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Diffstat (limited to 'dom/script/ScriptLoadContext.h')
| -rw-r--r-- | dom/script/ScriptLoadContext.h | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/dom/script/ScriptLoadContext.h b/dom/script/ScriptLoadContext.h new file mode 100644 index 0000000000..74f7c6fe4f --- /dev/null +++ b/dom/script/ScriptLoadContext.h @@ -0,0 +1,253 @@ +/* -*- 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/. */ + +#ifndef mozilla_dom_ScriptLoadContext_h +#define mozilla_dom_ScriptLoadContext_h + +#include "js/AllocPolicy.h" +#include "js/ColumnNumber.h" // JS::ColumnNumberOneOrigin +#include "js/CompileOptions.h" // JS::OwningCompileOptions +#include "js/experimental/JSStencil.h" // JS::FrontendContext, JS::Stencil, JS::InstantiationStorage +#include "js/RootingAPI.h" +#include "js/SourceText.h" +#include "js/Transcoding.h" // JS::TranscodeResult +#include "js/TypeDecls.h" +#include "js/loader/LoadContextBase.h" +#include "js/loader/ScriptKind.h" +#include "mozilla/AlreadyAddRefed.h" +#include "mozilla/Atomics.h" +#include "mozilla/Assertions.h" +#include "mozilla/CORSMode.h" +#include "mozilla/dom/SRIMetadata.h" +#include "mozilla/LinkedList.h" +#include "mozilla/Maybe.h" +#include "mozilla/MaybeOneOf.h" +#include "mozilla/Mutex.h" +#include "mozilla/PreloaderBase.h" +#include "mozilla/RefPtr.h" +#include "mozilla/StaticPrefs_dom.h" +#include "mozilla/TaskController.h" // mozilla::Task +#include "mozilla/Utf8.h" // mozilla::Utf8Unit +#include "mozilla/Variant.h" +#include "mozilla/Vector.h" +#include "nsCOMPtr.h" +#include "nsCycleCollectionParticipant.h" +#include "nsIScriptElement.h" + +class nsICacheInfoChannel; +struct JSContext; + +namespace mozilla::dom { + +class Element; + +/* + * DOM specific ScriptLoadContext. + * + * ScriptLoadContexts augment the loading of a ScriptLoadRequest. They + * describe how a ScriptLoadRequests loading and evaluation needs to be + * augmented, based on the information provided by the loading context. In + * the case of the DOM, the ScriptLoadContext is used to identify how a script + * should be loaded according to information found in the HTML document into + * which it will be loaded. The following fields describe how the + * ScriptLoadRequest will be loaded. + * + * * mScriptMode + * stores the mode (Async, Sync, Deferred), and preload, which + * allows the ScriptLoader to decide if the script should be pushed + * offThread, or if the preloaded request should be used. + * * mScriptFromHead + * Set when the script tag is in the head, and should be treated as + * a blocking script + * * mIsInline + * Set for scripts whose bodies are inline in the html. In this case, + * the script does not need to be fetched first. + * * mIsXSLT + * Set if we are in an XSLT request. + * * mIsPreload + * Set for scripts that are preloaded in a + * <link rel="preload" as="script"> or <link rel="modulepreload"> + * element. + * + * In addition to describing how the ScriptLoadRequest will be loaded by the + * DOM ScriptLoader, the ScriptLoadContext contains fields that facilitate + * those custom behaviors, including support for offthread parsing and preload + * element specific controls. + * + */ + +// Base class for the off-thread compile or off-thread decode tasks. +class CompileOrDecodeTask : public mozilla::Task { + protected: + CompileOrDecodeTask(); + virtual ~CompileOrDecodeTask(); + + nsresult InitFrontendContext(); + + void DidRunTask(const MutexAutoLock& aProofOfLock, + RefPtr<JS::Stencil>&& aStencil); + + bool IsCancelled(const MutexAutoLock& aProofOfLock) const { + return mIsCancelled; + } + + public: + // Returns the result of the compilation or decode if it was successful. + // Returns nullptr otherwise, and sets pending exception on JSContext. + // + // aInstantiationStorage receives the storage allocated off main thread + // on successful case. + already_AddRefed<JS::Stencil> StealResult( + JSContext* aCx, JS::InstantiationStorage* aInstantiationStorage); + + // Cancel the task. + // If the task is already running, this waits for the task to finish. + void Cancel(); + + protected: + // This mutex is locked during running the task or cancelling task. + mozilla::Mutex mMutex; + + // The result of decode task, to distinguish throwing case and decode error. + JS::TranscodeResult mResult = JS::TranscodeResult::Ok; + + // An option used to compile the code, or the equivalent for decode. + // This holds the filename pointed by errors reported to JS::FrontendContext. + JS::OwningCompileOptions mOptions; + + // Owning-pointer for the context associated with the script compilation. + // + // The context is allocated on main thread in InitFrontendContext method, + // and is freed on any thread in the destructor. + JS::FrontendContext* mFrontendContext = nullptr; + + bool mIsCancelled = false; + + private: + // The result of the compilation or decode. + RefPtr<JS::Stencil> mStencil; + + JS::InstantiationStorage mInstantiationStorage; +}; + +class ScriptLoadContext : public JS::loader::LoadContextBase, + public PreloaderBase { + protected: + virtual ~ScriptLoadContext(); + + public: + explicit ScriptLoadContext(); + + NS_DECL_ISUPPORTS_INHERITED + NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(ScriptLoadContext, + JS::loader::LoadContextBase) + + static void PrioritizeAsPreload(nsIChannel* aChannel); + + bool IsPreload() const; + + bool CompileStarted() const; + + bool IsTracking() const { return mIsTracking; } + void SetIsTracking() { + MOZ_ASSERT(!mIsTracking); + mIsTracking = true; + } + + void BlockOnload(Document* aDocument); + + void MaybeUnblockOnload(); + + enum class ScriptMode : uint8_t { + eBlocking, + eDeferred, + eAsync, + eLinkPreload // this is a load initiated by <link rel="preload" + // as="script"> or <link rel="modulepreload"> tag + }; + + void SetScriptMode(bool aDeferAttr, bool aAsyncAttr, bool aLinkPreload); + + bool IsLinkPreloadScript() const { + return mScriptMode == ScriptMode::eLinkPreload; + } + + bool IsBlockingScript() const { return mScriptMode == ScriptMode::eBlocking; } + + bool IsDeferredScript() const { return mScriptMode == ScriptMode::eDeferred; } + + bool IsAsyncScript() const { return mScriptMode == ScriptMode::eAsync; } + + nsIScriptElement* GetScriptElement() const; + + // Make this request a preload (speculative) request. + void SetIsPreloadRequest() { + MOZ_ASSERT(!GetScriptElement()); + MOZ_ASSERT(!IsPreload()); + mIsPreload = true; + } + + // Make a preload request into an actual load request for the given element. + void SetIsLoadRequest(nsIScriptElement* aElement); + + FromParser GetParserCreated() const { + nsIScriptElement* element = GetScriptElement(); + if (!element) { + return NOT_FROM_PARSER; + } + return element->GetParserCreated(); + } + + // Used to output a string for the Gecko Profiler. + void GetProfilerLabel(nsACString& aOutString) override; + + void MaybeCancelOffThreadScript(); + + // Finish the off-main-thread compilation and return the result, or + // convert the compilation error to runtime error. + already_AddRefed<JS::Stencil> StealOffThreadResult( + JSContext* aCx, JS::InstantiationStorage* aInstantiationStorage); + + ScriptMode mScriptMode; // Whether this is a blocking, defer or async script. + bool mScriptFromHead; // Synchronous head script block loading of other non + // js/css content. + bool mIsInline; // Is the script inline or loaded? + bool mInDeferList; // True if we live in mDeferRequests. + bool mInAsyncList; // True if we live in mLoadingAsyncRequests or + // mLoadedAsyncRequests. + bool mIsNonAsyncScriptInserted; // True if we live in + // mNonAsyncExternalScriptInsertedRequests + bool mIsXSLT; // True if we live in mXSLTRequests. + bool mInCompilingList; // True if we are in mOffThreadCompilingRequests. + bool mIsTracking; // True if the script comes from a source on our + // tracking protection list. + bool mWasCompiledOMT; // True if the script has been compiled off main + // thread. + + // Task that performs off-thread compilation or off-thread decode. + // This field is used to take the result of the task, or cancel the task. + // + // Set to non-null on the task creation, and set to null when taking the + // result or cancelling the task. + RefPtr<CompileOrDecodeTask> mCompileOrDecodeTask; + + uint32_t mLineNo; + JS::ColumnNumberOneOrigin mColumnNo; + + // Set on scripts and top level modules. + bool mIsPreload; + + // Non-null if there is a document that this request is blocking from loading. + RefPtr<Document> mLoadBlockedDocument; + + // For preload requests, we defer reporting errors to the console until the + // request is used. + nsresult mUnreportedPreloadError; +}; + +} // namespace mozilla::dom + +#endif // mozilla_dom_ScriptLoadContext_h |