cleanpatch: a script to clean up stealth whitespace added by a patch
This script is a companion to the "cleanfile" script. This cleans up a patch in unified diff format *before* it is applied. Note that the empty lines at the end of file detection *requires* that the diff was taken with at least one line of context around each hunk, or bad things will happen. This script cleans up various classes of stealth whitespace. In particular, it cleans up: - Whitespace (spaces or tabs)before newline; - DOS line endings (CR before LF); - Space before tab (spaces are deleted or converted to tabs); - Empty lines at end of file. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
This commit is contained in:
H. Peter Anvin
Sam Ravnborg
parent
12b315603a
commit
6e019b001d
1 changed files with 206 additions and 0 deletions
206
scripts/cleanpatch
Executable file
206
scripts/cleanpatch
Executable file
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#!/usr/bin/perl -w
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#
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# Clean a patch file -- or directory of patch files -- of stealth whitespace.
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# WARNING: this can be a highly destructive operation. Use with caution.
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#
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use bytes;
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use File::Basename;
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#
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# Clean up space-tab sequences, either by removing spaces or
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# replacing them with tabs.
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sub clean_space_tabs($)
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{
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no bytes; # Tab alignment depends on characters
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my($li) = @_;
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my($lo) = '';
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my $pos = 0;
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my $nsp = 0;
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my($i, $c);
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for ($i = 0; $i < length($li); $i++) {
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$c = substr($li, $i, 1);
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if ($c eq "\t") {
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my $npos = ($pos+$nsp+8) & ~7;
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my $ntab = ($npos >> 3) - ($pos >> 3);
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$lo .= "\t" x $ntab;
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$pos = $npos;
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$nsp = 0;
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} elsif ($c eq "\n" || $c eq "\r") {
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$lo .= " " x $nsp;
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$pos += $nsp;
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$nsp = 0;
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$lo .= $c;
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$pos = 0;
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} elsif ($c eq " ") {
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$nsp++;
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} else {
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$lo .= " " x $nsp;
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$pos += $nsp;
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$nsp = 0;
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$lo .= $c;
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$pos++;
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}
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}
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$lo .= " " x $nsp;
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return $lo;
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}
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$name = basename($0);
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foreach $f ( @ARGV ) {
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print STDERR "$name: $f\n";
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if (! -f $f) {
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print STDERR "$f: not a file\n";
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next;
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}
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if (!open(FILE, '+<', $f)) {
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print STDERR "$name: Cannot open file: $f: $!\n";
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next;
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}
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binmode FILE;
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# First, verify that it is not a binary file; consider any file
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# with a zero byte to be a binary file. Is there any better, or
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# additional, heuristic that should be applied?
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$is_binary = 0;
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while (read(FILE, $data, 65536) > 0) {
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if ($data =~ /\0/) {
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$is_binary = 1;
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last;
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}
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}
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if ($is_binary) {
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print STDERR "$name: $f: binary file\n";
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next;
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}
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seek(FILE, 0, 0);
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$in_bytes = 0;
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$out_bytes = 0;
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@lines = ();
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$in_hunk = 0;
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$err = 0;
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while ( defined($line = <FILE>) ) {
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$in_bytes += length($line);
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if (!$in_hunk) {
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if ($line =~ /^\@\@\s+\-([0-9]+),([0-9]+)\s+\+([0-9]+),([0-9]+)\s\@\@/) {
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$minus_lines = $2;
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$plus_lines = $4;
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if ($minus_lines || $plus_lines) {
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$in_hunk = 1;
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@hunk_lines = ($line);
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}
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} else {
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push(@lines, $line);
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$out_bytes += length($line);
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}
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} else {
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# We're in a hunk
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if ($line =~ /^\+/) {
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$plus_lines--;
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$text = substr($line, 1);
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$text =~ s/[ \t\r]*$//; # Remove trailing spaces
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$text = clean_space_tabs($text);
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push(@hunk_lines, '+'.$text);
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} elsif ($line =~ /^\-/) {
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$minus_lines--;
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push(@hunk_lines, $line);
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} elsif ($line =~ /^ /) {
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$plus_lines--;
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$minus_lines--;
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push(@hunk_lines, $line);
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} else {
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print STDERR "$name: $f: malformed patch\n";
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$err = 1;
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last;
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}
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if ($plus_lines < 0 || $minus_lines < 0) {
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print STDERR "$name: $f: malformed patch\n";
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$err = 1;
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last;
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} elsif ($plus_lines == 0 && $minus_lines == 0) {
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# End of a hunk. Process this hunk.
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my $i;
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my $l;
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my @h = ();
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my $adj = 0;
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my $done = 0;
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for ($i = scalar(@hunk_lines)-1; $i > 0; $i--) {
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$l = $hunk_lines[$i];
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if (!$done && $l eq "+\n") {
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$adj++; # Skip this line
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} elsif ($l =~ /^[ +]/) {
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$done = 1;
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unshift(@h, $l);
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} else {
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unshift(@h, $l);
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}
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}
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$l = $hunk_lines[0]; # Hunk header
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undef @hunk_lines; # Free memory
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if ($adj) {
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die unless
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($l =~ /^\@\@\s+\-([0-9]+),([0-9]+)\s+\+([0-9]+),([0-9]+)\s\@\@(.*)$/);
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my $mstart = $1;
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my $mlin = $2;
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my $pstart = $3;
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my $plin = $4;
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my $tail = $5; # doesn't include the final newline
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$l = sprintf("@@ -%d,%d +%d,%d @@%s\n",
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$mstart, $mlin, $pstart, $plin-$adj,
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$tail);
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}
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unshift(@h, $l);
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# Transfer to the output array
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foreach $l (@h) {
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$out_bytes += length($l);
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push(@lines, $l);
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}
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$in_hunk = 0;
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}
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}
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}
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if ($in_hunk) {
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print STDERR "$name: $f: malformed patch\n";
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$err = 1;
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}
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if (!$err) {
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if ($in_bytes != $out_bytes) {
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# Only write to the file if changed
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seek(FILE, 0, 0);
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print FILE @lines;
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if ( !defined($where = tell(FILE)) ||
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!truncate(FILE, $where) ) {
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die "$name: Failed to truncate modified file: $f: $!\n";
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}
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}
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}
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close(FILE);
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}
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