From a281d3d971e8a89bb6b52043c62fef6e12c2d2f7 Mon Sep 17 00:00:00 2001
From: Jason Shirk <jasonsh@microsoft.com>
Date: Sun, 14 Jul 2019 14:49:45 -0700
Subject: [PATCH] Faster pipeline binding for ForEach-Object

---
 .../engine/CommandDiscovery.cs                | 13 +++++---
 .../engine/CommandProcessor.cs                | 31 ++++++++++++++++++-
 .../engine/CommandProcessorBase.cs            |  7 -----
 3 files changed, 39 insertions(+), 12 deletions(-)

diff --git a/src/System.Management.Automation/engine/CommandDiscovery.cs b/src/System.Management.Automation/engine/CommandDiscovery.cs
index d5c639430cf..4fb8345e142 100644
--- a/src/System.Management.Automation/engine/CommandDiscovery.cs
+++ b/src/System.Management.Automation/engine/CommandDiscovery.cs
@@ -529,9 +529,6 @@ private static string BuildPSSnapInDisplayName(PSSnapInSpecification PSSnapin)
         /// <param name="sessionState">The session state the commandInfo should be run in.</param>
         /// <returns>
         /// </returns>
-        /// <exception cref="CommandNotFoundException">
-        /// If the command, <paramref name="commandName"/>, could not be found.
-        /// </exception>
         /// <exception cref="System.Management.Automation.PSSecurityException">
         /// If the security manager is preventing the command from running.
         /// </exception>
@@ -575,7 +572,15 @@ internal CommandProcessorBase LookupCommandProcessor(CommandInfo commandInfo,
                     processor = new NativeCommandProcessor((ApplicationInfo)commandInfo, Context);
                     break;
                 case CommandTypes.Cmdlet:
-                    processor = new CommandProcessor((CmdletInfo)commandInfo, Context);
+                    var cmdletInfo = (CmdletInfo)commandInfo;
+                    if (cmdletInfo.ImplementingType == typeof(ForEachObjectCommand))
+                    {
+                        processor = new SimpleForEachObjectCommandProcessor(cmdletInfo, Context);
+                    }
+                    else
+                    {
+                        processor = new CommandProcessor(cmdletInfo, Context);
+                    }
                     break;
                 case CommandTypes.ExternalScript:
                     ExternalScriptInfo scriptInfo = (ExternalScriptInfo)commandInfo;
diff --git a/src/System.Management.Automation/engine/CommandProcessor.cs b/src/System.Management.Automation/engine/CommandProcessor.cs
index 40fb3eff83f..203f32bcda7 100644
--- a/src/System.Management.Automation/engine/CommandProcessor.cs
+++ b/src/System.Management.Automation/engine/CommandProcessor.cs
@@ -83,6 +83,16 @@ internal CommandProcessor(IScriptCommandInfo scriptCommandInfo, ExecutionContext
             Init(scriptCommandInfo);
         }
 
+        protected CommandProcessor(CmdletInfo cmdletInfo, ExecutionContext context, ForEachObjectCommand instance)
+            : base(cmdletInfo)
+        {
+            this._context = context;
+            this.Command = instance;
+            this.CommandScope = Context.EngineSessionState.CurrentScope;
+
+            InitCommon();
+        }
+
         #endregion ctor
 
         #region internal members
@@ -663,7 +673,12 @@ private bool ProcessInputPipelineObject(object inputObject)
 
             Command.CurrentPipelineObject = inputToOperateOn;
 
-            return this.CmdletParameterBinderController.BindPipelineParameters(inputToOperateOn);
+            return this.BindPipelineParameters(inputToOperateOn);
+        }
+
+        protected virtual bool BindPipelineParameters(PSObject inputObject)
+        {
+            return this.CmdletParameterBinderController.BindPipelineParameters(inputObject);
         }
 
         private static readonly ConcurrentDictionary<Type, Func<Cmdlet>> s_constructInstanceCache;
@@ -868,5 +883,19 @@ internal override bool IsHelpRequested(out string helpTarget, out HelpCategory h
 
         #endregion helper_methods
     }
+
+    internal class SimpleForEachObjectCommandProcessor : CommandProcessor
+    {
+        internal SimpleForEachObjectCommandProcessor(CmdletInfo cmdletInfo, ExecutionContext context)
+            : base(cmdletInfo, context, new ForEachObjectCommand())
+        {
+        }
+
+        protected override bool BindPipelineParameters(PSObject inputObject)
+        {
+            ((ForEachObjectCommand)this.Command).InputObject = inputObject;
+            return true;
+        }
+    }
 }
 
diff --git a/src/System.Management.Automation/engine/CommandProcessorBase.cs b/src/System.Management.Automation/engine/CommandProcessorBase.cs
index 042a69489ca..38bb37ed86c 100644
--- a/src/System.Management.Automation/engine/CommandProcessorBase.cs
+++ b/src/System.Management.Automation/engine/CommandProcessorBase.cs
@@ -18,13 +18,6 @@ internal abstract class CommandProcessorBase : IDisposable
     {
         #region ctor
 
-        /// <summary>
-        /// Default constructor.
-        /// </summary>
-        internal CommandProcessorBase()
-        {
-        }
-
         /// <summary>
         /// Initializes the base command processor class with the command metadata.
         /// </summary>