1 files changed, 142 insertions, 0 deletions
diff --git a/ipc/mscom/oop/Factory.h b/ipc/mscom/oop/Factory.h
new file mode 100644
index 0000000000..e95f1d2499
--- /dev/null
+++ b/ipc/mscom/oop/Factory.h
@@ -0,0 +1,142 @@
+/* -*- 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_Factory_h
+#define mozilla_mscom_Factory_h
+
+#if defined(MOZILLA_INTERNAL_API)
+#  error This code is NOT for internal Gecko use!
+#endif  // defined(MOZILLA_INTERNAL_API)
+
+#include <objbase.h>
+#include <unknwn.h>
+
+#include <utility>
+
+#include "Module.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/DebugOnly.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/StaticPtr.h"
+
+/* WARNING! The code in this file may be loaded into the address spaces of other
+   processes! It MUST NOT link against xul.dll or other Gecko binaries! Only
+   inline code may be included! */
+
+namespace mozilla {
+namespace mscom {
+
+template <typename T>
+class MOZ_NONHEAP_CLASS Factory : public IClassFactory {
+  template <typename... Args>
+  HRESULT DoCreate(Args&&... args) {
+    MOZ_DIAGNOSTIC_ASSERT(false, "This should not be executed");
+    return E_NOTIMPL;
+  }
+
+  template <typename... Args>
+  HRESULT DoCreate(HRESULT (*aFnPtr)(IUnknown*, REFIID, void**),
+                   Args&&... args) {
+    return aFnPtr(std::forward<Args>(args)...);
+  }
+
+ public:
+  // IUnknown
+  STDMETHODIMP QueryInterface(REFIID aIid, void** aOutInterface) override {
+    if (!aOutInterface) {
+      return E_INVALIDARG;
+    }
+
+    if (aIid == IID_IUnknown || aIid == IID_IClassFactory) {
+      RefPtr<IClassFactory> punk(this);
+      punk.forget(aOutInterface);
+      return S_OK;
+    }
+
+    *aOutInterface = nullptr;
+
+    return E_NOINTERFACE;
+  }
+
+  STDMETHODIMP_(ULONG) AddRef() override {
+    Module::Lock();
+    return 2;
+  }
+
+  STDMETHODIMP_(ULONG) Release() override {
+    Module::Unlock();
+    return 1;
+  }
+
+  // IClassFactory
+  STDMETHODIMP CreateInstance(IUnknown* aOuter, REFIID aIid,
+                              void** aOutInterface) override {
+    return DoCreate(&T::Create, aOuter, aIid, aOutInterface);
+  }
+
+  STDMETHODIMP LockServer(BOOL aLock) override {
+    if (aLock) {
+      Module::Lock();
+    } else {
+      Module::Unlock();
+    }
+    return S_OK;
+  }
+};
+
+template <typename T>
+class MOZ_NONHEAP_CLASS SingletonFactory : public Factory<T> {
+ public:
+  STDMETHODIMP CreateInstance(IUnknown* aOuter, REFIID aIid,
+                              void** aOutInterface) override {
+    if (aOuter || !aOutInterface) {
+      return E_INVALIDARG;
+    }
+
+    RefPtr<T> obj(sInstance);
+    if (!obj) {
+      obj = GetOrCreateSingleton();
+    }
+
+    return obj->QueryInterface(aIid, aOutInterface);
+  }
+
+  RefPtr<T> GetOrCreateSingleton() {
+    if (!sInstance) {
+      RefPtr<T> object;
+      if (FAILED(T::Create(getter_AddRefs(object)))) {
+        return nullptr;
+      }
+
+      sInstance = object.forget();
+    }
+
+    return sInstance;
+  }
+
+  RefPtr<T> GetSingleton() { return sInstance; }
+
+  void ClearSingleton() {
+    if (!sInstance) {
+      return;
+    }
+
+    DebugOnly<HRESULT> hr = ::CoDisconnectObject(sInstance.get(), 0);
+    MOZ_ASSERT(SUCCEEDED(hr));
+    sInstance = nullptr;
+  }
+
+ private:
+  static StaticRefPtr<T> sInstance;
+};
+
+template <typename T>
+StaticRefPtr<T> SingletonFactory<T>::sInstance;
+
+}  // namespace mscom
+}  // namespace mozilla
+
+#endif  // mozilla_mscom_Factory_h