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* Looks like we have a working POC that can clear the memory now
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+252
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5 files changed

+252
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‎MemPlus/App.xaml.cs

-2
Original file line numberDiff line numberDiff line change
@@ -1,8 +1,6 @@
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using System;
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using System.Collections.Generic;
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using System.Configuration;
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using System.Data;
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using System.Linq;
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using System.Threading.Tasks;
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using System.Windows;
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‎MemPlus/Classes/MemPlus.cs

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@@ -0,0 +1,221 @@
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using System;
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using System.Collections.Generic;
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using System.ComponentModel;
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using System.Diagnostics;
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using System.Runtime.InteropServices;
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using System.Security.Principal;
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namespace MemPlus.Classes
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{
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/// <summary>
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/// System Cache Information structure for x86 working set
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/// </summary>
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[StructLayout(LayoutKind.Sequential, Pack = 1)]
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internal struct SystemCacheInformation
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{
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internal uint CurrentSize;
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internal uint PeakSize;
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internal uint PageFaultCount;
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internal uint MinimumWorkingSet;
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internal uint MaximumWorkingSet;
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}
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/// <summary>
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/// System Cache Information structure for x64 working set
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/// </summary>
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[StructLayout(LayoutKind.Sequential, Pack = 1)]
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internal struct SystemCacheInformation64Bit
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{
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internal long CurrentSize;
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internal long PeakSize;
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internal long PageFaultCount;
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internal long MinimumWorkingSet;
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internal long MaximumWorkingSet;
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}
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/// <summary>
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/// Token Privileges structure, used for adjusting token privileges
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/// </summary>
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[StructLayout(LayoutKind.Sequential, Pack = 1)]
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internal struct TokenPrivileges
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{
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internal int Count;
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internal long Luid;
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internal int Attr;
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}
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/// <summary>
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/// Enum containing System Information class values
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/// </summary>
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internal enum SystemInformationClass
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{
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SystemFileCacheInformation = 0x0015,
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SystemMemoryListInformation = 0x0050
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}
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/// <summary>
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/// Class containing methods to 'optimize' or clear memory usage in Windows
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/// </summary>
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internal class MemPlus
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{
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/// <summary>
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/// Constant int used for TokenPrivileges Atrr variable
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/// </summary>
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private const int SePrivilegeEnabled = 2;
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/// <summary>
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/// Adjust memory quotas for a process
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/// </summary>
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private const string SeIncreaseQuotaName = "SeIncreaseQuotaPrivilege";
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/// <summary>
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/// Profile single process
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/// </summary>
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private const string SeProfileSingleProcessName = "SeProfileSingleProcessPrivilege";
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private const int MemoryPurgeStandbyList = 4;
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[DllImport("advapi32.dll", SetLastError = true)]
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private static extern bool LookupPrivilegeValue(string host, string name, ref long pluid);
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[DllImport("advapi32.dll", SetLastError = true)]
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private static extern bool AdjustTokenPrivileges(IntPtr htok, bool disall, ref TokenPrivileges newst, int len, IntPtr prev, IntPtr relen);
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[DllImport("ntdll.dll")]
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private static extern uint NtSetSystemInformation(int infoClass, IntPtr info, int length);
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[DllImport("psapi.dll")]
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private static extern int EmptyWorkingSet(IntPtr hwProc);
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/// <summary>
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/// Clear the working sets of all processes that are available to the application
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/// </summary>
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internal static void EmptyWorkingSetFunction()
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{
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List<string> successes = new List<string>();
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List<string> failures = new List<string>();
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foreach (Process process in Process.GetProcesses())
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{
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try
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{
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// Empty the working set of the process
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EmptyWorkingSet(process.Handle);
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// Add it to the list of successfully cleared processes
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successes.Add(process.ProcessName);
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}
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catch (Exception ex)
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{
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failures.Add(process.ProcessName + ": " + ex.Message);
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}
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}
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//Print the lists with successful and failed processes
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Console.WriteLine("Success (count): " + successes.Count);
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Console.WriteLine("---");
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foreach (string success in successes)
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{
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Console.WriteLine(success);
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}
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Console.WriteLine("Failed (count) " + failures.Count);
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Console.WriteLine("---");
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foreach (string error in failures)
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{
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Console.WriteLine(error);
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}
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}
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/// <summary>
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/// Check whether the system is running a x86 or x64 working set
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/// </summary>
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/// <returns>A boolean to indicate whether or not the system is 64 bit</returns>
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private static bool Is64BitMode()
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{
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return Marshal.SizeOf(typeof(IntPtr)) == 8;
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}
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/// <summary>
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/// Clear the FileSystem cache
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/// </summary>
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/// <param name="clearStandbyCache">Set whether or not to clear cache that is in standby</param>
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internal static void ClearFileSystemCache(bool clearStandbyCache)
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{
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try
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{
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//Check if privilege can be increased
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if (SetIncreasePrivilege(SeIncreaseQuotaName))
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{
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uint ntSetSystemInformationRet;
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int systemInfoLength;
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GCHandle gcHandle;
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//Depending on the working set, call the right external function using the right parameters
150+
if (!Is64BitMode())
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{
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SystemCacheInformation cacheInformation =
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new SystemCacheInformation
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{
155+
MinimumWorkingSet = uint.MaxValue,
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MaximumWorkingSet = uint.MaxValue
157+
};
158+
systemInfoLength = Marshal.SizeOf(cacheInformation);
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gcHandle = GCHandle.Alloc(cacheInformation, GCHandleType.Pinned);
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ntSetSystemInformationRet = NtSetSystemInformation((int)SystemInformationClass.SystemFileCacheInformation, gcHandle.AddrOfPinnedObject(), systemInfoLength);
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gcHandle.Free();
162+
}
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else
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{
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SystemCacheInformation64Bit information64Bit =
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new SystemCacheInformation64Bit
167+
{
168+
MinimumWorkingSet = -1L,
169+
MaximumWorkingSet = -1L
170+
};
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systemInfoLength = Marshal.SizeOf(information64Bit);
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gcHandle = GCHandle.Alloc(information64Bit, GCHandleType.Pinned);
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ntSetSystemInformationRet = NtSetSystemInformation((int)SystemInformationClass.SystemFileCacheInformation, gcHandle.AddrOfPinnedObject(), systemInfoLength);
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gcHandle.Free();
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}
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// If value is not equal to zero, things didn't go right :(
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if (ntSetSystemInformationRet != 0) throw new Exception("NtSetSystemInformation: ", new Win32Exception(Marshal.GetLastWin32Error()));
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}
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// If we don't have to clear the standby cache or cannot increase privileges, don't hesitate to clear the standby cache, otherwise we can clear the standby cache
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if (!clearStandbyCache || !SetIncreasePrivilege(SeProfileSingleProcessName)) return;
182+
{
183+
int systemInfoLength = Marshal.SizeOf(MemoryPurgeStandbyList);
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GCHandle gcHandle = GCHandle.Alloc(MemoryPurgeStandbyList, GCHandleType.Pinned);
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uint ntSetSystemInformationRet = NtSetSystemInformation((int)SystemInformationClass.SystemMemoryListInformation, gcHandle.AddrOfPinnedObject(), systemInfoLength);
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gcHandle.Free();
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if (ntSetSystemInformationRet != 0) throw new Exception("NtSetSystemInformation: ", new Win32Exception(Marshal.GetLastWin32Error()));
188+
}
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}
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catch (Exception ex)
191+
{
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Console.Write(ex.ToString());
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}
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}
195+
196+
/// <summary>
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/// Increase the Privilege
198+
/// </summary>
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/// <param name="privilegeName">The name of the privilege that needs to be increased</param>
200+
/// <returns>A boolean value indicating whether or not the operation was successfull</returns>
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private static bool SetIncreasePrivilege(string privilegeName)
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{
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using (WindowsIdentity current = WindowsIdentity.GetCurrent(TokenAccessLevels.Query | TokenAccessLevels.AdjustPrivileges))
204+
{
205+
TokenPrivileges newst;
206+
newst.Count = 1;
207+
newst.Luid = 0L;
208+
newst.Attr = SePrivilegeEnabled;
209+
210+
// If we can't look up the privilege value, we can't function properly
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if (!LookupPrivilegeValue(null, privilegeName, ref newst.Luid)) throw new Exception("LookupPrivilegeValue: ", new Win32Exception(Marshal.GetLastWin32Error()));
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//Enables or disables privileges in a specified access token
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int adjustTokenPrivilegesRet = AdjustTokenPrivileges(current.Token, false, ref newst, 0, IntPtr.Zero, IntPtr.Zero) ? 1 : 0;
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// Return value of zero indicates an error
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if (adjustTokenPrivilegesRet == 0) throw new Exception("AdjustTokenPrivileges: ", new Win32Exception(Marshal.GetLastWin32Error()));
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return adjustTokenPrivilegesRet != 0;
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}
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}
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}
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}

‎MemPlus/MemPlus.csproj

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@@ -38,13 +38,7 @@
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</PropertyGroup>
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<ItemGroup>
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<Reference Include="System" />
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<Reference Include="System.Data" />
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<Reference Include="System.Xml" />
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<Reference Include="Microsoft.CSharp" />
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<Reference Include="System.Core" />
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<Reference Include="System.Xml.Linq" />
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<Reference Include="System.Data.DataSetExtensions" />
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<Reference Include="System.Net.Http" />
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<Reference Include="System.Xaml">
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<RequiredTargetFramework>4.0</RequiredTargetFramework>
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</Reference>
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<DependentUpon>App.xaml</DependentUpon>
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<SubType>Code</SubType>
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</Compile>
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<Compile Include="Classes\MemPlus.cs" />
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<Compile Include="Windows\MainWindow.xaml.cs">
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<DependentUpon>MainWindow.xaml</DependentUpon>
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<SubType>Code</SubType>
@@ -96,8 +91,6 @@
9691
<ItemGroup>
9792
<None Include="App.config" />
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</ItemGroup>
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<ItemGroup>
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<Folder Include="Classes\" />
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</ItemGroup>
94+
<ItemGroup />
10295
<Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
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</Project>

‎MemPlus/Windows/MainWindow.xaml

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xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
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xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
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xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
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xmlns:local="clr-namespace:MemPlus.Windows"
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mc:Ignorable="d"
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Title="MemPlus" Height="350" Width="525" WindowStartupLocation="CenterScreen">
9-
<Grid>
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Title="MemPlus" Height="150" Width="300" WindowStartupLocation="CenterScreen">
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<Grid HorizontalAlignment="Center" VerticalAlignment="Center">
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<Grid.RowDefinitions>
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<RowDefinition Height="Auto"></RowDefinition>
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</Grid.RowDefinitions>
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<Button Content="Clear memory" Click="BtnClearMemory_OnClick" Padding="5">
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</Button>
1115
</Grid>
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</Window>

‎MemPlus/Windows/MainWindow.xaml.cs

+21-2
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@@ -1,15 +1,34 @@
1-
using System.Windows;
1+
using System;
2+
using System.Windows;
23

34
namespace MemPlus.Windows
45
{
6+
/// <inheritdoc cref="Window" />
57
/// <summary>
68
/// Interaction logic for MainWindow.xaml
79
/// </summary>
8-
public partial class MainWindow : Window
10+
public partial class MainWindow
911
{
1012
public MainWindow()
1113
{
1214
InitializeComponent();
1315
}
16+
17+
private void BtnClearMemory_OnClick(object sender, RoutedEventArgs e)
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{
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try
20+
{
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//Clear working set of all processes that the user has access to
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Classes.MemPlus.EmptyWorkingSetFunction();
23+
//Clear file system cache
24+
Classes.MemPlus.ClearFileSystemCache(true);
25+
26+
MessageBox.Show("Your memory is has now been cleared of any non-essential data.", "MemPlus",MessageBoxButton.OK, MessageBoxImage.Information);
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}
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catch (Exception ex)
29+
{
30+
MessageBox.Show(ex.Message, "MemPlus", MessageBoxButton.OK, MessageBoxImage.Error);
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}
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}
1433
}
1534
}

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