MegaBites-AI/Windows-powershell

1// Copyright (c) Microsoft Corporation.2// Licensed under the MIT License.3 4using System;5using System.Collections.Generic;6using System.Globalization;7using System.Management.Automation;8using System.Management.Automation.Internal;9 10namespace Microsoft.PowerShell.Commands.Internal.Format11{12    /// <summary>13    /// Internal class to manage the grouping algorithm for the14    /// format-xxx commands.15    /// </summary>16    internal sealed class GroupingInfoManager17    {18        /// <summary>19        /// Initialize with the grouping property data.20        /// </summary>21        /// <param name="groupingExpression">Name of the grouping property.</param>22        /// <param name="displayLabel">Display name of the property.</param>23        internal void Initialize(PSPropertyExpression groupingExpression, string displayLabel)24        {25            _groupingKeyExpression = groupingExpression;26            _label = displayLabel;27        }28 29        internal object CurrentGroupingKeyPropertyValue30        {31            get { return _currentGroupingKeyPropertyValue; }32        }33 34        internal string GroupingKeyDisplayName35        {36            get37            {38                if (_label != null)39                    return _label;40                return _groupingKeyDisplayName;41            }42        }43 44        /// <summary>45        /// Compute the string value of the grouping property.46        /// </summary>47        /// <param name="so">Object to use to compute the property value.</param>48        /// <returns>True if there was an update.</returns>49        internal bool UpdateGroupingKeyValue(PSObject so)50        {51            if (_groupingKeyExpression == null)52                return false;53 54            List<PSPropertyExpressionResult> results = _groupingKeyExpression.GetValues(so);55 56            // if we have more that one match, we have to select the first one57            if (results.Count > 0 && results[0].Exception == null)58            {59                // no exception got thrown, so we can update60                object newValue = results[0].Result;61                object oldValue = _currentGroupingKeyPropertyValue;62 63                _currentGroupingKeyPropertyValue = newValue;64 65                // now do the comparison66                bool update = !(IsEqual(_currentGroupingKeyPropertyValue, oldValue) ||67                                IsEqual(oldValue, _currentGroupingKeyPropertyValue));68 69                if (update && _label == null)70                {71                    _groupingKeyDisplayName = results[0].ResolvedExpression.ToString();72                }73 74                return update;75            }76 77            // we had no matches or we could not get the value:78            // NOTICE: we need to do this to avoid starting a new group every time79            // there is a failure to read the grouping property.80            // For example, for AD, there are objects that throw when trying81            // to read the "distinguishedName" property (used by the brokered property "ParentPath)82            return false;83        }84 85        private static bool IsEqual(object first, object second)86        {87            if (LanguagePrimitives.TryCompare(first, second, true, CultureInfo.CurrentCulture, out int result))88            {89                return result == 0;90            }91 92            // Note that this will occur if the objects do not support93            // IComparable.  We fall back to comparing as strings.94 95            // being here means the first object doesn't support ICompare96            // or an Exception was raised win Compare97            string firstString = PSObject.AsPSObject(first).ToString();98            string secondString = PSObject.AsPSObject(second).ToString();99 100            return string.Equals(firstString, secondString, StringComparison.CurrentCultureIgnoreCase);101        }102 103        /// <summary>104        /// Value of the display label passed in.105        /// </summary>106        private string _label = null;107 108        /// <summary>109        /// Value of the current active grouping key.110        /// </summary>111        private string _groupingKeyDisplayName = null;112 113        /// <summary>114        /// Name of the current grouping key.115        /// </summary>116        private PSPropertyExpression _groupingKeyExpression = null;117 118        /// <summary>119        /// The current value of the grouping key.120        /// </summary>121        private object _currentGroupingKeyPropertyValue = AutomationNull.Value;122    }123}124