preprocess all mod assemblies for compatibility with multi-assembly mods (#166)

2 files changed, 94 insertions, 22 deletions

diff --git a/src/StardewModdingAPI/Framework/ModAssemblyLoader.cs b/src/StardewModdingAPI/Framework/ModAssemblyLoader.cs
index 2615e1f7..6c0f0cdf 100644
--- a/src/StardewModdingAPI/Framework/ModAssemblyLoader.cs
+++ b/src/StardewModdingAPI/Framework/ModAssemblyLoader.cs
@@ -1,4 +1,5 @@
-using System.IO;
+using System;
+using System.IO;
 using System.Linq;
 using System.Reflection;
 using System.Security.Cryptography;
@@ -6,7 +7,7 @@ using Mono.Cecil;
 
 namespace StardewModdingAPI.Framework
 {
-    /// <summary>Loads mod assemblies.</summary>
+    /// <summary>Preprocesses and loads mod assemblies.</summary>
     internal class ModAssemblyLoader
     {
         /*********
@@ -26,19 +27,17 @@ namespace StardewModdingAPI.Framework
             this.CacheDirPath = cacheDirPath;
         }
 
-        /// <summary>Read an assembly from the given path.</summary>
+        /// <summary>Preprocess an assembly and cache the modified version.</summary>
         /// <param name="assemblyPath">The assembly file path.</param>
-        public Assembly ProcessAssembly(string assemblyPath)
+        public void ProcessAssembly(string assemblyPath)
         {
             // read assembly data
             byte[] assemblyBytes = File.ReadAllBytes(assemblyPath);
             byte[] hash = MD5.Create().ComputeHash(assemblyBytes);
 
-            // get cache data
-            string key = Path.GetFileNameWithoutExtension(assemblyPath);
-            string cachePath = Path.Combine(this.CacheDirPath, $"{key}.dll");
-            string cacheHashPath = Path.Combine(this.CacheDirPath, $"{key}-hash.txt");
-            bool canUseCache = File.Exists(cachePath) && File.Exists(cacheHashPath) && hash.SequenceEqual(File.ReadAllBytes(cacheHashPath));
+            // check cache
+            CachePaths cachePaths = this.GetCacheInfo(assemblyPath);
+            bool canUseCache = File.Exists(cachePaths.Assembly) && File.Exists(cachePaths.Hash) && hash.SequenceEqual(File.ReadAllBytes(cachePaths.Hash));
 
             // process assembly if not cached
             if (!canUseCache)
@@ -53,13 +52,70 @@ namespace StardewModdingAPI.Framework
                 {
                     definition.Write(outStream);
                     byte[] outBytes = outStream.ToArray();
-                    File.WriteAllBytes(cachePath, outBytes);
-                    File.WriteAllBytes(cacheHashPath, hash);
+                    Directory.CreateDirectory(cachePaths.Directory);
+                    File.WriteAllBytes(cachePaths.Assembly, outBytes);
+                    File.WriteAllBytes(cachePaths.Hash, hash);
                 }
             }
+        }
+
+        /// <summary>Load a preprocessed assembly.</summary>
+        /// <param name="assemblyPath">The assembly file path.</param>
+        public Assembly LoadCachedAssembly(string assemblyPath)
+        {
+            CachePaths cachePaths = this.GetCacheInfo(assemblyPath);
+            if (!File.Exists(cachePaths.Assembly))
+                throw new InvalidOperationException($"The assembly {assemblyPath} doesn't exist in the preprocessed cache.");
+            return Assembly.UnsafeLoadFrom(cachePaths.Assembly);
+        }
 
-            // load assembly
-            return Assembly.UnsafeLoadFrom(cachePath);
+
+        /*********
+        ** Private methods
+        *********/
+        /// <summary>Get the cache details for an assembly.</summary>
+        /// <param name="assemblyPath">The assembly file path.</param>
+        private CachePaths GetCacheInfo(string assemblyPath)
+        {
+            string key = Path.GetFileNameWithoutExtension(assemblyPath);
+            string dirPath = Path.Combine(this.CacheDirPath, new DirectoryInfo(Path.GetDirectoryName(assemblyPath)).Name);
+            string cacheAssemblyPath = Path.Combine(dirPath, $"{key}.dll");
+            string cacheHashPath = Path.Combine(dirPath, $"{key}.hash");
+            return new CachePaths(dirPath, cacheAssemblyPath, cacheHashPath);
+        }
+
+        /*********
+        ** Private objects
+        *********/
+        /// <summary>Contains the paths for an assembly's cached data.</summary>
+        private struct CachePaths
+        {
+            /*********
+            ** Accessors
+            *********/
+            /// <summary>The directory path which contains the assembly.</summary>
+            public string Directory { get; }
+
+            /// <summary>The file path of the assembly file.</summary>
+            public string Assembly { get; }
+
+            /// <summary>The file path containing the MD5 hash for the assembly.</summary>
+            public string Hash { get; }
+
+
+            /*********
+            ** Public methods
+            *********/
+            /// <summary>Construct an instance.</summary>
+            /// <param name="directory">The directory path which contains the assembly.</param>
+            /// <param name="assembly">The file path of the assembly file.</param>
+            /// <param name="hash">The file path containing the MD5 hash for the assembly.</param>
+            public CachePaths(string directory, string assembly, string hash)
+            {
+                this.Directory = directory;
+                this.Assembly = assembly;
+                this.Hash = hash;
+            }
         }
     }
 }
diff --git a/src/StardewModdingAPI/Program.cs b/src/StardewModdingAPI/Program.cs
index 255ad365..f8920896 100644
--- a/src/StardewModdingAPI/Program.cs
+++ b/src/StardewModdingAPI/Program.cs
@@ -301,6 +301,10 @@ namespace StardewModdingAPI
             ModAssemblyLoader modAssemblyLoader = new ModAssemblyLoader(Program.CachePath);
             foreach (string directory in Directory.GetDirectories(Program.ModPath))
             {
+                // ignore internal directory
+                if (new DirectoryInfo(directory).Name == ".cache")
+                    continue;
+
                 // check for cancellation
                 if (Program.CancellationTokenSource.IsCancellationRequested)
                 {
@@ -388,20 +392,32 @@ namespace StardewModdingAPI
                     }
                 }
 
+                // preprocess mod assemblies
+                {
+                    bool succeeded = true;
+                    foreach (string assemblyPath in Directory.GetFiles(directory, "*.dll"))
+                    {
+                        try
+                        {
+                            modAssemblyLoader.ProcessAssembly(assemblyPath);
+                        }
+                        catch (Exception ex)
+                        {
+                            Program.Monitor.Log($"{errorPrefix}: an error occurred while preprocessing '{assemblyPath}'.\n{ex}", LogLevel.Error);
+                            succeeded = false;
+                            break;
+                        }
+                    }
+                    if (!succeeded)
+                        continue;
+                }
+
                 // load assembly
                 Assembly modAssembly;
                 try
                 {
-                    // get assembly path
                     string assemblyPath = Path.Combine(directory, manifest.EntryDll);
-                    if (!File.Exists(assemblyPath))
-                    {
-                        Program.Monitor.Log($"{errorPrefix}: target DLL '{assemblyPath}' does not exist.", LogLevel.Error);
-                        continue;
-                    }
-
-                    // read assembly
-                    modAssembly = modAssemblyLoader.ProcessAssembly(assemblyPath);
+                    modAssembly = modAssemblyLoader.LoadCachedAssembly(assemblyPath);
                     if (modAssembly.DefinedTypes.Count(x => x.BaseType == typeof(Mod)) == 0)
                     {
                         Program.Monitor.Log($"{errorPrefix}: the mod DLL does not contain an implementation of the 'Mod' class.", LogLevel.Error);