using System; using System.Collections.Generic; using System.IO; namespace StardewModdingAPI.Toolkit.Utilities.PathLookups { /// <summary>An API for case-insensitive file lookups within a root directory.</summary> internal class CaseInsensitiveFileLookup : IFileLookup { /********* ** Fields *********/ /// <summary>The root directory path for relative paths.</summary> private readonly string RootPath; /// <summary>A case-insensitive lookup of file paths within the <see cref="RootPath"/>. Each path is listed in both file path and asset name format, so it's usable in both contexts without needing to re-parse paths.</summary> private readonly Lazy<Dictionary<string, string>> RelativePathCache; /// <summary>The case-insensitive file lookups by root path.</summary> private static readonly Dictionary<string, CaseInsensitiveFileLookup> CachedRoots = new(StringComparer.OrdinalIgnoreCase); /********* ** Public methods *********/ /// <summary>Construct an instance.</summary> /// <param name="rootPath">The root directory path for relative paths.</param> /// <param name="searchOption">Which directories to scan from the root.</param> public CaseInsensitiveFileLookup(string rootPath, SearchOption searchOption = SearchOption.AllDirectories) { this.RootPath = PathUtilities.NormalizePath(rootPath); this.RelativePathCache = new(() => this.GetRelativePathCache(searchOption)); } /// <inheritdoc /> public FileInfo GetFile(string relativePath) { // invalid path if (string.IsNullOrWhiteSpace(relativePath)) throw new InvalidOperationException("Can't get a file from an empty relative path."); // already cached if (this.RelativePathCache.Value.TryGetValue(relativePath, out string? resolved)) return new(Path.Combine(this.RootPath, resolved)); // keep capitalization as-is FileInfo file = new(Path.Combine(this.RootPath, relativePath)); if (file.Exists) this.RelativePathCache.Value[relativePath] = relativePath; return file; } /// <inheritdoc /> public void Add(string relativePath) { // skip if cache isn't created yet (no need to add files manually in that case) if (!this.RelativePathCache.IsValueCreated) return; // skip if already cached if (this.RelativePathCache.Value.ContainsKey(relativePath)) return; // make sure path exists relativePath = PathUtilities.NormalizePath(relativePath); if (!File.Exists(Path.Combine(this.RootPath, relativePath))) throw new InvalidOperationException($"Can't add relative path '{relativePath}' to the case-insensitive cache for '{this.RootPath}' because that file doesn't exist."); // cache path this.RelativePathCache.Value[relativePath] = relativePath; } /// <summary>Get a cached dictionary of relative paths within a root path, for case-insensitive file lookups.</summary> /// <param name="rootPath">The root path to scan.</param> public static CaseInsensitiveFileLookup GetCachedFor(string rootPath) { rootPath = PathUtilities.NormalizePath(rootPath); if (!CaseInsensitiveFileLookup.CachedRoots.TryGetValue(rootPath, out CaseInsensitiveFileLookup? cache)) CaseInsensitiveFileLookup.CachedRoots[rootPath] = cache = new CaseInsensitiveFileLookup(rootPath); return cache; } /********* ** Private methods *********/ /// <summary>Get a case-insensitive lookup of file paths (see <see cref="RelativePathCache"/>).</summary> /// <param name="searchOption">Which directories to scan from the root.</param> private Dictionary<string, string> GetRelativePathCache(SearchOption searchOption) { Dictionary<string, string> cache = new(StringComparer.OrdinalIgnoreCase); foreach (string path in Directory.EnumerateFiles(this.RootPath, "*", searchOption)) { string relativePath = path.Substring(this.RootPath.Length + 1); cache[relativePath] = relativePath; } return cache; } } }