new version of the rename_rev.pl script

[Dan Carpenter]

rename_rev.pl is a script to strip away the mechanical changes that we
often see in staging patches and leave just the interesting changes for
manual review.

There are two new features in this version of rename_rev.pl.  The
-r <recipe> option let's you use some pre-written recipes.  There are
two recipes there now, "NULL" and "bool".  These are for changes where
people do:

-	if (foo == NULL) {
+	if (foo) {

Or you can use "cat patch.txt | rename_rev.pl -r bool" for the changes
like:

-	if (foo == true) {
+	if (foo) {

I am really worried about people reversing conditions when they write
these sorts of patches.  Hopefully, people can add some more recipes
for:

-	foo = 1 << 0;
+	foo = BIT(0);

And maybe:

-	frob(&(foo.bar));
+	frob(&foo.bar);

The second change in this version of rename_rev.pl is that I have
introduced the -a option for auto.  It's basically for when people deal
with CamelCase variables.  It tries to determine automatically what
variables were renamed and filter those changes away.  This is great
when you get a patch series of 80 patches that deal with CamelCase
variables.

regards,
dan carpenter


#!/usr/bin/perl

# This is a tool to help review variable rename patches. The goal is
# to strip out the automatic sed renames and the white space changes
# and leaves the interesting code changes.
#
# Example 1: A patch renames openInfo to open_info:
#     cat diff | rename_review.pl openInfo open_info
#
# Example 2: A patch swaps the first two arguments to some_func():
#     cat diff | rename_review.pl \
#                    -e 's/some_func\((.*?),(.*?),/some_func\($2, $1,/'
#
# Example 3: A patch removes the xkcd_ prefix from some but not all the
# variables.  Instead of trying to figure out which variables were renamed
# just remove the prefix from them all:
#     cat diff | rename_review.pl -ea 's/xkcd_//g'
#
# Example 4: A patch renames 20 CamelCase variables.  To review this let's
# just ignore all case changes and all '_' chars.
#     cat diff | rename_review -ea 'tr/[A-Z]/[a-z]/' -ea 's/_//g'
#
# The other arguments are:
# -nc removes comments
# -ns removes '\' chars if they are at the end of the line.

use strict;
use File::Temp qw/ :mktemp  /;

sub usage() {
    print "usage: cat diff | $0 old new old new old new...\n";
    print "   or: cat diff | $0 -e 's/old/new/g'\n";
    print " -a : auto";
    print " -e : execute on old lines\n";
    print " -ea: execute on all lines\n";
    print " -nc: no comments\n";
    print " -nb: no unneeded braces\n";
    print " -ns: no slashes at the end of a line\n";
    print " -pull: for function pull.  deletes context.\n";
    print " -r <recipe>: NULL, bool";
    exit(1);
}
my @subs;
my @strict_subs;
my @cmds;
my $strip_comments;
my $strip_braces;
my $strip_slashes;
my $pull_context;
my $auto;

sub filter($) {
    my $_ = shift();
    my $old = 0;
    if ($_ =~ /^-/) {
        $old = 1;
    }
    # remove the first char
    s/^[ +-]//;
    if ($strip_comments) {
        s/\/\*.*?\*\///g;
        s/\/\/.*//;
    }
    foreach my $cmd (@cmds) {
        if ($old || $cmd->[0] =~ /^-ea$/) {
            eval $cmd->[1];
        }
    }
    foreach my $sub (@subs) {
        if ($old) {
            s/$sub->[0]/$sub->[1]/g;
        }
    }
    foreach my $sub (@strict_subs) {
        if ($old) {
            s/\b$sub->[0]\b/$sub->[1]/g;
        }
    }

    # remove the newline so we can move curly braces here if we want.
    s/\n//;
    return $_;
}

while (my $param1 = shift()) {
    if ($param1 =~ /^-a$/) {
        $auto = 1;
        next;
    }
    if ($param1 =~ /^-nc$/) {
        $strip_comments = 1;
        next;
    }
    if ($param1 =~ /^-nb$/) {
        $strip_braces = 1;
        next;
    }
    if ($param1 =~ /^-ns$/) {
        $strip_slashes = 1;
        next;
    }
    if ($param1 =~ /^-pull$/) {
        $pull_context = 1;
        next;
    }
    my $param2 = shift();
    if ($param2 =~ /^$/) {
        usage();
    }
    if ($param1 =~ /^-e(a|)$/) {
        push @cmds, [$param1, $param2];
        next;
    }
    if ($param1 =~ /^-r$/) {
        if ($param2 =~ /bool/) {
            push @cmds, ["-e", "s/== true//"];
            push @cmds, ["-e", "s/true ==//"];
            push @cmds, ["-e", "s/([a-zA-Z\-\>\._]+) == false/!\$1/"];
            next;
        } elsif ($param2 =~ /NULL/) {
            push @cmds, ["-e", "s/ != NULL//"];
            push @cmds, ["-e", "s/([a-zA-Z\-\>\._]+) == NULL/!\$1/"];
            next;
        }
        usage();
    }

    push @subs, [$param1, $param2];
}

my ($oldfh, $oldfile) = mkstemp("/tmp/oldXXXXX");
my ($newfh, $newfile) = mkstemp("/tmp/newXXXXX");

my @input = <STDIN>;

# auto works on the observation that the - line comes before the + line when we
# rename variables.  Take the first - line.  Find the first + line.  Find the
# one word difference.  Test that the old word never occurs in the new text.
if ($auto) {
    my %c_keywords = (  auto => 1,
                        break => 1,
                        case => 1,
                        char => 1,
                        const => 1,
                        continue => 1,
                        default => 1,
                        do => 1,
                        double => 1,
                        else => 1,
                        enum => 1,
                        extern => 1,
                        float => 1,
                        for => 1,
                        goto => 1,
                        if => 1,
                        int => 1,
                        long => 1,
                        register => 1,
                        return => 1,
                        short => 1,
                        signed => 1,
                        sizeof => 1,
                        static => 1,
                        struct => 1,
                        switch => 1,
                        typedef => 1,
                        union => 1,
                        unsigned => 1,
                        void => 1,
                        volatile => 1,
                        while => 1);
    my %old_words;
    my %new_words;
    my %added_cmds;
    my @new_subs;

    my $inside = 0;
    foreach my $line (@input) {
        if ($line =~ /^(---|\+\+\+)/) {
            next;
        }

        if ($line =~ /^@/) {
            $inside = 1;
        }
        if ($inside && !(($_ =~ /^[- @+]/) || ($_ =~ /^$/))) {
            $inside = 0;
        }
        if (!$inside) {
            next;
        }

        if ($line =~ /^-/) {
            s/-//;
            my @words = split(/\W+/, $line);
            foreach my $word (@words) {
                $old_words{$word} = 1;
            }
        } elsif ($line =~ /^\+/) {
            s/\+//;
            my @words = split(/\W+/, $line);
            foreach my $word (@words) {
                $new_words{$word} = 1;
            }
        }
    }

    my $old_line;
    my $new_line;
    $inside = 0;
    foreach my $line (@input) {
        if ($line =~ /^(---|\+\+\+)/) {
            next;
        }

        if ($line =~ /^@/) {
            $inside = 1;
        }
        if ($inside && !(($_ =~ /^[- @+]/) || ($_ =~ /^$/))) {
            $inside = 0;
        }
        if (!$inside) {
            next;
        }


        if ($line =~ /^-/ && !$old_line) {
            s/^-//;
            $old_line = $line;
            next;
        } elsif ($old_line && $line =~ /^\+/) {
            s/^\+//;
            $new_line = $line;
        } else {
            next;
        }

        my @old_words = split(/\W+/, $old_line);
        my @new_words = split(/\W+/, $new_line);
        my @new_cmds;

        my $i;
        my $diff_count = 0;
        for ($i = 0; ; $i++) {
            if (!defined($old_words[$i]) && !defined($new_words[$i])) {
                last;
            }
            if (!defined($old_words[$i]) || !defined($new_words[$i])) {
                $diff_count = 1000;
                last;
            }
            if ($old_words[$i] eq $new_words[$i]) {
                next;
            }
            if ($c_keywords{$old_words[$i]}) {
                $diff_count = 1000;
                last;
            }
            if ($new_words{$old_words[$i]}) {
                $diff_count++;
            }
            push @new_cmds, [$old_words[$i], $new_words[$i]];
        }
        if ($diff_count <= 2) {
            foreach my $sub (@new_cmds) {
                if ($added_cmds{$sub->[0] . $sub->[1]}) {
                    next;
                }
                $added_cmds{$sub->[0] . $sub->[1]} = 1;
                push @new_subs, [$sub->[0] , $sub->[1]];
            }
        }

        $old_line = 0;
    }

    if (@new_subs) {
        print "RENAMES:\n";
        foreach my $sub (@new_subs) {
            print "$sub->[0] => $sub->[1]\n";
            push @strict_subs, [$sub->[0] , $sub->[1]];
        }
        print "---\n";
    }
}

my $output;

#recreate an old file and a new file
my $inside = 0;
foreach (@input) {
    if ($pull_context && !($_ =~ /^[+-@]/)) {
        next;
    }

    if ($_ =~ /^(---|\+\+\+)/) {
        next;
    }

    if ($_ =~ /^@/) {
        $inside = 1;
    }
    if ($inside && !(($_ =~ /^[- @+]/) || ($_ =~ /^$/))) {
        $inside = 0;
    }
    if (!$inside) {
        next;
    }

    $output = filter($_);

    if ($strip_braces && $_ =~ /^(\+|-)\W+{/) {
        $output =~ s/^[\t ]+(.*)/ $1/;
    } else {
        $output = "\n" . $output;
    }

    if ($_ =~ /^-/) {
        print $oldfh $output;
        next;
    }
    if ($_ =~ /^\+/) {
        print $newfh $output;
        next;
    }
    print $oldfh $output;
    print $newfh $output;

}
print $oldfh "\n";
print $newfh "\n";
# git diff puts a -- and version at the end of the diff.  put the -- into the
# new file as well so it's ignored
if ($output =~ /\n-/) {
    print $newfh "-\n";
}

my $hunk;
my $old_txt;
my $new_txt;

open diff, "diff -uw $oldfile $newfile |";
while (<diff>) {
    if ($_ =~ /^(---|\+\+\+)/) {
        next;
    }

    if ($_ =~ /^@/) {

        if ($strip_comments) {
            $old_txt =~ s/\/\*.*?\*\///g;
            $new_txt =~ s/\/\*.*?\*\///g;
        }
        if ($strip_braces) {
            $old_txt =~ s/{([^;{]*?);}/$1;/g;
            $new_txt =~ s/{([^;{]*?);}/$1;/g;
            # this is a hack because i don't know how to replace nested
            # unneeded curly braces.
            $old_txt =~ s/{([^;{]*?);}/$1;/g;
            $new_txt =~ s/{([^;{]*?);}/$1;/g;
        }

        if ($old_txt ne $new_txt) {
            print $hunk;
            print $_;
        }
        $hunk = "";
        $old_txt = "";
        $new_txt = "";
        next;
    }

    $hunk = $hunk . $_;

    if ($strip_slashes) {
        s/\\$//;
    }

    if ($_ =~ /^-/) {
        s/-//;
        s/[ \t\n]//g;
        $old_txt = $old_txt . $_;
        next;
    }
    if ($_ =~ /^\+/) {
        s/\+//;
        s/[ \t\n]//g;
        $new_txt = $new_txt . $_;
        next;
    }
    if ($_ =~ /^ /) {
        s/^ //;
        s/[ \t\n]//g;
        $old_txt = $old_txt . $_;
        $new_txt = $new_txt . $_;
    }
}

if ($old_txt ne $new_txt) {
    if ($strip_comments) {
        $old_txt =~ s/\/\*.*?\*\///g;
        $new_txt =~ s/\/\*.*?\*\///g;
    }
    if ($strip_braces) {
        $old_txt =~ s/{([^;{]*?);}/$1;/g;
        $new_txt =~ s/{([^;{]*?);}/$1;/g;
        $old_txt =~ s/{([^;{]*?);}/$1;/g;
        $new_txt =~ s/{([^;{]*?);}/$1;/g;
    }

    print $hunk;
}

unlink($oldfile);
unlink($newfile);

print "\ndone.\n";