Platforms: remove unused active process check

The last caller of the IsProcessActive() methods in the
ScalarPlatform classes was removed in commit
cedeeaa in PR microsoft#29.

Therefore we can remove this method as well as the native
Windows system call wrappers and enums which were used only
by the WindowPlatform implementation of this method.

Scalar.Common/NativeMethods.cs

@@ -77,24 +77,6 @@ public enum FileAccess : uint
             GENERIC_READ = 2147483648
         }
 
-        [Flags]
-        public enum ProcessAccessFlags : uint
-        {
-            All = 0x001F0FFF,
-            Terminate = 0x00000001,
-            CreateThread = 0x00000002,
-            VirtualMemoryOperation = 0x00000008,
-            VirtualMemoryRead = 0x00000010,
-            VirtualMemoryWrite = 0x00000020,
-            DuplicateHandle = 0x00000040,
-            CreateProcess = 0x000000080,
-            SetQuota = 0x00000100,
-            SetInformation = 0x00000200,
-            QueryInformation = 0x00000400,
-            QueryLimitedInformation = 0x00001000,
-            Synchronize = 0x00100000
-        }
-
         [Flags]
         public enum MoveFileFlags : uint
         {
@@ -190,16 +172,6 @@ public static void ThrowLastWin32Exception(string message)
             throw new Win32Exception(Marshal.GetLastWin32Error(), message);
         }
 
-        [DllImport("kernel32.dll", SetLastError = true)]
-        public static extern SafeFileHandle OpenProcess(
-            ProcessAccessFlags processAccess,
-            bool bInheritHandle,
-            int processId);
-
-        [DllImport("kernel32.dll", SetLastError = true)]
-        [return: MarshalAs(UnmanagedType.Bool)]
-        public static extern bool GetExitCodeProcess(SafeFileHandle hProcess, out uint lpExitCode);
-
         [DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
         private static extern SafeFileHandle CreateFile(
             [In] string lpFileName,

Scalar.Common/Platforms/POSIX/POSIXPlatform.cs

@@ -45,20 +45,6 @@ public override bool TryVerifyAuthenticodeSignature(string path, out string subj
             throw new NotImplementedException();
         }
 
-        public override bool IsProcessActive(int processId)
-        {
-            try
-            {
-                Process process = Process.GetProcessById(processId);
-            }
-            catch (ArgumentException)
-            {
-                return false;
-            }
-
-            return true;
-        }
-
         public override void IsServiceInstalledAndRunning(string name, out bool installed, out bool running)
         {
             throw new NotImplementedException();

Scalar.Common/Platforms/Windows/WindowsPlatform.cs

@@ -1,5 +1,4 @@
 using Microsoft.Win32;
-using Microsoft.Win32.SafeHandles;
 using Scalar.Common;
 using Scalar.Common.FileSystem;
 using Scalar.Common.Git;
@@ -25,8 +24,6 @@ public class WindowsPlatform : ScalarPlatform
         private const string BuildLabRegistryValue = "BuildLab";
         private const string BuildLabExRegistryValue = "BuildLabEx";
 
-        private const int StillActive = 259; /* from Win32 STILL_ACTIVE */
-
         public WindowsPlatform() : base(underConstruction: new UnderConstructionFlags())
         {
         }
@@ -203,37 +200,6 @@ public override bool IsElevated()
             }
         }
 
-        public override bool IsProcessActive(int processId)
-        {
-            using (SafeFileHandle process = NativeMethods.OpenProcess(NativeMethods.ProcessAccessFlags.QueryLimitedInformation, false, processId))
-            {
-                if (!process.IsInvalid)
-                {
-                    uint exitCode;
-                    if (NativeMethods.GetExitCodeProcess(process, out exitCode) && exitCode == StillActive)
-                    {
-                        return true;
-                    }
-                }
-                else
-                {
-                    // The process.IsInvalid may be true when the process doesn't have access to call
-                    // OpenProcess for the specified processId. Fallback to slow way of finding process.
-                    try
-                    {
-                        Process.GetProcessById(processId);
-                        return true;
-                    }
-                    catch (ArgumentException)
-                    {
-                        return false;
-                    }
-                }
-
-                return false;
-            }
-        }
-
         public override void IsServiceInstalledAndRunning(string name, out bool installed, out bool running)
         {
             ServiceController service = ServiceController.GetServices().FirstOrDefault(s => s.ServiceName.Equals(name, StringComparison.Ordinal));

Scalar.Common/ScalarPlatform.cs

@@ -57,7 +57,6 @@ public static void Register(ScalarPlatform platform)
         /// </exception>
         public abstract void PrepareProcessToRunInBackground();
 
-        public abstract bool IsProcessActive(int processId);
         public abstract void IsServiceInstalledAndRunning(string name, out bool installed, out bool running);
         public abstract string GetScalarServiceNamedPipeName(string serviceName);
         public abstract NamedPipeServerStream CreatePipeByName(string pipeName);

Scalar.UnitTests/Mock/Common/MockPlatform.cs

@@ -30,8 +30,6 @@ public class MockPlatform : ScalarPlatform
 
         public override ScalarPlatformConstants Constants { get; } = new MockPlatformConstants();
 
-        public HashSet<int> ActiveProcesses { get; } = new HashSet<int>();
-
         public override void ConfigureVisualStudio(string gitBinPath, ITracer tracer)
         {
             throw new NotSupportedException();
@@ -110,11 +108,6 @@ public override bool IsElevated()
             throw new NotSupportedException();
         }
 
-        public override bool IsProcessActive(int processId)
-        {
-            return this.ActiveProcesses.Contains(processId);
-        }
-
         public override void IsServiceInstalledAndRunning(string name, out bool installed, out bool running)
         {
             throw new NotSupportedException();