private static void AssertSeparatorChoice(string path, char?separator)
{
if (separator == null)
{
return;
}
var root = GetPathRoot(path);
if (root == null)
{
return;
}
ControlFlow.Assert(!IsWinRoot(root) || separator == WinSeparator, $"For Windows-rooted paths the separator must be '{WinSeparator}'.");
ControlFlow.Assert(!IsUncRoot(root) || separator == UncSeparator, $"For UNC-rooted paths the separator must be '{UncSeparator}'.");
ControlFlow.Assert(!IsUnixRoot(root) || separator == UnixSeparator, $"For Unix-rooted paths the separator must be '{UnixSeparator}'.");
}
// TODO: check usages
public static string GetRelativePath(string basePath, string destinationPath, bool normalize = true)
{
basePath = NormalizePath(basePath);
destinationPath = NormalizePath(destinationPath);
var separator = GetSeparator(basePath);
ControlFlow.Assert(separator == GetSeparator(destinationPath), "Separators do not match.");
ControlFlow.Assert(!IsWinRoot(basePath) || Path.GetPathRoot(basePath) == Path.GetPathRoot(destinationPath), "Root must be same.");
var baseParts = basePath.Split(new[] { separator }, StringSplitOptions.RemoveEmptyEntries);
var destinationParts = destinationPath.Split(new[] { separator }, StringSplitOptions.RemoveEmptyEntries);
var sameParts = baseParts.Zip(destinationParts, (a, b) => new { Base = a, Destination = b })
.Count(x => x.Base.Equals(x.Destination, StringComparison.OrdinalIgnoreCase));
return(Enumerable.Repeat("..", baseParts.Length - sameParts).ToList()
.Concat(destinationParts.Skip(sameParts).ToList()).Join(separator));
}
// ReSharper disable once CyclomaticComplexity
public static string NormalizePath(string path, char?separator = null)
{
AssertSeparatorChoice(path, separator);
path = path ?? string.Empty;
separator = separator ?? GetSeparator(path);
var root = GetPathRoot(path);
var tail = root == null ? path : path.Substring(root.Length);
var tailParts = tail.Split(s_allSeparators, StringSplitOptions.RemoveEmptyEntries).ToList();
for (var i = 0; i < tailParts.Count;)
{
var part = tailParts[i];
if (IsUpwardsDirectory(part))
{
if (tailParts.Take(i).All(IsUpwardsDirectory))
{
ControlFlow.Assert(i > 0 || root == null, $"Cannot normalize '{path}' beyond path root.");
i++;
continue;
}
tailParts.RemoveAt(i);
tailParts.RemoveAt(i - 1);
i--;
continue;
}
if (IsSameDirectory(part))
{
tailParts.RemoveAt(i);
continue;
}
i++;
}
return(Combine(root, tailParts.Join(separator.ToString()), separator));
}