rewrite mod assembly loading (#229)

This greatly simplifies mod loading, eliminates the .cache folders by loading assemblies in memory, ensures DLLs are loaded in leaf-to-root order, and reduces log verbosity. These changes should address a range of issues, notably #221 and #226.

1 files changed, 61 insertions, 0 deletions

diff --git a/src/StardewModdingAPI/Framework/AssemblyDefinitionResolver.cs b/src/StardewModdingAPI/Framework/AssemblyDefinitionResolver.cs
new file mode 100644
index 00000000..b4e69fcd
--- /dev/null
+++ b/src/StardewModdingAPI/Framework/AssemblyDefinitionResolver.cs
@@ -0,0 +1,61 @@
+using System.Collections.Generic;
+using Mono.Cecil;
+
+namespace StardewModdingAPI.Framework
+{
+    /// <summary>A minimal assembly definition resolver which resolves references to known assemblies.</summary>
+    internal class AssemblyDefinitionResolver : DefaultAssemblyResolver
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>The known assemblies.</summary>
+        private readonly IDictionary<string, AssemblyDefinition> Loaded = new Dictionary<string, AssemblyDefinition>();
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Add known assemblies to the resolver.</summary>
+        /// <param name="assemblies">The known assemblies.</param>
+        public void Add(params AssemblyDefinition[] assemblies)
+        {
+            foreach (AssemblyDefinition assembly in assemblies)
+            {
+                this.Loaded[assembly.Name.Name] = assembly;
+                this.Loaded[assembly.Name.FullName] = assembly;
+            }
+        }
+
+        /// <summary>Resolve an assembly reference.</summary>
+        /// <param name="name">The assembly name.</param>
+        public override AssemblyDefinition Resolve(AssemblyNameReference name) => this.ResolveName(name.Name) ?? base.Resolve(name);
+
+        /// <summary>Resolve an assembly reference.</summary>
+        /// <param name="name">The assembly name.</param>
+        /// <param name="parameters">The assembly reader parameters.</param>
+        public override AssemblyDefinition Resolve(AssemblyNameReference name, ReaderParameters parameters) => this.ResolveName(name.Name) ?? base.Resolve(name, parameters);
+
+        /// <summary>Resolve an assembly reference.</summary>
+        /// <param name="fullName">The assembly full name (including version, etc).</param>
+        public override AssemblyDefinition Resolve(string fullName) => this.ResolveName(fullName) ?? base.Resolve(fullName);
+
+        /// <summary>Resolve an assembly reference.</summary>
+        /// <param name="fullName">The assembly full name (including version, etc).</param>
+        /// <param name="parameters">The assembly reader parameters.</param>
+        public override AssemblyDefinition Resolve(string fullName, ReaderParameters parameters) => this.ResolveName(fullName) ?? base.Resolve(fullName, parameters);
+
+
+        /*********
+        ** Private methods
+        *********/
+        /// <summary>Resolve a known assembly definition based on its short or full name.</summary>
+        /// <param name="name">The assembly's short or full name.</param>
+        private AssemblyDefinition ResolveName(string name)
+        {
+            return this.Loaded.ContainsKey(name)
+                ? this.Loaded[name]
+                : null;
+        }
+    }
+}