48 lines
2.2 KiB
C#
48 lines
2.2 KiB
C#
 
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using NAudio.CoreAudioApi;
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using NAudio.CoreAudioApi.Interfaces;
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namespace RemSound.App;
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/// <summary>
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/// Fires a callback whenever the set of Windows audio endpoints changes — a device is added,
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/// removed, changes state (plugged / unplugged / enabled / disabled), or the default device
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/// changes. This replaces the pre-v3.4 3-second polling of the device lists: instead of
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/// re-enumerating every tick whether or not anything changed, RemSound re-reads the device lists
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/// only when Windows actually tells us the device set changed.
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///
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/// The callbacks arrive on a COM thread, so the consumer (<see cref="MainForm"/>) marshals to the
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/// UI thread and debounces — a single hot-plug typically fires several of these in quick
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/// succession (state-changed + added + default-changed), which collapse into one refresh.
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///
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/// Property-value changes (volume nudges, format tweaks) are deliberately ignored: they fire
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/// constantly and never change the device <em>set</em>, so reacting to them would defeat the
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/// whole point of going event-driven.
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/// </summary>
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internal sealed class AudioDeviceChangeNotifier : IMMNotificationClient, IDisposable
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{
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private readonly MMDeviceEnumerator enumerator = new();
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private readonly Action onChange;
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private bool registered;
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public AudioDeviceChangeNotifier(Action onChange)
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{
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this.onChange = onChange;
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enumerator.RegisterEndpointNotificationCallback(this);
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registered = true;
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}
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public void OnDeviceStateChanged(string deviceId, DeviceState newState) => onChange();
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public void OnDeviceAdded(string pwstrDeviceId) => onChange();
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public void OnDeviceRemoved(string deviceId) => onChange();
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public void OnDefaultDeviceChanged(DataFlow flow, Role role, string defaultDeviceId) => onChange();
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public void OnPropertyValueChanged(string pwstrDeviceId, PropertyKey key) { /* ignore — too chatty, no set change */ }
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public void Dispose()
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{
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try { if (registered) enumerator.UnregisterEndpointNotificationCallback(this); }
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catch { /* COM teardown race on shutdown — harmless */ }
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registered = false;
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try { enumerator.Dispose(); } catch { /* ignore */ }
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}
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}
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