Add live debugger frontend and mutex stall recovery (#383)

src/SharpEmu.Debugger/Protocol/DebugRequest.cs

@@ -0,0 +1,152 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using System.Globalization;
+using System.Text.Json;
+
+namespace SharpEmu.Debugger.Protocol;
+
+/// <summary>
+/// A parsed client request: a <see cref="Command"/> verb plus a bag of named
+/// arguments backed by the original JSON. Numeric arguments accept either JSON
+/// numbers or <c>"0x"</c>-prefixed hex strings so addresses read naturally on
+/// the wire.
+/// </summary>
+public sealed class DebugRequest
+{
+    private readonly JsonElement _root;
+
+    private DebugRequest(string command, JsonElement root)
+    {
+        Command = command;
+        _root = root;
+    }
+
+    /// <summary>The lower-cased command verb.</summary>
+    public string Command { get; }
+
+    /// <summary>
+    /// Parses a single JSON object into a request. Returns false when the text is
+    /// not a JSON object or is missing a string <c>command</c> field.
+    /// </summary>
+    public static bool TryParse(string json, out DebugRequest request, out string error)
+    {
+        request = null!;
+        error = string.Empty;
+        try
+        {
+            using var document = JsonDocument.Parse(json);
+            var root = document.RootElement.Clone();
+            if (root.ValueKind != JsonValueKind.Object)
+            {
+                error = "Request must be a JSON object.";
+                return false;
+            }
+
+            if (!root.TryGetProperty("command", out var commandElement) ||
+                commandElement.ValueKind != JsonValueKind.String)
+            {
+                error = "Request is missing a string 'command'.";
+                return false;
+            }
+
+            var command = commandElement.GetString() ?? string.Empty;
+            request = new DebugRequest(command.Trim().ToLowerInvariant(), root);
+            return true;
+        }
+        catch (JsonException ex)
+        {
+            error = $"Malformed JSON: {ex.Message}";
+            return false;
+        }
+    }
+
+    public bool TryGetString(string name, out string value)
+    {
+        if (_root.TryGetProperty(name, out var element) && element.ValueKind == JsonValueKind.String)
+        {
+            value = element.GetString() ?? string.Empty;
+            return true;
+        }
+
+        value = string.Empty;
+        return false;
+    }
+
+    public bool TryGetUInt64(string name, out ulong value)
+    {
+        value = 0;
+        if (!_root.TryGetProperty(name, out var element))
+        {
+            return false;
+        }
+
+        switch (element.ValueKind)
+        {
+            case JsonValueKind.Number:
+                return element.TryGetUInt64(out value);
+            case JsonValueKind.String:
+                return TryParseNumber(element.GetString(), out value);
+            default:
+                return false;
+        }
+    }
+
+    public bool TryGetInt32(string name, out int value)
+    {
+        value = 0;
+        if (!_root.TryGetProperty(name, out var element))
+        {
+            return false;
+        }
+
+        switch (element.ValueKind)
+        {
+            case JsonValueKind.Number:
+                return element.TryGetInt32(out value);
+            case JsonValueKind.String when TryParseNumber(element.GetString(), out var parsed) && parsed <= int.MaxValue:
+                value = (int)parsed;
+                return true;
+            default:
+                return false;
+        }
+    }
+
+    public bool TryGetBool(string name, out bool value)
+    {
+        value = false;
+        if (!_root.TryGetProperty(name, out var element))
+        {
+            return false;
+        }
+
+        switch (element.ValueKind)
+        {
+            case JsonValueKind.True:
+                value = true;
+                return true;
+            case JsonValueKind.False:
+                value = false;
+                return true;
+            default:
+                return false;
+        }
+    }
+
+    private static bool TryParseNumber(string? text, out ulong value)
+    {
+        value = 0;
+        if (string.IsNullOrWhiteSpace(text))
+        {
+            return false;
+        }
+
+        text = text.Trim();
+        if (text.StartsWith("0x", StringComparison.OrdinalIgnoreCase))
+        {
+            return ulong.TryParse(text.AsSpan(2), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out value);
+        }
+
+        return ulong.TryParse(text, NumberStyles.Integer, CultureInfo.InvariantCulture, out value);
+    }
+}