dom/base/MozQueryInterface.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_MozQueryInterface
   8 #define mozilla_dom_MozQueryInterface
   9
  10 /**
  11  * This class implements an optimized QueryInterface method for
  12  * XPConnect-wrapped JS objects.
  13  *
  14  * For JavaScript callers, it behaves as an ordinary QueryInterface method,
  15  * returning its `this` object or throwing depending on the interface it was
  16  * passed.
  17  *
  18  * For native XPConnect callers, we bypass JSAPI entirely, and directly check
  19  * whether the queried interface is in the interfaces list.
  20  */
  21
  22 #include "mozilla/dom/BindingDeclarations.h"
  23 #include "mozilla/dom/NonRefcountedDOMObject.h"
  24 #include "nsID.h"
  25
  26 namespace mozilla {
  27 class ErrorResult;
  28
  29 namespace dom {
  30
  31 class MozQueryInterface final : public NonRefcountedDOMObject {
  32  public:
  33   explicit MozQueryInterface(nsTArray<nsIID>&& aInterfaces)
  34       : mInterfaces(std::move(aInterfaces)) {}
  35
  36   bool QueriesTo(const nsIID& aIID) const;
  37
  38   void LegacyCall(JSContext* cx, JS::Handle<JS::Value> thisv,
  39                   JS::Handle<JS::Value> aIID,
  40                   JS::MutableHandle<JS::Value> aResult, ErrorResult& aRv) const;
  41
  42   nsISupports* GetParentObject() const { return nullptr; }
  43
  44   bool WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto,
  45                   JS::MutableHandle<JSObject*> aReflector);
  46
  47  private:
  48   nsTArray<nsIID> mInterfaces;
  49 };
  50
  51 }  // namespace dom
  52 }  // namespace mozilla
  53
  54 #endif  // mozilla_dom_MozQueryInterface