138 lines
3.3 KiB
C#
138 lines
3.3 KiB
C#
using System;
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using System.IO;
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using System.Threading;
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namespace Server;
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/// <summary>
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/// Owns a console input stream. Each line read is atomically either delivered to a
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/// waiting <see cref="ReadLine"/> caller (a prompt) or dispatched as a command via the
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/// supplied lookup. EOF ends the loop instead of spinning. Correct-by-construction:
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/// the prompt-vs-command decision is made under a single lock at the moment a line is read.
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/// </summary>
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internal sealed class ConsoleInputPump
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{
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private readonly TextReader _input;
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private readonly Func<string, Action<string>> _lookup;
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private readonly object _gate = new();
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private readonly AutoResetEvent _promptDelivered = new(false);
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private bool _promptPending;
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private string _promptResult;
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private volatile bool _running = true;
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public ConsoleInputPump(TextReader input, Func<string, Action<string>> lookup)
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{
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_input = input ?? throw new ArgumentNullException(nameof(input));
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_lookup = lookup ?? throw new ArgumentNullException(nameof(lookup));
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}
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public bool Running => _running;
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public void Stop()
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{
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_running = false;
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ReleasePendingPrompt(null);
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}
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public void Run()
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{
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while (_running && !Core.Closing)
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{
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string line;
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try
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{
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line = _input.ReadLine();
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}
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catch
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{
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break;
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}
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if (line == null)
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{
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break; // EOF — never spin
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}
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bool isCommand;
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lock (_gate)
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{
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if (_promptPending)
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{
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_promptResult = line;
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_promptPending = false;
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_promptDelivered.Set();
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isCommand = false;
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}
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else
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{
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isCommand = true;
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}
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}
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if (!isCommand)
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{
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continue;
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}
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var trimmed = line.Trim();
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if (trimmed.Length == 0)
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{
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continue;
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}
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var split = trimmed.Split(' ', 2);
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var action = _lookup(split[0].ToLower());
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if (action == null)
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{
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continue;
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}
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try
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{
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action(split.Length > 1 ? split[1] : string.Empty);
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}
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catch
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{
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// Command handlers log their own failures; never let one kill the loop.
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}
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}
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_running = false;
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ReleasePendingPrompt(null);
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}
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public string ReadLine()
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{
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lock (_gate)
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{
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if (!_running)
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{
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return null;
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}
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_promptResult = null;
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_promptPending = true;
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}
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_promptDelivered.WaitOne();
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lock (_gate)
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{
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return _promptResult;
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}
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}
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private void ReleasePendingPrompt(string result)
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{
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lock (_gate)
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{
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if (_promptPending)
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{
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_promptResult = result;
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_promptPending = false;
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_promptDelivered.Set();
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}
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}
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}
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}
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