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1 | package ExtUtils::Constant; |
2 | use vars qw (@ISA $VERSION @EXPORT_OK %EXPORT_TAGS); | |
3 | $VERSION = 0.17; | |
4 | ||
5 | =head1 NAME | |
6 | ||
7 | ExtUtils::Constant - generate XS code to import C header constants | |
8 | ||
9 | =head1 SYNOPSIS | |
10 | ||
11 | use ExtUtils::Constant qw (WriteConstants); | |
12 | WriteConstants( | |
13 | NAME => 'Foo', | |
14 | NAMES => [qw(FOO BAR BAZ)], | |
15 | ); | |
16 | # Generates wrapper code to make the values of the constants FOO BAR BAZ | |
17 | # available to perl | |
18 | ||
19 | =head1 DESCRIPTION | |
20 | ||
21 | ExtUtils::Constant facilitates generating C and XS wrapper code to allow | |
22 | perl modules to AUTOLOAD constants defined in C library header files. | |
23 | It is principally used by the C<h2xs> utility, on which this code is based. | |
24 | It doesn't contain the routines to scan header files to extract these | |
25 | constants. | |
26 | ||
27 | =head1 USAGE | |
28 | ||
29 | Generally one only needs to call the C<WriteConstants> function, and then | |
30 | ||
31 | #include "const-c.inc" | |
32 | ||
33 | in the C section of C<Foo.xs> | |
34 | ||
35 | INCLUDE: const-xs.inc | |
36 | ||
37 | in the XS section of C<Foo.xs>. | |
38 | ||
39 | For greater flexibility use C<constant_types()>, C<C_constant> and | |
40 | C<XS_constant>, with which C<WriteConstants> is implemented. | |
41 | ||
42 | Currently this module understands the following types. h2xs may only know | |
43 | a subset. The sizes of the numeric types are chosen by the C<Configure> | |
44 | script at compile time. | |
45 | ||
46 | =over 4 | |
47 | ||
48 | =item IV | |
49 | ||
50 | signed integer, at least 32 bits. | |
51 | ||
52 | =item UV | |
53 | ||
54 | unsigned integer, the same size as I<IV> | |
55 | ||
56 | =item NV | |
57 | ||
58 | floating point type, probably C<double>, possibly C<long double> | |
59 | ||
60 | =item PV | |
61 | ||
62 | NUL terminated string, length will be determined with C<strlen> | |
63 | ||
64 | =item PVN | |
65 | ||
66 | A fixed length thing, given as a [pointer, length] pair. If you know the | |
67 | length of a string at compile time you may use this instead of I<PV> | |
68 | ||
69 | =item SV | |
70 | ||
71 | A B<mortal> SV. | |
72 | ||
73 | =item YES | |
74 | ||
75 | Truth. (C<PL_sv_yes>) The value is not needed (and ignored). | |
76 | ||
77 | =item NO | |
78 | ||
79 | Defined Falsehood. (C<PL_sv_no>) The value is not needed (and ignored). | |
80 | ||
81 | =item UNDEF | |
82 | ||
83 | C<undef>. The value of the macro is not needed. | |
84 | ||
85 | =back | |
86 | ||
87 | =head1 FUNCTIONS | |
88 | ||
89 | =over 4 | |
90 | ||
91 | =cut | |
92 | ||
93 | if ($] >= 5.006) { | |
94 | eval "use warnings; 1" or die $@; | |
95 | } | |
96 | use strict; | |
97 | use Carp qw(croak cluck); | |
98 | ||
99 | use Exporter; | |
100 | use ExtUtils::Constant::Utils qw(C_stringify); | |
101 | use ExtUtils::Constant::XS qw(%XS_Constant %XS_TypeSet); | |
102 | ||
103 | @ISA = 'Exporter'; | |
104 | ||
105 | %EXPORT_TAGS = ( 'all' => [ qw( | |
106 | XS_constant constant_types return_clause memEQ_clause C_stringify | |
107 | C_constant autoload WriteConstants WriteMakefileSnippet | |
108 | ) ] ); | |
109 | ||
110 | @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } ); | |
111 | ||
112 | =item constant_types | |
113 | ||
114 | A function returning a single scalar with C<#define> definitions for the | |
115 | constants used internally between the generated C and XS functions. | |
116 | ||
117 | =cut | |
118 | ||
119 | sub constant_types { | |
120 | ExtUtils::Constant::XS->header(); | |
121 | } | |
122 | ||
123 | sub memEQ_clause { | |
124 | cluck "ExtUtils::Constant::memEQ_clause is deprecated"; | |
125 | ExtUtils::Constant::XS->memEQ_clause({name=>$_[0], checked_at=>$_[1], | |
126 | indent=>$_[2]}); | |
127 | } | |
128 | ||
129 | sub return_clause ($$) { | |
130 | cluck "ExtUtils::Constant::return_clause is deprecated"; | |
131 | my $indent = shift; | |
132 | ExtUtils::Constant::XS->return_clause({indent=>$indent}, @_); | |
133 | } | |
134 | ||
135 | sub switch_clause { | |
136 | cluck "ExtUtils::Constant::switch_clause is deprecated"; | |
137 | my $indent = shift; | |
138 | my $comment = shift; | |
139 | ExtUtils::Constant::XS->switch_clause({indent=>$indent, comment=>$comment}, | |
140 | @_); | |
141 | } | |
142 | ||
143 | sub C_constant { | |
144 | my ($package, $subname, $default_type, $what, $indent, $breakout, @items) | |
145 | = @_; | |
146 | ExtUtils::Constant::XS->C_constant({package => $package, subname => $subname, | |
147 | default_type => $default_type, | |
148 | types => $what, indent => $indent, | |
149 | breakout => $breakout}, @items); | |
150 | } | |
151 | ||
152 | =item XS_constant PACKAGE, TYPES, SUBNAME, C_SUBNAME | |
153 | ||
154 | A function to generate the XS code to implement the perl subroutine | |
155 | I<PACKAGE>::constant used by I<PACKAGE>::AUTOLOAD to load constants. | |
156 | This XS code is a wrapper around a C subroutine usually generated by | |
157 | C<C_constant>, and usually named C<constant>. | |
158 | ||
159 | I<TYPES> should be given either as a comma separated list of types that the | |
160 | C subroutine C<constant> will generate or as a reference to a hash. It should | |
161 | be the same list of types as C<C_constant> was given. | |
162 | [Otherwise C<XS_constant> and C<C_constant> may have different ideas about | |
163 | the number of parameters passed to the C function C<constant>] | |
164 | ||
165 | You can call the perl visible subroutine something other than C<constant> if | |
166 | you give the parameter I<SUBNAME>. The C subroutine it calls defaults to | |
167 | the name of the perl visible subroutine, unless you give the parameter | |
168 | I<C_SUBNAME>. | |
169 | ||
170 | =cut | |
171 | ||
172 | sub XS_constant { | |
173 | my $package = shift; | |
174 | my $what = shift; | |
175 | my $subname = shift; | |
176 | my $C_subname = shift; | |
177 | $subname ||= 'constant'; | |
178 | $C_subname ||= $subname; | |
179 | ||
180 | if (!ref $what) { | |
181 | # Convert line of the form IV,UV,NV to hash | |
182 | $what = {map {$_ => 1} split /,\s*/, ($what)}; | |
183 | } | |
184 | my $params = ExtUtils::Constant::XS->params ($what); | |
185 | my $type; | |
186 | ||
187 | my $xs = <<"EOT"; | |
188 | void | |
189 | $subname(sv) | |
190 | PREINIT: | |
191 | #ifdef dXSTARG | |
192 | dXSTARG; /* Faster if we have it. */ | |
193 | #else | |
194 | dTARGET; | |
195 | #endif | |
196 | STRLEN len; | |
197 | int type; | |
198 | EOT | |
199 | ||
200 | if ($params->{IV}) { | |
201 | $xs .= " IV iv;\n"; | |
202 | } else { | |
203 | $xs .= " /* IV\t\tiv;\tUncomment this if you need to return IVs */\n"; | |
204 | } | |
205 | if ($params->{NV}) { | |
206 | $xs .= " NV nv;\n"; | |
207 | } else { | |
208 | $xs .= " /* NV\t\tnv;\tUncomment this if you need to return NVs */\n"; | |
209 | } | |
210 | if ($params->{PV}) { | |
211 | $xs .= " const char *pv;\n"; | |
212 | } else { | |
213 | $xs .= | |
214 | " /* const char\t*pv;\tUncomment this if you need to return PVs */\n"; | |
215 | } | |
216 | ||
217 | $xs .= << 'EOT'; | |
218 | INPUT: | |
219 | SV * sv; | |
220 | const char * s = SvPV(sv, len); | |
221 | EOT | |
222 | if ($params->{''}) { | |
223 | $xs .= << 'EOT'; | |
224 | INPUT: | |
225 | int utf8 = SvUTF8(sv); | |
226 | EOT | |
227 | } | |
228 | $xs .= << 'EOT'; | |
229 | PPCODE: | |
230 | EOT | |
231 | ||
232 | if ($params->{IV} xor $params->{NV}) { | |
233 | $xs .= << "EOT"; | |
234 | /* Change this to $C_subname(aTHX_ s, len, &iv, &nv); | |
235 | if you need to return both NVs and IVs */ | |
236 | EOT | |
237 | } | |
238 | $xs .= " type = $C_subname(aTHX_ s, len"; | |
239 | $xs .= ', utf8' if $params->{''}; | |
240 | $xs .= ', &iv' if $params->{IV}; | |
241 | $xs .= ', &nv' if $params->{NV}; | |
242 | $xs .= ', &pv' if $params->{PV}; | |
243 | $xs .= ', &sv' if $params->{SV}; | |
244 | $xs .= ");\n"; | |
245 | ||
246 | $xs .= << "EOT"; | |
247 | /* Return 1 or 2 items. First is error message, or undef if no error. | |
248 | Second, if present, is found value */ | |
249 | switch (type) { | |
250 | case PERL_constant_NOTFOUND: | |
251 | sv = sv_2mortal(newSVpvf("%s is not a valid $package macro", s)); | |
252 | PUSHs(sv); | |
253 | break; | |
254 | case PERL_constant_NOTDEF: | |
255 | sv = sv_2mortal(newSVpvf( | |
256 | "Your vendor has not defined $package macro %s, used", s)); | |
257 | PUSHs(sv); | |
258 | break; | |
259 | EOT | |
260 | ||
261 | foreach $type (sort keys %XS_Constant) { | |
262 | # '' marks utf8 flag needed. | |
263 | next if $type eq ''; | |
264 | $xs .= "\t/* Uncomment this if you need to return ${type}s\n" | |
265 | unless $what->{$type}; | |
266 | $xs .= " case PERL_constant_IS$type:\n"; | |
267 | if (length $XS_Constant{$type}) { | |
268 | $xs .= << "EOT"; | |
269 | EXTEND(SP, 1); | |
270 | PUSHs(&PL_sv_undef); | |
271 | $XS_Constant{$type}; | |
272 | EOT | |
273 | } else { | |
274 | # Do nothing. return (), which will be correctly interpreted as | |
275 | # (undef, undef) | |
276 | } | |
277 | $xs .= " break;\n"; | |
278 | unless ($what->{$type}) { | |
279 | chop $xs; # Yes, another need for chop not chomp. | |
280 | $xs .= " */\n"; | |
281 | } | |
282 | } | |
283 | $xs .= << "EOT"; | |
284 | default: | |
285 | sv = sv_2mortal(newSVpvf( | |
286 | "Unexpected return type %d while processing $package macro %s, used", | |
287 | type, s)); | |
288 | PUSHs(sv); | |
289 | } | |
290 | EOT | |
291 | ||
292 | return $xs; | |
293 | } | |
294 | ||
295 | ||
296 | =item autoload PACKAGE, VERSION, AUTOLOADER | |
297 | ||
298 | A function to generate the AUTOLOAD subroutine for the module I<PACKAGE> | |
299 | I<VERSION> is the perl version the code should be backwards compatible with. | |
300 | It defaults to the version of perl running the subroutine. If I<AUTOLOADER> | |
301 | is true, the AUTOLOAD subroutine falls back on AutoLoader::AUTOLOAD for all | |
302 | names that the constant() routine doesn't recognise. | |
303 | ||
304 | =cut | |
305 | ||
306 | # ' # Grr. syntax highlighters that don't grok pod. | |
307 | ||
308 | sub autoload { | |
309 | my ($module, $compat_version, $autoloader) = @_; | |
310 | $compat_version ||= $]; | |
311 | croak "Can't maintain compatibility back as far as version $compat_version" | |
312 | if $compat_version < 5; | |
313 | my $func = "sub AUTOLOAD {\n" | |
314 | . " # This AUTOLOAD is used to 'autoload' constants from the constant()\n" | |
315 | . " # XS function."; | |
316 | $func .= " If a constant is not found then control is passed\n" | |
317 | . " # to the AUTOLOAD in AutoLoader." if $autoloader; | |
318 | ||
319 | ||
320 | $func .= "\n\n" | |
321 | . " my \$constname;\n"; | |
322 | $func .= | |
323 | " our \$AUTOLOAD;\n" if ($compat_version >= 5.006); | |
324 | ||
325 | $func .= <<"EOT"; | |
326 | (\$constname = \$AUTOLOAD) =~ s/.*:://; | |
327 | croak "&${module}::constant not defined" if \$constname eq 'constant'; | |
328 | my (\$error, \$val) = constant(\$constname); | |
329 | EOT | |
330 | ||
331 | if ($autoloader) { | |
332 | $func .= <<'EOT'; | |
333 | if ($error) { | |
334 | if ($error =~ /is not a valid/) { | |
335 | $AutoLoader::AUTOLOAD = $AUTOLOAD; | |
336 | goto &AutoLoader::AUTOLOAD; | |
337 | } else { | |
338 | croak $error; | |
339 | } | |
340 | } | |
341 | EOT | |
342 | } else { | |
343 | $func .= | |
344 | " if (\$error) { croak \$error; }\n"; | |
345 | } | |
346 | ||
347 | $func .= <<'END'; | |
348 | { | |
349 | no strict 'refs'; | |
350 | # Fixed between 5.005_53 and 5.005_61 | |
351 | #XXX if ($] >= 5.00561) { | |
352 | #XXX *$AUTOLOAD = sub () { $val }; | |
353 | #XXX } | |
354 | #XXX else { | |
355 | *$AUTOLOAD = sub { $val }; | |
356 | #XXX } | |
357 | } | |
358 | goto &$AUTOLOAD; | |
359 | } | |
360 | ||
361 | END | |
362 | ||
363 | return $func; | |
364 | } | |
365 | ||
366 | ||
367 | =item WriteMakefileSnippet | |
368 | ||
369 | WriteMakefileSnippet ATTRIBUTE =E<gt> VALUE [, ...] | |
370 | ||
371 | A function to generate perl code for Makefile.PL that will regenerate | |
372 | the constant subroutines. Parameters are named as passed to C<WriteConstants>, | |
373 | with the addition of C<INDENT> to specify the number of leading spaces | |
374 | (default 2). | |
375 | ||
376 | Currently only C<INDENT>, C<NAME>, C<DEFAULT_TYPE>, C<NAMES>, C<C_FILE> and | |
377 | C<XS_FILE> are recognised. | |
378 | ||
379 | =cut | |
380 | ||
381 | sub WriteMakefileSnippet { | |
382 | my %args = @_; | |
383 | my $indent = $args{INDENT} || 2; | |
384 | ||
385 | my $result = <<"EOT"; | |
386 | ExtUtils::Constant::WriteConstants( | |
387 | NAME => '$args{NAME}', | |
388 | NAMES => \\\@names, | |
389 | DEFAULT_TYPE => '$args{DEFAULT_TYPE}', | |
390 | EOT | |
391 | foreach (qw (C_FILE XS_FILE)) { | |
392 | next unless exists $args{$_}; | |
393 | $result .= sprintf " %-12s => '%s',\n", | |
394 | $_, $args{$_}; | |
395 | } | |
396 | $result .= <<'EOT'; | |
397 | ); | |
398 | EOT | |
399 | ||
400 | $result =~ s/^/' 'x$indent/gem; | |
401 | return ExtUtils::Constant::XS->dump_names({default_type=>$args{DEFAULT_TYPE}, | |
402 | indent=>$indent,}, | |
403 | @{$args{NAMES}}) | |
404 | . $result; | |
405 | } | |
406 | ||
407 | =item WriteConstants ATTRIBUTE =E<gt> VALUE [, ...] | |
408 | ||
409 | Writes a file of C code and a file of XS code which you should C<#include> | |
410 | and C<INCLUDE> in the C and XS sections respectively of your module's XS | |
411 | code. You probably want to do this in your C<Makefile.PL>, so that you can | |
412 | easily edit the list of constants without touching the rest of your module. | |
413 | The attributes supported are | |
414 | ||
415 | =over 4 | |
416 | ||
417 | =item NAME | |
418 | ||
419 | Name of the module. This must be specified | |
420 | ||
421 | =item DEFAULT_TYPE | |
422 | ||
423 | The default type for the constants. If not specified C<IV> is assumed. | |
424 | ||
425 | =item BREAKOUT_AT | |
426 | ||
427 | The names of the constants are grouped by length. Generate child subroutines | |
428 | for each group with this number or more names in. | |
429 | ||
430 | =item NAMES | |
431 | ||
432 | An array of constants' names, either scalars containing names, or hashrefs | |
433 | as detailed in L<"C_constant">. | |
434 | ||
435 | =item C_FILE | |
436 | ||
437 | The name of the file to write containing the C code. The default is | |
438 | C<const-c.inc>. The C<-> in the name ensures that the file can't be | |
439 | mistaken for anything related to a legitimate perl package name, and | |
440 | not naming the file C<.c> avoids having to override Makefile.PL's | |
441 | C<.xs> to C<.c> rules. | |
442 | ||
443 | =item XS_FILE | |
444 | ||
445 | The name of the file to write containing the XS code. The default is | |
446 | C<const-xs.inc>. | |
447 | ||
448 | =item SUBNAME | |
449 | ||
450 | The perl visible name of the XS subroutine generated which will return the | |
451 | constants. The default is C<constant>. | |
452 | ||
453 | =item C_SUBNAME | |
454 | ||
455 | The name of the C subroutine generated which will return the constants. | |
456 | The default is I<SUBNAME>. Child subroutines have C<_> and the name | |
457 | length appended, so constants with 10 character names would be in | |
458 | C<constant_10> with the default I<XS_SUBNAME>. | |
459 | ||
460 | =back | |
461 | ||
462 | =cut | |
463 | ||
464 | sub WriteConstants { | |
465 | my %ARGS = | |
466 | ( # defaults | |
467 | C_FILE => 'const-c.inc', | |
468 | XS_FILE => 'const-xs.inc', | |
469 | SUBNAME => 'constant', | |
470 | DEFAULT_TYPE => 'IV', | |
471 | @_); | |
472 | ||
473 | $ARGS{C_SUBNAME} ||= $ARGS{SUBNAME}; # No-one sane will have C_SUBNAME eq '0' | |
474 | ||
475 | croak "Module name not specified" unless length $ARGS{NAME}; | |
476 | ||
477 | my ($c_fh, $xs_fh); | |
478 | if ($] <= 5.008) { | |
479 | # We need these little games, rather than doing things unconditionally, | |
480 | # because we're used in core Makefile.PLs before IO is available (needed | |
481 | # by filehandle), but also we want to work on older perls where undefined | |
482 | # scalars do not automatically turn into anonymous file handles. | |
483 | require FileHandle; | |
484 | $c_fh = FileHandle->new(); | |
485 | $xs_fh = FileHandle->new(); | |
486 | } | |
487 | open $c_fh, ">$ARGS{C_FILE}" or die "Can't open $ARGS{C_FILE}: $!"; | |
488 | open $xs_fh, ">$ARGS{XS_FILE}" or die "Can't open $ARGS{XS_FILE}: $!"; | |
489 | ||
490 | # As this subroutine is intended to make code that isn't edited, there's no | |
491 | # need for the user to specify any types that aren't found in the list of | |
492 | # names. | |
493 | my $types = {}; | |
494 | ||
495 | print $c_fh constant_types(); # macro defs | |
496 | print $c_fh "\n"; | |
497 | ||
498 | # indent is still undef. Until anyone implements indent style rules with it. | |
499 | foreach (ExtUtils::Constant::XS->C_constant({package => $ARGS{NAME}, | |
500 | subname => $ARGS{C_SUBNAME}, | |
501 | default_type => | |
502 | $ARGS{DEFAULT_TYPE}, | |
503 | types => $types, | |
504 | breakout => $ARGS{BREAKOUT_AT}}, | |
505 | @{$ARGS{NAMES}})) { | |
506 | print $c_fh $_, "\n"; # C constant subs | |
507 | } | |
508 | print $xs_fh XS_constant ($ARGS{NAME}, $types, $ARGS{XS_SUBNAME}, | |
509 | $ARGS{C_SUBNAME}); | |
510 | ||
511 | close $c_fh or warn "Error closing $ARGS{C_FILE}: $!"; | |
512 | close $xs_fh or warn "Error closing $ARGS{XS_FILE}: $!"; | |
513 | } | |
514 | ||
515 | 1; | |
516 | __END__ | |
517 | ||
518 | =back | |
519 | ||
520 | =head1 AUTHOR | |
521 | ||
522 | Nicholas Clark <nick@ccl4.org> based on the code in C<h2xs> by Larry Wall and | |
523 | others | |
524 | ||
525 | =cut |