linux/scripts/cleanpatch
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   1#!/usr/bin/env perl
   2# SPDX-License-Identifier: GPL-2.0
   3#
   4# Clean a patch file -- or directory of patch files -- of stealth whitespace.
   5# WARNING: this can be a highly destructive operation.  Use with caution.
   6#
   7
   8use warnings;
   9use bytes;
  10use File::Basename;
  11
  12# Default options
  13$max_width = 79;
  14
  15# Clean up space-tab sequences, either by removing spaces or
  16# replacing them with tabs.
  17sub clean_space_tabs($)
  18{
  19    no bytes;                   # Tab alignment depends on characters
  20
  21    my($li) = @_;
  22    my($lo) = '';
  23    my $pos = 0;
  24    my $nsp = 0;
  25    my($i, $c);
  26
  27    for ($i = 0; $i < length($li); $i++) {
  28        $c = substr($li, $i, 1);
  29        if ($c eq "\t") {
  30            my $npos = ($pos+$nsp+8) & ~7;
  31            my $ntab = ($npos >> 3) - ($pos >> 3);
  32            $lo .= "\t" x $ntab;
  33            $pos = $npos;
  34            $nsp = 0;
  35        } elsif ($c eq "\n" || $c eq "\r") {
  36            $lo .= " " x $nsp;
  37            $pos += $nsp;
  38            $nsp = 0;
  39            $lo .= $c;
  40            $pos = 0;
  41        } elsif ($c eq " ") {
  42            $nsp++;
  43        } else {
  44            $lo .= " " x $nsp;
  45            $pos += $nsp;
  46            $nsp = 0;
  47            $lo .= $c;
  48            $pos++;
  49        }
  50    }
  51    $lo .= " " x $nsp;
  52    return $lo;
  53}
  54
  55# Compute the visual width of a string
  56sub strwidth($) {
  57    no bytes;                   # Tab alignment depends on characters
  58
  59    my($li) = @_;
  60    my($c, $i);
  61    my $pos = 0;
  62    my $mlen = 0;
  63
  64    for ($i = 0; $i < length($li); $i++) {
  65        $c = substr($li,$i,1);
  66        if ($c eq "\t") {
  67            $pos = ($pos+8) & ~7;
  68        } elsif ($c eq "\n") {
  69            $mlen = $pos if ($pos > $mlen);
  70            $pos = 0;
  71        } else {
  72            $pos++;
  73        }
  74    }
  75
  76    $mlen = $pos if ($pos > $mlen);
  77    return $mlen;
  78}
  79
  80$name = basename($0);
  81
  82@files = ();
  83
  84while (defined($a = shift(@ARGV))) {
  85    if ($a =~ /^-/) {
  86        if ($a eq '-width' || $a eq '-w') {
  87            $max_width = shift(@ARGV)+0;
  88        } else {
  89            print STDERR "Usage: $name [-width #] files...\n";
  90            exit 1;
  91        }
  92    } else {
  93        push(@files, $a);
  94    }
  95}
  96
  97foreach $f ( @files ) {
  98    print STDERR "$name: $f\n";
  99
 100    if (! -f $f) {
 101        print STDERR "$f: not a file\n";
 102        next;
 103    }
 104
 105    if (!open(FILE, '+<', $f)) {
 106        print STDERR "$name: Cannot open file: $f: $!\n";
 107        next;
 108    }
 109
 110    binmode FILE;
 111
 112    # First, verify that it is not a binary file; consider any file
 113    # with a zero byte to be a binary file.  Is there any better, or
 114    # additional, heuristic that should be applied?
 115    $is_binary = 0;
 116
 117    while (read(FILE, $data, 65536) > 0) {
 118        if ($data =~ /\0/) {
 119            $is_binary = 1;
 120            last;
 121        }
 122    }
 123
 124    if ($is_binary) {
 125        print STDERR "$name: $f: binary file\n";
 126        next;
 127    }
 128
 129    seek(FILE, 0, 0);
 130
 131    $in_bytes = 0;
 132    $out_bytes = 0;
 133    $lineno = 0;
 134
 135    @lines  = ();
 136
 137    $in_hunk = 0;
 138    $err = 0;
 139
 140    while ( defined($line = <FILE>) ) {
 141        $lineno++;
 142        $in_bytes += length($line);
 143
 144        if (!$in_hunk) {
 145            if ($line =~
 146                /^\@\@\s+\-([0-9]+),([0-9]+)\s+\+([0-9]+),([0-9]+)\s\@\@/) {
 147                $minus_lines = $2;
 148                $plus_lines = $4;
 149                if ($minus_lines || $plus_lines) {
 150                    $in_hunk = 1;
 151                    @hunk_lines = ($line);
 152                }
 153            } else {
 154                push(@lines, $line);
 155                $out_bytes += length($line);
 156            }
 157        } else {
 158            # We're in a hunk
 159
 160            if ($line =~ /^\+/) {
 161                $plus_lines--;
 162
 163                $text = substr($line, 1);
 164                $text =~ s/[ \t\r]*$//;         # Remove trailing spaces
 165                $text = clean_space_tabs($text);
 166
 167                $l_width = strwidth($text);
 168                if ($max_width && $l_width > $max_width) {
 169                    print STDERR
 170                        "$f:$lineno: adds line exceeds $max_width ",
 171                        "characters ($l_width)\n";
 172                }
 173
 174                push(@hunk_lines, '+'.$text);
 175            } elsif ($line =~ /^\-/) {
 176                $minus_lines--;
 177                push(@hunk_lines, $line);
 178            } elsif ($line =~ /^ /) {
 179                $plus_lines--;
 180                $minus_lines--;
 181                push(@hunk_lines, $line);
 182            } else {
 183                print STDERR "$name: $f: malformed patch\n";
 184                $err = 1;
 185                last;
 186            }
 187
 188            if ($plus_lines < 0 || $minus_lines < 0) {
 189                print STDERR "$name: $f: malformed patch\n";
 190                $err = 1;
 191                last;
 192            } elsif ($plus_lines == 0 && $minus_lines == 0) {
 193                # End of a hunk.  Process this hunk.
 194                my $i;
 195                my $l;
 196                my @h = ();
 197                my $adj = 0;
 198                my $done = 0;
 199
 200                for ($i = scalar(@hunk_lines)-1; $i > 0; $i--) {
 201                    $l = $hunk_lines[$i];
 202                    if (!$done && $l eq "+\n") {
 203                        $adj++; # Skip this line
 204                    } elsif ($l =~ /^[ +]/) {
 205                        $done = 1;
 206                        unshift(@h, $l);
 207                    } else {
 208                        unshift(@h, $l);
 209                    }
 210                }
 211
 212                $l = $hunk_lines[0];  # Hunk header
 213                undef @hunk_lines;    # Free memory
 214
 215                if ($adj) {
 216                    die unless
 217                        ($l =~ /^\@\@\s+\-([0-9]+),([0-9]+)\s+\+([0-9]+),([0-9]+)\s\@\@(.*)$/);
 218                    my $mstart = $1;
 219                    my $mlin = $2;
 220                    my $pstart = $3;
 221                    my $plin = $4;
 222                    my $tail = $5; # doesn't include the final newline
 223
 224                    $l = sprintf("@@ -%d,%d +%d,%d @@%s\n",
 225                                 $mstart, $mlin, $pstart, $plin-$adj,
 226                                 $tail);
 227                }
 228                unshift(@h, $l);
 229
 230                # Transfer to the output array
 231                foreach $l (@h) {
 232                    $out_bytes += length($l);
 233                    push(@lines, $l);
 234                }
 235
 236                $in_hunk = 0;
 237            }
 238        }
 239    }
 240
 241    if ($in_hunk) {
 242        print STDERR "$name: $f: malformed patch\n";
 243        $err = 1;
 244    }
 245
 246    if (!$err) {
 247        if ($in_bytes != $out_bytes) {
 248            # Only write to the file if changed
 249            seek(FILE, 0, 0);
 250            print FILE @lines;
 251
 252            if ( !defined($where = tell(FILE)) ||
 253                 !truncate(FILE, $where) ) {
 254                die "$name: Failed to truncate modified file: $f: $!\n";
 255            }
 256        }
 257    }
 258
 259    close(FILE);
 260}
 261