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/RefPtr.h"
  11 #include "mozilla/dom/AbortFollower.h"
  12 #include "mozilla/DOMEventTargetHelper.h"
  13
  14 namespace mozilla::dom {
  15
  16 // AbortSignal the spec concept includes the concept of a child signal
  17 // "following" a parent signal -- internally, adding abort steps to the parent
  18 // signal that will then signal abort on the child signal -- to propagate
  19 // signaling abort from one signal to another.  See
  20 // <https://dom.spec.whatwg.org/#abortsignal-follow>.
  21 //
  22 // This requires that AbortSignal also inherit from AbortFollower.
  23 //
  24 // This ability to follow isn't directly exposed in the DOM; as of this writing
  25 // it appears only to be used internally in the Fetch API.  It might be a good
  26 // idea to split AbortSignal into an implementation that can follow, and an
  27 // implementation that can't, to provide this complexity only when it's needed.
  28 class AbortSignal : public DOMEventTargetHelper,
  29                     public AbortSignalImpl,
  30                     public AbortFollower {
  31  public:
  32   NS_DECL_ISUPPORTS_INHERITED
  33   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_INHERITED(AbortSignal,
  34                                                          DOMEventTargetHelper)
  35
  36   AbortSignal(nsIGlobalObject* aGlobalObject, bool aAborted,
  37               JS::Handle<JS::Value> aReason);
  38
  39   JSObject* WrapObject(JSContext* aCx,
  40                        JS::Handle<JSObject*> aGivenProto) override;
  41
  42   IMPL_EVENT_HANDLER(abort);
  43
  44   static already_AddRefed<AbortSignal> Abort(GlobalObject& aGlobal,
  45                                              JS::Handle<JS::Value> aReason);
  46
  47   static already_AddRefed<AbortSignal> Timeout(GlobalObject& aGlobal,
  48                                                uint64_t aMilliseconds,
  49                                                ErrorResult& aRv);
  50
  51   static already_AddRefed<AbortSignal> Any(
  52       GlobalObject& aGlobal,
  53       const Sequence<OwningNonNull<AbortSignal>>& aSignals);
  54
  55   void ThrowIfAborted(JSContext* aCx, ErrorResult& aRv);
  56
  57   // AbortSignalImpl
  58   void SignalAbort(JS::Handle<JS::Value> aReason) override;
  59
  60   // AbortFollower
  61   void RunAbortAlgorithm() override;
  62
  63   virtual bool IsTaskSignal() const { return false; }
  64
  65   bool Dependent() const;
  66
  67  protected:
  68   ~AbortSignal();
  69
  70   void MakeDependentOn(AbortSignal* aSignal);
  71
  72   nsTArray<WeakPtr<AbortSignal>> mSourceSignals;
  73   nsTArray<RefPtr<AbortSignal>> mDependentSignals;
  74
  75   bool mDependent;
  76 };
  77
  78 }  // namespace mozilla::dom
  79
  80 #endif  // mozilla_dom_AbortSignal_h