dom/workers/Worker.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_dom_Worker_h
   8 #define mozilla_dom_Worker_h
   9
  10 #include "mozilla/Attributes.h"
  11 #include "mozilla/dom/DebuggerNotificationBinding.h"
  12 #include "mozilla/DOMEventTargetHelper.h"
  13 #include "mozilla/RefPtr.h"
  14 #include "mozilla/WeakPtr.h"
  15
  16 #ifdef XP_WIN
  17 #  undef PostMessage
  18 #endif
  19
  20 namespace mozilla::dom {
  21
  22 class EventWithOptionsRunnable;
  23 struct StructuredSerializeOptions;
  24 struct WorkerOptions;
  25 class WorkerPrivate;
  26
  27 class Worker : public DOMEventTargetHelper, public SupportsWeakPtr {
  28  public:
  29   NS_DECL_ISUPPORTS_INHERITED
  30   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_INHERITED(Worker,
  31                                                          DOMEventTargetHelper)
  32   static already_AddRefed<Worker> Constructor(const GlobalObject& aGlobal,
  33                                               const nsAString& aScriptURL,
  34                                               const WorkerOptions& aOptions,
  35                                               ErrorResult& aRv);
  36
  37   JSObject* WrapObject(JSContext* aCx,
  38                        JS::Handle<JSObject*> aGivenProto) override;
  39
  40   Maybe<EventCallbackDebuggerNotificationType> GetDebuggerNotificationType()
  41       const override {
  42     return Some(EventCallbackDebuggerNotificationType::Worker);
  43   }
  44
  45   // True if the worker is not yet closing from the perspective of this, the
  46   // owning thread, and therefore it's okay to post a message to the worker.
  47   // This is not a guarantee that the worker will process the message.
  48   //
  49   // This method will return false if `globalThis.close()` is invoked on the
  50   // worker before that method returns control to the caller and without waiting
  51   // for any task to be queued on this thread and run; this biases us to avoid
  52   // doing wasteful work but does mean if you are exposing something to content
  53   // that is specified to only transition as the result of a task, then you
  54   // should not use this method.
  55   //
  56   // The method name comes from
  57   // https://html.spec.whatwg.org/multipage/web-messaging.html#eligible-for-messaging
  58   // and is intended to convey whether it's okay to begin to take the steps to
  59   // create an `EventWithOptionsRunnable` to pass to `PostEventWithOptions`.
  60   // Note that early returning based on calling this method without performing
  61   // the structured serialization steps that would otherwise run is potentially
  62   // observable to content if content is in control of any of the payload in
  63   // such a way that an object with getters or a proxy could be provided.
  64   //
  65   // There is an identically named method on nsIGlobalObject and the semantics
  66   // are intentionally similar but please make sure you document your
  67   // assumptions when calling either method.
  68   bool IsEligibleForMessaging();
  69
  70   void PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
  71                    const Sequence<JSObject*>& aTransferable, ErrorResult& aRv);
  72
  73   void PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
  74                    const StructuredSerializeOptions& aOptions,
  75                    ErrorResult& aRv);
  76
  77   // Callers must call `IsEligibleForMessaging` before constructing an
  78   // `EventWithOptionsRunnable` subclass.
  79   void PostEventWithOptions(JSContext* aCx, JS::Handle<JS::Value> aOptions,
  80                             const Sequence<JSObject*>& aTransferable,
  81                             EventWithOptionsRunnable* aRunnable,
  82                             ErrorResult& aRv);
  83
  84   void Terminate();
  85
  86   IMPL_EVENT_HANDLER(error)
  87   IMPL_EVENT_HANDLER(message)
  88   IMPL_EVENT_HANDLER(messageerror)
  89
  90  protected:
  91   Worker(nsIGlobalObject* aGlobalObject,
  92          already_AddRefed<WorkerPrivate> aWorkerPrivate);
  93   ~Worker();
  94
  95   friend class EventWithOptionsRunnable;
  96   RefPtr<WorkerPrivate> mWorkerPrivate;
  97 };
  98
  99 }  // namespace mozilla::dom
 100
 101 #endif /* mozilla_dom_Worker_h */