fix library setup restart when interrupted

Author: amakropoulos

Runtime/LLMUnitySetup.cs

@@ -366,24 +366,18 @@ static async Task DownloadAndExtractInsideDirectory(string url, string path, str
 
         static async Task DownloadLibrary()
         {
-            void DeleteFileAndMeta(string path)
-            {
-                if (File.Exists(path + ".meta")) File.Delete(path + ".meta");
-                if (File.Exists(path)) File.Delete(path);
-            }
+            if (libraryProgress < 1) return;
+            libraryProgress = 0;
 
             try
             {
                 string setupDir = Path.Combine(libraryPath, "setup");
                 Directory.CreateDirectory(setupDir);
 
-                string lockFile = Path.Combine(setupDir, "LLMUnitySetup.lock");
-                if (File.Exists(lockFile)) return;
-                CreateEmptyFile(lockFile);
-
-                libraryProgress = 0;
+                // setup LlamaLib in StreamingAssets
                 await DownloadAndExtractInsideDirectory(LlamaLibURL, libraryPath, setupDir);
 
+                // setup LlamaLib in Plugins for Android
                 AssetDatabase.StartAssetEditing();
                 string androidDir = Path.Combine(libraryPath, "android");
                 if (Directory.Exists(androidDir))
@@ -397,15 +391,15 @@ void DeleteFileAndMeta(string path)
                 }
                 AssetDatabase.StopAssetEditing();
 
+                // setup LlamaLib extras in StreamingAssets
                 if (FullLlamaLib) await DownloadAndExtractInsideDirectory(LlamaLibExtensionURL, libraryPath, setupDir);
-
-                libraryProgress = 1;
-                DeleteFileAndMeta(lockFile);
             }
             catch (Exception e)
             {
                 LogError(e.Message);
             }
+
+            libraryProgress = 1;
         }
 
         private static void SetLibraryProgress(float progress)