internal static string GetRelativePath()

in src/Sarif.Viewer.VisualStudio.Core/SdkUiUtilities.cs [433:491]
49 lines of code
8 McCabe index (conditional complexity)

        internal static string GetRelativePath(string fromDirectory, string toPath)
        {
            // Both paths need to be rooted to calculate a relative path
            if (!Path.IsPathRooted(fromDirectory) ||
                !Path.IsPathRooted(toPath))
            {
                return toPath;
            }

            // If toPath is on a different drive then there is no relative path
            if (!string.Equals(Path.GetPathRoot(fromDirectory),
                                    Path.GetPathRoot(toPath),
                                    StringComparison.OrdinalIgnoreCase))
            {
                return toPath;
            }

            // Get the canonical path. This resolves directory names like "\.\" and "\..\".
            fromDirectory = Path.GetFullPath(fromDirectory);
            toPath = Path.GetFullPath(toPath);

            string[] fromDirectories = fromDirectory.Split(s_directorySeparatorArray, StringSplitOptions.RemoveEmptyEntries);
            string[] toDirectories = toPath.Split(s_directorySeparatorArray, StringSplitOptions.RemoveEmptyEntries);

            int length = Math.Min(fromDirectories.Length, toDirectories.Length);

            // We know at least the drive letter matches so start at index 1
            int firstDifference = 1;

            // Find the common root
            for (; firstDifference < length; firstDifference++)
            {
                if (!string.Equals(fromDirectories[firstDifference],
                                        toDirectories[firstDifference],
                                        StringComparison.OrdinalIgnoreCase))
                {
                    break;
                }
            }

            var relativePath = new StringCollection();

            // Add relative paths to get from fromDirectory to the common root
            for (int i = firstDifference; i < fromDirectories.Length; i++)
            {
                relativePath.Add("..");
            }

            // Add the relative paths from toPath
            for (int i = firstDifference; i < toDirectories.Length; i++)
            {
                relativePath.Add(toDirectories[i]);
            }

            // Create the relative path
            string[] relativeParts = new string[relativePath.Count];
            relativePath.CopyTo(relativeParts, 0);
            return string.Join(Path.DirectorySeparatorChar.ToString(), relativeParts);
        }