# ABSTRACT: Report errors from perspective of caller of a "clan" of modules
##
## Based on Carp.pm from Perl 5.005_03.
## Last modified 22-May-2016 by Kent Fredric.
## Should be reasonably backwards compatible.
##
## This module is free software and can
## be used, modified and redistributed
## under the same terms as Perl itself.
##
@DB::args = (); # Avoid warning "used only once" in Perl 5.003
package Carp::Clan; # git description: v6.07-8-g8b5dba6
use strict;
use overload ();
# Original comments by Andy Wardley <abw@kfs.org> 09-Apr-1998.
# The $Max(EvalLen|(Arg(Len|Nums)) variables are used to specify how
# the eval text and function arguments should be formatted when printed.
our $MaxEvalLen = 0; # How much eval '...text...' to show. 0 = all.
our $MaxArgLen = 64; # How much of each argument to print. 0 = all.
our $MaxArgNums = 8; # How many arguments to print. 0 = all.
our $Verbose = 0; # If true then make _shortmsg call _longmsg instead.
our $VERSION = '6.08';
# _longmsg() crawls all the way up the stack reporting on all the function
# calls made. The error string, $error, is originally constructed from the
# arguments passed into _longmsg() via confess(), cluck() or _shortmsg().
# This gets appended with the stack trace messages which are generated for
# each function call on the stack.
sub _longmsg {
return (@_) if ( ref $_[0] );
local $_; # Protect surrounding program - just in case...
my ( $pack, $file, $line, $sub, $hargs, $eval, $require, @parms, $push );
my $error = join( '', @_ );
my $msg = '';
my $i = 0;
while (
do {
{
package # hide from PAUSE
DB;
( $pack, $file, $line, $sub, $hargs, undef, $eval, $require )
= caller( $i++ )
}
}
)
{
next if ( $pack eq 'Carp::Clan' );
if ( $error eq '' ) {
if ( defined $eval ) {
$eval =~ s/([\\\'])/\\$1/g unless ($require); # Escape \ and '
$eval
=~ s/([\x00-\x1F\x7F-\xFF])/sprintf("\\x%02X",ord($1))/eg;
substr( $eval, $MaxEvalLen ) = '...'
if ( $MaxEvalLen && length($eval) > $MaxEvalLen );
if ($require) { $sub = "require $eval"; }
else { $sub = "eval '$eval'"; }
}
elsif ( $sub eq '(eval)' ) { $sub = 'eval {...}'; }
else {
@parms = ();
if ($hargs) {
$push = 0;
@parms = @DB::args
; # We may trash some of the args so we take a copy
if ( $MaxArgNums and @parms > $MaxArgNums ) {
$#parms = $MaxArgNums;
pop(@parms);
$push = 1;
}
for (@parms) {
if ( defined $_ ) {
if ( ref $_ ) {
$_ = overload::StrVal($_);
}
else {
unless ( /^-?\d+(?:\.\d+(?:[eE][+-]\d+)?)?$/
) # Looks numeric
{
s/([\\\'])/\\$1/g; # Escape \ and '
s/([\x00-\x1F\x7F-\xFF])/sprintf("\\x%02X",ord($1))/eg;
substr( $_, $MaxArgLen ) = '...'
if ( $MaxArgLen
and length($_) > $MaxArgLen );
$_ = "'$_'";
}
}
}
else { $_ = 'undef'; }
}
push( @parms, '...' ) if ($push);
}
$sub .= '(' . join( ', ', @parms ) . ')';
}
if ( $msg eq '' ) { $msg = "$sub called"; }
else { $msg .= "\t$sub called"; }
}
else {
$msg = quotemeta($sub);
if ( $error =~ /\b$msg\b/ ) { $msg = $error; }
else {
if ( $sub =~ /::/ ) { $msg = "$sub(): $error"; }
else { $msg = "$sub: $error"; }
}
}
$msg .= " at $file line $line\n" unless ( $error =~ /\n$/ );
$error = '';
}
$msg ||= $error;
$msg =~ tr/\0//d; # Circumvent die's incorrect handling of NUL characters
$msg;
}
# _shortmsg() is called by carp() and croak() to skip all the way up to
# the top-level caller's package and report the error from there. confess()
# and cluck() generate a full stack trace so they call _longmsg() to
# generate that. In verbose mode _shortmsg() calls _longmsg() so you
# always get a stack trace.
sub _shortmsg {
my $pattern = shift;
my $verbose = shift;
return (@_) if ( ref $_[0] );
goto &_longmsg if ( $Verbose or $verbose );
my ( $pack, $file, $line, $sub );
my $error = join( '', @_ );
my $msg = '';
my $i = 0;
while ( ( $pack, $file, $line, $sub ) = caller( $i++ ) ) {
next if ( $pack eq 'Carp::Clan' or $pack =~ /$pattern/ );
if ( $error eq '' ) { $msg = "$sub() called"; }
else {
$msg = quotemeta($sub);
if ( $error =~ /\b$msg\b/ ) { $msg = $error; }
else {
if ( $sub =~ /::/ ) { $msg = "$sub(): $error"; }
else { $msg = "$sub: $error"; }
}
}
$msg .= " at $file line $line\n" unless ( $error =~ /\n$/ );
$msg =~ tr/\0//d; # Circumvent die's incorrect handling of NUL characters
return $msg;
}
goto &_longmsg;
}
# In the two identical regular expressions (immediately after the two occurrences of
# "quotemeta") above, the "\b ... \b" helps to avoid confusion between function names
# which are prefixes of each other, e.g. "My::Class::print" and "My::Class::println".
# The following four functions call _longmsg() or _shortmsg() depending on
# whether they should generate a full stack trace (confess() and cluck())
# or simply report the caller's package (croak() and carp()), respectively.
# confess() and croak() die, carp() and cluck() warn.
# Following code kept for calls with fully qualified subroutine names:
# (For backward compatibility with the original Carp.pm)
sub croak {
my $callpkg = caller(0);
my $pattern = ( $callpkg eq 'main' ) ? '^:::' : "^$callpkg\$";
die _shortmsg( $pattern, 0, @_ );
}
sub confess { die _longmsg(@_); }
sub carp {
my $callpkg = caller(0);
my $pattern = ( $callpkg eq 'main' ) ? '^:::' : "^$callpkg\$";
warn _shortmsg( $pattern, 0, @_ );
}
sub cluck { warn _longmsg(@_); }
# The following method imports a different closure for every caller.
# I.e., different modules can use this module at the same time
# and in parallel and still use different patterns.
sub import {
my $pkg = shift;
my $callpkg = caller(0);
my $pattern = ( $callpkg eq 'main' ) ? '^:::' : "^$callpkg\$";
my $verbose = 0;
my $item;
my $file;
for $item (@_) {
if ( $item =~ /^\d/ ) {
if ( $VERSION < $item ) {
$file = "$pkg.pm";
$file =~ s!::!/!g;
$file = $INC{$file};
die _shortmsg( '^:::', 0,
"$pkg $item required--this is only version $VERSION ($file)"
);
}
}
elsif ( $item =~ /^verbose$/i ) { $verbose = 1; }
else { $pattern = $item; }
}
eval { $pattern = qr/$pattern/ };
if ($@) {
$@ =~ s/\s+$//;
$@ =~ s/\s+at\s.+$//;
die _shortmsg( '^:::', 0, $@ );
}
{
local ($^W) = 0;
no strict "refs";
*{"${callpkg}::croak"} = sub { die _shortmsg( $pattern, $verbose, @_ ); };
*{"${callpkg}::confess"} = sub { die _longmsg ( @_ ); };
*{"${callpkg}::carp"} = sub { warn _shortmsg( $pattern, $verbose, @_ ); };
*{"${callpkg}::cluck"} = sub { warn _longmsg ( @_ ); };
}
}
1;
__END__
=pod
=encoding UTF-8
=head1 NAME
Carp::Clan - Report errors from perspective of caller of a "clan" of modules
=head1 VERSION
version 6.08
=head1 SYNOPSIS
carp - warn of errors (from perspective of caller)
cluck - warn of errors with stack backtrace
croak - die of errors (from perspective of caller)
confess - die of errors with stack backtrace
use Carp::Clan qw(^MyClan::);
croak "We're outta here!";
use Carp::Clan;
confess "This is how we got here!";
=head1 DESCRIPTION
This module is based on "C<Carp.pm>" from Perl 5.005_03. It has been
modified to skip all package names matching the pattern given in
the "use" statement inside the "C<qw()>" term (or argument list).
Suppose you have a family of modules or classes named "Pack::A",
"Pack::B" and so on, and each of them uses "C<Carp::Clan qw(^Pack::);>"
(or at least the one in which the error or warning gets raised).
Thus when for example your script "tool.pl" calls module "Pack::A",
and module "Pack::A" calls module "Pack::B", an exception raised in
module "Pack::B" will appear to have originated in "tool.pl" where
"Pack::A" was called, and not in "Pack::A" where "Pack::B" was called,
as the unmodified "C<Carp.pm>" would try to make you believe C<:-)>.
This works similarly if "Pack::B" calls "Pack::C" where the
exception is raised, et cetera.
In other words, this blames all errors in the "C<Pack::*>" modules
on the user of these modules, i.e., on you. C<;-)>
The skipping of a clan (or family) of packages according to a pattern
describing its members is necessary in cases where these modules are
not classes derived from each other (and thus when examining C<@ISA>
- as in the original "C<Carp.pm>" module - doesn't help).
The purpose and advantage of this is that a "clan" of modules can work
together (and call each other) and throw exceptions at various depths
down the calling hierarchy and still appear as a monolithic block (as
though they were a single module) from the perspective of the caller.
In case you just want to ward off all error messages from the module
in which you "C<use Carp::Clan>", i.e., if you want to make all error
messages or warnings to appear to originate from where your module
was called (this is what you usually used to "C<use Carp;>" for C<;-)>),
instead of in your module itself (which is what you can do with a
"die" or "warn" anyway), you do not need to provide a pattern,
the module will automatically provide the correct one for you.
I.e., just "C<use Carp::Clan;>" without any arguments and call "carp"
or "croak" as appropriate, and they will automatically defend your
module against all blames!
In other words, a pattern is only necessary if you want to make
several modules (more than one) work together and appear as though
they were only one.
=head2 Forcing a Stack Trace
As a debugging aid, you can force "C<Carp::Clan>" to treat a "croak" as
a "confess" and a "carp" as a "cluck". In other words, force a detailed
stack trace to be given. This can be very helpful when trying to
understand why, or from where, a warning or error is being generated.
This feature is enabled either by "importing" the non-existent symbol
'verbose', or by setting the global variable "C<$Carp::Clan::Verbose>"
to a true value.
You would typically enable it by saying
use Carp::Clan qw(verbose);
Note that you can both specify a "family pattern" and the string "verbose"
inside the "C<qw()>" term (or argument list) of the "use" statement, but
consider that a pattern of packages to skip is pointless when "verbose"
causes a full stack trace anyway.
=head1 BUGS
The "C<Carp::Clan>" routines don't handle exception objects currently.
If called with a first argument that is a reference, they simply
call "C<die()>" or "C<warn()>", as appropriate.
Bugs may be submitted through L<the RT bug tracker|https://rt.cpan.org/Public/Dist/Display.html?Name=Carp-Clan>
(or L<bug-Carp-Clan@rt.cpan.org|mailto:bug-Carp-Clan@rt.cpan.org>).
=head1 AUTHOR
Steffen Beyer <STBEY@cpan.org>
=head1 CONTRIBUTORS
=for stopwords Karen Etheridge Joshua ben Jore Kent Fredric
=over 4
=item *
Karen Etheridge <ether@cpan.org>
=item *
Joshua ben Jore <jjore@cpan.org>
=item *
Kent Fredric <kentnl@cpan.org>
=back
=head1 COPYRIGHT AND LICENSE
This software is copyright (c) 2001 by Steffen Beyer, Joshua ben Jore.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
=cut