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

using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Diagnostics.Contracts;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Threading;
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 StardewModdingAPI.Metadata;
using StardewValley;

namespace StardewModdingAPI.Framework
{
    /// <summary>A thread-safe content manager which intercepts assets being loaded to let SMAPI mods inject or edit them.</summary>
    /// <remarks>
    /// This is the centralised content manager which manages all game assets. The game and mods don't use this class
    /// directly; instead they use one of several <see cref="ContentManagerShim"/> instances, which proxy requests to
    /// this class. That ensures that when the game disposes one content manager, the others can continue unaffected.
    /// That notably requires this class to be thread-safe, since the content managers can be disposed asynchronously.
    /// 
    /// Note that assets in the cache have two identifiers: the asset name (like "bundles") and key (like "bundles.pt-BR").
    /// For English and non-translatable assets, these have the same value. The underlying cache only knows about asset
    /// keys, and the game and mods only know about asset names. The content manager handles resolving them.
    /// </remarks>
    internal class SContentManager : LocalizedContentManager
    {
        /*********
        ** Properties
        *********/
        /// <summary>Encapsulates monitoring and logging.</summary>
        private readonly IMonitor Monitor;

        /// <summary>The underlying asset cache.</summary>
        private readonly ContentCache Cache;

        /// <summary>The private <see cref="LocalizedContentManager"/> method which generates the locale portion of an asset name.</summary>
        private readonly IReflectedMethod 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>> ContentManagersByAssetKey = new Dictionary<string, HashSet<ContentManager>>();

        /// <summary>The path prefix for assets in mod folders.</summary>
        private readonly string ModContentPrefix;

        /// <summary>A lock used to prevents concurrent changes to the cache while data is being read.</summary>
        private readonly ReaderWriterLockSlim Lock = new ReaderWriterLockSlim(LockRecursionPolicy.SupportsRecursion);


        /*********
        ** 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>
        internal string FullRootDirectory => Path.Combine(Constants.ExecutionPath, this.RootDirectory);


        /*********
        ** Public methods
        *********/
        /****
        ** Constructor
        ****/
        /// <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>
        /// <param name="reflection">Simplifies access to private code.</param>
        public SContentManager(IServiceProvider serviceProvider, string rootDirectory, CultureInfo currentCulture, string languageCodeOverride, IMonitor monitor, Reflector reflection)
            : base(serviceProvider, rootDirectory, currentCulture, languageCodeOverride)
        {
            // init
            this.Monitor = monitor ?? throw new ArgumentNullException(nameof(monitor));
            this.Cache = new ContentCache(this, reflection);
            this.GetKeyLocale = reflection.GetMethod(this, "languageCode");
            this.ModContentPrefix = this.GetAssetNameFromFilePath(Constants.ModPath);

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

        /****
        ** Asset key/name handling
        ****/
        /// <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="ArgumentException">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)
        {
            if (string.IsNullOrWhiteSpace(key))
                throw new ArgumentException("The asset key or local path is empty.");
            if (key.Intersect(Path.GetInvalidPathChars()).Any())
                throw new ArgumentException("The asset key or local path contains invalid characters.");
        }

        /// <summary>Convert an absolute file path into a appropriate asset name.</summary>
        /// <param name="absolutePath">The absolute path to the file.</param>
        public string GetAssetNameFromFilePath(string absolutePath)
        {
#if SMAPI_FOR_WINDOWS
            // XNA doesn't allow absolute asset paths, so get a path relative to the content folder
            return this.GetRelativePath(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.GetKeyLocale.Invoke<string>();
        }

        /// <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.WithReadLock(() => this.IsNormalisedKeyLoaded(assetName));
        }

        /// <summary>Get the cached asset keys.</summary>
        public IEnumerable<string> GetAssetKeys()
        {
            return this.WithReadLock(() =>
                this.Cache.Keys
                    .Select(this.GetAssetName)
                    .Distinct()
            );
        }

        /// <summary>Load an asset through the content pipeline. When loading a <c>.png</c> file, this must be called outside the game's draw loop.</summary>
        /// <typeparam name="T">The expected asset type.</typeparam>
        /// <param name="assetName">The asset path relative to the content directory.</param>
        public override T Load<T>(string assetName)
        {
            return this.LoadFor<T>(assetName, this);
        <