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From: Steven Simpson <ss@domain.invalid>
Newsgroups: comp.lang.java.programmer
Subject: Re: exec problem is JDK 1.7.0_21
Date: Tue, 23 Apr 2013 19:56:20 +0100
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On 23/04/13 10:48, Steven Simpson wrote:
> Does that work correctly for anything to be thrown at CommandLineToArgvW?

No, you idiot.

<http://msdn.microsoft.com/en-us/library/windows/desktop/bb776391%28v=vs.85%29.aspx>

If the argument is:

C:\foo bar\

...quotes are needed around it to escape the space:

"C:\foo bar\"

...but a quote at the end will be misinterpreted as a literal quote, and 
result in:

C:\foo bar"

...if it's allowed at all.  The documentation was not clear on whether 
quotes needed to be around the whole argument, or could be used within:

C:\foo" "bar

But then you have to watch for:

C:\foo\ bar\

...which has to be escaped as something like these:

C:\foo"\ "bar\
"C:\foo\ bar"\

The simplest option might be to do as before, but just put the 'final' 
quote immediately before any trailing backslashes:

import java.util.*;
import java.util.regex.*;

public final class WindowsArgumentGenerator {
     private WindowsArgumentGenerator() { }

     private static final Pattern slashSequence = Pattern.compile("(\\\\*)\"");

     private static final Pattern spaces = Pattern.compile("\\s");

     private static boolean needsQuotes(CharSequence s) {
         return spaces.matcher(s).find();
     }

     public static String
         generateWindowsArgument(List<? extends CharSequence> args) {
         StringBuilder out = new StringBuilder();
         String sep = "";

         for (final CharSequence arg : args) {
             out.append(sep);
             sep = " ";

             final boolean quoted = needsQuotes(arg);
             if (quoted)
                 out.append('"');

             final int startOffset = out.length();

             Matcher m = slashSequence.matcher(arg);
             int lastEnd = 0;
             while (m.find()) {
                 out.append(arg.subSequence(lastEnd, m.start()));
                 lastEnd = m.end();

                 final String slashes = m.group(1);

                 /* Double the slashes and add one, then add the
                  * quote. */
                 out.append(slashes)
                     .append(slashes)
                     .append('\\')
                     .append("\"");
             }
             out.append(arg.subSequence(lastEnd, arg.length()));

             if (quoted) {
                 int i = out.length();
                 while (i > startOffset && out.charAt(i - 1) == '\\')
                     i--;
                 out.insert(i, '"');
             }
         }

         return out.toString();
     }

     public static void main(String[] args) throws Exception {
         for (int i = 0; i < args.length; i++)
             System.out.printf("argv[%d]=[%s]%n", i, args[i]);
         System.out.println(generateWindowsArgument(Arrays.asList(args)));
     }
}


Trying it out (in bash):

$ java WindowsArgumentGenerator 'hello world'
argv[0]=[hello world]
"hello world"
$ java WindowsArgumentGenerator '"hello world"'
argv[0]=["hello world"]
"\"hello world\""
$ java WindowsArgumentGenerator '"hello" "world"'
argv[0]=["hello" "world"]
"\"hello\" \"world\""
$ java WindowsArgumentGenerator 'hello" " world'
argv[0]=[hello" " world]
"hello\" \" world"
$ java WindowsArgumentGenerator 'hello' '""' 'world'
argv[0]=[hello]
argv[1]=[""]
argv[2]=[world]
hello \"\" world
$ java WindowsArgumentGenerator 'c:\program files\' 'world'
argv[0]=[c:\program files\]
argv[1]=[world]
"c:\program files"\ world
$ java WindowsArgumentGenerator 'c:\program files\\' 'world'
argv[0]=[c:\program files\\]
argv[1]=[world]
"c:\program files"\\ world
$ java WindowsArgumentGenerator 'c:\program files\\\' 'world'
argv[0]=[c:\program files\\\]
argv[1]=[world]
"c:\program files"\\\ world




-- 
ss at comp dot lancs dot ac dot uk