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1 | package Fatal; |
2 | |
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3 | use 5.008; # 5.8.x needed for autodie |
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4 | use Carp; |
5 | use strict; |
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6 | use warnings; |
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7 | |
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8 | use constant LEXICAL_TAG => q{:lexical}; |
9 | use constant VOID_TAG => q{:void}; |
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10 | |
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11 | use constant ERROR_NOARGS => 'Cannot use lexical %s with no arguments'; |
12 | use constant ERROR_VOID_LEX => VOID_TAG.' cannot be used with lexical scope'; |
13 | use constant ERROR_LEX_FIRST => LEXICAL_TAG.' must be used as first argument'; |
14 | use constant ERROR_NO_LEX => "no %s can only start with ".LEXICAL_TAG; |
15 | use constant ERROR_BADNAME => "Bad subroutine name for %s: %s"; |
16 | use constant ERROR_NOTSUB => "%s is not a Perl subroutine"; |
17 | use constant ERROR_NOT_BUILT => "%s is neither a builtin, nor a Perl subroutine"; |
18 | use constant ERROR_CANT_OVERRIDE => "Cannot make the non-overridable builtin %s fatal"; |
19 | |
20 | use constant ERROR_NO_IPC_SYS_SIMPLE => "IPC::System::Simple required for Fatalised/autodying system()"; |
21 | |
22 | use constant ERROR_IPC_SYS_SIMPLE_OLD => "IPC::System::Simple version %f required for Fatalised/autodying system(). We only have version %f"; |
23 | |
24 | use constant ERROR_AUTODIE_CONFLICT => q{"no autodie '%s'" is not allowed while "use Fatal '%s'" is in effect}; |
25 | |
26 | use constant ERROR_FATAL_CONFLICT => q{"use Fatal '%s'" is not allowed while "no autodie '%s'" is in effect}; |
27 | |
28 | # Older versions of IPC::System::Simple don't support all the |
29 | # features we need. |
30 | |
31 | use constant MIN_IPC_SYS_SIMPLE_VER => 0.12; |
32 | |
33 | # All the Fatal/autodie modules share the same version number. |
34 | our $VERSION = '1.997'; |
35 | |
36 | our $Debug ||= 0; |
37 | |
38 | # EWOULDBLOCK values for systems that don't supply their own. |
39 | # Even though this is defined with our, that's to help our |
40 | # test code. Please don't rely upon this variable existing in |
41 | # the future. |
42 | |
43 | our %_EWOULDBLOCK = ( |
44 | MSWin32 => 33, |
45 | ); |
46 | |
47 | # We have some tags that can be passed in for use with import. |
48 | # These are all assumed to be CORE:: |
49 | |
50 | my %TAGS = ( |
51 | ':io' => [qw(:dbm :file :filesys :ipc :socket |
52 | read seek sysread syswrite sysseek )], |
53 | ':dbm' => [qw(dbmopen dbmclose)], |
54 | ':file' => [qw(open close flock sysopen fcntl fileno binmode |
55 | ioctl truncate)], |
56 | ':filesys' => [qw(opendir closedir chdir link unlink rename mkdir |
57 | symlink rmdir readlink umask)], |
58 | ':ipc' => [qw(:msg :semaphore :shm pipe)], |
59 | ':msg' => [qw(msgctl msgget msgrcv msgsnd)], |
60 | ':threads' => [qw(fork)], |
61 | ':semaphore'=>[qw(semctl semget semop)], |
62 | ':shm' => [qw(shmctl shmget shmread)], |
63 | ':system' => [qw(system exec)], |
64 | |
65 | # Can we use qw(getpeername getsockname)? What do they do on failure? |
66 | # XXX - Can socket return false? |
67 | ':socket' => [qw(accept bind connect getsockopt listen recv send |
68 | setsockopt shutdown socketpair)], |
69 | |
70 | # Our defaults don't include system(), because it depends upon |
71 | # an optional module, and it breaks the exotic form. |
72 | # |
73 | # This *may* change in the future. I'd love IPC::System::Simple |
74 | # to be a dependency rather than a recommendation, and hence for |
75 | # system() to be autodying by default. |
76 | |
77 | ':default' => [qw(:io :threads)], |
78 | |
79 | # Version specific tags. These allow someone to specify |
80 | # use autodie qw(:1.994) and know exactly what they'll get. |
81 | |
82 | ':1.994' => [qw(:default)], |
83 | ':1.995' => [qw(:default)], |
84 | ':1.996' => [qw(:default)], |
85 | ':1.997' => [qw(:default)], |
86 | |
87 | ); |
88 | |
89 | $TAGS{':all'} = [ keys %TAGS ]; |
90 | |
91 | # This hash contains subroutines for which we should |
92 | # subroutine() // die() rather than subroutine() || die() |
93 | |
94 | my %Use_defined_or; |
95 | |
96 | # CORE::open returns undef on failure. It can legitimately return |
97 | # 0 on success, eg: open(my $fh, '-|') || exec(...); |
98 | |
99 | @Use_defined_or{qw( |
100 | CORE::fork |
101 | CORE::recv |
102 | CORE::send |
103 | CORE::open |
104 | CORE::fileno |
105 | CORE::read |
106 | CORE::readlink |
107 | CORE::sysread |
108 | CORE::syswrite |
109 | CORE::sysseek |
110 | CORE::umask |
111 | )} = (); |
112 | |
113 | # Cached_fatalised_sub caches the various versions of our |
114 | # fatalised subs as they're produced. This means we don't |
115 | # have to build our own replacement of CORE::open and friends |
116 | # for every single package that wants to use them. |
117 | |
118 | my %Cached_fatalised_sub = (); |
119 | |
120 | # Every time we're called with package scope, we record the subroutine |
121 | # (including package or CORE::) in %Package_Fatal. This allows us |
122 | # to detect illegal combinations of autodie and Fatal, and makes sure |
123 | # we don't accidently make a Fatal function autodying (which isn't |
124 | # very useful). |
125 | |
126 | my %Package_Fatal = (); |
127 | |
128 | # The first time we're called with a user-sub, we cache it here. |
129 | # In the case of a "no autodie ..." we put back the cached copy. |
130 | |
131 | my %Original_user_sub = (); |
132 | |
133 | # We use our package in a few hash-keys. Having it in a scalar is |
134 | # convenient. The "guard $PACKAGE" string is used as a key when |
135 | # setting up lexical guards. |
136 | |
137 | my $PACKAGE = __PACKAGE__; |
138 | my $PACKAGE_GUARD = "guard $PACKAGE"; |
139 | my $NO_PACKAGE = "no $PACKAGE"; # Used to detect 'no autodie' |
140 | |
141 | # Here's where all the magic happens when someone write 'use Fatal' |
142 | # or 'use autodie'. |
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143 | |
144 | sub import { |
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145 | my $class = shift(@_); |
146 | my $void = 0; |
147 | my $lexical = 0; |
148 | |
149 | my ($pkg, $filename) = caller(); |
150 | |
151 | @_ or return; # 'use Fatal' is a no-op. |
152 | |
153 | # If we see the :lexical flag, then _all_ arguments are |
154 | # changed lexically |
155 | |
156 | if ($_[0] eq LEXICAL_TAG) { |
157 | $lexical = 1; |
158 | shift @_; |
159 | |
160 | # If we see no arguments and :lexical, we assume they |
161 | # wanted ':default'. |
162 | |
163 | if (@_ == 0) { |
164 | push(@_, ':default'); |
165 | } |
166 | |
167 | # Don't allow :lexical with :void, it's needlessly confusing. |
168 | if ( grep { $_ eq VOID_TAG } @_ ) { |
169 | croak(ERROR_VOID_LEX); |
170 | } |
171 | } |
172 | |
173 | if ( grep { $_ eq LEXICAL_TAG } @_ ) { |
174 | # If we see the lexical tag as the non-first argument, complain. |
175 | croak(ERROR_LEX_FIRST); |
176 | } |
177 | |
178 | my @fatalise_these = @_; |
179 | |
180 | # Thiese subs will get unloaded at the end of lexical scope. |
181 | my %unload_later; |
182 | |
183 | # This hash helps us track if we've alredy done work. |
184 | my %done_this; |
185 | |
186 | # NB: we're using while/shift rather than foreach, since |
187 | # we'll be modifying the array as we walk through it. |
188 | |
189 | while (my $func = shift @fatalise_these) { |
190 | |
191 | if ($func eq VOID_TAG) { |
192 | |
193 | # When we see :void, set the void flag. |
194 | $void = 1; |
195 | |
196 | } elsif (exists $TAGS{$func}) { |
197 | |
198 | # When it's a tag, expand it. |
199 | push(@fatalise_these, @{ $TAGS{$func} }); |
200 | |
201 | } else { |
202 | |
203 | # Otherwise, fatalise it. |
204 | |
205 | # If we've already made something fatal this call, |
206 | # then don't do it twice. |
207 | |
208 | next if $done_this{$func}; |
209 | |
210 | # We're going to make a subroutine fatalistic. |
211 | # However if we're being invoked with 'use Fatal qw(x)' |
212 | # and we've already been called with 'no autodie qw(x)' |
213 | # in the same scope, we consider this to be an error. |
214 | # Mixing Fatal and autodie effects was considered to be |
215 | # needlessly confusing on p5p. |
216 | |
217 | my $sub = $func; |
218 | $sub = "${pkg}::$sub" unless $sub =~ /::/; |
219 | |
220 | # If we're being called as Fatal, and we've previously |
221 | # had a 'no X' in scope for the subroutine, then complain |
222 | # bitterly. |
223 | |
224 | if (! $lexical and $^H{$NO_PACKAGE}{$sub}) { |
225 | croak(sprintf(ERROR_FATAL_CONFLICT, $func, $func)); |
226 | } |
227 | |
228 | # We're not being used in a confusing way, so make |
229 | # the sub fatal. Note that _make_fatal returns the |
230 | # old (original) version of the sub, or undef for |
231 | # built-ins. |
232 | |
233 | my $sub_ref = $class->_make_fatal( |
234 | $func, $pkg, $void, $lexical, $filename |
235 | ); |
236 | |
237 | $done_this{$func}++; |
238 | |
239 | $Original_user_sub{$sub} ||= $sub_ref; |
240 | |
241 | # If we're making lexical changes, we need to arrange |
242 | # for them to be cleaned at the end of our scope, so |
243 | # record them here. |
244 | |
245 | $unload_later{$func} = $sub_ref if $lexical; |
246 | } |
247 | } |
248 | |
249 | if ($lexical) { |
250 | |
251 | # Dark magic to have autodie work under 5.8 |
252 | # Copied from namespace::clean, that copied it from |
253 | # autobox, that found it on an ancient scroll written |
254 | # in blood. |
255 | |
256 | # This magic bit causes %^H to be lexically scoped. |
257 | |
258 | $^H |= 0x020000; |
259 | |
260 | # Our package guard gets invoked when we leave our lexical |
261 | # scope. |
262 | |
263 | push(@ { $^H{$PACKAGE_GUARD} }, autodie::Scope::Guard->new(sub { |
264 | $class->_install_subs($pkg, \%unload_later); |
265 | })); |
266 | |
267 | } |
268 | |
269 | return; |
270 | |
271 | } |
272 | |
273 | # The code here is originally lifted from namespace::clean, |
274 | # by Robert "phaylon" Sedlacek. |
275 | # |
276 | # It's been redesigned after feedback from ikegami on perlmonks. |
277 | # See http://perlmonks.org/?node_id=693338 . Ikegami rocks. |
278 | # |
279 | # Given a package, and hash of (subname => subref) pairs, |
280 | # we install the given subroutines into the package. If |
281 | # a subref is undef, the subroutine is removed. Otherwise |
282 | # it replaces any existing subs which were already there. |
283 | |
284 | sub _install_subs { |
285 | my ($class, $pkg, $subs_to_reinstate) = @_; |
286 | |
287 | my $pkg_sym = "${pkg}::"; |
288 | |
289 | while(my ($sub_name, $sub_ref) = each %$subs_to_reinstate) { |
290 | |
291 | my $full_path = $pkg_sym.$sub_name; |
292 | |
293 | # Copy symbols across to temp area. |
294 | |
295 | no strict 'refs'; ## no critic |
296 | |
297 | local *__tmp = *{ $full_path }; |
298 | |
299 | # Nuke the old glob. |
300 | { no strict; delete $pkg_sym->{$sub_name}; } ## no critic |
301 | |
302 | # Copy innocent bystanders back. |
303 | |
304 | foreach my $slot (qw( SCALAR ARRAY HASH IO FORMAT ) ) { |
305 | next unless defined *__tmp{ $slot }; |
306 | *{ $full_path } = *__tmp{ $slot }; |
307 | } |
308 | |
309 | # Put back the old sub (if there was one). |
310 | |
311 | if ($sub_ref) { |
312 | |
313 | no strict; ## no critic |
314 | *{ $pkg_sym . $sub_name } = $sub_ref; |
315 | } |
316 | } |
317 | |
318 | return; |
319 | } |
320 | |
321 | sub unimport { |
322 | my $class = shift; |
323 | |
324 | # Calling "no Fatal" must start with ":lexical" |
325 | if ($_[0] ne LEXICAL_TAG) { |
326 | croak(sprintf(ERROR_NO_LEX,$class)); |
327 | } |
328 | |
329 | shift @_; # Remove :lexical |
330 | |
331 | my $pkg = (caller)[0]; |
332 | |
333 | # If we've been called with arguments, then the developer |
334 | # has explicitly stated 'no autodie qw(blah)', |
335 | # in which case, we disable Fatalistic behaviour for 'blah'. |
336 | |
337 | my @unimport_these = @_ ? @_ : ':all'; |
338 | |
339 | while (my $symbol = shift @unimport_these) { |
340 | |
341 | if ($symbol =~ /^:/) { |
342 | |
343 | # Looks like a tag! Expand it! |
344 | push(@unimport_these, @{ $TAGS{$symbol} }); |
345 | |
346 | next; |
347 | } |
348 | |
349 | my $sub = $symbol; |
350 | $sub = "${pkg}::$sub" unless $sub =~ /::/; |
351 | |
352 | # If 'blah' was already enabled with Fatal (which has package |
353 | # scope) then, this is considered an error. |
354 | |
355 | if (exists $Package_Fatal{$sub}) { |
356 | croak(sprintf(ERROR_AUTODIE_CONFLICT,$symbol,$symbol)); |
357 | } |
358 | |
359 | # Record 'no autodie qw($sub)' as being in effect. |
360 | # This is to catch conflicting semantics elsewhere |
361 | # (eg, mixing Fatal with no autodie) |
362 | |
363 | $^H{$NO_PACKAGE}{$sub} = 1; |
364 | |
365 | if (my $original_sub = $Original_user_sub{$sub}) { |
366 | # Hey, we've got an original one of these, put it back. |
367 | $class->_install_subs($pkg, { $symbol => $original_sub }); |
368 | next; |
369 | } |
370 | |
371 | # We don't have an original copy of the sub, on the assumption |
372 | # it's core (or doesn't exist), we'll just nuke it. |
373 | |
374 | $class->_install_subs($pkg,{ $symbol => undef }); |
375 | |
376 | } |
377 | |
378 | return; |
379 | |
380 | } |
381 | |
382 | # TODO - This is rather terribly inefficient right now. |
383 | |
384 | # NB: Perl::Critic's dump-autodie-tag-contents depends upon this |
385 | # continuing to work. |
386 | |
387 | { |
388 | my %tag_cache; |
389 | |
390 | sub _expand_tag { |
391 | my ($class, $tag) = @_; |
392 | |
393 | if (my $cached = $tag_cache{$tag}) { |
394 | return $cached; |
395 | } |
396 | |
397 | if (not exists $TAGS{$tag}) { |
398 | croak "Invalid exception class $tag"; |
399 | } |
400 | |
401 | my @to_process = @{$TAGS{$tag}}; |
402 | |
403 | my @taglist = (); |
404 | |
405 | while (my $item = shift @to_process) { |
406 | if ($item =~ /^:/) { |
407 | push(@to_process, @{$TAGS{$item}} ); |
408 | } else { |
409 | push(@taglist, "CORE::$item"); |
410 | } |
411 | } |
412 | |
413 | $tag_cache{$tag} = \@taglist; |
414 | |
415 | return \@taglist; |
416 | |
417 | } |
418 | |
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419 | } |
420 | |
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421 | # This code is from the original Fatal. It scares me. |
422 | |
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423 | sub fill_protos { |
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424 | my $proto = shift; |
425 | my ($n, $isref, @out, @out1, $seen_semi) = -1; |
426 | while ($proto =~ /\S/) { |
427 | $n++; |
428 | push(@out1,[$n,@out]) if $seen_semi; |
429 | push(@out, $1 . "{\$_[$n]}"), next if $proto =~ s/^\s*\\([\@%\$\&])//; |
430 | push(@out, "\$_[$n]"), next if $proto =~ s/^\s*([_*\$&])//; |
431 | push(@out, "\@_[$n..\$#_]"), last if $proto =~ s/^\s*(;\s*)?\@//; |
432 | $seen_semi = 1, $n--, next if $proto =~ s/^\s*;//; # XXXX ???? |
433 | die "Internal error: Unknown prototype letters: \"$proto\""; |
434 | } |
435 | push(@out1,[$n+1,@out]); |
436 | return @out1; |
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437 | } |
438 | |
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439 | # This generates the code that will become our fatalised subroutine. |
440 | |
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441 | sub write_invocation { |
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442 | my ($class, $core, $call, $name, $void, $lexical, $sub, @argvs) = @_; |
443 | |
444 | if (@argvs == 1) { # No optional arguments |
445 | |
446 | my @argv = @{$argvs[0]}; |
447 | shift @argv; |
448 | |
449 | return $class->one_invocation($core,$call,$name,$void,$sub,! $lexical,@argv); |
450 | |
451 | } else { |
452 | my $else = "\t"; |
453 | my (@out, @argv, $n); |
454 | while (@argvs) { |
455 | @argv = @{shift @argvs}; |
456 | $n = shift @argv; |
457 | |
458 | push @out, "${else}if (\@_ == $n) {\n"; |
459 | $else = "\t} els"; |
460 | |
461 | push @out, $class->one_invocation($core,$call,$name,$void,$sub,! $lexical,@argv); |
462 | } |
463 | push @out, q[ |
464 | } |
465 | die "Internal error: $name(\@_): Do not expect to get ", scalar \@_, " arguments"; |
466 | ]; |
467 | |
468 | return join '', @out; |
469 | } |
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470 | } |
471 | |
472 | sub one_invocation { |
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473 | my ($class, $core, $call, $name, $void, $sub, $back_compat, @argv) = @_; |
474 | |
475 | # If someone is calling us directly (a child class perhaps?) then |
476 | # they could try to mix void without enabling backwards |
477 | # compatibility. We just don't support this at all, so we gripe |
478 | # about it rather than doing something unwise. |
479 | |
480 | if ($void and not $back_compat) { |
481 | Carp::confess("Internal error: :void mode not supported with $class"); |
482 | } |
483 | |
484 | # @argv only contains the results of the in-built prototype |
485 | # function, and is therefore safe to interpolate in the |
486 | # code generators below. |
487 | |
488 | # TODO - The following clobbers context, but that's what the |
489 | # old Fatal did. Do we care? |
490 | |
491 | if ($back_compat) { |
492 | |
493 | # TODO - Use Fatal qw(system) is not yet supported. It should be! |
494 | |
495 | if ($call eq 'CORE::system') { |
496 | return q{ |
497 | croak("UNIMPLEMENTED: use Fatal qw(system) not yet supported."); |
498 | }; |
499 | } |
500 | |
501 | local $" = ', '; |
502 | |
503 | if ($void) { |
504 | return qq/return (defined wantarray)?$call(@argv): |
505 | $call(@argv) || croak "Can't $name(\@_)/ . |
506 | ($core ? ': $!' : ', \$! is \"$!\"') . '"' |
507 | } else { |
508 | return qq{return $call(@argv) || croak "Can't $name(\@_)} . |
509 | ($core ? ': $!' : ', \$! is \"$!\"') . '"'; |
510 | } |
511 | } |
512 | |
513 | # The name of our original function is: |
514 | # $call if the function is CORE |
515 | # $sub if our function is non-CORE |
516 | |
517 | # The reason for this is that $call is what we're actualling |
518 | # calling. For our core functions, this is always |
519 | # CORE::something. However for user-defined subs, we're about to |
520 | # replace whatever it is that we're calling; as such, we actually |
521 | # calling a subroutine ref. |
522 | |
523 | # Unfortunately, none of this tells us the *ultimate* name. |
524 | # For example, if I export 'copy' from File::Copy, I'd like my |
525 | # ultimate name to be File::Copy::copy. |
526 | # |
527 | # TODO - Is there any way to find the ultimate name of a sub, as |
528 | # described above? |
529 | |
530 | my $true_sub_name = $core ? $call : $sub; |
531 | |
532 | if ($call eq 'CORE::system') { |
533 | |
534 | # Leverage IPC::System::Simple if we're making an autodying |
535 | # system. |
536 | |
537 | local $" = ", "; |
538 | |
539 | # We need to stash $@ into $E, rather than using |
540 | # local $@ for the whole sub. If we don't then |
541 | # any exceptions from internal errors in autodie/Fatal |
542 | # will mysteriously disappear before propogating |
543 | # upwards. |
544 | |
545 | return qq{ |
546 | my \$retval; |
547 | my \$E; |
548 | |
549 | |
550 | { |
551 | local \$@; |
552 | |
553 | eval { |
554 | \$retval = IPC::System::Simple::system(@argv); |
555 | }; |
556 | |
557 | \$E = \$@; |
558 | } |
559 | |
560 | if (\$E) { |
561 | |
562 | # XXX - TODO - This can't be overridden in child |
563 | # classes! |
564 | |
565 | die autodie::exception::system->new( |
566 | function => q{CORE::system}, args => [ @argv ], |
567 | message => "\$E", errno => \$!, |
568 | ); |
569 | } |
570 | |
571 | return \$retval; |
572 | }; |
573 | |
574 | } |
575 | |
576 | # Should we be testing to see if our result is defined, or |
577 | # just true? |
578 | my $use_defined_or = exists ( $Use_defined_or{$call} ); |
579 | |
580 | local $" = ', '; |
581 | |
582 | # If we're going to throw an exception, here's the code to use. |
583 | my $die = qq{ |
584 | die $class->throw( |
585 | function => q{$true_sub_name}, args => [ @argv ], |
586 | pragma => q{$class}, errno => \$!, |
587 | ) |
588 | }; |
589 | |
590 | if ($call eq 'CORE::flock') { |
591 | |
592 | # flock needs special treatment. When it fails with |
593 | # LOCK_UN and EWOULDBLOCK, then it's not really fatal, it just |
594 | # means we couldn't get the lock right now. |
595 | |
596 | require POSIX; # For POSIX::EWOULDBLOCK |
597 | |
598 | local $@; # Don't blat anyone else's $@. |
599 | |
600 | # Ensure that our vendor supports EWOULDBLOCK. If they |
601 | # don't (eg, Windows), then we use known values for its |
602 | # equivalent on other systems. |
603 | |
604 | my $EWOULDBLOCK = eval { POSIX::EWOULDBLOCK(); } |
605 | || $_EWOULDBLOCK{$^O} |
606 | || _autocroak("Internal error - can't overload flock - EWOULDBLOCK not defined on this system."); |
607 | |
608 | require Fcntl; # For Fcntl::LOCK_NB |
609 | |
610 | return qq{ |
611 | |
612 | # Try to flock. If successful, return it immediately. |
613 | |
614 | my \$retval = $call(@argv); |
615 | return \$retval if \$retval; |
616 | |
617 | # If we failed, but we're using LOCK_NB and |
618 | # returned EWOULDBLOCK, it's not a real error. |
619 | |
620 | if (\$_[1] & Fcntl::LOCK_NB() and \$! == $EWOULDBLOCK ) { |
621 | return \$retval; |
622 | } |
623 | |
624 | # Otherwise, we failed. Die noisily. |
625 | |
626 | $die; |
627 | |
628 | }; |
629 | } |
630 | |
631 | # AFAIK everything that can be given an unopned filehandle |
632 | # will fail if it tries to use it, so we don't really need |
633 | # the 'unopened' warning class here. Especially since they |
634 | # then report the wrong line number. |
635 | |
636 | return qq{ |
637 | no warnings qw(unopened); |
638 | |
639 | if (wantarray) { |
640 | my \@results = $call(@argv); |
641 | # If we got back nothing, or we got back a single |
642 | # undef, we die. |
643 | if (! \@results or (\@results == 1 and ! defined \$results[0])) { |
644 | $die; |
645 | }; |
646 | return \@results; |
647 | } |
648 | |
649 | # Otherwise, we're in scalar context. |
650 | # We're never in a void context, since we have to look |
651 | # at the result. |
652 | |
653 | my \$result = $call(@argv); |
654 | |
655 | } . ( $use_defined_or ? qq{ |
656 | |
657 | $die if not defined \$result; |
658 | |
659 | return \$result; |
660 | |
661 | } : qq{ |
662 | |
663 | return \$result || $die; |
664 | |
665 | } ) ; |
666 | |
e92e55da |
667 | } |
668 | |
0b09a93a |
669 | # This returns the old copy of the sub, so we can |
670 | # put it back at end of scope. |
671 | |
672 | # TODO : Check to make sure prototypes are restored correctly. |
673 | |
674 | # TODO: Taking a huge list of arguments is awful. Rewriting to |
675 | # take a hash would be lovely. |
676 | |
e92e55da |
677 | sub _make_fatal { |
0b09a93a |
678 | my($class, $sub, $pkg, $void, $lexical, $filename) = @_; |
e92e55da |
679 | my($name, $code, $sref, $real_proto, $proto, $core, $call); |
680 | my $ini = $sub; |
681 | |
682 | $sub = "${pkg}::$sub" unless $sub =~ /::/; |
0b09a93a |
683 | |
684 | # Figure if we're using lexical or package semantics and |
685 | # twiddle the appropriate bits. |
686 | |
687 | if (not $lexical) { |
688 | $Package_Fatal{$sub} = 1; |
689 | } |
690 | |
691 | # TODO - We *should* be able to do skipping, since we know when |
692 | # we've lexicalised / unlexicalised a subroutine. |
693 | |
e92e55da |
694 | $name = $sub; |
695 | $name =~ s/.*::// or $name =~ s/^&//; |
0b09a93a |
696 | |
697 | warn "# _make_fatal: sub=$sub pkg=$pkg name=$name void=$void\n" if $Debug; |
698 | croak(sprintf(ERROR_BADNAME, $class, $name)) unless $name =~ /^\w+$/; |
699 | |
700 | if (defined(&$sub)) { # user subroutine |
701 | |
702 | # This could be something that we've fatalised that |
703 | # was in core. |
704 | |
705 | local $@; # Don't clobber anyone else's $@ |
706 | |
707 | if ( $Package_Fatal{$sub} and eval { prototype "CORE::$name" } ) { |
708 | |
709 | # Something we previously made Fatal that was core. |
710 | # This is safe to replace with an autodying to core |
711 | # version. |
712 | |
713 | $core = 1; |
714 | $call = "CORE::$name"; |
715 | $proto = prototype $call; |
716 | |
717 | # We return our $sref from this subroutine later |
718 | # on, indicating this subroutine should be placed |
719 | # back when we're finished. |
720 | |
721 | $sref = \&$sub; |
722 | |
723 | } else { |
724 | |
725 | # A regular user sub, or a user sub wrapping a |
726 | # core sub. |
727 | |
728 | $sref = \&$sub; |
729 | $proto = prototype $sref; |
730 | $call = '&$sref'; |
731 | |
732 | } |
733 | |
910ad8dd |
734 | } elsif ($sub eq $ini && $sub !~ /^CORE::GLOBAL::/) { |
0b09a93a |
735 | # Stray user subroutine |
736 | croak(sprintf(ERROR_NOTSUB,$sub)); |
737 | |
738 | } elsif ($name eq 'system') { |
739 | |
740 | # If we're fatalising system, then we need to load |
741 | # helper code. |
742 | |
743 | eval { |
744 | require IPC::System::Simple; # Only load it if we need it. |
745 | require autodie::exception::system; |
746 | }; |
747 | |
748 | if ($@) { croak ERROR_NO_IPC_SYS_SIMPLE; } |
749 | |
750 | # Make sure we're using a recent version of ISS that actually |
751 | # support fatalised system. |
752 | if ($IPC::System::Simple::VERSION < MIN_IPC_SYS_SIMPLE_VER) { |
753 | croak sprintf( |
754 | ERROR_IPC_SYS_SIMPLE_OLD, MIN_IPC_SYS_SIMPLE_VER, |
755 | $IPC::System::Simple::VERSION |
756 | ); |
757 | } |
758 | |
759 | $call = 'CORE::system'; |
760 | $name = 'system'; |
761 | |
762 | } elsif ($name eq 'exec') { |
763 | # Exec doesn't have a prototype. We don't care. This |
764 | # breaks the exotic form with lexical scope, and gives |
765 | # the regular form a "do or die" beaviour as expected. |
766 | |
767 | $call = 'CORE::exec'; |
768 | $name = 'exec'; |
769 | $core = 1; |
770 | |
771 | } else { # CORE subroutine |
e92e55da |
772 | $proto = eval { prototype "CORE::$name" }; |
0b09a93a |
773 | croak(sprintf(ERROR_NOT_BUILT,$name)) if $@; |
774 | croak(sprintf(ERROR_CANT_OVERRIDE,$name)) if not defined $proto; |
775 | $core = 1; |
776 | $call = "CORE::$name"; |
e92e55da |
777 | } |
0b09a93a |
778 | |
e92e55da |
779 | if (defined $proto) { |
0b09a93a |
780 | $real_proto = " ($proto)"; |
e92e55da |
781 | } else { |
0b09a93a |
782 | $real_proto = ''; |
783 | $proto = '@'; |
784 | } |
785 | |
786 | my $true_name = $core ? $call : $sub; |
787 | |
788 | # TODO: This caching works, but I don't like using $void and |
789 | # $lexical as keys. In particular, I suspect our code may end up |
790 | # wrapping already wrapped code when autodie and Fatal are used |
791 | # together. |
792 | |
793 | # NB: We must use '$sub' (the name plus package) and not |
794 | # just '$name' (the short name) here. Failing to do so |
795 | # results code that's in the wrong package, and hence has |
796 | # access to the wrong package filehandles. |
797 | |
798 | if (my $subref = $Cached_fatalised_sub{$class}{$sub}{$void}{$lexical}) { |
799 | $class->_install_subs($pkg, { $name => $subref }); |
800 | return $sref; |
e92e55da |
801 | } |
0b09a93a |
802 | |
803 | $code = qq[ |
804 | sub$real_proto { |
805 | local(\$", \$!) = (', ', 0); # TODO - Why do we do this? |
806 | ]; |
807 | |
808 | # Don't have perl whine if exec fails, since we'll be handling |
809 | # the exception now. |
810 | $code .= "no warnings qw(exec);\n" if $call eq "CORE::exec"; |
811 | |
e92e55da |
812 | my @protos = fill_protos($proto); |
0b09a93a |
813 | $code .= $class->write_invocation($core, $call, $name, $void, $lexical, $sub, @protos); |
e92e55da |
814 | $code .= "}\n"; |
0b09a93a |
815 | warn $code if $Debug; |
816 | |
817 | # I thought that changing package was a monumental waste of |
818 | # time for CORE subs, since they'll always be the same. However |
819 | # that's not the case, since they may refer to package-based |
820 | # filehandles (eg, with open). |
821 | # |
822 | # There is potential to more aggressively cache core subs |
823 | # that we know will never want to interact with package variables |
824 | # and filehandles. |
825 | |
2ba6ecf4 |
826 | { |
0b09a93a |
827 | local $@; |
828 | no strict 'refs'; ## no critic # to avoid: Can't use string (...) as a symbol ref ... |
829 | $code = eval("package $pkg; use Carp; $code"); ## no critic |
830 | if (not $code) { |
831 | |
832 | # For some reason, using a die, croak, or confess in here |
833 | # results in the error being completely surpressed. As such, |
834 | # we need to do our own reporting. |
835 | # |
836 | # TODO: Fix the above. |
837 | |
838 | _autocroak("Internal error in autodie/Fatal processing $true_name: $@"); |
839 | |
840 | } |
841 | } |
842 | |
843 | # Now we need to wrap our fatalised sub inside an itty bitty |
844 | # closure, which can detect if we've leaked into another file. |
845 | # Luckily, we only need to do this for lexical (autodie) |
846 | # subs. Fatal subs can leak all they want, it's considered |
847 | # a "feature" (or at least backwards compatible). |
848 | |
849 | # TODO: Cache our leak guards! |
850 | |
851 | # TODO: This is pretty hairy code. A lot more tests would |
852 | # be really nice for this. |
853 | |
854 | my $leak_guard; |
855 | |
856 | if ($lexical) { |
857 | |
858 | $leak_guard = qq< |
859 | package $pkg; |
860 | |
861 | sub$real_proto { |
862 | |
863 | # If we're called from the correct file, then use the |
864 | # autodying code. |
865 | goto &\$code if ((caller)[1] eq \$filename); |
866 | |
867 | # Oh bother, we've leaked into another file. Call the |
868 | # original code. Note that \$sref may actually be a |
869 | # reference to a Fatalised version of a core built-in. |
870 | # That's okay, because Fatal *always* leaks between files. |
871 | |
872 | goto &\$sref if \$sref; |
873 | >; |
874 | |
875 | |
876 | # If we're here, it must have been a core subroutine called. |
877 | # Warning: The following code may disturb some viewers. |
878 | |
879 | # TODO: It should be possible to combine this with |
880 | # write_invocation(). |
881 | |
882 | foreach my $proto (@protos) { |
883 | local $" = ", "; # So @args is formatted correctly. |
884 | my ($count, @args) = @$proto; |
885 | $leak_guard .= qq< |
886 | if (\@_ == $count) { |
887 | return $call(@args); |
888 | } |
889 | >; |
890 | } |
891 | |
892 | $leak_guard .= qq< croak "Internal error in Fatal/autodie. Leak-guard failure"; } >; |
893 | |
894 | # warn "$leak_guard\n"; |
895 | |
896 | local $@; |
897 | |
898 | $leak_guard = eval $leak_guard; ## no critic |
899 | |
900 | die "Internal error in $class: Leak-guard installation failure: $@" if $@; |
901 | } |
902 | |
903 | $class->_install_subs($pkg, { $name => $leak_guard || $code }); |
904 | |
905 | $Cached_fatalised_sub{$class}{$sub}{$void}{$lexical} = $leak_guard || $code; |
906 | |
907 | return $sref; |
908 | |
909 | } |
910 | |
911 | # This subroutine exists primarily so that child classes can override |
912 | # it to point to their own exception class. Doing this is significantly |
913 | # less complex than overriding throw() |
914 | |
915 | sub exception_class { return "autodie::exception" }; |
916 | |
917 | { |
918 | my %exception_class_for; |
919 | my %class_loaded; |
920 | |
921 | sub throw { |
922 | my ($class, @args) = @_; |
923 | |
924 | # Find our exception class if we need it. |
925 | my $exception_class = |
926 | $exception_class_for{$class} ||= $class->exception_class; |
927 | |
928 | if (not $class_loaded{$exception_class}) { |
929 | if ($exception_class =~ /[^\w:']/) { |
930 | confess "Bad exception class '$exception_class'.\nThe '$class->exception_class' method wants to use $exception_class\nfor exceptions, but it contains characters which are not word-characters or colons."; |
931 | } |
932 | |
933 | # Alas, Perl does turn barewords into modules unless they're |
934 | # actually barewords. As such, we're left doing a string eval |
935 | # to make sure we load our file correctly. |
936 | |
937 | my $E; |
938 | |
939 | { |
940 | local $@; # We can't clobber $@, it's wrong! |
941 | eval "require $exception_class"; ## no critic |
942 | $E = $@; # Save $E despite ending our local. |
943 | } |
944 | |
945 | # We need quotes around $@ to make sure it's stringified |
946 | # while still in scope. Without them, we run the risk of |
947 | # $@ having been cleared by us exiting the local() block. |
948 | |
949 | confess "Failed to load '$exception_class'.\nThis may be a typo in the '$class->exception_class' method,\nor the '$exception_class' module may not exist.\n\n $E" if $E; |
950 | |
951 | $class_loaded{$exception_class}++; |
952 | |
953 | } |
954 | |
955 | return $exception_class->new(@args); |
2ba6ecf4 |
956 | } |
e92e55da |
957 | } |
958 | |
0b09a93a |
959 | # For some reason, dying while replacing our subs doesn't |
960 | # kill our calling program. It simply stops the loading of |
961 | # autodie and keeps going with everything else. The _autocroak |
962 | # sub allows us to die with a vegence. It should *only* ever be |
963 | # used for serious internal errors, since the results of it can't |
964 | # be captured. |
965 | |
966 | sub _autocroak { |
967 | warn Carp::longmess(@_); |
968 | exit(255); # Ugh! |
969 | } |
970 | |
971 | package autodie::Scope::Guard; |
972 | |
973 | # This code schedules the cleanup of subroutines at the end of |
974 | # scope. It's directly inspired by chocolateboy's excellent |
975 | # Scope::Guard module. |
976 | |
977 | sub new { |
978 | my ($class, $handler) = @_; |
979 | |
980 | return bless $handler, $class; |
981 | } |
982 | |
983 | sub DESTROY { |
984 | my ($self) = @_; |
985 | |
986 | $self->(); |
987 | } |
988 | |
e92e55da |
989 | 1; |
990 | |
991 | __END__ |
992 | |
993 | =head1 NAME |
994 | |
0b09a93a |
995 | Fatal - Replace functions with equivalents which succeed or die |
e92e55da |
996 | |
997 | =head1 SYNOPSIS |
998 | |
999 | use Fatal qw(open close); |
1000 | |
0b09a93a |
1001 | open(my $fh, "<", $filename); # No need to check errors! |
1002 | |
1003 | use File::Copy qw(move); |
1004 | use Fatal qw(move); |
1005 | |
1006 | move($file1, $file2); # No need to check errors! |
1007 | |
e92e55da |
1008 | sub juggle { . . . } |
0b09a93a |
1009 | Fatal->import('juggle'); |
1010 | |
1011 | =head1 BEST PRACTICE |
1012 | |
1013 | B<Fatal has been obsoleted by the new L<autodie> pragma.> Please use |
1014 | L<autodie> in preference to C<Fatal>. L<autodie> supports lexical scoping, |
1015 | throws real exception objects, and provides much nicer error messages. |
1016 | |
1017 | The use of C<:void> with Fatal is discouraged. |
e92e55da |
1018 | |
1019 | =head1 DESCRIPTION |
1020 | |
0b09a93a |
1021 | C<Fatal> provides a way to conveniently replace |
1022 | functions which normally return a false value when they fail with |
1023 | equivalents which raise exceptions if they are not successful. This |
1024 | lets you use these functions without having to test their return |
1025 | values explicitly on each call. Exceptions can be caught using |
1026 | C<eval{}>. See L<perlfunc> and L<perlvar> for details. |
e92e55da |
1027 | |
1028 | The do-or-die equivalents are set up simply by calling Fatal's |
1029 | C<import> routine, passing it the names of the functions to be |
1030 | replaced. You may wrap both user-defined functions and overridable |
0b09a93a |
1031 | CORE operators (except C<exec>, C<system>, C<print>, or any other |
1032 | built-in that cannot be expressed via prototypes) in this way. |
e92e55da |
1033 | |
91c7a880 |
1034 | If the symbol C<:void> appears in the import list, then functions |
1035 | named later in that import list raise an exception only when |
1036 | these are called in void context--that is, when their return |
1037 | values are ignored. For example |
1038 | |
0b09a93a |
1039 | use Fatal qw/:void open close/; |
91c7a880 |
1040 | |
0b09a93a |
1041 | # properly checked, so no exception raised on error |
1042 | if (not open(my $fh, '<' '/bogotic') { |
1043 | warn "Can't open /bogotic: $!"; |
1044 | } |
91c7a880 |
1045 | |
0b09a93a |
1046 | # not checked, so error raises an exception |
1047 | close FH; |
1048 | |
1049 | The use of C<:void> is discouraged, as it can result in exceptions |
1050 | not being thrown if you I<accidentally> call a method without |
1051 | void context. Use L<autodie> instead if you need to be able to |
1052 | disable autodying/Fatal behaviour for a small block of code. |
1053 | |
1054 | =head1 DIAGNOSTICS |
1055 | |
1056 | =over 4 |
1057 | |
1058 | =item Bad subroutine name for Fatal: %s |
1059 | |
1060 | You've called C<Fatal> with an argument that doesn't look like |
1061 | a subroutine name, nor a switch that this version of Fatal |
1062 | understands. |
1063 | |
1064 | =item %s is not a Perl subroutine |
1065 | |
1066 | You've asked C<Fatal> to try and replace a subroutine which does not |
1067 | exist, or has not yet been defined. |
1068 | |
1069 | =item %s is neither a builtin, nor a Perl subroutine |
1070 | |
1071 | You've asked C<Fatal> to replace a subroutine, but it's not a Perl |
1072 | built-in, and C<Fatal> couldn't find it as a regular subroutine. |
1073 | It either doesn't exist or has not yet been defined. |
1074 | |
1075 | =item Cannot make the non-overridable %s fatal |
1076 | |
1077 | You've tried to use C<Fatal> on a Perl built-in that can't be |
1078 | overridden, such as C<print> or C<system>, which means that |
1079 | C<Fatal> can't help you, although some other modules might. |
1080 | See the L</"SEE ALSO"> section of this documentation. |
1081 | |
1082 | =item Internal error: %s |
1083 | |
1084 | You've found a bug in C<Fatal>. Please report it using |
1085 | the C<perlbug> command. |
1086 | |
1087 | =back |
91c7a880 |
1088 | |
a6fd7f3f |
1089 | =head1 BUGS |
1090 | |
0b09a93a |
1091 | C<Fatal> clobbers the context in which a function is called and always |
1092 | makes it a scalar context, except when the C<:void> tag is used. |
1093 | This problem does not exist in L<autodie>. |
a6fd7f3f |
1094 | |
e92e55da |
1095 | =head1 AUTHOR |
1096 | |
0b09a93a |
1097 | Original module by Lionel Cons (CERN). |
e92e55da |
1098 | |
10af26ed |
1099 | Prototype updates by Ilya Zakharevich <ilya@math.ohio-state.edu>. |
e92e55da |
1100 | |
0b09a93a |
1101 | L<autodie> support, bugfixes, extended diagnostics, C<system> |
1102 | support, and major overhauling by Paul Fenwick <pjf@perltraining.com.au> |
1103 | |
1104 | =head1 LICENSE |
1105 | |
1106 | This module is free software, you may distribute it under the |
1107 | same terms as Perl itself. |
1108 | |
1109 | =head1 SEE ALSO |
1110 | |
1111 | L<autodie> for a nicer way to use lexical Fatal. |
1112 | |
1113 | L<IPC::System::Simple> for a similar idea for calls to C<system()> |
1114 | and backticks. |
1115 | |
e92e55da |
1116 | =cut |