zeroinstall/injector/runenv.cli.cs

   1 /*
   2  * Copyright 2006-2012 Bastian Eicher
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a copy
   5  * of this software and associated documentation files (the "Software"), to deal
   6  * in the Software without restriction, including without limitation the rights
   7  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   8  * copies of the Software, and to permit persons to whom the Software is
   9  * furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included in
  12  * all copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  17  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  18  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  19  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  20  * THE SOFTWARE.
  21  */
  22
  23 using System;
  24 using System.Collections.Generic;
  25 using System.Diagnostics;
  26 using System.IO;
  27 using System.Text;
  28
  29 /// <summary>
  30 /// This helper executable launches a command-line specified in specific environment variables.
  31 /// <summary>
  32 public class RunEnv
  33 {
  34     public static int Main(string[] args)
  35     {
  36         string envName = Path.GetFileName(System.Environment.GetCommandLineArgs()[0]);
  37         string envFile = Environment.GetEnvironmentVariable("0install-runenv-file-" + envName);
  38         string envArgs = Environment.GetEnvironmentVariable("0install-runenv-args-" + envName);
  39         string userArgs = ConcatenateEscapeArgument(args);
  40
  41         ProcessStartInfo startInfo = new ProcessStartInfo(envFile, string.IsNullOrEmpty(userArgs) ? envArgs : envArgs + " " + userArgs);
  42         startInfo.UseShellExecute = false;
  43         Process process = Process.Start(startInfo);
  44         process.WaitForExit();
  45         return process.ExitCode;
  46     }
  47
  48     #region StringUtils
  49     /// <summary>
  50     /// Escapes a string for use as a Windows command-line argument, making sure it is encapsulated within <code>"</code> if it contains whitespace characters.
  51     /// </summary>
  52     /// <remarks>
  53     /// This coressponds to Windows' handling of command-line arguments as specified in:
  54     /// http://msdn.microsoft.com/library/17w5ykft
  55     /// </remarks>
  56     private static string EscapeArgument(string value)
  57     {
  58         if (value == null) return null;
  59
  60         // Add leading quotation mark if there are whitespaces
  61         bool containsWhitespace = ContainsWhitespace(value);
  62         StringBuilder result = containsWhitespace ? new StringBuilder("\"", value.Length + 2) : new StringBuilder(value.Length);
  63
  64         // Split by quotation marks
  65         string[] parts = value.Split('"');
  66         for (int i = 0; i < parts.Length; i++)
  67         {
  68             // Count slashes preceeding each quotation mark
  69             string slashesTrimmed = parts[i].TrimEnd('\\');
  70             int slashesCount = parts[i].Length - slashesTrimmed.Length;
  71
  72             result.Append(parts[i]);
  73
  74             if (i < parts.Length - 1)
  75             { // Not last part
  76                 for (int j = 0; j < slashesCount; j++) result.Append('\\'); // Double number of slashes
  77                 result.Append("\\\""); // Escaped quotation mark
  78             }
  79             else if (containsWhitespace)
  80             { // Last part if there are whitespaces
  81                 for (int j = 0; j < slashesCount; j++) result.Append('\\'); // Double number of slashes
  82                 result.Append('"'); // Non-escaped quotation mark
  83             }
  84         }
  85
  86         return result.ToString();
  87     }
  88
  89     /// <summary>
  90     /// Combines multiple strings into one for use as a Windows command-line argument using <see cref="EscapeArgument"/>.
  91     /// </summary>
  92     /// <param name="parts">The strings to be combines.</param>
  93     /// <remarks>
  94     /// This coressponds to Windows' handling of command-line arguments as specified in:
  95     /// http://msdn.microsoft.com/library/17w5ykft
  96     /// </remarks>
  97     private static string ConcatenateEscapeArgument(IEnumerable<string> parts)
  98     {
  99         if (parts == null) return null;
 100
 101         StringBuilder output = new StringBuilder();
 102         bool first = true;
 103         foreach (string part in parts)
 104         {
 105             // No separator before first or after last part
 106             if (first) first = false;
 107             else output.Append(' ');
 108
 109             output.Append(EscapeArgument(part));
 110         }
 111
 112         return output.ToString();
 113     }
 114
 115     /// <summary>
 116     /// Checks whether a string contains any whitespace characters
 117     /// </summary>
 118     private static bool ContainsWhitespace(string text)
 119     {
 120         return text.Contains(" ") || text.Contains("\t") || text.Contains("\n") || text.Contains("\r");
 121     }
 122     #endregion
 123 }