dom/promise/PromiseNativeHandler.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 file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_dom_PromiseNativeHandler_h
   8 #define mozilla_dom_PromiseNativeHandler_h
   9
  10 #include <functional>
  11 #include "js/TypeDecls.h"
  12 #include "nsISupports.h"
  13
  14 namespace mozilla {
  15 namespace dom {
  16
  17 class Promise;
  18
  19 /*
  20  * PromiseNativeHandler allows C++ to react to a Promise being
  21  * rejected/resolved. A PromiseNativeHandler can be appended to a Promise using
  22  * Promise::AppendNativeHandler().
  23  */
  24 class PromiseNativeHandler : public nsISupports {
  25  protected:
  26   virtual ~PromiseNativeHandler() = default;
  27
  28  public:
  29   MOZ_CAN_RUN_SCRIPT
  30   virtual void ResolvedCallback(JSContext* aCx,
  31                                 JS::Handle<JS::Value> aValue) = 0;
  32
  33   MOZ_CAN_RUN_SCRIPT
  34   virtual void RejectedCallback(JSContext* aCx,
  35                                 JS::Handle<JS::Value> aValue) = 0;
  36 };
  37
  38 // This class is used to set C++ callbacks once a dom Promise a resolved or
  39 // rejected.
  40 class DomPromiseListener final : public PromiseNativeHandler {
  41   NS_DECL_ISUPPORTS
  42
  43  public:
  44   using CallbackTypeResolved =
  45       std::function<void(JSContext*, JS::Handle<JS::Value>)>;
  46   using CallbackTypeRejected = std::function<void(nsresult)>;
  47
  48   explicit DomPromiseListener(Promise* aDOMPromise);
  49   DomPromiseListener(Promise* aDOMPromise, CallbackTypeResolved&& aResolve,
  50                      CallbackTypeRejected&& aReject);
  51   void SetResolvers(CallbackTypeResolved&& aResolve,
  52                     CallbackTypeRejected&& aReject);
  53   void ResolvedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue) override;
  54   void RejectedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue) override;
  55
  56  private:
  57   ~DomPromiseListener();
  58   Maybe<CallbackTypeResolved> mResolve;
  59   Maybe<CallbackTypeRejected> mReject;
  60 };
  61
  62 }  // namespace dom
  63 }  // namespace mozilla
  64
  65 #endif  // mozilla_dom_PromiseNativeHandler_h