Refactor command line parsing to enable extensions there in light.exe

Fixes wixtoolset/issues#5845

1 files changed, 211 insertions, 0 deletions

diff --git a/src/WixToolset.Core/CommandLine/CommandLineArguments.cs b/src/WixToolset.Core/CommandLine/CommandLineArguments.cs
new file mode 100644
index 00000000..37adcfd3
--- /dev/null
+++ b/src/WixToolset.Core/CommandLine/CommandLineArguments.cs
@@ -0,0 +1,211 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+namespace WixToolset.Core.CommandLine
+{
+    using System;
+    using System.Collections.Generic;
+    using System.IO;
+    using System.Text;
+    using System.Text.RegularExpressions;
+    using WixToolset.Extensibility.Services;
+
+    internal class CommandLineArguments : ICommandLineArguments
+    {
+        public string[] OriginalArguments { get; set; }
+
+        public string[] Arguments { get; set; }
+
+        public string[] Extensions { get; set; }
+
+        public string ErrorArgument { get; set; }
+
+        private IServiceProvider ServiceProvider { get; }
+
+        public CommandLineArguments(IServiceProvider serviceProvider)
+        {
+            this.ServiceProvider = serviceProvider;
+        }
+
+        public void Populate(string commandLine)
+        {
+            var args = CommandLineArguments.ParseArgumentsToArray(commandLine);
+
+            this.Populate(args.ToArray());
+        }
+
+        public void Populate(string[] args)
+        {
+            this.FlattenArgumentsWithResponseFilesIntoOriginalArguments(args);
+
+            this.ProcessArgumentsAndParseExtensions(this.OriginalArguments);
+        }
+
+        public IParseCommandLine Parse()
+        {
+            var messaging = (IMessaging)this.ServiceProvider.GetService(typeof(IMessaging));
+
+            return new ParseCommandLine(messaging, this.Arguments, this.ErrorArgument);
+        }
+
+        private void FlattenArgumentsWithResponseFilesIntoOriginalArguments(string[] commandLineArguments)
+        {
+            List<string> args = new List<string>();
+
+            foreach (var arg in commandLineArguments)
+            {
+                if ('@' == arg[0])
+                {
+                    var responseFileArguments = CommandLineArguments.ParseResponseFile(arg.Substring(1));
+                    args.AddRange(responseFileArguments);
+                }
+                else
+                {
+                    args.Add(arg);
+                }
+            }
+
+            this.OriginalArguments = args.ToArray();
+        }
+
+        private void ProcessArgumentsAndParseExtensions(string[] args)
+        {
+            var arguments = new List<string>();
+            var extensions = new List<string>();
+
+            for (var i = 0; i < args.Length; ++i)
+            {
+                var arg = args[i];
+
+                if ("-ext" == arg || "/ext" == arg)
+                {
+                    if (!CommandLineArguments.IsSwitchAt(args, ++i))
+                    {
+                        extensions.Add(args[i]);
+                    }
+                    else
+                    {
+                        this.ErrorArgument = arg;
+                        break;
+                    }
+                }
+                else
+                {
+                    arguments.Add(arg);
+                }
+            }
+
+            this.Arguments = arguments.ToArray();
+            this.Extensions = extensions.ToArray();
+        }
+
+        private static List<string> ParseResponseFile(string responseFile)
+        {
+            string arguments;
+
+            using (StreamReader reader = new StreamReader(responseFile))
+            {
+                arguments = reader.ReadToEnd();
+            }
+
+            return CommandLineArguments.ParseArgumentsToArray(arguments);
+        }
+
+        private static List<string> ParseArgumentsToArray(string arguments)
+        {
+            // Scan and parse the arguments string, dividing up the arguments based on whitespace.
+            // Unescaped quotes cause whitespace to be ignored, while the quotes themselves are removed.
+            // Quotes may begin and end inside arguments; they don't necessarily just surround whole arguments.
+            // Escaped quotes and escaped backslashes also need to be unescaped by this process.
+
+            // Collects the final list of arguments to be returned.
+            var argsList = new List<string>();
+
+            // True if we are inside an unescaped quote, meaning whitespace should be ignored.
+            var insideQuote = false;
+
+            // Index of the start of the current argument substring; either the start of the argument
+            // or the start of a quoted or unquoted sequence within it.
+            var partStart = 0;
+
+            // The current argument string being built; when completed it will be added to the list.
+            var arg = new StringBuilder();
+
+            for (int i = 0; i <= arguments.Length; i++)
+            {
+                if (i == arguments.Length || (Char.IsWhiteSpace(arguments[i]) && !insideQuote))
+                {
+                    // Reached a whitespace separator or the end of the string.
+
+                    // Finish building the current argument.
+                    arg.Append(arguments.Substring(partStart, i - partStart));
+
+                    // Skip over the whitespace character.
+                    partStart = i + 1;
+
+                    // Add the argument to the list if it's not empty.
+                    if (arg.Length > 0)
+                    {
+                        argsList.Add(CommandLineArguments.ExpandEnvironmentVariables(arg.ToString()));
+                        arg.Length = 0;
+                    }
+                }
+                else if (i > partStart && arguments[i - 1] == '\\')
+                {
+                    // Check the character following an unprocessed backslash.
+                    // Unescape quotes, and backslashes followed by a quote.
+                    if (arguments[i] == '"' || (arguments[i] == '\\' && arguments.Length > i + 1 && arguments[i + 1] == '"'))
+                    {
+                        // Unescape the quote or backslash by skipping the preceeding backslash.
+                        arg.Append(arguments.Substring(partStart, i - 1 - partStart));
+                        arg.Append(arguments[i]);
+                        partStart = i + 1;
+                    }
+                }
+                else if (arguments[i] == '"')
+                {
+                    // Add the quoted or unquoted section to the argument string.
+                    arg.Append(arguments.Substring(partStart, i - partStart));
+
+                    // And skip over the quote character.
+                    partStart = i + 1;
+
+                    insideQuote = !insideQuote;
+                }
+            }
+
+            return argsList;
+        }
+
+        private static string ExpandEnvironmentVariables(string arguments)
+        {
+            var id = Environment.GetEnvironmentVariables();
+
+            var regex = new Regex("(?<=\\%)(?:[\\w\\.]+)(?=\\%)");
+            MatchCollection matches = regex.Matches(arguments);
+
+            string value = String.Empty;
+            for (int i = 0; i <= (matches.Count - 1); i++)
+            {
+                try
+                {
+                    var key = matches[i].Value;
+                    regex = new Regex(String.Concat("(?i)(?:\\%)(?:", key, ")(?:\\%)"));
+                    value = id[key].ToString();
+                    arguments = regex.Replace(arguments, value);
+                }
+                catch (NullReferenceException)
+                {
+                    // Collapse unresolved environment variables.
+                    arguments = regex.Replace(arguments, value);
+                }
+            }
+
+            return arguments;
+        }
+
+        private static bool IsSwitchAt(string[] args, int index)
+        {
+            return args.Length > index && !String.IsNullOrEmpty(args[index]) && ('/' == args[index][0] || '-' == args[index][0]);
+        }
+    }
+}