idzio/wnd.c: Add helper for message window creation

idzio/meson.build

@@ -14,6 +14,8 @@ idzio_dll = shared_library(
         'idzio.h',
         'shifter.c',
         'shifter.h',
+        'wnd.c',
+        'wnd.h',
         'xi.c',
         'xi.h',
     ],

idzio/wnd.c

@@ -0,0 +1,86 @@
+#include <windows.h>
+
+#include <assert.h>
+#include <string.h>
+
+#include "util/dprintf.h"
+
+/* DirectInput requires a window for correct initialization (and also force
+   feedback), so this source file provides some utilities for creating a
+   generic message-only window. */
+
+static LRESULT WINAPI idz_io_wnd_proc(
+            HWND hwnd,
+            UINT msg,
+            WPARAM wparam,
+            LPARAM lparam);
+
+HRESULT idz_io_wnd_create(HINSTANCE inst, HWND *out)
+{
+    HRESULT hr;
+    WNDCLASSEXW wcx;
+    ATOM atom;
+    HWND hwnd;
+
+    assert(inst != NULL); /* We are not an EXE */
+    assert(out != NULL);
+
+    *out = NULL;
+
+    memset(&wcx, 0, sizeof(wcx));
+    wcx.cbSize = sizeof(wcx);
+    wcx.lpfnWndProc = idz_io_wnd_proc;
+    wcx.hInstance = inst;
+    wcx.lpszClassName = L"IDZIO";
+
+    atom = RegisterClassExW(&wcx);
+
+    if (atom == 0) {
+        hr = HRESULT_FROM_WIN32(GetLastError());
+        dprintf("IDZIO: RegisterClassExW failed: %08x\n", (int) hr);
+
+        goto fail;
+    }
+
+    hwnd = CreateWindowExW(
+            0,
+            (wchar_t *) (intptr_t) atom,
+            L"",
+            0,
+            CW_USEDEFAULT,
+            CW_USEDEFAULT,
+            CW_USEDEFAULT,
+            CW_USEDEFAULT,
+            HWND_MESSAGE,
+            NULL,
+            inst,
+            NULL);
+
+    if (hwnd == NULL) {
+        hr = HRESULT_FROM_WIN32(GetLastError());
+        dprintf("IDZIO: CreateWindowExW failed: %08x\n", (int) hr);
+
+        goto fail;
+    }
+
+    *out = hwnd;
+
+    return S_OK;
+
+fail:
+    UnregisterClassW((wchar_t *) (intptr_t) atom, inst);
+
+    return hr;
+}
+
+static LRESULT WINAPI idz_io_wnd_proc(
+            HWND hwnd,
+            UINT msg,
+            WPARAM wparam,
+            LPARAM lparam)
+{
+    switch (msg) {
+    default:
+        return DefWindowProcW(hwnd, msg, wparam, lparam);
+    }
+}

idzio/wnd.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#include <windows.h>
+
+HRESULT idz_io_wnd_create(HINSTANCE inst, HWND *out);