File size: 5,177 Bytes
8c763fb | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 | // Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.
using System.Management.Automation.Host;
using System.Management.Automation.Language;
using System.Management.Automation.Runspaces;
using System.Text;
namespace System.Management.Automation
{
/// <summary>
/// This class aggregates the objects necessary for the Monad
/// engine to run.
/// </summary>
internal class AutomationEngine
{
static AutomationEngine()
{
// Register the encoding provider to load encodings that are not supported by default,
// so as to allow them to be used in user's script/code.
Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
}
// Holds the parser to use for this instance of the engine...
internal Parser EngineParser;
/// <summary>
/// Returns the handle to the execution context
/// for this instance of the automation engine.
/// </summary>
internal ExecutionContext Context { get; }
/// <summary>
/// Gets the CommandDiscovery instance for the current engine.
/// </summary>
internal CommandDiscovery CommandDiscovery { get; }
/// <summary>
/// The principal constructor that most hosts will use when creating
/// an instance of the automation engine. It allows you to pass in an
/// instance of PSHost that provides the host-specific I/O routines, etc.
/// </summary>
internal AutomationEngine(PSHost hostInterface, InitialSessionState iss)
{
#if !UNIX
// Update the env variable PATHEXT to contain .CPL
var pathext = Environment.GetEnvironmentVariable("PATHEXT");
if (string.IsNullOrEmpty(pathext))
{
Environment.SetEnvironmentVariable("PATHEXT", ".CPL");
}
else if (!(pathext.EndsWith(";.CPL", StringComparison.OrdinalIgnoreCase) ||
pathext.StartsWith(".CPL;", StringComparison.OrdinalIgnoreCase) ||
pathext.Contains(";.CPL;", StringComparison.OrdinalIgnoreCase) ||
pathext.Equals(".CPL", StringComparison.OrdinalIgnoreCase)))
{
// Fast skip if we already added the extention as ";.CPL".
// Fast skip if user already added the extention.
pathext += pathext[pathext.Length - 1] == ';' ? ".CPL" : ";.CPL";
Environment.SetEnvironmentVariable("PATHEXT", pathext);
}
#endif
Context = new ExecutionContext(this, hostInterface, iss);
EngineParser = new Language.Parser();
CommandDiscovery = new CommandDiscovery(Context);
// Load the iss, resetting everything to it's defaults...
iss.Bind(Context, updateOnly: false, module: null, noClobber: false, local: false, setLocation: true);
}
/// <summary>
/// Method to take a string and expand any metachars in it.
/// </summary>
internal string Expand(string s)
{
var ast = Parser.ScanString(s);
// ExpandString is assumed to invoke code, so passing 'IsTrustedInput'
return Compiler.GetExpressionValue(ast, true, Context, Context.EngineSessionState) as string ?? string.Empty;
}
/// <summary>
/// Compile a piece of text into a parse tree for later execution.
/// </summary>
/// <param name="script">The text to parse.</param>
/// <param name="addToHistory">True if-and-only-if the scriptblock will be added to history.</param>
/// <returns>The parse text as a parsetree node.</returns>
internal ScriptBlock ParseScriptBlock(string script, bool addToHistory)
{
return ParseScriptBlock(script, null, addToHistory);
}
internal ScriptBlock ParseScriptBlock(string script, string fileName, bool addToHistory)
{
ParseError[] errors;
var ast = EngineParser.Parse(fileName, script, null, out errors, ParseMode.Default);
if (addToHistory)
{
EngineParser.SetPreviousFirstLastToken(Context);
}
if (errors.Length > 0)
{
ParseException ex = errors[0].IncompleteInput
? new IncompleteParseException(errors[0].Message, errors[0].ErrorId)
: new ParseException(errors);
if (addToHistory)
{
// Try associating the parsing error with the history item if we can.
InvocationInfo invInfo = ex.ErrorRecord.InvocationInfo;
LocalRunspace localRunspace = Context.CurrentRunspace as LocalRunspace;
if (invInfo is not null && localRunspace?.History is not null)
{
invInfo.HistoryId = localRunspace.History.GetNextHistoryId();
}
}
throw ex;
}
return new ScriptBlock(ast, isFilter: false);
}
}
}
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