MegaBites-AI/Windows-powershell

1// Copyright (c) Microsoft Corporation.2// Licensed under the MIT License.3 4using System.Collections;5using System.Management.Automation.Internal;6using System.Management.Automation.Language;7using System.Runtime.CompilerServices;8 9namespace System.Management.Automation10{11    /// <summary>12    /// The parameter binder for shell functions.13    /// </summary>14    internal class ScriptParameterBinder : ParameterBinderBase15    {16        #region ctor17 18        /// <summary>19        /// Constructs a ScriptParameterBinder with the specified context.20        /// </summary>21        /// <param name="script">22        /// The script block representing the code being run23        /// </param>24        /// <param name="invocationInfo">25        /// The invocation information about the code that is being run.26        /// </param>27        /// <param name="context">28        /// The context under which the shell function is executing.29        /// </param>30        /// <param name="command">31        /// The command instance that represents the script in a pipeline. May be null.32        /// </param>33        /// <param name="localScope">34        /// If binding in a new local scope, the scope to set variables in.  If dotting, the value is null.35        /// </param>36        internal ScriptParameterBinder(37            ScriptBlock script,38            InvocationInfo invocationInfo,39            ExecutionContext context,40            InternalCommand command,41            SessionStateScope localScope) : base(invocationInfo, context, command)42        {43            Diagnostics.Assert(script != null, "caller to verify script is not null.");44 45            this.Script = script;46            this.LocalScope = localScope;47        }48 49        private readonly CallSite<Func<CallSite, object, object>> _copyMutableValueSite =50            CallSite<Func<CallSite, object, object>>.Create(PSVariableAssignmentBinder.Get());51 52        internal object CopyMutableValues(object o)53        {54            // The variable assignment binder copies mutable values and returns other values as is.55            return _copyMutableValueSite.Target.Invoke(_copyMutableValueSite, o);56        }57 58        #endregion ctor59 60        #region internal members61 62        #region Parameter default values63 64        /// <summary>65        /// Gets the default value for the specified parameter.66        /// </summary>67        /// <param name="name">68        /// The name of the parameter to get the default value of.69        /// </param>70        /// <returns>71        /// The default value of the specified parameter.72        /// </returns>73        /// <exception cref="Exception">See SessionStateInternal.GetVariableValue.</exception>74        internal override object GetDefaultParameterValue(string name)75        {76            RuntimeDefinedParameter runtimeDefinedParameter;77            if (Script.RuntimeDefinedParameters.TryGetValue(name, out runtimeDefinedParameter))78            {79                return GetDefaultScriptParameterValue(runtimeDefinedParameter);80            }81 82            return null;83        }84 85        #endregion Parameter default values86 87        #region Parameter binding88 89        /// <summary>90        /// Binds the parameters to local variables in the function scope.91        /// </summary>92        /// <param name="name">93        ///     The name of the parameter to bind the value to.94        /// </param>95        /// <param name="value">96        ///     The value to bind to the parameter. It should be assumed by97        ///     derived classes that the proper type coercion has already taken98        ///     place and that any prerequisite metadata has been satisfied.99        /// </param>100        /// <param name="parameterMetadata"></param>101        internal override void BindParameter(string name, object value, CompiledCommandParameter parameterMetadata)102        {103            if (value == AutomationNull.Value || value == UnboundParameter.Value)104            {105                value = null;106            }107 108            Diagnostics.Assert(name != null, "The caller should verify that name is not null");109 110            var varPath = new VariablePath(name, VariablePathFlags.Variable);111 112            // If the parameter was allocated in the LocalsTuple, we can avoid creating a PSVariable,113            if (LocalScope != null114                && varPath.IsAnyLocal()115                && LocalScope.TrySetLocalParameterValue(varPath.UnqualifiedPath, CopyMutableValues(value)))116            {117                return;118            }119 120            // Otherwise we'll fall through and enter a new PSVariable in the current scope.  This121            // is what normally happens when dotting (though the above may succeed if a parameter name122            // was an automatic variable like $PSBoundParameters.123 124            // First we need to make a variable instance and apply125            // any attributes from the script.126 127            PSVariable variable = new PSVariable(varPath.UnqualifiedPath, value,128                                                 varPath.IsPrivate ? ScopedItemOptions.Private : ScopedItemOptions.None);129            Context.EngineSessionState.SetVariable(varPath, variable, false, CommandOrigin.Internal);130            RuntimeDefinedParameter runtimeDefinedParameter;131            if (Script.RuntimeDefinedParameters.TryGetValue(name, out runtimeDefinedParameter))132            {133                // The attributes have already been checked and conversions run, so it is wrong134                // to do so again.135                variable.AddParameterAttributesNoChecks(runtimeDefinedParameter.Attributes);136            }137        }138 139        /// <summary>140        /// Return the default value of a script parameter, evaluating the parse tree if necessary.141        /// </summary>142        internal object GetDefaultScriptParameterValue(RuntimeDefinedParameter parameter, IDictionary implicitUsingParameters = null)143        {144            object result = parameter.Value;145 146            var compiledDefault = result as Compiler.DefaultValueExpressionWrapper;147            if (compiledDefault != null)148            {149                result = compiledDefault.GetValue(Context, Script.SessionStateInternal, implicitUsingParameters);150            }151 152            return result;153        }154 155        #endregion Parameter binding156 157        #endregion internal members158 159        #region private members160 161        /// <summary>162        /// The script that is being bound to.163        /// </summary>164        internal ScriptBlock Script { get; }165 166        internal SessionStateScope LocalScope { get; set; }167 168        #endregion private members169    }170}171