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[perl5.git] / lib / Carp / Heavy.pm
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b75c8c73 1# Carp::Heavy uses some variables in common with Carp.
3b5ca523 2package Carp;
ca24dfc6 3
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4=head1 NAME
5
4952958f 6Carp::Heavy - heavy machinery, no user serviceable parts inside
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7
8=cut
9
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10# On one line so MakeMaker will see it.
11use Carp; our $VERSION = $Carp::VERSION;
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12# use strict; # not yet
13
14# 'use Carp' just installs some very lightweight stubs; the first time
15# these are called, they require Carp::Heavy which installs the real
16# routines.
17
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18# The members of %Internal are packages that are internal to perl.
19# Carp will not report errors from within these packages if it
20# can. The members of %CarpInternal are internal to Perl's warning
21# system. Carp will not report errors from within these packages
22# either, and will not report calls *to* these packages for carp and
23# croak. They replace $CarpLevel, which is deprecated. The
24# $Max(EvalLen|(Arg(Len|Nums)) variables are used to specify how the eval
25# text and function arguments should be formatted when printed.
26
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27# disable these by default, so they can live w/o require Carp
28$CarpInternal{Carp}++;
29$CarpInternal{warnings}++;
30$Internal{Exporter}++;
31$Internal{'Exporter::Heavy'}++;
32
b75c8c73 33
eb2aae6f 34our ($CarpLevel, $MaxArgNums, $MaxEvalLen, $MaxArgLen, $Verbose);
ca24dfc6 35
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36# XXX longmess_real and shortmess_real should really be merged into
37# XXX {long|sort}mess_heavy at some point
38
39sub longmess_real {
40 # Icky backwards compatibility wrapper. :-(
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41 #
42 # The story is that the original implementation hard-coded the
43 # number of call levels to go back, so calls to longmess were off
44 # by one. Other code began calling longmess and expecting this
45 # behaviour, so the replacement has to emulate that behaviour.
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46 my $call_pack = caller();
47 if ($Internal{$call_pack} or $CarpInternal{$call_pack}) {
48 return longmess_heavy(@_);
49 }
50 else {
51 local $CarpLevel = $CarpLevel + 1;
52 return longmess_heavy(@_);
53 }
54};
55
56sub shortmess_real {
57 # Icky backwards compatibility wrapper. :-(
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58 local @CARP_NOT = caller();
59 shortmess_heavy(@_);
60};
61
62# replace the two hooks added by Carp
63
64# aliasing the whole glob rather than just the CV slot avoids 'redefined'
65# warnings, even in the presence of perl -W (as used by lib/warnings.t !)
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66# However it has the potential to create infinite loops, if somehow Carp
67# is forcibly reloaded, but $INC{"Carp/Heavy.pm"} remains true.
68# Hence the extra hack of deleting the previous typeglob first.
29ddba3b 69
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70delete $Carp::{shortmess_jmp};
71delete $Carp::{longmess_jmp};
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72*longmess_jmp = *longmess_real;
73*shortmess_jmp = *shortmess_real;
74
75
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76sub caller_info {
77 my $i = shift(@_) + 1;
78 package DB;
79 my %call_info;
80 @call_info{
81 qw(pack file line sub has_args wantarray evaltext is_require)
82 } = caller($i);
83
84 unless (defined $call_info{pack}) {
85 return ();
86 }
87
88 my $sub_name = Carp::get_subname(\%call_info);
89 if ($call_info{has_args}) {
a3775ca3 90 my @args = map {Carp::format_arg($_)} @DB::args;
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91 if ($MaxArgNums and @args > $MaxArgNums) { # More than we want to show?
92 $#args = $MaxArgNums;
93 push @args, '...';
94 }
95 # Push the args onto the subroutine
1798c67d 96 $sub_name .= '(' . join (', ', @args) . ')';
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97 }
98 $call_info{sub_name} = $sub_name;
99 return wantarray() ? %call_info : \%call_info;
100}
ca24dfc6 101
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102# Transform an argument to a function into a string.
103sub format_arg {
104 my $arg = shift;
8a7acfb9 105 if (ref($arg)) {
3a57e0bb 106 $arg = defined($overload::VERSION) ? overload::StrVal($arg) : "$arg";
66a4a569 107 }
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108 if (defined($arg)) {
109 $arg =~ s/'/\\'/g;
110 $arg = str_len_trim($arg, $MaxArgLen);
66a4a569 111
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112 # Quote it?
113 $arg = "'$arg'" unless $arg =~ /^-?[\d.]+\z/;
114 } else {
115 $arg = 'undef';
116 }
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117
118 # The following handling of "control chars" is direct from
e6ddefa8 119 # the original code - it is broken on Unicode though.
66a4a569 120 # Suggestions?
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121 utf8::is_utf8($arg)
122 or $arg =~ s/([[:cntrl:]]|[[:^ascii:]])/sprintf("\\x{%x}",ord($1))/eg;
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123 return $arg;
124}
ca24dfc6 125
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126# Takes an inheritance cache and a package and returns
127# an anon hash of known inheritances and anon array of
128# inheritances which consequences have not been figured
129# for.
130sub get_status {
131 my $cache = shift;
132 my $pkg = shift;
133 $cache->{$pkg} ||= [{$pkg => $pkg}, [trusts_directly($pkg)]];
134 return @{$cache->{$pkg}};
135}
ca24dfc6 136
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137# Takes the info from caller() and figures out the name of
138# the sub/require/eval
139sub get_subname {
140 my $info = shift;
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141 if (defined($info->{evaltext})) {
142 my $eval = $info->{evaltext};
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143 if ($info->{is_require}) {
144 return "require $eval";
145 }
146 else {
147 $eval =~ s/([\\\'])/\\$1/g;
976ea96e 148 return "eval '" . str_len_trim($eval, $MaxEvalLen) . "'";
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149 }
150 }
151
152 return ($info->{sub} eq '(eval)') ? 'eval {...}' : $info->{sub};
153}
154
155# Figures out what call (from the point of view of the caller)
156# the long error backtrace should start at.
157sub long_error_loc {
158 my $i;
159 my $lvl = $CarpLevel;
160 {
161 my $pkg = caller(++$i);
162 unless(defined($pkg)) {
163 # This *shouldn't* happen.
164 if (%Internal) {
165 local %Internal;
166 $i = long_error_loc();
167 last;
168 }
169 else {
170 # OK, now I am irritated.
171 return 2;
172 }
173 }
174 redo if $CarpInternal{$pkg};
175 redo unless 0 > --$lvl;
176 redo if $Internal{$pkg};
177 }
178 return $i - 1;
179}
ca24dfc6 180
3cb6de81 181
66a4a569 182sub longmess_heavy {
25f5609c 183 return @_ if ref($_[0]); # don't break references as exceptions
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184 my $i = long_error_loc();
185 return ret_backtrace($i, @_);
186}
ca24dfc6 187
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188# Returns a full stack backtrace starting from where it is
189# told.
190sub ret_backtrace {
191 my ($i, @error) = @_;
192 my $mess;
193 my $err = join '', @error;
194 $i++;
195
196 my $tid_msg = '';
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197 if (defined &threads::tid) {
198 my $tid = threads->tid;
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199 $tid_msg = " thread $tid" if $tid;
200 }
201
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202 my %i = caller_info($i);
203 $mess = "$err at $i{file} line $i{line}$tid_msg\n";
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204
205 while (my %i = caller_info(++$i)) {
206 $mess .= "\t$i{sub_name} called at $i{file} line $i{line}$tid_msg\n";
fbb63a9e 207 }
66a4a569 208
25f5609c 209 return $mess;
66a4a569 210}
3b5ca523 211
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212sub ret_summary {
213 my ($i, @error) = @_;
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214 my $err = join '', @error;
215 $i++;
3b5ca523 216
66a4a569 217 my $tid_msg = '';
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218 if (defined &threads::tid) {
219 my $tid = threads->tid;
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220 $tid_msg = " thread $tid" if $tid;
221 }
3b5ca523 222
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223 my %i = caller_info($i);
224 return "$err at $i{file} line $i{line}$tid_msg\n";
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225}
226
227
66a4a569 228sub short_error_loc {
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229 # You have to create your (hash)ref out here, rather than defaulting it
230 # inside trusts *on a lexical*, as you want it to persist across calls.
231 # (You can default it on $_[2], but that gets messy)
232 my $cache = {};
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233 my $i = 1;
234 my $lvl = $CarpLevel;
235 {
236 my $called = caller($i++);
237 my $caller = caller($i);
29ddba3b 238
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239 return 0 unless defined($caller); # What happened?
240 redo if $Internal{$caller};
d735c2ef 241 redo if $CarpInternal{$caller};
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242 redo if $CarpInternal{$called};
243 redo if trusts($called, $caller, $cache);
244 redo if trusts($caller, $called, $cache);
245 redo unless 0 > --$lvl;
246 }
247 return $i - 1;
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248}
249
29ddba3b 250
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251sub shortmess_heavy {
252 return longmess_heavy(@_) if $Verbose;
25f5609c 253 return @_ if ref($_[0]); # don't break references as exceptions
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254 my $i = short_error_loc();
255 if ($i) {
256 ret_summary($i, @_);
257 }
258 else {
259 longmess_heavy(@_);
260 }
261}
262
263# If a string is too long, trims it with ...
264sub str_len_trim {
265 my $str = shift;
266 my $max = shift || 0;
267 if (2 < $max and $max < length($str)) {
268 substr($str, $max - 3) = '...';
269 }
270 return $str;
271}
191f2cf3 272
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273# Takes two packages and an optional cache. Says whether the
274# first inherits from the second.
275#
276# Recursive versions of this have to work to avoid certain
277# possible endless loops, and when following long chains of
278# inheritance are less efficient.
279sub trusts {
280 my $child = shift;
281 my $parent = shift;
1ff09fba 282 my $cache = shift;
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283 my ($known, $partial) = get_status($cache, $child);
284 # Figure out consequences until we have an answer
285 while (@$partial and not exists $known->{$parent}) {
286 my $anc = shift @$partial;
287 next if exists $known->{$anc};
288 $known->{$anc}++;
289 my ($anc_knows, $anc_partial) = get_status($cache, $anc);
290 my @found = keys %$anc_knows;
291 @$known{@found} = ();
292 push @$partial, @$anc_partial;
3b5ca523 293 }
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294 return exists $known->{$parent};
295}
3b5ca523 296
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297# Takes a package and gives a list of those trusted directly
298sub trusts_directly {
299 my $class = shift;
a3775ca3 300 no strict 'refs';
b5777b26 301 no warnings 'once';
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302 return @{"$class\::CARP_NOT"}
303 ? @{"$class\::CARP_NOT"}
304 : @{"$class\::ISA"};
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305}
306
3071;
66a4a569 308