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