#!/usr/bin/perl -w
# (c) 2001, Dave Jones. <davej@suse.de> (the file handling bit)
# (c) 2005, Joel Scohpp <jschopp@austin.ibm.com> (the ugly bit)
# Licensed under the terms of the GNU GPL License version 2

use strict;

my @lines = ();
while (<>) {
	chomp;
	push(@lines, $_);
	if (eof(ARGV)) {
		process($ARGV, @lines);
		@lines = ();
	}
}

sub process {
	my $filename = shift;
	my @lines = @_;

	my $linenr=0;
	my $prevline="";


    my $clean = 1;
    
    # Trace the real file/line as we go.
    my $realfile = '';
    my $realline = 0;
    my $realcnt = 0;
    my $here = '';
	
    foreach my $line (@lines) {

		$linenr++;

#extract the filename as it passes
		if($line=~/^\+\+\+\s+(\S+)/) {
			$realfile=$1;
			next;
		}
#extract the line range in the file after the patch is applied
		if($line=~/^@@ -\d+,\d+ \+(\d+),(\d+) @@/) {
			$realline=$1-1;
			$realcnt=$2+1;
			next;
		}
#track the line number as we move thorugh the hunk
		if($line=~/^( |\+)/) {
			$realline++;
			$realcnt-- if ($realcnt);
		}
#ignore lines not being added
		if($line=~/^[^\+]/) {next;}

#make up the handle for any error we report on this line
		$here = "PATCH: $ARGV:$linenr:";
		$here .= "\nFILE: $realfile:$realline:" if ($realcnt);

# * goes on variable not on type
		if($line=~/[A-Za-z\d_]+\* [A-Za-z\d_]+/) {
		    print ("\"foo* bar\" should be \"foo *bar\"\n"); 
		    print "$linenr:\n$line\n\n";
		    $clean = 0;
		}

#trailing whitespace
		if($line=~/\S\s+$/) {
		    print ("trailing whitespace\n");
		    print "$here\n$line\n\n";
		    $clean = 0;
		}
#80 column limit
		my $lineforcounting;

		$lineforcounting = $line;
		$lineforcounting =~ s/^\+//;
		$lineforcounting =~ s/\t/        /;
		if(length($lineforcounting) > 80){
		    print "line over 80 characters\n";
		    print "$here\n$line\n\n";
		    $clean = 0;
		}
#function brace can't be on same line, except for #defines of do while, or if closed on same line
		if(($line=~/[A-Za-z\d_]+\**\s+\**[A-Za-z\d_]+\(.*\).* {/) and 
		    !($line=~/\#define.*do.*while/) and !($line=~/}/)){
		    print "braces following function declarations go on the next line\n";
		    print "$here\n$line\n\n";
		    $clean = 0;
		}
#need spaces around = in assignments unless they are in quotes
		if((($line=~/[A-Za-z\d_]+=/) or ($line=~/=[A-Za-z\d_]+/)) and !($line=~/\".*=.*\"/)) {
		    print ("need spaces around that =\n");
		    print "$here\n$line\n\n";
		}

#need space before brace following if, while, etc
		if($line=~/\(.*\){/) {
		    print ("need a space before the brace\n");
		    print "$here\n$line\n\n";
		    $clean = 0;		
		}

#gotos aren't indented
		if($line=~/^\+[ \t]+[A-Za-z\d_]+\s*:/){
		  print "Gotos should not be indented\n";
		  print "$here\n$line\n\n";
		  $clean = 0;
		}
#spaces vs tabs
		elsif($line=~/^\+ +[A-Za-z\d_]/) {
		    print ("use tabs not spaces\n");
		    print "$here\n$line\n\n";
		    $clean = 0;
		}
#studly caps, commented out until figure out how to distinguish between use of existing and adding new
#		if(($line=~/[\w_][a-z\d]+[A-Z]/) and !($line=~/print/)) {
#		    print ("No studly caps, use _\n");
#		    print "$here\n$line\n\n";
#		    $clean = 0;
#		}
#no spaces allowed after \ in define
		if($line=~/\#define.*\\\s$/){
		    print("Whitepspace after \\ makes next lines useless\n");
		    print "$here\n$line\n\n";
		    $clean = 0;
		}
		
#if/while/etc brace do not go on next line, unless #defining a do while loop, or if that brace on the next line is for something else
		if ($prevline=~/(if|while|for)\s*\(/) {
		    my @opened = $prevline=~/\(/g;
		    my @closed = $prevline=~/\)/g;
		    my $nr_line = $linenr;
		    my $next_line = $line;
		    my $extra_lines = 0;

		    while (scalar @opened > scalar @closed) {
		      $prevline .= $next_line;
		      $next_line = $lines[$nr_line];
		      $nr_line++;
		      #This test is here to take into account the contextual lines
		      # i.e. lines not added to the file
		      # Normally there are 3 contextual lines before/after the modified lines
		      if (!$next_line=~/^\+/) {
			if ($extra_lines < 3) {
			  $extra_lines++;
			} else {
			  last;
			}
		      }

		      @opened = $prevline=~/\(/g;
		      @closed = $prevline=~/\)/g;
		    }

		    if(($prevline=~/(if|while|for)\s*\(.*\)\s*$/) and ($next_line=~/{/) and !($next_line=~/(if|while|for)/) and
		       !($next_line=~/\#define.*do.*while/)) {
		      print "test: $lines[$linenr-1]\n";

		      print "\'$prevline\' \'$line\'";
		      print "That { should be on the previous line\n";
		      print "$here\n$line\n\n";
		      $clean = 0;
		    }
		  }

#multiline macros should be enclosed in a do while loop
		      if(($prevline=~/\#define.*\\/) and ($line=~/\\/) and !($line=~/do.*{/)){
			  print "Macros with multiple statements should be enclosed in a do - while loop\n";
			  print "$here\n$line\n\n";
			  $clean = 0;
		      }


#assignment in an if or while statement not soo good
			 if($line=~/(if|while)\(.*\s=\s.*\)/){
			     print "Assignment inside of if statements is generally frowned upon\n";
			     print "$here\n$line\n\n";
			     $clean = 0;
			 }


#prevline
		   $prevline = $line;
	       
	}


		   if($clean == 1){
		       print "Your patch is now worthy to be reviewed by a real person\n";
		       print "This small program couldn't find anything wrong\n";
		       print "Not to say there isn't anything wrong, but you are off to a good start\n";
		       print "If you find any style errors that this program missed please send them to \n";
		       print "Joel Schopp <jschopp\@austin.ibm.com> so he can try to incorporate them\n"
		   }
		   if($clean == 0){
		       print "If any of these errors are false positives please send them to\n";
		       print "Joel Schopp <jschopp\@austin.ibm.com> so he can fix things.";
		   }
	return 1;
}