Cache assembly fetches/resolution so that repeat errors aren't clogging the log

Source/LibationFileManager/InteropFactory.cs

@@ -80,53 +80,71 @@ namespace LibationFileManager
             return appName;
         }
 
-       /*
+        /*
-        * Use this method to locate dependencies when they are not in Libation's program files directory.
+         * Use this method to locate dependencies when they are not in Libation's program files directory.
-        * 
+         * 
-        private static List<ProcessModule> LoadModuleList(string exeName)
+         private static List<ProcessModule> LoadModuleList(string exeName)
-        {
+         {
-            var proc = new Process
+             var proc = new Process
-            {
+             {
-                StartInfo = new()
+                 StartInfo = new()
-                {
+                 {
-                    FileName = exeName,
+                     FileName = exeName,
-                    RedirectStandardInput = true,
+                     RedirectStandardInput = true,
-                    RedirectStandardOutput = true,
+                     RedirectStandardOutput = true,
-                    CreateNoWindow = true,
+                     CreateNoWindow = true,
-                    WindowStyle = ProcessWindowStyle.Hidden,
+                     WindowStyle = ProcessWindowStyle.Hidden,
-                    UseShellExecute = false
+                     UseShellExecute = false
-                }
+                 }
-            };
+             };
 
-            var waitHandle = new EventWaitHandle(false, EventResetMode.ManualReset);
+             var waitHandle = new EventWaitHandle(false, EventResetMode.ManualReset);
 
-            proc.OutputDataReceived += (_, _) => waitHandle.Set();
+             proc.OutputDataReceived += (_, _) => waitHandle.Set();
-            proc.Start();
+             proc.Start();
-            proc.BeginOutputReadLine();
+             proc.BeginOutputReadLine();
 
-            //Let the win process know we're ready to receive its standard output
+             //Let the win process know we're ready to receive its standard output
-            proc.StandardInput.WriteLine();
+             proc.StandardInput.WriteLine();
 
-            if (!waitHandle.WaitOne(2000))
+             if (!waitHandle.WaitOne(2000))
-                throw new Exception("Failed to start program");
+                 throw new Exception("Failed to start program");
 
-            //The win process has finished loading and is now waiting inside Main().
+             //The win process has finished loading and is now waiting inside Main().
-            //Copy it process module list.
+             //Copy it process module list.
-            var modules = proc.Modules.Cast<ProcessModule>().ToList();
+             var modules = proc.Modules.Cast<ProcessModule>().ToList();
 
-            //Let the win process know we're done reading its module list
+             //Let the win process know we're done reading its module list
-            proc.StandardInput.WriteLine();
+             proc.StandardInput.WriteLine();
 
-            return modules;
+             return modules;
-        }
+         }
-        */
+         */
 
+        private static Dictionary<string, Assembly> lowEffortCache { get; } = new();
         private static Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
         {
             // e.g. "System.Windows.Forms, Version=6.0.2.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
             var asmName = args.Name.Split(',')[0] + ".dll";
+            var here = Path.GetDirectoryName(Environment.ProcessPath);
 
+            var key = $"{asmName}|{here}";
 
+            if (lowEffortCache.TryGetValue(key, out var value))
+                return value;
+
+            var assembly = CurrentDomain_AssemblyResolve_internal(asmName: asmName, here: here);
+            lowEffortCache[key] = assembly;
+
+            //Let the runtime handle any dll not found exceptions.
+            if (assembly is null)
+                Serilog.Log.Logger.Error($"Unable to load module {args.Name}");
+
+            return assembly;
+        }
+
+        private static Assembly CurrentDomain_AssemblyResolve_internal(string asmName, string here)
+        {
             /*
              * Commented code used to locate assemblies from the *ConfigApp.exe's module list.
              * Use this method to locate dependencies when they are not in Libation's program files directory.
@@ -135,20 +153,15 @@ namespace LibationFileManager
             var modulePath = ModuleList.SingleOrDefault(m => m.ModuleName.EqualsInsensitive(asmName))?.FileName;
  #else
             */
-            var here = Path.GetDirectoryName(Environment.ProcessPath);
 
             // find the requested assembly in the program files directory
             var modulePath =
                 Directory.EnumerateFiles(here, asmName, SearchOption.TopDirectoryOnly)
                 .SingleOrDefault();
 
-            //#endif
+//#endif
             if (modulePath is null)
-            {
-                //Let the runtime handle any dll not found exceptions.
-                Serilog.Log.Logger.Error($"Unable to load module {args.Name}");
                 return null;
-            }
 
             return Assembly.LoadFrom(modulePath);
         }