use ConcurrentDictionary

Author: MarcoRossignoli

src/coverlet.core/Helpers/InstrumentationHelper.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
@@ -14,11 +15,11 @@ namespace Coverlet.Core.Helpers
 {
     internal static class InstrumentationHelper
     {
-        private static readonly Dictionary<string, string> _backupList = new Dictionary<string, string>();
+        private static readonly ConcurrentDictionary<string, string> _backupList = new ConcurrentDictionary<string, string>();
 
         static InstrumentationHelper()
         {
-            AppDomain.CurrentDomain.ProcessExit += (s,e) => RestoreOriginalModules();
+            AppDomain.CurrentDomain.ProcessExit += (s, e) => RestoreOriginalModules();
         }
 
         public static string[] GetCoverableModules(string module, string[] directories, bool includeTestAssembly)
@@ -94,13 +95,19 @@ public static void BackupOriginalModule(string module, string identifier)
             var backupPath = GetBackupPath(module, identifier);
             var backupSymbolPath = Path.ChangeExtension(backupPath, ".pdb");
             File.Copy(module, backupPath, true);
-            _backupList.Add(module, backupPath);
+            if (!_backupList.TryAdd(module, backupPath))
+            {
+                throw new ArgumentException($"Key already found '{module}'");
+            }
 
             var symbolFile = Path.ChangeExtension(module, ".pdb");
             if (File.Exists(symbolFile))
             {
                 File.Copy(symbolFile, backupSymbolPath, true);
-                _backupList.Add(symbolFile, backupSymbolPath);
+                if (!_backupList.TryAdd(symbolFile, backupSymbolPath))
+                {
+                    throw new ArgumentException($"Key already found '{module}'");
+                }
             }
         }
 
@@ -117,7 +124,7 @@ public static void RestoreOriginalModule(string module, string identifier)
             {
                 File.Copy(backupPath, module, true);
                 File.Delete(backupPath);
-                _backupList.Remove(module);
+                _backupList.TryRemove(module, out string _);
             }, retryStrategy, 10);
 
             RetryHelper.Retry(() =>
@@ -127,7 +134,7 @@ public static void RestoreOriginalModule(string module, string identifier)
                     string symbolFile = Path.ChangeExtension(module, ".pdb");
                     File.Copy(backupSymbolPath, symbolFile, true);
                     File.Delete(backupSymbolPath);
-                    _backupList.Remove(symbolFile);
+                    _backupList.TryRemove(symbolFile, out string _);
                 }
             }, retryStrategy, 10);
         }
@@ -145,7 +152,7 @@ public static void RestoreOriginalModules()
                 {
                     File.Copy(backupPath, key, true);
                     File.Delete(backupPath);
-                    _backupList.Remove(key);
+                    _backupList.TryRemove(key, out string _);
                 }, retryStrategy, 10);
             }
         }