gecko-dev/ipc/mscom/AgileReference.cpp

153 строки
4.0 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/. */
#include "mozilla/mscom/AgileReference.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/DynamicallyLinkedFunctionPtr.h"
#include "mozilla/Assertions.h"
#include "mozilla/Move.h"
#if NTDDI_VERSION < NTDDI_WINBLUE
// Declarations from Windows SDK specific to Windows 8.1
enum AgileReferenceOptions
{
AGILEREFERENCE_DEFAULT = 0,
AGILEREFERENCE_DELAYEDMARSHAL = 1,
};
HRESULT WINAPI RoGetAgileReference(AgileReferenceOptions options,
REFIID riid, IUnknown* pUnk,
IAgileReference** ppAgileReference);
#endif // NTDDI_VERSION < NTDDI_WINBLUE
namespace mozilla {
namespace mscom {
AgileReference::AgileReference(REFIID aIid, IUnknown* aObject)
: mIid(aIid)
, mGitCookie(0)
{
/*
* There are two possible techniques for creating agile references. Starting
* with Windows 8.1, we may use the RoGetAgileReference API, which is faster.
* If that API is not available, we fall back to using the Global Interface
* Table.
*/
static const DynamicallyLinkedFunctionPtr<decltype(&::RoGetAgileReference)>
pRoGetAgileReference(L"ole32.dll", "RoGetAgileReference");
MOZ_ASSERT(aObject);
if (pRoGetAgileReference &&
SUCCEEDED(pRoGetAgileReference(AGILEREFERENCE_DEFAULT, aIid, aObject,
getter_AddRefs(mAgileRef)))) {
return;
}
IGlobalInterfaceTable* git = ObtainGit();
MOZ_ASSERT(git);
if (!git) {
return;
}
DebugOnly<HRESULT> hr = git->RegisterInterfaceInGlobal(aObject, aIid,
&mGitCookie);
MOZ_ASSERT(SUCCEEDED(hr));
}
AgileReference::AgileReference(AgileReference&& aOther)
: mIid(aOther.mIid)
, mAgileRef(std::move(aOther.mAgileRef))
, mGitCookie(aOther.mGitCookie)
{
aOther.mGitCookie = 0;
}
AgileReference::~AgileReference()
{
if (!mGitCookie) {
return;
}
IGlobalInterfaceTable* git = ObtainGit();
MOZ_ASSERT(git);
if (!git) {
return;
}
DebugOnly<HRESULT> hr = git->RevokeInterfaceFromGlobal(mGitCookie);
MOZ_ASSERT(SUCCEEDED(hr));
}
HRESULT
AgileReference::Resolve(REFIID aIid, void** aOutInterface)
{
MOZ_ASSERT(aOutInterface);
MOZ_ASSERT(mAgileRef || mGitCookie);
if (!aOutInterface) {
return E_INVALIDARG;
}
*aOutInterface = nullptr;
if (mAgileRef) {
// IAgileReference lets you directly resolve the interface you want...
return mAgileRef->Resolve(aIid, aOutInterface);
}
if (!mGitCookie) {
return E_UNEXPECTED;
}
IGlobalInterfaceTable* git = ObtainGit();
MOZ_ASSERT(git);
if (!git) {
return E_UNEXPECTED;
}
RefPtr<IUnknown> originalInterface;
HRESULT hr = git->GetInterfaceFromGlobal(mGitCookie, mIid,
getter_AddRefs(originalInterface));
if (FAILED(hr)) {
return hr;
}
if (aIid == mIid) {
originalInterface.forget(aOutInterface);
return S_OK;
}
// ...Whereas the GIT requires us to obtain the same interface that we
// requested and then QI for the desired interface afterward.
return originalInterface->QueryInterface(aIid, aOutInterface);
}
IGlobalInterfaceTable*
AgileReference::ObtainGit()
{
// Internally to COM, the Global Interface Table is a singleton, therefore we
// don't worry about holding onto this reference indefinitely.
static IGlobalInterfaceTable* sGit = []() -> IGlobalInterfaceTable* {
IGlobalInterfaceTable* result = nullptr;
DebugOnly<HRESULT> hr =
::CoCreateInstance(CLSID_StdGlobalInterfaceTable, nullptr,
CLSCTX_INPROC_SERVER, IID_IGlobalInterfaceTable,
reinterpret_cast<void**>(&result));
MOZ_ASSERT(SUCCEEDED(hr));
return result;
}();
return sGit;
}
} // namespace mscom
} // namespace mozilla