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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. |
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34 | our $VERSION = '1.999'; |
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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)], |
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86 | ':1.998' => [qw(:default)], |
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87 | ':1.999' => [qw(:default)], |
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88 | |
89 | ); |
90 | |
91 | $TAGS{':all'} = [ keys %TAGS ]; |
92 | |
93 | # This hash contains subroutines for which we should |
94 | # subroutine() // die() rather than subroutine() || die() |
95 | |
96 | my %Use_defined_or; |
97 | |
98 | # CORE::open returns undef on failure. It can legitimately return |
99 | # 0 on success, eg: open(my $fh, '-|') || exec(...); |
100 | |
101 | @Use_defined_or{qw( |
102 | CORE::fork |
103 | CORE::recv |
104 | CORE::send |
105 | CORE::open |
106 | CORE::fileno |
107 | CORE::read |
108 | CORE::readlink |
109 | CORE::sysread |
110 | CORE::syswrite |
111 | CORE::sysseek |
112 | CORE::umask |
113 | )} = (); |
114 | |
115 | # Cached_fatalised_sub caches the various versions of our |
116 | # fatalised subs as they're produced. This means we don't |
117 | # have to build our own replacement of CORE::open and friends |
118 | # for every single package that wants to use them. |
119 | |
120 | my %Cached_fatalised_sub = (); |
121 | |
122 | # Every time we're called with package scope, we record the subroutine |
123 | # (including package or CORE::) in %Package_Fatal. This allows us |
124 | # to detect illegal combinations of autodie and Fatal, and makes sure |
125 | # we don't accidently make a Fatal function autodying (which isn't |
126 | # very useful). |
127 | |
128 | my %Package_Fatal = (); |
129 | |
130 | # The first time we're called with a user-sub, we cache it here. |
131 | # In the case of a "no autodie ..." we put back the cached copy. |
132 | |
133 | my %Original_user_sub = (); |
134 | |
135 | # We use our package in a few hash-keys. Having it in a scalar is |
136 | # convenient. The "guard $PACKAGE" string is used as a key when |
137 | # setting up lexical guards. |
138 | |
139 | my $PACKAGE = __PACKAGE__; |
140 | my $PACKAGE_GUARD = "guard $PACKAGE"; |
141 | my $NO_PACKAGE = "no $PACKAGE"; # Used to detect 'no autodie' |
142 | |
143 | # Here's where all the magic happens when someone write 'use Fatal' |
144 | # or 'use autodie'. |
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145 | |
146 | sub import { |
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147 | my $class = shift(@_); |
148 | my $void = 0; |
149 | my $lexical = 0; |
150 | |
151 | my ($pkg, $filename) = caller(); |
152 | |
153 | @_ or return; # 'use Fatal' is a no-op. |
154 | |
155 | # If we see the :lexical flag, then _all_ arguments are |
156 | # changed lexically |
157 | |
158 | if ($_[0] eq LEXICAL_TAG) { |
159 | $lexical = 1; |
160 | shift @_; |
161 | |
162 | # If we see no arguments and :lexical, we assume they |
163 | # wanted ':default'. |
164 | |
165 | if (@_ == 0) { |
166 | push(@_, ':default'); |
167 | } |
168 | |
169 | # Don't allow :lexical with :void, it's needlessly confusing. |
170 | if ( grep { $_ eq VOID_TAG } @_ ) { |
171 | croak(ERROR_VOID_LEX); |
172 | } |
173 | } |
174 | |
175 | if ( grep { $_ eq LEXICAL_TAG } @_ ) { |
176 | # If we see the lexical tag as the non-first argument, complain. |
177 | croak(ERROR_LEX_FIRST); |
178 | } |
179 | |
180 | my @fatalise_these = @_; |
181 | |
182 | # Thiese subs will get unloaded at the end of lexical scope. |
183 | my %unload_later; |
184 | |
185 | # This hash helps us track if we've alredy done work. |
186 | my %done_this; |
187 | |
188 | # NB: we're using while/shift rather than foreach, since |
189 | # we'll be modifying the array as we walk through it. |
190 | |
191 | while (my $func = shift @fatalise_these) { |
192 | |
193 | if ($func eq VOID_TAG) { |
194 | |
195 | # When we see :void, set the void flag. |
196 | $void = 1; |
197 | |
198 | } elsif (exists $TAGS{$func}) { |
199 | |
200 | # When it's a tag, expand it. |
201 | push(@fatalise_these, @{ $TAGS{$func} }); |
202 | |
203 | } else { |
204 | |
205 | # Otherwise, fatalise it. |
206 | |
207 | # If we've already made something fatal this call, |
208 | # then don't do it twice. |
209 | |
210 | next if $done_this{$func}; |
211 | |
212 | # We're going to make a subroutine fatalistic. |
213 | # However if we're being invoked with 'use Fatal qw(x)' |
214 | # and we've already been called with 'no autodie qw(x)' |
215 | # in the same scope, we consider this to be an error. |
216 | # Mixing Fatal and autodie effects was considered to be |
217 | # needlessly confusing on p5p. |
218 | |
219 | my $sub = $func; |
220 | $sub = "${pkg}::$sub" unless $sub =~ /::/; |
221 | |
222 | # If we're being called as Fatal, and we've previously |
223 | # had a 'no X' in scope for the subroutine, then complain |
224 | # bitterly. |
225 | |
226 | if (! $lexical and $^H{$NO_PACKAGE}{$sub}) { |
227 | croak(sprintf(ERROR_FATAL_CONFLICT, $func, $func)); |
228 | } |
229 | |
230 | # We're not being used in a confusing way, so make |
231 | # the sub fatal. Note that _make_fatal returns the |
232 | # old (original) version of the sub, or undef for |
233 | # built-ins. |
234 | |
235 | my $sub_ref = $class->_make_fatal( |
236 | $func, $pkg, $void, $lexical, $filename |
237 | ); |
238 | |
239 | $done_this{$func}++; |
240 | |
241 | $Original_user_sub{$sub} ||= $sub_ref; |
242 | |
243 | # If we're making lexical changes, we need to arrange |
244 | # for them to be cleaned at the end of our scope, so |
245 | # record them here. |
246 | |
247 | $unload_later{$func} = $sub_ref if $lexical; |
248 | } |
249 | } |
250 | |
251 | if ($lexical) { |
252 | |
253 | # Dark magic to have autodie work under 5.8 |
254 | # Copied from namespace::clean, that copied it from |
255 | # autobox, that found it on an ancient scroll written |
256 | # in blood. |
257 | |
258 | # This magic bit causes %^H to be lexically scoped. |
259 | |
260 | $^H |= 0x020000; |
261 | |
262 | # Our package guard gets invoked when we leave our lexical |
263 | # scope. |
264 | |
265 | push(@ { $^H{$PACKAGE_GUARD} }, autodie::Scope::Guard->new(sub { |
266 | $class->_install_subs($pkg, \%unload_later); |
267 | })); |
268 | |
269 | } |
270 | |
271 | return; |
272 | |
273 | } |
274 | |
275 | # The code here is originally lifted from namespace::clean, |
276 | # by Robert "phaylon" Sedlacek. |
277 | # |
278 | # It's been redesigned after feedback from ikegami on perlmonks. |
279 | # See http://perlmonks.org/?node_id=693338 . Ikegami rocks. |
280 | # |
281 | # Given a package, and hash of (subname => subref) pairs, |
282 | # we install the given subroutines into the package. If |
283 | # a subref is undef, the subroutine is removed. Otherwise |
284 | # it replaces any existing subs which were already there. |
285 | |
286 | sub _install_subs { |
287 | my ($class, $pkg, $subs_to_reinstate) = @_; |
288 | |
289 | my $pkg_sym = "${pkg}::"; |
290 | |
291 | while(my ($sub_name, $sub_ref) = each %$subs_to_reinstate) { |
292 | |
293 | my $full_path = $pkg_sym.$sub_name; |
294 | |
295 | # Copy symbols across to temp area. |
296 | |
297 | no strict 'refs'; ## no critic |
298 | |
299 | local *__tmp = *{ $full_path }; |
300 | |
301 | # Nuke the old glob. |
302 | { no strict; delete $pkg_sym->{$sub_name}; } ## no critic |
303 | |
304 | # Copy innocent bystanders back. |
305 | |
306 | foreach my $slot (qw( SCALAR ARRAY HASH IO FORMAT ) ) { |
307 | next unless defined *__tmp{ $slot }; |
308 | *{ $full_path } = *__tmp{ $slot }; |
309 | } |
310 | |
311 | # Put back the old sub (if there was one). |
312 | |
313 | if ($sub_ref) { |
314 | |
315 | no strict; ## no critic |
316 | *{ $pkg_sym . $sub_name } = $sub_ref; |
317 | } |
318 | } |
319 | |
320 | return; |
321 | } |
322 | |
323 | sub unimport { |
324 | my $class = shift; |
325 | |
326 | # Calling "no Fatal" must start with ":lexical" |
327 | if ($_[0] ne LEXICAL_TAG) { |
328 | croak(sprintf(ERROR_NO_LEX,$class)); |
329 | } |
330 | |
331 | shift @_; # Remove :lexical |
332 | |
333 | my $pkg = (caller)[0]; |
334 | |
335 | # If we've been called with arguments, then the developer |
336 | # has explicitly stated 'no autodie qw(blah)', |
337 | # in which case, we disable Fatalistic behaviour for 'blah'. |
338 | |
339 | my @unimport_these = @_ ? @_ : ':all'; |
340 | |
341 | while (my $symbol = shift @unimport_these) { |
342 | |
343 | if ($symbol =~ /^:/) { |
344 | |
345 | # Looks like a tag! Expand it! |
346 | push(@unimport_these, @{ $TAGS{$symbol} }); |
347 | |
348 | next; |
349 | } |
350 | |
351 | my $sub = $symbol; |
352 | $sub = "${pkg}::$sub" unless $sub =~ /::/; |
353 | |
354 | # If 'blah' was already enabled with Fatal (which has package |
355 | # scope) then, this is considered an error. |
356 | |
357 | if (exists $Package_Fatal{$sub}) { |
358 | croak(sprintf(ERROR_AUTODIE_CONFLICT,$symbol,$symbol)); |
359 | } |
360 | |
361 | # Record 'no autodie qw($sub)' as being in effect. |
362 | # This is to catch conflicting semantics elsewhere |
363 | # (eg, mixing Fatal with no autodie) |
364 | |
365 | $^H{$NO_PACKAGE}{$sub} = 1; |
366 | |
367 | if (my $original_sub = $Original_user_sub{$sub}) { |
368 | # Hey, we've got an original one of these, put it back. |
369 | $class->_install_subs($pkg, { $symbol => $original_sub }); |
370 | next; |
371 | } |
372 | |
373 | # We don't have an original copy of the sub, on the assumption |
374 | # it's core (or doesn't exist), we'll just nuke it. |
375 | |
376 | $class->_install_subs($pkg,{ $symbol => undef }); |
377 | |
378 | } |
379 | |
380 | return; |
381 | |
382 | } |
383 | |
384 | # TODO - This is rather terribly inefficient right now. |
385 | |
386 | # NB: Perl::Critic's dump-autodie-tag-contents depends upon this |
387 | # continuing to work. |
388 | |
389 | { |
390 | my %tag_cache; |
391 | |
392 | sub _expand_tag { |
393 | my ($class, $tag) = @_; |
394 | |
395 | if (my $cached = $tag_cache{$tag}) { |
396 | return $cached; |
397 | } |
398 | |
399 | if (not exists $TAGS{$tag}) { |
400 | croak "Invalid exception class $tag"; |
401 | } |
402 | |
403 | my @to_process = @{$TAGS{$tag}}; |
404 | |
405 | my @taglist = (); |
406 | |
407 | while (my $item = shift @to_process) { |
408 | if ($item =~ /^:/) { |
409 | push(@to_process, @{$TAGS{$item}} ); |
410 | } else { |
411 | push(@taglist, "CORE::$item"); |
412 | } |
413 | } |
414 | |
415 | $tag_cache{$tag} = \@taglist; |
416 | |
417 | return \@taglist; |
418 | |
419 | } |
420 | |
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421 | } |
422 | |
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423 | # This code is from the original Fatal. It scares me. |
424 | |
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425 | sub fill_protos { |
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426 | my $proto = shift; |
427 | my ($n, $isref, @out, @out1, $seen_semi) = -1; |
428 | while ($proto =~ /\S/) { |
429 | $n++; |
430 | push(@out1,[$n,@out]) if $seen_semi; |
431 | push(@out, $1 . "{\$_[$n]}"), next if $proto =~ s/^\s*\\([\@%\$\&])//; |
432 | push(@out, "\$_[$n]"), next if $proto =~ s/^\s*([_*\$&])//; |
433 | push(@out, "\@_[$n..\$#_]"), last if $proto =~ s/^\s*(;\s*)?\@//; |
434 | $seen_semi = 1, $n--, next if $proto =~ s/^\s*;//; # XXXX ???? |
435 | die "Internal error: Unknown prototype letters: \"$proto\""; |
436 | } |
437 | push(@out1,[$n+1,@out]); |
438 | return @out1; |
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439 | } |
440 | |
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441 | # This generates the code that will become our fatalised subroutine. |
442 | |
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443 | sub write_invocation { |
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444 | my ($class, $core, $call, $name, $void, $lexical, $sub, @argvs) = @_; |
445 | |
446 | if (@argvs == 1) { # No optional arguments |
447 | |
448 | my @argv = @{$argvs[0]}; |
449 | shift @argv; |
450 | |
451 | return $class->one_invocation($core,$call,$name,$void,$sub,! $lexical,@argv); |
452 | |
453 | } else { |
454 | my $else = "\t"; |
455 | my (@out, @argv, $n); |
456 | while (@argvs) { |
457 | @argv = @{shift @argvs}; |
458 | $n = shift @argv; |
459 | |
460 | push @out, "${else}if (\@_ == $n) {\n"; |
461 | $else = "\t} els"; |
462 | |
463 | push @out, $class->one_invocation($core,$call,$name,$void,$sub,! $lexical,@argv); |
464 | } |
465 | push @out, q[ |
466 | } |
467 | die "Internal error: $name(\@_): Do not expect to get ", scalar \@_, " arguments"; |
468 | ]; |
469 | |
470 | return join '', @out; |
471 | } |
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472 | } |
473 | |
474 | sub one_invocation { |
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475 | my ($class, $core, $call, $name, $void, $sub, $back_compat, @argv) = @_; |
476 | |
477 | # If someone is calling us directly (a child class perhaps?) then |
478 | # they could try to mix void without enabling backwards |
479 | # compatibility. We just don't support this at all, so we gripe |
480 | # about it rather than doing something unwise. |
481 | |
482 | if ($void and not $back_compat) { |
483 | Carp::confess("Internal error: :void mode not supported with $class"); |
484 | } |
485 | |
486 | # @argv only contains the results of the in-built prototype |
487 | # function, and is therefore safe to interpolate in the |
488 | # code generators below. |
489 | |
490 | # TODO - The following clobbers context, but that's what the |
491 | # old Fatal did. Do we care? |
492 | |
493 | if ($back_compat) { |
494 | |
495 | # TODO - Use Fatal qw(system) is not yet supported. It should be! |
496 | |
497 | if ($call eq 'CORE::system') { |
498 | return q{ |
499 | croak("UNIMPLEMENTED: use Fatal qw(system) not yet supported."); |
500 | }; |
501 | } |
502 | |
503 | local $" = ', '; |
504 | |
505 | if ($void) { |
506 | return qq/return (defined wantarray)?$call(@argv): |
507 | $call(@argv) || croak "Can't $name(\@_)/ . |
508 | ($core ? ': $!' : ', \$! is \"$!\"') . '"' |
509 | } else { |
510 | return qq{return $call(@argv) || croak "Can't $name(\@_)} . |
511 | ($core ? ': $!' : ', \$! is \"$!\"') . '"'; |
512 | } |
513 | } |
514 | |
515 | # The name of our original function is: |
516 | # $call if the function is CORE |
517 | # $sub if our function is non-CORE |
518 | |
519 | # The reason for this is that $call is what we're actualling |
520 | # calling. For our core functions, this is always |
521 | # CORE::something. However for user-defined subs, we're about to |
522 | # replace whatever it is that we're calling; as such, we actually |
523 | # calling a subroutine ref. |
524 | |
525 | # Unfortunately, none of this tells us the *ultimate* name. |
526 | # For example, if I export 'copy' from File::Copy, I'd like my |
527 | # ultimate name to be File::Copy::copy. |
528 | # |
529 | # TODO - Is there any way to find the ultimate name of a sub, as |
530 | # described above? |
531 | |
532 | my $true_sub_name = $core ? $call : $sub; |
533 | |
534 | if ($call eq 'CORE::system') { |
535 | |
536 | # Leverage IPC::System::Simple if we're making an autodying |
537 | # system. |
538 | |
539 | local $" = ", "; |
540 | |
541 | # We need to stash $@ into $E, rather than using |
542 | # local $@ for the whole sub. If we don't then |
543 | # any exceptions from internal errors in autodie/Fatal |
544 | # will mysteriously disappear before propogating |
545 | # upwards. |
546 | |
547 | return qq{ |
548 | my \$retval; |
549 | my \$E; |
550 | |
551 | |
552 | { |
553 | local \$@; |
554 | |
555 | eval { |
556 | \$retval = IPC::System::Simple::system(@argv); |
557 | }; |
558 | |
559 | \$E = \$@; |
560 | } |
561 | |
562 | if (\$E) { |
563 | |
564 | # XXX - TODO - This can't be overridden in child |
565 | # classes! |
566 | |
567 | die autodie::exception::system->new( |
568 | function => q{CORE::system}, args => [ @argv ], |
569 | message => "\$E", errno => \$!, |
570 | ); |
571 | } |
572 | |
573 | return \$retval; |
574 | }; |
575 | |
576 | } |
577 | |
578 | # Should we be testing to see if our result is defined, or |
579 | # just true? |
580 | my $use_defined_or = exists ( $Use_defined_or{$call} ); |
581 | |
582 | local $" = ', '; |
583 | |
584 | # If we're going to throw an exception, here's the code to use. |
585 | my $die = qq{ |
586 | die $class->throw( |
587 | function => q{$true_sub_name}, args => [ @argv ], |
588 | pragma => q{$class}, errno => \$!, |
589 | ) |
590 | }; |
591 | |
592 | if ($call eq 'CORE::flock') { |
593 | |
594 | # flock needs special treatment. When it fails with |
595 | # LOCK_UN and EWOULDBLOCK, then it's not really fatal, it just |
596 | # means we couldn't get the lock right now. |
597 | |
598 | require POSIX; # For POSIX::EWOULDBLOCK |
599 | |
600 | local $@; # Don't blat anyone else's $@. |
601 | |
602 | # Ensure that our vendor supports EWOULDBLOCK. If they |
603 | # don't (eg, Windows), then we use known values for its |
604 | # equivalent on other systems. |
605 | |
606 | my $EWOULDBLOCK = eval { POSIX::EWOULDBLOCK(); } |
607 | || $_EWOULDBLOCK{$^O} |
608 | || _autocroak("Internal error - can't overload flock - EWOULDBLOCK not defined on this system."); |
609 | |
610 | require Fcntl; # For Fcntl::LOCK_NB |
611 | |
612 | return qq{ |
613 | |
614 | # Try to flock. If successful, return it immediately. |
615 | |
616 | my \$retval = $call(@argv); |
617 | return \$retval if \$retval; |
618 | |
619 | # If we failed, but we're using LOCK_NB and |
620 | # returned EWOULDBLOCK, it's not a real error. |
621 | |
622 | if (\$_[1] & Fcntl::LOCK_NB() and \$! == $EWOULDBLOCK ) { |
623 | return \$retval; |
624 | } |
625 | |
626 | # Otherwise, we failed. Die noisily. |
627 | |
628 | $die; |
629 | |
630 | }; |
631 | } |
632 | |
633 | # AFAIK everything that can be given an unopned filehandle |
634 | # will fail if it tries to use it, so we don't really need |
635 | # the 'unopened' warning class here. Especially since they |
636 | # then report the wrong line number. |
637 | |
638 | return qq{ |
639 | no warnings qw(unopened); |
640 | |
641 | if (wantarray) { |
642 | my \@results = $call(@argv); |
643 | # If we got back nothing, or we got back a single |
644 | # undef, we die. |
645 | if (! \@results or (\@results == 1 and ! defined \$results[0])) { |
646 | $die; |
647 | }; |
648 | return \@results; |
649 | } |
650 | |
651 | # Otherwise, we're in scalar context. |
652 | # We're never in a void context, since we have to look |
653 | # at the result. |
654 | |
655 | my \$result = $call(@argv); |
656 | |
657 | } . ( $use_defined_or ? qq{ |
658 | |
659 | $die if not defined \$result; |
660 | |
661 | return \$result; |
662 | |
663 | } : qq{ |
664 | |
665 | return \$result || $die; |
666 | |
667 | } ) ; |
668 | |
e92e55da |
669 | } |
670 | |
0b09a93a |
671 | # This returns the old copy of the sub, so we can |
672 | # put it back at end of scope. |
673 | |
674 | # TODO : Check to make sure prototypes are restored correctly. |
675 | |
676 | # TODO: Taking a huge list of arguments is awful. Rewriting to |
677 | # take a hash would be lovely. |
678 | |
e92e55da |
679 | sub _make_fatal { |
0b09a93a |
680 | my($class, $sub, $pkg, $void, $lexical, $filename) = @_; |
e92e55da |
681 | my($name, $code, $sref, $real_proto, $proto, $core, $call); |
682 | my $ini = $sub; |
683 | |
684 | $sub = "${pkg}::$sub" unless $sub =~ /::/; |
0b09a93a |
685 | |
686 | # Figure if we're using lexical or package semantics and |
687 | # twiddle the appropriate bits. |
688 | |
689 | if (not $lexical) { |
690 | $Package_Fatal{$sub} = 1; |
691 | } |
692 | |
693 | # TODO - We *should* be able to do skipping, since we know when |
694 | # we've lexicalised / unlexicalised a subroutine. |
695 | |
e92e55da |
696 | $name = $sub; |
697 | $name =~ s/.*::// or $name =~ s/^&//; |
0b09a93a |
698 | |
699 | warn "# _make_fatal: sub=$sub pkg=$pkg name=$name void=$void\n" if $Debug; |
700 | croak(sprintf(ERROR_BADNAME, $class, $name)) unless $name =~ /^\w+$/; |
701 | |
702 | if (defined(&$sub)) { # user subroutine |
703 | |
704 | # This could be something that we've fatalised that |
705 | # was in core. |
706 | |
707 | local $@; # Don't clobber anyone else's $@ |
708 | |
709 | if ( $Package_Fatal{$sub} and eval { prototype "CORE::$name" } ) { |
710 | |
711 | # Something we previously made Fatal that was core. |
712 | # This is safe to replace with an autodying to core |
713 | # version. |
714 | |
715 | $core = 1; |
716 | $call = "CORE::$name"; |
717 | $proto = prototype $call; |
718 | |
719 | # We return our $sref from this subroutine later |
720 | # on, indicating this subroutine should be placed |
721 | # back when we're finished. |
722 | |
723 | $sref = \&$sub; |
724 | |
725 | } else { |
726 | |
727 | # A regular user sub, or a user sub wrapping a |
728 | # core sub. |
729 | |
730 | $sref = \&$sub; |
731 | $proto = prototype $sref; |
732 | $call = '&$sref'; |
733 | |
734 | } |
735 | |
910ad8dd |
736 | } elsif ($sub eq $ini && $sub !~ /^CORE::GLOBAL::/) { |
0b09a93a |
737 | # Stray user subroutine |
738 | croak(sprintf(ERROR_NOTSUB,$sub)); |
739 | |
740 | } elsif ($name eq 'system') { |
741 | |
742 | # If we're fatalising system, then we need to load |
743 | # helper code. |
744 | |
745 | eval { |
746 | require IPC::System::Simple; # Only load it if we need it. |
747 | require autodie::exception::system; |
748 | }; |
749 | |
750 | if ($@) { croak ERROR_NO_IPC_SYS_SIMPLE; } |
751 | |
752 | # Make sure we're using a recent version of ISS that actually |
753 | # support fatalised system. |
754 | if ($IPC::System::Simple::VERSION < MIN_IPC_SYS_SIMPLE_VER) { |
755 | croak sprintf( |
756 | ERROR_IPC_SYS_SIMPLE_OLD, MIN_IPC_SYS_SIMPLE_VER, |
757 | $IPC::System::Simple::VERSION |
758 | ); |
759 | } |
760 | |
761 | $call = 'CORE::system'; |
762 | $name = 'system'; |
db4e6d09 |
763 | $core = 1; |
0b09a93a |
764 | |
765 | } elsif ($name eq 'exec') { |
766 | # Exec doesn't have a prototype. We don't care. This |
767 | # breaks the exotic form with lexical scope, and gives |
768 | # the regular form a "do or die" beaviour as expected. |
769 | |
770 | $call = 'CORE::exec'; |
771 | $name = 'exec'; |
772 | $core = 1; |
773 | |
774 | } else { # CORE subroutine |
e92e55da |
775 | $proto = eval { prototype "CORE::$name" }; |
0b09a93a |
776 | croak(sprintf(ERROR_NOT_BUILT,$name)) if $@; |
777 | croak(sprintf(ERROR_CANT_OVERRIDE,$name)) if not defined $proto; |
778 | $core = 1; |
779 | $call = "CORE::$name"; |
e92e55da |
780 | } |
0b09a93a |
781 | |
e92e55da |
782 | if (defined $proto) { |
0b09a93a |
783 | $real_proto = " ($proto)"; |
e92e55da |
784 | } else { |
0b09a93a |
785 | $real_proto = ''; |
786 | $proto = '@'; |
787 | } |
788 | |
789 | my $true_name = $core ? $call : $sub; |
790 | |
791 | # TODO: This caching works, but I don't like using $void and |
792 | # $lexical as keys. In particular, I suspect our code may end up |
793 | # wrapping already wrapped code when autodie and Fatal are used |
794 | # together. |
795 | |
796 | # NB: We must use '$sub' (the name plus package) and not |
797 | # just '$name' (the short name) here. Failing to do so |
798 | # results code that's in the wrong package, and hence has |
799 | # access to the wrong package filehandles. |
800 | |
801 | if (my $subref = $Cached_fatalised_sub{$class}{$sub}{$void}{$lexical}) { |
802 | $class->_install_subs($pkg, { $name => $subref }); |
803 | return $sref; |
e92e55da |
804 | } |
0b09a93a |
805 | |
806 | $code = qq[ |
807 | sub$real_proto { |
808 | local(\$", \$!) = (', ', 0); # TODO - Why do we do this? |
809 | ]; |
810 | |
811 | # Don't have perl whine if exec fails, since we'll be handling |
812 | # the exception now. |
813 | $code .= "no warnings qw(exec);\n" if $call eq "CORE::exec"; |
814 | |
e92e55da |
815 | my @protos = fill_protos($proto); |
0b09a93a |
816 | $code .= $class->write_invocation($core, $call, $name, $void, $lexical, $sub, @protos); |
e92e55da |
817 | $code .= "}\n"; |
0b09a93a |
818 | warn $code if $Debug; |
819 | |
820 | # I thought that changing package was a monumental waste of |
821 | # time for CORE subs, since they'll always be the same. However |
822 | # that's not the case, since they may refer to package-based |
823 | # filehandles (eg, with open). |
824 | # |
825 | # There is potential to more aggressively cache core subs |
826 | # that we know will never want to interact with package variables |
827 | # and filehandles. |
828 | |
2ba6ecf4 |
829 | { |
0b09a93a |
830 | local $@; |
831 | no strict 'refs'; ## no critic # to avoid: Can't use string (...) as a symbol ref ... |
832 | $code = eval("package $pkg; use Carp; $code"); ## no critic |
833 | if (not $code) { |
834 | |
835 | # For some reason, using a die, croak, or confess in here |
836 | # results in the error being completely surpressed. As such, |
837 | # we need to do our own reporting. |
838 | # |
839 | # TODO: Fix the above. |
840 | |
841 | _autocroak("Internal error in autodie/Fatal processing $true_name: $@"); |
842 | |
843 | } |
844 | } |
845 | |
846 | # Now we need to wrap our fatalised sub inside an itty bitty |
847 | # closure, which can detect if we've leaked into another file. |
848 | # Luckily, we only need to do this for lexical (autodie) |
849 | # subs. Fatal subs can leak all they want, it's considered |
850 | # a "feature" (or at least backwards compatible). |
851 | |
852 | # TODO: Cache our leak guards! |
853 | |
854 | # TODO: This is pretty hairy code. A lot more tests would |
855 | # be really nice for this. |
856 | |
857 | my $leak_guard; |
858 | |
859 | if ($lexical) { |
860 | |
861 | $leak_guard = qq< |
862 | package $pkg; |
863 | |
864 | sub$real_proto { |
865 | |
db4e6d09 |
866 | # If we're inside a string eval, we can end up with a |
867 | # whacky filename. The following code allows autodie |
868 | # to propagate correctly into string evals. |
869 | |
870 | my \$caller_level = 0; |
871 | |
872 | while ( (caller \$caller_level)[1] =~ m{^\\(eval \\d+\\)\$} ) { |
873 | \$caller_level++; |
874 | } |
875 | |
0b09a93a |
876 | # If we're called from the correct file, then use the |
877 | # autodying code. |
db4e6d09 |
878 | goto &\$code if ((caller \$caller_level)[1] eq \$filename); |
0b09a93a |
879 | |
880 | # Oh bother, we've leaked into another file. Call the |
881 | # original code. Note that \$sref may actually be a |
882 | # reference to a Fatalised version of a core built-in. |
883 | # That's okay, because Fatal *always* leaks between files. |
884 | |
885 | goto &\$sref if \$sref; |
886 | >; |
887 | |
888 | |
889 | # If we're here, it must have been a core subroutine called. |
890 | # Warning: The following code may disturb some viewers. |
891 | |
892 | # TODO: It should be possible to combine this with |
893 | # write_invocation(). |
894 | |
895 | foreach my $proto (@protos) { |
896 | local $" = ", "; # So @args is formatted correctly. |
897 | my ($count, @args) = @$proto; |
898 | $leak_guard .= qq< |
899 | if (\@_ == $count) { |
900 | return $call(@args); |
901 | } |
902 | >; |
903 | } |
904 | |
905 | $leak_guard .= qq< croak "Internal error in Fatal/autodie. Leak-guard failure"; } >; |
906 | |
907 | # warn "$leak_guard\n"; |
908 | |
909 | local $@; |
910 | |
911 | $leak_guard = eval $leak_guard; ## no critic |
912 | |
913 | die "Internal error in $class: Leak-guard installation failure: $@" if $@; |
914 | } |
915 | |
916 | $class->_install_subs($pkg, { $name => $leak_guard || $code }); |
917 | |
918 | $Cached_fatalised_sub{$class}{$sub}{$void}{$lexical} = $leak_guard || $code; |
919 | |
920 | return $sref; |
921 | |
922 | } |
923 | |
924 | # This subroutine exists primarily so that child classes can override |
925 | # it to point to their own exception class. Doing this is significantly |
926 | # less complex than overriding throw() |
927 | |
928 | sub exception_class { return "autodie::exception" }; |
929 | |
930 | { |
931 | my %exception_class_for; |
932 | my %class_loaded; |
933 | |
934 | sub throw { |
935 | my ($class, @args) = @_; |
936 | |
937 | # Find our exception class if we need it. |
938 | my $exception_class = |
939 | $exception_class_for{$class} ||= $class->exception_class; |
940 | |
941 | if (not $class_loaded{$exception_class}) { |
942 | if ($exception_class =~ /[^\w:']/) { |
943 | confess "Bad exception class '$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."; |
944 | } |
945 | |
946 | # Alas, Perl does turn barewords into modules unless they're |
947 | # actually barewords. As such, we're left doing a string eval |
948 | # to make sure we load our file correctly. |
949 | |
950 | my $E; |
951 | |
952 | { |
953 | local $@; # We can't clobber $@, it's wrong! |
954 | eval "require $exception_class"; ## no critic |
955 | $E = $@; # Save $E despite ending our local. |
956 | } |
957 | |
958 | # We need quotes around $@ to make sure it's stringified |
959 | # while still in scope. Without them, we run the risk of |
960 | # $@ having been cleared by us exiting the local() block. |
961 | |
962 | confess "Failed to load '$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; |
963 | |
964 | $class_loaded{$exception_class}++; |
965 | |
966 | } |
967 | |
968 | return $exception_class->new(@args); |
2ba6ecf4 |
969 | } |
e92e55da |
970 | } |
971 | |
0b09a93a |
972 | # For some reason, dying while replacing our subs doesn't |
973 | # kill our calling program. It simply stops the loading of |
974 | # autodie and keeps going with everything else. The _autocroak |
975 | # sub allows us to die with a vegence. It should *only* ever be |
976 | # used for serious internal errors, since the results of it can't |
977 | # be captured. |
978 | |
979 | sub _autocroak { |
980 | warn Carp::longmess(@_); |
981 | exit(255); # Ugh! |
982 | } |
983 | |
984 | package autodie::Scope::Guard; |
985 | |
986 | # This code schedules the cleanup of subroutines at the end of |
987 | # scope. It's directly inspired by chocolateboy's excellent |
988 | # Scope::Guard module. |
989 | |
990 | sub new { |
991 | my ($class, $handler) = @_; |
992 | |
993 | return bless $handler, $class; |
994 | } |
995 | |
996 | sub DESTROY { |
997 | my ($self) = @_; |
998 | |
999 | $self->(); |
1000 | } |
1001 | |
e92e55da |
1002 | 1; |
1003 | |
1004 | __END__ |
1005 | |
1006 | =head1 NAME |
1007 | |
0b09a93a |
1008 | Fatal - Replace functions with equivalents which succeed or die |
e92e55da |
1009 | |
1010 | =head1 SYNOPSIS |
1011 | |
1012 | use Fatal qw(open close); |
1013 | |
0b09a93a |
1014 | open(my $fh, "<", $filename); # No need to check errors! |
1015 | |
1016 | use File::Copy qw(move); |
1017 | use Fatal qw(move); |
1018 | |
1019 | move($file1, $file2); # No need to check errors! |
1020 | |
e92e55da |
1021 | sub juggle { . . . } |
0b09a93a |
1022 | Fatal->import('juggle'); |
1023 | |
1024 | =head1 BEST PRACTICE |
1025 | |
1026 | B<Fatal has been obsoleted by the new L<autodie> pragma.> Please use |
1027 | L<autodie> in preference to C<Fatal>. L<autodie> supports lexical scoping, |
1028 | throws real exception objects, and provides much nicer error messages. |
1029 | |
1030 | The use of C<:void> with Fatal is discouraged. |
e92e55da |
1031 | |
1032 | =head1 DESCRIPTION |
1033 | |
0b09a93a |
1034 | C<Fatal> provides a way to conveniently replace |
1035 | functions which normally return a false value when they fail with |
1036 | equivalents which raise exceptions if they are not successful. This |
1037 | lets you use these functions without having to test their return |
1038 | values explicitly on each call. Exceptions can be caught using |
1039 | C<eval{}>. See L<perlfunc> and L<perlvar> for details. |
e92e55da |
1040 | |
1041 | The do-or-die equivalents are set up simply by calling Fatal's |
1042 | C<import> routine, passing it the names of the functions to be |
1043 | replaced. You may wrap both user-defined functions and overridable |
0b09a93a |
1044 | CORE operators (except C<exec>, C<system>, C<print>, or any other |
1045 | built-in that cannot be expressed via prototypes) in this way. |
e92e55da |
1046 | |
91c7a880 |
1047 | If the symbol C<:void> appears in the import list, then functions |
1048 | named later in that import list raise an exception only when |
1049 | these are called in void context--that is, when their return |
1050 | values are ignored. For example |
1051 | |
0b09a93a |
1052 | use Fatal qw/:void open close/; |
91c7a880 |
1053 | |
0b09a93a |
1054 | # properly checked, so no exception raised on error |
1055 | if (not open(my $fh, '<' '/bogotic') { |
1056 | warn "Can't open /bogotic: $!"; |
1057 | } |
91c7a880 |
1058 | |
0b09a93a |
1059 | # not checked, so error raises an exception |
1060 | close FH; |
1061 | |
1062 | The use of C<:void> is discouraged, as it can result in exceptions |
1063 | not being thrown if you I<accidentally> call a method without |
1064 | void context. Use L<autodie> instead if you need to be able to |
1065 | disable autodying/Fatal behaviour for a small block of code. |
1066 | |
1067 | =head1 DIAGNOSTICS |
1068 | |
1069 | =over 4 |
1070 | |
1071 | =item Bad subroutine name for Fatal: %s |
1072 | |
1073 | You've called C<Fatal> with an argument that doesn't look like |
1074 | a subroutine name, nor a switch that this version of Fatal |
1075 | understands. |
1076 | |
1077 | =item %s is not a Perl subroutine |
1078 | |
1079 | You've asked C<Fatal> to try and replace a subroutine which does not |
1080 | exist, or has not yet been defined. |
1081 | |
1082 | =item %s is neither a builtin, nor a Perl subroutine |
1083 | |
1084 | You've asked C<Fatal> to replace a subroutine, but it's not a Perl |
1085 | built-in, and C<Fatal> couldn't find it as a regular subroutine. |
1086 | It either doesn't exist or has not yet been defined. |
1087 | |
1088 | =item Cannot make the non-overridable %s fatal |
1089 | |
1090 | You've tried to use C<Fatal> on a Perl built-in that can't be |
1091 | overridden, such as C<print> or C<system>, which means that |
1092 | C<Fatal> can't help you, although some other modules might. |
1093 | See the L</"SEE ALSO"> section of this documentation. |
1094 | |
1095 | =item Internal error: %s |
1096 | |
1097 | You've found a bug in C<Fatal>. Please report it using |
1098 | the C<perlbug> command. |
1099 | |
1100 | =back |
91c7a880 |
1101 | |
a6fd7f3f |
1102 | =head1 BUGS |
1103 | |
0b09a93a |
1104 | C<Fatal> clobbers the context in which a function is called and always |
1105 | makes it a scalar context, except when the C<:void> tag is used. |
1106 | This problem does not exist in L<autodie>. |
a6fd7f3f |
1107 | |
3776a202 |
1108 | "Used only once" warnings can be generated when C<autodie> or C<Fatal> |
1109 | is used with package filehandles (eg, C<FILE>). It's strongly recommended |
1110 | you use scalar filehandles instead. |
1111 | |
e92e55da |
1112 | =head1 AUTHOR |
1113 | |
0b09a93a |
1114 | Original module by Lionel Cons (CERN). |
e92e55da |
1115 | |
10af26ed |
1116 | Prototype updates by Ilya Zakharevich <ilya@math.ohio-state.edu>. |
e92e55da |
1117 | |
0b09a93a |
1118 | L<autodie> support, bugfixes, extended diagnostics, C<system> |
1119 | support, and major overhauling by Paul Fenwick <pjf@perltraining.com.au> |
1120 | |
1121 | =head1 LICENSE |
1122 | |
1123 | This module is free software, you may distribute it under the |
1124 | same terms as Perl itself. |
1125 | |
1126 | =head1 SEE ALSO |
1127 | |
1128 | L<autodie> for a nicer way to use lexical Fatal. |
1129 | |
1130 | L<IPC::System::Simple> for a similar idea for calls to C<system()> |
1131 | and backticks. |
1132 | |
e92e55da |
1133 | =cut |