xref: /openbmc/linux/scripts/cleanpatch (revision 64c70b1c) 
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#
11# Clean up space-tab sequences, either by removing spaces or
12# replacing them with tabs.
13sub clean_space_tabs($)
14{
15    no bytes;			# Tab alignment depends on characters
16
17    my($li) = @_;
18    my($lo) = '';
19    my $pos = 0;
20    my $nsp = 0;
21    my($i, $c);
22
23    for ($i = 0; $i < length($li); $i++) {
24	$c = substr($li, $i, 1);
25	if ($c eq "\t") {
26	    my $npos = ($pos+$nsp+8) & ~7;
27	    my $ntab = ($npos >> 3) - ($pos >> 3);
28	    $lo .= "\t" x $ntab;
29	    $pos = $npos;
30	    $nsp = 0;
31	} elsif ($c eq "\n" || $c eq "\r") {
32	    $lo .= " " x $nsp;
33	    $pos += $nsp;
34	    $nsp = 0;
35	    $lo .= $c;
36	    $pos = 0;
37	} elsif ($c eq " ") {
38	    $nsp++;
39	} else {
40	    $lo .= " " x $nsp;
41	    $pos += $nsp;
42	    $nsp = 0;
43	    $lo .= $c;
44	    $pos++;
45	}
46    }
47    $lo .= " " x $nsp;
48    return $lo;
49}
50
51$name = basename($0);
52
53foreach $f ( @ARGV ) {
54    print STDERR "$name: $f\n";
55
56    if (! -f $f) {
57	print STDERR "$f: not a file\n";
58	next;
59    }
60
61    if (!open(FILE, '+<', $f)) {
62	print STDERR "$name: Cannot open file: $f: $!\n";
63	next;
64    }
65
66    binmode FILE;
67
68    # First, verify that it is not a binary file; consider any file
69    # with a zero byte to be a binary file.  Is there any better, or
70    # additional, heuristic that should be applied?
71    $is_binary = 0;
72
73    while (read(FILE, $data, 65536) > 0) {
74	if ($data =~ /\0/) {
75	    $is_binary = 1;
76	    last;
77	}
78    }
79
80    if ($is_binary) {
81	print STDERR "$name: $f: binary file\n";
82	next;
83    }
84
85    seek(FILE, 0, 0);
86
87    $in_bytes = 0;
88    $out_bytes = 0;
89
90    @lines  = ();
91
92    $in_hunk = 0;
93    $err = 0;
94
95    while ( defined($line = <FILE>) ) {
96	$in_bytes += length($line);
97
98	if (!$in_hunk) {
99	    if ($line =~ /^\@\@\s+\-([0-9]+),([0-9]+)\s+\+([0-9]+),([0-9]+)\s\@\@/) {
100		$minus_lines = $2;
101		$plus_lines = $4;
102		if ($minus_lines || $plus_lines) {
103		    $in_hunk = 1;
104		    @hunk_lines = ($line);
105		}
106	    } else {
107		push(@lines, $line);
108		$out_bytes += length($line);
109	    }
110	} else {
111	    # We're in a hunk
112
113	    if ($line =~ /^\+/) {
114		$plus_lines--;
115
116		$text = substr($line, 1);
117		$text =~ s/[ \t\r]*$//;		# Remove trailing spaces
118		$text = clean_space_tabs($text);
119
120		push(@hunk_lines, '+'.$text);
121	    } elsif ($line =~ /^\-/) {
122		$minus_lines--;
123		push(@hunk_lines, $line);
124	    } elsif ($line =~ /^ /) {
125		$plus_lines--;
126		$minus_lines--;
127		push(@hunk_lines, $line);
128	    } else {
129		print STDERR "$name: $f: malformed patch\n";
130		$err = 1;
131		last;
132	    }
133
134	    if ($plus_lines < 0 || $minus_lines < 0) {
135		print STDERR "$name: $f: malformed patch\n";
136		$err = 1;
137		last;
138	    } elsif ($plus_lines == 0 && $minus_lines == 0) {
139		# End of a hunk.  Process this hunk.
140		my $i;
141		my $l;
142		my @h = ();
143		my $adj = 0;
144		my $done = 0;
145
146		for ($i = scalar(@hunk_lines)-1; $i > 0; $i--) {
147		    $l = $hunk_lines[$i];
148		    if (!$done && $l eq "+\n") {
149			$adj++; # Skip this line
150		    } elsif ($l =~ /^[ +]/) {
151			$done = 1;
152			unshift(@h, $l);
153		    } else {
154			unshift(@h, $l);
155		    }
156		}
157
158		$l = $hunk_lines[0];  # Hunk header
159		undef @hunk_lines;    # Free memory
160
161		if ($adj) {
162		    die unless
163			($l =~ /^\@\@\s+\-([0-9]+),([0-9]+)\s+\+([0-9]+),([0-9]+)\s\@\@(.*)$/);
164		    my $mstart = $1;
165		    my $mlin = $2;
166		    my $pstart = $3;
167		    my $plin = $4;
168		    my $tail = $5; # doesn't include the final newline
169
170		    $l = sprintf("@@ -%d,%d +%d,%d @@%s\n",
171				 $mstart, $mlin, $pstart, $plin-$adj,
172				 $tail);
173		}
174		unshift(@h, $l);
175
176		# Transfer to the output array
177		foreach $l (@h) {
178		    $out_bytes += length($l);
179		    push(@lines, $l);
180		}
181
182		$in_hunk = 0;
183	    }
184	}
185    }
186
187    if ($in_hunk) {
188	print STDERR "$name: $f: malformed patch\n";
189	$err = 1;
190    }
191
192    if (!$err) {
193	if ($in_bytes != $out_bytes) {
194	    # Only write to the file if changed
195	    seek(FILE, 0, 0);
196	    print FILE @lines;
197
198	    if ( !defined($where = tell(FILE)) ||
199		 !truncate(FILE, $where) ) {
200		die "$name: Failed to truncate modified file: $f: $!\n";
201	    }
202	}
203    }
204
205    close(FILE);
206}
207