/usr/share/perl5/Class/ReturnValue.pm is in libclass-returnvalue-perl 0.55-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 | use warnings;
use strict;
package Class::ReturnValue;
=head1 NAME
Class::ReturnValue - A return-value object that lets you treat it
as as a boolean, array or object
=head1 DESCRIPTION
Class::ReturnValue is a "clever" return value object that can allow
code calling your routine to expect:
a boolean value (did it fail)
or a list (what are the return values)
=head1 EXAMPLE
sub demo {
my $value = shift;
my $ret = Class::ReturnValue->new();
$ret->as_array('0', 'No results found');
unless($value) {
$ret->as_error(errno => '1',
message => "You didn't supply a parameter.",
do_backtrace => 1);
}
return($ret->return_value);
}
if (demo('foo')){
print "the routine succeeded with one parameter";
}
if (demo()) {
print "The routine succeeded with 0 paramters. shouldn't happen";
} else {
print "The routine failed with 0 parameters (as it should).";
}
my $return = demo();
if ($return) {
print "The routine succeeded with 0 paramters. shouldn't happen";
} else {
print "The routine failed with 0 parameters (as it should). ".
"Stack trace:\n".
$return->backtrace;
}
my @return3 = demo('foo');
print "The routine got ".join(',',@return3).
"when asking for demo's results as an array";
my $return2 = demo('foo');
unless ($return2) {
print "The routine failed with a parameter. shouldn't happen.".
"Stack trace:\n".
$return2->backtrace;
}
my @return2_array = @{$return2}; # TODO: does this work
my @return2_array2 = $return2->as_array;
=cut
use Exporter;
use vars qw/$VERSION @EXPORT @ISA/;
@ISA = qw/Exporter/;
@EXPORT = qw /&return_value/;
use Carp;
use Devel::StackTrace;
use Data::Dumper;
$VERSION = '0.55';
use overload 'bool' => \&error_condition;
use overload '""' => \&error_condition;
use overload 'eq' => \&my_eq;
use overload '@{}' => \&as_array;
use overload 'fallback' => \&as_array;
=head1 METHODS
=item new
Instantiate a new Class::ReturnValue object
=cut
sub new {
my $self = {};
bless($self);
return($self);
}
sub my_eq {
my $self = shift;
if (wantarray()) {
return($self->as_array);
}
else {
return($self);
}
}
=item as_array
Return the 'as_array' attribute of this object as an array.
=cut
=item as_array [ARRAY]
If $self is called in an array context, returns the array specified in ARRAY
=cut
sub as_array {
my $self = shift;
if (@_) {
@{$self->{'as_array'}} = (@_);
}
return(@{$self->{'as_array'}});
}
=item as_error HASH
Turns this return-value object into an error return object. TAkes three parameters:
message
do_backtrace
errno
'message' is a human readable error message explaining what's going on
'do_backtrace' is a boolean. If it's true, a carp-style backtrace will be
stored in $self->{'backtrace'}. It defaults to true
errno and message default to undef. errno _must_ be specified.
It's a numeric error number. Any true integer value will cause the
object to evaluate to false in a scalar context. At first, this may look a
bit counterintuitive, but it means that you can have error codes and still
allow simple use of your functions in a style like this:
if ($obj->do_something) {
print "Yay! it worked";
} else {
print "Sorry. there's been an error.";
}
as well as more complex use like this:
my $retval = $obj->do_something;
if ($retval) {
print "Yay. we did something\n";
my ($foo, $bar, $baz) = @{$retval};
my $human_readable_return = $retval;
} else {
if ($retval->errno == 20) {
die "Failed with error 20 (Not enough monkeys).";
} else {
die $retval->backtrace; # Die and print out a backtrace
}
}
=cut
sub as_error {
my $self = shift;
my %args = ( errno => undef,
message => undef,
do_backtrace => 1,
@_);
unless($args{'errno'}) {
carp "$self -> as_error called without an 'errno' parameter";
return (undef);
}
$self->{'errno'} = $args{'errno'};
$self->{'error_message'} = $args{'message'};
if ($args{'do_backtrace'}) {
# Use carp's internal backtrace methods, rather than duplicating them ourselves
my $trace = Devel::StackTrace->new(ignore_package => 'Class::ReturnValue');
$self->{'backtrace'} = $trace->as_string; # like carp
}
return(1);
}
=item errno
Returns the errno if there's been an error. Otherwise, return undef
=cut
sub errno {
my $self = shift;
if ($self->{'errno'}) {
return ($self->{'errno'});
}
else {
return(undef);
}
}
=item error_message
If there's been an error return the error message.
=cut
sub error_message {
my $self = shift;
if ($self->{'error_message'}) {
return($self->{'error_message'});
}
else {
return(undef);
}
}
=item backtrace
If there's been an error and we asked for a backtrace, return the backtrace.
Otherwise, return undef.
=cut
sub backtrace {
my $self = shift;
if ($self->{'backtrace'}) {
return($self->{'backtrace'});
}
else {
return(undef);
}
}
=cut
=item error_condition
If there's been an error, return undef. Otherwise return 1
=cut
sub error_condition {
my $self = shift;
if ($self->{'errno'}) {
return (undef);
}
elsif (wantarray()) {
return(@{$self->{'as_array'}});
}
else {
return(1);
}
}
sub return_value {
my $self = shift;
if (wantarray) {
return ($self->as_array);
}
else {
return ($self);
}
}
=head1 AUTHOR
Jesse Vincent <jesse@bestpractical.com>
=head1 BUGS
This module has, as yet, not been used in production code. I thing
it should work, but have never benchmarked it. I have not yet used
it extensively, though I do plan to in the not-too-distant future.
If you have questions or comments, please write me.
If you need to report a bug, please send mail to
<bug-class-returnvalue@rt.cpan.org> or report your error on the web
at http://rt.cpan.org/
=head1 COPYRIGHT
Copyright (c) 2002,2003,2005,2007 Jesse Vincent <jesse@bestpractical.com>
You may use, modify, fold, spindle or mutilate this module under
the same terms as perl itself.
=head1 SEE ALSO
Class::ReturnValue isn't an exception handler. If it doesn't
do what you want, you might want look at one of the exception handlers
below:
Error, Exception, Exceptions, Exceptions::Class
You might also want to look at Contextual::Return, another implementation
of the same concept as this module.
=cut
1;
|