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e92e55da MB |
1 | package Fatal; |
2 | ||
0b09a93a | 3 | use 5.008; # 5.8.x needed for autodie |
e92e55da MB |
4 | use Carp; |
5 | use strict; | |
0b09a93a | 6 | use warnings; |
e92e55da | 7 | |
0b09a93a PF |
8 | use constant LEXICAL_TAG => q{:lexical}; |
9 | use constant VOID_TAG => q{:void}; | |
e92e55da | 10 | |
0b09a93a PF |
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'. | |
e92e55da MB |
143 | |
144 | sub import { | |
0b09a93a PF |
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 | ||
e92e55da MB |
419 | } |
420 | ||
0b09a93a PF |
421 | # This code is from the original Fatal. It scares me. |
422 | ||
e92e55da | 423 | sub fill_protos { |
0b09a93a PF |
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,[$n+1,@out]); | |
436 | return @out1; | |
e92e55da MB |
437 | } |
438 | ||
0b09a93a PF |
439 | # This generates the code that will become our fatalised subroutine. |
440 | ||
e92e55da | 441 | sub write_invocation { |
0b09a93a PF |
442 | my ($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: $name(\@_): Do not expect to get ", scalar \@_, " arguments"; | |
466 | ]; | |
467 | ||
468 | return join '', @out; | |
469 | } | |
e92e55da MB |
470 | } |
471 | ||
472 | sub one_invocation { | |
0b09a93a PF |
473 | my ($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 || $die; | |
664 | ||
665 | } ) ; | |
666 | ||
e92e55da MB |
667 | } |
668 | ||
0b09a93a PF |
669 | # This returns the old copy of the sub, so we can |
670 | # put it back at end of scope. | |
671 | ||
672 | # TODO : Check to make sure prototypes are restored correctly. | |
673 | ||
674 | # TODO: Taking a huge list of arguments is awful. Rewriting to | |
675 | # take a hash would be lovely. | |
676 | ||
e92e55da | 677 | sub _make_fatal { |
0b09a93a | 678 | my($class, $sub, $pkg, $void, $lexical, $filename) = @_; |
e92e55da MB |
679 | my($name, $code, $sref, $real_proto, $proto, $core, $call); |
680 | my $ini = $sub; | |
681 | ||
682 | $sub = "${pkg}::$sub" unless $sub =~ /::/; | |
0b09a93a PF |
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 MB |
694 | $name = $sub; |
695 | $name =~ s/.*::// or $name =~ s/^&//; | |
0b09a93a PF |
696 | |
697 | warn "# _make_fatal: sub=$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 && $sub !~ /^CORE::GLOBAL::/) { |
0b09a93a PF |
735 | # Stray user subroutine |
736 | croak(sprintf(ERROR_NOTSUB,$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 PF |
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 PF |
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 PF |
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 PF |
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 PF |
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 $exception_class->new(@args); | |
2ba6ecf4 | 956 | } |
e92e55da MB |
957 | } |
958 | ||
0b09a93a PF |
959 | # For some reason, dying while replacing our subs doesn't |
960 | # kill our calling program. It simply stops the loading of | |
961 | # autodie and keeps going with everything else. The _autocroak | |
962 | # sub allows us to die with a vegence. It should *only* ever be | |
963 | # used for serious internal errors, since the results of it can't | |
964 | # be captured. | |
965 | ||
966 | sub _autocroak { | |
967 | warn Carp::longmess(@_); | |
968 | exit(255); # Ugh! | |
969 | } | |
970 | ||
971 | package autodie::Scope::Guard; | |
972 | ||
973 | # This code schedules the cleanup of subroutines at the end of | |
974 | # scope. It's directly inspired by chocolateboy's excellent | |
975 | # Scope::Guard module. | |
976 | ||
977 | sub new { | |
978 | my ($class, $handler) = @_; | |
979 | ||
980 | return bless $handler, $class; | |
981 | } | |
982 | ||
983 | sub DESTROY { | |
984 | my ($self) = @_; | |
985 | ||
986 | $self->(); | |
987 | } | |
988 | ||
e92e55da MB |
989 | 1; |
990 | ||
991 | __END__ | |
992 | ||
993 | =head1 NAME | |
994 | ||
0b09a93a | 995 | Fatal - Replace functions with equivalents which succeed or die |
e92e55da MB |
996 | |
997 | =head1 SYNOPSIS | |
998 | ||
999 | use Fatal qw(open close); | |
1000 | ||
0b09a93a PF |
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 PF |
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 MB |
1018 | |
1019 | =head1 DESCRIPTION | |
1020 | ||
0b09a93a PF |
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 MB |
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 PF |
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 GS |
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 PF |
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 PF |
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 RGS |
1089 | =head1 BUGS |
1090 | ||
0b09a93a PF |
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 MB |
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 PF |
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 |