dom/abort/AbortSignal.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_AbortSignal_h
   8 #define mozilla_dom_AbortSignal_h
   9
  10 #include "mozilla/dom/AbortFollower.h"
  11 #include "mozilla/DOMEventTargetHelper.h"
  12
  13 namespace mozilla::dom {
  14
  15 // AbortSignal the spec concept includes the concept of a child signal
  16 // "following" a parent signal -- internally, adding abort steps to the parent
  17 // signal that will then signal abort on the child signal -- to propagate
  18 // signaling abort from one signal to another.  See
  19 // <https://dom.spec.whatwg.org/#abortsignal-follow>.
  20 //
  21 // This requires that AbortSignal also inherit from AbortFollower.
  22 //
  23 // This ability to follow isn't directly exposed in the DOM; as of this writing
  24 // it appears only to be used internally in the Fetch API.  It might be a good
  25 // idea to split AbortSignal into an implementation that can follow, and an
  26 // implementation that can't, to provide this complexity only when it's needed.
  27 class AbortSignal : public DOMEventTargetHelper,
  28                     public AbortSignalImpl,
  29                     public AbortFollower {
  30  public:
  31   NS_DECL_ISUPPORTS_INHERITED
  32   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_INHERITED(AbortSignal,
  33                                                          DOMEventTargetHelper)
  34
  35   AbortSignal(nsIGlobalObject* aGlobalObject, bool aAborted,
  36               JS::Handle<JS::Value> aReason);
  37
  38   JSObject* WrapObject(JSContext* aCx,
  39                        JS::Handle<JSObject*> aGivenProto) override;
  40
  41   IMPL_EVENT_HANDLER(abort);
  42
  43   static already_AddRefed<AbortSignal> Abort(GlobalObject& aGlobal,
  44                                              JS::Handle<JS::Value> aReason);
  45
  46   static already_AddRefed<AbortSignal> Timeout(GlobalObject& aGlobal,
  47                                                uint64_t aMilliseconds,
  48                                                ErrorResult& aRv);
  49
  50   void ThrowIfAborted(JSContext* aCx, ErrorResult& aRv);
  51
  52   // AbortSignalImpl
  53   void SignalAbort(JS::Handle<JS::Value> aReason) override;
  54
  55   // AbortFollower
  56   void RunAbortAlgorithm() override;
  57
  58   virtual bool IsTaskSignal() const { return false; }
  59
  60  protected:
  61   ~AbortSignal();
  62 };
  63
  64 }  // namespace mozilla::dom
  65
  66 #endif  // mozilla_dom_AbortSignal_h