Quelle ModuleLoaderBase.h Sprache: C

/* -*- 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 js_loader_ModuleLoaderBase_h
#define js_loader_ModuleLoaderBase_h

#include "LoadedScript.h"
#include "ScriptLoadRequest.h"

#include "ImportMap.h"
#include "js/ColumnNumber.h"  // JS::ColumnNumberOneOrigin
#include "js/TypeDecls.h"     // JS::MutableHandle, JS::Handle, JS::Root
#include "js/Modules.h"
#include "nsRefPtrHashtable.h"
#include "nsCOMArray.h"
#include "nsCOMPtr.h"
#include "nsILoadInfo.h"    // nsSecurityFlags
#include "nsINode.h"        // nsIURI
#include "nsThreadUtils.h"  // GetMainThreadSerialEventTarget
#include "nsURIHashKey.h"
#include "mozilla/Attributes.h"  // MOZ_RAII
#include "mozilla/CORSMode.h"
#include "mozilla/MaybeOneOf.h"
#include "mozilla/UniquePtr.h"
#include "ResolveResult.h"

class nsIURI;

namespace mozilla {

class LazyLogModule;
union Utf8Unit;

}  // namespace mozilla

namespace JS {

class CompileOptions;

template <typename UnitT>
class SourceText;

namespace loader {

class ModuleLoaderBase;
class ModuleLoadRequest;
class ModuleScript;

/*
* [DOMDOC] Shared Classic/Module Script Methods
*
* The ScriptLoaderInterface defines the shared methods needed by both
* ScriptLoaders (loading classic scripts) and ModuleLoaders (loading module
* scripts). These include:
*
*     * Error Logging
*     * Generating the compile options
*     * Optional: Bytecode Encoding
*
* ScriptLoaderInterface does not provide any implementations.
* It enables the ModuleLoaderBase to reference back to the behavior implemented
* by a given ScriptLoader.
*
* Not all methods will be used by all ModuleLoaders. For example, Bytecode
* Encoding does not apply to workers, as we only work with source text there.
* Fully virtual methods are implemented by all.
*
*/

class ScriptLoaderInterface : public nsISupports {
public:
  // Alias common classes.
  using ScriptFetchOptions = JS::loader::ScriptFetchOptions;
  using ScriptKind = JS::loader::ScriptKind;
  using ScriptLoadRequest = JS::loader::ScriptLoadRequest;
  using ScriptLoadRequestList = JS::loader::ScriptLoadRequestList;
  using ModuleLoadRequest = JS::loader::ModuleLoadRequest;

  virtual ~ScriptLoaderInterface() = default;

  // In some environments, we will need to default to a base URI
  virtual nsIURI* GetBaseURI() const = 0;

  virtual void ReportErrorToConsole(ScriptLoadRequest* aRequest,
                                    nsresult aResult) const = 0;

  virtual void ReportWarningToConsole(
      ScriptLoadRequest* aRequest, const char* aMessageName,
      const nsTArray<nsString>& aParams = nsTArray<nsString>()) const = 0;

  // Fill in CompileOptions, as well as produce the introducer script for
  // subsequent calls to UpdateDebuggerMetadata
  virtual nsresult FillCompileOptionsForRequest(
      JSContext* cx, ScriptLoadRequest* aRequest, JS::CompileOptions* aOptions,
      JS::MutableHandle<JSScript*> aIntroductionScript) = 0;

  virtual void MaybePrepareModuleForBytecodeEncodingBeforeExecute(
      JSContext* aCx, ModuleLoadRequest* aRequest) {}

  virtual nsresult MaybePrepareModuleForBytecodeEncodingAfterExecute(
      ModuleLoadRequest* aRequest, nsresult aRv) {
    return NS_OK;
  }

  virtual void MaybeTriggerBytecodeEncoding() {}
};

class ModuleMapKey : public PLDHashEntryHdr {
public:
  using KeyType = const ModuleMapKey&;
  using KeyTypePointer = const ModuleMapKey*;

  ModuleMapKey(const nsIURI* aUri, const ModuleType aModuleType)
      : mUri(const_cast<nsIURI*>(aUri)), mModuleType(aModuleType) {
    MOZ_COUNT_CTOR(ModuleMapKey);
    MOZ_ASSERT(aUri);
  }
  explicit ModuleMapKey(KeyTypePointer aOther)
      : mUri(std::move(aOther->mUri)), mModuleType(aOther->mModuleType) {
    MOZ_COUNT_CTOR(ModuleMapKey);
    MOZ_ASSERT(mUri);
  }
  ModuleMapKey(ModuleMapKey&& aOther)
      : mUri(std::move(aOther.mUri)), mModuleType(aOther.mModuleType) {
    MOZ_COUNT_CTOR(ModuleMapKey);
    MOZ_ASSERT(mUri);
  }
  MOZ_COUNTED_DTOR(ModuleMapKey)

  bool KeyEquals(KeyTypePointer aKey) const {
    if (mModuleType != aKey->mModuleType) {
      return false;
    }

    bool eq;
    if (NS_SUCCEEDED(mUri->Equals(aKey->mUri, &eq))) {
      return eq;
    }

    return false;
  }

  static KeyTypePointer KeyToPointer(KeyType key) { return &key; }

  static PLDHashNumber HashKey(KeyTypePointer aKey) {
    MOZ_ASSERT(aKey->mUri);
    nsAutoCString spec;
    // This is based on `nsURIHashKey`, and it ignores GetSpec() failures, so
    // do the same here.
    (void)aKey->mUri->GetSpec(spec);
    return mozilla::HashGeneric(mozilla::HashString(spec), aKey->mModuleType);
  }

  enum { ALLOW_MEMMOVE = true };

  const nsCOMPtr<nsIURI> mUri;
  const ModuleType mModuleType;
};

/*
* [DOMDOC] Module Loading
*
* ModuleLoaderBase provides support for loading module graphs as defined in the
* EcmaScript specification. A derived module loader class must be created for a
* specific use case (for example loading HTML module scripts). The derived
* class provides operations such as fetching of source code and scheduling of
* module execution.
*
* Module loading works in terms of 'requests' which hold data about modules as
* they move through the loading process. There may be more than one load
* request active for a single module URI, but the module is only loaded
* once. This is achieved by tracking all fetching and fetched modules in the
* module map.
*
* The module map is made up of two parts. A module that has been requested but
* has not finished fetching is represented by an entry in the mFetchingModules
* map. A module which has been fetched and compiled is represented by a
* ModuleScript in the mFetchedModules map.
*
* Module loading typically works as follows:
*
* 1.  The client ensures there is an instance of the derived module loader
*     class for its global or creates one if necessary.
*
* 2.  The client creates a ModuleLoadRequest object for the module to load and
*     calls the loader's StartModuleLoad() method. This is a top-level request,
*     i.e. not an import.
*
* 3.  The module loader calls the virtual method CanStartLoad() to check
*     whether the request should be loaded.
*
* 4.  If the module is not already present in the module map, the loader calls
*     the virtual method StartFetch() to set up an asynchronous operation to
*     fetch the module source.
*
* 5.  When the fetch operation is complete, the derived loader calls
*     OnFetchComplete() passing an error code to indicate success or failure.
*
* 6.  On success, the loader attempts to create a module script by calling the
*     virtual CompileFetchedModule() method.
*
* 7.  If compilation is successful, the loader creates load requests for any
*     imported modules if present. If so, the process repeats from step 3.
*
* 8.  When a load request is completed, the virtual OnModuleLoadComplete()
*     method is called. This is called for the top-level request and import
*     requests.
*
* 9.  The client calls InstantiateModuleGraph() for the top-level request. This
*     links the loaded module graph.
*
* 10. The client calls EvaluateModule() to execute the top-level module.
*/
class ModuleLoaderBase : public nsISupports {
public:
  // Alias common classes.
  using LoadedScript = JS::loader::LoadedScript;
  using ScriptFetchOptions = JS::loader::ScriptFetchOptions;
  using ScriptLoadRequest = JS::loader::ScriptLoadRequest;
  using ModuleLoadRequest = JS::loader::ModuleLoadRequest;

private:
  /*
   * Represents an ongoing load operation for a URI initiated for one request
   * and which may have other requests waiting for it to complete.
   *
   * These are tracked in the mFetchingModules map.
   */
  class LoadingRequest final : public nsISupports {
    virtual ~LoadingRequest() = default;

   public:
    NS_DECL_CYCLE_COLLECTING_ISUPPORTS
    NS_DECL_CYCLE_COLLECTION_CLASS(LoadingRequest)

    // The request that initiated the load and which is currently fetching or
    // being compiled.
    RefPtr<ModuleLoadRequest> mRequest;

    // A list of any other requests for the same URI that are waiting for the
    // initial load to complete. These will be resumed by ResumeWaitingRequests
    // when that happens.
    nsTArray<RefPtr<ModuleLoadRequest>> mWaiting;
  };

  // Module map
  nsRefPtrHashtable<ModuleMapKey, LoadingRequest> mFetchingModules;
  nsRefPtrHashtable<ModuleMapKey, ModuleScript> mFetchedModules;

  // List of dynamic imports that are currently being loaded.
  ScriptLoadRequestList mDynamicImportRequests;

  nsCOMPtr<nsIGlobalObject> mGlobalObject;

  // If non-null, this module loader is overridden by the module loader pointed
  // by mOverriddenBy.
  // See ModuleLoaderBase::GetCurrentModuleLoader for more details.
  RefPtr<ModuleLoaderBase> mOverriddenBy;

  // https://html.spec.whatwg.org/multipage/webappapis.html#import-maps-allowed
  //
  // Each Window has an import maps allowed boolean, initially true.
  bool mImportMapsAllowed = true;

protected:
  RefPtr<ScriptLoaderInterface> mLoader;

  mozilla::UniquePtr<ImportMap> mImportMap;

  virtual ~ModuleLoaderBase();

#ifdef DEBUG
  const ScriptLoadRequestList& DynamicImportRequests() const {
    return mDynamicImportRequests;
  }
#endif

public:
  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  NS_DECL_CYCLE_COLLECTION_CLASS(ModuleLoaderBase)
  explicit ModuleLoaderBase(ScriptLoaderInterface* aLoader,
                            nsIGlobalObject* aGlobalObject);

  // Called to break cycles during shutdown to prevent memory leaks.
  void Shutdown();

  virtual nsIURI* GetBaseURI() const { return mLoader->GetBaseURI(); };

  using MaybeSourceText =
      mozilla::MaybeOneOf<JS::SourceText<char16_t>, JS::SourceText<Utf8Unit>>;

  // Methods that must be implemented by an extending class. These are called
  // internally by ModuleLoaderBase.

private:
  // Create a module load request for a static module import.
  virtual already_AddRefed<ModuleLoadRequest> CreateStaticImport(
      nsIURI* aURI, JS::ModuleType aModuleType, ModuleLoadRequest* aParent) = 0;

  // Called by HostImportModuleDynamically hook.
  virtual already_AddRefed<ModuleLoadRequest> CreateDynamicImport(
      JSContext* aCx, nsIURI* aURI, JS::ModuleType aModuleType,
      LoadedScript* aMaybeActiveScript, JS::Handle<JSString*> aSpecifier,
      JS::Handle<JSObject*> aPromise) = 0;

  virtual bool IsDynamicImportSupported() { return true; }

  // Called when dynamic import started successfully.
  virtual void OnDynamicImportStarted(ModuleLoadRequest* aRequest) {}

  // Check whether we can load a module. May return false with |aRvOut| set to
  // NS_OK to abort load without returning an error.
  virtual bool CanStartLoad(ModuleLoadRequest* aRequest, nsresult* aRvOut) = 0;

  // Start the process of fetching module source (or bytecode). This is only
  // called if CanStartLoad returned true.
  virtual nsresult StartFetch(ModuleLoadRequest* aRequest) = 0;

  // Create a JS module for a fetched module request. This might compile source
  // text or decode cached bytecode.
  virtual nsresult CompileFetchedModule(
      JSContext* aCx, JS::Handle<JSObject*> aGlobal,
      JS::CompileOptions& aOptions, ModuleLoadRequest* aRequest,
      JS::MutableHandle<JSObject*> aModuleOut) = 0;

  // Called when a module script has been loaded, including imports.
  virtual void OnModuleLoadComplete(ModuleLoadRequest* aRequest) = 0;

  virtual bool IsModuleEvaluationAborted(ModuleLoadRequest* aRequest) {
    return false;
  }

  // Get the error message when resolving failed. The default is to call
  // nsContentUtils::FormatLoalizedString. But currently
  // nsContentUtils::FormatLoalizedString cannot be called on a worklet thread,
  // see bug 1808301. So WorkletModuleLoader will override this function to
  // get the error message.
  virtual nsresult GetResolveFailureMessage(ResolveError aError,
                                            const nsAString& aSpecifier,
                                            nsAString& aResult);

  // Public API methods.

public:
  ScriptLoaderInterface* GetScriptLoaderInterface() const { return mLoader; }

  nsIGlobalObject* GetGlobalObject() const { return mGlobalObject; }

  bool HasFetchingModules() const;

  bool HasPendingDynamicImports() const;
  void CancelDynamicImport(ModuleLoadRequest* aRequest, nsresult aResult);
#ifdef DEBUG
  bool HasDynamicImport(const ModuleLoadRequest* aRequest) const;
#endif

  // Start a load for a module script URI. Returns immediately if the module is
  // already being loaded.
  nsresult StartModuleLoad(ModuleLoadRequest* aRequest);
  nsresult RestartModuleLoad(ModuleLoadRequest* aRequest);

  // Notify the module loader when a fetch started by StartFetch() completes.
  nsresult OnFetchComplete(ModuleLoadRequest* aRequest, nsresult aRv);

  // Link the module and all its imports. This must occur prior to evaluation.
  bool InstantiateModuleGraph(ModuleLoadRequest* aRequest);

  // Executes the module.
  // Implements https://html.spec.whatwg.org/#run-a-module-script
  nsresult EvaluateModule(ModuleLoadRequest* aRequest);

  // Evaluate a module in the given context. Does not push an entry to the
  // execution stack.
  nsresult EvaluateModuleInContext(JSContext* aCx, ModuleLoadRequest* aRequest,
                                   JS::ModuleErrorBehaviour errorBehaviour);

  nsresult StartDynamicImport(ModuleLoadRequest* aRequest);
  void ProcessDynamicImport(ModuleLoadRequest* aRequest);
  void CancelAndClearDynamicImports();

  // Process <script type="importmap">
  mozilla::UniquePtr<ImportMap> ParseImportMap(ScriptLoadRequest* aRequest);

  // Implements
  // https://html.spec.whatwg.org/multipage/webappapis.html#register-an-import-map
  void RegisterImportMap(mozilla::UniquePtr<ImportMap> aImportMap);

  bool HasImportMapRegistered() const { return bool(mImportMap); }

  // Getter for mImportMapsAllowed.
  bool IsImportMapAllowed() const { return mImportMapsAllowed; }
  // https://html.spec.whatwg.org/multipage/webappapis.html#disallow-further-import-maps
  void DisallowImportMaps() { mImportMapsAllowed = false; }

  // Returns true if the module for given module key is already fetched.
  bool IsModuleFetched(const ModuleMapKey& key) const;

  nsresult GetFetchedModuleURLs(nsTArray<nsCString>& aURLs);

  // Override the module loader with given loader until ResetOverride is called.
  // While overridden, ModuleLoaderBase::GetCurrentModuleLoader returns aLoader.
  //
  // This is used by mozJSModuleLoader to temporarily override the global's
  // module loader with SyncModuleLoader while importing a module graph
  // synchronously.
  void SetOverride(ModuleLoaderBase* aLoader);

  // Returns true if SetOverride was called.
  bool IsOverridden();

  // Returns true if SetOverride was called with aLoader.
  bool IsOverriddenBy(ModuleLoaderBase* aLoader);

  void ResetOverride();

  // Copy fetched modules to `aDest`.
  // `this` shouldn't have any fetching.
  // `aDest` shouldn't have any fetching or fetched modules.
  //
  // This is used when starting sync module load, to replicate the module cache
  // in the sync module loader pointed by `aDest`.
  void CopyModulesTo(ModuleLoaderBase* aDest);

  // Move all fetched modules to `aDest`.
  // Both `this` and `aDest` shouldn't have any fetching.
  //
  // This is used when finishing sync module load, to reflect the loaded modules
  // to the async module loader pointed by `aDest`.
  void MoveModulesTo(ModuleLoaderBase* aDest);

  // Internal methods.

private:
  friend class JS::loader::ModuleLoadRequest;

  static ModuleLoaderBase* GetCurrentModuleLoader(JSContext* aCx);
  static LoadedScript* GetLoadedScriptOrNull(
      JSContext* aCx, JS::Handle<JS::Value> aReferencingPrivate);

  static void EnsureModuleHooksInitialized();

  static JSObject* HostResolveImportedModule(
      JSContext* aCx, JS::Handle<JS::Value> aReferencingPrivate,
      JS::Handle<JSObject*> aModuleRequest);
  static bool HostPopulateImportMeta(JSContext* aCx,
                                     JS::Handle<JS::Value> aReferencingPrivate,
                                     JS::Handle<JSObject*> aMetaObject);
  static bool ImportMetaResolve(JSContext* cx, unsigned argc, Value* vp);
  static JSString* ImportMetaResolveImpl(
      JSContext* aCx, JS::Handle<JS::Value> aReferencingPrivate,
      JS::Handle<JSString*> aSpecifier);
  static bool HostImportModuleDynamically(
      JSContext* aCx, JS::Handle<JS::Value> aReferencingPrivate,
      JS::Handle<JSObject*> aModuleRequest, JS::Handle<JSObject*> aPromise);

  ResolveResult ResolveModuleSpecifier(LoadedScript* aScript,
                                       const nsAString& aSpecifier);

  nsresult HandleResolveFailure(JSContext* aCx, LoadedScript* aScript,
                                const nsAString& aSpecifier,
                                ResolveError aError, uint32_t aLineNumber,
                                JS::ColumnNumberOneOrigin aColumnNumber,
                                JS::MutableHandle<JS::Value> aErrorOut);

  enum class RestartRequest { No, Yes };
  nsresult StartOrRestartModuleLoad(ModuleLoadRequest* aRequest,
                                    RestartRequest aRestart);

  bool ModuleMapContainsURL(const ModuleMapKey& key) const;
  bool IsModuleFetching(const ModuleMapKey& key) const;
  void WaitForModuleFetch(ModuleLoadRequest* aRequest);
  void SetModuleFetchStarted(ModuleLoadRequest* aRequest);

  ModuleScript* GetFetchedModule(const ModuleMapKey& moduleMapKey) const;

  JS::Value FindFirstParseError(ModuleLoadRequest* aRequest);
  static nsresult InitDebuggerDataForModuleGraph(JSContext* aCx,
                                                 ModuleLoadRequest* aRequest);
  nsresult ResolveRequestedModules(
      ModuleLoadRequest* aRequest,
      nsTArray<ModuleMapKey>* aRequestedModulesOut);

  void SetModuleFetchFinishedAndResumeWaitingRequests(
      ModuleLoadRequest* aRequest, nsresult aResult);
  void ResumeWaitingRequests(LoadingRequest* aLoadingRequest, bool aSuccess);
  void ResumeWaitingRequest(ModuleLoadRequest* aRequest, bool aSuccess);

  void StartFetchingModuleDependencies(ModuleLoadRequest* aRequest);

  void StartFetchingModuleAndDependencies(ModuleLoadRequest* aParent,
                                          const ModuleMapKey& aRequestedModule);

  void InstantiateAndEvaluateDynamicImport(ModuleLoadRequest* aRequest);

  /**
   * Shorthand Wrapper for JSAPI FinishDynamicImport function for the reject
   * case where we do not have `aEvaluationPromise`. As there is no evaluation
   * Promise, JS::FinishDynamicImport will always reject.
   *
   * @param aRequest
   *        The module load request for the dynamic module.
   * @param aResult
   *        The result of running ModuleEvaluate -- If this is successful, then
   *        we can await the associated EvaluationPromise.
   */
  void FinishDynamicImportAndReject(ModuleLoadRequest* aRequest,
                                    nsresult aResult);

  /**
   * Wrapper for JSAPI FinishDynamicImport function. Takes an optional argument
   * `aEvaluationPromise` which, if null, exits early.
   *
   * This is the Top Level Await version, which works with modules which return
   * promises.
   *
   * @param aCX
   *        The JSContext for the module.
   * @param aRequest
   *        The module load request for the dynamic module.
   * @param aResult
   *        The result of running ModuleEvaluate -- If this is successful, then
   *        we can await the associated EvaluationPromise.
   * @param aEvaluationPromise
   *        The evaluation promise returned from evaluating the module. If this
   *        is null, JS::FinishDynamicImport will reject the dynamic import
   *        module promise.
   */
  static void FinishDynamicImport(JSContext* aCx, ModuleLoadRequest* aRequest,
                                  nsresult aResult,
                                  JS::Handle<JSObject*> aEvaluationPromise);

  void RemoveDynamicImport(ModuleLoadRequest* aRequest);

  nsresult CreateModuleScript(ModuleLoadRequest* aRequest);

  bool IsFetchingAndHasWaitingRequest(ModuleLoadRequest* aRequest);

  // The slot stored in ImportMetaResolve function.
  enum { ModulePrivateSlot = 0, SlotCount };

  // The number of args in ImportMetaResolve.
  static const uint32_t ImportMetaResolveNumArgs = 1;
  // The index of the 'specifier' argument in ImportMetaResolve.
  static const uint32_t ImportMetaResolveSpecifierArg = 0;

public:
  static mozilla::LazyLogModule gCspPRLog;
  static mozilla::LazyLogModule gModuleLoaderBaseLog;
};

// Override the target module loader with given module loader while this
// instance is on the stack.
class MOZ_RAII AutoOverrideModuleLoader {
public:
  AutoOverrideModuleLoader(ModuleLoaderBase* aTarget,
                           ModuleLoaderBase* aLoader);
  ~AutoOverrideModuleLoader();

private:
  RefPtr<ModuleLoaderBase> mTarget;
};

}  // namespace loader
}  // namespace JS

#endif  // js_loader_ModuleLoaderBase_h

quality100%

¤ Dauer der Verarbeitung: 0.30 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.