gecko-dev/ipc/mscom/AgileReference.h
Aaron Klotz 74cac7296d Bug 1338596: Add support for agile references to mscom; r=jimm
MozReview-Commit-ID: 1NZoFZntO3g

--HG--
extra : rebase_source : 6d3ed1da4893747d38c1bd2c31671d8ecf535cfd
2017-02-10 11:18:26 -07:00

68 lines
1.9 KiB
C++

/* -*- 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/. */
#ifndef mozilla_mscom_AgileReference_h
#define mozilla_mscom_AgileReference_h
#include "mozilla/RefPtr.h"
#include <objidl.h>
namespace mozilla {
namespace mscom {
/**
* This class encapsulates an "agile reference." These are references that
* allow you to pass COM interfaces between apartments. When you have an
* interface that you would like to pass between apartments, you wrap that
* interface in an AgileReference and pass the agile reference instead. Then
* you unwrap the interface by calling AgileReference::Resolve.
*
* Sample usage:
*
* // In the multithreaded apartment, foo is an IFoo*
* auto myAgileRef = MakeUnique<AgileReference>(IID_IFoo, foo);
*
* // myAgileRef is passed to our main thread, which runs in a single-threaded
* // apartment:
*
* RefPtr<IFoo> foo;
* HRESULT hr = myAgileRef->Resolve(IID_IFoo, getter_AddRefs(foo));
* // Now foo may be called from the main thread
*/
class AgileReference
{
public:
AgileReference(REFIID aIid, IUnknown* aObject);
AgileReference(AgileReference&& aOther);
~AgileReference();
explicit operator bool() const
{
return mAgileRef || mGitCookie;
}
HRESULT Resolve(REFIID aIid, void** aOutInterface);
AgileReference(const AgileReference& aOther) = delete;
AgileReference& operator=(const AgileReference& aOther) = delete;
AgileReference& operator=(AgileReference&& aOther) = delete;
private:
IGlobalInterfaceTable* ObtainGit();
private:
REFIID mIid;
RefPtr<IAgileReference> mAgileRef;
DWORD mGitCookie;
};
} // namespace mscom
} // namespace mozilla
#endif // mozilla_mscom_AgileReference_h