refactor content API to fix load errors with decentralised cache (#524)

1 files changed, 0 insertions, 653 deletions

diff --git a/src/SMAPI/Framework/SContentManager.cs b/src/SMAPI/Framework/SContentManager.cs
deleted file mode 100644
index e97e655d..00000000
--- a/src/SMAPI/Framework/SContentManager.cs
+++ /dev/null
@@ -1,653 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Diagnostics.CodeAnalysis;
-using System.Diagnostics.Contracts;
-using System.Globalization;
-using System.IO;
-using System.Linq;
-using Microsoft.Xna.Framework;
-using Microsoft.Xna.Framework.Content;
-using Microsoft.Xna.Framework.Graphics;
-using StardewModdingAPI.Framework.Content;
-using StardewModdingAPI.Framework.Exceptions;
-using StardewModdingAPI.Framework.Reflection;
-using StardewModdingAPI.Framework.Utilities;
-using StardewValley;
-
-namespace StardewModdingAPI.Framework
-{
-    /// <summary>A minimal content manager which defers to SMAPI's core content logic.</summary>
-    internal class SContentManager : LocalizedContentManager
-    {
-        /*********
-        ** Properties
-        *********/
-        /// <summary>The central coordinator which manages content managers.</summary>
-        private readonly ContentCoordinator Coordinator;
-
-        /// <summary>The underlying asset cache.</summary>
-        private readonly ContentCache Cache;
-
-        /// <summary>Encapsulates monitoring and logging.</summary>
-        private readonly IMonitor Monitor;
-
-        /// <summary>A lookup which indicates whether the asset is localisable (i.e. the filename contains the locale), if previously loaded.</summary>
-        private readonly IDictionary<string, bool> IsLocalisableLookup;
-
-        /// <summary>The language enum values indexed by locale code.</summary>
-        private readonly IDictionary<string, LocalizedContentManager.LanguageCode> LanguageCodes;
-
-        /// <summary>The assets currently being intercepted by <see cref="IAssetLoader"/> instances. This is used to prevent infinite loops when a loader loads a new asset.</summary>
-        private readonly ContextHash<string> AssetsBeingLoaded = new ContextHash<string>();
-
-        /// <summary>The path prefix for assets in mod folders.</summary>
-        private readonly string ModContentPrefix;
-
-        /// <summary>A callback to invoke when the content manager is being disposed.</summary>
-        private readonly Action<SContentManager> OnDisposing;
-
-        /// <summary>Interceptors which provide the initial versions of matching assets.</summary>
-        private IDictionary<IModMetadata, IList<IAssetLoader>> Loaders => this.Coordinator.Loaders;
-
-        /// <summary>Interceptors which edit matching assets after they're loaded.</summary>
-        private IDictionary<IModMetadata, IList<IAssetEditor>> Editors => this.Coordinator.Editors;
-
-        /// <summary>Whether the content coordinator has been disposed.</summary>
-        private bool IsDisposed;
-
-
-        /*********
-        ** Accessors
-        *********/
-        /// <summary>A name for the mod manager. Not guaranteed to be unique.</summary>
-        public string Name { get; }
-
-        /// <summary>Whether this content manager is wrapped around a mod folder.</summary>
-        public bool IsModFolder { get; }
-
-        /// <summary>The current language as a constant.</summary>
-        public LocalizedContentManager.LanguageCode Language => this.GetCurrentLanguage();
-
-        /// <summary>The absolute path to the <see cref="ContentManager.RootDirectory"/>.</summary>
-        public string FullRootDirectory => Path.Combine(Constants.ExecutionPath, this.RootDirectory);
-
-
-        /*********
-        ** Public methods
-        *********/
-        /// <summary>Construct an instance.</summary>
-        /// <param name="name">A name for the mod manager. Not guaranteed to be unique.</param>
-        /// <param name="serviceProvider">The service provider to use to locate services.</param>
-        /// <param name="rootDirectory">The root directory to search for content.</param>
-        /// <param name="currentCulture">The current culture for which to localise content.</param>
-        /// <param name="coordinator">The central coordinator which manages content managers.</param>
-        /// <param name="monitor">Encapsulates monitoring and logging.</param>
-        /// <param name="reflection">Simplifies access to private code.</param>
-        /// <param name="isModFolder">Whether this content manager is wrapped around a mod folder.</param>
-        /// <param name="onDisposing">A callback to invoke when the content manager is being disposed.</param>
-        public SContentManager(string name, IServiceProvider serviceProvider, string rootDirectory, CultureInfo currentCulture, ContentCoordinator coordinator, IMonitor monitor, Reflector reflection, Action<SContentManager> onDisposing, bool isModFolder)
-                : base(serviceProvider, rootDirectory, currentCulture)
-        {
-            // init
-            this.Name = name;
-            this.IsModFolder = isModFolder;
-            this.Coordinator = coordinator ?? throw new ArgumentNullException(nameof(coordinator));
-            this.Cache = new ContentCache(this, reflection);
-            this.Monitor = monitor ?? throw new ArgumentNullException(nameof(monitor));
-            this.ModContentPrefix = this.GetAssetNameFromFilePath(Constants.ModPath, ContentSource.GameContent);
-            this.OnDisposing = onDisposing;
-
-            // get asset data
-            this.LanguageCodes = this.GetKeyLocales().ToDictionary(p => p.Value, p => p.Key, StringComparer.InvariantCultureIgnoreCase);
-            this.IsLocalisableLookup = reflection.GetField<IDictionary<string, bool>>(this, "_localizedAsset").GetValue();
-
-        }
-
-        /// <summary>Load an asset that has been processed by the content pipeline.</summary>
-        /// <typeparam name="T">The type of asset to load.</typeparam>
-        /// <param name="assetName">The asset path relative to the loader root directory, not including the <c>.xnb</c> extension.</param>
-        public override T Load<T>(string assetName)
-        {
-            return this.Load<T>(assetName, LocalizedContentManager.CurrentLanguageCode);
-        }
-
-        /// <summary>Load an asset that has been processed by the content pipeline.</summary>
-        /// <typeparam name="T">The type of asset to load.</typeparam>
-        /// <param name="assetName">The asset path relative to the loader root directory, not including the <c>.xnb</c> extension.</param>
-        /// <param name="language">The language code for which to load content.</param>
-        public override T Load<T>(string assetName, LanguageCode language)
-        {
-            // normalise asset key
-            this.AssertValidAssetKeyFormat(assetName);
-            assetName = this.NormaliseAssetName(assetName);
-
-            // load game content
-            if (!this.IsModFolder && !assetName.StartsWith(this.ModContentPrefix))
-                return this.LoadImpl<T>(assetName, language);
-
-            // load mod content
-            SContentLoadException GetContentError(string reasonPhrase) => new SContentLoadException($"Failed loading content asset '{assetName}': {reasonPhrase}");
-            try
-            {
-                // try cache
-                if (this.IsLoaded(assetName))
-                    return this.LoadImpl<T>(assetName, language);
-
-                // get file
-                FileInfo file = this.GetModFile(assetName);
-                if (!file.Exists)
-                    throw GetContentError("the specified path doesn't exist.");
-
-                // load content
-                switch (file.Extension.ToLower())
-                {
-                    // XNB file
-                    case ".xnb":
-                        return this.LoadImpl<T>(assetName, language);
-
-                    // unpacked map
-                    case ".tbin":
-                        throw GetContentError($"can't read unpacked map file '{assetName}' directly from the underlying content manager. It must be loaded through the mod's {typeof(IModHelper)}.{nameof(IModHelper.Content)} helper.");
-
-                    // unpacked image
-                    case ".png":
-                        // validate
-                        if (typeof(T) != typeof(Texture2D))
-                            throw GetContentError($"can't read file with extension '{file.Extension}' as type '{typeof(T)}'; must be type '{typeof(Texture2D)}'.");
-
-                        // fetch & cache
-                        using (FileStream stream = File.OpenRead(file.FullName))
-                        {
-                            Texture2D texture = Texture2D.FromStream(Game1.graphics.GraphicsDevice, stream);
-                            texture = this.PremultiplyTransparency(texture);
-                            this.Inject(assetName, texture);
-                            return (T)(object)texture;
-                        }
-
-                    default:
-                        throw GetContentError($"unknown file extension '{file.Extension}'; must be one of '.png', '.tbin', or '.xnb'.");
-                }
-            }
-            catch (Exception ex) when (!(ex is SContentLoadException))
-            {
-                if (ex.GetInnermostException() is DllNotFoundException dllEx && dllEx.Message == "libgdiplus.dylib")
-                    throw GetContentError("couldn't find libgdiplus, which is needed to load mod images. Make sure Mono is installed and you're running the game through the normal launcher.");
-                throw new SContentLoadException($"The content manager failed loading content asset '{assetName}'.", ex);
-            }
-        }
-
-        /// <summary>Load the base asset without localisation.</summary>
-        /// <typeparam name="T">The type of asset to load.</typeparam>
-        /// <param name="assetName">The asset path relative to the loader root directory, not including the <c>.xnb</c> extension.</param>
-        public override T LoadBase<T>(string assetName)
-        {
-            return this.Load<T>(assetName, LanguageCode.en);
-        }
-
-        /// <summary>Inject an asset into the cache.</summary>
-        /// <typeparam name="T">The type of asset to inject.</typeparam>
-        /// <param name="assetName">The asset path relative to the loader root directory, not including the <c>.xnb</c> extension.</param>
-        /// <param name="value">The asset value.</param>
-        public void Inject<T>(string assetName, T value)
-        {
-            assetName = this.NormaliseAssetName(assetName);
-            this.Cache[assetName] = value;
-        }
-
-        /// <summary>Create a new content manager for temporary use.</summary>
-        public override LocalizedContentManager CreateTemporary()
-        {
-            return this.Coordinator.CreateContentManager("(temporary)", isModFolder: false);
-        }
-
-        /// <summary>Normalise path separators in a file path. For asset keys, see <see cref="NormaliseAssetName"/> instead.</summary>
-        /// <param name="path">The file path to normalise.</param>
-        [Pure]
-        public string NormalisePathSeparators(string path)
-        {
-            return this.Cache.NormalisePathSeparators(path);
-        }
-
-        /// <summary>Normalise an asset name so it's consistent with the underlying cache.</summary>
-        /// <param name="assetName">The asset key.</param>
-        [Pure]
-        public string NormaliseAssetName(string assetName)
-        {
-            return this.Cache.NormaliseKey(assetName);
-        }
-
-        /// <summary>Assert that the given key has a valid format.</summary>
-        /// <param name="key">The asset key to check.</param>
-        /// <exception cref="SContentLoadException">The asset key is empty or contains invalid characters.</exception>
-        [SuppressMessage("ReSharper", "ParameterOnlyUsedForPreconditionCheck.Local", Justification = "Parameter is only used for assertion checks by design.")]
-        public void AssertValidAssetKeyFormat(string key)
-        {
-            // NOTE: the game checks for ContentLoadException to handle invalid keys, so avoid
-            // throwing other types like ArgumentException here.
-            if (string.IsNullOrWhiteSpace(key))
-                throw new SContentLoadException("The asset key or local path is empty.");
-            if (key.Intersect(Path.GetInvalidPathChars()).Any())
-                throw new SContentLoadException("The asset key or local path contains invalid characters.");
-        }
-
-        /// <summary>Convert an absolute file path into an appropriate asset name.</summary>
-        /// <param name="absolutePath">The absolute path to the file.</param>
-        /// <param name="relativeTo">The folder to which to get a relative path.</param>
-        public string GetAssetNameFromFilePath(string absolutePath, ContentSource relativeTo)
-        {
-#if SMAPI_FOR_WINDOWS
-            // XNA doesn't allow absolute asset paths, so get a path relative to the source folder
-            string sourcePath = relativeTo == ContentSource.GameContent ? this.Coordinator.FullRootDirectory : this.FullRootDirectory;
-            return this.GetRelativePath(sourcePath, absolutePath);
-#else
-            // MonoGame is weird about relative paths on Mac, but allows absolute paths
-            return absolutePath;
-#endif
-        }
-
-        /****
-        ** Content loading
-        ****/
-        /// <summary>Get the current content locale.</summary>
-        public string GetLocale()
-        {
-            return this.GetLocale(this.GetCurrentLanguage());
-        }
-
-        /// <summary>The locale for a language.</summary>
-        /// <param name="language">The language.</param>
-        public string GetLocale(LocalizedContentManager.LanguageCode language)
-        {
-            return this.LanguageCodeString(language);
-        }
-
-        /// <summary>Get whether the content manager has already loaded and cached the given asset.</summary>
-        /// <param name="assetName">The asset path relative to the loader root directory, not including the <c>.xnb</c> extension.</param>
-        public bool IsLoaded(string assetName)
-        {
-            assetName = this.Cache.NormaliseKey(assetName);
-            return this.IsNormalisedKeyLoaded(assetName);
-        }
-
-        /// <summary>Get the cached asset keys.</summary>
-        public IEnumerable<string> GetAssetKeys()
-        {
-            return this.Cache.Keys
-                .Select(this.GetAssetName)
-                .Distinct();
-        }
-
-        /****
-        ** Cache invalidation
-        ****/
-        /// <summary>Purge matched assets from the cache.</summary>
-        /// <param name="predicate">Matches the asset keys to invalidate.</param>
-        /// <param name="dispose">Whether to dispose invalidated assets. This should only be <c>true</c> when they're being invalidated as part of a dispose, to avoid crashing the game.</param>
-        /// <returns>Returns the number of invalidated assets.</returns>
-        public IEnumerable<string> InvalidateCache(Func<string, Type, bool> predicate, bool dispose = false)
-        {
-            HashSet<string> removeAssetNames = new HashSet<string>(StringComparer.InvariantCultureIgnoreCase);
-            this.Cache.Remove((key, type) =>
-            {
-                this.ParseCacheKey(key, out string assetName, out _);
-                if (removeAssetNames.Contains(assetName) || predicate(assetName, type))
-                {
-                    removeAssetNames.Add(assetName);
-                    return true;
-                }
-                return false;
-            });
-
-            return removeAssetNames;
-        }
-
-        /// <summary>Dispose held resources.</summary>
-        /// <param name="isDisposing">Whether the content manager is being disposed (rather than finalized).</param>
-        protected override void Dispose(bool isDisposing)
-        {
-            if (this.IsDisposed)
-                return;
-            this.IsDisposed = true;
-
-            this.OnDisposing(this);
-            base.Dispose(isDisposing);
-        }
-
-        /// <inheritdoc />
-        public override void Unload()
-        {
-            if (this.IsDisposed)
-                return; // base logic doesn't allow unloading twice, which happens due to SMAPI and the game both unloading
-
-            base.Unload();
-        }
-
-
-        /*********
-        ** Private methods
-        *********/
-        /****
-        ** Asset name/key handling
-        ****/
-        /// <summary>Get a directory or file path relative to the content root.</summary>
-        /// <param name="sourcePath">The source file path.</param>
-        /// <param name="targetPath">The target file path.</param>
-        private string GetRelativePath(string sourcePath, string targetPath)
-        {
-            return PathUtilities.GetRelativePath(sourcePath, targetPath);
-        }
-
-        /// <summary>Get the locale codes (like <c>ja-JP</c>) used in asset keys.</summary>
-        private IDictionary<LocalizedContentManager.LanguageCode, string> GetKeyLocales()
-        {
-            // create locale => code map
-            IDictionary<LocalizedContentManager.LanguageCode, string> map = new Dictionary<LocalizedContentManager.LanguageCode, string>();
-            foreach (LocalizedContentManager.LanguageCode code in Enum.GetValues(typeof(LocalizedContentManager.LanguageCode)))
-                map[code] = this.GetLocale(code);
-
-            return map;
-        }
-
-        /// <summary>Get the asset name from a cache key.</summary>
-        /// <param name="cacheKey">The input cache key.</param>
-        private string GetAssetName(string cacheKey)
-        {
-            this.ParseCacheKey(cacheKey, out string assetName, out string _);
-            return assetName;
-        }
-
-        /// <summary>Parse a cache key into its component parts.</summary>
-        /// <param name="cacheKey">The input cache key.</param>
-        /// <param name="assetName">The original asset name.</param>
-        /// <param name="localeCode">The asset locale code (or <c>null</c> if not localised).</param>
-        private void ParseCacheKey(string cacheKey, out string assetName, out string localeCode)
-        {
-            // handle localised key
-            if (!string.IsNullOrWhiteSpace(cacheKey))
-            {
-                int lastSepIndex = cacheKey.LastIndexOf(".", StringComparison.InvariantCulture);
-                if (lastSepIndex >= 0)
-                {
-                    string suffix = cacheKey.Substring(lastSepIndex + 1, cacheKey.Length - lastSepIndex - 1);
-                    if (this.LanguageCodes.ContainsKey(suffix))
-                    {
-                        assetName = cacheKey.Substring(0, lastSepIndex);
-                        localeCode = cacheKey.Substring(lastSepIndex + 1, cacheKey.Length - lastSepIndex - 1);
-                        return;
-                    }
-                }
-            }
-
-            // handle simple key
-            assetName = cacheKey;
-            localeCode = null;
-        }
-
-        /****
-        ** Cache handling
-        ****/
-        /// <summary>Get whether an asset has already been loaded.</summary>
-        /// <param name="normalisedAssetName">The normalised asset name.</param>
-        private bool IsNormalisedKeyLoaded(string normalisedAssetName)
-        {
-            // default English
-            if (this.Language == LocalizedContentManager.LanguageCode.en)
-                return this.Cache.ContainsKey(normalisedAssetName);
-
-            // translated
-            string localeKey = $"{normalisedAssetName}.{this.GetLocale(this.GetCurrentLanguage())}";
-            if (this.IsLocalisableLookup.TryGetValue(localeKey, out bool localisable))
-            {
-                return localisable
-                    ? this.Cache.ContainsKey(localeKey)
-                    : this.Cache.ContainsKey(normalisedAssetName);
-            }
-
-            // not loaded yet
-            return false;
-        }
-
-        /****
-        ** Content loading
-        ****/
-        /// <summary>Load an asset name without heuristics to support mod content.</summary>
-        /// <typeparam name="T">The type of asset to load.</typeparam>
-        /// <param name="assetName">The asset path relative to the loader root directory, not including the <c>.xnb</c> extension.</param>
-        /// <param name="language">The language code for which to load content.</param>
-        private T LoadImpl<T>(string assetName, LocalizedContentManager.LanguageCode language)
-        {
-            // skip if already loaded
-            if (this.IsNormalisedKeyLoaded(assetName))
-                return base.Load<T>(assetName, language);
-
-            // load asset
-            T data;
-            if (this.AssetsBeingLoaded.Contains(assetName))
-            {
-                this.Monitor.Log($"Broke loop while loading asset '{assetName}'.", LogLevel.Warn);
-                this.Monitor.Log($"Bypassing mod loaders for this asset. Stack trace:\n{Environment.StackTrace}", LogLevel.Trace);
-                data = base.Load<T>(assetName, language);
-            }
-            else
-            {
-                data = this.AssetsBeingLoaded.Track(assetName, () =>
-                {
-                    string locale = this.GetLocale(language);
-                    IAssetInfo info = new AssetInfo(locale, assetName, typeof(T), this.NormaliseAssetName);
-                    IAssetData asset =
-                        this.ApplyLoader<T>(info)
-                        ?? new AssetDataForObject(info, base.Load<T>(assetName, language), this.NormaliseAssetName);
-                    asset = this.ApplyEditors<T>(info, asset);
-                    return (T)asset.Data;
-                });
-            }
-
-            // update cache & return data
-            this.Inject(assetName, data);
-            return data;
-        }
-
-        /// <summary>Get a file from the mod folder.</summary>
-        /// <param name="path">The asset path relative to the content folder.</param>
-        private FileInfo GetModFile(string path)
-        {
-            // try exact match
-            FileInfo file = new FileInfo(Path.Combine(this.FullRootDirectory, path));
-
-            // try with default extension
-            if (!file.Exists && file.Extension.ToLower() != ".xnb")
-            {
-                FileInfo result = new FileInfo(file.FullName + ".xnb");
-                if (result.Exists)
-                    file = result;
-            }
-
-            return file;
-        }
-
-        /// <summary>Load the initial asset from the registered <see cref="Loaders"/>.</summary>
-        /// <param name="info">The basic asset metadata.</param>
-        /// <returns>Returns the loaded asset metadata, or <c>null</c> if no loader matched.</returns>
-        private IAssetData ApplyLoader<T>(IAssetInfo info)
-        {
-            // find matching loaders
-            var loaders = this.GetInterceptors(this.Loaders)
-                .Where(entry =>
-                {
-                    try
-                    {
-                        return entry.Value.CanLoad<T>(info);
-                    }
-                    catch (Exception ex)
-                    {
-                        entry.Key.LogAsMod($"Mod failed when checking whether it could load asset '{info.AssetName}', and will be ignored. Error details:\n{ex.GetLogSummary()}", LogLevel.Error);
-                        return false;
-                    }
-                })
-                .ToArray();
-
-            // validate loaders
-            if (!loaders.Any())
-                return null;
-            if (loaders.Length > 1)
-            {
-                string[] loaderNames = loaders.Select(p => p.Key.DisplayName).ToArray();
-                this.Monitor.Log($"Multiple mods want to provide the '{info.AssetName}' asset ({string.Join(", ", loaderNames)}), but an asset can't be loaded multiple times. SMAPI will use the default asset instead; uninstall one of the mods to fix this. (Message for modders: you should usually use {typeof(IAssetEditor)} instead to avoid conflicts.)", LogLevel.Warn);
-                return null;
-            }
-
-            // fetch asset from loader
-            IModMetadata mod = loaders[0].Key;
-            IAssetLoader loader = loaders[0].Value;
-            T data;
-            try
-            {
-                data = loader.Load<T>(info);
-                this.Monitor.Log($"{mod.DisplayName} loaded asset '{info.AssetName}'.", LogLevel.Trace);
-            }
-            catch (Exception ex)
-            {
-                mod.LogAsMod($"Mod crashed when loading asset '{info.AssetName}'. SMAPI will use the default asset instead. Error details:\n{ex.GetLogSummary()}", LogLevel.Error);
-                return null;
-            }
-
-            // validate asset
-            if (data == null)
-            {
-                mod.LogAsMod($"Mod incorrectly set asset '{info.AssetName}' to a null value; ignoring override.", LogLevel.Error);
-                return null;
-            }
-
-            // return matched asset
-            return new AssetDataForObject(info, data, this.NormaliseAssetName);
-        }
-
-        /// <summary>Apply any <see cref="Editors"/> to a loaded asset.</summary>
-        /// <typeparam name="T">The asset type.</typeparam>
-        /// <param name="info">The basic asset metadata.</param>
-        /// <param name="asset">The loaded asset.</param>
-        private IAssetData ApplyEditors<T>(IAssetInfo info, IAssetData asset)
-        {
-            IAssetData GetNewData(object data) => new AssetDataForObject(info, data, this.NormaliseAssetName);
-
-            // edit asset
-            foreach (var entry in this.GetInterceptors(this.Editors))
-            {
-                // check for match
-                IModMetadata mod = entry.Key;
-                IAssetEditor editor = entry.Value;
-                try
-                {
-                    if (!editor.CanEdit<T>(info))
-                        continue;
-                }
-                catch (Exception ex)
-                {
-                    mod.LogAsMod($"Mod crashed when checking whether it could edit asset '{info.AssetName}', and will be ignored. Error details:\n{ex.GetLogSummary()}", LogLevel.Error);
-                    continue;
-                }
-
-                // try edit
-                object prevAsset = asset.Data;
-                try
-                {
-                    editor.Edit<T>(asset);
-                    this.Monitor.Log($"{mod.DisplayName} intercepted {info.AssetName}.", LogLevel.Trace);
-                }
-                catch (Exception ex)
-                {
-                    mod.LogAsMod($"Mod crashed when editing asset '{info.AssetName}', which may cause errors in-game. Error details:\n{ex.GetLogSummary()}", LogLevel.Error);
-                }
-
-                // validate edit
-                if (asset.Data == null)
-                {
-                    mod.LogAsMod($"Mod incorrectly set asset '{info.AssetName}' to a null value; ignoring override.", LogLevel.Warn);
-                    asset = GetNewData(prevAsset);
-                }
-                else if (!(asset.Data is T))
-                {
-                    mod.LogAsMod($"Mod incorrectly set asset '{asset.AssetName}' to incompatible type '{asset.Data.GetType()}', expected '{typeof(T)}'; ignoring override.", LogLevel.Warn);
-                    asset = GetNewData(prevAsset);
-                }
-            }
-
-            // return result
-            return asset;
-        }
-
-        /// <summary>Get all registered interceptors from a list.</summary>
-        private IEnumerable<KeyValuePair<IModMetadata, T>> GetInterceptors<T>(IDictionary<IModMetadata, IList<T>> entries)
-        {
-            foreach (var entry in entries)
-            {
-                IModMetadata mod = entry.Key;
-                IList<T> interceptors = entry.Value;
-
-                // registered editors
-                foreach (T interceptor in interceptors)
-                    yield return new KeyValuePair<IModMetadata, T>(mod, interceptor);
-            }
-        }
-
-        /// <summary>Premultiply a texture's alpha values to avoid transparency issues in the game. This is only possible if the game isn't currently drawing.</summary>
-        /// <param name="texture">The texture to premultiply.</param>
-        /// <returns>Returns a premultiplied texture.</returns>
-        /// <remarks>Based on <a href="https://gist.github.com/Layoric/6255384">code by Layoric</a>.</remarks>
-        private Texture2D PremultiplyTransparency(Texture2D texture)
-        {
-            // validate
-            if (Context.IsInDrawLoop)
-                throw new NotSupportedException("Can't load a PNG file while the game is drawing to the screen. Make sure you load content outside the draw loop.");
-
-            // process texture
-            SpriteBatch spriteBatch = Game1.spriteBatch;
-            GraphicsDevice gpu = Game1.graphics.GraphicsDevice;
-            using (RenderTarget2D renderTarget = new RenderTarget2D(Game1.graphics.GraphicsDevice, texture.Width, texture.Height))
-            {
-                // create blank render target to premultiply
-                gpu.SetRenderTarget(renderTarget);
-                gpu.Clear(Color.Black);
-
-                // multiply each color by the source alpha, and write just the color values into the final texture
-                spriteBatch.Begin(SpriteSortMode.Immediate, new BlendState
-                {
-                    ColorDestinationBlend = Blend.Zero,
-                    ColorWriteChannels = ColorWriteChannels.Red | ColorWriteChannels.Green | ColorWriteChannels.Blue,
-                    AlphaDestinationBlend = Blend.Zero,
-                    AlphaSourceBlend = Blend.SourceAlpha,
-                    ColorSourceBlend = Blend.SourceAlpha
-                });
-                spriteBatch.Draw(texture, texture.Bounds, Color.White);
-                spriteBatch.End();
-
-                // copy the alpha values from the source texture into the final one without multiplying them
-                spriteBatch.Begin(SpriteSortMode.Immediate, new BlendState
-                {
-                    ColorWriteChannels = ColorWriteChannels.Alpha,
-                    AlphaDestinationBlend = Blend.Zero,
-                    ColorDestinationBlend = Blend.Zero,
-                    AlphaSourceBlend = Blend.One,
-                    ColorSourceBlend = Blend.One
-                });
-                spriteBatch.Draw(texture, texture.Bounds, Color.White);
-                spriteBatch.End();
-
-                // release GPU
-                gpu.SetRenderTarget(null);
-
-                // extract premultiplied data
-                Color[] data = new Color[texture.Width * texture.Height];
-                renderTarget.GetData(data);
-
-                // unset texture from GPU to regain control
-                gpu.Textures[0] = null;
-
-                // update texture with premultiplied data
-                texture.SetData(data);
-            }
-
-            return texture;
-        }
-    }
-}