diff options
author | Siep Kroonenberg <siepo@cybercomm.nl> | 2011-02-17 16:52:23 +0000 |
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committer | Siep Kroonenberg <siepo@cybercomm.nl> | 2011-02-17 16:52:23 +0000 |
commit | 8da2d23733595367fad869e5fbc6c9a87041879b (patch) | |
tree | 0f3719f4eea97f872b6347c6d9ff5aa2ccd38299 /Master/tlpkg/tlperl/lib/XSLoader.pm | |
parent | 9d55a4cf517a832c74e85179eac4239f9be8d2e7 (diff) |
New tlperl part VIII
git-svn-id: svn://tug.org/texlive/trunk@21430 c570f23f-e606-0410-a88d-b1316a301751
Diffstat (limited to 'Master/tlpkg/tlperl/lib/XSLoader.pm')
-rw-r--r-- | Master/tlpkg/tlperl/lib/XSLoader.pm | 358 |
1 files changed, 358 insertions, 0 deletions
diff --git a/Master/tlpkg/tlperl/lib/XSLoader.pm b/Master/tlpkg/tlperl/lib/XSLoader.pm new file mode 100644 index 00000000000..98ed299d8b3 --- /dev/null +++ b/Master/tlpkg/tlperl/lib/XSLoader.pm @@ -0,0 +1,358 @@ +# Generated from XSLoader.pm.PL (resolved %Config::Config value) + +package XSLoader; + +$VERSION = "0.10"; + +#use strict; + +# enable debug/trace messages from DynaLoader perl code +# $dl_debug = $ENV{PERL_DL_DEBUG} || 0 unless defined $dl_debug; + + my $dl_dlext = 'dll'; + +package DynaLoader; + +# No prizes for guessing why we don't say 'bootstrap DynaLoader;' here. +# NOTE: All dl_*.xs (including dl_none.xs) define a dl_error() XSUB +boot_DynaLoader('DynaLoader') if defined(&boot_DynaLoader) && + !defined(&dl_error); +package XSLoader; + +sub load { + package DynaLoader; + + die q{XSLoader::load('Your::Module', $Your::Module::VERSION)} unless @_; + + my($module) = $_[0]; + + # work with static linking too + my $boots = "$module\::bootstrap"; + goto &$boots if defined &$boots; + + goto retry unless $module and defined &dl_load_file; + + my @modparts = split(/::/,$module); + my $modfname = $modparts[-1]; + + my $modpname = join('/',@modparts); + my $modlibname = (caller())[1]; + my $c = @modparts; + $modlibname =~ s,[\\/][^\\/]+$,, while $c--; # Q&D basename + my $file = "$modlibname/auto/$modpname/$modfname.$dl_dlext"; + +# print STDERR "XSLoader::load for $module ($file)\n" if $dl_debug; + + my $bs = $file; + $bs =~ s/(\.\w+)?(;\d*)?$/\.bs/; # look for .bs 'beside' the library + + if (-s $bs) { # only read file if it's not empty +# print STDERR "BS: $bs ($^O, $dlsrc)\n" if $dl_debug; + eval { do $bs; }; + warn "$bs: $@\n" if $@; + } + + goto retry if not -f $file or -s $bs; + + my $bootname = "boot_$module"; + $bootname =~ s/\W/_/g; + @DynaLoader::dl_require_symbols = ($bootname); + + my $boot_symbol_ref; + + # Many dynamic extension loading problems will appear to come from + # this section of code: XYZ failed at line 123 of DynaLoader.pm. + # Often these errors are actually occurring in the initialisation + # C code of the extension XS file. Perl reports the error as being + # in this perl code simply because this was the last perl code + # it executed. + + my $libref = dl_load_file($file, 0) or do { + require Carp; + Carp::croak("Can't load '$file' for module $module: " . dl_error()); + }; + push(@DynaLoader::dl_librefs,$libref); # record loaded object + + my @unresolved = dl_undef_symbols(); + if (@unresolved) { + require Carp; + Carp::carp("Undefined symbols present after loading $file: @unresolved\n"); + } + + $boot_symbol_ref = dl_find_symbol($libref, $bootname) or do { + require Carp; + Carp::croak("Can't find '$bootname' symbol in $file\n"); + }; + + push(@DynaLoader::dl_modules, $module); # record loaded module + + boot: + my $xs = dl_install_xsub($boots, $boot_symbol_ref, $file); + + # See comment block above + push(@DynaLoader::dl_shared_objects, $file); # record files loaded + return &$xs(@_); + + retry: + my $bootstrap_inherit = DynaLoader->can('bootstrap_inherit') || + XSLoader->can('bootstrap_inherit'); + goto &$bootstrap_inherit; +} + +# Versions of DynaLoader prior to 5.6.0 don't have this function. +sub bootstrap_inherit { + package DynaLoader; + + my $module = $_[0]; + local *DynaLoader::isa = *{"$module\::ISA"}; + local @DynaLoader::isa = (@DynaLoader::isa, 'DynaLoader'); + # Cannot goto due to delocalization. Will report errors on a wrong line? + require DynaLoader; + DynaLoader::bootstrap(@_); +} + +1; + + +__END__ + +=head1 NAME + +XSLoader - Dynamically load C libraries into Perl code + +=head1 VERSION + +Version 0.10 + +=head1 SYNOPSIS + + package YourPackage; + use XSLoader; + + XSLoader::load 'YourPackage', $YourPackage::VERSION; + +=head1 DESCRIPTION + +This module defines a standard I<simplified> interface to the dynamic +linking mechanisms available on many platforms. Its primary purpose is +to implement cheap automatic dynamic loading of Perl modules. + +For a more complicated interface, see L<DynaLoader>. Many (most) +features of C<DynaLoader> are not implemented in C<XSLoader>, like for +example the C<dl_load_flags>, not honored by C<XSLoader>. + +=head2 Migration from C<DynaLoader> + +A typical module using L<DynaLoader|DynaLoader> starts like this: + + package YourPackage; + require DynaLoader; + + our @ISA = qw( OnePackage OtherPackage DynaLoader ); + our $VERSION = '0.01'; + bootstrap YourPackage $VERSION; + +Change this to + + package YourPackage; + use XSLoader; + + our @ISA = qw( OnePackage OtherPackage ); + our $VERSION = '0.01'; + XSLoader::load 'YourPackage', $VERSION; + +In other words: replace C<require DynaLoader> by C<use XSLoader>, remove +C<DynaLoader> from C<@ISA>, change C<bootstrap> by C<XSLoader::load>. Do not +forget to quote the name of your package on the C<XSLoader::load> line, +and add comma (C<,>) before the arguments (C<$VERSION> above). + +Of course, if C<@ISA> contained only C<DynaLoader>, there is no need to have +the C<@ISA> assignment at all; moreover, if instead of C<our> one uses the +more backward-compatible + + use vars qw($VERSION @ISA); + +one can remove this reference to C<@ISA> together with the C<@ISA> assignment. + +If no C<$VERSION> was specified on the C<bootstrap> line, the last line becomes + + XSLoader::load 'YourPackage'; + +=head2 Backward compatible boilerplate + +If you want to have your cake and eat it too, you need a more complicated +boilerplate. + + package YourPackage; + use vars qw($VERSION @ISA); + + @ISA = qw( OnePackage OtherPackage ); + $VERSION = '0.01'; + eval { + require XSLoader; + XSLoader::load('YourPackage', $VERSION); + 1; + } or do { + require DynaLoader; + push @ISA, 'DynaLoader'; + bootstrap YourPackage $VERSION; + }; + +The parentheses about C<XSLoader::load()> arguments are needed since we replaced +C<use XSLoader> by C<require>, so the compiler does not know that a function +C<XSLoader::load()> is present. + +This boilerplate uses the low-overhead C<XSLoader> if present; if used with +an antic Perl which has no C<XSLoader>, it falls back to using C<DynaLoader>. + +=head1 Order of initialization: early load() + +I<Skip this section if the XSUB functions are supposed to be called from other +modules only; read it only if you call your XSUBs from the code in your module, +or have a C<BOOT:> section in your XS file (see L<perlxs/"The BOOT: Keyword">). +What is described here is equally applicable to the L<DynaLoader|DynaLoader> +interface.> + +A sufficiently complicated module using XS would have both Perl code (defined +in F<YourPackage.pm>) and XS code (defined in F<YourPackage.xs>). If this +Perl code makes calls into this XS code, and/or this XS code makes calls to +the Perl code, one should be careful with the order of initialization. + +The call to C<XSLoader::load()> (or C<bootstrap()>) has three side effects: + +=over + +=item * + +if C<$VERSION> was specified, a sanity check is done to ensure that the +versions of the F<.pm> and the (compiled) F<.xs> parts are compatible; + +=item * + +the XSUBs are made accessible from Perl; + +=item * + +if a C<BOOT:> section was present in the F<.xs> file, the code there is called. + +=back + +Consequently, if the code in the F<.pm> file makes calls to these XSUBs, it is +convenient to have XSUBs installed before the Perl code is defined; for +example, this makes prototypes for XSUBs visible to this Perl code. +Alternatively, if the C<BOOT:> section makes calls to Perl functions (or +uses Perl variables) defined in the F<.pm> file, they must be defined prior to +the call to C<XSLoader::load()> (or C<bootstrap()>). + +The first situation being much more frequent, it makes sense to rewrite the +boilerplate as + + package YourPackage; + use XSLoader; + use vars qw($VERSION @ISA); + + BEGIN { + @ISA = qw( OnePackage OtherPackage ); + $VERSION = '0.01'; + + # Put Perl code used in the BOOT: section here + + XSLoader::load 'YourPackage', $VERSION; + } + + # Put Perl code making calls into XSUBs here + +=head2 The most hairy case + +If the interdependence of your C<BOOT:> section and Perl code is +more complicated than this (e.g., the C<BOOT:> section makes calls to Perl +functions which make calls to XSUBs with prototypes), get rid of the C<BOOT:> +section altogether. Replace it with a function C<onBOOT()>, and call it like +this: + + package YourPackage; + use XSLoader; + use vars qw($VERSION @ISA); + + BEGIN { + @ISA = qw( OnePackage OtherPackage ); + $VERSION = '0.01'; + XSLoader::load 'YourPackage', $VERSION; + } + + # Put Perl code used in onBOOT() function here; calls to XSUBs are + # prototype-checked. + + onBOOT; + + # Put Perl initialization code assuming that XS is initialized here + + +=head1 DIAGNOSTICS + +=over + +=item C<Can't find '%s' symbol in %s> + +B<(F)> The bootstrap symbol could not be found in the extension module. + +=item C<Can't load '%s' for module %s: %s> + +B<(F)> The loading or initialisation of the extension module failed. +The detailed error follows. + +=item C<Undefined symbols present after loading %s: %s> + +B<(W)> As the message says, some symbols stay undefined although the +extension module was correctly loaded and initialised. The list of undefined +symbols follows. + +=item C<XSLoader::load('Your::Module', $Your::Module::VERSION)> + +B<(F)> You tried to invoke C<load()> without any argument. You must supply +a module name, and optionally its version. + +=back + + +=head1 LIMITATIONS + +To reduce the overhead as much as possible, only one possible location +is checked to find the extension DLL (this location is where C<make install> +would put the DLL). If not found, the search for the DLL is transparently +delegated to C<DynaLoader>, which looks for the DLL along the C<@INC> list. + +In particular, this is applicable to the structure of C<@INC> used for testing +not-yet-installed extensions. This means that running uninstalled extensions +may have much more overhead than running the same extensions after +C<make install>. + + +=head1 BUGS + +Please report any bugs or feature requests via the perlbug(1) utility. + + +=head1 SEE ALSO + +L<DynaLoader> + + +=head1 AUTHORS + +Ilya Zakharevich originally extracted C<XSLoader> from C<DynaLoader>. + +CPAN version is currently maintained by SE<eacute>bastien Aperghis-Tramoni +E<lt>sebastien@aperghis.netE<gt>. + +Previous maintainer was Michael G Schwern <schwern@pobox.com>. + + +=head1 COPYRIGHT & LICENSE + +Copyright (C) 1990-2007 by Larry Wall and others. + +This program is free software; you can redistribute it and/or modify +it under the same terms as Perl itself. + +=cut |