MegaBites-AI/Windows-powershell

1// Copyright (c) Microsoft Corporation.2// Licensed under the MIT License.3 4using System.Collections.ObjectModel;5 6using Dbg = System.Management.Automation;7 8namespace System.Management.Automation9{10    /// <summary>11    /// A collection of the attributes on the PSVariable object.12    /// </summary>13    internal class PSVariableAttributeCollection : Collection<Attribute>14    {15        #region constructor16 17        /// <summary>18        /// Constructs a variable attribute collection attached to19        /// the specified variable. Whenever the attributes change20        /// the variable value is verified against the attribute.21        /// </summary>22        /// <param name="variable">23        /// The variable that needs to be verified anytime an attribute24        /// changes.25        /// </param>26        /// <exception cref="ArgumentNullException">27        /// If <paramref name="variable"/> is null.28        /// </exception>29        internal PSVariableAttributeCollection(PSVariable variable)30        {31            if (variable == null)32            {33                throw PSTraceSource.NewArgumentNullException(nameof(variable));34            }35 36            _variable = variable;37        }38        #endregion constructor39 40        #region Collection overrides41 42        /// <summary>43        /// Ensures that the variable that the attribute is being added to is still44        /// valid after the attribute is added.45        /// </summary>46        /// <param name="index">47        /// The zero-based index at which <paramref name="item"/> should be inserted.48        /// </param>49        /// <param name="item">50        /// The attribute being added to the collection.51        /// </param>52        /// <exception cref="ValidationMetadataException">53        /// If the new attribute causes the variable to be in an invalid state.54        /// </exception>55        /// <exception cref="ArgumentTransformationMetadataException">56        /// If the new attribute is an ArgumentTransformationAttribute and the transformation57        /// fails.58        /// </exception>59        protected override void InsertItem(int index, Attribute item)60        {61            object variableValue = VerifyNewAttribute(item);62 63            base.InsertItem(index, item);64 65            _variable.SetValueRaw(variableValue, true);66        }67 68        /// <summary>69        /// Ensures that the variable that the attribute is being set to is still70        /// valid after the attribute is set.71        /// </summary>72        /// <param name="index">73        /// The zero-based index at which <paramref name="item"/> should be set.74        /// </param>75        /// <param name="item">76        /// The attribute being set in the collection.77        /// </param>78        /// <exception cref="ValidationMetadataException">79        /// If the new attribute causes the variable to be in an invalid state.80        /// </exception>81        protected override void SetItem(int index, Attribute item)82        {83            object variableValue = VerifyNewAttribute(item);84 85            base.SetItem(index, item);86 87            _variable.SetValueRaw(variableValue, true);88        }89        #endregion Collection overrides90 91        #region private data92 93        /// <summary>94        /// Ordinarily, the collection checks/converts the value (by applying the attribute)95        /// when an attribute is added.  This is both slow and wrong when the attributes96        /// have already been checked/applied during parameter binding.  So if checking97        /// has already been done, this function will add the attribute without checking98        /// and possibly updating the value.99        /// </summary>100        /// <param name="item">The attribute to add.</param>101        internal void AddAttributeNoCheck(Attribute item)102        {103            base.InsertItem(this.Count, item);104        }105 106        /// <summary>107        /// Validates and performs any transformations that the new attribute108        /// implements.109        /// </summary>110        /// <param name="item">111        /// The new attribute to be added to the collection.112        /// </param>113        /// <returns>114        /// The new variable value. This may change from the original value if the115        /// new attribute is an ArgumentTransformationAttribute.116        /// </returns>117        private object VerifyNewAttribute(Attribute item)118        {119            object variableValue = _variable.Value;120 121            // Perform transformation before validating122            ArgumentTransformationAttribute argumentTransformation = item as ArgumentTransformationAttribute;123            if (argumentTransformation != null)124            {125                // Get an EngineIntrinsics instance using the context of the thread.126 127                ExecutionContext context = Runspaces.LocalPipeline.GetExecutionContextFromTLS();128                EngineIntrinsics engine = null;129 130                if (context != null)131                {132                    engine = context.EngineIntrinsics;133                }134 135                variableValue = argumentTransformation.TransformInternal(engine, variableValue);136            }137 138            if (!PSVariable.IsValidValue(variableValue, item))139            {140                ValidationMetadataException e = new ValidationMetadataException(141                    "ValidateSetFailure",142                    null,143                    Metadata.InvalidMetadataForCurrentValue,144                    _variable.Name,145                    ((_variable.Value != null) ? _variable.Value.ToString() : string.Empty));146 147                throw e;148            }149 150            return variableValue;151        }152 153        /// <summary>154        /// The variable whose value needs to be verified anytime155        /// the attributes change.156        /// </summary>157        private readonly PSVariable _variable;158        #endregion private data159    }160}161