {
      MOZ_ASSERT(!aRequest->isInList());
      RunScriptWhenSafe(aRequest);
    } else {
      MaybeMoveToLoadedList(aRequest);
      ProcessPendingRequests();
    }
  }

  if (aRequest->mWasCompiledOMT) {
    mDocument->UnblockOnload(false);
  }
}

JS::Value ScriptLoader::FindFirstParseError(ModuleLoadRequest* aRequest) {
  MOZ_ASSERT(aRequest);

  ModuleScript* moduleScript = aRequest->mModuleScript;
  MOZ_ASSERT(moduleScript);

  if (moduleScript->HasParseError()) {
    return moduleScript->ParseError();
  }

  for (ModuleLoadRequest* childRequest : aRequest->mImports) {
    JS::Value error = FindFirstParseError(childRequest);
    if (!error.isUndefined()) {
      return error;
    }
  }

  return JS::UndefinedValue();
}

bool ScriptLoader::InstantiateModuleTree(ModuleLoadRequest* aRequest) {
  // Instantiate a top-level module and record any error.

  MOZ_ASSERT(aRequest);
  MOZ_ASSERT(aRequest->IsTopLevel());

  LOG(("ScriptLoadRequest (%p): Instantiate module tree", aRequest));

  ModuleScript* moduleScript = aRequest->mModuleScript;
  MOZ_ASSERT(moduleScript);

  JS::Value parseError = FindFirstParseError(aRequest);
  if (!parseError.isUndefined()) {
    moduleScript->SetErrorToRethrow(parseError);
    LOG(("ScriptLoadRequest (%p):   found parse error", aRequest));
    return true;
  }

  MOZ_ASSERT(moduleScript->ModuleRecord());

  nsAutoMicroTask mt;
  AutoJSAPI jsapi;
  if (NS_WARN_IF(!jsapi.Init(moduleScript->ModuleRecord()))) {
    return false;
  }

  JS::Rooted<JSObject*> module(jsapi.cx(), moduleScript->ModuleRecord());
  bool ok = NS_SUCCEEDED(nsJSUtils::ModuleInstantiate(jsapi.cx(), module));

  if (!ok) {
    LOG(("ScriptLoadRequest (%p): Instantiate failed", aRequest));
    MOZ_ASSERT(jsapi.HasException());
    JS::RootedValue exception(jsapi.cx());
    if (!jsapi.StealException(&exception)) {
      return false;
    }
    MOZ_ASSERT(!exception.isUndefined());
    moduleScript->SetErrorToRethrow(exception);
  }

  return true;
}

nsresult ScriptLoader::InitDebuggerDataForModuleTree(
    JSContext* aCx, ModuleLoadRequest* aRequest) {
  // JS scripts can be associated with a DOM element for use by the debugger,
  // but preloading can cause scripts to be compiled before DOM script element
  // nodes have been created. This method ensures that this association takes
  // place before the first time a module script is run.

  MOZ_ASSERT(aRequest);

  ModuleScript* moduleScript = aRequest->mModuleScript;
  if (moduleScript->DebuggerDataInitialized()) {
    return NS_OK;
  }

  for (ModuleLoadRequest* childRequest : aRequest->mImports) {
    nsresult rv = InitDebuggerDataForModuleTree(aCx, childRequest);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  JS::Rooted<JSObject*> module(aCx, moduleScript->ModuleRecord());
  MOZ_ASSERT(module);

  nsIScriptElement* element = aRequest->Element();
  if (element) {
    nsresult rv = nsJSUtils::InitModuleSourceElement(aCx, module, element);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  // The script is now ready to be exposed to the debugger.
  JS::Rooted<JSScript*> script(aCx, JS::GetModuleScript(module));
  JS::ExposeScriptToDebugger(aCx, script);

  moduleScript->SetDebuggerDataInitialized();
  return NS_OK;
}

nsresult ScriptLoader::RestartLoad(ScriptLoadRequest* aRequest) {
  MOZ_ASSERT(aRequest->IsBytecode());
  aRequest->mScriptBytecode.clearAndFree();
  TRACE_FOR_TEST(aRequest->Element(), "scriptloader_fallback");

  // Start a new channel from which we explicitly request to stream the source
  // instead of the bytecode.
  aRequest->mProgress = ScriptLoadRequest::Progress::eLoading_Source;
  nsresult rv = StartLoad(aRequest);
  if (NS_FAILED(rv)) {
    return rv;
  }

  // Close the current channel and this ScriptLoadHandler as we created a new
  // one for the same request.
  return NS_BINDING_RETARGETED;
}

nsresult ScriptLoader::StartLoad(ScriptLoadRequest* aRequest) {
  MOZ_ASSERT(aRequest->IsLoading());
  NS_ENSURE_TRUE(mDocument, NS_ERROR_NULL_POINTER);
  aRequest->SetUnknownDataType();

  // If this document is sandboxed without 'allow-scripts', abort.
  if (mDocument->HasScriptsBlockedBySandbox()) {
    return NS_OK;
  }

  if (LOG_ENABLED()) {
    nsAutoCString url;
    aRequest->mURI->GetAsciiSpec(url);
    LOG(("ScriptLoadRequest (%p): Start Load (url = %s)", aRequest, url.get()));
  }

  if (aRequest->IsModuleRequest()) {
    // Check whether the module has been fetched or is currently being fetched,
    // and if so wait for it rather than starting a new fetch.
    ModuleLoadRequest* request = aRequest->AsModuleRequest();
    if (ModuleMapContainsURL(request->mURI)) {
      LOG(("ScriptLoadRequest (%p): Waiting for module fetch", aRequest));
      WaitForModuleFetch(request->mURI)
          ->Then(GetMainThreadSerialEventTarget(), __func__, request,
                 &ModuleLoadRequest::ModuleLoaded,
                 &ModuleLoadRequest::LoadFailed);
      return NS_OK;
    }
  }

  nsContentPolicyType contentPolicyType =
      ScriptLoadRequestToContentPolicyType(aRequest);
  nsCOMPtr<nsINode> context;
  if (aRequest->Element()) {
    context = do_QueryInterface(aRequest->Element());
  } else {
    context = mDocument;
  }

  nsCOMPtr<nsILoadGroup> loadGroup = mDocument->GetDocumentLoadGroup();
  nsCOMPtr<nsPIDOMWindowOuter> window = mDocument->GetWindow();
  NS_ENSURE_TRUE(window, NS_ERROR_NULL_POINTER);
  nsIDocShell* docshell = window->GetDocShell();
  nsCOMPtr<nsIInterfaceRequestor> prompter(do_QueryInterface(docshell));

  nsSecurityFlags securityFlags;
  if (aRequest->IsModuleRequest()) {
    // According to the spec, module scripts have different behaviour to classic
    // scripts and always use CORS.
    securityFlags = nsILoadInfo::SEC_REQUIRE_CORS_DATA_INHERITS;
    if (aRequest->CORSMode() == CORS_NONE ||
        aRequest->CORSMode() == CORS_ANONYMOUS) {
      securityFlags |= nsILoadInfo::SEC_COOKIES_SAME_ORIGIN;
    } else {
      MOZ_ASSERT(aRequest->CORSMode() == CORS_USE_CREDENTIALS);
      securityFlags |= nsILoadInfo::SEC_COOKIES_INCLUDE;
    }
  } else {
    securityFlags = aRequest->CORSMode() == CORS_NONE
                        ? nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_DATA_IS_NULL
                        : nsILoadInfo::SEC_REQUIRE_CORS_DATA_INHERITS;
    if (aRequest->CORSMode() == CORS_ANONYMOUS) {
      securityFlags |= nsILoadInfo::SEC_COOKIES_SAME_ORIGIN;
    } else if (aRequest->CORSMode() == CORS_USE_CREDENTIALS) {
      securityFlags |= nsILoadInfo::SEC_COOKIES_INCLUDE;
    }
  }
  securityFlags |= nsILoadInfo::SEC_ALLOW_CHROME;

  nsCOMPtr<nsIChannel> channel;
  nsresult rv = NS_NewChannelWithTriggeringPrincipal(
      getter_AddRefs(channel), aRequest->mURI, context,
      aRequest->TriggeringPrincipal(), securityFlags, contentPolicyType,
      nullptr,  // aPerformanceStorage
      loadGroup, prompter,
      nsIRequest::LOAD_NORMAL | nsIChannel::LOAD_CLASSIFY_URI);

  NS_ENSURE_SUCCESS(rv, rv);

  // snapshot the nonce at load start time for performing CSP checks
  if (contentPolicyType == nsIContentPolicy::TYPE_INTERNAL_SCRIPT ||
      contentPolicyType == nsIContentPolicy::TYPE_INTERNAL_MODULE) {
    nsCOMPtr<Element> element = do_QueryInterface(context);
    if (element && element->IsHTMLElement()) {
      nsAutoString cspNonce;
      element->GetAttribute(NS_LITERAL_STRING("nonce"), cspNonce);
      nsCOMPtr<nsILoadInfo> loadInfo = channel->LoadInfo();
      loadInfo->SetCspNonce(cspNonce);
    }
  }

  // To avoid decoding issues, the build-id is part of the JSBytecodeMimeType
  // constant.
  aRequest->mCacheInfo = nullptr;
  nsCOMPtr<nsICacheInfoChannel> cic(do_QueryInterface(channel));
  if (cic && nsContentUtils::IsBytecodeCacheEnabled() &&
      // Bug 1436400: no bytecode cache support for modules yet.
      !aRequest->IsModuleRequest()) {
    if (!aRequest->IsLoadingSource()) {
      // Inform the HTTP cache that we prefer to have information coming from
      // the bytecode cache instead of the sources, if such entry is already
      // registered.
      LOG(("ScriptLoadRequest (%p): Maybe request bytecode", aRequest));
      cic->PreferAlternativeDataType(nsContentUtils::JSBytecodeMimeType(),
                                     EmptyCString(), true);
    } else {
      // If we are explicitly loading from the sources, such as after a
      // restarted request, we might still want to save the bytecode after.
      //
      // The following tell the cache to look for an alternative data type which
      // does not exist, such that we can later save the bytecode with a
      // different alternative data type.
      LOG(("ScriptLoadRequest (%p): Request saving bytecode later", aRequest));
      cic->PreferAlternativeDataType(kNullMimeType, EmptyCString(), true);
    }
  }

  LOG(("ScriptLoadRequest (%p): mode=%u tracking=%d", aRequest,
       unsigned(aRequest->mScriptMode), aRequest->IsTracking()));

  nsCOMPtr<nsIClassOfService> cos(do_QueryInterface(channel));
  if (cos) {
    if (aRequest->mScriptFromHead && aRequest->IsBlockingScript()) {
      // synchronous head scripts block loading of most other non js/css
      // content such as images, Leader implicitely disallows tailing
      cos->AddClassFlags(nsIClassOfService::Leader);
    } else if (aRequest->IsDeferredScript() &&
               !nsContentUtils::IsTailingEnabled()) {
      // Bug 1395525 and the !nsContentUtils::IsTailingEnabled() bit:
      // We want to make sure that turing tailing off by the pref makes
      // the browser behave exactly the same way as before landing
      // the tailing patch.

      // head/body deferred scripts are blocked by leaders but are not
      // allowed tailing because they block DOMContentLoaded
      cos->AddClassFlags(nsIClassOfService::TailForbidden);
    } else {
      // other scripts (=body sync or head/body async) are neither blocked
      // nor prioritized
      cos->AddClassFlags(nsIClassOfService::Unblocked);

      if (aRequest->IsAsyncScript()) {
        // async scripts are allowed tailing, since those and only those
        // don't block DOMContentLoaded; this flag doesn't enforce tailing,
        // just overweights the Unblocked flag when the channel is found
        // to be a thrird-party tracker and thus set the Tail flag to engage
        // tailing.
        cos->AddClassFlags(nsIClassOfService::TailAllowed);
      }
    }
  }

  nsCOMPtr<nsIHttpChannel> httpChannel(do_QueryInterface(channel));
  if (httpChannel) {
    // HTTP content negotation has little value in this context.
    nsAutoCString acceptTypes("*/*");
    if (nsJSUtils::BinASTEncodingEnabled() &&
        aRequest->ShouldAcceptBinASTEncoding()) {
      acceptTypes = APPLICATION_JAVASCRIPT_BINAST ", */*";
    }
    rv = httpChannel->SetRequestHeader(NS_LITERAL_CSTRING("Accept"),
                                       acceptTypes, false);
    MOZ_ASSERT(NS_SUCCEEDED(rv));

    rv = httpChannel->SetReferrerWithPolicy(aRequest->mReferrer,
                                            aRequest->ReferrerPolicy());
    MOZ_ASSERT(NS_SUCCEEDED(rv));

    nsCOMPtr<nsIHttpChannelInternal> internalChannel(
        do_QueryInterface(httpChannel));
    if (internalChannel) {
      rv = internalChannel->SetIntegrityMetadata(
          aRequest->mIntegrity.GetIntegrityString());
      MOZ_ASSERT(NS_SUCCEEDED(rv));
    }
  }

  mozilla::net::PredictorLearn(
      aRequest->mURI, mDocument->GetDocumentURI(),
      nsINetworkPredictor::LEARN_LOAD_SUBRESOURCE,
      mDocument->NodePrincipal()->OriginAttributesRef());

  // Set the initiator type
  nsCOMPtr<nsITimedChannel> timedChannel(do_QueryInterface(httpChannel));
  if (timedChannel) {
    timedChannel->SetInitiatorType(NS_LITERAL_STRING("script"));
  }

  nsAutoPtr<mozilla::dom::SRICheckDataVerifier> sriDataVerifier;
  if (!aRequest->mIntegrity.IsEmpty()) {
    nsAutoCString sourceUri;
    if (mDocument->GetDocumentURI()) {
      mDocument->GetDocumentURI()->GetAsciiSpec(sourceUri);
    }
    sriDataVerifier =
        new SRICheckDataVerifier(aRequest->mIntegrity, sourceUri, mReporter);
  }

  RefPtr<ScriptLoadHandler> handler =
      new ScriptLoadHandler(this, aRequest, sriDataVerifier.forget());

  nsCOMPtr<nsIIncrementalStreamLoader> loader;
  rv = NS_NewIncrementalStreamLoader(getter_AddRefs(loader), handler);
  NS_ENSURE_SUCCESS(rv, rv);

  rv = channel->AsyncOpen(loader);
  NS_ENSURE_SUCCESS(rv, rv);

  if (aRequest->IsModuleRequest()) {
    // We successfully started fetching a module so put its URL in the module
    // map and mark it as fetching.
    SetModuleFetchStarted(aRequest->AsModuleRequest());
    LOG(("ScriptLoadRequest (%p): Start fetching module", aRequest));
  }

  return NS_OK;
}

bool ScriptLoader::PreloadURIComparator::Equals(const PreloadInfo& aPi,
                                                nsIURI* const& aURI) const {
  bool same;
  return NS_SUCCEEDED(aPi.mRequest->mURI->Equals(aURI, &same)) && same;
}

static bool CSPAllowsInlineScript(nsIScriptElement* aElement,
                                  Document* aDocument) {
  nsCOMPtr<nsIContentSecurityPolicy> csp;
  // Note: For imports NodePrincipal and the principal of the master are
  // the same.
  nsresult rv = aDocument->NodePrincipal()->GetCsp(getter_AddRefs(csp));
  NS_ENSURE_SUCCESS(rv, false);

  if (!csp) {
    // no CSP --> allow
    return true;
  }

  // query the nonce
  nsCOMPtr<Element> scriptContent = do_QueryInterface(aElement);
  nsAutoString nonce;
  scriptContent->GetAttr(kNameSpaceID_None, nsGkAtoms::nonce, nonce);
  bool parserCreated =
      aElement->GetParserCreated() != mozilla::dom::NOT_FROM_PARSER;

  bool allowInlineScript = false;
  rv = csp->GetAllowsInline(nsIContentPolicy::TYPE_SCRIPT, nonce, parserCreated,
                            scriptContent, nullptr /* nsICSPEventListener */,
                            EmptyString(), aElement->GetScriptLineNumber(),
                            aElement->GetScriptColumnNumber(),
                            &allowInlineScript);
  return allowInlineScript;
}

ScriptLoadRequest* ScriptLoader::CreateLoadRequest(
    ScriptKind aKind, nsIURI* aURI, nsIScriptElement* aElement,
    nsIPrincipal* aTriggeringPrincipal, CORSMode aCORSMode,
    const SRIMetadata& aIntegrity,
    mozilla::net::ReferrerPolicy aReferrerPolicy) {
  nsIURI* referrer = mDocument->GetDocumentURI();
  ScriptFetchOptions* fetchOptions = new ScriptFetchOptions(
      aCORSMode, aReferrerPolicy, aElement, aTriggeringPrincipal);

  if (aKind == ScriptKind::eClassic) {
    return new ScriptLoadRequest(aKind, aURI, fetchOptions, aIntegrity,
                                 referrer);
  }

  MOZ_ASSERT(aKind == ScriptKind::eModule);
  return ModuleLoadRequest::CreateTopLevel(aURI, fetchOptions, aIntegrity,
                                           referrer, this);
}

bool ScriptLoader::ProcessScriptElement(nsIScriptElement* aElement) {
  // We need a document to evaluate scripts.
  NS_ENSURE_TRUE(mDocument, false);

  // Check to see if scripts has been turned off.
  if (!mEnabled || !mDocument->IsScriptEnabled()) {
    return false;
  }

  NS_ASSERTION(!aElement->IsMalformed(), "Executing malformed script");

  nsCOMPtr<nsIContent> scriptContent = do_QueryInterface(aElement);

  nsAutoString type;
  bool hasType = aElement->GetScriptType(type);

  ScriptKind scriptKind = aElement->GetScriptIsModule() ? ScriptKind::eModule
                                                        : ScriptKind::eClassic;

  // Step 13. Check that the script is not an eventhandler
  if (IsScriptEventHandler(scriptKind, scriptContent)) {
    return false;
  }

  // For classic scripts, check the type attribute to determine language and
  // version. If type exists, it trumps the deprecated 'language='
  if (scriptKind == ScriptKind::eClassic) {
    if (!type.IsEmpty()) {
      NS_ENSURE_TRUE(nsContentUtils::IsJavascriptMIMEType(type), false);
    } else if (!hasType) {
      // no 'type=' element
      // "language" is a deprecated attribute of HTML, so we check it only for
      // HTML script elements.
      if (scriptContent->IsHTMLElement()) {
        nsAutoString language;
        scriptContent->AsElement()->GetAttr(kNameSpaceID_None,
                                            nsGkAtoms::language, language);
        if (!language.IsEmpty()) {
          if (!nsContentUtils::IsJavaScriptLanguage(language)) {
            return false;
          }
        }
      }
    }
  }

  // "In modern user agents that support module scripts, the script element with
  // the nomodule attribute will be ignored".
  // "The nomodule attribute must not be specified on module scripts (and will
  // be ignored if it is)."
  if (mDocument->ModuleScriptsEnabled() && scriptKind == ScriptKind::eClassic &&
      scriptContent->IsHTMLElement() &&
      scriptContent->AsElement()->HasAttr(kNameSpaceID_None,
                                          nsGkAtoms::nomodule)) {
    return false;
  }

  // Step 15. and later in the HTML5 spec
  if (aElement->GetScriptExternal()) {
    return ProcessExternalScript(aElement, scriptKind, type, scriptContent);
  }

  return ProcessInlineScript(aElement, scriptKind);
}

bool ScriptLoader::ProcessExternalScript(nsIScriptElement* aElement,
                                         ScriptKind aScriptKind,
                                         nsAutoString aTypeAttr,
                                         nsIContent* aScriptContent) {
  LOG(("ScriptLoader (%p): Process external script for element %p", this,
       aElement));

  nsCOMPtr<nsIURI> scriptURI = aElement->GetScriptURI();
  if (!scriptURI) {
    // Asynchronously report the failure to create a URI object
    NS_DispatchToCurrentThread(
        NewRunnableMethod("nsIScriptElement::FireErrorEvent", aElement,
                          &nsIScriptElement::FireErrorEvent));
    return false;
  }

  RefPtr<ScriptLoadRequest> request =
      LookupPreloadRequest(aElement, aScriptKind);

  if (request &&
      NS_FAILED(CheckContentPolicy(mDocument, aElement, aTypeAttr, request))) {
    LOG(("ScriptLoader (%p): content policy check failed for preload", this));

    // Probably plans have changed; even though the preload was allowed seems
    // like the actual load is not; let's cancel the preload request.
    request->Cancel();
    AccumulateCategorical(LABELS_DOM_SCRIPT_PRELOAD_RESULT::RejectedByPolicy);
    return false;
  }

  if (request) {
    // Use the preload request.

    LOG(("ScriptLoadRequest (%p): Using preload request", request.get()));

    // It's possible these attributes changed since we started the preload so
    // update them here.
    request->SetScriptMode(aElement->GetScriptDeferred(),
                           aElement->GetScriptAsync());

    AccumulateCategorical(LABELS_DOM_SCRIPT_PRELOAD_RESULT::Used);
  } else {
    // No usable preload found.

    SRIMetadata sriMetadata;
    {
      nsAutoString integrity;
      aScriptContent->AsElement()->GetAttr(kNameSpaceID_None,
                                           nsGkAtoms::integrity, integrity);
      GetSRIMetadata(integrity, &sriMetadata);
    }

    nsCOMPtr<nsIPrincipal> principal =
        aElement->GetScriptURITriggeringPrincipal();
    if (!principal) {
      principal = aScriptContent->NodePrincipal();
    }

    CORSMode ourCORSMode = aElement->GetCORSMode();
    mozilla::net::ReferrerPolicy referrerPolicy = GetReferrerPolicy(aElement);

    request = CreateLoadRequest(aScriptKind, scriptURI, aElement, principal,
                                ourCORSMode, sriMetadata, referrerPolicy);
    request->mIsInline = false;
    request->SetScriptMode(aElement->GetScriptDeferred(),
                           aElement->GetScriptAsync());
    // keep request->mScriptFromHead to false so we don't treat non preloaded
    // scripts as blockers for full page load. See bug 792438.

    LOG(("ScriptLoadRequest (%p): Created request for external script",
         request.get()));

    nsresult rv = StartLoad(request);
    if (NS_FAILED(rv)) {
      ReportErrorToConsole(request, rv);

      // Asynchronously report the load failure
      nsCOMPtr<nsIRunnable> runnable =
          NewRunnableMethod("nsIScriptElement::FireErrorEvent", aElement,
                            &nsIScriptElement::FireErrorEvent);
      if (mDocument) {
        mDocument->Dispatch(TaskCategory::Other, runnable.forget());
      } else {
        NS_DispatchToCurrentThread(runnable);
      }
      return false;
    }
  }

  // We should still be in loading stage of script unless we're loading a
  // module.
  NS_ASSERTION(!request->InCompilingStage() || request->IsModuleRequest(),
               "Request should not yet be in compiling stage.");

  if (request->IsAsyncScript()) {
    AddAsyncRequest(request);
    if (request->IsReadyToRun()) {
      // The script is available already. Run it ASAP when the event
      // loop gets a chance to spin.

      // KVKV TODO: Instead of processing immediately, try off-thread-parsing
      // it and only schedule a pending ProcessRequest if that fails.
      ProcessPendingRequestsAsync();
    }
    return false;
  }
  if (!aElement->GetParserCreated()) {
    // Violate the HTML5 spec in order to make LABjs and the "order" plug-in
    // for RequireJS work with their Gecko-sniffed code path. See
    // http://lists.w3.org/Archives/Public/public-html/2010Oct/0088.html
    request->mIsNonAsyncScriptInserted = true;
    mNonAsyncExternalScriptInsertedRequests.AppendElement(request);
    if (request->IsReadyToRun()) {
      // The script is available already. Run it ASAP when the event
      // loop gets a chance to spin.
      ProcessPendingRequestsAsync();
    }
    return false;
  }
  // we now have a parser-inserted request that may or may not be still
  // loading
  if (request->IsDeferredScript()) {
    // We don't want to run this yet.
    // If we come here, the script is a parser-created script and it has
    // the defer attribute but not the async attribute. Since a
    // a parser-inserted script is being run, we came here by the parser
    // running the script, which means the parser is still alive and the
    // parse is ongoing.
    NS_ASSERTION(mDocument->GetCurrentContentSink() ||
                     aElement->GetParserCreated() == FROM_PARSER_XSLT,
                 "Non-XSLT Defer script on a document without an active "
                 "parser; bug 592366.");
    AddDeferRequest(request);
    return false;
  }

  if (aElement->GetParserCreated() == FROM_PARSER_XSLT) {
    // Need to maintain order for XSLT-inserted scripts
    NS_ASSERTION(!mParserBlockingRequest,
                 "Parser-blocking scripts and XSLT scripts in the same doc!");
    request->mIsXSLT = true;
    mXSLTRequests.AppendElement(request);
    if (request->IsReadyToRun()) {
      // The script is available already. Run it ASAP when the event
      // loop gets a chance to spin.
      ProcessPendingRequestsAsync();
    }
    return true;
  }

  if (request->IsReadyToRun() && ReadyToExecuteParserBlockingScripts()) {
    // The request has already been loaded and there are no pending style
    // sheets. If the script comes from the network stream, cheat for
    // performance reasons and avoid a trip through the event loop.
    if (aElement->GetParserCreated() == FROM_PARSER_NETWORK) {
      return ProcessRequest(request) == NS_ERROR_HTMLPARSER_BLOCK;
    }
    // Otherwise, we've got a document.written script, make a trip through
    // the event loop to hide the preload effects from the scripts on the
    // Web page.
    NS_ASSERTION(!mParserBlockingRequest,
                 "There can be only one parser-blocking script at a time");
    NS_ASSERTION(mXSLTRequests.isEmpty(),
                 "Parser-blocking scripts and XSLT scripts in the same doc!");
    mParserBlockingRequest = request;
    ProcessPendingRequestsAsync();
    return true;
  }

  // The script hasn't loaded yet or there's a style sheet blocking it.
  // The script will be run when it loads or the style sheet loads.
  NS_ASSERTION(!mParserBlockingRequest,
               "There can be only one parser-blocking script at a time");
  NS_ASSERTION(mXSLTRequests.isEmpty(),
               "Parser-blocking scripts and XSLT scripts in the same doc!");
  mParserBlockingRequest = request;
  return true;
}

bool ScriptLoader::ProcessInlineScript(nsIScriptElement* aElement,
                                       ScriptKind aScriptKind) {
  // Is this document sandboxed without 'allow-scripts'?
  if (mDocument->HasScriptsBlockedBySandbox()) {
    return false;
  }

  // Does CSP allow this inline script to run?
  if (!CSPAllowsInlineScript(aElement, mDocument)) {
    return false;
  }

  // Inline classic scripts ignore their CORS mode and are always CORS_NONE.
  CORSMode corsMode = CORS_NONE;
  if (aScriptKind == ScriptKind::eModule) {
    corsMode = aElement->GetCORSMode();
  }

  mozilla::net::ReferrerPolicy referrerPolicy = GetReferrerPolicy(aElement);
  RefPtr<ScriptLoadRequest> request =
      CreateLoadRequest(aScriptKind, mDocument->GetDocumentURI(), aElement,
                        mDocument->NodePrincipal(), corsMode,
                        SRIMetadata(),  // SRI doesn't apply
                        referrerPolicy);
  request->mIsInline = true;
  request->mLineNo = aElement->GetScriptLineNumber();
  request->mProgress = ScriptLoadRequest::Progress::eLoading_Source;
  request->SetTextSource();
  TRACE_FOR_TEST_BOOL(request->Element(), "scriptloader_load_source");
  CollectScriptTelemetry(request);

  // Only the 'async' attribute is heeded on an inline module script and
  // inline classic scripts ignore both these attributes.
  MOZ_ASSERT(!aElement->GetScriptDeferred());
  MOZ_ASSERT_IF(!request->IsModuleRequest(), !aElement->GetScriptAsync());
  request->SetScriptMode(false, aElement->GetScriptAsync());

  LOG(("ScriptLoadRequest (%p): Created request for inline script",
       request.get()));

  request->mBaseURL = mDocument->GetDocBaseURI();

  if (request->IsModuleRequest()) {
    ModuleLoadRequest* modReq = request->AsModuleRequest();
    if (aElement->GetParserCreated() != NOT_FROM_PARSER) {
      if (aElement->GetScriptAsync()) {
        AddAsyncRequest(modReq);
      } else {
        AddDeferRequest(modReq);
      }
    }

    nsresult rv = ProcessFetchedModuleSource(modReq);
    if (NS_FAILED(rv)) {
      ReportErrorToConsole(modReq, rv);
      HandleLoadError(modReq, rv);
    }

    return false;
  }
  request->mProgress = ScriptLoadRequest::Progress::eReady;
  if (aElement->GetParserCreated() == FROM_PARSER_XSLT &&
      (!ReadyToExecuteParserBlockingScripts() || !mXSLTRequests.isEmpty())) {
    // Need to maintain order for XSLT-inserted scripts
    NS_ASSERTION(!mParserBlockingRequest,
                 "Parser-blocking scripts and XSLT scripts in the same doc!");
    mXSLTRequests.AppendElement(request);
    return true;
  }
  if (aElement->GetParserCreated() == NOT_FROM_PARSER) {
    NS_ASSERTION(
        !nsContentUtils::IsSafeToRunScript(),
        "A script-inserted script is inserted without an update batch?");
    RunScriptWhenSafe(request);
    return false;
  }
  if (aElement->GetParserCreated() == FROM_PARSER_NETWORK &&
      !ReadyToExecuteParserBlockingScripts()) {
    NS_ASSERTION(!mParserBlockingRequest,
                 "There can be only one parser-blocking script at a time");
    mParserBlockingRequest = request;
    NS_ASSERTION(mXSLTRequests.isEmpty(),
                 "Parser-blocking scripts and XSLT scripts in the same doc!");
    return true;
  }
  // We now have a document.written inline script or we have an inline script
  // from the network but there is no style sheet that is blocking scripts.
  // Don't check for style sheets blocking scripts in the document.write
  // case to avoid style sheet network activity affecting when
  // document.write returns. It's not really necessary to do this if
  // there's no document.write currently on the call stack. However,
  // this way matches IE more closely than checking if document.write
  // is on the call stack.
  NS_ASSERTION(nsContentUtils::IsSafeToRunScript(),
               "Not safe to run a parser-inserted script?");
  return ProcessRequest(request) == NS_ERROR_HTMLPARSER_BLOCK;
}

ScriptLoadRequest* ScriptLoader::LookupPreloadRequest(
    nsIScriptElement* aElement, ScriptKind aScriptKind) {
  MOZ_ASSERT(aElement);

  nsTArray<PreloadInfo>::index_type i =
      mPreloads.IndexOf(aElement->GetScriptURI(), 0, PreloadURIComparator());
  if (i == nsTArray<PreloadInfo>::NoIndex) {
    return nullptr;
  }

  // Found preloaded request. Note that a script-inserted script can steal a
  // preload!
  RefPtr<ScriptLoadRequest> request = mPreloads[i].mRequest;
  request->SetIsLoadRequest(aElement);
  nsString preloadCharset(mPreloads[i].mCharset);
  mPreloads.RemoveElementAt(i);

  // Double-check that the charset the preload used is the same as the charset
  // we have now.
  nsAutoString elementCharset;
  aElement->GetScriptCharset(elementCharset);
  mozilla::net::ReferrerPolicy referrerPolicy = GetReferrerPolicy(aElement);

  if (!elementCharset.Equals(preloadCharset) ||
      aElement->GetCORSMode() != request->CORSMode() ||
      referrerPolicy != request->ReferrerPolicy() ||
      aScriptKind != request->mKind) {
    // Drop the preload.
    request->Cancel();
    AccumulateCategorical(LABELS_DOM_SCRIPT_PRELOAD_RESULT::RequestMismatch);
    return nullptr;
  }

  // Report any errors that we skipped while preloading.
  ReportPreloadErrorsToConsole(request);

  return request;
}

void ScriptLoader::GetSRIMetadata(const nsAString& aIntegrityAttr,
                                  SRIMetadata* aMetadataOut) {
  MOZ_ASSERT(aMetadataOut->IsEmpty());

  if (aIntegrityAttr.IsEmpty()) {
    return;
  }

  MOZ_LOG(SRILogHelper::GetSriLog(), mozilla::LogLevel::Debug,
          ("ScriptLoader::GetSRIMetadata, integrity=%s",
           NS_ConvertUTF16toUTF8(aIntegrityAttr).get()));

  nsAutoCString sourceUri;
  if (mDocument->GetDocumentURI()) {
    mDocument->GetDocumentURI()->GetAsciiSpec(sourceUri);
  }
  SRICheck::IntegrityMetadata(aIntegrityAttr, sourceUri, mReporter,
                              aMetadataOut);
}

mozilla::net::ReferrerPolicy ScriptLoader::GetReferrerPolicy(
    nsIScriptElement* aElement) {
  mozilla::net::ReferrerPolicy scriptReferrerPolicy =
      aElement->GetReferrerPolicy();
  if (scriptReferrerPolicy != mozilla::net::RP_Unset) {
    return scriptReferrerPolicy;
  }
  return mDocument->GetReferrerPolicy();
}

namespace {

class NotifyOffThreadScriptLoadCompletedRunnable : public Runnable {
  RefPtr<ScriptLoadRequest> mRequest;
  RefPtr<ScriptLoader> mLoader;
  RefPtr<DocGroup> mDocGroup;
  JS::OffThreadToken* mToken;

 public:
  NotifyOffThreadScriptLoadCompletedRunnable(ScriptLoadRequest* aRequest,
                                             ScriptLoader* aLoader)
      : Runnable("dom::NotifyOffThreadScriptLoadCompletedRunnable"),
        mRequest(aRequest),
        mLoader(aLoader),
        mDocGroup(aLoader->GetDocGroup()),
        mToken(nullptr) {
    MOZ_ASSERT(NS_IsMainThread());
  }

  virtual ~NotifyOffThreadScriptLoadCompletedRunnable();

  void SetToken(JS::OffThreadToken* aToken) {
    MOZ_ASSERT(aToken && !mToken);
    mToken = aToken;
  }

  static void Dispatch(
      already_AddRefed<NotifyOffThreadScriptLoadCompletedRunnable>&& aSelf) {
    RefPtr<NotifyOffThreadScriptLoadCompletedRunnable> self = aSelf;
    RefPtr<DocGroup> docGroup = self->mDocGroup;
    docGroup->Dispatch(TaskCategory::Other, self.forget());
  }

  NS_DECL_NSIRUNNABLE
};

} /* anonymous namespace */

nsresult ScriptLoader::ProcessOffThreadRequest(ScriptLoadRequest* aRequest) {
  MOZ_ASSERT(aRequest->mProgress == ScriptLoadRequest::Progress::eCompiling);
  MOZ_ASSERT(!aRequest->mWasCompiledOMT);

  aRequest->mWasCompiledOMT = true;

  if (aRequest->IsModuleRequest()) {
    MOZ_ASSERT(aRequest->mOffThreadToken);
    ModuleLoadRequest* request = aRequest->AsModuleRequest();
    return ProcessFetchedModuleSource(request);
  }

  aRequest->SetReady();

  if (aRequest == mParserBlockingRequest) {
    if (!ReadyToExecuteParserBlockingScripts()) {
      // If not ready to execute scripts, schedule an async call to
      // ProcessPendingRequests to handle it.
      ProcessPendingRequestsAsync();
      return NS_OK;
    }

    // Same logic as in top of ProcessPendingRequests.
    mParserBlockingRequest = nullptr;
    UnblockParser(aRequest);
    ProcessRequest(aRequest);
    mDocument->UnblockOnload(false);
    ContinueParserAsync(aRequest);
    return NS_OK;
  }

  nsresult rv = ProcessRequest(aRequest);
  mDocument->UnblockOnload(false);
  return rv;
}

NotifyOffThreadScriptLoadCompletedRunnable::
    ~NotifyOffThreadScriptLoadCompletedRunnable() {
  if (MOZ_UNLIKELY(mRequest || mLoader) && !NS_IsMainThread()) {
    NS_ReleaseOnMainThreadSystemGroup(
        "NotifyOffThreadScriptLoadCompletedRunnable::mRequest",
        mRequest.forget());
    NS_ReleaseOnMainThreadSystemGroup(
        "NotifyOffThreadScriptLoadCompletedRunnable::mLoader",
        mLoader.forget());
  }
}

NS_IMETHODIMP
NotifyOffThreadScriptLoadCompletedRunnable::Run() {
  MOZ_ASSERT(NS_IsMainThread());

  // We want these to be dropped on the main thread, once we return from this
  // function.
  RefPtr<ScriptLoadRequest> request = mRequest.forget();
  RefPtr<ScriptLoader> loader = mLoader.forget();

  request->mOffThreadToken = mToken;
  nsresult rv = loader->ProcessOffThreadRequest(request);

  return rv;
}

static void OffThreadScriptLoaderCallback(JS::OffThreadToken* aToken,
                                          void* aCallbackData) {
  RefPtr<NotifyOffThreadScriptLoadCompletedRunnable> aRunnable = dont_AddRef(
      static_cast<NotifyOffThreadScriptLoadCompletedRunnable*>(aCallbackData));
  aRunnable->SetToken(aToken);
  NotifyOffThreadScriptLoadCompletedRunnable::Dispatch(aRunnable.forget());
}

nsresult ScriptLoader::AttemptAsyncScriptCompile(ScriptLoadRequest* aRequest,
                                                 bool* aCouldCompileOut) {
  MOZ_ASSERT_IF(!aRequest->IsModuleRequest(), aRequest->IsReadyToRun());
  MOZ_ASSERT(!aRequest->mWasCompiledOMT);
  MOZ_ASSERT(aCouldCompileOut && !*aCouldCompileOut);

  // Don't off-thread compile inline scripts.
  if (aRequest->mIsInline) {
    return NS_OK;
  }

  nsCOMPtr<nsIScriptGlobalObject> globalObject = GetScriptGlobalObject();
  if (!globalObject) {
    return NS_ERROR_FAILURE;
  }

  AutoJSAPI jsapi;
  if (!jsapi.Init(globalObject)) {
    return NS_ERROR_FAILURE;
  }

  JSContext* cx = jsapi.cx();
  JS::Rooted<JSObject*> global(cx, globalObject->GetGlobalJSObject());
  JS::CompileOptions options(cx);

  nsresult rv = FillCompileOptionsForRequest(jsapi, aRequest, global, &options);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  if (aRequest->IsTextSource()) {
    if (!JS::CanCompileOffThread(cx, options,
                                 aRequest->ScriptText().length())) {
      return NS_OK;
    }
#ifdef JS_BUILD_BINAST
  } else if (aRequest->IsBinASTSource()) {
    if (!JS::CanDecodeBinASTOffThread(cx, options,
                                      aRequest->ScriptBinASTData().length())) {
      return NS_OK;
    }
#endif
  } else {
    MOZ_ASSERT(aRequest->IsBytecode());
    size_t length =
        aRequest->mScriptBytecode.length() - aRequest->mBytecodeOffset;
    if (!JS::CanDecodeOffThread(cx, options, length)) {
      return NS_OK;
    }
  }

  RefPtr<NotifyOffThreadScriptLoadCompletedRunnable> runnable =
      new NotifyOffThreadScriptLoadCompletedRunnable(aRequest, this);

  if (aRequest->IsModuleRequest()) {
    MOZ_ASSERT(aRequest->IsTextSource());
    auto srcBuf = GetScriptSource(cx, aRequest);
    if (!srcBuf || !JS::CompileOffThreadModule(cx, options, *srcBuf,
                                               OffThreadScriptLoaderCallback,
                                               static_cast<void*>(runnable))) {
      return NS_ERROR_OUT_OF_MEMORY;
    }
  } else if (aRequest->IsBytecode()) {
    if (!JS::DecodeOffThreadScript(
            cx, options, aRequest->mScriptBytecode, aRequest->mBytecodeOffset,
            OffThreadScriptLoaderCallback, static_cast<void*>(runnable))) {
      return NS_ERROR_OUT_OF_MEMORY;
    }
#ifdef JS_BUILD_BINAST
  } else if (aRequest->IsBinASTSource()) {
    MOZ_ASSERT(aRequest->IsSource());
    if (!JS::DecodeBinASTOffThread(
            cx, options, aRequest->ScriptBinASTData().begin(),
            aRequest->ScriptBinASTData().length(),
            OffThreadScriptLoaderCallback, static_cast<void*>(runnable))) {
      return NS_ERROR_OUT_OF_MEMORY;
    }
#endif
  } else {
    MOZ_ASSERT(aRequest->IsTextSource());
    auto srcBuf = GetScriptSource(cx, aRequest);
    if (!srcBuf || !JS::CompileOffThread(cx, options, *srcBuf,
                                         OffThreadScriptLoaderCallback,
                                         static_cast<void*>(runnable))) {
      return NS_ERROR_OUT_OF_MEMORY;
    }
  }

  mDocument->BlockOnload();

  // Once the compilation is finished, an event would be added to the event loop
  // to call ScriptLoader::ProcessOffThreadRequest with the same request.
  aRequest->mProgress = ScriptLoadRequest::Progress::eCompiling;

  *aCouldCompileOut = true;
  Unused << runnable.forget();
  return NS_OK;
}

nsresult ScriptLoader::CompileOffThreadOrProcessRequest(
    ScriptLoadRequest* aRequest) {
  NS_ASSERTION(nsContentUtils::IsSafeToRunScript(),
               "Processing requests when running scripts is unsafe.");
  NS_ASSERTION(!aRequest->mOffThreadToken,
               "Candidate for off-thread compile is already parsed off-thread");
  NS_ASSERTION(
      !aRequest->InCompilingStage(),
      "Candidate for off-thread compile is already in compiling stage.");

  bool couldCompile = false;
  nsresult rv = AttemptAsyncScriptCompile(aRequest, &couldCompile);
  if (NS_FAILED(rv)) {
    HandleLoadError(aRequest, rv);
    return rv;
  }

  if (couldCompile) {
    return NS_OK;
  }

  return ProcessRequest(aRequest);
}

mozilla::Maybe<SourceText<char16_t>> ScriptLoader::GetScriptSource(
    JSContext* aCx, ScriptLoadRequest* aRequest) {
  // Return a SourceText<char16_t> object holding the script's source text.
  // Ownership of the buffer is transferred to the resulting holder.

  // If there's no script text, we try to get it from the element
  if (aRequest->mIsInline) {
    nsAutoString inlineData;
    aRequest->Element()->GetScriptText(inlineData);

    size_t nbytes = inlineData.Length() * sizeof(char16_t);
    JS::UniqueTwoByteChars chars(
        static_cast<char16_t*>(JS_malloc(aCx, nbytes)));
    if (!chars) {
      return Nothing();
    }

    memcpy(chars.get(), inlineData.get(), nbytes);

    SourceText<char16_t> srcBuf;
    if (!srcBuf.init(aCx, std::move(chars), inlineData.Length())) {
      return Nothing();
    }

    return Some(SourceText<char16_t>(std::move(srcBuf)));
  }

  size_t length = aRequest->ScriptText().length();
  JS::UniqueTwoByteChars chars(aRequest->ScriptText().extractOrCopyRawBuffer());
  if (!chars) {
    JS_ReportOutOfMemory(aCx);
    return Nothing();
  }

  SourceText<char16_t> srcBuf;
  if (!srcBuf.init(aCx, std::move(chars), length)) {
    return Nothing();
  }

  return Some(SourceText<char16_t>(std::move(srcBuf)));
}

nsresult ScriptLoader::ProcessRequest(ScriptLoadRequest* aRequest) {
  LOG(("ScriptLoadRequest (%p): Process request", aRequest));

  NS_ASSERTION(nsContentUtils::IsSafeToRunScript(),
               "Processing requests when running scripts is unsafe.");
  NS_ASSERTION(aRequest->IsReadyToRun(),
               "Processing a request that is not ready to run.");

  NS_ENSURE_ARG(aRequest);

  if (aRequest->IsModuleRequest()) {
    ModuleLoadRequest* request = aRequest->AsModuleRequest();
    if (request->mModuleScript) {
      if (!InstantiateModuleTree(request)) {
        request->mModuleScript = nullptr;
      }
    }

    if (!request->mModuleScript) {
      // There was an error fetching a module script.  Nothing to do here.
      LOG(("ScriptLoadRequest (%p):   Error loading request, firing error",
           aRequest));
      FireScriptAvailable(NS_ERROR_FAILURE, aRequest);
      return NS_OK;
    }
  }

  nsCOMPtr<nsINode> scriptElem = do_QueryInterface(aRequest->Element());

  nsCOMPtr<Document> doc;
  if (!aRequest->mIsInline) {
    doc = scriptElem->OwnerDoc();
  }

  nsCOMPtr<nsIScriptElement> oldParserInsertedScript;
  uint32_t parserCreated = aRequest->GetParserCreated();
  if (parserCreated) {
    oldParserInsertedScript = mCurrentParserInsertedScript;
    mCurrentParserInsertedScript = aRequest->Element();
  }

  aRequest->Element()->BeginEvaluating();

  FireScriptAvailable(NS_OK, aRequest);

  // The window may have gone away by this point, in which case there's no point
  // in trying to run the script.

  {
    // Try to perform a microtask checkpoint
    nsAutoMicroTask mt;
  }

  nsPIDOMWindowInner* pwin = mDocument->GetInnerWindow();
  bool runScript = !!pwin;
  if (runScript) {
    nsContentUtils::DispatchTrustedEvent(
        scriptElem->OwnerDoc(), scriptElem,
        NS_LITERAL_STRING("beforescriptexecute"), CanBubble::eYes,
        Cancelable::eYes, &runScript);
  }

  // Inner window could have gone away after firing beforescriptexecute
  pwin = mDocument->GetInnerWindow();
  if (!pwin) {
    runScript = false;
  }

  nsresult rv = NS_OK;
  if (runScript) {
    if (doc) {
      doc->IncrementIgnoreDestructiveWritesCounter();
    }
    rv = EvaluateScript(aRequest);
    if (doc) {
      doc->DecrementIgnoreDestructiveWritesCounter();
    }

    nsContentUtils::DispatchTrustedEvent(
        scriptElem->OwnerDoc(), scriptElem,
        NS_LITERAL_STRING("afterscriptexecute"), CanBubble::eYes,
        Cancelable::eNo);
  }

  FireScriptEvaluated(rv, aRequest);

  aRequest->Element()->EndEvaluating();

  if (parserCreated) {
    mCurrentParserInsertedScript = oldParserInsertedScript;
  }

  if (aRequest->mOffThreadToken) {
    // The request was parsed off-main-thread, but the result of the off
    // thread parse was not actually needed to process the request
    // (disappearing window, some other error, ...). Finish the
    // request to avoid leaks in the JS engine.
    MOZ_ASSERT(!aRequest->IsModuleRequest());
    aRequest->MaybeCancelOffThreadScript();
  }

  // Free any source data, but keep the bytecode content as we might have to
  // save it later.
  aRequest->ClearScriptSource();
  if (aRequest->IsBytecode()) {
    // We received bytecode as input, thus we were decoding, and we will not be
    // encoding the bytecode once more. We can safely clear the content of this
    // buffer.
    aRequest->mScriptBytecode.clearAndFree();
  }

  return rv;
}

void ScriptLoader::ProcessDynamicImport(ModuleLoadRequest* aRequest) {
  if (aRequest->mModuleScript) {
    if (!InstantiateModuleTree(aRequest)) {
      aRequest->mModuleScript = nullptr;
    }
  }

  nsresult rv = NS_ERROR_FAILURE;
  if (aRequest->mModuleScript) {
    rv = EvaluateScript(aRequest);
  }

  if (NS_FAILED(rv)) {
    FinishDynamicImport(aRequest, rv);
  }

  return;
}

void ScriptLoader::FireScriptAvailable(nsresult aResult,
                                       ScriptLoadRequest* aRequest) {
  for (int32_t i = 0; i < mObservers.Count(); i++) {
    nsCOMPtr<nsIScriptLoaderObserver> obs = mObservers[i];
    obs->ScriptAvailable(aResult, aRequest->Element(), aRequest->mIsInline,
                         aRequest->mURI, aRequest->mLineNo);
  }

  aRequest->FireScriptAvailable(aResult);
}

void ScriptLoader::FireScriptEvaluated(nsresult aResult,
                                       ScriptLoadRequest* aRequest) {
  for (int32_t i = 0; i < mObservers.Count(); i++) {
    nsCOMPtr<nsIScriptLoaderObserver> obs = mObservers[i];
    obs->ScriptEvaluated(aResult, aRequest->Element(), aRequest->mIsInline);
  }

  aRequest->FireScriptEvaluated(aResult);
}

already_AddRefed<nsIScriptGlobalObject> ScriptLoader::GetScriptGlobalObject() {
  if (!mDocument) {
    return nullptr;
  }

  nsPIDOMWindowInner* pwin = mDocument->GetInnerWindow();
  if (!pwin) {
    return nullptr;
  }

  nsCOMPtr<nsIScriptGlobalObject> globalObject = do_QueryInterface(pwin);
  NS_ASSERTION(globalObject, "windows must be global objects");

  // and make sure we are setup for this type of script.
  nsresult rv = globalObject->EnsureScriptEnvironment();
  if (NS_FAILED(rv)) {
    return nullptr;
  }

  return globalObject.forget();
}

nsresult ScriptLoader::FillCompileOptionsForRequest(
    const mozilla::dom::AutoJSAPI& jsapi, ScriptLoadRequest* aRequest,
    JS::Handle<JSObject*> aScopeChain, JS::CompileOptions* aOptions) {
  // It's very important to use aRequest->mURI, not the final URI of the channel
  // aRequest ended up getting script data from, as the script filename.
  nsresult rv = aRequest->mURI->GetSpec(aRequest->mURL);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  if (mDocument) {
    mDocument->NoteScriptTrackingStatus(aRequest->mURL, aRequest->IsTracking());
  }

  bool isScriptElement =
      !aRequest->IsModuleRequest() || aRequest->AsModuleRequest()->IsTopLevel();
  aOptions->setIntroductionInfoToCaller(
      jsapi.cx(), isScriptElement ? "scriptElement" : "importedModule");
  aOptions->setFileAndLine(aRequest->mURL.get(), aRequest->mLineNo);
  aOptions->setIsRunOnce(true);
  aOptions->setNoScriptRval(true);
  if (aRequest->mHasSourceMapURL) {
    aOptions->setSourceMapURL(aRequest->mSourceMapURL.get());
  }
  if (aRequest->mOriginPrincipal) {
    nsIPrincipal* scriptPrin = nsContentUtils::ObjectPrincipal(aScopeChain);
    bool subsumes = scriptPrin->Subsumes(aRequest->mOriginPrincipal);
    aOptions->setMutedErrors(!subsumes);
  }

  if (aRequest->IsModuleRequest()) {
    aOptions->hideScriptFromDebugger = true;
  } else {
    JSContext* cx = jsapi.cx();
    JS::Rooted<JS::Value> elementVal(cx);
    MOZ_ASSERT(aRequest->Element());
    if (NS_SUCCEEDED(nsContentUtils::WrapNative(cx, aRequest->Element(),
                                                &elementVal,
                                                /* aAllowWrapping = */ true))) {
      MOZ_ASSERT(elementVal.isObject());
      aOptions->setElement(&elementVal.toObject());
    }
  }

  return NS_OK;
}

/* static */
bool ScriptLoader::ShouldCacheBytecode(ScriptLoadRequest* aRequest) {
  using mozilla::TimeDuration;
  using mozilla::TimeStamp;

  // We need the nsICacheInfoChannel to exist to be able to open the alternate
  // data output stream. This pointer would only be non-null if the bytecode was
  // activated at the time the channel got created in StartLoad.
  if (!aRequest->mCacheInfo) {
    LOG(("ScriptLoadRequest (%p): Cannot cache anything (cacheInfo = %p)",
         aRequest, aRequest->mCacheInfo.get()));
    return false;
  }

  // Look at the preference to know which strategy (parameters) should be used
  // when the bytecode cache is enabled.
  int32_t strategy = nsContentUtils::BytecodeCacheStrategy();

  // List of parameters used by the strategies.
  bool hasSourceLengthMin = false;
  bool hasFetchCountMin = false;
  size_t sourceLengthMin = 100;
  size_t binASTLengthMin = 70;
  int32_t fetchCountMin = 4;

  LOG(("ScriptLoadRequest (%p): Bytecode-cache: strategy = %d.", aRequest,
       strategy));
  switch (strategy) {
    case -2: {
      // Reader mode, keep requesting alternate data but no longer save it.
      LOG(("ScriptLoadRequest (%p): Bytecode-cache: Encoding disabled.",
           aRequest));
      return false;
    }
    case -1: {
      // Eager mode, skip heuristics!
      hasSourceLengthMin = false;
      hasFetchCountMin = false;
      break;
    }
    default:
    case 0: {
      hasSourceLengthMin = true;
      hasFetchCountMin = true;
      sourceLengthMin = 1024;
      binASTLengthMin = 700;
      // If we were to optimize only for speed, without considering the impact
      // on memory, we should set this threshold to 2. (Bug 900784 comment 120)
      fetchCountMin = 4;
      break;
    }
  }

  // If the script is too small/large, do not attempt at creating a bytecode
  // cache for this script, as the overhead of parsing it might not be worth the
  // effort.
  if (hasSourceLengthMin) {
    size_t sourceLength;
    size_t minLength;
    if (aRequest->IsTextSource()) {
      sourceLength = aRequest->mScriptTextLength;
      minLength = sourceLengthMin;
    } else {
      MOZ_ASSERT(aRequest->IsBinASTSource());
      sourceLength = aRequest->ScriptBinASTData().length();
      minLength = binASTLengthMin;
    }
    if (sourceLength < minLength) {
      LOG(("ScriptLoadRequest (%p): Bytecode-cache: Script is too small.",
           aRequest));
      return false;
    }
  }

  // Check that we loaded the cache entry a few times before attempting any
  // bytecode-cache optimization, such that we do not waste time on entry which
  // are going to be dropped soon.
  if (hasFetchCountMin) {
    int32_t fetchCount = 0;
    if (NS_FAILED(aRequest->mCacheInfo->GetCacheTokenFetchCount(&fetchCount))) {
      LOG(("ScriptLoadRequest (%p): Bytecode-cache: Cannot get fetchCount.",
           aRequest));
      return false;
    }
    LOG(("ScriptLoadRequest (%p): Bytecode-cache: fetchCount = %d.", aRequest,
         fetchCount));
    if (fetchCount < fetchCountMin) {
      return false;
    }
  }

  LOG(("ScriptLoadRequest (%p): Bytecode-cache: Trigger encoding.", aRequest));
  return true;
}

class MOZ_RAII AutoSetProcessingScriptTag {
  nsCOMPtr<nsIScriptContext> mContext;
  bool mOldTag;

 public:
  explicit AutoSetProcessingScriptTag(nsIScriptContext* aContext)
      : mContext(aContext), mOldTag(mContext->GetProcessingScriptTag()) {
    mContext->SetProcessingScriptTag(true);
  }

  ~AutoSetProcessingScriptTag() { mContext->SetProcessingScriptTag(mOldTag); }
};

static nsresult ExecuteCompiledScript(JSContext* aCx,
                                      ScriptLoadRequest* aRequest,
                                      nsJSUtils::ExecutionContext& aExec) {
  JS::Rooted<JSScript*> script(aCx, aExec.MaybeGetScript());
  if (!script) {
    // Compilation succeeds without producing a script if scripting is
    // disabled for the global.
    return NS_OK;
  }

  // Create a ClassicScript object and associate it with the JSScript.
  RefPtr<ClassicScript> classicScript =
      new ClassicScript(aRequest->mFetchOptions, aRequest->mBaseURL);
  classicScript->AssociateWithScript(script);

  return aExec.ExecScript();
}

static void GetProfilerLabelForRequest(ScriptLoadRequest* aRequest,
                                       nsACString& aOutString) {
#ifdef MOZ_GECKO_PROFILER
  if (!profiler_is_active()) {
    aOutString.Append("<script> element");
    return;
  }
  aOutString.Append("<script");
  if (aRequest->IsAsyncScript()) {
    aOutString.Append(" async");
  } else if (aRequest->IsDeferredScript()) {
    aOutString.Append(" defer");
  }
  if (aRequest->IsModuleRequest()) {
    aOutString.Append(" type=\"module\"");
  }

  nsAutoCString url;
  if (aRequest->mURI) {
    aRequest->mURI->GetAsciiSpec(url);
  } else {
    url = "<unknown>";
  }

  if (aRequest->mIsInline) {
    if (aRequest->GetParserCreated() != NOT_FROM_PARSER) {
      aOutString.Append("> inline at line ");
      aOutString.AppendInt(aRequest->mLineNo);
      aOutString.Append(" of ");
    } else {
      aOutString.Append("> inline (dynamically created) in ");
    }
    aOutString.Append(url);
  } else {
    aOutString.Append(" src=\"");
    aOutString.Append(url);
    aOutString.Append("\">");
  }
#else
  aOutString.Append("<script> element");
#endif
}

nsresult ScriptLoader::EvaluateScript(ScriptLoadRequest* aRequest) {
  using namespace mozilla::Telemetry;
  MOZ_ASSERT(aRequest->IsReadyToRun());

  // We need a document to evaluate scripts.
  if (!mDocument) {
    return NS_ERROR_FAILURE;
  }

  bool isDynamicImport = aRequest->IsModuleRequest() &&
                         aRequest->AsModuleRequest()->IsDynamicImport();
  if (!isDynamicImport) {
    nsCOMPtr<nsIContent> scriptContent(do_QueryInterface(aRequest->Element()));
    MOZ_ASSERT(scriptContent);
    Document* ownerDoc = scriptContent->OwnerDoc();
    if (ownerDoc != mDocument) {
      // Willful violation of HTML5 as of 2010-12-01
      return NS_ERROR_FAILURE;
    }
  }

  nsCOMPtr<nsIScriptGlobalObject> globalObject = GetScriptGlobalObject();
  if (!globalObject) {
    return NS_ERROR_FAILURE;
  }

  // Make sure context is a strong reference since we access it after
  // we've executed a script, which may cause all other references to
  // the context to go away.
  nsCOMPtr<nsIScriptContext> context = globalObject->GetScriptContext();
  if (!context) {
    return NS_ERROR_FAILURE;
  }

  nsCOMPtr<nsPIDOMWindowOuter> window = mDocument->GetWindow();
#ifdef MOZ_GECKO_PROFILER
  nsIDocShell* docShell = window ? window->GetDocShell() : nullptr;
#endif
  nsAutoCString profilerLabelString;
  GetProfilerLabelForRequest(aRequest, profilerLabelString);
  AUTO_PROFILER_TEXT_MARKER_DOCSHELL("Script", profilerLabelString, JS,
                                     docShell);

  // New script entry point required, due to the "Create a script" sub-step of
  // http://www.whatwg.org/specs/web-apps/current-work/#execute-the-script-block
  nsAutoMicroTask mt;
  AutoEntryScript aes(globalObject, profilerLabelString.get(), true);
  JSContext* cx = aes.cx();
  JS::Rooted<JSObject*> global(cx, globalObject->GetGlobalJSObject());

  AutoSetProcessingScriptTag setProcessingScriptTag(context);

  nsresult rv;
  {
    if (aRequest->IsModuleRequest()) {
      // When a module is already loaded, it is not feched a second time and the
      // mDataType of the request might remain set to DataType::Unknown.
      MOZ_ASSERT(aRequest->IsTextSource() || aRequest->IsUnknownDataType());
      LOG(("ScriptLoadRequest (%p): Evaluate Module", aRequest));

      // currentScript is set to null for modules.
      AutoCurrentScriptUpdater scriptUpdater(this, nullptr);

      ModuleLoadRequest* request = aRequest->AsModuleRequest();
      MOZ_ASSERT(request->mModuleScript);
      MOZ_ASSERT(!request->mOffThreadToken);

      ModuleScript* moduleScript = request->mModuleScript;
      if (moduleScript->HasErrorToRethrow()) {
        LOG(("ScriptLoadRequest (%p):   module has error to rethrow",
             aRequest));
        JS::Rooted<JS::Value> error(cx, moduleScript->ErrorToRethrow());
        JS_SetPendingException(cx, error);

        // For a dynamic import, the promise is rejected.  Otherwise an error is
        // either reported by AutoEntryScript.
        if (request->IsDynamicImport()) {
          FinishDynamicImport(cx, request, NS_OK);
        }
        return NS_OK;
      }

      JS::Rooted<JSObject*> module(cx, moduleScript->ModuleRecord());
      MOZ_ASSERT(module);

      rv = InitDebuggerDataForModuleTree(cx, request);
      NS_ENSURE_SUCCESS(rv, rv);

      rv = nsJSUtils::ModuleEvaluate(cx, module);
      MOZ_ASSERT(NS_FAILED(rv) == aes.HasException());

      if (NS_FAILED(rv)) {
        LOG(("ScriptLoadRequest (%p):   evaluation failed", aRequest));
        // For a dynamic import, the promise is rejected.  Otherwise an error is
        // either reported by AutoEntryScript.
        rv = NS_OK;
      }

      if (request->IsDynamicImport()) {
        FinishDynamicImport(cx, request, rv);
      }

      aRequest->mCacheInfo = nullptr;
    } else {
      // Update our current script.
      AutoCurrentScriptUpdater scriptUpdater(this, aRequest->Element());

      JS::CompileOptions options(cx);
      rv = FillCompileOptionsForRequest(aes, aRequest, global, &options);

      if (NS_SUCCEEDED(rv)) {
        if (aRequest->IsBytecode()) {
          TRACE_FOR_TEST(aRequest->Element(), "scriptloader_execute");
          nsJSUtils::ExecutionContext exec(cx, global);
          if (aRequest->mOffThreadToken) {
            LOG(("ScriptLoadRequest (%p): Decode Bytecode & Join and Execute",
                 aRequest));
            rv = exec.JoinDecode(&aRequest->mOffThreadToken);
          } else {
            LOG(("ScriptLoadRequest (%p): Decode Bytecode and Execute",
                 aRequest));
            rv = exec.Decode(options, aRequest->mScriptBytecode,
                             aRequest->mBytecodeOffset);
          }

          if (rv == NS_OK) {
            rv = ExecuteCompiledScript(cx, aRequest, exec);
          }

          // We do not expect to be saving anything when we already have some
          // bytecode.
          MOZ_ASSERT(!aRequest->mCacheInfo);
        } else {
          MOZ_ASSERT(aRequest->IsSource());
          JS::Rooted<JSScript*> script(cx);
          bool encodeBytecode = ShouldCacheBytecode(aRequest);

          {
            nsJSUtils::ExecutionContext exec(cx, global);
            exec.SetEncodeBytecode(encodeBytecode);
            TRACE_FOR_TEST(aRequest->Element(), "scriptloader_execute");
            if (aRequest->mOffThreadToken) {
              // Off-main-thread parsing.
              LOG(
                  ("ScriptLoadRequest (%p): Join (off-thread parsing) and "
                   "Execute",
                   aRequest));
              if (aRequest->IsBinASTSource()) {
                rv = exec.JoinDecodeBinAST(&aRequest->mOffThreadToken);
              } else {
                MOZ_ASSERT(aRequest->IsTextSource());
                rv = exec.JoinCompile(&aRequest->mOffThreadToken);
              }
            } else {
              // Main thread parsing (inline and small scripts)
              LOG(("ScriptLoadRequest (%p): Compile And Exec", aRequest));
              if (aRequest->IsBinASTSource()) {
                rv = exec.DecodeBinAST(options,
                                       aRequest->ScriptBinASTData().begin(),
                                       aRequest->ScriptBinASTData().length());
              } else {
                MOZ_ASSERT(aRequest->IsTextSource());
                auto srcBuf = GetScriptSource(cx, aRequest);

                if (srcBuf) {
                  rv = exec.Compile(options, *srcBuf);
                } else {
                  rv = NS_ERROR_OUT_OF_MEMORY;
                }
              }
            }

            if (rv == NS_OK) {
              script = exec.GetScript();
              rv = ExecuteCompiledScript(cx, aRequest, exec);
            }
          }

          // Queue the current script load request to later save the bytecode.
          if (script && encodeBytecode) {
            aRequest->SetScript(script);
            TRACE_FOR_TEST(aRequest->Element(), "scriptloader_encode");
            MOZ_ASSERT(aRequest->mBytecodeOffset ==
                       aRequest->mScriptBytecode.length());
            RegisterForBytecodeEncoding(aRequest);
          } else {
            LOG(
                ("ScriptLoadRequest (%p): Bytecode-cache: disabled (rv = %X, "
                 "script = %p)",
                 aRequest, unsigned(rv), script.get()));
            TRACE_FOR_TEST_NONE(aRequest->Element(), "scriptloader_no_encode");
            aRequest->mCacheInfo = nullptr;
          }
        }
      }
    }

    // Even if we are not saving the bytecode of the current script, we have
    // to trigger the encoding of the bytecode, as the current script can
    // call functions of a script for which we are recording the bytecode.
    LOG(("ScriptLoadRequest (%p): ScriptLoader = %p", aRequest, this));
    MaybeTriggerBytecodeEncoding();
  }

  return rv;
}

/* static */
LoadedScript* ScriptLoader::GetActiveScript(JSContext* aCx) {
  JS::Value value = JS::GetScriptedCallerPrivate(aCx);
  if (value.isUndefined()) {
    return nullptr;
  }

  return static_cast<LoadedScript*>(value.toPrivate());
}

void ScriptLoader::RegisterForBytecodeEncoding(ScriptLoadRequest* aRequest) {
  MOZ_ASSERT(aRequest->mCacheInfo);
  MOZ_ASSERT(aRequest->mScript);
  mBytecodeEncodingQueue.AppendElement(aRequest);
}

void ScriptLoader::LoadEventFired() {
  mLoadEventFired = true;
  MaybeTriggerBytecodeEncoding();
}

void ScriptLoader::MaybeTriggerBytecodeEncoding() {
  // If we already gave up, ensure that we are not going to enqueue any script,
  // and that we finalize them properly.
  if (mGiveUpEncoding) {
    LOG(("ScriptLoader (%p): Keep giving-up bytecode encoding.", this));
    GiveUpBytecodeEncoding();
    return;
  }

  // We wait for the load event to be fired before saving the bytecode of
  // any script to the cache. It is quite common to have load event
  // listeners trigger more JavaScript execution, that we want to save as
  // part of this start-up bytecode cache.
  if (!mLoadEventFired) {
    LOG(("ScriptLoader (%p): Wait for the load-end event to fire.", this));
    return;
  }

  // No need to fire any event if there is no bytecode to be saved.
  if (mBytecodeEncodingQueue.isEmpty()) {
    LOG(("ScriptLoader (%p): No script in queue to be encoded.", this));
    return;
  }

  // Wait until all scripts are loaded before saving the bytecode, such that
  // we capture most of the intialization of the page.
  if (HasPendingRequests()) {
    LOG(("ScriptLoader (%p): Wait for other pending request to finish.", this));
    return;
  }

  // Create a new runnable dedicated to encoding the content of the bytecode of
  // all enqueued scripts when the document is idle. In case of failure, we
  // give-up on encoding the bytecode.
  nsCOMPtr<nsIRunnable> encoder = NewRunnableMethod(
      "ScriptLoader::EncodeBytecode", this, &ScriptLoader::EncodeBytecode);
  if (NS_FAILED(NS_DispatchToCurrentThreadQueue(encoder.forget(),
                                                EventQueuePriority::Idle))) {
    GiveUpBytecodeEncoding();
    return;
  }

  LOG(("ScriptLoader (%p): Schedule bytecode encoding.", this));
}

void ScriptLoader::EncodeBytecode() {
  LOG(("ScriptLoader (%p): Start bytecode encoding.", this));

  // If any script got added in the previous loop cycle, wait until all
  // remaining script executions are completed, such that we capture most of
  // the initialization.
  if (HasPendingRequests()) {
    return;
  }

  nsCOMPtr<nsIScriptGlobalObject> globalObject = GetScriptGlobalObject();
  if (!globalObject) {
    GiveUpBytecodeEncoding();
    return;
  }

  nsCOMPtr<nsIScriptContext> context = globalObject->GetScriptContext();
  if (!context) {
    GiveUpBytecodeEncoding();
    return;
  }

  AutoEntryScript aes(globalObject, "encode bytecode", true);
  RefPtr<ScriptLoadRequest> request;
  while (!mBytecodeEncodingQueue.isEmpty()) {
    request = mBytecodeEncodingQueue.StealFirst();
    EncodeRequestBytecode(aes.cx(), request);
    request->mScriptBytecode.clearAndFree();
    request->DropBytecodeCacheReferences();
  }
}

void ScriptLoader::EncodeRequestBytecode(JSContext* aCx,
                                         ScriptLoadRequest* aRequest) {
  using namespace mozilla::Telemetry;
  nsresult rv = NS_OK;
  MOZ_ASSERT(aRequest->mCacheInfo);
  auto bytecodeFailed = mozilla::MakeScopeExit([&]() {
    TRACE_FOR_TEST_NONE(aRequest->Element(), "scriptloader_bytecode_failed");
  });

  JS::RootedScript script(aCx, aRequest->mScript);
  if (!JS::FinishIncrementalEncoding(aCx, script, aRequest->mScriptBytecode)) {
    LOG(("ScriptLoadRequest (%p): Cannot serialize bytecode", aRequest));
    return;
  }

  if (aRequest->mScriptBytecode.length() >= UINT32_MAX) {
    LOG(
        ("ScriptLoadRequest (%p): Bytecode cache is too large to be decoded "
         "correctly.",
         aRequest));
    return;
  }

  // Open the output stream to the cache entry alternate data storage. This
  // might fail if the stream is already open by another request, in which
  // case, we just ignore the current one.
  nsCOMPtr<nsIAsyncOutputStream> output;
  rv = aRequest->mCacheInfo->OpenAlternativeOutputStream(
      nsContentUtils::JSBytecodeMimeType(), aRequest->mScriptBytecode.length(),
      getter_AddRefs(output));
  if (NS_FAILED(rv)) {
    LOG(
        ("ScriptLoadRequest (%p): Cannot open bytecode cache (rv = %X, output "
         "= %p)",
         aRequest, unsigned(rv), output.get()));
    return;
  }
  MOZ_ASSERT(output);

  auto closeOutStream = mozilla::MakeScopeExit([&]() {
    rv = output->CloseWithStatus(rv);
    LOG(("ScriptLoadRequest (%p): Closing (rv = %X)", aRequest, unsigned(rv)));
  });

  uint32_t n;
  rv = output->Write(reinterpret_cast<char*>(aRequest->mScriptBytecode.begin()),
                     aRequest->mScriptBytecode.length(), &n);
  LOG((
      "ScriptLoadRequest (%p): Write bytecode cache (rv = %X, length = %u, "
      "written = %u)",
      aRequest, unsigned(rv), unsigned(aRequest->mScriptBytecode.length()), n));
  if (NS_FAILED(rv)) {
    return;
  }

  MOZ_RELEASE_ASSERT(aRequest->mScriptBytecode.length() == n);

  bytecodeFailed.release();
  TRACE_FOR_TEST_NONE(aRequest->Element(), "scriptloader_bytecode_saved");
}

void ScriptLoader::GiveUpBytecodeEncoding() {
  // If the document went away prematurely, we still want to set this, in order
  // to avoid queuing more scripts.
  mGiveUpEncoding = true;

  // Ideally we prefer to properly end the incremental encoder, such that we
  // would not keep a large buffer around.  If we cannot, we fallback on the
  // removal of all request from the current list and these large buffers would
  // be removed at the same time as the source object.
  nsCOMPtr<nsIScriptGlobalObject> globalObject = GetScriptGlobalObject();
  Maybe<AutoEntryScript> aes;

  if (globalObject) {
    nsCOMPtr<nsIScriptContext> context = globalObject->GetScriptContext();
    if (context) {
      aes.emplace(globalObject, "give-up bytecode encoding", true);
    }
  }

  while (!mBytecodeEncodingQueue.isEmpty()) {
    RefPtr<ScriptLoadRequest> request = mBytecodeEncodingQueue.StealFirst();
    LOG(("ScriptLoadRequest (%p): Cannot serialize bytecode", request.get()));
    TRACE_FOR_TEST_NONE(request->Element(), "scriptloader_bytecode_failed");

    if (aes.isSome()) {
      JS::RootedScript script(aes->cx(), request->mScript);
      Unused << JS::FinishIncrementalEncoding(aes->cx(), script,
                                              request->mScriptBytecode);
    }

    request->mScriptBytecode.clearAndFree();
    request->DropBytecodeCacheReferences();
  }
}

bool ScriptLoader::HasPendingRequests() {
  return mParserBlockingRequest || !mXSLTRequests.isEmpty() ||
         !mLoadedAsyncRequests.isEmpty() ||
         !mNonAsyncExternalScriptInsertedRequests.isEmpty() ||
         !mDeferRequests.isEmpty() || !mDynamicImportRequests.isEmpty() ||
         !mPendingChildLoaders.IsEmpty();
}

void ScriptLoader::ProcessPendingRequestsAsync() {
  if (HasPendingRequests()) {
    nsCOMPtr<nsIRunnable> task =
        NewRunnableMethod("dom::ScriptLoader::ProcessPendingRequests", this,
                          &ScriptLoader::ProcessPendingRequests);
    if (mDocument) {
      mDocument->Dispatch(TaskCategory::Other, task.forget());
    } else {
      NS_DispatchToCurrentThread(task.forget());
    }
  }
}

void ScriptLoader::ProcessPendingRequests() {
  RefPtr<ScriptLoadRequest> request;

  if (mParserBlockingRequest && mParserBlockingRequest->IsReadyToRun() &&
      ReadyToExecuteParserBlockingScripts()) {
    request.swap(mParserBlockingRequest);
    UnblockParser(request);
    ProcessRequest(request);
    if (request->mWasCompiledOMT) {
      mDocument->UnblockOnload(false);
    }
    ContinueParserAsync(request);
  }

  while (ReadyToExecuteParserBlockingScripts() && !mXSLTRequests.isEmpty() &&
         mXSLTRequests.getFirst()->IsReadyToRun()) {
    request = mXSLTRequests.StealFirst();
    ProcessRequest(request);
  }

  while (ReadyToExecuteScripts() && !mLoadedAsyncRequests.isEmpty()) {
    request = mLoadedAsyncRequests.StealFirst();
    if (request->IsModuleRequest()) {
      ProcessRequest(request);
    } else {
      CompileOffThreadOrProcessRequest(request);
    }
  }

  while (ReadyToExecuteScripts() &&
         !mNonAsyncExternalScriptInsertedRequests.isEmpty() &&
         mNonAsyncExternalScriptInsertedRequests.getFirst()->IsReadyToRun()) {
    // Violate the HTML5 spec and execute these in the insertion order in
    // order to make LABjs and the "order" plug-in for RequireJS work with
    // their Gecko-sniffed code path. See
    // http://lists.w3.org/Archives/Public/public-html/2010Oct/0088.html
    request = mNonAsyncExternalScriptInsertedRequests.StealFirst();
    ProcessRequest(request);
  }

  if (mDocumentParsingDone && mXSLTRequests.isEmpty()) {
    while (ReadyToExecuteScripts() && !mDeferRequests.isEmpty() &&
           mDeferRequests.getFirst()->IsReadyToRun()) {
      request = mDeferRequests.StealFirst();
      ProcessRequest(request);
    }
  }

  while (!mPendingChildLoaders.IsEmpty() &&
         ReadyToExecuteParserBlockingScripts()) {
    RefPtr<ScriptLoader> child = mPendingChildLoaders[0];
    mPendingChildLoaders.RemoveElementAt(0);
    child->RemoveParserBlockingScriptExecutionBlocker();
  }

  if (mDocumentParsingDone && mDocument && !mParserBlockingRequest &&
      mNonAsyncExternalScriptInsertedRequests.isEmpty() &&
      mXSLTRequests.isEmpty() && mDeferRequests.isEmpty() &&
      MaybeRemovedDeferRequests()) {
    return ProcessPendingRequests();
  }

  if (mDocumentParsingDone && mDocument && !mParserBlockingRequest &&
      mLoadingAsyncRequests.isEmpty() && mLoadedAsyncRequests.isEmpty() &&
      mNonAsyncExternalScriptInsertedRequests.isEmpty() &&
      mXSLTRequests.isEmpty() && mDeferRequests.isEmpty()) {
    // No more pending scripts; time to unblock onload.
    // OK to unblock onload synchronously here, since callers must be
    // prepared for the world changing anyway.
    mDocumentParsingDone = false;
    mDocument->UnblockOnload(true);
  }
}

bool ScriptLoader::ReadyToExecuteParserBlockingScripts() {
  // Make sure the SelfReadyToExecuteParserBlockingScripts check is first, so
  // that we don't block twice on an ancestor.
  if (!SelfReadyToExecuteParserBlockingScripts()) {
    return false;
  }

  for (Document* doc = mDocument; doc; doc = doc->GetParentDocument()) {
    ScriptLoader* ancestor = doc->ScriptLoader();
    if (!ancestor->SelfReadyToExecuteParserBlockingScripts() &&
        ancestor->AddPendingChildLoader(this)) {
      AddParserBlockingScriptExecutionBlocker();
      return false;
    }
  }

  return true;
}

/* static */
nsresult ScriptLoader::ConvertToUTF16(nsIChannel* aChannel,
                                      const uint8_t* aData, uint32_t aLength,
                                      const nsAString& aHintCharset,
                                      Document* aDocument, char16_t*& aBufOut,
                                      size_t& aLengthOut) {
  if (!aLength) {
    aBufOut = nullptr;
    aLengthOut = 0;
    return NS_OK;
  }

  auto data = MakeSpan(aData, aLength);

  // The encoding info precedence is as follows from high to low:
  // The BOM
  // HTTP Content-Type (if name recognized)
  // charset attribute (if name recognized)
  // The encoding of the document

  UniquePtr<Decoder> unicodeDecoder;

  const Encoding* encoding;
  size_t bomLength;
  Tie(encoding, bomLength) = Encoding::ForBOM(data);
  if (encoding) {
    unicodeDecoder = encoding->NewDecoderWithBOMRemoval();
  }

  if (!unicodeDecoder && aChannel) {
    nsAutoCString label;
    if (NS_SUCCEEDED(aChannel->GetContentCharset(label)) &&
        (encoding = Encoding::ForLabel(label))) {
      unicodeDecoder = encoding->NewDecoderWithoutBOMHandling();
    }
  }

  if (!unicodeDecoder && (encoding = Encoding::ForLabel(aHintCharset))) {
    unicodeDecoder = encoding->NewDecoderWithoutBOMHandling();
  }

  if (!unicodeDecoder && aDocument) {
    unicodeDecoder =
        aDocument->GetDocumentCharacterSet()->NewDecoderWithoutBOMHandling();
  }

  if (!unicodeDecoder) {
    // Curiously, there are various callers that don't pass aDocument. The
    // fallback in the old code was ISO-8859-1, which behaved like
    // windows-1252.
    unicodeDecoder = WINDOWS_1252_ENCODING->NewDecoderWithoutBOMHandling();
  }

  CheckedInt<size_t> maxLength = unicodeDecoder->MaxUTF16BufferLength(aLength);
  if (!maxLength.isValid()) {
    aBufOut = nullptr;
    aLengthOut = 0;
    return NS_ERROR_OUT_OF_MEMORY;
  }

  size_t unicodeLength = maxLength.value();

  maxLength *= sizeof(char16_t);

  if (!maxLength.isValid()) {
    aBufOut = nullptr;
    aLengthOut = 0;
    return NS_ERROR_OUT_OF_MEMORY;
  }

  aBufOut = static_cast<char16_t*>(js_malloc(maxLength.value()));
  if (!aBufOut) {
    aLengthOut = 0;
    return NS_ERROR_OUT_OF_MEMORY;
  }

  uint32_t result;
  size_t read;
  size_t written;
  bool hadErrors;
  Tie(result, read, written, hadErrors) = unicodeDecoder->DecodeToUTF16(
      data, MakeSpan(aBufOut, unicodeLength), true);
  MOZ_ASSERT(result == kInputEmpty);
  MOZ_ASSERT(read == aLength);
  MOZ_ASSERT(written <= unicodeLength);
  Unused << hadErrors;
  aLengthOut = written;

  return NS_OK;
}

nsresult ScriptLoader::OnStreamComplete(
    nsIIncrementalStreamLoader* aLoader, ScriptLoadRequest* aRequest,
    nsresult aChannelStatus, nsresult aSRIStatus,
    SRICheckDataVerifier* aSRIDataVerifier) {
  NS_ASSERTION(aRequest, "null request in stream complete handler");
  NS_ENSURE_TRUE(aRequest, NS_ERROR_FAILURE);

  nsresult rv = VerifySRI(aRequest, aLoader, aSRIStatus, aSRIDataVerifier);

  if (NS_SUCCEEDED(rv)) {
    // If we are loading from source, save the computed SRI hash or a dummy SRI
    // hash in case we are going to save the bytecode of this script in the
    // cache.
    if (aRequest->IsSource()) {
      rv = SaveSRIHash(aRequest, aSRIDataVerifier);
    }

    if (NS_SUCCEEDED(rv)) {
      rv = PrepareLoadedRequest(aRequest, aLoader, aChannelStatus);
    }

    if (NS_FAILED(rv)) {
      ReportErrorToConsole(aRequest, rv);
    }
  }

  if (NS_FAILED(rv)) {
    // When loading bytecode, we verify the SRI hash. If it does not match the
    // one from the document we restart the load, forcing us to load the source
    // instead. If this happens do not remove the current request from script
    // loader's data structures or fire any events.
    if (aChannelStatus != NS_BINDING_RETARGETED) {
      HandleLoadError(aRequest, rv);
    }
  }

  // Process our request and/or any pending ones
  ProcessPendingRequests();

  return NS_OK;
}

nsresult ScriptLoader::VerifySRI(ScriptLoadRequest* aRequest,
                                 nsIIncrementalStreamLoader* aLoader,
                                 nsresult aSRIStatus,
                                 SRICheckDataVerifier* aSRIDataVerifier) const {
  nsCOMPtr<nsIRequest> channelRequest;
  aLoader->GetRequest(getter_AddRefs(channelRequest));
  nsCOMPtr<nsIChannel> channel;
  channel = do_QueryInterface(channelRequest);

  nsresult rv = NS_OK;
  if (!aRequest->mIntegrity.IsEmpty() && NS_SUCCEEDED((rv = aSRIStatus))) {
    MOZ_ASSERT(aSRIDataVerifier);
    MOZ_ASSERT(mReporter);

    nsAutoCString sourceUri;
    if (mDocument && mDocument->GetDocumentURI()) {
      mDocument->GetDocumentURI()->GetAsciiSpec(sourceUri);
    }
    rv = aSRIDataVerifier->Verify(aRequest->mIntegrity, channel, sourceUri,
                                  mReporter);
    if (channelRequest) {
      mReporter->FlushReportsToConsole(
          nsContentUtils::GetInnerWindowID(channelRequest));
    } else {
      mReporter->FlushConsoleReports(mDocument);
    }
    if (NS_FAILED(rv)) {
      rv = NS_ERROR_SRI_CORRUPT;
    }
  } else {
    nsCOMPtr<nsILoadInfo> loadInfo = channel->LoadInfo();

    if (loadInfo->GetEnforceSRI()) {
      MOZ_LOG(SRILogHelper::GetSriLog(), mozilla::LogLevel::Debug,
              ("ScriptLoader::OnStreamComplete, required SRI not found"));
      nsCOMPtr<nsIContentSecurityPolicy> csp;
      loadInfo->LoadingPrincipal()->GetCsp(getter_AddRefs(csp));
      nsAutoCString violationURISpec;
      mDocument->GetDocumentURI()->GetAsciiSpec(violationURISpec);
      uint32_t lineNo =
          aRequest->Element() ? aRequest->Element()->GetScriptLineNumber() : 0;
      uint32_t columnNo = aRequest->Element()
                              ? aRequest->Element()->GetScriptColumnNumber()
                              : 0;
      csp->LogViolationDetails(
          nsIContentSecurityPolicy::VIOLATION_TYPE_REQUIRE_SRI_FOR_SCRIPT,
          nullptr,  // triggering element
          nullptr,  // nsICSPEventListener
          NS_ConvertUTF8toUTF16(violationURISpec), EmptyString(), lineNo,
          columnNo, EmptyString(), EmptyString());
      rv = NS_ERROR_SRI_CORRUPT;
    }
  }

  return rv;
}

nsresult ScriptLoader::SaveSRIHash(
    ScriptLoadRequest* aRequest, SRICheckDataVerifier* aSRIDataVerifier) const {
  MOZ_ASSERT(aRequest->IsSource());
  MOZ_ASSERT(aRequest->mScriptBytecode.empty());

  // If the integrity metadata does not correspond to a valid hash function,
  // IsComplete would be false.
  if (!aRequest->mIntegrity.IsEmpty() && aSRIDataVerifier->IsComplete()) {
    // Encode the SRI computed hash.
    uint32_t len = aSRIDataVerifier->DataSummaryLength();
    if (!aRequest->mScriptBytecode.growBy(len)) {
      return NS_ERROR_OUT_OF_MEMORY;
    }
    aRequest->mBytecodeOffset = len;

    DebugOnly<nsresult> res = aSRIDataVerifier->ExportDataSummary(
        aRequest->mScriptBytecode.length(), aRequest->mScriptBytecode.begin());
    MOZ_ASSERT(NS_SUCCEEDED(res));
  } else {
    // Encode a dummy SRI hash.
    uint32_t len = SRICheckDataVerifier::EmptyDataSummaryLength();
    if (!aRequest->mScriptBytecode.growBy(len)) {
      return NS_ERROR_OUT_OF_MEMORY;
    }
    aRequest->mBytecodeOffset = len;

    DebugOnly<nsresult> res = SRICheckDataVerifier::ExportEmptyDataSummary(
        aRequest->mScriptBytecode.length(), aRequest->mScriptBytecode.begin());
    MOZ_ASSERT(NS_SUCCEEDED(res));
  }

  // Verify that the exported and predicted length correspond.
  mozilla::DebugOnly<uint32_t> srilen;
  MOZ_ASSERT(NS_SUCCEEDED(SRICheckDataVerifier::DataSummaryLength(
      aRequest->mScriptBytecode.length(), aRequest->mScriptBytecode.begin(),
      &srilen)));
  MOZ_ASSERT(srilen == aRequest->mBytecodeOffset);

  return NS_OK;
}

void ScriptLoader::ReportErrorToConsole(ScriptLoadRequest* aRequest,
                                        nsresult aResult) const {
  MOZ_ASSERT(aRequest);

  if (aRequest->IsPreload()) {
    // Skip reporting errors in preload requests. If the request is actually
    // used then we will report the error in ReportPreloadErrorsToConsole below.
    aRequest->mUnreportedPreloadError = aResult;
    return;
  }

  bool isScript = !aRequest->IsModuleRequest();
  const char* message;
  if (aResult == NS_ERROR_MALFORMED_URI) {
    message = isScript ? "ScriptSourceMalformed" : "ModuleSourceMalformed";
  } else if (aResult == NS_ERROR_DOM_BAD_URI) {
    message = isScript ? "ScriptSourceNotAllowed" : "ModuleSourceNotAllowed";
  } else if (net::UrlClassifierFeatureFactory::IsClassifierBlockingErrorCode(
                 aResult)) {
    // Blocking classifier error codes already show their own console messages.
    return;
  } else {
    message = isScript ? "ScriptSourceLoadFailed" : "ModuleSourceLoadFailed";
  }

  NS_ConvertUTF8toUTF16 url(aRequest->mURI->GetSpecOrDefault());
  const char16_t* params[] = {url.get()};

  nsIScriptElement* element = aRequest->Element();
  uint32_t lineNo = element ? element->GetScriptLineNumber() : 0;
  uint32_t columnNo = element ? element->GetScriptColumnNumber() : 0;

  nsContentUtils::ReportToConsole(
      nsIScriptError::warningFlag, NS_LITERAL_CSTRING("Script Loader"),
      mDocument, nsContentUtils::eDOM_PROPERTIES, message, params,
      ArrayLength(params), nullptr, EmptyString(), lineNo, columnNo);
}

void ScriptLoader::ReportPreloadErrorsToConsole(ScriptLoadRequest* aRequest) {
  if (NS_FAILED(aRequest->mUnreportedPreloadError)) {
    ReportErrorToConsole(aRequest, aRequest->mUnreportedPreloadError);
    aRequest->mUnreportedPreloadError = NS_OK;
  }

  if (aRequest->IsModuleRequest()) {
    for (auto childRequest : aRequest->AsModuleRequest()->mImports) {
      ReportPreloadErrorsToConsole(childRequest);
    }
  }
}

void ScriptLoader::HandleLoadError(ScriptLoadRequest* aRequest,
                                   nsresult aResult) {
  /*
   * Handle script not loading error because source was an tracking URL (or
   * fingerprinting, cryptoming, etc).
   * We make a note of this script node by including it in a dedicated
   * array of blocked tracking nodes under its parent document.
   */
  if (net::UrlClassifierFeatureFactory::IsClassifierBlockingErrorCode(
          aResult)) {
    nsCOMPtr<nsIContent> cont = do_QueryInterface(aRequest->Element());
    mDocument->AddBlockedNodeByClassifier(cont);
  }

  if (aRequest->IsModuleRequest() && !aRequest->mIsInline) {
    auto request = aRequest->AsModuleRequest();
    SetModuleFetchFinishedAndResumeWaitingRequests(request, aResult);
  }

  if (aRequest->mInDeferList) {
    MOZ_ASSERT_IF(aRequest->IsModuleRequest(),
                  aRequest->AsModuleRequest()->IsTopLevel());
    if (aRequest->isInList()) {
      RefPtr<ScriptLoadRequest> req = mDeferRequests.Steal(aRequest);
      FireScriptAvailable(aResult, req);
    }
  } else if (aRequest->mInAsyncList) {
    MOZ_ASSERT_IF(aRequest->IsModuleRequest(),
                  aRequest->AsModuleRequest()->IsTopLevel());
    if (aRequest->isInList()) {
      RefPtr<ScriptLoadRequest> req = mLoadingAsyncRequests.Steal(aRequest);
      FireScriptAvailable(aResult, req);
    }
  } else if (aRequest->mIsNonAsyncScriptInserted) {
    if (aRequest->isInList()) {
      RefPtr<ScriptLoadRequest> req =
          mNonAsyncExternalScriptInsertedRequests.Steal(aRequest);
      FireScriptAvailable(aResult, req);
    }
  } else if (aRequest->mIsXSLT) {
    if (aRequest->isInList()) {
      RefPtr<ScriptLoadRequest> req = mXSLTRequests.Steal(aRequest);
      FireScriptAvailable(aResult, req);
    }
  } else if (aRequest->IsPreload()) {
    if (aRequest->IsModuleRequest()) {
      aRequest->Cancel();
    }
    if (aRequest->IsTopLevel()) {
      MOZ_ALWAYS_TRUE(
          mPreloads.RemoveElement(aRequest, PreloadRequestComparator()));
    }
    MOZ_ASSERT(!aRequest->isInList());
    AccumulateCategorical(LABELS_DOM_SCRIPT_PRELOAD_RESULT::LoadError);
  } else if (aRequest->IsModuleRequest()) {
    ModuleLoadRequest* modReq = aRequest->AsModuleRequest();
    if (modReq->IsDynamicImport()) {
      MOZ_ASSERT(modReq->IsTopLevel());
      if (aRequest->isInList()) {
        RefPtr<ScriptLoadRequest> req = mDynamicImportRequests.Steal(aRequest);
        modReq->Cancel();
        FinishDynamicImport(modReq, aResult);
      }
    } else {
      MOZ_ASSERT(!modReq->IsTopLevel());
      MOZ_ASSERT(!modReq->isInList());
      modReq->Cancel();
      // The error is handled for the top level module.
    }
  } else if (mParserBlockingRequest == aRequest) {
    MOZ_ASSERT(!aRequest->isInList());
    mParserBlockingRequest = nullptr;
    UnblockParser(aRequest);

    // Ensure that we treat aRequest->Element() as our current parser-inserted
    // script while firing onerror on it.
    MOZ_ASSERT(aRequest->Element()->GetParserCreated());
    nsCOMPtr<nsIScriptElement> oldParserInsertedScript =
        mCurrentParserInsertedScript;
    mCurrentParserInsertedScript = aRequest->Element();
    FireScriptAvailable(aResult, aRequest);
    ContinueParserAsync(aRequest);
    mCurrentParserInsertedScript = oldParserInsertedScript;
  } else {
    // This happens for blocking requests cancelled by ParsingComplete().
    MOZ_ASSERT(aRequest->IsCanceled());
    MOZ_ASSERT(!aRequest->isInList());
  }
}

void ScriptLoader::UnblockParser(ScriptLoadRequest* aParserBlockingRequest) {
  aParserBlockingRequest->Element()->UnblockParser();
}

void ScriptLoader::ContinueParserAsync(
    ScriptLoadRequest* aParserBlockingRequest) {
  aParserBlockingRequest->Element()->ContinueParserAsync();
}

uint32_t ScriptLoader::NumberOfProcessors() {
  if (mNumberOfProcessors > 0) return mNumberOfProcessors;

  int32_t numProcs = PR_GetNumberOfProcessors();
  if (numProcs > 0) mNumberOfProcessors = numProcs;
  return mNumberOfProcessors;
}

static bool IsInternalURIScheme(nsIURI* uri) {
  bool isWebExt;
  if (NS_SUCCEEDED(uri->SchemeIs("moz-extension", &isWebExt)) && isWebExt) {
    return true;
  }

  bool isResource;
  if (NS_SUCCEEDED(uri->SchemeIs("resource", &isResource)) && isResource) {
    return true;
  }

  return false;
}

nsresult ScriptLoader::PrepareLoadedRequest(ScriptLoadRequest* aRequest,
                                            nsIIncrementalStreamLoader* aLoader,
                                            nsresult aStatus) {
  if (NS_FAILED(aStatus)) {
    return aStatus;
  }

  if (aRequest->IsCanceled()) {
    return NS_BINDING_ABORTED;
  }
  MOZ_ASSERT(aRequest->IsLoading());
  CollectScriptTelemetry(aRequest);

  // If we don't have a document, then we need to abort further
  // evaluation.
  if (!mDocument) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  // If the load returned an error page, then we need to abort
  nsCOMPtr<nsIRequest> req;
  nsresult rv = aLoader->GetRequest(getter_AddRefs(req));
  NS_ASSERTION(req, "StreamLoader's request went away prematurely");
  NS_ENSURE_SUCCESS(rv, rv);

  nsCOMPtr<nsIHttpChannel> httpChannel = do_QueryInterface(req);
  if (httpChannel) {
    bool requestSucceeded;
    rv = httpChannel->GetRequestSucceeded(&requestSucceeded);
    if (NS_SUCCEEDED(rv) && !requestSucceeded) {
      return NS_ERROR_NOT_AVAILABLE;
    }

    nsAutoCString sourceMapURL;
    if (nsContentUtils::GetSourceMapURL(httpChannel, sourceMapURL)) {
      aRequest->mHasSourceMapURL = true;
      aRequest->mSourceMapURL = NS_ConvertUTF8toUTF16(sourceMapURL);
    }

    if (httpChannel->GetIsThirdPartyTrackingResource()) {
      aRequest->SetIsTracking();
    }
  }

  nsCOMPtr<nsIChannel> channel = do_QueryInterface(req);
  // If this load was subject to a CORS check, don't flag it with a separate
  // origin principal, so that it will treat our document's principal as the
  // origin principal.  Module loads always use CORS.
  if (!aRequest->IsModuleRequest() && aRequest->CORSMode() == CORS_NONE) {
    rv = nsContentUtils::GetSecurityManager()->GetChannelResultPrincipal(
        channel, getter_AddRefs(aRequest->mOriginPrincipal));
    NS_ENSURE_SUCCESS(rv, rv);
  }

  // This assertion could fire errorously if we ran out of memory when
  // inserting the request in the array. However it's an unlikely case
  // so if you see this assertion it is likely something else that is
  // wrong, especially if you see it more than once.
  NS_ASSERTION(mDeferRequests.Contains(aRequest) ||
                   mLoadingAsyncRequests.Contains(aRequest) ||
                   mNonAsyncExternalScriptInsertedRequests.Contains(aRequest) ||
                   mXSLTRequests.Contains(aRequest) ||
                   mDynamicImportRequests.Contains(aRequest) ||
                   (aRequest->IsModuleRequest() &&
                    !aRequest->AsModuleRequest()->IsTopLevel() &&
                    !aRequest->isInList()) ||
                   mPreloads.Contains(aRequest, PreloadRequestComparator()) ||
                   mParserBlockingRequest == aRequest,
               "aRequest should be pending!");

  nsCOMPtr<nsIURI> uri;
  rv = channel->GetOriginalURI(getter_AddRefs(uri));
  NS_ENSURE_SUCCESS(rv, rv);

  // Fixup moz-extension: and resource: URIs, because the channel URI will
  // point to file:, which won't be allowed to load.
  if (uri && IsInternalURIScheme(uri)) {
    aRequest->mBaseURL = uri;
  } else {
    channel->GetURI(getter_AddRefs(aRequest->mBaseURL));
  }

  if (aRequest->IsModuleRequest()) {
    MOZ_ASSERT(aRequest->IsSource());
    ModuleLoadRequest* request = aRequest->AsModuleRequest();

    // When loading a module, only responses with a JavaScript MIME type are
    // acceptable.
    nsAutoCString mimeType;
    channel->GetContentType(mimeType);
    NS_ConvertUTF8toUTF16 typeString(mimeType);
    if (!nsContentUtils::IsJavascriptMIMEType(typeString)) {
      return NS_ERROR_FAILURE;
    }

    // Attempt to compile off main thread.
    bool couldCompile = false;
    rv = AttemptAsyncScriptCompile(request, &couldCompile);
    NS_ENSURE_SUCCESS(rv, rv);
    if (couldCompile) {
      return NS_OK;
    }

    // Otherwise compile it right away and start fetching descendents.
    return ProcessFetchedModuleSource(request);
  }

  // The script is now loaded and ready to run.
  aRequest->SetReady();

  // If this is currently blocking the parser, attempt to compile it
  // off-main-thread.
  if (aRequest == mParserBlockingRequest && NumberOfProcessors() > 1) {
    MOZ_ASSERT(!aRequest->IsModuleRequest());
    bool couldCompile = false;
    nsresult rv = AttemptAsyncScriptCompile(aRequest, &couldCompile);
    NS_ENSURE_SUCCESS(rv, rv);
    if (couldCompile) {
      MOZ_ASSERT(aRequest->mProgress == ScriptLoadRequest::Progress::eCompiling,
                 "Request should be off-thread compiling now.");
      return NS_OK;
    }

    // If off-thread compile was rejected, continue with regular processing.
  }

  MaybeMoveToLoadedList(aRequest);

  return NS_OK;
}

void ScriptLoader::ParsingComplete(bool aTerminated) {
  if (mDeferEnabled) {
    // Have to check because we apparently get ParsingComplete
    // without BeginDeferringScripts in some cases
    mDocumentParsingDone = true;
  }
  mDeferEnabled = false;
  if (aTerminated) {
    mDeferRequests.Clear();
    mLoadingAsyncRequests.Clear();
    mLoadedAsyncRequests.Clear();
    mNonAsyncExternalScriptInsertedRequests.Clear();
    mXSLTRequests.Clear();

    for (ScriptLoadRequest* req = mDynamicImportRequests.getFirst(); req;
         req = req->getNext()) {
      req->Cancel();
      FinishDynamicImport(req->AsModuleRequest(), NS_ERROR_ABORT);
    }

    if (mParserBlockingRequest) {
      mParserBlockingRequest->Cancel();
      mParserBlockingRequest = nullptr;
    }
  }

  // Have to call this even if aTerminated so we'll correctly unblock
  // onload and all.
  ProcessPendingRequests();
}

void ScriptLoader::PreloadURI(
    nsIURI* aURI, const nsAString& aCharset, const nsAString& aType,
    const nsAString& aCrossOrigin, const nsAString& aIntegrity,
    bool aScriptFromHead, bool aAsync, bool aDefer, bool aNoModule,
    const mozilla::net::ReferrerPolicy aReferrerPolicy) {
  NS_ENSURE_TRUE_VOID(mDocument);
  // Check to see if scripts has been turned off.
  if (!mEnabled || !mDocument->IsScriptEnabled()) {
    return;
  }

  ScriptKind scriptKind = ScriptKind::eClassic;

  if (mDocument->ModuleScriptsEnabled()) {
    // Don't load nomodule scripts.
    if (aNoModule) {
      return;
    }

    static const char kASCIIWhitespace[] = "\t\n\f\r ";

    nsAutoString type(aType);
    type.Trim(kASCIIWhitespace);
    if (type.LowerCaseEqualsASCII("module")) {
      scriptKind = ScriptKind::eModule;
    }
  }

  if (scriptKind == ScriptKind::eClassic && !aType.IsEmpty() &&
      !nsContentUtils::IsJavascriptMIMEType(aType)) {
    // Unknown type.  Don't load it.
    return;
  }

  SRIMetadata sriMetadata;
  GetSRIMetadata(aIntegrity, &sriMetadata);

  RefPtr<ScriptLoadRequest> request = CreateLoadRequest(
      scriptKind, aURI, nullptr, mDocument->NodePrincipal(),
      Element::StringToCORSMode(aCrossOrigin), sriMetadata, aReferrerPolicy);
  request->mIsInline = false;
  request->mScriptFromHead = aScriptFromHead;
  request->SetScriptMode(aDefer, aAsync);
  request->SetIsPreloadRequest();

  if (LOG_ENABLED()) {
    nsAutoCString url;
    aURI->GetAsciiSpec(url);
    LOG(("ScriptLoadRequest (%p): Created preload request for %s",
         request.get(), url.get()));
  }

  nsresult rv = StartLoad(request);
  if (NS_FAILED(rv)) {
    return;
  }

  PreloadInfo* pi = mPreloads.AppendElement();
  pi->mRequest = request;
  pi->mCharset = aCharset;
}

void ScriptLoader::AddDeferRequest(ScriptLoadRequest* aRequest) {
  MOZ_ASSERT(aRequest->IsDeferredScript());
  MOZ_ASSERT(!aRequest->mInDeferList && !aRequest->mInAsyncList);

  aRequest->mInDeferList = true;
  mDeferRequests.AppendElement(aRequest);
  if (mDeferEnabled && aRequest == mDeferRequests.getFirst() && mDocument &&
      !mBlockingDOMContentLoaded) {
    MOZ_ASSERT(mDocument->GetReadyStateEnum() == Document::READYSTATE_LOADING);
    mBlockingDOMContentLoaded = true;
    mDocument->BlockDOMContentLoaded();
  }
}

void ScriptLoader::AddAsyncRequest(ScriptLoadRequest* aRequest) {
  MOZ_ASSERT(aRequest->IsAsyncScript());
  MOZ_ASSERT(!aRequest->mInDeferList && !aRequest->mInAsyncList);

  aRequest->mInAsyncList = true;
  if (aRequest->IsReadyToRun()) {
    mLoadedAsyncRequests.AppendElement(aRequest);
  } else {
    mLoadingAsyncRequests.AppendElement(aRequest);
  }
}

void ScriptLoader::MaybeMoveToLoadedList(ScriptLoadRequest* aRequest) {
  MOZ_ASSERT(aRequest->IsReadyToRun());

  // If it's async, move it to the loaded list.  aRequest->mInAsyncList really
  // _should_ be in a list, but the consequences if it's not are bad enough we
  // want to avoid trying to move it if it's not.
  if (aRequest->mInAsyncList) {
    MOZ_ASSERT(aRequest->isInList());
    if (aRequest->isInList()) {
      RefPtr<ScriptLoadRequest> req = mLoadingAsyncRequests.Steal(aRequest);
      mLoadedAsyncRequests.AppendElement(req);
    }
  }
}

bool ScriptLoader::MaybeRemovedDeferRequests() {
  if (mDeferRequests.isEmpty() && mDocument && mBlockingDOMContentLoaded) {
    mBlockingDOMContentLoaded = false;
    mDocument->UnblockDOMContentLoaded();
    return true;
  }
  return false;
}

#undef TRACE_FOR_TEST
#undef TRACE_FOR_TEST_BOOL
#undef TRACE_FOR_TEST_NONE

#undef LOG

}  // namespace dom
}  // namespace mozilla