1 files changed, 264 insertions, 0 deletions
diff --git a/js/xpconnect/loader/mozJSModuleLoader.h b/js/xpconnect/loader/mozJSModuleLoader.h
new file mode 100644
index 0000000000..e5a114a193
--- /dev/null
+++ b/js/xpconnect/loader/mozJSModuleLoader.h
@@ -0,0 +1,264 @@
+/* -*- 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 mozJSModuleLoader_h
+#define mozJSModuleLoader_h
+
+#include "ComponentModuleLoader.h"
+#include "mozilla/dom/ScriptSettings.h"
+#include "mozilla/FileLocation.h"
+#include "mozilla/MemoryReporting.h"
+#include "mozilla/StaticPtr.h"
+#include "nsIMemoryReporter.h"
+#include "nsISupports.h"
+#include "nsIURI.h"
+#include "nsClassHashtable.h"
+#include "jsapi.h"
+#include "js/experimental/JSStencil.h"
+#include "SkipCheckForBrokenURLOrZeroSized.h"
+
+#include "xpcpublic.h"
+
+class nsIFile;
+class ModuleLoaderInfo;
+
+namespace mozilla {
+class ScriptPreloader;
+}  // namespace mozilla
+
+namespace JS::loader {
+class ModuleLoadRequest;
+}  // namespace JS::loader
+
+#if defined(NIGHTLY_BUILD) || defined(MOZ_DEV_EDITION) || defined(DEBUG)
+#  define STARTUP_RECORDER_ENABLED
+#endif
+
+class mozJSModuleLoader final : public nsIMemoryReporter {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIMEMORYREPORTER
+
+  // Returns the list of all JSMs.
+  void GetLoadedModules(nsTArray<nsCString>& aLoadedModules);
+
+  // Returns the list of all ESMs.
+  nsresult GetLoadedESModules(nsTArray<nsCString>& aLoadedModules);
+
+  // Returns the list of all JSMs and ESMs.
+  nsresult GetLoadedJSAndESModules(nsTArray<nsCString>& aLoadedModules);
+
+  nsresult GetModuleImportStack(const nsACString& aLocation,
+                                nsACString& aRetval);
+
+  void FindTargetObject(JSContext* aCx, JS::MutableHandleObject aTargetObject);
+
+  static void InitStatics();
+  static void UnloadLoaders();
+  static void ShutdownLoaders();
+
+  static mozJSModuleLoader* Get() {
+    MOZ_ASSERT(sSelf, "Should have already created the module loader");
+    return sSelf;
+  }
+
+  static mozJSModuleLoader* GetDevToolsLoader() { return sDevToolsLoader; }
+  static mozJSModuleLoader* GetOrCreateDevToolsLoader();
+
+  nsresult ImportInto(const nsACString& aResourceURI,
+                      JS::HandleValue aTargetObj, JSContext* aCx, uint8_t aArgc,
+                      JS::MutableHandleValue aRetval);
+
+  // Load a JSM.
+  nsresult Import(JSContext* aCx, const nsACString& aResourceURI,
+                  JS::MutableHandleObject aModuleGlobal,
+                  JS::MutableHandleObject aModuleExports,
+                  bool aIgnoreExports = false);
+
+  // Load an ES6 module and all its dependencies.
+  nsresult ImportESModule(
+      JSContext* aCx, const nsACString& aResourceURI,
+      JS::MutableHandleObject aModuleNamespace,
+      mozilla::loader::SkipCheckForBrokenURLOrZeroSized aSkipCheck =
+          mozilla::loader::SkipCheckForBrokenURLOrZeroSized::No);
+
+  // Fallback from Import to ImportESModule.
+  nsresult TryFallbackToImportESModule(JSContext* aCx,
+                                       const nsACString& aResourceURI,
+                                       JS::MutableHandleObject aModuleGlobal,
+                                       JS::MutableHandleObject aModuleExports,
+                                       bool aIgnoreExports);
+
+  // If the request was handled by fallback before, fills the output and
+  // sets *aFound to true and returns NS_OK.
+  // If the request wasn't yet handled by fallback, sets *Found to false
+  // and returns NS_OK.
+  nsresult TryCachedFallbackToImportESModule(
+      JSContext* aCx, const nsACString& aResourceURI,
+      JS::MutableHandleObject aModuleGlobal,
+      JS::MutableHandleObject aModuleExports, bool aIgnoreExports,
+      bool* aFound);
+
+#ifdef STARTUP_RECORDER_ENABLED
+  void RecordImportStack(JSContext* aCx, const nsACString& aLocation);
+  void RecordImportStack(JSContext* aCx,
+                         JS::loader::ModuleLoadRequest* aRequest);
+#endif
+
+  nsresult Unload(const nsACString& aResourceURI);
+  nsresult IsModuleLoaded(const nsACString& aResourceURI, bool* aRetval);
+  nsresult IsJSModuleLoaded(const nsACString& aResourceURI, bool* aRetval);
+  nsresult IsESModuleLoaded(const nsACString& aResourceURI, bool* aRetval);
+  bool IsLoaderGlobal(JSObject* aObj) { return mLoaderGlobal == aObj; }
+  bool IsDevToolsLoader() const { return this == sDevToolsLoader; }
+
+  // Public methods for use from ComponentModuleLoader.
+  static bool IsTrustedScheme(nsIURI* aURI);
+  static nsresult LoadSingleModuleScript(
+      mozilla::loader::ComponentModuleLoader* aModuleLoader, JSContext* aCx,
+      JS::loader::ModuleLoadRequest* aRequest,
+      JS::MutableHandleScript aScriptOut);
+
+  size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf);
+
+  bool DefineJSServices(JSContext* aCx, JS::Handle<JSObject*> aGlobal);
+
+ protected:
+  mozJSModuleLoader();
+  ~mozJSModuleLoader();
+
+  friend class XPCJSRuntime;
+
+ private:
+  static mozilla::StaticRefPtr<mozJSModuleLoader> sSelf;
+  static mozilla::StaticRefPtr<mozJSModuleLoader> sDevToolsLoader;
+
+  void Unload();
+  void UnloadModules();
+
+  void CreateLoaderGlobal(JSContext* aCx, const nsACString& aLocation,
+                          JS::MutableHandleObject aGlobal);
+  void CreateDevToolsLoaderGlobal(JSContext* aCx, const nsACString& aLocation,
+                                  JS::MutableHandleObject aGlobal);
+
+  bool CreateJSServices(JSContext* aCx);
+
+  JSObject* GetSharedGlobal(JSContext* aCx);
+
+  static nsresult GetSourceFile(nsIURI* aResolvedURI, nsIFile** aSourceFileOut);
+
+  static bool LocationIsRealFile(nsIURI* aURI);
+
+  JSObject* PrepareObjectForLocation(JSContext* aCx, nsIFile* aModuleFile,
+                                     nsIURI* aURI, bool aRealFile);
+
+  nsresult ObjectForLocation(ModuleLoaderInfo& aInfo, nsIFile* aModuleFile,
+                             JS::MutableHandleObject aObject,
+                             JS::MutableHandleScript aTableScript,
+                             char** aLocation, bool aCatchException,
+                             JS::MutableHandleValue aException);
+
+  // Get the script for a given location, either from a cached stencil or by
+  // compiling it from source.
+  static nsresult GetScriptForLocation(JSContext* aCx, ModuleLoaderInfo& aInfo,
+                                       nsIFile* aModuleFile, bool aUseMemMap,
+                                       JS::MutableHandleScript aScriptOut,
+                                       char** aLocationOut = nullptr);
+
+  static already_AddRefed<JS::Stencil> CompileStencil(
+      JSContext* aCx, const JS::CompileOptions& aOptions,
+      JS::SourceText<mozilla::Utf8Unit>& aSource, bool aIsModule);
+  static JSScript* InstantiateStencil(JSContext* aCx, JS::Stencil* aStencil,
+                                      bool aIsModule);
+
+  nsresult ImportInto(const nsACString& aLocation, JS::HandleObject targetObj,
+                      JSContext* callercx, JS::MutableHandleObject vp);
+
+  class ModuleEntry {
+   public:
+    explicit ModuleEntry(JS::RootingContext* aRootingCx)
+        : obj(aRootingCx), exports(aRootingCx), thisObjectKey(aRootingCx) {
+      location = nullptr;
+    }
+
+    ~ModuleEntry() { Clear(); }
+
+    void Clear() {
+      if (obj) {
+        if (JS_HasExtensibleLexicalEnvironment(obj)) {
+          JS::RootedObject lexicalEnv(mozilla::dom::RootingCx(),
+                                      JS_ExtensibleLexicalEnvironment(obj));
+          JS_SetAllNonReservedSlotsToUndefined(lexicalEnv);
+        }
+        JS_SetAllNonReservedSlotsToUndefined(obj);
+        obj = nullptr;
+        thisObjectKey = nullptr;
+      }
+
+      if (location) {
+        free(location);
+      }
+
+      obj = nullptr;
+      thisObjectKey = nullptr;
+      location = nullptr;
+    }
+
+    size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
+
+    JS::PersistentRootedObject obj;
+    JS::PersistentRootedObject exports;
+    JS::PersistentRootedScript thisObjectKey;
+    char* location;
+    nsCString resolvedURL;
+  };
+
+  class FallbackModuleEntry {
+   public:
+    explicit FallbackModuleEntry(JS::RootingContext* aRootingCx)
+        : globalProxy(aRootingCx), moduleNamespace(aRootingCx) {}
+
+    ~FallbackModuleEntry() { Clear(); }
+
+    void Clear() {
+      globalProxy = nullptr;
+      moduleNamespace = nullptr;
+    }
+
+    size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const {
+      return aMallocSizeOf(this);
+    }
+
+    JS::PersistentRootedObject globalProxy;
+    JS::PersistentRootedObject moduleNamespace;
+  };
+
+  nsresult ExtractExports(JSContext* aCx, ModuleLoaderInfo& aInfo,
+                          ModuleEntry* aMod, JS::MutableHandleObject aExports);
+
+  nsClassHashtable<nsCStringHashKey, ModuleEntry> mImports;
+  nsTHashMap<nsCStringHashKey, ModuleEntry*> mInProgressImports;
+  nsClassHashtable<nsCStringHashKey, FallbackModuleEntry> mFallbackImports;
+#ifdef STARTUP_RECORDER_ENABLED
+  nsTHashMap<nsCStringHashKey, nsCString> mImportStacks;
+#endif
+
+  // A map of on-disk file locations which are loaded as modules to the
+  // pre-resolved URIs they were loaded from. Used to prevent the same file
+  // from being loaded separately, from multiple URLs.
+  nsClassHashtable<nsCStringHashKey, nsCString> mLocations;
+
+  bool mInitialized;
+#ifdef DEBUG
+  bool mIsInitializingLoaderGlobal = false;
+#endif
+  JS::PersistentRooted<JSObject*> mLoaderGlobal;
+  JS::PersistentRooted<JSObject*> mServicesObj;
+
+  RefPtr<mozilla::loader::ComponentModuleLoader> mModuleLoader;
+};
+
+#endif