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/* -*- 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 */
#ifndef js_loader_ScriptLoadRequest_h
#define js_loader_ScriptLoadRequest_h
#include "js/RootingAPI.h"
#include "js/SourceText.h"
#include "js/TypeDecls.h"
#include "mozilla/Atomics.h"
#include "mozilla/Assertions.h"
#include "mozilla/dom/SRIMetadata.h"
#include "mozilla/LinkedList.h"
#include "mozilla/Maybe.h"
#include "mozilla/PreloaderBase.h"
#include "mozilla/StaticPrefs_dom.h"
#include "mozilla/Variant.h"
#include "mozilla/Vector.h"
#include "nsCycleCollectionParticipant.h"
#include "nsIGlobalObject.h"
#include "LoadedScript.h"
#include "ScriptKind.h"
#include "ScriptFetchOptions.h"
#include "nsIScriptElement.h"
class nsICacheInfoChannel;
namespace mozilla::dom {
class ScriptLoadContext;
class WorkerLoadContext;
class WorkletLoadContext;
enum class RequestPriority : uint8_t;
} // namespace mozilla::dom
namespace mozilla::loader {
class SyncLoadContext;
} // namespace mozilla::loader
namespace JS {
namespace loader {
class LoadContextBase;
class ModuleLoadRequest;
class ScriptLoadRequestList;
* ScriptLoadRequest
* ScriptLoadRequest is a generic representation of a JavaScript script that
* will be loaded by a Script/Module loader. This representation is used by the
* DOM ScriptLoader and will be used by workers and MOZJSComponentLoader.
* The ScriptLoadRequest contains information about the kind of script (classic
* or module), the URI, and the ScriptFetchOptions associated with the script.
* It is responsible for holding the script data once the fetch is complete, or
* if the request is cached, the bytecode.
* Relationship to ScriptLoadContext:
* ScriptLoadRequest and ScriptLoadContexts have a circular pointer. A
* ScriptLoadContext augments the loading of a ScriptLoadRequest by providing
* additional information regarding the loading and evaluation behavior (see
* the ScriptLoadContext class for details). In terms of responsibility,
* the ScriptLoadRequest represents "What" is being loaded, and the
* ScriptLoadContext represents "How".
* TODO: see if we can use it in the jsshell script loader. We need to either
* remove ISUPPORTS or find a way to encorporate that in the jsshell. We would
* then only have one implementation of the script loader, and it would be
* tested whenever jsshell tests are run. This would mean finding another way to
* create ScriptLoadRequest lists.
class ScriptLoadRequest : public nsISupports,
private mozilla::LinkedListElement<ScriptLoadRequest>,
public LoadedScriptDelegate<ScriptLoadRequest> {
using super = LinkedListElement<ScriptLoadRequest>;
// Allow LinkedListElement<ScriptLoadRequest> to cast us to itself as needed.
friend class mozilla::LinkedListElement<ScriptLoadRequest>;
friend class ScriptLoadRequestList;
virtual ~ScriptLoadRequest();
using SRIMetadata = mozilla::dom::SRIMetadata;
ScriptLoadRequest(ScriptKind aKind, nsIURI* aURI,
mozilla::dom::ReferrerPolicy aReferrerPolicy,
ScriptFetchOptions* aFetchOptions,
const SRIMetadata& aIntegrity, nsIURI* aReferrer,
LoadContextBase* aContext);
using super::getNext;
using super::isInList;
template <typename T, typename D = JS::DeletePolicy<T>>
using UniquePtr = mozilla::UniquePtr<T, D>;
bool IsModuleRequest() const { return mKind == ScriptKind::eModule; }
bool IsImportMapRequest() const { return mKind == ScriptKind::eImportMap; }
ModuleLoadRequest* AsModuleRequest();
const ModuleLoadRequest* AsModuleRequest() const;
virtual bool IsTopLevel() const { return true; };
virtual void Cancel();
virtual void SetReady();
enum class State : uint8_t {
// Before any attempt at fetching resources from the cache we should first
// make sure that the resource does not yet exists in the cache. In which case
// we might simply alias its LoadedScript. Otherwise a new one would be
// created.
bool IsCheckingCache() const { return mState == State::CheckingCache; }
// Setup and load resources, to fill the LoadedScript and make it usable by
// the JavaScript engine.
bool IsFetching() const { return mState == State::Fetching; }
bool IsCompiling() const { return mState == State::Compiling; }
bool IsLoadingImports() const { return mState == State::LoadingImports; }
bool IsCancelingImports() const { return mState == State::CancelingImports; }
bool IsCanceled() const { return mState == State::Canceled; }
bool IsPendingFetchingError() const {
return mState == State::PendingFetchingError;
// Return whether the request has been completed, either successfully or
// otherwise.
bool IsFinished() const {
return mState == State::Ready || mState == State::Canceled;
mozilla::dom::RequestPriority FetchPriority() const {
return mFetchOptions->mFetchPriority;
enum mozilla::dom::ReferrerPolicy ReferrerPolicy() const {
return mReferrerPolicy;
void UpdateReferrerPolicy(mozilla::dom::ReferrerPolicy aReferrerPolicy) {
mReferrerPolicy = aReferrerPolicy;
enum ParserMetadata ParserMetadata() const {
return mFetchOptions->mParserMetadata;
const nsString& Nonce() const { return mFetchOptions->mNonce; }
nsIPrincipal* TriggeringPrincipal() const {
return mFetchOptions->mTriggeringPrincipal;
// Convert a CheckingCache ScriptLoadRequest into a Fetching one, by creating
// a new LoadedScript which is matching the ScriptKind provided when
// constructing this ScriptLoadRequest.
void NoCacheEntryFound();
void SetPendingFetchingError();
bool PassedConditionForBytecodeEncoding() const {
return mBytecodeEncodingPlan == BytecodeEncodingPlan::PassedCondition ||
mBytecodeEncodingPlan == BytecodeEncodingPlan::MarkedForEncode;
void MarkSkippedBytecodeEncoding() {
MOZ_ASSERT(mBytecodeEncodingPlan == BytecodeEncodingPlan::Uninitialized);
mBytecodeEncodingPlan = BytecodeEncodingPlan::Skipped;
void MarkPassedConditionForBytecodeEncoding() {
MOZ_ASSERT(mBytecodeEncodingPlan == BytecodeEncodingPlan::Uninitialized);
mBytecodeEncodingPlan = BytecodeEncodingPlan::PassedCondition;
bool IsMarkedForBytecodeEncoding() const {
return mBytecodeEncodingPlan == BytecodeEncodingPlan::MarkedForEncode;
void MarkForBytecodeEncoding() {
MOZ_ASSERT(mBytecodeEncodingPlan == BytecodeEncodingPlan::PassedCondition);
mBytecodeEncodingPlan = BytecodeEncodingPlan::MarkedForEncode;
void MarkScriptForBytecodeEncoding(JSScript* aScript);
mozilla::CORSMode CORSMode() const { return mFetchOptions->mCORSMode; }
void DropBytecodeCacheReferences();
bool HasLoadContext() const { return mLoadContext; }
bool HasScriptLoadContext() const;
bool HasWorkerLoadContext() const;
mozilla::dom::ScriptLoadContext* GetScriptLoadContext();
mozilla::loader::SyncLoadContext* GetSyncLoadContext();
mozilla::dom::WorkerLoadContext* GetWorkerLoadContext();
mozilla::dom::WorkletLoadContext* GetWorkletLoadContext();
const LoadedScript* getLoadedScript() const { return mLoadedScript.get(); }
LoadedScript* getLoadedScript() { return mLoadedScript.get(); }
* Set the request's mBaseURL, based on aChannel.
* aOriginalURI is the result of aChannel->GetOriginalURI.
void SetBaseURLFromChannelAndOriginalURI(nsIChannel* aChannel,
nsIURI* aOriginalURI);
const ScriptKind mKind; // Whether this is a classic script or a module
// script.
State mState; // Are we still waiting for a load to complete?
bool mFetchSourceOnly; // Request source, not cached bytecode.
enum class BytecodeEncodingPlan : uint8_t {
// This is not yet considered for encoding.
// This is marked for skipping the encoding.
// This fits the condition for the encoding (e.g. file size, fetch count).
// This is marked for encoding, with setting sufficient input,
// e.g. mScriptForBytecodeEncoding for script.
BytecodeEncodingPlan mBytecodeEncodingPlan =
// The referrer policy used for the initial fetch and for fetching any
// imported modules
enum mozilla::dom::ReferrerPolicy mReferrerPolicy;
RefPtr<ScriptFetchOptions> mFetchOptions;
const SRIMetadata mIntegrity;
const nsCOMPtr<nsIURI> mReferrer;
mSourceMapURL; // Holds source map url for loaded scripts
const nsCOMPtr<nsIURI> mURI;
nsCOMPtr<nsIPrincipal> mOriginPrincipal;
// Keep the URI's filename alive during off thread parsing.
// Also used by workers to report on errors while loading, and used by
// worklets as the file name in compile options.
nsAutoCString mURL;
// The base URL used for resolving relative module imports.
nsCOMPtr<nsIURI> mBaseURL;
// The loaded script holds the source / bytecode which is loaded.
// Currently it is used to hold information which are needed by the Debugger.
// Soon it would be used as a way to dissociate the LoadRequest from the
// loaded value, such that multiple request referring to the same content
// would share the same loaded script.
RefPtr<LoadedScript> mLoadedScript;
// Holds the top-level JSScript that corresponds to the current source, once
// it is parsed, and marked to be saved in the bytecode cache.
// NOTE: This field is not used for ModuleLoadRequest.
JS::Heap<JSScript*> mScriptForBytecodeEncoding;
// Holds the Cache information, which is used to register the bytecode
// on the cache entry, such that we can load it the next time.
nsCOMPtr<nsICacheInfoChannel> mCacheInfo;
// LoadContext for augmenting the load depending on the loading
// context (DOM, Worker, etc.)
RefPtr<LoadContextBase> mLoadContext;
// EarlyHintRegistrar id to connect the http channel back to the preload, with
// a default of value of 0 indicating that this request is not an early hints
// preload.
uint64_t mEarlyHintPreloaderId;
class ScriptLoadRequestList : private mozilla::LinkedList<ScriptLoadRequest> {
using super = mozilla::LinkedList<ScriptLoadRequest>;
void CancelRequestsAndClear();
#ifdef DEBUG
bool Contains(ScriptLoadRequest* aElem) const;
#endif // DEBUG
using super::getFirst;
using super::isEmpty;
void AppendElement(ScriptLoadRequest* aElem) {
already_AddRefed<ScriptLoadRequest> Steal(ScriptLoadRequest* aElem) {
return dont_AddRef(aElem);
already_AddRefed<ScriptLoadRequest> StealFirst() {
return Steal(getFirst());
void Remove(ScriptLoadRequest* aElem) {
inline void ImplCycleCollectionUnlink(ScriptLoadRequestList& aField) {
while (!aField.isEmpty()) {
RefPtr<ScriptLoadRequest> first = aField.StealFirst();
inline void ImplCycleCollectionTraverse(
nsCycleCollectionTraversalCallback& aCallback,
ScriptLoadRequestList& aField, const char* aName, uint32_t aFlags) {
for (ScriptLoadRequest* request = aField.getFirst(); request;
request = request->getNext()) {
CycleCollectionNoteChild(aCallback, request, aName, aFlags);
} // namespace loader
} // namespace JS
#endif // js_loader_ScriptLoadRequest_h