1 files changed, 234 insertions, 0 deletions
diff --git a/toolkit/components/extensions/webidl-api/ExtensionEventListener.h b/toolkit/components/extensions/webidl-api/ExtensionEventListener.h
new file mode 100644
index 0000000000..e986e4f58b
--- /dev/null
+++ b/toolkit/components/extensions/webidl-api/ExtensionEventListener.h
@@ -0,0 +1,234 @@
+/* -*- 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_extensions_ExtensionEventListener_h
+#define mozilla_extensions_ExtensionEventListener_h
+
+#include "js/Promise.h"  // JS::IsPromiseObject
+#include "mozIExtensionAPIRequestHandling.h"
+#include "mozilla/dom/PromiseNativeHandler.h"
+#include "mozilla/dom/StructuredCloneHolder.h"
+#include "mozilla/dom/WorkerRunnable.h"
+#include "mozilla/dom/WorkerPrivate.h"
+
+#include "ExtensionBrowser.h"
+
+class nsIGlobalObject;
+
+namespace mozilla {
+
+namespace dom {
+class Function;
+}  // namespace dom
+
+namespace extensions {
+
+#define SLOT_SEND_RESPONSE_CALLBACK_INSTANCE 0
+
+// A class that represents a callback parameter passed to WebExtensions API
+// addListener / removeListener methods.
+//
+// Instances of this class are sent to the mozIExtensionAPIRequestHandler as
+// a property of the mozIExtensionAPIRequest.
+//
+// The mozIExtensionEventListener xpcom interface provides methods that allow
+// the mozIExtensionAPIRequestHandler running in the Main Thread to call the
+// underlying callback Function on its owning thread.
+class ExtensionEventListener final : public mozIExtensionEventListener {
+ public:
+  NS_DECL_MOZIEXTENSIONEVENTLISTENER
+  NS_DECL_THREADSAFE_ISUPPORTS
+
+  using CleanupCallback = std::function<void()>;
+  using ListenerCallOptions = mozIExtensionListenerCallOptions;
+  using APIObjectType = ListenerCallOptions::APIObjectType;
+  using CallbackType = ListenerCallOptions::CallbackType;
+
+  static already_AddRefed<ExtensionEventListener> Create(
+      nsIGlobalObject* aGlobal, ExtensionBrowser* aExtensionBrowser,
+      dom::Function* aCallback, CleanupCallback&& aCleanupCallback,
+      ErrorResult& aRv);
+
+  static bool IsPromise(JSContext* aCx, JS::Handle<JS::Value> aValue) {
+    if (!aValue.isObject()) {
+      return false;
+    }
+
+    JS::Rooted<JSObject*> obj(aCx, &aValue.toObject());
+    return JS::IsPromiseObject(obj);
+  }
+
+  dom::WorkerPrivate* GetWorkerPrivate() const;
+
+  RefPtr<dom::Function> GetCallback() const { return mCallback; }
+
+  nsCOMPtr<nsIGlobalObject> GetGlobalObject() const {
+    nsCOMPtr<nsIGlobalObject> global = do_QueryReferent(mGlobal);
+    return global;
+  }
+
+  ExtensionBrowser* GetExtensionBrowser() const { return mExtensionBrowser; }
+
+  void Cleanup() {
+    if (mWorkerRef) {
+      MutexAutoLock lock(mMutex);
+
+      mWorkerRef->Private()->AssertIsOnWorkerThread();
+      mWorkerRef = nullptr;
+    }
+
+    mGlobal = nullptr;
+    mCallback = nullptr;
+    mExtensionBrowser = nullptr;
+  }
+
+ private:
+  ExtensionEventListener(nsIGlobalObject* aGlobal,
+                         ExtensionBrowser* aExtensionBrowser,
+                         dom::Function* aCallback)
+      : mGlobal(do_GetWeakReference(aGlobal)),
+        mExtensionBrowser(aExtensionBrowser),
+        mCallback(aCallback),
+        mMutex("ExtensionEventListener::mMutex") {
+    MOZ_ASSERT(aGlobal);
+    MOZ_ASSERT(aExtensionBrowser);
+    MOZ_ASSERT(aCallback);
+  };
+
+  static UniquePtr<dom::StructuredCloneHolder> SerializeCallArguments(
+      const nsTArray<JS::Value>& aArgs, JSContext* aCx, ErrorResult& aRv);
+
+  ~ExtensionEventListener() { Cleanup(); };
+
+  // Accessed on the main and on the owning threads.
+  RefPtr<dom::ThreadSafeWorkerRef> mWorkerRef;
+
+  // Accessed only on the owning thread.
+  nsWeakPtr mGlobal;
+  RefPtr<ExtensionBrowser> mExtensionBrowser;
+  RefPtr<dom::Function> mCallback;
+
+  // Used to make sure we are not going to release the
+  // instance on the worker thread, while we are in the
+  // process of forwarding a call from the main thread.
+  Mutex mMutex MOZ_UNANNOTATED;
+};
+
+// A WorkerRunnable subclass used to call an ExtensionEventListener
+// in the thread that owns the dom::Function wrapped by the
+// ExtensionEventListener class.
+class ExtensionListenerCallWorkerRunnable final : public dom::WorkerRunnable {
+  friend class ExtensionListenerCallPromiseResultHandler;
+
+ public:
+  using ListenerCallOptions = mozIExtensionListenerCallOptions;
+  using APIObjectType = ListenerCallOptions::APIObjectType;
+  using CallbackType = ListenerCallOptions::CallbackType;
+
+  ExtensionListenerCallWorkerRunnable(
+      const RefPtr<ExtensionEventListener>& aExtensionEventListener,
+      UniquePtr<dom::StructuredCloneHolder> aArgsHolder,
+      ListenerCallOptions* aCallOptions,
+      RefPtr<dom::Promise> aPromiseRetval = nullptr)
+      : WorkerRunnable(aExtensionEventListener->GetWorkerPrivate(),
+                       "ExtensionListenerCallWorkerRunnable", WorkerThread),
+        mListener(aExtensionEventListener),
+        mArgsHolder(std::move(aArgsHolder)),
+        mPromiseResult(std::move(aPromiseRetval)),
+        mAPIObjectType(APIObjectType::NONE),
+        mCallbackArgType(CallbackType::CALLBACK_NONE) {
+    MOZ_ASSERT(NS_IsMainThread());
+    MOZ_ASSERT(aExtensionEventListener);
+
+    if (aCallOptions) {
+      aCallOptions->GetApiObjectType(&mAPIObjectType);
+      aCallOptions->GetApiObjectPrepended(&mAPIObjectPrepended);
+      aCallOptions->GetCallbackType(&mCallbackArgType);
+    }
+  }
+
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY
+  bool WorkerRun(JSContext* aCx, dom::WorkerPrivate* aWorkerPrivate) override;
+
+  bool IsCallResultCancelled() { return mIsCallResultCancelled; }
+
+ private:
+  ~ExtensionListenerCallWorkerRunnable() {
+    NS_ReleaseOnMainThread("~ExtensionListenerCallWorkerRunnable",
+                           mPromiseResult.forget());
+    ReleaseArgsHolder();
+    mListener = nullptr;
+  }
+
+  void ReleaseArgsHolder() {
+    if (NS_IsMainThread()) {
+      mArgsHolder = nullptr;
+    } else {
+      auto releaseArgsHolder = [argsHolder = std::move(mArgsHolder)]() {};
+      nsCOMPtr<nsIRunnable> runnable =
+          NS_NewRunnableFunction(__func__, std::move(releaseArgsHolder));
+      NS_DispatchToMainThread(runnable);
+    }
+  }
+
+  void DeserializeCallArguments(JSContext* aCx, dom::Sequence<JS::Value>& aArg,
+                                ErrorResult& aRv);
+
+  RefPtr<ExtensionEventListener> mListener;
+  UniquePtr<dom::StructuredCloneHolder> mArgsHolder;
+  RefPtr<dom::Promise> mPromiseResult;
+  bool mIsCallResultCancelled = false;
+  // Call Options.
+  bool mAPIObjectPrepended;
+  APIObjectType mAPIObjectType;
+  CallbackType mCallbackArgType;
+};
+
+// A class attached to the promise that should be resolved once the extension
+// event listener call has been handled, responsible for serializing resolved
+// values or rejected errors on the listener's owning thread and sending them to
+// the extension event listener caller running on the main thread.
+class ExtensionListenerCallPromiseResultHandler
+    : public dom::PromiseNativeHandler {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+
+  static void Create(
+      const RefPtr<dom::Promise>& aPromise,
+      const RefPtr<ExtensionListenerCallWorkerRunnable>& aWorkerRunnable,
+      dom::ThreadSafeWorkerRef* aWorkerRef);
+
+  // PromiseNativeHandler
+  void ResolvedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue,
+                        ErrorResult& aRv) override;
+  void RejectedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue,
+                        ErrorResult& aRv) override;
+
+  enum class PromiseCallbackType { Resolve, Reject };
+
+ private:
+  ExtensionListenerCallPromiseResultHandler(
+      dom::ThreadSafeWorkerRef* aWorkerRef,
+      RefPtr<ExtensionListenerCallWorkerRunnable> aWorkerRunnable)
+      : mWorkerRef(aWorkerRef), mWorkerRunnable(std::move(aWorkerRunnable)) {}
+
+  ~ExtensionListenerCallPromiseResultHandler() = default;
+
+  void WorkerRunCallback(JSContext* aCx, JS::Handle<JS::Value> aValue,
+                         PromiseCallbackType aCallbackType);
+
+  // Set and accessed only on the owning worker thread.
+  RefPtr<dom::ThreadSafeWorkerRef> mWorkerRef;
+
+  // Reference to the runnable created on and owned by the main thread,
+  // accessed on the worker thread and released on the owning thread.
+  RefPtr<ExtensionListenerCallWorkerRunnable> mWorkerRunnable;
+};
+
+}  // namespace extensions
+}  // namespace mozilla
+
+#endif  // mozilla_extensions_ExtensionEventListener_h