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Redo command info cache changes
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+131
-50
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2 files changed

+131
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‎Engine/CommandInfoCache.cs

Lines changed: 119 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,119 @@
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// Copyright (c) Microsoft Corporation. All rights reserved.
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// Licensed under the MIT License.
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using System;
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using System.Collections.Concurrent;
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using System.Management.Automation;
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using System.Linq;
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namespace Microsoft.Windows.PowerShell.ScriptAnalyzer
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{
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/// <summary>
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/// Provides threadsafe caching around CommandInfo lookups with `Get-Command -Name ...`.
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/// </summary>
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internal class CommandInfoCache
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{
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private readonly ConcurrentDictionary<CommandLookupKey, Lazy<CommandInfo>> _commandInfoCache;
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private readonly Helper _helperInstance;
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/// <summary>
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/// Create a fresh command info cache instance.
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/// </summary>
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public CommandInfoCache(Helper pssaHelperInstance)
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{
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_commandInfoCache = new ConcurrentDictionary<CommandLookupKey, Lazy<CommandInfo>>();
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_helperInstance = pssaHelperInstance;
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}
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/// <summary>
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/// Retrieve a command info object about a command.
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/// </summary>
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/// <param name="commandName">Name of the command to get a commandinfo object for.</param>
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/// <param name="aliasName">The alias of the command to be used in the cache key. If not given, uses the command name.</param>
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/// <param name="commandTypes">What types of command are needed. If omitted, all types are retrieved.</param>
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/// <returns></returns>
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public CommandInfo GetCommandInfo(string commandName, string aliasName = null, CommandTypes? commandTypes = null)
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{
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if (string.IsNullOrWhiteSpace(commandName))
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{
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return null;
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}
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// If alias name is given, we store the entry under that, but search with the command name
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var key = new CommandLookupKey(aliasName ?? commandName, commandTypes);
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// Atomically either use PowerShell to query a command info object, or fetch it from the catch
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return _commandInfoCache.GetOrAdd(key, new Lazy<CommandInfo>(() => GetCommandInfoInternal(commandName, commandTypes))).Value;
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}
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/// <summary>
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/// Retrieve a command info object about a command.
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/// </summary>
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/// <param name="commandName">Name of the command to get a commandinfo object for.</param>
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/// <param name="commandTypes">What types of command are needed. If omitted, all types are retrieved.</param>
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/// <returns></returns>
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[Obsolete("Alias lookup is expensive and should not be relied upon for command lookup")]
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public CommandInfo GetCommandInfoLegacy(string commandOrAliasName, CommandTypes? commandTypes = null)
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{
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string commandName = _helperInstance.GetCmdletNameFromAlias(commandOrAliasName);
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return string.IsNullOrEmpty(commandName)
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? GetCommandInfo(commandOrAliasName, commandTypes: commandTypes)
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: GetCommandInfo(commandName, aliasName: commandOrAliasName, commandTypes: commandTypes);
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}
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/// <summary>
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/// Get a CommandInfo object of the given command name
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/// </summary>
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/// <returns>Returns null if command does not exists</returns>
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private static CommandInfo GetCommandInfoInternal(string cmdName, CommandTypes? commandType)
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{
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using (var ps = System.Management.Automation.PowerShell.Create())
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{
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ps.AddCommand("Get-Command")
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.AddParameter("Name", cmdName)
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.AddParameter("ErrorAction", "SilentlyContinue");
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if(commandType != null)
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{
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ps.AddParameter("CommandType", commandType);
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}
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return ps.Invoke<CommandInfo>()
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.FirstOrDefault();
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}
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}
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private struct CommandLookupKey : IEquatable<CommandLookupKey>
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{
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private readonly string Name;
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private readonly CommandTypes CommandTypes;
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internal CommandLookupKey(string name, CommandTypes? commandTypes)
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{
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Name = name;
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CommandTypes = commandTypes ?? CommandTypes.All;
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}
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public bool Equals(CommandLookupKey other)
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{
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return CommandTypes == other.CommandTypes
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&& Name.Equals(other.Name, StringComparison.OrdinalIgnoreCase);
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}
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public override int GetHashCode()
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{
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// Algorithm from https://stackoverflow.com/questions/1646807/quick-and-simple-hash-code-combinations
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unchecked
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{
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int hash = 17;
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hash = hash * 31 + Name.ToUpperInvariant().GetHashCode();
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hash = hash * 31 + CommandTypes.GetHashCode();
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return hash;
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}
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}
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}
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}
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}

‎Engine/Helper.cs

Lines changed: 12 additions & 50 deletions
Original file line numberDiff line numberDiff line change
@@ -24,11 +24,11 @@ public class Helper
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private CommandInvocationIntrinsics invokeCommand;
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private IOutputWriter outputWriter;
27-
private Object getCommandLock = new object();
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private readonly static Version minSupportedPSVersion = new Version(3, 0);
2928
private Dictionary<string, Dictionary<string, object>> ruleArguments;
3029
private PSVersionTable psVersionTable;
31-
private Dictionary<CommandLookupKey, CommandInfo> commandInfoCache;
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private readonly Lazy<CommandInfoCache> _commandInfoCacheLazy;
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#endregion
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@@ -100,14 +100,20 @@ internal set
100100
private string[] functionScopes = new string[] { "global:", "local:", "script:", "private:"};
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private string[] variableScopes = new string[] { "global:", "local:", "script:", "private:", "variable:", ":"};
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/// <summary>
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/// Store of command info objects for commands. Memoizes results.
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/// </summary>
107+
private CommandInfoCache CommandInfoCache => _commandInfoCacheLazy.Value;
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#endregion
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/// <summary>
106112
/// Initializes the Helper class.
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/// </summary>
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private Helper()
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{
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_commandInfoCacheLazy = new Lazy<CommandInfoCache>(() => new CommandInfoCache(pssaHelperInstance: this));
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}
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113119
/// <summary>
@@ -123,7 +129,7 @@ private Helper()
123129
/// </param>
124130
public Helper(
125131
CommandInvocationIntrinsics invokeCommand,
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IOutputWriter outputWriter)
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IOutputWriter outputWriter) : this()
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{
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this.invokeCommand = invokeCommand;
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this.outputWriter = outputWriter;
@@ -140,10 +146,6 @@ public void Initialize()
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KeywordBlockDictionary = new Dictionary<String, List<Tuple<int, int>>>(StringComparer.OrdinalIgnoreCase);
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VariableAnalysisDictionary = new Dictionary<Ast, VariableAnalysis>();
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ruleArguments = new Dictionary<string, Dictionary<string, object>>(StringComparer.OrdinalIgnoreCase);
143-
if (commandInfoCache == null)
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{
145-
commandInfoCache = new Dictionary<CommandLookupKey, CommandInfo>();
146-
}
147149

148150
IEnumerable<CommandInfo> aliases = this.invokeCommand.GetCommands("*", CommandTypes.Alias, true);
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@@ -676,7 +678,6 @@ private CommandInfo GetCommandInfoInternal(string cmdName, CommandTypes? command
676678
}
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678680
/// <summary>
679-
680681
/// Legacy method, new callers should use <see cref="GetCommandInfo"/> instead.
681682
/// Given a command's name, checks whether it exists. It does not use the passed in CommandTypes parameter, which is a bug.
682683
/// But existing method callers are already depending on this behaviour and therefore this could not be simply fixed.
@@ -688,30 +689,7 @@ private CommandInfo GetCommandInfoInternal(string cmdName, CommandTypes? command
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[Obsolete]
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public CommandInfo GetCommandInfoLegacy(string name, CommandTypes? commandType = null)
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{
691-
if (string.IsNullOrWhiteSpace(name))
692-
{
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return null;
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}
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696-
// check if it is an alias
697-
string cmdletName = Helper.Instance.GetCmdletNameFromAlias(name);
698-
if (string.IsNullOrWhiteSpace(cmdletName))
699-
{
700-
cmdletName = name;
701-
}
702-
703-
var key = new CommandLookupKey(name, commandType);
704-
lock (getCommandLock)
705-
{
706-
if (commandInfoCache.ContainsKey(key))
707-
{
708-
return commandInfoCache[key];
709-
}
710-
711-
var commandInfo = GetCommandInfoInternal(cmdletName, commandType);
712-
commandInfoCache.Add(key, commandInfo);
713-
return commandInfo;
714-
}
692+
return CommandInfoCache.GetCommandInfoLegacy(commandOrAliasName: name, commandTypes: commandType);
715693
}
716694

717695
/// <summary>
@@ -722,23 +700,7 @@ public CommandInfo GetCommandInfoLegacy(string name, CommandTypes? commandType =
722700
/// <returns></returns>
723701
public CommandInfo GetCommandInfo(string name, CommandTypes? commandType = null)
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{
725-
if (string.IsNullOrWhiteSpace(name))
726-
{
727-
return null;
728-
}
729-
730-
var key = new CommandLookupKey(name, commandType);
731-
lock (getCommandLock)
732-
{
733-
if (commandInfoCache.ContainsKey(key))
734-
{
735-
return commandInfoCache[key];
736-
}
737-
738-
var commandInfo = GetCommandInfoInternal(name, commandType);
739-
commandInfoCache.Add(key, commandInfo);
740-
return commandInfo;
741-
}
703+
return CommandInfoCache.GetCommandInfo(name, commandTypes: commandType);
742704
}
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744706
/// <summary>

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