package File::stat;
use 5.006;

use strict;
use warnings;
use warnings::register;
use Carp;

BEGIN { *warnif = \&warnings::warnif }

our(@EXPORT, @EXPORT_OK, %EXPORT_TAGS);

our $VERSION = '1.07';

my @fields;
BEGIN {
use Exporter ();
@EXPORT = qw(stat lstat);
@fields = qw( $st_dev $st_ino $st_mode
$st_nlink $st_uid $st_gid
$st_rdev $st_size
$st_atime $st_mtime $st_ctime
$st_blksize $st_blocks
);
@EXPORT_OK = ( @fields, "stat_cando" );
%EXPORT_TAGS = ( FIELDS => [ @fields, @EXPORT ] );
}
use vars @fields;

use Fcntl qw(S_IRUSR S_IWUSR S_IXUSR);

BEGIN {
# These constants will croak on use if the platform doesn't define
# them. It's important to avoid inflicting that on the user.
no strict 'refs';
for (qw(suid sgid svtx)) {
my $val = eval { &{"Fcntl::S_I\U$_"} };
*{"_$_"} = defined $val ? sub { $_[0] & $val ? 1 : "" } : sub { "" };
}
for (qw(SOCK CHR BLK REG DIR LNK)) {
*{"S_IS$_"} = defined eval { &{"Fcntl::S_IF$_"} }
? \&{"Fcntl::S_IS$_"} : sub { "" };
}
# FIFO flag and macro don't quite follow the S_IF/S_IS pattern above
# RT #111638
*{"S_ISFIFO"} = defined &Fcntl::S_IFIFO
? \&Fcntl::S_ISFIFO : sub { "" };
}

# from doio.c
sub _ingroup {
my ($gid, $eff) = @_;

# I am assuming that since VMS doesn't have getgroups(2), $) will
# always only contain a single entry.
$^O eq "VMS" and return $_[0] == $);

my ($egid, @supp) = split " ", $);
my ($rgid) = split " ", $(;

$gid == ($eff ? $egid : $rgid) and return 1;
grep $gid == $_, @supp and return 1;

return "";
}

# VMS uses the Unix version of the routine, even though this is very
# suboptimal. VMS has a permissions structure that doesn't really fit
# into struct stat, and unlike on Win32 the normal -X operators respect
# that, but unfortunately by the time we get here we've already lost the
# information we need. It looks to me as though if we were to preserve
# the st_devnam entry of vmsish.h's fake struct stat (which actually
# holds the filename) it might be possible to do this right, but both
# getting that value out of the struct (perl's stat doesn't return it)
# and interpreting it later would require this module to have an XS
# component (at which point we might as well just call Perl_cando and
# have done with it).

if (grep $^O eq $_, qw/os2 MSWin32 dos/) {

# from doio.c
*cando = sub { ($_[0][2] & $_[1]) ? 1 : "" };
}
else {

# from doio.c
*cando = sub {
my ($s, $mode, $eff) = @_;
my $uid = $eff ? $> : $<;
my ($stmode, $stuid, $stgid) = @$s[2,4,5];

# This code basically assumes that the rwx bits of the mode are
# the 0777 bits, but so does Perl_cando.

if ($uid == 0 && $^O ne "VMS") {
# If we're root on unix
# not testing for executable status => all file tests are true
return 1 if !($mode & 0111);
# testing for executable status =>
# for a file, any x bit will do
# for a directory, always true
return 1 if $stmode & 0111 || S_ISDIR($stmode);
return "";
}

if ($stuid == $uid) {
$stmode & $mode and return 1;
}
elsif (_ingroup($stgid, $eff)) {
$stmode & ($mode >> 3) and return 1;
}
else {
$stmode & ($mode >> 6) and return 1;
}
return "";
};
}

# alias for those who don't like objects
*stat_cando = \&cando;

my %op = (
r => sub { cando($_[0], S_IRUSR, 1) },
w => sub { cando($_[0], S_IWUSR, 1) },
x => sub { cando($_[0], S_IXUSR, 1) },
o => sub { $_[0][4] == $> },

R => sub { cando($_[0], S_IRUSR, 0) },
W => sub { cando($_[0], S_IWUSR, 0) },
X => sub { cando($_[0], S_IXUSR, 0) },
O => sub { $_[0][4] == $< },

e => sub { 1 },
z => sub { $_[0][7] == 0 },
s => sub { $_[0][7] },

f => sub { S_ISREG ($_[0][2]) },
d => sub { S_ISDIR ($_[0][2]) },
l => sub { S_ISLNK ($_[0][2]) },
p => sub { S_ISFIFO($_[0][2]) },
S => sub { S_ISSOCK($_[0][2]) },
b => sub { S_ISBLK ($_[0][2]) },
c => sub { S_ISCHR ($_[0][2]) },

u => sub { _suid($_[0][2]) },
g => sub { _sgid($_[0][2]) },
k => sub { _svtx($_[0][2]) },

M => sub { ($^T - $_[0][9] ) / 86400 },
C => sub { ($^T - $_[0][10]) / 86400 },
A => sub { ($^T - $_[0][8] ) / 86400 },
);

use constant HINT_FILETEST_ACCESS => 0x00400000;

# we need fallback=>1 or stringifying breaks
use overload
fallback => 1,
-X => sub {
my ($s, $op) = @_;

if (index("rwxRWX", $op) >= 0) {
(caller 0)[8] & HINT_FILETEST_ACCESS
and warnif("File::stat ignores use filetest 'access'");

$^O eq "VMS" and warnif("File::stat ignores VMS ACLs");

# It would be nice to have a warning about using -l on a
# non-lstat, but that would require an extra member in the
# object.
}

if ($op{$op}) {
return $op{$op}->($_[0]);
}
else {
croak "-$op is not implemented on a File::stat object";
}
};

# Class::Struct forbids use of @ISA
sub import { goto &Exporter::import }

use Class::Struct qw(struct);
struct 'File::stat' => [
map { $_ => '$' } qw{
dev ino mode nlink uid gid rdev size
atime mtime ctime blksize blocks
}
];

sub populate (@) {
return unless @_;
my $stob = new();
@$stob = (
$st_dev, $st_ino, $st_mode, $st_nlink, $st_uid, $st_gid, $st_rdev,
$st_size, $st_atime, $st_mtime, $st_ctime, $st_blksize, $st_blocks )
= @_;
return $stob;
}

sub lstat ($) { populate(CORE::lstat(shift)) }

sub stat ($) {
my $arg = shift;
my $st = populate(CORE::stat $arg);
return $st if defined $st;
my $fh;
{
local $!;
no strict 'refs';
require Symbol;
$fh = \*{ Symbol::qualify( $arg, caller() )};
return unless defined fileno $fh;
}
return populate(CORE::stat $fh);
}

1;
__END__

=head1 NAME

File::stat - by-name interface to Perl's built-in stat() functions

=head1 SYNOPSIS

use File::stat;
$st = stat($file) or die "No $file: $!";
if ( ($st->mode & 0111) && $st->nlink > 1) ) {
print "$file is executable with lotsa links\n";
}

if ( -x $st ) {
print "$file is executable\n";
}

use Fcntl "S_IRUSR";
if ( $st->cando(S_IRUSR, 1) ) {
print "My effective uid can read $file\n";
}

use File::stat qw(:FIELDS);
stat($file) or die "No $file: $!";
if ( ($st_mode & 0111) && ($st_nlink > 1) ) {
print "$file is executable with lotsa links\n";
}

=head1 DESCRIPTION

This module's default exports override the core stat()
and lstat() functions, replacing them with versions that return
"File::stat" objects. This object has methods that
return the similarly named structure field name from the
stat(2) function; namely,
dev,
ino,
mode,
nlink,
uid,
gid,
rdev,
size,
atime,
mtime,
ctime,
blksize,
and
blocks.

As of version 1.02 (provided with perl 5.12) the object provides C<"-X">
overloading, so you can call filetest operators (C<-f>, C<-x>, and so
on) on it. It also provides a C<< ->cando >> method, called like

$st->cando( ACCESS, EFFECTIVE )

where I<ACCESS> is one of C<S_IRUSR>, C<S_IWUSR> or C<S_IXUSR> from the
L<Fcntl|Fcntl> module, and I<EFFECTIVE> indicates whether to use
effective (true) or real (false) ids. The method interprets the C<mode>,
C<uid> and C<gid> fields, and returns whether or not the current process
would be allowed the specified access.

If you don't want to use the objects, you may import the C<< ->cando >>
method into your namespace as a regular function called C<stat_cando>.
This takes an arrayref containing the return values of C<stat> or
C<lstat> as its first argument, and interprets it for you.

You may also import all the structure fields directly into your namespace
as regular variables using the :FIELDS import tag. (Note that this still
overrides your stat() and lstat() functions.) Access these fields as
variables named with a preceding C<st_> in front their method names.
Thus, C<$stat_obj-E<gt>dev()> corresponds to $st_dev if you import
the fields.

To access this functionality without the core overrides,
pass the C<use> an empty import list, and then access
function functions with their full qualified names.
On the other hand, the built-ins are still available
via the C<CORE::> pseudo-package.

=head1 BUGS

As of Perl 5.8.0 after using this module you cannot use the implicit
C<$_> or the special filehandle C<_> with stat() or lstat(), trying
to do so leads into strange errors. The workaround is for C<$_> to
be explicit

my $stat_obj = stat $_;

and for C<_> to explicitly populate the object using the unexported
and undocumented populate() function with CORE::stat():

my $stat_obj = File::stat::populate(CORE::stat(_));

=head1 ERRORS

=over 4

=item -%s is not implemented on a File::stat object

The filetest operators C<-t>, C<-T> and C<-B> are not implemented, as
they require more information than just a stat buffer.

=back

=head1 WARNINGS

These can all be disabled with

no warnings "File::stat";

=over 4

=item File::stat ignores use filetest 'access'

You have tried to use one of the C<-rwxRWX> filetests with C<use
filetest 'access'> in effect. C<File::stat> will ignore the pragma, and
just use the information in the C<mode> member as usual.

=item File::stat ignores VMS ACLs

VMS systems have a permissions structure that cannot be completely
represented in a stat buffer, and unlike on other systems the builtin
filetest operators respect this. The C<File::stat> overloads, however,
do not, since the information required is not available.

=back

=head1 NOTE

While this class is currently implemented using the Class::Struct
module to build a struct-like class, you shouldn't rely upon this.

=head1 AUTHOR

Tom Christiansen