From 33dbfa328104c591e8daf06f4ab7cd041fa0e655 Mon Sep 17 00:00:00 2001
From: Timothy Flynn <trflynn89@pm.me>
Date: Wed, 21 Jun 2023 10:16:42 -0400
Subject: [PATCH] Ladybird: Detect changes to the default audio device

When the default audio device changes on the host, it's convenient to
automatically switch to that device rather than needing to reload the
page to update.
---
 Ladybird/AudioCodecPluginLadybird.cpp | 61 ++++++++++++++++++++++++---
 1 file changed, 55 insertions(+), 6 deletions(-)

diff --git a/Ladybird/AudioCodecPluginLadybird.cpp b/Ladybird/AudioCodecPluginLadybird.cpp
index 534dd4d2c1..eab2e9624e 100644
--- a/Ladybird/AudioCodecPluginLadybird.cpp
+++ b/Ladybird/AudioCodecPluginLadybird.cpp
@@ -27,6 +27,7 @@ struct AudioTask {
         Pause,
         Seek,
         Volume,
+        RecreateAudioDevice,
     };
 
     Type type;
@@ -82,20 +83,64 @@ private:
         No,
     };
 
+    struct AudioDevice {
+        static AudioDevice create()
+        {
+            auto const& device_info = QMediaDevices::defaultAudioOutput();
+
+            auto format = device_info.preferredFormat();
+            format.setChannelCount(2);
+
+            auto audio_output = make<QAudioSink>(device_info, format);
+            return AudioDevice { move(audio_output) };
+        }
+
+        AudioDevice(AudioDevice&&) = default;
+
+        AudioDevice& operator=(AudioDevice&& device)
+        {
+            if (audio_output) {
+                audio_output->stop();
+                io_device = nullptr;
+            }
+
+            swap(audio_output, device.audio_output);
+            swap(io_device, device.io_device);
+            return *this;
+        }
+
+        ~AudioDevice()
+        {
+            if (audio_output)
+                audio_output->stop();
+        }
+
+        OwnPtr<QAudioSink> audio_output;
+        QIODevice* io_device { nullptr };
+
+    private:
+        explicit AudioDevice(NonnullOwnPtr<QAudioSink> output)
+            : audio_output(move(output))
+        {
+            io_device = audio_output->start();
+        }
+    };
+
     void run() override
     {
         auto devices = make<QMediaDevices>();
-        auto const& device_info = devices->defaultAudioOutput();
+        auto audio_device = AudioDevice::create();
 
-        auto format = device_info.preferredFormat();
-        format.setChannelCount(2);
-
-        auto audio_output = make<QAudioSink>(device_info, format);
-        auto* io_device = audio_output->start();
+        connect(devices, &QMediaDevices::audioOutputsChanged, this, [this]() {
+            queue_task({ AudioTask::Type::RecreateAudioDevice }).release_value_but_fixme_should_propagate_errors();
+        });
 
         auto paused = Paused::Yes;
 
         while (true) {
+            auto& audio_output = audio_device.audio_output;
+            auto* io_device = audio_device.io_device;
+
             if (auto result = m_task_queue.dequeue(); result.is_error()) {
                 VERIFY(result.error() == AudioTaskQueue::QueueStatus::Empty);
             } else {
@@ -136,6 +181,10 @@ private:
                     VERIFY(task.data.has_value());
                     audio_output->setVolume(*task.data);
                     break;
+
+                case AudioTask::Type::RecreateAudioDevice:
+                    audio_device = AudioDevice::create();
+                    continue;
                 }
             }