TweetDuck/Migration/MigrationUtils.cs

using System;
using System.Diagnostics;
using System.Linq;
using Microsoft.Win32;

namespace TweetDck.Migration{
    static class MigrationUtils{
        public static bool RunUninstaller(string guid, int timeout){
            try{
                Process uninstaller = Process.Start(new ProcessStartInfo{
                    FileName = "msiexec.exe",
                    Arguments = "/x "+guid+" /quiet /qn",
                    Verb = "runas"
                });

                if (uninstaller != null){
                    if (timeout > 0){
                        uninstaller.WaitForExit(timeout); // it appears that the process is restarted or something that triggers this, but it shouldn't be a problem
                    }

                    uninstaller.Close();
                }

                return true;
            }catch(Exception){
                return false;
            }
        }

        public static string FindProgramGuidByDisplayName(string displayName){
            Predicate<RegistryKey> predicate = key => displayName.Equals(key.GetValue("DisplayName") as string, StringComparison.OrdinalIgnoreCase);
            string guid;

            return FindMatchingSubKey(Registry.LocalMachine, @"SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall", predicate, out guid) ||
                   FindMatchingSubKey(Registry.LocalMachine, @"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall", predicate, out guid) ||
                   FindMatchingSubKey(Registry.CurrentUser, @"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall", predicate, out guid)
                   ? guid : null;
        }

        private static bool FindMatchingSubKey(RegistryKey keyHandle, string path, Predicate<RegistryKey> predicate, out string guid){
            string outputId = null;

            try{
                RegistryKey parentKey = keyHandle.OpenSubKey(path, false);
                if (parentKey == null)throw new InvalidOperationException();

                foreach(RegistryKey subKey in parentKey.GetSubKeyNames().Select(subName => parentKey.OpenSubKey(subName, false)).Where(subKey => subKey != null)){
                    if (predicate(subKey)){
                        outputId = subKey.Name.Substring(subKey.Name.LastIndexOf('\\')+1);
                        subKey.Close();
                        break;
                    }

                    subKey.Close();
                }

                parentKey.Close();
            }catch(Exception){
                guid = null;
                return false;
            }

            return (guid = outputId) != null;
        }
    }
}