audio_system_win32.hpp

// Copyright Take Vos 2020-2022.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
 
#pragma once
 
#include "audio_system.hpp"
#include "audio_device_win32.hpp"
#include "../container/container.hpp"
#include "../memory/memory.hpp"
#include "../macros.hpp"
#include "../win32_headers.hpp"
#include <memory>
#include <coroutine>
 
hi_export_module(hikogui.audio.audio_system_win32);
 
hi_export namespace hi { inline namespace v1 {
class audio_system_win32;
 
hi_export struct audio_system_win32_event {
    virtual void handle_event(audio_system_win32 *self) noexcept = 0;
};
 
hi_export class audio_system_win32 : public audio_system {
public:
    using super = audio_system;
 
    audio_system_win32() : super(), _notification_client(std::make_unique<audio_system_win32_notification_client>(this))
    {
        hi_hresult_check(CoInitializeEx(NULL, COINIT_MULTITHREADED));
 
        hi_hresult_check(CoCreateInstance(
            __uuidof(MMDeviceEnumerator),
            NULL,
            CLSCTX_ALL,
            __uuidof(IMMDeviceEnumerator),
            reinterpret_cast<LPVOID *>(&_device_enumerator)));
        hi_assert(_device_enumerator);
 
        _device_enumerator->RegisterEndpointNotificationCallback(_notification_client.get());
 
        // Start with enumerating the devices.
        update_device_list();
    }
 
    virtual ~audio_system_win32()
    {
        if (_device_enumerator) {
            _device_enumerator->UnregisterEndpointNotificationCallback(_notification_client.get());
            _device_enumerator->Release();
        }
    }
 
    [[nodiscard]] generator<audio_device&> devices() noexcept override
    {
        for (auto const& device : _devices) {
            co_yield *device;
        }
    }
 
private:
    class audio_system_win32_notification_client : public IMMNotificationClient {
    public:
        virtual ~audio_system_win32_notification_client() = default;
 
        audio_system_win32_notification_client(audio_system_win32 *system) : IMMNotificationClient(), _system(system) {}
 
        STDMETHOD(OnDefaultDeviceChanged)(EDataFlow flow, ERole role, LPCWSTR device_id) override
        {
            loop::main().wfree_post_function([this]() {
                _system->update_device_list();
                _system->_notifier();
            });
            return S_OK;
        }
 
        STDMETHOD(OnDeviceAdded)(LPCWSTR device_id) override
        {
            loop::main().wfree_post_function([this]() {
                _system->update_device_list();
                _system->_notifier();
            });
            return S_OK;
        }
 
        STDMETHOD(OnDeviceRemoved)(LPCWSTR device_id) override
        {
            // OnDeviceRemoved can not be implemented according to the win32 specification due
            // to conflicting requirements.
            // 1. This function may not block.
            // 2. The string pointed by device_id will not exist after this function.
            // 2. We need to copy device_id which has an unbounded size.
            // 3. Allocating a string blocks.
 
            hi_assert_not_null(device_id);
            loop::main().wfree_post_function([this]() {
                _system->update_device_list();
                _system->_notifier();
            });
            return S_OK;
        }
 
        STDMETHOD(OnDeviceStateChanged)(LPCWSTR device_id, DWORD state) override
        {
            loop::main().wfree_post_function([this]() {
                _system->update_device_list();
                _system->_notifier();
            });
            return S_OK;
        }
 
        STDMETHOD(OnPropertyValueChanged)(LPCWSTR device_id, PROPERTYKEY const key) override
        {
            loop::main().wfree_post_function([this]() {
                _system->update_device_list();
                _system->_notifier();
            });
            return S_OK;
        }
 
        STDMETHOD(QueryInterface)(REFIID iid, void **object) override
        {
            hi_no_default();
        }
 
        STDMETHOD_(ULONG, AddRef)() override
        {
            hi_no_default();
        }
 
        STDMETHOD_(ULONG, Release)() override
        {
            hi_no_default();
        }
 
    private:
        audio_system_win32 *_system;
    };
 
    std::vector<std::shared_ptr<audio_device>> _devices;
 
    IMMDeviceEnumerator *_device_enumerator;
    std::unique_ptr<audio_system_win32_notification_client> _notification_client;
 
    void update_device_list() noexcept
    {
        hi_axiom(loop::main().on_thread());
        hi_log_info("Updating audio device list:");
 
        IMMDeviceCollection *device_collection;
        if (FAILED(_device_enumerator->EnumAudioEndpoints(
                eAll, DEVICE_STATE_ACTIVE | DEVICE_STATE_DISABLED | DEVICE_STATE_UNPLUGGED, &device_collection))) {
            hi_log_error("EnumAudioEndpoints() failed: {}", get_last_error_message());
            return;
        }
        hi_assert(device_collection);
 
        UINT number_of_devices;
        if (FAILED(device_collection->GetCount(&number_of_devices))) {
            hi_log_error("EnumAudioEndpoints()->GetCount() failed: {}", get_last_error_message());
            device_collection->Release();
            return;
        }
 
        auto old_devices = _devices;
        _devices.clear();
        for (UINT i = 0; i < number_of_devices; i++) {
            IMMDevice *win32_device;
            if (FAILED(device_collection->Item(i, &win32_device))) {
                hi_log_error("EnumAudioEndpoints()->Item({}) failed: {}", i, get_last_error_message());
                device_collection->Release();
                return;
            }
            hi_assert(win32_device);
 
            auto win32_device_id = std::string{};
            try {
                win32_device_id = std::string{"win32:"} + audio_device_win32::get_device_id(win32_device);
            } catch (std::exception const& e) {
                hi_log_error("EnumAudioEndpoints()->Item({})->get_device_id failed: {}", i, e.what());
                device_collection->Release();
                win32_device->Release();
                return;
            }
 
            auto it = std::find_if(old_devices.begin(), old_devices.end(), [&win32_device_id](auto& item) {
                return item->id() == win32_device_id;
            });
 
            if (it != old_devices.end()) {
                // This device was already instantiated.
                win32_device->Release();
                _devices.push_back(std::move(*it));
                old_devices.erase(it);
 
                // Let the audio device them self see if anything has changed in their own state.
                _devices.back()->update_state();
 
            } else {
                auto device =
                    std::allocate_shared<audio_device_win32>(locked_memory_allocator<audio_device_win32>{}, win32_device);
                // hi_log_info(
                //    "Found audio device \"{}\", state={}, channels={}, speakers={}",
                //    device->name(),
                //    device->state(),
                //    device->full_num_channels(),
                //    device->full_channel_mapping());
                _devices.push_back(std::move(device));
            }
        }
 
        device_collection->Release();
    }
 
    friend class audio_system_win32_notification_client;
};
 
hi_export [[nodiscard]] inline audio_system &audio_system::global() noexcept
{
    if (not detail::audio_system_global) {
        auto tmp = std::make_unique<audio_system_aggregate>();
        tmp->add_child(std::make_unique<audio_system_win32>());
        // Possibly add asio here as well.
 
        detail::audio_system_global = std::move(tmp);
    }
    return *detail::audio_system_global;
}
 
}} // namespace hi::inline v1