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linux/scripts/headerdep.pl
Stephen Hemminger 1dcd810024 headerdep: perlcritic warning
Minor perlcritic warning:
headerdep.pl: "return" statement with explicit "undef" at line 84, column 2.  See page 199 of PBP.  (Severity: 5)

The rationale according to PBP is that an explicit return of undef
(contrary to most people's expectations) doesn't
always evaluate as false. It has to with the fact that perl return value
depends on context the function is called. If function is used in
list context, the appropriate return value for false is an empty list;
whereas in scalar context the return value for false is undefined.
By just using a "return" both cases are handled.

In the context of a trivial script this doesn't matter. But one script
may be cut-paste into later code (most people like me only know 50%
of perl), that is why perlcritic always complains

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2010-03-23 12:26:38 +01:00

193 lines
3.5 KiB
Perl
Executable File

#! /usr/bin/perl
#
# Detect cycles in the header file dependency graph
# Vegard Nossum <vegardno@ifi.uio.no>
#
use strict;
use warnings;
use Getopt::Long;
my $opt_all;
my @opt_include;
my $opt_graph;
&Getopt::Long::Configure(qw(bundling pass_through));
&GetOptions(
help => \&help,
version => \&version,
all => \$opt_all,
"I=s" => \@opt_include,
graph => \$opt_graph,
);
push @opt_include, 'include';
my %deps = ();
my %linenos = ();
my @headers = grep { strip($_) } @ARGV;
parse_all(@headers);
if($opt_graph) {
graph();
} else {
detect_cycles(@headers);
}
sub help {
print "Usage: $0 [options] file...\n";
print "\n";
print "Options:\n";
print " --all\n";
print " --graph\n";
print "\n";
print " -I includedir\n";
print "\n";
print "To make nice graphs, try:\n";
print " $0 --graph include/linux/kernel.h | dot -Tpng -o graph.png\n";
exit;
}
sub version {
print "headerdep version 2\n";
exit;
}
# Get a file name that is relative to our include paths
sub strip {
my $filename = shift;
for my $i (@opt_include) {
my $stripped = $filename;
$stripped =~ s/^$i\///;
return $stripped if $stripped ne $filename;
}
return $filename;
}
# Search for the file name in the list of include paths
sub search {
my $filename = shift;
return $filename if -f $filename;
for my $i (@opt_include) {
my $path = "$i/$filename";
return $path if -f $path;
}
return;
}
sub parse_all {
# Parse all the headers.
my @queue = @_;
while(@queue) {
my $header = pop @queue;
next if exists $deps{$header};
$deps{$header} = [] unless exists $deps{$header};
my $path = search($header);
next unless $path;
open(my $file, '<', $path) or die($!);
chomp(my @lines = <$file>);
close($file);
for my $i (0 .. $#lines) {
my $line = $lines[$i];
if(my($dep) = ($line =~ m/^#\s*include\s*<(.*?)>/)) {
push @queue, $dep;
push @{$deps{$header}}, [$i + 1, $dep];
}
}
}
}
sub print_cycle {
# $cycle[n] includes $cycle[n + 1];
# $cycle[-1] will be the culprit
my $cycle = shift;
# Adjust the line numbers
for my $i (0 .. $#$cycle - 1) {
$cycle->[$i]->[0] = $cycle->[$i + 1]->[0];
}
$cycle->[-1]->[0] = 0;
my $first = shift @$cycle;
my $last = pop @$cycle;
my $msg = "In file included";
printf "%s from %s,\n", $msg, $last->[1] if defined $last;
for my $header (reverse @$cycle) {
printf "%s from %s:%d%s\n",
" " x length $msg,
$header->[1], $header->[0],
$header->[1] eq $last->[1] ? ' <-- here' : '';
}
printf "%s:%d: warning: recursive header inclusion\n",
$first->[1], $first->[0];
}
# Find and print the smallest cycle starting in the specified node.
sub detect_cycles {
my @queue = map { [[0, $_]] } @_;
while(@queue) {
my $top = pop @queue;
my $name = $top->[-1]->[1];
for my $dep (@{$deps{$name}}) {
my $chain = [@$top, [$dep->[0], $dep->[1]]];
# If the dep already exists in the chain, we have a
# cycle...
if(grep { $_->[1] eq $dep->[1] } @$top) {
print_cycle($chain);
next if $opt_all;
return;
}
push @queue, $chain;
}
}
}
sub mangle {
$_ = shift;
s/\//__/g;
s/\./_/g;
s/-/_/g;
$_;
}
# Output dependency graph in GraphViz language.
sub graph {
print "digraph {\n";
print "\t/* vertices */\n";
for my $header (keys %deps) {
printf "\t%s [label=\"%s\"];\n",
mangle($header), $header;
}
print "\n";
print "\t/* edges */\n";
for my $header (keys %deps) {
for my $dep (@{$deps{$header}}) {
printf "\t%s -> %s;\n",
mangle($header), mangle($dep->[1]);
}
}
print "}\n";
}