Merge pull request #542 from NotCoffee418/GetLastInputInfo

Add User32.GetLastInputInfo

Author: AArnott

src/User32/PublicAPI.Unshipped.txt

@@ -44,4 +44,12 @@ static extern PInvoke.User32.EnumDisplaySettings(char* lpszDeviceName, uint iMod
 static extern PInvoke.User32.EnumDisplaySettingsEx(char* lpszDeviceName, uint iModeNum, PInvoke.DEVMODE* lpDevMode, PInvoke.User32.EnumDisplaySettingsExFlags dwFlags) -> bool
 static extern PInvoke.User32.LoadString(System.IntPtr hInstance, uint uID, char* lpBuffer, int cchBufferMax) -> int
 static extern PInvoke.User32.UnregisterClass(string lpClassName, System.IntPtr hInstance) -> bool
-static readonly PInvoke.User32.DPI_AWARENESS_CONTEXT_UNAWARE_GDISCALED -> System.IntPtr
+static readonly PInvoke.User32.DPI_AWARENESS_CONTEXT_UNAWARE_GDISCALED -> System.IntPtr
+static PInvoke.User32.GetLastInputInfo(System.IntPtr plii) -> bool
+static PInvoke.User32.GetLastInputInfo(out PInvoke.User32.LASTINPUTINFO plii) -> bool
+static extern PInvoke.User32.GetLastInputInfo(PInvoke.User32.LASTINPUTINFO* plii) -> bool
+PInvoke.User32.LASTINPUTINFO
+PInvoke.User32.LASTINPUTINFO.LASTINPUTINFO() -> void
+PInvoke.User32.LASTINPUTINFO.cbSize -> int
+PInvoke.User32.LASTINPUTINFO.dwTime -> uint
+static PInvoke.User32.LASTINPUTINFO.Create() -> PInvoke.User32.LASTINPUTINFO

src/User32/User32+LASTINPUTINFO.cs

@@ -0,0 +1,36 @@
+// Copyright © .NET Foundation and Contributors. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+namespace PInvoke
+{
+    using System;
+    using System.Runtime.InteropServices;
+
+    /// <content>
+    /// Contains the <see cref="LASTINPUTINFO"/> nested type.
+    /// </content>
+    public partial class User32
+    {
+        /// <summary>
+        /// Contains the time of the last input. It is used with the <see cref="GetLastInputInfo(LASTINPUTINFO*)"/> function.
+        /// </summary>
+        public struct LASTINPUTINFO
+        {
+            /// <summary>
+            /// The size of the structure, in bytes. This member must be set to <c>sizeof(LASTINPUTINFO)</c>.
+            /// </summary>
+            public int cbSize;
+
+            /// <summary>
+            /// The tick count when the last input event was received.
+            /// </summary>
+            public uint dwTime;
+
+            /// <summary>
+            /// Initializes a new instance of the <see cref="LASTINPUTINFO"/> struct.
+            /// </summary>
+            /// <returns>An initialized instance of the struct.</returns>
+            public static unsafe LASTINPUTINFO Create() => new LASTINPUTINFO { cbSize = sizeof(LASTINPUTINFO) };
+        }
+    }
+}

src/User32/User32.cs

@@ -3944,6 +3944,27 @@ public static unsafe extern uint MsgWaitForMultipleObjectsEx(
             WakeMask dwWakeMask,
             MsgWaitForMultipleObjectsExFlags dwFlags);
 
+        /// <summary>
+        /// Retrieves the time of the last input event.
+        /// </summary>
+        /// <param name="plii">A pointer to a <see cref="LASTINPUTINFO"/> structure that receives the time of the last input event.</param>
+        /// <returns>
+        /// If the function succeeds, the return value is nonzero.
+        /// If the function fails, the return value is zero.
+        /// </returns>
+        /// <remarks>
+        /// This function is useful for input idle detection. However, GetLastInputInfo does not provide system-wide
+        /// user input information across all running sessions. Rather, GetLastInputInfo provides session-specific user input
+        /// information for only the session that invoked the function.
+        /// The tick count when the last input event was received (see <see cref="LASTINPUTINFO"/>) is not guaranteed to be incremental.
+        /// In some cases, the value might be less than the tick count of a prior event. For example, this can be caused by
+        /// a timing gap between the raw input thread and the desktop thread or an event raised by SendInput, which supplies its own tick count.
+        /// </remarks>
+        [DllImport(nameof(User32))]
+        [return: MarshalAs(UnmanagedType.Bool)]
+        public static extern unsafe bool GetLastInputInfo(
+            [Friendly(FriendlyFlags.Out)] LASTINPUTINFO* plii);
+
         /// <summary>
         /// The BeginPaint function prepares the specified window for painting and fills a <see cref="PAINTSTRUCT"/> structure with information about the painting.
         /// </summary>