1 files changed, 197 insertions, 0 deletions
diff --git a/dom/script/ScriptLoadContext.h b/dom/script/ScriptLoadContext.h
new file mode 100644
index 0000000000..61aa074667
--- /dev/null
+++ b/dom/script/ScriptLoadContext.h
@@ -0,0 +1,197 @@
+/* -*- 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/RootingAPI.h"
+#include "js/SourceText.h"
+#include "js/TypeDecls.h"
+#include "js/loader/LoadContextBase.h"
+#include "js/loader/ScriptKind.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/PreloaderBase.h"
+#include "mozilla/StaticPrefs_dom.h"
+#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;
+
+namespace JS {
+class OffThreadToken;
+}  // namespace JS
+
+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, pointers
+ * to runnables (for cancellation and cleanup if a script is parsed offthread)
+ * and preload element specific controls.
+ *
+ */
+
+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)
+
+  // PreloaderBase
+  static void PrioritizeAsPreload(nsIChannel* aChannel);
+  virtual void PrioritizeAsPreload() override;
+
+  bool IsPreload() const;
+
+  bool CompileStarted() const;
+
+  JS::OffThreadToken** OffThreadTokenPtr() {
+    return mOffThreadToken ? &mOffThreadToken : nullptr;
+  }
+
+  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();
+
+  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.
+
+  // Off-thread parsing token. Set at the start of off-thread parsing and
+  // cleared when the result of the parse is used.
+  JS::OffThreadToken* mOffThreadToken;
+
+  // Runnable that is dispatched to the main thread when off-thread compilation
+  // completes.
+  RefPtr<Runnable> mRunnable;
+
+  uint32_t mLineNo;
+  uint32_t 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