gecko-dev/xpcom/base/nsInterfaceRequestorAgg.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsInterfaceRequestorAgg.h"
#include "nsIInterfaceRequestor.h"
#include "nsCOMPtr.h"
#include "mozilla/Attributes.h"
#include "nsThreadUtils.h"
#include "nsProxyRelease.h"

class nsInterfaceRequestorAgg final : public nsIInterfaceRequestor {
 public:
  // XXX This needs to support threadsafe refcounting until we fix bug 243591.
  NS_DECL_THREADSAFE_ISUPPORTS
  NS_DECL_NSIINTERFACEREQUESTOR

  nsInterfaceRequestorAgg(nsIInterfaceRequestor* aFirst,
                          nsIInterfaceRequestor* aSecond,
                          nsIEventTarget* aConsumerTarget = nullptr)
      : mFirst(aFirst), mSecond(aSecond), mConsumerTarget(aConsumerTarget) {
    if (!mConsumerTarget) {
      mConsumerTarget = mozilla::GetCurrentSerialEventTarget();
    }
  }

 private:
  ~nsInterfaceRequestorAgg();

  nsCOMPtr<nsIInterfaceRequestor> mFirst, mSecond;
  nsCOMPtr<nsIEventTarget> mConsumerTarget;
};

NS_IMPL_ISUPPORTS(nsInterfaceRequestorAgg, nsIInterfaceRequestor)

NS_IMETHODIMP
nsInterfaceRequestorAgg::GetInterface(const nsIID& aIID, void** aResult) {
  nsresult rv = NS_ERROR_NO_INTERFACE;
  if (mFirst) {
    rv = mFirst->GetInterface(aIID, aResult);
  }
  if (mSecond && NS_FAILED(rv)) {
    rv = mSecond->GetInterface(aIID, aResult);
  }
  return rv;
}

nsInterfaceRequestorAgg::~nsInterfaceRequestorAgg() {
  NS_ProxyRelease("nsInterfaceRequestorAgg::mFirst", mConsumerTarget,
                  mFirst.forget());
  NS_ProxyRelease("nsInterfaceRequestorAgg::mSecond", mConsumerTarget,
                  mSecond.forget());
}

nsresult NS_NewInterfaceRequestorAggregation(nsIInterfaceRequestor* aFirst,
                                             nsIInterfaceRequestor* aSecond,
                                             nsIInterfaceRequestor** aResult) {
  *aResult = new nsInterfaceRequestorAgg(aFirst, aSecond);

  NS_ADDREF(*aResult);
  return NS_OK;
}

nsresult NS_NewInterfaceRequestorAggregation(nsIInterfaceRequestor* aFirst,
                                             nsIInterfaceRequestor* aSecond,
                                             nsIEventTarget* aTarget,
                                             nsIInterfaceRequestor** aResult) {
  *aResult = new nsInterfaceRequestorAgg(aFirst, aSecond, aTarget);

  NS_ADDREF(*aResult);
  return NS_OK;
}