path: root/src/StardewModdingAPI/Framework/SContentManager.cs

using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Reflection;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Content;
using StardewModdingAPI.Framework.Content;
using StardewModdingAPI.Framework.ModLoading;
using StardewModdingAPI.Framework.Reflection;
using StardewModdingAPI.Framework.Utilities;
using StardewModdingAPI.Metadata;
using StardewValley;

namespace StardewModdingAPI.Framework
{
    /// <summary>SMAPI's implementation of the game's content manager which lets it raise content events.</summary>
    internal class SContentManager : LocalizedContentManager
    {
        /*********
        ** Properties
        *********/
        /// <summary>The possible directory separator characters in an asset key.</summary>
        private static readonly char[] PossiblePathSeparators = new[] { '/', '\\', Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar }.Distinct().ToArray();

        /// <summary>The preferred directory separator chaeacter in an asset key.</summary>
        private static readonly string PreferredPathSeparator = Path.DirectorySeparatorChar.ToString();

        /// <summary>Encapsulates monitoring and logging.</summary>
        private readonly IMonitor Monitor;

        /// <summary>The underlying content manager's asset cache.</summary>
        private readonly IDictionary<string, object> Cache;

        /// <summary>Applies platform-specific asset key normalisation so it's consistent with the underlying cache.</summary>
        private readonly Func<string, string> NormaliseAssetNameForPlatform;

        /// <summary>The private <see cref="LocalizedContentManager"/> method which generates the locale portion of an asset name.</summary>
        private readonly IPrivateMethod GetKeyLocale;

        /// <summary>The language codes used in asset keys.</summary>
        private readonly IDictionary<string, LanguageCode> KeyLocales;

        /// <summary>Provides metadata for core game assets.</summary>
        private readonly CoreAssets CoreAssets;

        /// <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>A lookup of the content managers which loaded each asset.</summary>
        private readonly IDictionary<string, HashSet<ContentManager>> AssetLoaders = new Dictionary<string, HashSet<ContentManager>>();


        /*********
        ** Accessors
        *********/
        /// <summary>Interceptors which provide the initial versions of matching assets.</summary>
        internal IDictionary<IModMetadata, IList<IAssetLoader>> Loaders { get; } = new Dictionary<IModMetadata, IList<IAssetLoader>>();

        /// <summary>Interceptors which edit matching assets after they're loaded.</summary>
        internal IDictionary<IModMetadata, IList<IAssetEditor>> Editors { get; } = new Dictionary<IModMetadata, IList<IAssetEditor>>();

        /// <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="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="languageCodeOverride">The current language code for which to localise content.</param>
        /// <param name="monitor">Encapsulates monitoring and logging.</param>
        public SContentManager(IServiceProvider serviceProvider, string rootDirectory, CultureInfo currentCulture, string languageCodeOverride, IMonitor monitor)
            : base(serviceProvider, rootDirectory, currentCulture, languageCodeOverride)
        {
            // validate
            if (monitor == null)
                throw new ArgumentNullException(nameof(monitor));

            // initialise
            var reflection = new Reflector();
            this.Monitor = monitor;

            // get underlying fields for interception
            this.Cache = reflection.GetPrivateField<Dictionary<string, object>>(this, "loadedAssets").GetValue();
            this.GetKeyLocale = reflection.GetPrivateMethod(this, "languageCode");

            // get asset key normalisation logic
            if (Constants.TargetPlatform == Platform.Windows)
            {
                IPrivateMethod method = reflection.GetPrivateMethod(typeof(TitleContainer), "GetCleanPath");
                this.NormaliseAssetNameForPlatform = path => method.Invoke<string>(path);
            }
            else
                this.NormaliseAssetNameForPlatform = key => key.Replace('\\', '/'); // based on MonoGame's ContentManager.Load<T> logic

            // get asset data
            this.CoreAssets = new CoreAssets(this.NormaliseAssetName);
            this.KeyLocales = this.GetKeyLocales(reflection);
        }

        /// <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>
        public string NormalisePathSeparators(string path)
        {
            string[] parts = path.Split(SContentManager.PossiblePathSeparators, StringSplitOptions.RemoveEmptyEntries);
            string normalised = string.Join(SContentManager.PreferredPathSeparator, parts);
            if (path.StartsWith(SContentManager.PreferredPathSeparator))
                normalised = SContentManager.PreferredPathSeparator + normalised; // keep root slash
            return normalised;
        }

        /// <summary>Normalise an asset name so it's consistent with the underlying cache.</summary>
        /// <param name="assetName">The asset key.</param>
        public string NormaliseAssetName(string assetName)
        {
            assetName = this.NormalisePathSeparators(assetName);
            if (assetName.EndsWith(".xnb", StringComparison.InvariantCultureIgnoreCase))
                return assetName.Substring(0, assetName.Length - 4);
            return this.NormaliseAssetNameForPlatform(assetName);
        }

        /// <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)
        {
            lock (this.Cache)
            {
                assetName = this.NormaliseAssetName(assetName);
                return this.IsNormalisedKeyLoaded(assetName);
            }
        }

        /// <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.LoadFor<T>(assetName, this);
        }

        /// <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="instance">The content manager instance for which to load the asset.</param>
        public T LoadFor<T>(string assetName, ContentManager instance)
        {
            lock (this.Cache)
            {
                assetName = this.NormaliseAssetName(assetName);

                // skip if already loaded
                if (this.IsNormalisedKeyLoaded(assetName))
                {
                    this.TrackAssetLoader(assetName, instance);
                    return base.Load<T>(assetName);
                }

                // 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);
                }
                else
                {
                    data = this.AssetsBeingLoaded.Track(assetName, () =>
                    {
                        IAssetInfo info = new AssetInfo(this.GetLocale(), assetName, typeof(T), this.NormaliseAssetName);
                        IAssetData asset = this.ApplyLoader<T>(info) ?? new AssetDataForObject(info, base.Load<T>(assetName), this.NormaliseAssetName);
                        asset = this.ApplyEditors<T>(info, asset);
                        return (T)asset.Data;
                    });
                }

                // update cache & return data
                this.Cache[assetName] = data;
                this.TrackAssetLoader(assetName, instance);
                return data;
            }
        }

        /// <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>