FILE: C:\Program Files (x86)\Plesk\perl\lib\diagnostics.pm

--
package diagnostics;

=head1 NAME

diagnostics, splain - produce verbose warning diagnostics

=head1 SYNOPSIS

Using the C pragma:

    use diagnostics;
    use diagnostics -verbose;

    diagnostics->enable;
    diagnostics->disable;

Using the C standalone filter program:

    perl program 2>diag.out
    splain [-v] [-p] diag.out

Using diagnostics to get stack traces from a misbehaving script:

    perl -Mdiagnostics=-traceonly my_script.pl

=head1 DESCRIPTION

=head2 The C Pragma

This module extends the terse diagnostics normally emitted by both the
perl compiler and the perl interpreter (from running perl with a -w 
switch or C), augmenting them with the more
explicative and endearing descriptions found in L.  Like the
other pragmata, it affects the compilation phase of your program rather
than merely the execution phase.

To use in your program as a pragma, merely invoke

    use diagnostics;

at the start (or near the start) of your program.  (Note 
that this I enable perl's B<-w> flag.)  Your whole
compilation will then be subject(ed :-) to the enhanced diagnostics.
These still go out B.

Due to the interaction between runtime and compiletime issues,
and because it's probably not a very good idea anyway,
you may not use C to turn them off at compiletime.
However, you may control their behaviour at runtime using the 
C and C methods to turn them off and on respectively.

The B<-verbose> flag first prints out the L introduction before
any other diagnostics.  The $diagnostics::PRETTY variable can generate nicer
escape sequences for pagers.

Warnings dispatched from perl itself (or more accurately, those that match
descriptions found in L) are only displayed once (no duplicate
descriptions).  User code generated warnings a la warn() are unaffected,
allowing duplicate user messages to be displayed.

This module also adds a stack trace to the error message when perl dies.
This is useful for pinpointing what
caused the death.  The B<-traceonly> (or
just B<-t>) flag turns off the explanations of warning messages leaving just
the stack traces.  So if your script is dieing, run it again with

  perl -Mdiagnostics=-traceonly my_bad_script

to see the call stack at the time of death.  By supplying the B<-warntrace>
(or just B<-w>) flag, any warnings emitted will also come with a stack
trace.

=head2 The I Program

Another program, I is actually nothing
more than a link to the (executable) F module, as well as
a link to the F documentation.  The B<-v> flag is like
the C directive.
The B<-p> flag is like the
$diagnostics::PRETTY variable.  Since you're post-processing with 
I, there's no sense in being able to enable() or disable() processing.

Output from I is directed to B, unlike the pragma.

=head1 EXAMPLES

The following file is certain to trigger a few errors at both
runtime and compiletime:

    use diagnostics;
    print NOWHERE "nothing\n";
    print STDERR "\n\tThis message should be unadorned.\n";
    warn "\tThis is a user warning";
    print "\nDIAGNOSTIC TESTER: Please enter a  here: ";
    my $a, $b = scalar ;
    print "\n";
    print $x/$y;

If you prefer to run your program first and look at its problem
afterwards, do this:

    perl -w test.pl 2>test.out
    ./splain < test.out

Note that this is not in general possible in shells of more dubious heritage, 
as the theoretical 

    (perl -w test.pl >/dev/tty) >& test.out
    ./splain < test.out

Because you just moved the existing B to somewhere else.

If you don't want to modify your source code, but still have on-the-fly
warnings, do this:

    exec 3>&1; perl -w test.pl 2>&1 1>&3 3>&- | splain 1>&2 3>&- 

Nifty, eh?

If you want to control warnings on the fly, do something like this.
Make sure you do the C first, or you won't be able to get
at the enable() or disable() methods.

    use diagnostics; # checks entire compilation phase 
	print "\ntime for 1st bogus diags: SQUAWKINGS\n";
	print BOGUS1 'nada';
	print "done with 1st bogus\n";

    diagnostics->disable; # only turns off runtime warnings
	print "\ntime for 2nd bogus: (squelched)\n";
	print BOGUS2 'nada';
	print "done with 2nd bogus\n";

    diagnostics->enable; # turns back on runtime warnings
	print "\ntime for 3rd bogus: SQUAWKINGS\n";
	print BOGUS3 'nada';
	print "done with 3rd bogus\n";

    diagnostics->disable;
	print "\ntime for 4th bogus: (squelched)\n";
	print BOGUS4 'nada';
	print "done with 4th bogus\n";

=head1 INTERNALS

Diagnostic messages derive from the F file when available at
runtime.  Otherwise, they may be embedded in the file itself when the
splain package is built.   See the F for details.

If an extant $SIG{__WARN__} handler is discovered, it will continue
to be honored, but only after the diagnostics::splainthis() function 
(the module's $SIG{__WARN__} interceptor) has had its way with your
warnings.

There is a $diagnostics::DEBUG variable you may set if you're desperately
curious what sorts of things are being intercepted.

    BEGIN { $diagnostics::DEBUG = 1 } 


=head1 BUGS

Not being able to say "no diagnostics" is annoying, but may not be
insurmountable.

The C<-pretty> directive is called too late to affect matters.
You have to do this instead, and I you load the module.

    BEGIN { $diagnostics::PRETTY = 1 } 

I could start up faster by delaying compilation until it should be
needed, but this gets a "panic: top_level" when using the pragma form
in Perl 5.001e.

While it's true that this documentation is somewhat subserious, if you use
a program named I, you should expect a bit of whimsy.

=head1 AUTHOR

Tom Christiansen >, 25 June 1995.

=cut

use strict;
use 5.009001;
use Carp;
$Carp::Internal{__PACKAGE__.""}++;

our $VERSION = '1.40';
our $DEBUG;
our $VERBOSE;
our $PRETTY;
our $TRACEONLY = 0;
our $WARNTRACE = 0;

use Config;
use Text::Tabs 'expand';
my $privlib = $Config{privlibexp};
if ($^O eq 'VMS') {
    require VMS::Filespec;
    $privlib = VMS::Filespec::unixify($privlib);
}
my @trypod = (
	   "$privlib/pod/perldiag.pod",
	   "$privlib/pods/perldiag.pod",
	  );
# handy for development testing of new warnings etc
unshift @trypod, "./pod/perldiag.pod" if -e "pod/perldiag.pod";
(my $PODFILE) = ((grep { -e } @trypod), $trypod[$#trypod])[0];

$DEBUG ||= 0;

local $| = 1;
local $_;
local $.;

my $standalone;
my(%HTML_2_Troff, %HTML_2_Latin_1, %HTML_2_ASCII_7);

CONFIG: {
    our $opt_p = our $opt_d = our $opt_v = our $opt_f = '';

    unless (caller) {
	$standalone++;
	require Getopt::Std;
	Getopt::Std::getopts('pdvf:')
	    or die "Usage: $0 [-v] [-p] [-f splainpod]";
	$PODFILE = $opt_f if $opt_f;
	$DEBUG = 2 if $opt_d;
	$VERBOSE = $opt_v;
	$PRETTY = $opt_p;
    }

    if (open(POD_DIAG, '<', $PODFILE)) {
	warn "Happy happy podfile from real $PODFILE\n" if $DEBUG;
	last CONFIG;
    } 

    if (caller) {
	INCPATH: {
	    for my $file ( (map { "$_/".__PACKAGE__.".pm" } @INC), $0) {
		warn "Checking $file\n" if $DEBUG;
		if (open(POD_DIAG, '<', $file)) {
		    while () {
			next unless
			    /^__END__\s*# wish diag dbase were more accessible/;
			print STDERR "podfile is $file\n" if $DEBUG;
			last INCPATH;
		    }
		}
	    } 
	}
    } else { 
	print STDERR "podfile is \n" if $DEBUG;
	*POD_DIAG = *main::DATA;
    }
}
if (eof(POD_DIAG)) { 
    die "couldn't find diagnostic data in $PODFILE @INC $0";
}


%HTML_2_Troff = (
    'amp'	=>	'&',	#   ampersand
    'lt'	=>	'<',	#   left chevron, less-than
    'gt'	=>	'>',	#   right chevron, greater-than
    'quot'	=>	'"',	#   double quote
    'sol'	=>	'/',	#   forward slash / solidus
    'verbar'    =>	'|',	#   vertical bar

    "Aacute"	=>	"A\\*'",	#   capital A, acute accent
    # etc

);

%HTML_2_Latin_1 = (
    'amp'	=>	'&',	#   ampersand
    'lt'	=>	'<',	#   left chevron, less-than
    'gt'	=>	'>',	#   right chevron, greater-than
    'quot'	=>	'"',	#   double quote
    'sol'	=>	'/',	#   Forward slash / solidus
    'verbar'    =>	'|',	#   vertical bar

    #                           #   capital A, acute accent
    "Aacute"	=>	chr utf8::unicode_to_native(0xC1)

    # etc
);

%HTML_2_ASCII_7 = (
    'amp'	=>	'&',	#   ampersand
    'lt'	=>	'<',	#   left chevron, less-than
    'gt'	=>	'>',	#   right chevron, greater-than
    'quot'	=>	'"',	#   double quote
    'sol'	=>	'/',	#   Forward slash / solidus
    'verbar'    =>	'|',	#   vertical bar

    "Aacute"	=>	"A"	#   capital A, acute accent
    # etc
);

our %HTML_Escapes;
*HTML_Escapes = do {
    if ($standalone) {
	$PRETTY ? \%HTML_2_Latin_1 : \%HTML_2_ASCII_7; 
    } else {
	\%HTML_2_Latin_1; 
    }
}; 

*THITHER = $standalone ? *STDOUT : *STDERR;

my %transfmt = (); 
my $transmo = <) {

	sub _split_pod_link {
	    $_[0] =~ m'(?:([^|]*)\|)?([^/]*)(?:/("?)(.*)\3)?'s;
	    ($1,$2,$4);
	}

	unescape();
	if ($PRETTY) {
	    sub noop   { return $_[0] }  # spensive for a noop
	    sub bold   { my $str =$_[0];  $str =~ s/(.)/$1\b$1/g; return $str; } 
	    sub italic { my $str = $_[0]; $str =~ s/(.)/_\b$1/g;  return $str; } 
	    s/C<<< (.*?) >>>|C<< (.*?) >>|[BC]<(.*?)>/bold($+)/ges;
	    s/[IF]<(.*?)>/italic($1)/ges;
	    s/L<(.*?)>/
	       my($text,$page,$sect) = _split_pod_link($1);
	       defined $text
	        ? $text
	        : defined $sect
	           ? italic($sect) . ' in ' . italic($page)
	           : italic($page)
	     /ges;
	     s/S<(.*?)>/
               $1
             /ges;
	} else {
	    s/C<<< (.*?) >>>|C<< (.*?) >>|[BC]<(.*?)>/$+/gs;
	    s/[IF]<(.*?)>/$1/gs;
	    s/L<(.*?)>/
	       my($text,$page,$sect) = _split_pod_link($1);
	       defined $text
	        ? $text
	        : defined $sect
	           ? qq '"$sect" in $page'
	           : $page
	     /ges;
	    s/S<(.*?)>/
               $1
             /ges;
	} 
	unless (/^=/) {
	    if (defined $header) { 
		if ( $header eq 'DESCRIPTION' && 
		    (   /Optional warnings are enabled/ 
		     || /Some of these messages are generic./
		    ) )
		{
		    next;
		}
		$_ = expand $_;
		s/^/    /gm;
		$msg{$header} .= $_;
		for my $h(@headers) { $msg{$h} .= $_ }
		++$seen_body;
	 	undef $for_item;	
	    }
	    next;
	} 

	# If we have not come across the body of the description yet, then
	# the previous header needs to share the same description.
	if ($seen_body) {
	    @headers = ();
	}
	else {
	    push @headers, $header if defined $header;
	}

	if ( ! s/=item (.*?)\s*\z//s || $over_level != 1) {

	    if ( s/=head1\sDESCRIPTION//) {
		$msg{$header = 'DESCRIPTION'} = '';
		undef $for_item;
	    }
	    elsif( s/^=for\s+diagnostics\s*\n(.*?)\s*\z// ) {
		$for_item = $1;
	    }
	    elsif( /^=over\b/ ) {
                $over_level++;
            }
	    elsif( /^=back\b/ ) { # Stop processing body here
                $over_level--;
                if ($over_level == 0) {
                    undef $header;
                    undef $for_item;
                    $seen_body = 0;
                    next;
                }
	    }
	    next;
	}

	if( $for_item ) { $header = $for_item; undef $for_item } 
	else {
	    $header = $1;

	    $header =~ s/\n/ /gs; # Allow multi-line headers
	}

	# strip formatting directives from =item line
	$header =~ s/[A-Z]<(.*?)>/$1/g;

	# Since we strip "(\.\s*)\n" when we search a warning, strip it here as well
	$header =~ s/(\.\s*)?$//;

        my @toks = split( /(%l?[dxX]|%[ucp]|%(?:\.\d+)?[fs])/, $header );
	if (@toks > 1) {
            my $conlen = 0;
            for my $i (0..$#toks){
                if( $i % 2 ){
                    if(      $toks[$i] eq '%c' ){
                        $toks[$i] = '.';
                    } elsif( $toks[$i] =~ /^%(?:d|u)$/ ){
                        $toks[$i] = '\d+';
                    } elsif( $toks[$i] =~ '^%(?:s|.*f)$' ){
                        $toks[$i] = $i == $#toks ? '.*' : '.*?';
                    } elsif( $toks[$i] =~ '%.(\d+)s' ){
                        $toks[$i] = ".{$1}";
                    } elsif( $toks[$i] =~ '^%l*([pxX])$' ){
                        $toks[$i] = $1 eq 'X' ? '[\dA-F]+' : '[\da-f]+';
                    }
                } elsif( length( $toks[$i] ) ){
                    $toks[$i] = quotemeta $toks[$i];
                    $conlen += length( $toks[$i] );
                }
            }  
            my $lhs = join( '', @toks );
            $lhs =~ s/(\\\s)+/\\s+/g; # Replace lit space with multi-space match
	    $transfmt{$header}{pat} =
              "    s^\\s*$lhs\\s*\Q$header\Es\n\t&& return 1;\n";
            $transfmt{$header}{len} = $conlen;
	} else {
            my $lhs = "\Q$header\E";
            $lhs =~ s/(\\\s)+/\\s+/g; # Replace lit space with multi-space match
            $transfmt{$header}{pat} =
	      "    s^\\s*$lhs\\s*\Q$header\E\n\t && return 1;\n";
            $transfmt{$header}{len} = length( $header );
	} 

	print STDERR __PACKAGE__.": Duplicate entry: \"$header\"\n"
	    if $msg{$header};

	$msg{$header} = '';
	$seen_body = 0;
    } 


    close POD_DIAG unless *main::DATA eq *POD_DIAG;

    die "No diagnostics?" unless %msg;

    # Apply patterns in order of decreasing sum of lengths of fixed parts
    # Seems the best way of hitting the right one.
    for my $hdr ( sort { $transfmt{$b}{len} <=> $transfmt{$a}{len} }
                  keys %transfmt ){
        $transmo .= $transfmt{$hdr}{pat};
    }
    $transmo .= "    return 0;\n}\n";
    print STDERR $transmo if $DEBUG;
    eval $transmo;
    die $@ if $@;
}

if ($standalone) {
    if (!@ARGV and -t STDIN) { print STDERR "$0: Reading from STDIN\n" } 
    while (defined (my $error = <>)) {
	splainthis($error) || print THITHER $error;
    } 
    exit;
} 

my $olddie;
my $oldwarn;

sub import {
    shift;
    $^W = 1; # yup, clobbered the global variable; 
	     # tough, if you want diags, you want diags.
    return if defined $SIG{__WARN__} && ($SIG{__WARN__} eq \&warn_trap);

    for (@_) {

	/^-d(ebug)?$/ 	   	&& do {
				    $DEBUG++;
				    next;
				   };

	/^-v(erbose)?$/ 	&& do {
				    $VERBOSE++;
				    next;
				   };

	/^-p(retty)?$/ 		&& do {
				    print STDERR "$0: I'm afraid it's too late for prettiness.\n";
				    $PRETTY++;
				    next;
			       };
	# matches trace and traceonly for legacy doc mixup reasons
	/^-t(race(only)?)?$/	&& do {
				    $TRACEONLY++;
				    next;
			       };
	/^-w(arntrace)?$/ 	&& do {
				    $WARNTRACE++;
				    next;
			       };

	warn "Unknown flag: $_";
    } 

    $oldwarn = $SIG{__WARN__};
    $olddie = $SIG{__DIE__};
    $SIG{__WARN__} = \&warn_trap;
    $SIG{__DIE__} = \&death_trap;
} 

sub enable { &import }

sub disable {
    shift;
    return unless $SIG{__WARN__} eq \&warn_trap;
    $SIG{__WARN__} = $oldwarn || '';
    $SIG{__DIE__} = $olddie || '';
} 

sub warn_trap {
    my $warning = $_[0];
    if (caller eq __PACKAGE__ or !splainthis($warning)) {
	if ($WARNTRACE) {
	    print STDERR Carp::longmess($warning);
	} else {
	    print STDERR $warning;
	}
    } 
    goto &$oldwarn if defined $oldwarn and $oldwarn and $oldwarn ne \&warn_trap;
};

sub death_trap {
    my $exception = $_[0];

    # See if we are coming from anywhere within an eval. If so we don't
    # want to explain the exception because it's going to get caught.
    my $in_eval = 0;
    my $i = 0;
    while (my $caller = (caller($i++))[3]) {
      if ($caller eq '(eval)') {
	$in_eval = 1;
	last;
      }
    }

    splainthis($exception) unless $in_eval;
    if (caller eq __PACKAGE__) {
	print STDERR "INTERNAL EXCEPTION: $exception";
    } 
    &$olddie if defined $olddie and $olddie and $olddie ne \&death_trap;

    return if $in_eval;

    # We don't want to unset these if we're coming from an eval because
    # then we've turned off diagnostics.

    # Switch off our die/warn handlers so we don't wind up in our own
    # traps.
    $SIG{__DIE__} = $SIG{__WARN__} = '';

    $exception =~ s/\n(?=.)/\n\t/gas;

    die Carp::longmess("__diagnostics__")
	  =~ s/^__diagnostics__.*?line \d+\.?\n/
		  "Uncaught exception from user code:\n\t$exception"
	      /re;
	# up we go; where we stop, nobody knows, but i think we die now
	# but i'm deeply afraid of the &$olddie guy reraising and us getting
	# into an indirect recursion loop
};

my %exact_duplicate;
my %old_diag;
my $count;
my $wantspace;
sub splainthis {
  return 0 if $TRACEONLY;
  for (my $tmp = shift) {
    local $\;
    local $!;
    ### &finish_compilation unless %msg;
    s/(\.\s*)?\n+$//;
    my $orig = $_;
    # return unless defined;

    # get rid of the where-are-we-in-input part
    s/, <.*?> (?:line|chunk).*$//;

    # Discard 1st " at  line " and all text beyond
    # but be aware of messages containing " at this-or-that"
    my $real = 0;
    my @secs = split( / at / );
    return unless @secs;
    $_ = $secs[0];
    for my $i ( 1..$#secs ){
        if( $secs[$i] =~ /.+? (?:line|chunk) \d+/ ){
            $real = 1;
            last;
        } else {
            $_ .= ' at ' . $secs[$i];
	}
    }

    # remove parenthesis occurring at the end of some messages 
    s/^\((.*)\)$/$1/;

    if ($exact_duplicate{$orig}++) {
	return &transmo;
    } else {
	return 0 unless &transmo;
    }

    my $short = shorten($orig);
    if ($old_diag{$_}) {
	autodescribe();
	print THITHER "$short (#$old_diag{$_})\n";
	$wantspace = 1;
    } elsif (!$msg{$_} && $orig =~ /\n./s) {
	# A multiline message, like "Attempt to reload /
	# Compilation failed"
	my $found;
	for (split /^/, $orig) {
	    splainthis($_) and $found = 1;
	}
	return $found;
    } else {
	autodescribe();
	$old_diag{$_} = ++$count;
	print THITHER "\n" if $wantspace;
	$wantspace = 0;
	print THITHER "$short (#$old_diag{$_})\n";
	if ($msg{$_}) {
	    print THITHER $msg{$_};
	} else {
	    if (0 and $standalone) { 
		print THITHER "    **** Error #$old_diag{$_} ",
			($real ? "is" : "appears to be"),
			" an unknown diagnostic message.\n\n";
	    }
	    return 0;
	} 
    }
    return 1;
  }
} 

sub autodescribe {
    if ($VERBOSE and not $count) {
	print THITHER &{$PRETTY ? \&bold : \&noop}("DESCRIPTION OF DIAGNOSTICS"),
		"\n$msg{DESCRIPTION}\n";
    } 
} 

sub unescape { 
    s {
            E<  
            ( [A-Za-z]+ )       
            >   
    } { 
         do {   
             exists $HTML_Escapes{$1}
                ? do { $HTML_Escapes{$1} }
                : do {
                    warn "Unknown escape: E<$1> in $_";
                    "E<$1>";
                } 
         } 
    }egx;
}

sub shorten {
    my $line = $_[0];
    if (length($line) > 79 and index($line, "\n") == -1) {
	my $space_place = rindex($line, ' ', 79);
	if ($space_place != -1) {
	    substr($line, $space_place, 1) = "\n\t";
	} 
    } 
    return $line;
} 


1 unless $standalone;  # or it'll complain about itself
__END__ # wish diag dbase were more accessible

--