QuickLook/QuickLook.Plugin/QuickLook.Plugin.TextViewer/Detectors/JSONDetector.cs

// Copyright © 2017-2025 QL-Win Contributors
//
// This file is part of QuickLook program.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

using System.Text.RegularExpressions;

namespace QuickLook.Plugin.TextViewer.Detectors;

public class JSONDetector : IFormatDetector
{
    public string Name => "JSON";

    public string Extension => ".json";

    public bool Detect(string text)
    {
        if (string.IsNullOrWhiteSpace(text)) return false;

        // TODO: Use AsSpan to improve

        var trimmedStart = text.TrimStart();

        if (trimmedStart.StartsWith("{") || trimmedStart.StartsWith("["))
        {
            var trimmedEnd = text.TrimEnd();

            if (trimmedEnd.EndsWith("}") || trimmedEnd.EndsWith("]"))
            {
                // At least one key exists
                if (Regex.IsMatch(text, @"""[^""]+""\s*:"))
                {
                    return true;
                }
            }
        }

        return false;
    }
}