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 "js/Value.h"
  13 #include "mozilla/Maybe.h"
  14 #include "nsISupports.h"
  15
  16 namespace mozilla {
  17 namespace dom {
  18
  19 class Promise;
  20
  21 /*
  22  * PromiseNativeHandler allows C++ to react to a Promise being
  23  * rejected/resolved. A PromiseNativeHandler can be appended to a Promise using
  24  * Promise::AppendNativeHandler().
  25  */
  26 class PromiseNativeHandler : public nsISupports {
  27  protected:
  28   virtual ~PromiseNativeHandler() = default;
  29
  30  public:
  31   MOZ_CAN_RUN_SCRIPT
  32   virtual void ResolvedCallback(JSContext* aCx,
  33                                 JS::Handle<JS::Value> aValue) = 0;
  34
  35   MOZ_CAN_RUN_SCRIPT
  36   virtual void RejectedCallback(JSContext* aCx,
  37                                 JS::Handle<JS::Value> aValue) = 0;
  38 };
  39
  40 // This class is used to set C++ callbacks once a dom Promise a resolved or
  41 // rejected.
  42 class DomPromiseListener final : public PromiseNativeHandler {
  43   NS_DECL_ISUPPORTS
  44
  45  public:
  46   using CallbackTypeResolved =
  47       std::function<void(JSContext*, JS::Handle<JS::Value>)>;
  48   using CallbackTypeRejected = std::function<void(nsresult)>;
  49
  50   explicit DomPromiseListener(Promise* aDOMPromise);
  51   DomPromiseListener(Promise* aDOMPromise, CallbackTypeResolved&& aResolve,
  52                      CallbackTypeRejected&& aReject);
  53   void SetResolvers(CallbackTypeResolved&& aResolve,
  54                     CallbackTypeRejected&& aReject);
  55   void ResolvedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue) override;
  56   void RejectedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue) override;
  57
  58  private:
  59   ~DomPromiseListener();
  60   Maybe<CallbackTypeResolved> mResolve;
  61   Maybe<CallbackTypeRejected> mReject;
  62 };
  63
  64 }  // namespace dom
  65 }  // namespace mozilla
  66
  67 #endif  // mozilla_dom_PromiseNativeHandler_h