gitadora: (arena model) simulate Realtek device, fix asio redirect hooks (#732)

## Link to GitHub Issue or related Pull Request, if one exists
#730, #718

## Description of change

Part 1)

When ASIO is in use, the game also looks for a Realtek device so that it
can open a WASAPI Exclusive mode stream for headphones.

Add an option to fake that, in case the user doesn't have a Realtek
device.

Part 2)

`-gdaasio` wasn't workign properly - fix the logic.

## Testing
Seems to work with FlexASIO, and Xonar with no real Realtek device.

src/spice2x/hooks/audio/backends/mmdevice/null_device.cpp

@@ -0,0 +1,195 @@
+#include "null_device.h"
+
+#include <atomic>
+#include <cstring>
+
+#include <audioclient.h>
+
+#include "hooks/audio/audio.h"
+#include "hooks/audio/audio_private.h"
+#include "hooks/audio/backends/wasapi/dummy_audio_client.h"
+#include "util/logging.h"
+#include "util/utils.h"
+
+#include "null_discard_backend.h"
+
+// friendly name reported by the synthetic device. must contain "Realtek" so the
+// gitadora arena device search matches it.
+static const wchar_t NULL_DEVICE_FRIENDLY_NAME[] = L"Realtek High Definition Audio";
+
+// arbitrary identifier reported by the synthetic device.
+static const wchar_t NULL_DEVICE_ID[] = L"{spice2x-null-render-device}";
+
+// PKEY_Device_FriendlyName, hardcoded to avoid pulling in functiondiscoverykeys_devpkey.h
+static const PROPERTYKEY PKEY_DEVICE_FRIENDLY_NAME_LOCAL = {
+    { 0xa45c254e, 0xdf1c, 0x4efd, { 0x80, 0x20, 0x67, 0xd1, 0x46, 0xa8, 0x50, 0xe0 } },
+    14
+};
+
+bool null_render_device_enabled() {
+    return hooks::audio::FAKE_REALTEK_RENDER_DEVICE;
+}
+
+// duplicate a wide string into CoTaskMem so the caller can free it with
+// CoTaskMemFree / PropVariantClear as the COM API contract requires.
+static LPWSTR co_task_wcsdup(const wchar_t *src) {
+    const size_t bytes = (wcslen(src) + 1) * sizeof(wchar_t);
+    auto *dst = static_cast<LPWSTR>(CoTaskMemAlloc(bytes));
+    if (dst != nullptr) {
+        memcpy(dst, src, bytes);
+    }
+    return dst;
+}
+
+namespace {
+
+    // minimal IPropertyStore that only answers PKEY_Device_FriendlyName.
+    struct NullPropertyStore : IPropertyStore {
+        std::atomic<ULONG> ref_cnt = 1;
+
+        virtual ~NullPropertyStore() = default;
+
+        HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, void **ppvObj) override {
+            if (ppvObj == nullptr) {
+                return E_POINTER;
+            }
+            if (riid == __uuidof(IUnknown) || riid == __uuidof(IPropertyStore)) {
+                this->AddRef();
+                *ppvObj = this;
+                return S_OK;
+            }
+            *ppvObj = nullptr;
+            return E_NOINTERFACE;
+        }
+        ULONG STDMETHODCALLTYPE AddRef() override {
+            return ++this->ref_cnt;
+        }
+        ULONG STDMETHODCALLTYPE Release() override {
+            const ULONG refs = --this->ref_cnt;
+            if (refs == 0) {
+                delete this;
+            }
+            return refs;
+        }
+        HRESULT STDMETHODCALLTYPE GetCount(DWORD *cProps) override {
+            if (cProps == nullptr) {
+                return E_POINTER;
+            }
+            *cProps = 1;
+            return S_OK;
+        }
+        HRESULT STDMETHODCALLTYPE GetAt(DWORD iProp, PROPERTYKEY *pkey) override {
+            if (pkey == nullptr) {
+                return E_POINTER;
+            }
+            if (iProp != 0) {
+                return E_INVALIDARG;
+            }
+            *pkey = PKEY_DEVICE_FRIENDLY_NAME_LOCAL;
+            return S_OK;
+        }
+        HRESULT STDMETHODCALLTYPE GetValue(REFPROPERTYKEY key, PROPVARIANT *pv) override {
+            if (pv == nullptr) {
+                return E_POINTER;
+            }
+            PropVariantInit(pv);
+            if (key.fmtid == PKEY_DEVICE_FRIENDLY_NAME_LOCAL.fmtid
+                    && key.pid == PKEY_DEVICE_FRIENDLY_NAME_LOCAL.pid) {
+                pv->pwszVal = co_task_wcsdup(NULL_DEVICE_FRIENDLY_NAME);
+                if (pv->pwszVal == nullptr) {
+                    return E_OUTOFMEMORY;
+                }
+                pv->vt = VT_LPWSTR;
+            }
+            // unknown keys are returned as VT_EMPTY / S_OK
+            return S_OK;
+        }
+        HRESULT STDMETHODCALLTYPE SetValue(REFPROPERTYKEY, REFPROPVARIANT) override {
+            return STG_E_ACCESSDENIED;
+        }
+        HRESULT STDMETHODCALLTYPE Commit() override {
+            return S_OK;
+        }
+    };
+}
+
+#pragma region IUnknown
+HRESULT STDMETHODCALLTYPE NullMMDevice::QueryInterface(REFIID riid, void **ppvObj) {
+    if (ppvObj == nullptr) {
+        return E_POINTER;
+    }
+    if (riid == __uuidof(IUnknown) || riid == __uuidof(IMMDevice)) {
+        this->AddRef();
+        *ppvObj = this;
+        return S_OK;
+    }
+    *ppvObj = nullptr;
+    return E_NOINTERFACE;
+}
+ULONG STDMETHODCALLTYPE NullMMDevice::AddRef() {
+    return ++this->ref_cnt;
+}
+ULONG STDMETHODCALLTYPE NullMMDevice::Release() {
+    const ULONG refs = --this->ref_cnt;
+    if (refs == 0) {
+        delete this;
+    }
+    return refs;
+}
+#pragma endregion
+
+#pragma region IMMDevice
+HRESULT STDMETHODCALLTYPE NullMMDevice::Activate(
+    REFIID iid,
+    DWORD,
+    PROPVARIANT *,
+    void **ppInterface)
+{
+    if (ppInterface == nullptr) {
+        return E_POINTER;
+    }
+    *ppInterface = nullptr;
+
+    log_info("audio::null", "NullMMDevice::Activate {}", guid2s(iid));
+
+    if (iid == IID_IAudioClient) {
+
+        // release any previously persisted client
+        if (hooks::audio::CLIENT != nullptr) {
+            hooks::audio::CLIENT->Release();
+        }
+
+        auto *client = static_cast<IAudioClient *>(new DummyIAudioClient(new NullDiscardBackend()));
+        *ppInterface = client;
+
+        // persist the audio client
+        hooks::audio::CLIENT = client;
+        hooks::audio::CLIENT->AddRef();
+
+        return S_OK;
+    }
+
+    return E_NOINTERFACE;
+}
+HRESULT STDMETHODCALLTYPE NullMMDevice::OpenPropertyStore(DWORD, IPropertyStore **ppProperties) {
+    if (ppProperties == nullptr) {
+        return E_POINTER;
+    }
+    *ppProperties = new NullPropertyStore();
+    return S_OK;
+}
+HRESULT STDMETHODCALLTYPE NullMMDevice::GetId(LPWSTR *ppstrId) {
+    if (ppstrId == nullptr) {
+        return E_POINTER;
+    }
+    *ppstrId = co_task_wcsdup(NULL_DEVICE_ID);
+    return *ppstrId != nullptr ? S_OK : E_OUTOFMEMORY;
+}
+HRESULT STDMETHODCALLTYPE NullMMDevice::GetState(DWORD *pdwState) {
+    if (pdwState == nullptr) {
+        return E_POINTER;
+    }
+    *pdwState = DEVICE_STATE_ACTIVE;
+    return S_OK;
+}
+#pragma endregion