lib/perl5/5.8.8/Carp/Heavy.pm

   1 # Carp::Heavy uses some variables in common with Carp.
   2 package Carp;
   3
   4 =head1 NAME
   5
   6 Carp::Heavy - heavy machinery, no user serviceable parts inside
   7
   8 =cut
   9
  10 # use strict; # not yet
  11
  12 # On one line so MakeMaker will see it.
  13 use Carp;  our $VERSION = $Carp::VERSION;
  14
  15 our ($CarpLevel, $MaxArgNums, $MaxEvalLen, $MaxArgLen, $Verbose);
  16
  17 sub caller_info {
  18   my $i = shift(@_) + 1;
  19   package DB;
  20   my %call_info;
  21   @call_info{
  22     qw(pack file line sub has_args wantarray evaltext is_require)
  23   } = caller($i);
  24
  25   unless (defined $call_info{pack}) {
  26     return ();
  27   }
  28
  29   my $sub_name = Carp::get_subname(\%call_info);
  30   if ($call_info{has_args}) {
  31     my @args = map {Carp::format_arg($_)} @DB::args;
  32     if ($MaxArgNums and @args > $MaxArgNums) { # More than we want to show?
  33       $#args = $MaxArgNums;
  34       push @args, '...';
  35     }
  36     # Push the args onto the subroutine
  37     $sub_name .= '(' . join (', ', @args) . ')';
  38   }
  39   $call_info{sub_name} = $sub_name;
  40   return wantarray() ? %call_info : \%call_info;
  41 }
  42
  43 # Transform an argument to a function into a string.
  44 sub format_arg {
  45   my $arg = shift;
  46   if (ref($arg)) {
  47       $arg = defined($overload::VERSION) ? overload::StrVal($arg) : "$arg";
  48   }elsif (not defined($arg)) {
  49     $arg = 'undef';
  50   }
  51   $arg =~ s/'/\\'/g;
  52   $arg = str_len_trim($arg, $MaxArgLen);
  53
  54   # Quote it?
  55   $arg = "'$arg'" unless $arg =~ /^-?[\d.]+\z/;
  56
  57   # The following handling of "control chars" is direct from
  58   # the original code - it is broken on Unicode though.
  59   # Suggestions?
  60   utf8::is_utf8($arg)
  61     or $arg =~ s/([[:cntrl:]]|[[:^ascii:]])/sprintf("\\x{%x}",ord($1))/eg;
  62   return $arg;
  63 }
  64
  65 # Takes an inheritance cache and a package and returns
  66 # an anon hash of known inheritances and anon array of
  67 # inheritances which consequences have not been figured
  68 # for.
  69 sub get_status {
  70     my $cache = shift;
  71     my $pkg = shift;
  72     $cache->{$pkg} ||= [{$pkg => $pkg}, [trusts_directly($pkg)]];
  73     return @{$cache->{$pkg}};
  74 }
  75
  76 # Takes the info from caller() and figures out the name of
  77 # the sub/require/eval
  78 sub get_subname {
  79   my $info = shift;
  80   if (defined($info->{evaltext})) {
  81     my $eval = $info->{evaltext};
  82     if ($info->{is_require}) {
  83       return "require $eval";
  84     }
  85     else {
  86       $eval =~ s/([\\\'])/\\$1/g;
  87       return "eval '" . str_len_trim($eval, $MaxEvalLen) . "'";
  88     }
  89   }
  90
  91   return ($info->{sub} eq '(eval)') ? 'eval {...}' : $info->{sub};
  92 }
  93
  94 # Figures out what call (from the point of view of the caller)
  95 # the long error backtrace should start at.
  96 sub long_error_loc {
  97   my $i;
  98   my $lvl = $CarpLevel;
  99   {
 100     my $pkg = caller(++$i);
 101     unless(defined($pkg)) {
 102       # This *shouldn't* happen.
 103       if (%Internal) {
 104         local %Internal;
 105         $i = long_error_loc();
 106         last;
 107       }
 108       else {
 109         # OK, now I am irritated.
 110         return 2;
 111       }
 112     }
 113     redo if $CarpInternal{$pkg};
 114     redo unless 0 > --$lvl;
 115     redo if $Internal{$pkg};
 116   }
 117   return $i - 1;
 118 }
 119
 120
 121 sub longmess_heavy {
 122   return @_ if ref($_[0]); # don't break references as exceptions
 123   my $i = long_error_loc();
 124   return ret_backtrace($i, @_);
 125 }
 126
 127 # Returns a full stack backtrace starting from where it is
 128 # told.
 129 sub ret_backtrace {
 130   my ($i, @error) = @_;
 131   my $mess;
 132   my $err = join '', @error;
 133   $i++;
 134
 135   my $tid_msg = '';
 136   if (defined &Thread::tid) {
 137     my $tid = Thread->self->tid;
 138     $tid_msg = " thread $tid" if $tid;
 139   }
 140
 141   my %i = caller_info($i);
 142   $mess = "$err at $i{file} line $i{line}$tid_msg\n";
 143
 144   while (my %i = caller_info(++$i)) {
 145       $mess .= "\t$i{sub_name} called at $i{file} line $i{line}$tid_msg\n";
 146   }
 147
 148   return $mess;
 149 }
 150
 151 sub ret_summary {
 152   my ($i, @error) = @_;
 153   my $err = join '', @error;
 154   $i++;
 155
 156   my $tid_msg = '';
 157   if (defined &Thread::tid) {
 158     my $tid = Thread->self->tid;
 159     $tid_msg = " thread $tid" if $tid;
 160   }
 161
 162   my %i = caller_info($i);
 163   return "$err at $i{file} line $i{line}$tid_msg\n";
 164 }
 165
 166
 167 sub short_error_loc {
 168   my $cache;
 169   my $i = 1;
 170   my $lvl = $CarpLevel;
 171   {
 172     my $called = caller($i++);
 173     my $caller = caller($i);
 174     return 0 unless defined($caller); # What happened?
 175     redo if $Internal{$caller};
 176     redo if $CarpInternal{$called};
 177     redo if trusts($called, $caller, $cache);
 178     redo if trusts($caller, $called, $cache);
 179     redo unless 0 > --$lvl;
 180   }
 181   return $i - 1;
 182 }
 183
 184 sub shortmess_heavy {
 185   return longmess_heavy(@_) if $Verbose;
 186   return @_ if ref($_[0]); # don't break references as exceptions
 187   my $i = short_error_loc();
 188   if ($i) {
 189     ret_summary($i, @_);
 190   }
 191   else {
 192     longmess_heavy(@_);
 193   }
 194 }
 195
 196 # If a string is too long, trims it with ...
 197 sub str_len_trim {
 198   my $str = shift;
 199   my $max = shift || 0;
 200   if (2 < $max and $max < length($str)) {
 201     substr($str, $max - 3) = '...';
 202   }
 203   return $str;
 204 }
 205
 206 # Takes two packages and an optional cache.  Says whether the
 207 # first inherits from the second.
 208 #
 209 # Recursive versions of this have to work to avoid certain
 210 # possible endless loops, and when following long chains of
 211 # inheritance are less efficient.
 212 sub trusts {
 213     my $child = shift;
 214     my $parent = shift;
 215     my $cache = shift || {};
 216     my ($known, $partial) = get_status($cache, $child);
 217     # Figure out consequences until we have an answer
 218     while (@$partial and not exists $known->{$parent}) {
 219         my $anc = shift @$partial;
 220         next if exists $known->{$anc};
 221         $known->{$anc}++;
 222         my ($anc_knows, $anc_partial) = get_status($cache, $anc);
 223         my @found = keys %$anc_knows;
 224         @$known{@found} = ();
 225         push @$partial, @$anc_partial;
 226     }
 227     return exists $known->{$parent};
 228 }
 229
 230 # Takes a package and gives a list of those trusted directly
 231 sub trusts_directly {
 232     my $class = shift;
 233     no strict 'refs';
 234     no warnings 'once';
 235     return @{"$class\::CARP_NOT"}
 236       ? @{"$class\::CARP_NOT"}
 237       : @{"$class\::ISA"};
 238 }
 239
 240 1;
 241