home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
PC World 2005 June
/
PCWorld_2005-06_cd.bin
/
software
/
vyzkuste
/
firewally
/
firewally.exe
/
framework-2.3.exe
/
Lint.pm
< prev
next >
Wrap
Text File
|
2003-11-07
|
10KB
|
392 lines
package B::Lint;
our $VERSION = '1.02';
=head1 NAME
B::Lint - Perl lint
=head1 SYNOPSIS
perl -MO=Lint[,OPTIONS] foo.pl
=head1 DESCRIPTION
The B::Lint module is equivalent to an extended version of the B<-w>
option of B<perl>. It is named after the program B<lint> which carries
out a similar process for C programs.
=head1 OPTIONS AND LINT CHECKS
Option words are separated by commas (not whitespace) and follow the
usual conventions of compiler backend options. Following any options
(indicated by a leading B<->) come lint check arguments. Each such
argument (apart from the special B<all> and B<none> options) is a
word representing one possible lint check (turning on that check) or
is B<no-foo> (turning off that check). Before processing the check
arguments, a standard list of checks is turned on. Later options
override earlier ones. Available options are:
=over 8
=item B<context>
Produces a warning whenever an array is used in an implicit scalar
context. For example, both of the lines
$foo = length(@bar);
$foo = @bar;
will elicit a warning. Using an explicit B<scalar()> silences the
warning. For example,
$foo = scalar(@bar);
=item B<implicit-read> and B<implicit-write>
These options produce a warning whenever an operation implicitly
reads or (respectively) writes to one of Perl's special variables.
For example, B<implicit-read> will warn about these:
/foo/;
and B<implicit-write> will warn about these:
s/foo/bar/;
Both B<implicit-read> and B<implicit-write> warn about this:
for (@a) { ... }
=item B<bare-subs>
This option warns whenever a bareword is implicitly quoted, but is also
the name of a subroutine in the current package. Typical mistakes that it will
trap are:
use constant foo => 'bar';
@a = ( foo => 1 );
$b{foo} = 2;
Neither of these will do what a naive user would expect.
=item B<dollar-underscore>
This option warns whenever $_ is used either explicitly anywhere or
as the implicit argument of a B<print> statement.
=item B<private-names>
This option warns on each use of any variable, subroutine or
method name that lives in a non-current package but begins with
an underscore ("_"). Warnings aren't issued for the special case
of the single character name "_" by itself (e.g. $_ and @_).
=item B<undefined-subs>
This option warns whenever an undefined subroutine is invoked.
This option will only catch explicitly invoked subroutines such
as C<foo()> and not indirect invocations such as C<&$subref()>
or C<$obj-E<gt>meth()>. Note that some programs or modules delay
definition of subs until runtime by means of the AUTOLOAD
mechanism.
=item B<regexp-variables>
This option warns whenever one of the regexp variables $', $& or
$' is used. Any occurrence of any of these variables in your
program can slow your whole program down. See L<perlre> for
details.
=item B<all>
Turn all warnings on.
=item B<none>
Turn all warnings off.
=back
=head1 NON LINT-CHECK OPTIONS
=over 8
=item B<-u Package>
Normally, Lint only checks the main code of the program together
with all subs defined in package main. The B<-u> option lets you
include other package names whose subs are then checked by Lint.
=back
=head1 BUGS
This is only a very preliminary version.
This module doesn't work correctly on thread-enabled perls.
=head1 AUTHOR
Malcolm Beattie, mbeattie@sable.ox.ac.uk.
=cut
use strict;
use B qw(walkoptree_slow main_root walksymtable svref_2object parents
OPf_WANT_LIST OPf_WANT OPf_STACKED G_ARRAY SVf_POK
);
my $file = "unknown"; # shadows current filename
my $line = 0; # shadows current line number
my $curstash = "main"; # shadows current stash
# Lint checks
my %check;
my %implies_ok_context;
BEGIN {
map($implies_ok_context{$_}++,
qw(scalar av2arylen aelem aslice helem hslice
keys values hslice defined undef delete));
}
# Lint checks turned on by default
my @default_checks = qw(context);
my %valid_check;
# All valid checks
BEGIN {
map($valid_check{$_}++,
qw(context implicit_read implicit_write dollar_underscore
private_names bare_subs undefined_subs regexp_variables));
}
# Debugging options
my ($debug_op);
my %done_cv; # used to mark which subs have already been linted
my @extra_packages; # Lint checks mainline code and all subs which are
# in main:: or in one of these packages.
sub warning {
my $format = (@_ < 2) ? "%s" : shift;
warn sprintf("$format at %s line %d\n", @_, $file, $line);
}
# This gimme can't cope with context that's only determined
# at runtime via dowantarray().
sub gimme {
my $op = shift;
my $flags = $op->flags;
if ($flags & OPf_WANT) {
return(($flags & OPf_WANT) == OPf_WANT_LIST ? 1 : 0);
}
return undef;
}
sub B::OP::lint {}
sub B::COP::lint {
my $op = shift;
if ($op->name eq "nextstate") {
$file = $op->file;
$line = $op->line;
$curstash = $op->stash->NAME;
}
}
sub B::UNOP::lint {
my $op = shift;
my $opname = $op->name;
if ($check{context} && ($opname eq "rv2av" || $opname eq "rv2hv")) {
my $parent = parents->[0];
my $pname = $parent->name;
return if gimme($op) || $implies_ok_context{$pname};
# Two special cases to deal with: "foreach (@foo)" and "delete $a{$b}"
# null out the parent so we have to check for a parent of pp_null and
# a grandparent of pp_enteriter or pp_delete
if ($pname eq "null") {
my $gpname = parents->[1]->name;
return if $gpname eq "enteriter" || $gpname eq "delete";
}
warning("Implicit scalar context for %s in %s",
$opname eq "rv2av" ? "array" : "hash", $parent->desc);
}
if ($check{private_names} && $opname eq "method") {
my $methop = $op->first;
if ($methop->name eq "const") {
my $method = $methop->sv->PV;
if ($method =~ /^_/ && !defined(&{"$curstash\::$method"})) {
warning("Illegal reference to private method name $method");
}
}
}
}
sub B::PMOP::lint {
my $op = shift;
if ($check{implicit_read}) {
if ($op->name eq "match" && !($op->flags & OPf_STACKED)) {
warning('Implicit match on $_');
}
}
if ($check{implicit_write}) {
if ($op->name eq "subst" && !($op->flags & OPf_STACKED)) {
warning('Implicit substitution on $_');
}
}
}
sub B::LOOP::lint {
my $op = shift;
if ($check{implicit_read} || $check{implicit_write}) {
if ($op->name eq "enteriter") {
my $last = $op->last;
if ($last->name eq "gv" && $last->gv->NAME eq "_") {
warning('Implicit use of $_ in foreach');
}
}
}
}
sub B::SVOP::lint {
my $op = shift;
if ( $check{bare_subs} && $op->name eq 'const'
&& $op->private & 64 ) # OPpCONST_BARE = 64 in op.h
{
my $sv = $op->sv;
if( $sv->FLAGS & SVf_POK && exists &{$curstash.'::'.$sv->PV} ) {
warning "Bare sub name '" . $sv->PV . "' interpreted as string";
}
}
if ($check{dollar_underscore} && $op->name eq "gvsv"
&& $op->gv->NAME eq "_")
{
warning('Use of $_');
}
if ($check{private_names}) {
my $opname = $op->name;
if ($opname eq "gv" || $opname eq "gvsv") {
my $gv = $op->gv;
if ($gv->NAME =~ /^_./ && $gv->STASH->NAME ne $curstash) {
warning('Illegal reference to private name %s', $gv->NAME);
}
} elsif ($opname eq "method_named") {
my $method = $op->gv->PV;
if ($method =~ /^_./) {
warning("Illegal reference to private method name $method");
}
}
}
if ($check{undefined_subs}) {
if ($op->name eq "gv"
&& $op->next->name eq "entersub")
{
my $gv = $op->gv;
my $subname = $gv->STASH->NAME . "::" . $gv->NAME;
no strict 'refs';
if (!defined(&$subname)) {
$subname =~ s/^main:://;
warning('Undefined subroutine %s called', $subname);
}
}
}
if ($check{regexp_variables} && $op->name eq "gvsv") {
my $name = $op->gv->NAME;
if ($name =~ /^[&'`]$/) {
warning('Use of regexp variable $%s', $name);
}
}
}
sub B::GV::lintcv {
my $gv = shift;
my $cv = $gv->CV;
#warn sprintf("lintcv: %s::%s (done=%d)\n",
# $gv->STASH->NAME, $gv->NAME, $done_cv{$$cv});#debug
return if !$$cv || $done_cv{$$cv}++;
my $root = $cv->ROOT;
#warn " root = $root (0x$$root)\n";#debug
walkoptree_slow($root, "lint") if $$root;
}
sub do_lint {
my %search_pack;
walkoptree_slow(main_root, "lint") if ${main_root()};
# Now do subs in main
no strict qw(vars refs);
local(*glob);
for my $sym (keys %main::) {
next if $sym =~ /::$/;
*glob = $main::{$sym};
svref_2object(\*glob)->EGV->lintcv;
}
# Now do subs in non-main packages given by -u options
map { $search_pack{$_} = 1 } @extra_packages;
walksymtable(\%{"main::"}, "lintcv", sub {
my $package = shift;
$package =~ s/::$//;
#warn "Considering $package\n";#debug
return exists $search_pack{$package};
});
}
sub compile {
my @options = @_;
my ($option, $opt, $arg);
# Turn on default lint checks
for $opt (@default_checks) {
$check{$opt} = 1;
}
OPTION:
while ($option = shift @options) {
if ($option =~ /^-(.)(.*)/) {
$opt = $1;
$arg = $2;
} else {
unshift @options, $option;
last OPTION;
}
if ($opt eq "-" && $arg eq "-") {
shift @options;
last OPTION;
} elsif ($opt eq "D") {
$arg ||= shift @options;
foreach $arg (split(//, $arg)) {
if ($arg eq "o") {
B->debug(1);
} elsif ($arg eq "O") {
$debug_op = 1;
}
}
} elsif ($opt eq "u") {
$arg ||= shift @options;
push(@extra_packages, $arg);
}
}
foreach $opt (@default_checks, @options) {
$opt =~ tr/-/_/;
if ($opt eq "all") {
%check = %valid_check;
}
elsif ($opt eq "none") {
%check = ();
}
else {
if ($opt =~ s/^no_//) {
$check{$opt} = 0;
}
else {
$check{$opt} = 1;
}
warn "No such check: $opt\n" unless defined $valid_check{$opt};
}
}
# Remaining arguments are things to check
return \&do_lint;
}
1;