scripts/cleanpatch

   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
   7 use bytes;
   8 use File::Basename;
   9
  10 # Default options
  11 $max_width = 79;
  12
  13 # Clean up space-tab sequences, either by removing spaces or
  14 # replacing them with tabs.
  15 sub clean_space_tabs($)
  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 $lo;
  51 }
  52
  53 # Compute the visual width of a string
  54 sub strwidth($) {
  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($0);
  79
  80 @files = ();
  81
  82 while (defined($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
  95 foreach $f ( @files ) {
  96     print STDERR "$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 }