108 lines
2.6 KiB
C#
108 lines
2.6 KiB
C#
/*
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* Copyright (c) 2023 ETH Zürich, Educational Development and Technology (LET)
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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using System;
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using System.Collections.Concurrent;
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using System.Timers;
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using SafeExamBrowser.Logging.Contracts;
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using SafeExamBrowser.SystemComponents.Contracts.Registry;
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using SafeExamBrowser.SystemComponents.Contracts.Registry.Events;
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namespace SafeExamBrowser.SystemComponents.Registry
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{
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public class Registry : IRegistry
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{
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private readonly ILogger logger;
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private readonly ConcurrentBag<(string key, string name, object value)> values;
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private Timer timer;
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public event RegistryValueChangedEventHandler ValueChanged;
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public Registry(ILogger logger)
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{
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this.logger = logger;
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this.values = new ConcurrentBag<(string key, string name, object value)>();
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}
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public void StartMonitoring(string key, string name)
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{
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const int ONE_SECOND = 1000;
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if (timer?.Enabled != true)
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{
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timer = new Timer(ONE_SECOND);
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timer.AutoReset = true;
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timer.Elapsed += Timer_Elapsed;
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timer.Start();
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}
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if (TryRead(key, name, out var value))
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{
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values.Add((key, name, value));
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logger.Debug($"Started monitoring value '{name}' from registry key '{key}'. Initial value: '{value}'.");
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}
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else
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{
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logger.Error($"Failed to start monitoring value '{name}' from registry key '{key}'!");
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}
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}
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public void StopMonitoring()
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{
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while (!values.IsEmpty)
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{
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values.TryTake(out _);
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}
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if (timer != null)
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{
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timer.Stop();
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logger.Debug("Stopped monitoring the registry.");
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}
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}
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public bool TryRead(string key, string name, out object value)
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{
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var success = true;
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value = default;
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try
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{
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value = Microsoft.Win32.Registry.GetValue(key, name, default);
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}
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catch (Exception e)
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{
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success = false;
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logger.Error($"Failed to read value '{name}' from registry key '{key}'!", e);
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}
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return success;
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}
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private void Timer_Elapsed(object sender, ElapsedEventArgs e)
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{
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foreach (var item in values)
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{
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if (TryRead(item.key, item.name, out var value))
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{
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if (item.value != value)
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{
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logger.Debug($"Value '{item.name}' from registry key '{item.key}' has changed from '{item.value}' to '{value}'!");
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ValueChanged?.Invoke(item.value, value);
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}
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}
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else
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{
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logger.Error($"Failed to monitor value '{item.name}' from registry key '{item.key}'!");
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}
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}
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}
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}
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}
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