TestHelloXPLoop.cpp

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * 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 "nsIServiceManager.h"
#include "nsCOMPtr.h"
#include "nsCNativeApp.h"
#include "nsIEventLoop.h"
#include <windows.h>

static NS_DEFINE_CID(kNativeAppCID, NS_NATIVE_APP_CID);

LRESULT CALLBACK WndProc(HWND wnd, UINT msg, WPARAM wParam, LPARAM lParam);

void ErrorBox(LPSTR text) {
  MessageBox(nullptr, text, "XP Event Loop", MB_OK | MB_ICONSTOP);
}

void InfoBox(LPSTR text) {
  MessageBox(nullptr, text, "XP Event Loop", MB_OK | MB_ICONINFORMATION);
}

int WINAPI WinMain(HINSTANCE inst, HINSTANCE prevInstance, LPSTR lpszCmdLine,
                   int nShowCmd) {
  char* lpszAppName = "HelloWorld";
  HWND wnd;
  WNDCLASSEX wndclass;
  int retCode;

  {  //  Needed to scope all nsCOMPtr within XPCOM Init and Shutdown
    nsresult rv;
    nsCOMPtr<nsIServiceManager> servMan;
    rv = NS_InitXPCOM2(getter_AddRefs(servMan), nullptr, nullptr);
    if (NS_FAILED(rv)) {
      ErrorBox("Failed to initialize xpcom.");
      return -1;
    }

    nsCOMPtr<nsIComponentRegistrar> registrar = do_QueryInterface(servMan);
    NS_ASSERTION(registrar, "Null nsIComponentRegistrar");
    registrar->AutoRegister(nullptr);

    nsCOMPtr<nsINativeApp> nativeAppService(do_GetService(kNativeAppCID, &rv));

    if (NS_FAILED(rv)) {
      ErrorBox("Failed to get nativeAppService");
      return -1;
    }
    wndclass.cbSize = sizeof(wndclass);
    wndclass.style = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc = WndProc;
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hInstance = inst;
    wndclass.hIcon = LoadIcon(nullptr, IDI_APPLICATION);
    wndclass.hCursor = LoadCursor(nullptr, IDC_ARROW);
    wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wndclass.lpszMenuName = nullptr;
    wndclass.lpszClassName = lpszAppName;
    wndclass.hIconSm = LoadIcon(nullptr, IDI_APPLICATION);

    RegisterClassEx(&wndclass);

    wnd = CreateWindow(lpszAppName, "The Hello World", WS_OVERLAPPEDWINDOW,
                       CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,
                       CW_USEDEFAULT, nullptr, nullptr, inst, nullptr);

    ShowWindow(wnd, nShowCmd);
    UpdateWindow(wnd);

    nsCOMPtr<nsIEventLoop> eventLoop;

    if (NS_FAILED(nativeAppService->CreateEventLoop(
            L"_MainLoop", nsEventLoopTypes::MainAppLoop,
            getter_AddRefs(eventLoop)))) {
      ErrorBox("Failed to create event Loop");
      return 0;
    }

    eventLoop->Run(nullptr, nullptr, nullptr, &retCode);
    eventLoop = nullptr;  // Clear out before Shutting down XPCOM

    InfoBox("Hello World app is out of loop");
  }
  NS_ShutdownXPCOM(nullptr);
  InfoBox("Hello World app is exiting");
  return retCode;
}

LRESULT CALLBACK WndProc(HWND wnd, UINT msg, WPARAM wParam, LPARAM lParam) {
  HDC hdc;
  PAINTSTRUCT ps;
  RECT rect;

  switch (msg) {
    case WM_PAINT:
      hdc = BeginPaint(wnd, &ps);

      GetClientRect(wnd, &rect);

      DrawText(hdc, "Hello, XP Event Loop!", -1, &rect,
               DT_SINGLELINE | DT_CENTER | DT_VCENTER);

      EndPaint(wnd, &ps);
      return 0;

    case WM_DESTROY: {
      nsresult rv;
      nsCOMPtr<nsINativeApp> nativeAppService =
          do_GetService(kNativeAppCID, &rv);
      if (NS_FAILED(rv)) {
        ErrorBox("Could not get NativeAppService");
        return 0;
      }
      nsCOMPtr<nsIEventLoop> eventLoop;

      if (NS_FAILED(nativeAppService->FindEventLoop(
              L"_MainLoop", getter_AddRefs(eventLoop)))) {
        ErrorBox("Failed to find event Loop");
        return 0;
      }
      eventLoop->Exit(0);
    }
      return 0;
  }

  return DefWindowProc(wnd, msg, wParam, lParam);
}