TeamCity.VSTest.TestLogger/TestAttachmentPathResolver.cs

namespace TeamCity.VSTest.TestLogger;

using System;
using System.Text;

internal class TestAttachmentPathResolver : ITestAttachmentPathResolver
{
    // different file systems have varying limitations on the maximum length of directory names
    // normally the limit is around 255 characters
    // in order to successfully create a directory and not catch an exception,
    // we control the length of the directory name with this constant
    private const int DirectoryMaxLength = 200;
    private const char NamespaceDelimiter = '.';
    private const char DirectorySeparator = '/';

    public string Resolve(string testFullyQualifiedName)
    {
        var testName = DenormalizeNamespaceDelimiter(testFullyQualifiedName);
        var result = new StringBuilder();
        var position = 0;
        var offset = 0;

        while (position + offset < testName.Length)
        {
            position = ComputePosition(testName, position, offset);
            offset = ComputeOffset(testName, position);

            result.Append(DirectorySeparator);
            result.Append(testName.Substring(position, offset));
        }

        return result.ToString().Trim(DirectorySeparator);
    }

    private static int ComputePosition(string testName, int currentPosition, int currentOffset)
    {
        var position = currentPosition + currentOffset;
        while (position < testName.Length && testName[position] == NamespaceDelimiter)
        {
            position++;
        }

        return position;
    }

    private static int ComputeOffset(string testName, int currentPosition)
    {
        var maxOffset = Math.Min(testName.Length - currentPosition, DirectoryMaxLength);

        for (var i = 0; i < maxOffset; i++)
        {
            if (testName[currentPosition + i] == NamespaceDelimiter)
            {
                return i;
            }
        }

        return maxOffset;
    }

    private static string DenormalizeNamespaceDelimiter(string testName)
    {
        return testName.Replace($"{(ulong)NamespaceDelimiter:x4}", NamespaceDelimiter.ToString());
    }
}