LEXECORP

I was asked for help with removing tabs from source code in a CVS repository. Simple I say. Well it was, with a couple of caveats.

WARNING: those with a weak bladder or IBS, start with single sample rcs files, then move up and work on a copy of your CVS repository before you try this at home!

With a little write, test and review I soon learnt

• they only wanted to address their C code (.h and .c) – and for that regex’s are so handy.
• obviously not their makefiles (those tabs are kind of important)! Always worth rebuilding / testing code once done.
• we’d better not touch any RCS files marked as binary either.
• we’ll not touch those cvsroot/CVSROOT admin files, no sources here anyway (nor should we mess around)
• script works best as root
• be careful with content that is rcs structure (we are touching source content only)

Here’s the code to modify a single rcs file or a complete repository. Actually I also realised that some people are slow to checkin, so I wrote another version to handle checked out files in home directories too. It’s basically the same but with no RCS tree structure to worry about. Again, be careful, don’t trash a groups checked out work, you’ll not be popular!

#!/usr/bin/perl

# NOTES:
# give it a directory or a single file
# won't touch anything with dir pattern 'cvsroot/CVSROOT'
# only .c & .h (won't touch make files (we need those tabs))
# try running with >& to capture the log, then tail -f on log file
#    or |& tee /usr/tmp/mylog.out 

sub basename {
 my( $path, $ext ) = @_;
 my( $name );

 ( $name = $path ) =~ s#.*/##;

 if ( ! $ext ) {
 $name =~ s#\..*$##;
 }

 $name;
}

sub useTmpFile {
 my ($newFile, $File ) = @_;

 $gid = 8096; #cvsadmin
 $uid = 0; #root
 $mode = 0444;  # -r--r--r-- 

 # move tmp file to live file
 system ("mv $newFile $File > /dev/null 2>&1");
 if ( $? != 0 ) {   
 warn "Couldn't mv $newFile $File";
 }

 $chmodcnt = chmod $mode, $File; # -r--r--r--
 if ( $chmodcnt != 1 ) {
   warn "Couldn't chmod mode=$mode file=$File"
 } 

 #MAKE FILE owned ROOT.CVSADMIN
 $chowncnt = chown $uid, $gid, $File;   #  `chown root.cvsadmin $f`;
 if ( $chowncnt != 1 ) {
   warn "Couldn't chown uid=$uid gid=$gid file=$File"
 }
 return;
}

sub convTabToSpaces {
 my ($tabLine) = $_;
 my ($idx);
 my $tab =  '    ';
 my $replace, $idx, $spaces;

 # index to 1st tab
 # index STR,SUBSTR,POSITION
 $idx = index ($tabLine, $tab , 0); #start pos of 1st tab

 while ( $idx  != -1 ) {
   $mod = $idx%8;
   if ( $mod != 0 ) {
     $spaces = ((int($idx/8)+1) * 8 ) - $idx;
   } else {
     $spaces = 8;
   }

   if ( $spaces == 1 ) {$replace = ' ';}
   if ( $spaces == 2 ) {$replace = '  ';}
   if ( $spaces == 3 ) {$replace = '   ';}
   if ( $spaces == 4 ) {$replace = '    ';}
   if ( $spaces == 5 ) {$replace = '     ';}
   if ( $spaces == 6 ) {$replace = '      ';}
   if ( $spaces == 7 ) {$replace = '       ';}
   if ( $spaces == 8 ) {$replace = '        ';}

   ($cnt) = $tabLine =~ s/\t/$replace/; # replace the first tab     

   $idx = index ($tabLine, $tab , $idx);

 } # while

 $tabLine;
}

sub detab {
 my ($file) = @_;
 open (IN, "<$file") || die "Can't open $file\n";

 $out = &basename($file, 1);
 open (OUT, ">/usr/tmp/$out") || die "Can't open $out\n";

 $datasect = 0;    
 $changedFile = 0; # file modified flag
 while ( <IN> ) {
   # handle text\n@ or text\n@@ -> we're modifying text not rcs structure
   if ( $_ =~ /^text$/ ) {
     print ( OUT "$_" );
     $tmp = <IN>;   
     #print ( OUT $tmp );
     if ( $tmp =~ /^\@\@$/ ) {
       $datasect = 0;
       print ( OUT $tmp );
     next;
   } else {  
     $datasect = 1;
     $_ = $tmp;
   }               
 } else {
   if ( ( $_ =~ /^\@\@$/ || $_ =~ /^\@$/ ) && $datasect == 1) {
     print ( OUT "$_" );
     $datasect = 0;    
     next;
   }
 }            

 if ( $datasect == 1 ) {
   $replace = '        '; # 8 spaces
   $tmpLine = $_;
   ($cnt) = $tmpLine =~ s/\t/$replace/g;          
   if ( $cnt ne "" ) {
     $changedFile = 1;
     $detabLine = convTabToSpaces($_);
     print ( OUT $detabLine );
   } else {
       print ( OUT $_ );
   }   

 } else {
   # not datasect so put out untouched
   print ( OUT "$_" );
 }
 } #input

 close(IN);
 close(OUT);

 if ( $changedFile == 1 ) {
   $main::fileCnt++;
   useTmpFile ("/usr/tmp/$out", $file);
   print "Replaced tabs in file $file\n";
   # debug start
   #system("rm /usr/tmp/$out");
   #if ( $? != 0 ) {   
   #    warn "Couldn't rm /usr/tmp/$out";
   #}
   # debug end
 } else {
   #cleanup
   system("rm /usr/tmp/$out");
   if ( $? != 0 ) {   
     warn "Couldn't rm /usr/tmp/$out";
   }
 }
 return;
}

# MAIN
######
# globals
$fileCnt = 0;

#AS ROOT ONLY
$me = getpwuid($<);
print "User: $me\n";
chop($host = `hostname`);
print "Host: $host\n";

if ($me ne "root" ) {
 die "must be root\n";
}

# TO RUN THRU e.g CVSROOT
if (@ARGV < 1){
 die "Gimme a CVSROOT_DIR or rcsFile\n";
} else {
 $dir = $ARGV[0]; print "your dir or file = $dir\n";
}

# GET ALL FILES
#                                   no directories
chop (@files = `find $dir -name \\* -type f -print `);
$totFileCnt = $#files+1;
print "Starting with $totFileCnt files\n";

$cmddir = "/usr/bin";

foreach $file ( @files ) {
 # don't touch the CVSROOT directory
 next if ( $file =~ /.*\/cvsroot\/CVSROOT.*/ );
 # only C stuff
 next unless $file =~ /.*\.c,.*/ || $file =~ /.*\.h,.*/; 

 $filetype = 'binary'; # default - don't touch
 # drop if a binary file
 open (RLOG, "$cmddir/rlog $file |") || die "Can't rlog $file\n";
 while (<RLOG>) {
   # last if ($_ =~ /^=.*=$/); #not needed
   if ($_ =~ /^keyword substitution: b.*$/ ) {
     #print "is a binary file\n";
     $filetype = 'binary';
     last;
   } else {
     if ($_ =~ /^keyword substitution: kv$/) {
     #print "is a normal file\n";
     $filetype = 'normal';
     last;
   }
 }

 }
 close(RLOG);

 if ($filetype eq 'normal') {
   detab $file;
 }
}

print "tab_fix.perl modified $fileCnt files\n";

exit;