Merge pull request #1074 from SeeminglyScience/reenable-command-caching

Restore caching in Helper.GetCommandInfo

Author: JamesWTruher

Engine/CommandLookupKey.cs

@@ -0,0 +1,39 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System;
+using System.Management.Automation;
+
+namespace Microsoft.Windows.PowerShell.ScriptAnalyzer
+{
+    internal struct CommandLookupKey : IEquatable<CommandLookupKey>
+    {
+        private readonly string Name;
+
+        private readonly CommandTypes CommandTypes;
+
+        internal CommandLookupKey(string name, CommandTypes? commandTypes)
+        {
+            Name = name;
+            CommandTypes = commandTypes ?? CommandTypes.All;
+        }
+
+        public bool Equals(CommandLookupKey other)
+        {
+            return CommandTypes == other.CommandTypes
+                && Name.Equals(other.Name, StringComparison.OrdinalIgnoreCase);
+        }
+
+        public override int GetHashCode()
+        {
+            // Algorithm from https://stackoverflow.com/questions/1646807/quick-and-simple-hash-code-combinations
+            unchecked
+            {
+                int hash = 17;
+                hash = hash * 31 + Name.ToUpperInvariant().GetHashCode();
+                hash = hash * 31 + CommandTypes.GetHashCode();
+                return hash;
+            }
+        }
+    }
+}

Engine/Helper.cs

@@ -28,7 +28,7 @@ public class Helper
         private readonly static Version minSupportedPSVersion = new Version(3, 0);
         private Dictionary<string, Dictionary<string, object>> ruleArguments;
         private PSVersionTable psVersionTable;
-        private Dictionary<string, CommandInfo> commandInfoCache;
+        private Dictionary<CommandLookupKey, CommandInfo> commandInfoCache;
 
         #endregion
 
@@ -142,7 +142,7 @@ public void Initialize()
             ruleArguments = new Dictionary<string, Dictionary<string, object>>(StringComparer.OrdinalIgnoreCase);
             if (commandInfoCache == null)
             {
-                commandInfoCache = new Dictionary<string, CommandInfo>(StringComparer.OrdinalIgnoreCase);
+                commandInfoCache = new Dictionary<CommandLookupKey, CommandInfo>();
             }
 
             IEnumerable<CommandInfo> aliases = this.invokeCommand.GetCommands("*", CommandTypes.Alias, true);
@@ -700,15 +700,16 @@ public CommandInfo GetCommandInfoLegacy(string name, CommandTypes? commandType =
                 cmdletName = name;
             }
 
+            var key = new CommandLookupKey(name, commandType);
             lock (getCommandLock)
             {
-                if (commandInfoCache.ContainsKey(cmdletName))
+                if (commandInfoCache.ContainsKey(key))
                 {
-                    return commandInfoCache[cmdletName];
+                    return commandInfoCache[key];
                 }
 
                 var commandInfo = GetCommandInfoInternal(cmdletName, commandType);
-                commandInfoCache.Add(cmdletName, commandInfo);
+                commandInfoCache.Add(key, commandInfo);
                 return commandInfo;
             }
         }
@@ -726,15 +727,16 @@ public CommandInfo GetCommandInfo(string name, CommandTypes? commandType = null)
                 return null;
             }
 
+            var key = new CommandLookupKey(name, commandType);
             lock (getCommandLock)
             {
-                if (commandInfoCache.ContainsKey(name))
+                if (commandInfoCache.ContainsKey(key))
                 {
-                    return commandInfoCache[name];
+                    return commandInfoCache[key];
                 }
 
                 var commandInfo = GetCommandInfoInternal(name, commandType);
-
+                commandInfoCache.Add(key, commandInfo);
                 return commandInfo;
             }
         }