src/modules/powerdisplay/PowerDisplay/Helpers/PowerSettingsNative.cs - main - githubmirror/PowerToys

src/modules/powerdisplay/PowerDisplay/Helpers/PowerSettingsNative.cs
99 строк4 KB
moooyo
[PowerDisplay] Rescan monitors on display wake (#47876)
18 май 2026, 09:26
18 май 2026, 09:2638882fd
// Copyright (c) Microsoft Corporation
// The Microsoft Corporation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System;
using System.Runtime.InteropServices;

namespace PowerDisplay.Helpers;

/// <summary>
/// P/Invoke for the console-display-state power-setting notification used by
/// <see cref="DisplayChangeWatcher"/>.
/// </summary>
internal static partial class PowerSettingsNative
{
    /// <summary>
    /// GUID_CONSOLE_DISPLAY_STATE — Windows fires this whenever the console
    /// display's power state changes. Data byte is 0 (off), 1 (on), 2 (dimmed).
    /// Reliable on both S3 and S0ix, and also fires for idle-blank / lid /
    /// screensaver transitions that never enter system sleep.
    /// </summary>
    internal static readonly Guid GuidConsoleDisplayState =
        new("6fe69556-704a-47a0-8f24-c28d936fda47");

    internal const uint DisplayStateOff = 0;
    internal const uint DisplayStateOn = 1;
    internal const uint DisplayStateDimmed = 2;

    /// <summary>
    /// DEVICE_NOTIFY_CALLBACK — Recipient is a pointer to
    /// DEVICE_NOTIFY_SUBSCRIBE_PARAMETERS containing a callback delegate.
    /// </summary>
    internal const uint DeviceNotifyCallback = 0x00000002;

    /// <summary>
    /// Power-broadcast type value passed as the <c>type</c> parameter of the
    /// callback when a subscribed power setting changes.
    /// </summary>
    internal const uint PowerSettingChangeNotification = 0x8013;

    /// <summary>
    /// Callback signature for power-setting notifications.
    /// Windows invokes this on an internal worker thread — implementations
    /// must marshal to their own thread before touching UI / VM state.
    /// </summary>
    /// <remarks>
    /// <see cref="Marshal.GetFunctionPointerForDelegate"/> does NOT root the
    /// delegate against GC. Callers must keep the managed delegate alive (e.g.
    /// via <c>GCHandle.Alloc</c>) for the entire lifetime of the registration,
    /// or Windows will eventually invoke a collected delegate and produce an
    /// access violation.
    /// </remarks>
    /// <param name="context">Opaque context supplied at registration.</param>
    /// <param name="type">Notification type (e.g. <see cref="PowerSettingChangeNotification"/>).</param>
    /// <param name="setting">Pointer to a POWERBROADCAST_SETTING.</param>
    /// <returns>Reserved — must return 0.</returns>
    [UnmanagedFunctionPointer(CallingConvention.Winapi)]
    internal delegate uint DeviceNotifyCallbackRoutine(IntPtr context, uint type, IntPtr setting);

    [StructLayout(LayoutKind.Sequential)]
    internal struct DeviceNotifySubscribeParameters
    {
        public IntPtr Callback;
        public IntPtr Context;
    }

    /// <summary>
    /// POWERBROADCAST_SETTING — the payload Windows passes to the callback.
    /// PowerSetting (16 bytes) + DataLength (4 bytes) precede a variable-length
    /// Data array whose first byte holds the new display state.
    /// </summary>
    internal const int PowerBroadcastSettingDataOffset = 20;

    /// <summary>
    /// Registers a callback to receive notifications when a specific power
    /// setting changes. Free the registration with
    /// <see cref="PowerSettingUnregisterNotification"/> when no longer needed.
    /// </summary>
    /// <returns>
    /// <c>ERROR_SUCCESS</c> (0) on success; otherwise a Win32 error code
    /// (the function returns the error directly; <c>GetLastError</c> is not used).
    /// </returns>
    [LibraryImport("Powrprof.dll")]
    internal static partial uint PowerSettingRegisterNotification(
        ref Guid settingGuid,
        uint flags,
        ref DeviceNotifySubscribeParameters recipient,
        out IntPtr registrationHandle);

    /// <summary>
    /// Cancels a registration previously returned by
    /// <see cref="PowerSettingRegisterNotification"/>.
    /// </summary>
    /// <returns>
    /// <c>ERROR_SUCCESS</c> (0) on success; otherwise a Win32 error code.
    /// </returns>
    [LibraryImport("Powrprof.dll")]
    internal static partial uint PowerSettingUnregisterNotification(IntPtr registrationHandle);
}