ClearCase triggers are supposed to force the users to follow the policy. They need to be laying at some tamper-proof location, so that nobody tries to short-circuit them. Right? Sort of…

A small exercise.

Let’s first make an unfriendly trigger.

print "Sorry, this trigger is always false!n";
exit 1;

We’ll make it a pre-checkout trigger.
Try it:

Works as expected.
Now, I can’t modify the trigger (tamper-proof, remember :-D), why not wrap around ccperl.exe? Sorry for not doing things elegantly, it’s just an example:

/*******************************************************************************
 *                                                                             *
 * This thing does almost nothing. If it's not called as a trigger it just     *
 * calls ccperl2.exe with the same arguments. If it's called as a trigger. it  *
 * returns true                                                                *
 *                                                                             *
 *******************************************************************************/

#include <process.h>
#include <string>
#include <stdlib.h>
#include <iostream>

using namespace std;

int main(int argc, char *argv[])
{
    string perlcall("C:\Progra~1\Rational\ClearCase\bin\ccperl2.exe");

    // pass all arguments to the script
    for (int i = 1; i < argc; i++)
    {
        perlcall+=" ";

        // Put back quotes...
        if (string(argv[i]).find(" ",0))
            perlcall+="\""+string(argv[i])+"\"";
        else
            perlcall+=argv[i];
    }

    int retVal= system(perlcall.c_str());
    if (getenv("CLEARCASE_TRTYPE_KIND") != NULL)
    {
        cout << "Well, now it's always true!!!" << endl;
        return 0;
    }
    else
    {
        return retVal;
    }
}

Of course, I could just have it return 0 without executing the trigger, but then, the screenshot below would be less self-explanatory ;-). So now, let’s rename ccperl.exe to ccperl2.exe, and use our fabricated ccperl.exe instead. Let’s see how it works.

And that’s it.

Sure that’s just one more thing to remember - don’t give users the rights to modify ClearCase bin directory. But if triggers are supposed to force user to do something, why is there’s no checking, whether ccperl.exe is really ccperl.exe and not some kind of a lousy wrapper?

Now, what is it that antivirus programs are supposed to do? Scan for viruses…. Scan for viruses, you say? Read the following and reconsider that:

10. ISSUE:
File operations invoked on IBM’s ClearCase file
system (MVFS) might cause our AV filter driver
to leak memory. Our driver can see folder OPEN
requests but never the CLOSE requests.

RESOLUTION:
The AV filter driver has been updated to exclude
file operations of IBM’s MVFS file system from
scanning operations.

Due to an apparent problem scanning files, our driver was updated not to scan them?!!

Hello? HELLO? I’m wondering if you guys at McAfee are actually reading what you write.

Here’s a link to that embarassing confession: VirusScan Enterprise 8.0i Patch 15 Readme

There’s “Compare with previous version” in the ClearCase context menu. Useful. But how much more useful would it be to compare with an arbitrary version! Of course, one could always do it in the version tree, but it’s a bit time consuming, for files with a lot of versions; Entering a version extended path on the other hand, would be daunting.

Before looking at the ClearCase context menu, here are the scripts that will do the things for us.

1. Here’s one that shows a list of labels and compares with the one chosen:

@rem = ' This is a perl script for NT.
@echo off
@ccperl "%~f0" %1
@goto endofperl
@rem ';

require File::Temp;
use File::Temp qw/ :POSIX /;

# create the temp file
($fh, $file) = tmpnam();

END 
{
  # get rid of the temp file at the end.
  close $fh;
  unlink($file) or die "Couldn't unlink $file : $!";
}

# quote for spaces
$ARGV[0]='"'.$ARGV[0].'"' if ($ARGV[0]=~/\s/);

$labels=`cleartool lshist -fmt \"\%l\" $ARGV[0]`;
$labels=~s/\)\(/\,/g;
$labels=~s/(\(|\))//g;

@labellist=split /\,\s*/,$labels;
@labellist=sort @labellist;

foreach $label (@labellist)
{
  $label.=",";
}

print $fh "@labellist";

if (!system("clearprompt list -outfile $file -dfile $file -prompt \"Select label to compare with\""))
{
  seek($fh, 0, 0); 
  $chosenlabel=< $fh>;
  print $file;

  `cleardlg \/diffother $ARGV[0] $ARGV[0]\@\@\\$chosenlabel`;
}
__END__
:endofperl

Create a file, say, complabel.cmd and copy & paste or get it here

2. For an arbitrary version, we just need to take the version-extended path and compare it with the path without the version:

@rem = ' This is a perl script for NT.
@echo off
@ccperl "%~f0" %1
@goto endofperl
@rem ';

# quote for spaces
if ($ARGV[0]=~/\s/)
{
  $ARGV[0]=~s/(.*)\@\@/\"\1\"\@\@/;
}

$ARGV[0]=~/(.*)\@\@/;
`cleardlg \/diffother $1 $ARGV[0]`;

__END__
:endofperl

Create comp.cmd and copy & paste or get it here

I haven’t played much with them, so there may be some quirks with strange characters, et al.

Now that we have perl scripts, let’s modify the context menus. Open ClearCase Context Menu Editor (Programs>Rational Software>Rational Clearcase>Context Menu Editor). We’ll create two menu choices (just enter what’s below):

1. Compare with a Label

Of course, you need to enter your own path to the complabel.cmd.

Browse into Version Tree:

This “@@” does the magic - take a path in dynamic view, add @@ and now you can browse the version tree and all labels. Someone sent this hack to CM Crossroads, I’d happily attribute him/her, can’t find it now, though…

Now, we add the entries under dynamic view file “Checked In” and “Checked Out”, and arrange them nicely

And that’s it for the Context Menu Editor, our entries should now appear in the context menu:

Warning!!! Lame!!! To finish the comparison with an arbitrary version, we will need to add a proper command to the windows context menu. Now, I don’t have time to learn how to write Windows shell extensions, to make it all nice and smooth. So I did it in a crude way - I created a shortcut to comp.cmd and added it to my SendTo:

Now, if you want to compare with an arbitrary version of a file - in the dynamic view select Browse into Version Tree, and then in the tree select “compare with me”:

And that’s all folks.