1 files changed, 156 insertions, 0 deletions
diff --git a/ipc/mscom/DispatchForwarder.cpp b/ipc/mscom/DispatchForwarder.cpp
new file mode 100644
index 0000000000..e55b1316d0
--- /dev/null
+++ b/ipc/mscom/DispatchForwarder.cpp
@@ -0,0 +1,156 @@
+/* -*- 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/DispatchForwarder.h"
+
+#include <oleauto.h>
+
+#include <utility>
+
+#include "mozilla/mscom/MainThreadInvoker.h"
+
+namespace mozilla {
+namespace mscom {
+
+/* static */
+HRESULT DispatchForwarder::Create(IInterceptor* aInterceptor,
+                                  STAUniquePtr<IDispatch>& aTarget,
+                                  IUnknown** aOutput) {
+  MOZ_ASSERT(aInterceptor && aOutput);
+  if (!aOutput) {
+    return E_INVALIDARG;
+  }
+  *aOutput = nullptr;
+  if (!aInterceptor) {
+    return E_INVALIDARG;
+  }
+  DispatchForwarder* forwarder = new DispatchForwarder(aInterceptor, aTarget);
+  HRESULT hr = forwarder->QueryInterface(IID_IDispatch, (void**)aOutput);
+  forwarder->Release();
+  return hr;
+}
+
+DispatchForwarder::DispatchForwarder(IInterceptor* aInterceptor,
+                                     STAUniquePtr<IDispatch>& aTarget)
+    : mRefCnt(1), mInterceptor(aInterceptor), mTarget(std::move(aTarget)) {}
+
+DispatchForwarder::~DispatchForwarder() {}
+
+HRESULT
+DispatchForwarder::QueryInterface(REFIID riid, void** ppv) {
+  if (!ppv) {
+    return E_INVALIDARG;
+  }
+
+  // Since this class implements a tearoff, any interfaces that are not
+  // IDispatch must be routed to the original object's QueryInterface.
+  // This is especially important for IUnknown since COM uses that interface
+  // to determine object identity.
+  if (riid != IID_IDispatch) {
+    return mInterceptor->QueryInterface(riid, ppv);
+  }
+
+  IUnknown* punk = static_cast<IDispatch*>(this);
+  *ppv = punk;
+  if (!punk) {
+    return E_NOINTERFACE;
+  }
+
+  punk->AddRef();
+  return S_OK;
+}
+
+ULONG
+DispatchForwarder::AddRef() {
+  return (ULONG)InterlockedIncrement((LONG*)&mRefCnt);
+}
+
+ULONG
+DispatchForwarder::Release() {
+  ULONG newRefCnt = (ULONG)InterlockedDecrement((LONG*)&mRefCnt);
+  if (newRefCnt == 0) {
+    delete this;
+  }
+  return newRefCnt;
+}
+
+HRESULT
+DispatchForwarder::GetTypeInfoCount(UINT* pctinfo) {
+  if (!pctinfo) {
+    return E_INVALIDARG;
+  }
+  *pctinfo = 1;
+  return S_OK;
+}
+
+HRESULT
+DispatchForwarder::GetTypeInfo(UINT iTInfo, LCID lcid, ITypeInfo** ppTInfo) {
+  // ITypeInfo as implemented by COM is apartment-neutral, so we don't need
+  // to wrap it (yay!)
+  if (mTypeInfo) {
+    RefPtr<ITypeInfo> copy(mTypeInfo);
+    copy.forget(ppTInfo);
+    return S_OK;
+  }
+  HRESULT hr = E_UNEXPECTED;
+  auto fn = [&]() -> void { hr = mTarget->GetTypeInfo(iTInfo, lcid, ppTInfo); };
+  MainThreadInvoker invoker;
+  if (!invoker.Invoke(
+          NS_NewRunnableFunction("DispatchForwarder::GetTypeInfo", fn))) {
+    return E_UNEXPECTED;
+  }
+  if (FAILED(hr)) {
+    return hr;
+  }
+  mTypeInfo = *ppTInfo;
+  return hr;
+}
+
+HRESULT
+DispatchForwarder::GetIDsOfNames(REFIID riid, LPOLESTR* rgszNames, UINT cNames,
+                                 LCID lcid, DISPID* rgDispId) {
+  HRESULT hr = E_UNEXPECTED;
+  auto fn = [&]() -> void {
+    hr = mTarget->GetIDsOfNames(riid, rgszNames, cNames, lcid, rgDispId);
+  };
+  MainThreadInvoker invoker;
+  if (!invoker.Invoke(
+          NS_NewRunnableFunction("DispatchForwarder::GetIDsOfNames", fn))) {
+    return E_UNEXPECTED;
+  }
+  return hr;
+}
+
+HRESULT
+DispatchForwarder::Invoke(DISPID dispIdMember, REFIID riid, LCID lcid,
+                          WORD wFlags, DISPPARAMS* pDispParams,
+                          VARIANT* pVarResult, EXCEPINFO* pExcepInfo,
+                          UINT* puArgErr) {
+  HRESULT hr;
+  if (!mInterface) {
+    if (!mTypeInfo) {
+      return E_UNEXPECTED;
+    }
+    TYPEATTR* typeAttr = nullptr;
+    hr = mTypeInfo->GetTypeAttr(&typeAttr);
+    if (FAILED(hr)) {
+      return hr;
+    }
+    hr = mInterceptor->QueryInterface(typeAttr->guid,
+                                      (void**)getter_AddRefs(mInterface));
+    mTypeInfo->ReleaseTypeAttr(typeAttr);
+    if (FAILED(hr)) {
+      return hr;
+    }
+  }
+  // We don't invoke IDispatch on the target, but rather on the interceptor!
+  hr = ::DispInvoke(mInterface.get(), mTypeInfo, dispIdMember, wFlags,
+                    pDispParams, pVarResult, pExcepInfo, puArgErr);
+  return hr;
+}
+
+}  // namespace mscom
+}  // namespace mozilla