CompiledScriptBlock.cs

// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.

using System.Collections;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Management.Automation.Configuration;
using System.Management.Automation.Internal;
using System.Management.Automation.Language;
using System.Management.Automation.Runspaces;
using System.Management.Automation.Tracing;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Runtime.Serialization;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using System.Threading.Tasks;
#if LEGACYTELEMETRY
using Microsoft.PowerShell.Telemetry.Internal;
#endif

namespace System.Management.Automation
{
    internal enum CompileInterpretChoice
    {
        NeverCompile,
        AlwaysCompile,
        CompileOnDemand
    }

    internal enum ScriptBlockClauseToInvoke
    {
        Begin,
        Process,
        End,
        ProcessBlockOnly,
    }

    internal class CompiledScriptBlockData
    {
        internal CompiledScriptBlockData(IParameterMetadataProvider ast, bool isFilter)
        {
            _ast = ast;
            this.IsFilter = isFilter;
            this.Id = Guid.NewGuid();
        }

        internal CompiledScriptBlockData(string scriptText, bool isProductCode)
        {
            _isProductCode = isProductCode;
            _scriptText = scriptText;
            this.Id = Guid.NewGuid();
        }

        internal bool Compile(bool optimized)
        {
            if (_attributes == null)
            {
                InitializeMetadata();
            }

            // We need the name to index map to check if any allscope variables are assigned.  If they
            // are, we can't run the optimized version, so we'll compile once more unoptimized and run that.
            if (optimized && NameToIndexMap == null)
            {
                CompileOptimized();
            }

            optimized = optimized && !VariableAnalysis.AnyVariablesCouldBeAllScope(NameToIndexMap);

            if (!optimized && !_compiledUnoptimized)
            {
                CompileUnoptimized();
            }
            else if (optimized && !_compiledOptimized)
            {
                CompileOptimized();
            }

            return optimized;
        }

        private void InitializeMetadata()
        {
            lock (this)
            {
                if (_attributes != null)
                {
                    // Another thread must have initialized the metadata.
                    return;
                }

                Attribute[] attributes;
                CmdletBindingAttribute cmdletBindingAttribute = null;
                if (!Ast.HasAnyScriptBlockAttributes())
                {
                    attributes = Array.Empty<Attribute>();
                }
                else
                {
                    attributes = Ast.GetScriptBlockAttributes().ToArray();
                    foreach (var attribute in attributes)
                    {
                        if (attribute is CmdletBindingAttribute c)
                        {
                            cmdletBindingAttribute ??= c;
                        }
                        else if (attribute is DebuggerHiddenAttribute)
                        {
                            DebuggerHidden = true;
                        }
                        else if (attribute is DebuggerStepThroughAttribute || attribute is DebuggerNonUserCodeAttribute)
                        {
                            DebuggerStepThrough = true;
                        }
                    }

                    _usesCmdletBinding = cmdletBindingAttribute != null;
                }

                bool automaticPosition = cmdletBindingAttribute == null || cmdletBindingAttribute.PositionalBinding;
                var runtimeDefinedParameterDictionary =
                    Ast.GetParameterMetadata(automaticPosition, ref _usesCmdletBinding);

                // Initialize these fields last - if there were any exceptions, we don't want the partial results cached.
                _attributes = attributes;
                _runtimeDefinedParameterDictionary = runtimeDefinedParameterDictionary;
            }
        }

        private void CompileUnoptimized()
        {
            lock (this)
            {
                if (_compiledUnoptimized)
                {
                    // Another thread must have compiled while we were waiting on the lock.
                    return;
                }

                ReallyCompile(false);
                _compiledUnoptimized = true;
            }
        }

        private void CompileOptimized()
        {
            lock (this)
            {
                if (_compiledOptimized)
                {
                    // Another thread must have compiled while we were waiting on the lock.
                    return;
                }

                ReallyCompile(true);
                _compiledOptimized = true;
            }
        }

        private void ReallyCompile(bool optimize)
        {
#if LEGACYTELEMETRY
            var sw = new Stopwatch();
            sw.Start();
#endif
            bool etwEnabled = ParserEventSource.Log.IsEnabled();
            if (etwEnabled)
            {
                var extent = _ast.Body.Extent;
                var text = extent.Text;
                ParserEventSource.Log.CompileStart(
                    FileName: ParserEventSource.GetFileOrScript(extent.File, text),
                    text.Length,
                    optimize);
            }

            PerformSecurityChecks();

            Compiler compiler = new Compiler();
            compiler.Compile(this, optimize);

#if LEGACYTELEMETRY
            if (!IsProductCode)
            {
                TelemetryAPI.ReportScriptTelemetry((Ast)_ast, !optimize, sw.ElapsedMilliseconds);
            }
#endif
            if (etwEnabled) ParserEventSource.Log.CompileStop();
        }

        private void PerformSecurityChecks()
        {
            if (!(Ast is ScriptBlockAst scriptBlockAst))
            {
                // Checks are only needed at the top level.
                return;
            }

            var scriptExtent = scriptBlockAst.Extent;
            var scriptFile = scriptExtent.File;

            if (scriptFile != null
                && scriptFile.EndsWith(StringLiterals.PowerShellDataFileExtension, StringComparison.OrdinalIgnoreCase)
                && IsScriptBlockInFactASafeHashtable())
            {
                // Skip the scan for .psd1 files if their content is in fact a safe HashtableAst.
                return;
            }

            // Call the AMSI API to determine if the script block has malicious content
            var amsiResult = AmsiUtils.ScanContent(scriptExtent.Text, scriptFile);

            if (amsiResult == AmsiUtils.AmsiNativeMethods.AMSI_RESULT.AMSI_RESULT_DETECTED)
            {
                var parseError = new ParseError(
                    scriptExtent,
                    "ScriptContainedMaliciousContent",
                    ParserStrings.ScriptContainedMaliciousContent);
                throw new ParseException(new[] { parseError });
            }
            else if (amsiResult >= AmsiUtils.AmsiNativeMethods.AMSI_RESULT.AMSI_RESULT_BLOCKED_BY_ADMIN_BEGIN
                && amsiResult <= AmsiUtils.AmsiNativeMethods.AMSI_RESULT.AMSI_RESULT_BLOCKED_BY_ADMIN_END)
            {
                // Certain policies set by an administrator blocked this content on this machine
                var parseError = new ParseError(
                    scriptExtent,
                    "ScriptHasAdminBlockedContent",
                    StringUtil.Format(ParserStrings.ScriptHasAdminBlockedContent, amsiResult));
                throw new ParseException(new[] { parseError });
            }

            if (ScriptBlock.CheckSuspiciousContent(scriptBlockAst) != null)
            {
                HasSuspiciousContent = true;
            }

            // A local function to check if the ScriptBlockAst is in fact a safe HashtableAst.
            bool IsScriptBlockInFactASafeHashtable()
            {
                // NOTE: The code below depends on the current member structure of 'ScriptBlockAst'
                // to determine if the ScriptBlockAst is in fact just a HashtableAst. If AST types
                // are enhanced, such as new members added to 'ScriptBlockAst', the code here needs
                // to be reviewed and changed accordingly.

                if (scriptBlockAst.BeginBlock != null
                    || scriptBlockAst.ProcessBlock != null
                    || scriptBlockAst.ParamBlock != null
                    || scriptBlockAst.DynamicParamBlock != null
                    || scriptBlockAst.ScriptRequirements != null
                    || scriptBlockAst.UsingStatements.Count > 0
                    || scriptBlockAst.Attributes.Count > 0)
                {
                    return false;
                }

                NamedBlockAst endBlock = scriptBlockAst.EndBlock;
                if (!endBlock.Unnamed || endBlock.Traps != null || endBlock.Statements.Count != 1)
                {
                    return false;
                }

                if (!(endBlock.Statements[0] is PipelineAst pipelineAst))
                {
                    return false;
                }

                if (!(pipelineAst.GetPureExpression() is HashtableAst hashtableAst))
                {
                    return false;
                }

                // After the above steps, we know the ScriptBlockAst is in fact just a HashtableAst,
                // now we need to check if the HashtableAst is safe.
                return IsSafeValueVisitor.Default.IsAstSafe(hashtableAst);
            }
        }

        // We delay parsing scripts loaded on startup, so we save the text.
        private string _scriptText;

        internal IParameterMetadataProvider Ast { get => _ast ?? DelayParseScriptText(); }

        private IParameterMetadataProvider _ast;

        private IParameterMetadataProvider DelayParseScriptText()
        {
            lock (this)
            {
                if (_ast != null)
                {
                    return _ast;
                }

                ParseError[] errors;
                _ast = (new Parser()).Parse(null, _scriptText, null, out errors, ParseMode.Default);
                if (errors.Length != 0)
                {
                    throw new ParseException(errors);
                }

                _scriptText = null;
                return _ast;
            }
        }

        internal Type LocalsMutableTupleType { get; set; }

        internal Type UnoptimizedLocalsMutableTupleType { get; set; }

        internal Func<MutableTuple> LocalsMutableTupleCreator { get; set; }

        internal Func<MutableTuple> UnoptimizedLocalsMutableTupleCreator { get; set; }

        internal Dictionary<string, int> NameToIndexMap { get; set; }

        internal Action<FunctionContext> DynamicParamBlock { get; set; }

        internal Action<FunctionContext> UnoptimizedDynamicParamBlock { get; set; }

        internal Action<FunctionContext> BeginBlock { get; set; }

        internal Action<FunctionContext> UnoptimizedBeginBlock { get; set; }

        internal Action<FunctionContext> ProcessBlock { get; set; }

        internal Action<FunctionContext> UnoptimizedProcessBlock { get; set; }

        internal Action<FunctionContext> EndBlock { get; set; }

        internal Action<FunctionContext> UnoptimizedEndBlock { get; set; }

        internal IScriptExtent[] SequencePoints { get; set; }

        private RuntimeDefinedParameterDictionary _runtimeDefinedParameterDictionary;
        private Attribute[] _attributes;
        private bool _usesCmdletBinding;
        private bool _compiledOptimized;
        private bool _compiledUnoptimized;
        private bool _hasSuspiciousContent;
        private bool? _isProductCode;

        internal bool DebuggerHidden { get; set; }

        internal bool DebuggerStepThrough { get; set; }

        internal Guid Id { get; private set; }

        internal bool HasLogged { get; set; }

        internal bool SkipLogging { get; set; }

        internal bool IsFilter { get; }

        internal bool IsProductCode
        {
            get
            {
                if (_isProductCode == null)
                {
                    _isProductCode = SecuritySupport.IsProductBinary(((Ast)_ast).Extent.File);
                }

                return _isProductCode.Value;
            }
        }

        internal bool GetIsConfiguration()
        {
            // Use _ast instead of Ast
            //  If we access Ast, we may parse a "delay parsed" script block unnecessarily
            //  if _ast is null - it can't be a configuration as there is no way to create a configuration that way
            var scriptBlockAst = _ast as ScriptBlockAst;
            return scriptBlockAst != null && scriptBlockAst.IsConfiguration;
        }

        internal bool HasSuspiciousContent
        {
            get
            {
                Diagnostics.Assert(
                    _compiledOptimized || _compiledUnoptimized,
                    "HasSuspiciousContent is not set correctly before being compiled");
                return _hasSuspiciousContent;
            }

            set => _hasSuspiciousContent = value;
        }

        private MergedCommandParameterMetadata _parameterMetadata;

        internal List<Attribute> GetAttributes()
        {
            if (_attributes == null)
            {
                InitializeMetadata();
            }

            Diagnostics.Assert(
                _attributes != null,
                "after initialization, attributes is never null, must be an empty list if no attributes.");
            return _attributes.ToList();
        }

        internal bool UsesCmdletBinding
        {
            get
            {
                if (_attributes != null)
                {
                    return _usesCmdletBinding;
                }

                return Ast.UsesCmdletBinding();
            }
        }

        internal RuntimeDefinedParameterDictionary RuntimeDefinedParameters
        {
            get
            {
                if (_runtimeDefinedParameterDictionary == null)
                {
                    InitializeMetadata();
                }

                return _runtimeDefinedParameterDictionary;
            }
        }

        internal CmdletBindingAttribute CmdletBindingAttribute
        {
            get
            {
                if (_runtimeDefinedParameterDictionary == null)
                {
                    InitializeMetadata();
                }

                return _usesCmdletBinding
                    ? (CmdletBindingAttribute)Array.Find(_attributes, static attr => attr is CmdletBindingAttribute)
                    : null;
            }
        }

        internal ObsoleteAttribute ObsoleteAttribute
        {
            get
            {
                if (_runtimeDefinedParameterDictionary == null)
                {
                    InitializeMetadata();
                }

                return (ObsoleteAttribute)Array.Find(_attributes, static attr => attr is ObsoleteAttribute);
            }
        }

        internal ExperimentalAttribute ExperimentalAttribute
        {
            get
            {
                if (_expAttribute == ExperimentalAttribute.None)
                {
                    lock (this)
                    {
                        if (_expAttribute == ExperimentalAttribute.None)
                        {
                            _expAttribute = Ast.GetExperimentalAttributes().FirstOrDefault();
                        }
                    }
                }

                return _expAttribute;
            }
        }

        private ExperimentalAttribute _expAttribute = ExperimentalAttribute.None;

        public MergedCommandParameterMetadata GetParameterMetadata(ScriptBlock scriptBlock)
        {
            if (_parameterMetadata == null)
            {
                lock (this)
                {
                    if (_parameterMetadata == null)
                    {
                        CommandMetadata metadata = new CommandMetadata(
                            scriptBlock,
                            string.Empty,
                            LocalPipeline.GetExecutionContextFromTLS());
                        _parameterMetadata = metadata.StaticCommandParameterMetadata;
                    }
                }
            }

            return _parameterMetadata;
        }

        public override string ToString()
        {
            if (_scriptText != null)
            {
                return _scriptText;
            }

            if (_ast is ScriptBlockAst sbAst)
            {
                return sbAst.ToStringForSerialization();
            }

            var generatedMemberFunctionAst = _ast as CompilerGeneratedMemberFunctionAst;
            if (generatedMemberFunctionAst != null)
            {
                return generatedMemberFunctionAst.Extent.Text;
            }

            var funcDefn = (FunctionDefinitionAst)_ast;
            if (funcDefn.Parameters == null)
            {
                return funcDefn.Body.ToStringForSerialization();
            }

            var sb = new StringBuilder();
            sb.Append(funcDefn.GetParamTextFromParameterList());
            sb.Append(funcDefn.Body.ToStringForSerialization());
            return sb.ToString();
        }
    }

    [Serializable]
    public partial class ScriptBlock : ISerializable
    {
        private readonly CompiledScriptBlockData _scriptBlockData;

        internal ScriptBlock(IParameterMetadataProvider ast, bool isFilter)
            : this(new CompiledScriptBlockData(ast, isFilter))
        {
        }

        private ScriptBlock(CompiledScriptBlockData scriptBlockData)
        {
            _scriptBlockData = scriptBlockData;

            // LanguageMode is a nullable PSLanguageMode enumeration because script blocks
            // need to inherit the language mode from the context in which they are executing.
            // We can't assume FullLanguage by default when there is no context, as there are
            // script blocks (such as the script blocks used in Workflow activities) that are
            // created by the host without a "current language mode" to inherit. They ultimately
            // get their language mode set when they are finally invoked in a constrained
            // language runspace.
            // Script blocks that should always be run under FullLanguage mode (i.e.: set in
            // InitialSessionState, etc.) should explicitly set the LanguageMode to FullLanguage
            // when they are created.
            ExecutionContext context = LocalPipeline.GetExecutionContextFromTLS();
            if (context != null)
            {
                this.LanguageMode = context.LanguageMode;
            }
        }

        /// <summary>
        /// Protected constructor to support ISerializable.
        /// </summary>
        protected ScriptBlock(SerializationInfo info, StreamingContext context)
        {
        }

        private static readonly ConcurrentDictionary<Tuple<string, string>, ScriptBlock> s_cachedScripts =
            new ConcurrentDictionary<Tuple<string, string>, ScriptBlock>();

        internal static ScriptBlock TryGetCachedScriptBlock(string fileName, string fileContents)
        {
            if (InternalTestHooks.IgnoreScriptBlockCache)
            {
                return null;
            }

            ScriptBlock scriptBlock;
            var key = Tuple.Create(fileName, fileContents);
            if (s_cachedScripts.TryGetValue(key, out scriptBlock))
            {
                Diagnostics.Assert(
                    scriptBlock.SessionStateInternal == null,
                    "A cached scriptblock should not have it's session state bound, that causes a memory leak.");
                return scriptBlock.Clone();
            }

            return null;
        }

        private static bool IsDynamicKeyword(Ast ast)
            => ast is CommandAst cmdAst && cmdAst.DefiningKeyword != null;

        private static bool IsUsingTypes(Ast ast)
            => ast is UsingStatementAst cmdAst && cmdAst.IsUsingModuleOrAssembly();

        internal static void CacheScriptBlock(ScriptBlock scriptBlock, string fileName, string fileContents)
        {
            if (InternalTestHooks.IgnoreScriptBlockCache)
            {
                return;
            }

            // Don't cache scriptblocks that have
            // a) dynamic keywords
            // b) 'using module' or 'using assembly'
            // The definition of the dynamic keyword could change, consequently changing how the source text should be parsed.
            // Exported types definitions from 'using module' could change, we need to do all parse-time checks again.
            // TODO(sevoroby): we can optimize it to ignore 'using' if there are no actual type usage in locally defined types.

            // using is always a top-level statements in scriptBlock, we don't need to search in child blocks.
            if (scriptBlock.Ast.Find(static ast => IsUsingTypes(ast), false) != null
                || scriptBlock.Ast.Find(static ast => IsDynamicKeyword(ast), true) != null)
            {
                return;
            }

            if (s_cachedScripts.Count > 1024)
            {
                s_cachedScripts.Clear();
            }

            var key = Tuple.Create(fileName, fileContents);
            s_cachedScripts.TryAdd(key, scriptBlock);
        }

        /// <summary>
        /// Clears the cached scriptblocks.
        /// </summary>
        internal static void ClearScriptBlockCache()
        {
            s_cachedScripts.Clear();
        }

        internal static readonly ScriptBlock EmptyScriptBlock =
            ScriptBlock.CreateDelayParsedScriptBlock(string.Empty, isProductCode: true);

        internal static ScriptBlock Create(Parser parser, string fileName, string fileContents)
        {
            var scriptBlock = TryGetCachedScriptBlock(fileName, fileContents);
            if (scriptBlock != null)
            {
                return scriptBlock;
            }

            var ast = parser.Parse(fileName, fileContents, null, out ParseError[] errors, ParseMode.Default);
            if (errors.Length != 0)
            {
                throw new ParseException(errors);
            }

            var result = new ScriptBlock(ast, isFilter: false);
            CacheScriptBlock(result, fileName, fileContents);

            // The value returned will potentially be bound to a session state.  We don't want
            // the cached script block to end up being bound to any session state, so clone
            // the return value to ensure the cached value has no session state.
            return result.Clone();
        }

        internal ScriptBlock Clone() => new ScriptBlock(_scriptBlockData);

        /// <summary>
        /// Returns the text of the script block.  The return value might not match the original text exactly.
        /// </summary>
        public override string ToString() => _scriptBlockData.ToString();

        /// <summary>
        /// Returns the text of the script block with the handling of $using expressions.
        /// </summary>
        internal string ToStringWithDollarUsingHandling(
            Tuple<List<VariableExpressionAst>, string> usingVariablesTuple)
        {
            FunctionDefinitionAst funcDefn = null;
            var sbAst = Ast as ScriptBlockAst;
            if (sbAst == null)
            {
                funcDefn = (FunctionDefinitionAst)Ast;
                sbAst = funcDefn.Body;
            }

            string sbText = sbAst.ToStringForSerialization(usingVariablesTuple, sbAst.Extent.StartOffset, sbAst.Extent.EndOffset);
            if (sbAst.ParamBlock != null)
            {
                return sbText;
            }

            string paramText;
            string additionalNewParams = usingVariablesTuple.Item2;
            if (funcDefn == null || funcDefn.Parameters == null)
            {
                paramText = "param(" + additionalNewParams + ")" + Environment.NewLine;
            }
            else
            {
                paramText = funcDefn.GetParamTextFromParameterList(usingVariablesTuple);
            }

            sbText = paramText + sbText;
            return sbText;
        }

        /// <summary>
        /// Support for <see cref="ISerializable"/>.
        /// </summary>
        public virtual void GetObjectData(SerializationInfo info, StreamingContext context)
        {
            if (info == null)
            {
                throw PSTraceSource.NewArgumentNullException(nameof(info));
            }

            string serializedContent = this.ToString();
            info.AddValue("ScriptText", serializedContent);
            info.SetType(typeof(ScriptBlockSerializationHelper));
        }

        internal PowerShell GetPowerShellImpl(
            ExecutionContext context,
            Dictionary<string, object> variables,
            bool isTrustedInput,
            bool filterNonUsingVariables,
            bool? createLocalScope,
            params object[] args)
        {
            return AstInternal.GetPowerShell(
                context,
                variables,
                isTrustedInput,
                filterNonUsingVariables,
                createLocalScope,
                args);
        }

        internal SteppablePipeline GetSteppablePipelineImpl(CommandOrigin commandOrigin, object[] args)
        {
            var pipelineAst = GetSimplePipeline(
                resourceString => throw PSTraceSource.NewInvalidOperationException(resourceString));
            Diagnostics.Assert(pipelineAst != null, "This should be checked by GetSimplePipeline");

            if (pipelineAst.PipelineElements[0] is not CommandAst)
            {
                throw PSTraceSource.NewInvalidOperationException(AutomationExceptions.CantConvertEmptyPipeline);
            }

            return PipelineOps.GetSteppablePipeline(pipelineAst, commandOrigin, this, args);
        }

        private PipelineAst GetSimplePipeline(Func<string, PipelineAst> errorHandler)
        {
            errorHandler ??= (static _ => null);

            if (HasBeginBlock || HasProcessBlock)
            {
                return errorHandler(AutomationExceptions.CanConvertOneClauseOnly);
            }

            var ast = AstInternal;
            var statements = ast.Body.EndBlock.Statements;
            if (statements.Count == 0)
            {
                return errorHandler(AutomationExceptions.CantConvertEmptyPipeline);
            }

            if (statements.Count > 1)
            {
                return errorHandler(AutomationExceptions.CanOnlyConvertOnePipeline);
            }

            if (ast.Body.EndBlock.Traps != null && ast.Body.EndBlock.Traps.Count > 0)
            {
                return errorHandler(AutomationExceptions.CantConvertScriptBlockWithTrap);
            }

            if (!(statements[0] is PipelineAst pipeAst))
            {
                return errorHandler(AutomationExceptions.CanOnlyConvertOnePipeline);
            }

            // The old code checked for empty pipeline.
            // That can't happen in the new parser (validated in the constructors),
            // so the resource CantConvertEmptyPipeline is probably unused.

            return pipeAst;
        }

        internal List<Attribute> GetAttributes() => _scriptBlockData.GetAttributes();

        internal string GetFileName() => AstInternal.Body.Extent.File;

        // GetAttributes() is asserted never return null
        internal bool IsMetaConfiguration() => GetAttributes().OfType<DscLocalConfigurationManagerAttribute>().Any();

        internal PSToken GetStartPosition() => new PSToken(Ast.Extent);

        internal MergedCommandParameterMetadata ParameterMetadata
        {
            get => _scriptBlockData.GetParameterMetadata(this);
        }

        internal bool UsesCmdletBinding { get => _scriptBlockData.UsesCmdletBinding; }

        internal bool HasDynamicParameters { get => AstInternal.Body.DynamicParamBlock != null; }

        /// <summary>
        /// DebuggerHidden.
        /// </summary>
        public bool DebuggerHidden
        {
            get => _scriptBlockData.DebuggerHidden;
            set => _scriptBlockData.DebuggerHidden = value;
        }

        /// <summary>
        /// The unique ID of this script block.
        /// </summary>
        public Guid Id { get => _scriptBlockData.Id; }

        internal bool DebuggerStepThrough
        {
            get { return _scriptBlockData.DebuggerStepThrough; }

            set { _scriptBlockData.DebuggerStepThrough = value; }
        }

        internal RuntimeDefinedParameterDictionary RuntimeDefinedParameters
        {
            get => _scriptBlockData.RuntimeDefinedParameters;
        }

        internal bool HasLogged
        {
            get => _scriptBlockData.HasLogged;
            set => _scriptBlockData.HasLogged = value;
        }

        internal bool SkipLogging
        {
            get { return _scriptBlockData.SkipLogging; }

            set { _scriptBlockData.SkipLogging = value; }
        }

        internal Assembly AssemblyDefiningPSTypes { get; set; }

        internal HelpInfo GetHelpInfo(
            ExecutionContext context,
            CommandInfo commandInfo,
            bool dontSearchOnRemoteComputer,
            Dictionary<Ast, Token[]> scriptBlockTokenCache,
            out string helpFile,
            out string helpUriFromDotLink)
        {
            helpUriFromDotLink = null;

            var commentTokens = HelpCommentsParser.GetHelpCommentTokens(AstInternal, scriptBlockTokenCache);
            if (commentTokens != null)
            {
                return HelpCommentsParser.CreateFromComments(
                    context,
                    commandInfo,
                    commentTokens.Item1,
                    commentTokens.Item2,
                    dontSearchOnRemoteComputer,
                    out helpFile,
                    out helpUriFromDotLink);
            }

            helpFile = null;
            return null;
        }

        /// <summary>
        /// Check the script block to see if it uses any language constructs not allowed in restricted language mode.
        /// </summary>
        /// <param name="allowedCommands">The commands that are allowed.</param>
        /// <param name="allowedVariables">
        /// The variables allowed in this scriptblock. If this is null, then the default variable set
        /// will be allowed. If it is an empty list, no variables will be allowed. If it is "*" then
        /// any variable will be allowed.
        /// </param>
        /// <param name="allowEnvironmentVariables">The environment variables that are allowed.</param>
        public void CheckRestrictedLanguage(
            IEnumerable<string> allowedCommands,
            IEnumerable<string> allowedVariables,
            bool allowEnvironmentVariables)
        {
            Parser parser = new Parser();

            var ast = AstInternal;
            if (HasBeginBlock || HasProcessBlock || ast.Body.ParamBlock != null)
            {
                Ast errorAst = ast.Body.BeginBlock ?? (Ast)ast.Body.ProcessBlock ?? ast.Body.ParamBlock;
                parser.ReportError(
                    errorAst.Extent,
                    nameof(ParserStrings.InvalidScriptBlockInDataSection),
                    ParserStrings.InvalidScriptBlockInDataSection);
            }

            if (HasEndBlock)
            {
                var rlc = new RestrictedLanguageChecker(
                    parser,
                    allowedCommands,
                    allowedVariables,
                    allowEnvironmentVariables);

                StatementBlockAst.InternalVisit(
                    rlc,
                    ast.Body.EndBlock.Traps,
                    ast.Body.EndBlock.Statements,
                    AstVisitAction.Continue);
            }

            if (parser.ErrorList.Count > 0)
            {
                throw new ParseException(parser.ErrorList.ToArray());
            }
        }

        internal string GetWithInputHandlingForInvokeCommand() => AstInternal.GetWithInputHandlingForInvokeCommand();

        internal string GetWithInputHandlingForInvokeCommandWithUsingExpression(
            Tuple<List<VariableExpressionAst>, string> usingVariablesTuple)
        {
            Tuple<string, string> result =
                AstInternal.GetWithInputHandlingForInvokeCommandWithUsingExpression(usingVariablesTuple);

            // result.Item1 is ParamText; result.Item2 is ScriptBlockText
            return result.Item1 == null ? result.Item2 : result.Item1 + result.Item2;
        }

        internal bool IsUsingDollarInput() => AstSearcher.IsUsingDollarInput(this.Ast);

        internal void InvokeWithPipeImpl(
            bool createLocalScope,
            Dictionary<string, ScriptBlock> functionsToDefine,
            List<PSVariable> variablesToDefine,
            ErrorHandlingBehavior errorHandlingBehavior,
            object dollarUnder,
            object input,
            object scriptThis,
            Pipe outputPipe,
            InvocationInfo invocationInfo,
            params object[] args)
        {
            InvokeWithPipeImpl(
                ScriptBlockClauseToInvoke.ProcessBlockOnly,
                createLocalScope,
                functionsToDefine,
                variablesToDefine,
                errorHandlingBehavior,
                dollarUnder,
                input,
                scriptThis,
                outputPipe,
                invocationInfo,
                args);
        }

        internal void InvokeWithPipeImpl(
            ScriptBlockClauseToInvoke clauseToInvoke,
            bool createLocalScope,
            Dictionary<string, ScriptBlock> functionsToDefine,
            List<PSVariable> variablesToDefine,
            ErrorHandlingBehavior errorHandlingBehavior,
            object dollarUnder,
            object input,
            object scriptThis,
            Pipe outputPipe,
            InvocationInfo invocationInfo,
            params object[] args)
        {
            if ((clauseToInvoke == ScriptBlockClauseToInvoke.Begin && !HasBeginBlock)
                || (clauseToInvoke == ScriptBlockClauseToInvoke.Process && !HasProcessBlock)
                || (clauseToInvoke == ScriptBlockClauseToInvoke.End && !HasEndBlock))
            {
                return;
            }

            ExecutionContext context = GetContextFromTLS();
            Diagnostics.Assert(
                SessionStateInternal == null || SessionStateInternal.ExecutionContext == context,
                "The scriptblock is being invoked in a runspace different than the one where it was created");

            if (context.CurrentPipelineStopping)
            {
                throw new PipelineStoppedException();
            }

            // Validate at the arguments are consistent. The only public API that gets you here never sets createLocalScope to false...
            Diagnostics.Assert(
                createLocalScope || functionsToDefine == null,
                "When calling ScriptBlock.InvokeWithContext(), if 'functionsToDefine' != null then 'createLocalScope' must be true");
            Diagnostics.Assert(
                createLocalScope || variablesToDefine == null,
                "When calling ScriptBlock.InvokeWithContext(), if 'variablesToDefine' != null then 'createLocalScope' must be true");