mirror of https://github.com/tongzx/nt5src
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
276 lines
9.8 KiB
276 lines
9.8 KiB
package Carp;
|
|
|
|
=head1 NAME
|
|
|
|
carp - warn of errors (from perspective of caller)
|
|
|
|
cluck - warn of errors with stack backtrace
|
|
(not exported by default)
|
|
|
|
croak - die of errors (from perspective of caller)
|
|
|
|
confess - die of errors with stack backtrace
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
use Carp;
|
|
croak "We're outta here!";
|
|
|
|
use Carp qw(cluck);
|
|
cluck "This is how we got here!";
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
The Carp routines are useful in your own modules because
|
|
they act like die() or warn(), but report where the error
|
|
was in the code they were called from. Thus if you have a
|
|
routine Foo() that has a carp() in it, then the carp()
|
|
will report the error as occurring where Foo() was called,
|
|
not where carp() was called.
|
|
|
|
=head2 Forcing a Stack Trace
|
|
|
|
As a debugging aid, you can force Carp to treat a croak as a confess
|
|
and a carp as a cluck across I<all> modules. 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 by 'importing' the non-existant symbol
|
|
'verbose'. You would typically enable it by saying
|
|
|
|
perl -MCarp=verbose script.pl
|
|
|
|
or by including the string C<MCarp=verbose> in the L<PERL5OPT>
|
|
environment variable.
|
|
|
|
=cut
|
|
|
|
# This package is heavily used. Be small. Be fast. Be good.
|
|
|
|
# Comments added by Andy Wardley <[email protected]> 09-Apr-98, based on an
|
|
# _almost_ complete understanding of the package. Corrections and
|
|
# comments are welcome.
|
|
|
|
# The $CarpLevel variable can be set to "strip off" extra caller levels for
|
|
# those times when Carp calls are buried inside other functions. The
|
|
# $Max(EvalLen|(Arg(Len|Nums)) variables are used to specify how the eval
|
|
# text and function arguments should be formatted when printed.
|
|
|
|
$CarpLevel = 0; # How many extra package levels to skip on carp.
|
|
$MaxEvalLen = 0; # How much eval '...text...' to show. 0 = all.
|
|
$MaxArgLen = 64; # How much of each argument to print. 0 = all.
|
|
$MaxArgNums = 8; # How many arguments to print. 0 = all.
|
|
$Verbose = 0; # If true then make shortmess call longmess instead
|
|
|
|
require Exporter;
|
|
@ISA = ('Exporter');
|
|
@EXPORT = qw(confess croak carp);
|
|
@EXPORT_OK = qw(cluck verbose);
|
|
@EXPORT_FAIL = qw(verbose); # hook to enable verbose mode
|
|
|
|
|
|
# if the caller specifies verbose usage ("perl -MCarp=verbose script.pl")
|
|
# then the following method will be called by the Exporter which knows
|
|
# to do this thanks to @EXPORT_FAIL, above. $_[1] will contain the word
|
|
# 'verbose'.
|
|
|
|
sub export_fail {
|
|
shift;
|
|
$Verbose = shift if $_[0] eq 'verbose';
|
|
return @_;
|
|
}
|
|
|
|
|
|
# longmess() 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 longmess() via confess(), cluck() or shortmess().
|
|
# This gets appended with the stack trace messages which are generated for
|
|
# each function call on the stack.
|
|
|
|
sub longmess {
|
|
my $error = join '', @_;
|
|
my $mess = "";
|
|
my $i = 1 + $CarpLevel;
|
|
my ($pack,$file,$line,$sub,$hargs,$eval,$require);
|
|
my (@a);
|
|
#
|
|
# crawl up the stack....
|
|
#
|
|
while (do { { package DB; @a = caller($i++) } } ) {
|
|
# get copies of the variables returned from caller()
|
|
($pack,$file,$line,$sub,$hargs,undef,$eval,$require) = @a;
|
|
#
|
|
# if the $error error string is newline terminated then it
|
|
# is copied into $mess. Otherwise, $mess gets set (at the end of
|
|
# the 'else {' section below) to one of two things. The first time
|
|
# through, it is set to the "$error at $file line $line" message.
|
|
# $error is then set to 'called' which triggers subsequent loop
|
|
# iterations to append $sub to $mess before appending the "$error
|
|
# at $file line $line" which now actually reads "called at $file line
|
|
# $line". Thus, the stack trace message is constructed:
|
|
#
|
|
# first time: $mess = $error at $file line $line
|
|
# subsequent times: $mess .= $sub $error at $file line $line
|
|
# ^^^^^^
|
|
# "called"
|
|
if ($error =~ m/\n$/) {
|
|
$mess .= $error;
|
|
} else {
|
|
# Build a string, $sub, which names the sub-routine called.
|
|
# This may also be "require ...", "eval '...' or "eval {...}"
|
|
if (defined $eval) {
|
|
if ($require) {
|
|
$sub = "require $eval";
|
|
} else {
|
|
$eval =~ s/([\\\'])/\\$1/g;
|
|
if ($MaxEvalLen && length($eval) > $MaxEvalLen) {
|
|
substr($eval,$MaxEvalLen) = '...';
|
|
}
|
|
$sub = "eval '$eval'";
|
|
}
|
|
} elsif ($sub eq '(eval)') {
|
|
$sub = 'eval {...}';
|
|
}
|
|
# if there are any arguments in the sub-routine call, format
|
|
# them according to the format variables defined earlier in
|
|
# this file and join them onto the $sub sub-routine string
|
|
if ($hargs) {
|
|
# we may trash some of the args so we take a copy
|
|
@a = @DB::args; # must get local copy of args
|
|
# don't print any more than $MaxArgNums
|
|
if ($MaxArgNums and @a > $MaxArgNums) {
|
|
# cap the length of $#a and set the last element to '...'
|
|
$#a = $MaxArgNums;
|
|
$a[$#a] = "...";
|
|
}
|
|
for (@a) {
|
|
# set args to the string "undef" if undefined
|
|
$_ = "undef", next unless defined $_;
|
|
if (ref $_) {
|
|
# dunno what this is for...
|
|
$_ .= '';
|
|
s/'/\\'/g;
|
|
}
|
|
else {
|
|
s/'/\\'/g;
|
|
# terminate the string early with '...' if too long
|
|
substr($_,$MaxArgLen) = '...'
|
|
if $MaxArgLen and $MaxArgLen < length;
|
|
}
|
|
# 'quote' arg unless it looks like a number
|
|
$_ = "'$_'" unless /^-?[\d.]+$/;
|
|
# print high-end chars as 'M-<char>' or '^<char>'
|
|
s/([\200-\377])/sprintf("M-%c",ord($1)&0177)/eg;
|
|
s/([\0-\37\177])/sprintf("^%c",ord($1)^64)/eg;
|
|
}
|
|
# append ('all', 'the', 'arguments') to the $sub string
|
|
$sub .= '(' . join(', ', @a) . ')';
|
|
}
|
|
# here's where the error message, $mess, gets constructed
|
|
$mess .= "\t$sub " if $error eq "called";
|
|
$mess .= "$error at $file line $line\n";
|
|
}
|
|
# we don't need to print the actual error message again so we can
|
|
# change this to "called" so that the string "$error at $file line
|
|
# $line" makes sense as "called at $file line $line".
|
|
$error = "called";
|
|
}
|
|
# this kludge circumvents die's incorrect handling of NUL
|
|
my $msg = \($mess || $error);
|
|
$$msg =~ tr/\0//d;
|
|
$$msg;
|
|
}
|
|
|
|
|
|
# shortmess() 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 longmess() to
|
|
# generate that. In verbose mode shortmess() calls longmess() so
|
|
# you always get a stack trace
|
|
|
|
sub shortmess { # Short-circuit &longmess if called via multiple packages
|
|
goto &longmess if $Verbose;
|
|
my $error = join '', @_;
|
|
my ($prevpack) = caller(1);
|
|
my $extra = $CarpLevel;
|
|
my $i = 2;
|
|
my ($pack,$file,$line);
|
|
# when reporting an error, we want to report it from the context of the
|
|
# calling package. So what is the calling package? Within a module,
|
|
# there may be many calls between methods and perhaps between sub-classes
|
|
# and super-classes, but the user isn't interested in what happens
|
|
# inside the package. We start by building a hash array which keeps
|
|
# track of all the packages to which the calling package belongs. We
|
|
# do this by examining its @ISA variable. Any call from a base class
|
|
# method (one of our caller's @ISA packages) can be ignored
|
|
my %isa = ($prevpack,1);
|
|
|
|
# merge all the caller's @ISA packages into %isa.
|
|
@isa{@{"${prevpack}::ISA"}} = ()
|
|
if(defined @{"${prevpack}::ISA"});
|
|
|
|
# now we crawl up the calling stack and look at all the packages in
|
|
# there. For each package, we look to see if it has an @ISA and then
|
|
# we see if our caller features in that list. That would imply that
|
|
# our caller is a derived class of that package and its calls can also
|
|
# be ignored
|
|
while (($pack,$file,$line) = caller($i++)) {
|
|
if(defined @{$pack . "::ISA"}) {
|
|
my @i = @{$pack . "::ISA"};
|
|
my %i;
|
|
@i{@i} = ();
|
|
# merge any relevant packages into %isa
|
|
@isa{@i,$pack} = ()
|
|
if(exists $i{$prevpack} || exists $isa{$pack});
|
|
}
|
|
|
|
# and here's where we do the ignoring... if the package in
|
|
# question is one of our caller's base or derived packages then
|
|
# we can ignore it (skip it) and go onto the next (but note that
|
|
# the continue { } block below gets called every time)
|
|
next
|
|
if(exists $isa{$pack});
|
|
|
|
# Hey! We've found a package that isn't one of our caller's
|
|
# clan....but wait, $extra refers to the number of 'extra' levels
|
|
# we should skip up. If $extra > 0 then this is a false alarm.
|
|
# We must merge the package into the %isa hash (so we can ignore it
|
|
# if it pops up again), decrement $extra, and continue.
|
|
if ($extra-- > 0) {
|
|
%isa = ($pack,1);
|
|
@isa{@{$pack . "::ISA"}} = ()
|
|
if(defined @{$pack . "::ISA"});
|
|
}
|
|
else {
|
|
# OK! We've got a candidate package. Time to construct the
|
|
# relevant error message and return it. die() doesn't like
|
|
# to be given NUL characters (which $msg may contain) so we
|
|
# remove them first.
|
|
(my $msg = "$error at $file line $line\n") =~ tr/\0//d;
|
|
return $msg;
|
|
}
|
|
}
|
|
continue {
|
|
$prevpack = $pack;
|
|
}
|
|
|
|
# uh-oh! It looks like we crawled all the way up the stack and
|
|
# never found a candidate package. Oh well, let's call longmess
|
|
# to generate a full stack trace. We use the magical form of 'goto'
|
|
# so that this shortmess() function doesn't appear on the stack
|
|
# to further confuse longmess() about it's calling package.
|
|
goto &longmess;
|
|
}
|
|
|
|
|
|
# the following four functions call longmess() or shortmess() 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.
|
|
|
|
sub croak { die shortmess @_ }
|
|
sub confess { die longmess @_ }
|
|
sub carp { warn shortmess @_ }
|
|
sub cluck { warn longmess @_ }
|
|
|
|
1;
|