using System; using System.Collections.Generic; using System.Diagnostics.Contracts; using System.IO; using System.Linq; using System.Text.RegularExpressions; namespace StardewModdingAPI.Toolkit.Utilities { /// <summary>Provides utilities for normalizing file paths.</summary> public static class PathUtilities { /********* ** Fields *********/ /// <summary>The root prefix for a Windows UNC path.</summary> private const string WindowsUncRoot = @"\\"; /********* ** Accessors *********/ /// <summary>The possible directory separator characters in a file path.</summary> public static readonly char[] PossiblePathSeparators = new[] { '/', '\\', Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar }.Distinct().ToArray(); /// <summary>The preferred directory separator character in an asset key.</summary> public static readonly char PreferredPathSeparator = Path.DirectorySeparatorChar; /********* ** Public methods *********/ /// <summary>Get the segments from a path (e.g. <c>/usr/bin/example</c> => <c>usr</c>, <c>bin</c>, and <c>example</c>).</summary> /// <param name="path">The path to split.</param> /// <param name="limit">The number of segments to match. Any additional segments will be merged into the last returned part.</param> [Pure] public static string[] GetSegments(string path, int? limit = null) { return limit.HasValue ? path.Split(PathUtilities.PossiblePathSeparators, limit.Value, StringSplitOptions.RemoveEmptyEntries) : path.Split(PathUtilities.PossiblePathSeparators, StringSplitOptions.RemoveEmptyEntries); } /// <summary>Normalize separators in a file path.</summary> /// <param name="path">The file path to normalize.</param> [Pure] public static string NormalizePath(string path) { path = path?.Trim(); if (string.IsNullOrEmpty(path)) return path; // get basic path format (e.g. /some/asset\\path/ => some\asset\path) string[] segments = PathUtilities.GetSegments(path); string newPath = string.Join(PathUtilities.PreferredPathSeparator.ToString(), segments); // keep root prefix bool hasRoot = false; if (path.StartsWith(PathUtilities.WindowsUncRoot)) { newPath = PathUtilities.WindowsUncRoot + newPath; hasRoot = true; } else if (PathUtilities.PossiblePathSeparators.Contains(path[0])) { newPath = PathUtilities.PreferredPathSeparator + newPath; hasRoot = true; } // keep trailing separator if ((!hasRoot || segments.Any()) && PathUtilities.PossiblePathSeparators.Contains(path[path.Length - 1])) newPath += PathUtilities.PreferredPathSeparator; return newPath; } /// <summary>Get a directory or file path relative to a given source path. If no relative path is possible (e.g. the paths are on different drives), an absolute path is returned.</summary> /// <param name="sourceDir">The source folder path.</param> /// <param name="targetPath">The target folder or file path.</param> /// <remarks> /// /// NOTE: this is a heuristic implementation that works in the cases SMAPI needs it for, but it doesn't handle all edge cases (e.g. case-sensitivity on Linux, or traversing between UNC paths on Windows). This should be replaced with the more comprehensive <c>Path.GetRelativePath</c> if the game ever migrates to .NET Core. /// /// </remarks> [Pure] public static string GetRelativePath(string sourceDir, string targetPath) { // convert to URIs Uri from = new Uri(sourceDir.TrimEnd(PathUtilities.PossiblePathSeparators) + "/"); Uri to = new Uri(targetPath.TrimEnd(PathUtilities.PossiblePathSeparators) + "/"); if (from.Scheme != to.Scheme) throw new InvalidOperationException($"Can't get path for '{targetPath}' relative to '{sourceDir}'."); // get relative path string rawUrl = Uri.UnescapeDataString(from.MakeRelativeUri(to).ToString()); if (rawUrl.StartsWith("file://")) rawUrl = PathUtilities.WindowsUncRoot + rawUrl.Substring("file://".Length); string relative = PathUtilities.NormalizePath(rawUrl); // normalize if (relative == "") relative = "."; else { // trim trailing slash from URL if (relative.EndsWith(PathUtilities.PreferredPathSeparator.ToString())) relative = relative.Substring(0, relative.Length - 1); // fix root if (relative.StartsWith("file:") && !targetPath.Contains("file:")) relative = relative.Substring("file:".Length); } return relative; } /// <summary>Get whether a path is relative and doesn't try to climb out of its containing folder (e.g. doesn't contain <c>../</c>).</summary> /// <param name="path">The path to check.</param> [Pure] public static bool IsSafeRelativePath(string path) { if (string.IsNullOrWhiteSpace(path)) return true; return !Path.IsPathRooted(path) && PathUtilities.GetSegments(path).All(segment => segment.Trim() != ".."); } /// <summary>Get whether a string is a valid 'slug', containing only basic characters that are safe in all contexts (e.g. filenames, URLs, etc).</summary> /// <param name="str">The string to check.</param> [Pure] public static bool IsSlug(string str) { return !Regex.IsMatch(str, "[^a-z0-9_.-]", RegexOptions.IgnoreCase); } /// <summary>Get the paths which exceed the OS length limit.</summary> /// <param name="rootPath">The root path to search.</param> internal static IEnumerable<string> GetTooLongPaths(string rootPath) { if (!Directory.Exists(rootPath)) return new string[0]; return Directory .EnumerateFileSystemEntries(rootPath, "*.*", SearchOption.AllDirectories) .Where(PathUtilities.IsPathTooLong); } /// <summary>Get whether a file or directory path exceeds the OS path length limit.</summary> /// <param name="path">The path to test.</param> internal static bool IsPathTooLong(string path) { try { _ = Path.GetFullPath(path); return false; } catch (PathTooLongException) { return true; } } } }