gecko-dev/mozglue/misc/DynamicallyLinkedFunctionPtr.h

74 строки
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_DynamicallyLinkedFunctionPtr_h
#define mozilla_DynamicallyLinkedFunctionPtr_h
#include "mozilla/Move.h"
#include <windows.h>
namespace mozilla {
template <typename T>
class DynamicallyLinkedFunctionPtr;
template <typename R, typename... Args>
class DynamicallyLinkedFunctionPtr<R (__stdcall*)(Args...)>
{
typedef R (__stdcall* FunctionPtrT)(Args...);
public:
DynamicallyLinkedFunctionPtr(const wchar_t* aLibName, const char* aFuncName)
: mModule(NULL)
, mFunction(nullptr)
{
mModule = ::LoadLibraryW(aLibName);
if (mModule) {
mFunction = reinterpret_cast<FunctionPtrT>(
::GetProcAddress(mModule, aFuncName));
if (!mFunction) {
// Since the function doesn't exist, there is no point in holding a
// reference to mModule anymore.
::FreeLibrary(mModule);
mModule = NULL;
}
}
}
DynamicallyLinkedFunctionPtr(const DynamicallyLinkedFunctionPtr&) = delete;
DynamicallyLinkedFunctionPtr& operator=(const DynamicallyLinkedFunctionPtr&) = delete;
DynamicallyLinkedFunctionPtr(DynamicallyLinkedFunctionPtr&&) = delete;
DynamicallyLinkedFunctionPtr& operator=(DynamicallyLinkedFunctionPtr&&) = delete;
~DynamicallyLinkedFunctionPtr()
{
if (mModule) {
::FreeLibrary(mModule);
}
}
R operator()(Args... args) const
{
return mFunction(std::forward<Args>(args)...);
}
explicit operator bool() const
{
return !!mFunction;
}
private:
HMODULE mModule;
FunctionPtrT mFunction;
};
} // namespace mozilla
#endif // mozilla_DynamicallyLinkedFunctionPtr_h