1 files changed, 252 insertions, 0 deletions
diff --git a/src/SMAPI/Framework/ContentManagers/GameContentManager.cs b/src/SMAPI/Framework/ContentManagers/GameContentManager.cs
new file mode 100644
index 00000000..cfedb5af
--- /dev/null
+++ b/src/SMAPI/Framework/ContentManagers/GameContentManager.cs
@@ -0,0 +1,252 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using StardewModdingAPI.Framework.Content;
+using StardewModdingAPI.Framework.Reflection;
+using StardewModdingAPI.Framework.Utilities;
+using StardewValley;
+
+namespace StardewModdingAPI.Framework.ContentManagers
+{
+    /// <summary>A content manager which handles reading files from the game content folder with support for interception.</summary>
+    internal class GameContentManager : BaseContentManager
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <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>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>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;
+
+
+        /*********
+        ** 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="onDisposing">A callback to invoke when the content manager is being disposed.</param>
+        public GameContentManager(string name, IServiceProvider serviceProvider, string rootDirectory, CultureInfo currentCulture, ContentCoordinator coordinator, IMonitor monitor, Reflector reflection, Action<BaseContentManager> onDisposing)
+            : base(name, serviceProvider, rootDirectory, currentCulture, coordinator, monitor, reflection, onDisposing, isModFolder: false)
+        {
+            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>
+        /// <param name="language">The language code for which to load content.</param>
+        public override T Load<T>(string assetName, LanguageCode language)
+        {
+            assetName = this.AssertAndNormaliseAssetName(assetName);
+
+            // get from cache
+            if (this.IsLoaded(assetName))
+                return base.Load<T>(assetName, language);
+
+            // get managed asset
+            if (this.Coordinator.TryParseManagedAssetKey(assetName, out string contentManagerID, out string relativePath))
+            {
+                T managedAsset = this.Coordinator.LoadAndCloneManagedAsset<T>(assetName, contentManagerID, relativePath, language);
+                this.Inject(assetName, managedAsset);
+                return managedAsset;
+            }
+
+            // 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.AssertAndNormaliseAssetName);
+                    IAssetData asset =
+                        this.ApplyLoader<T>(info)
+                        ?? new AssetDataForObject(info, base.Load<T>(assetName, language), this.AssertAndNormaliseAssetName);
+                    asset = this.ApplyEditors<T>(info, asset);
+                    return (T)asset.Data;
+                });
+            }
+
+            // update cache & return data
+            this.Inject(assetName, data);
+            return data;
+        }
+
+        /// <summary>Create a new content manager for temporary use.</summary>
+        public override LocalizedContentManager CreateTemporary()
+        {
+            return this.Coordinator.CreateGameContentManager("(temporary)");
+        }
+
+
+        /*********
+        ** Private methods
+        *********/
+        /// <summary>Get whether an asset has already been loaded.</summary>
+        /// <param name="normalisedAssetName">The normalised asset name.</param>
+        protected override bool IsNormalisedKeyLoaded(string normalisedAssetName)
+        {
+            // default English
+            if (this.Language == LocalizedContentManager.LanguageCode.en || this.Coordinator.IsManagedAssetKey(normalisedAssetName))
+                return this.Cache.ContainsKey(normalisedAssetName);
+
+            // translated
+            string localeKey = $"{normalisedAssetName}.{this.GetLocale(this.GetCurrentLanguage())}";
+            if (this.IsLocalisableLookup.TryGetValue(localeKey, out bool localisable))
+            {
+                return localisable
+                    ? this.Cache.ContainsKey(localeKey)
+                    : this.Cache.ContainsKey(normalisedAssetName);
+            }
+
+            // not loaded yet
+            return false;
+        }
+
+        /// <summary>Load the initial asset from the registered <see cref="Loaders"/>.</summary>
+        /// <param name="info">The basic asset metadata.</param>
+        /// <returns>Returns the loaded asset metadata, or <c>null</c> if no loader matched.</returns>
+        private IAssetData ApplyLoader<T>(IAssetInfo info)
+        {
+            // find matching loaders
+            var loaders = this.GetInterceptors(this.Loaders)
+                .Where(entry =>
+                {
+                    try
+                    {
+                        return entry.Value.CanLoad<T>(info);
+                    }
+                    catch (Exception ex)
+                    {
+                        entry.Key.LogAsMod($"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.AssertAndNormaliseAssetName);
+        }
+
+        /// <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.AssertAndNormaliseAssetName);
+
+            // 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);
+            }
+        }
+    }
+}