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authorNorbert Preining <norbert@preining.info>2019-09-02 13:46:59 +0900
committerNorbert Preining <norbert@preining.info>2019-09-02 13:46:59 +0900
commite0c6872cf40896c7be36b11dcc744620f10adf1d (patch)
tree60335e10d2f4354b0674ec22d7b53f0f8abee672 /systems/texlive/tlnet/tlpkg/tlperl/lib/XSLoader.pm
Initial commit
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+# Generated from XSLoader_pm.PL (resolved %Config::Config value)
+# This file is unique for every OS
+
+package XSLoader;
+
+$VERSION = "0.30"; # remember to update version in POD!
+
+#use strict;
+
+package DynaLoader;
+
+# No prizes for guessing why we don't say 'bootstrap DynaLoader;' here.
+# NOTE: All dl_*.xs (including dl_none.xs) define a dl_error() XSUB
+boot_DynaLoader('DynaLoader') if defined(&boot_DynaLoader) &&
+ !defined(&dl_error);
+package XSLoader;
+
+sub load {
+ package DynaLoader;
+
+ my ($caller, $modlibname) = caller();
+ my $module = $caller;
+
+ if (@_) {
+ $module = $_[0];
+ } else {
+ $_[0] = $module;
+ }
+
+ # work with static linking too
+ my $boots = "$module\::bootstrap";
+ goto &$boots if defined &$boots;
+
+ goto \&XSLoader::bootstrap_inherit unless $module and defined &dl_load_file;
+
+ my @modparts = split(/::/,$module);
+ my $modfname = $modparts[-1];
+ my $modfname_orig = $modfname; # For .bs file search
+
+ my $modpname = join('/',@modparts);
+ my $c = () = split(/::/,$caller,-1);
+ $modlibname =~ s,[\\/][^\\/]+$,, while $c--; # Q&D basename
+ # Does this look like a relative path?
+ if ($modlibname !~ m{^(?:[A-Za-z]:)?[\\/]}) {
+ # Someone may have a #line directive that changes the file name, or
+ # may be calling XSLoader::load from inside a string eval. We cer-
+ # tainly do not want to go loading some code that is not in @INC,
+ # as it could be untrusted.
+ #
+ # We could just fall back to DynaLoader here, but then the rest of
+ # this function would go untested in the perl core, since all @INC
+ # paths are relative during testing. That would be a time bomb
+ # waiting to happen, since bugs could be introduced into the code.
+ #
+ # So look through @INC to see if $modlibname is in it. A rela-
+ # tive $modlibname is not a common occurrence, so this block is
+ # not hot code.
+ FOUND: {
+ for (@INC) {
+ if ($_ eq $modlibname) {
+ last FOUND;
+ }
+ }
+ # Not found. Fall back to DynaLoader.
+ goto \&XSLoader::bootstrap_inherit;
+ }
+ }
+ my $file = "$modlibname/auto/$modpname/$modfname.dll";
+
+# print STDERR "XSLoader::load for $module ($file)\n" if $dl_debug;
+
+ # N.B. The .bs file does not following the naming convention used
+ # by mod2fname, so use the unedited version of the name.
+
+ my $bs = "$modlibname/auto/$modpname/$modfname_orig.bs";
+
+ # This calls DynaLoader::bootstrap, which will load the .bs file if present
+ goto \&XSLoader::bootstrap_inherit 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
+
+ $boot_symbol_ref = dl_find_symbol($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(@_);
+}
+
+sub bootstrap_inherit {
+ require DynaLoader;
+ goto \&DynaLoader::bootstrap_inherit;
+}
+
+1;
+
+
+__END__
+
+=head1 NAME
+
+XSLoader - Dynamically load C libraries into Perl code
+
+=head1 VERSION
+
+Version 0.30
+
+=head1 SYNOPSIS
+
+ package YourPackage;
+ require XSLoader;
+
+ XSLoader::load(__PACKAGE__, $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 $VERSION = '0.01';
+ __PACKAGE__->bootstrap($VERSION);
+
+Change this to
+
+ package YourPackage;
+ use XSLoader;
+
+ our @ISA = qw( OnePackage OtherPackage );
+ our $VERSION = '0.01';
+ XSLoader::load(__PACKAGE__, $VERSION);
+
+In other words: replace C<require DynaLoader> by C<use XSLoader>, remove
+C<DynaLoader> from C<@ISA>, change C<bootstrap> by C<XSLoader::load>. Do not
+forget to quote the name of your package on the C<XSLoader::load> line,
+and add comma (C<,>) before the arguments (C<$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(__PACKAGE__);
+
+in which case it can be further simplified to
+
+ XSLoader::load();
+
+as C<load> will use C<caller> to determine the package.
+
+=head2 Backward compatible boilerplate
+
+If you want to have your cake and eat it too, you need a more complicated
+boilerplate.
+
+ package YourPackage;
+
+ our @ISA = qw( OnePackage OtherPackage );
+ our $VERSION = '0.01';
+ eval {
+ require XSLoader;
+ XSLoader::load(__PACKAGE__, $VERSION);
+ 1;
+ } or do {
+ require DynaLoader;
+ push @ISA, 'DynaLoader';
+ __PACKAGE__->bootstrap($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 antique 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()>) calls the module's
+bootstrap code. For modules build by F<xsubpp> (nearly all modules) this
+has three side effects:
+
+=over
+
+=item *
+
+A sanity check is done to ensure that the versions of the F<.pm> and the
+(compiled) F<.xs> parts are compatible. If C<$VERSION> was specified, this
+is used for the check. If not specified, it defaults to
+C<$XS_VERSION // $VERSION> (in the module's namespace)
+
+=item *
+
+the XSUBs are made accessible from Perl
+
+=item *
+
+if a C<BOOT:> section was present in the F<.xs> file, the code there is called.
+
+=back
+
+Consequently, if the code in the F<.pm> file makes calls to these XSUBs, it is
+convenient to have XSUBs installed before the Perl code is defined; for
+example, this makes prototypes for XSUBs visible to this Perl code.
+Alternatively, if the C<BOOT:> section makes calls to Perl functions (or
+uses Perl variables) defined in the F<.pm> file, they must be defined prior to
+the call to C<XSLoader::load()> (or C<bootstrap()>).
+
+The first situation being much more frequent, it makes sense to rewrite the
+boilerplate as
+
+ package YourPackage;
+ use XSLoader;
+ our ($VERSION, @ISA);
+
+ BEGIN {
+ @ISA = qw( OnePackage OtherPackage );
+ $VERSION = '0.01';
+
+ # Put Perl code used in the BOOT: section here
+
+ XSLoader::load(__PACKAGE__, $VERSION);
+ }
+
+ # Put Perl code making calls into XSUBs here
+
+=head2 The most hairy case
+
+If the interdependence of your C<BOOT:> section and Perl code is
+more complicated than this (e.g., the C<BOOT:> section makes calls to Perl
+functions which make calls to XSUBs with prototypes), get rid of the C<BOOT:>
+section altogether. Replace it with a function C<onBOOT()>, and call it like
+this:
+
+ package YourPackage;
+ use XSLoader;
+ our ($VERSION, @ISA);
+
+ BEGIN {
+ @ISA = qw( OnePackage OtherPackage );
+ $VERSION = '0.01';
+ XSLoader::load(__PACKAGE__, $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.
+
+=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 KNOWN BUGS
+
+The new simpler way to call C<XSLoader::load()> with no arguments at all
+does not work on Perl 5.8.4 and 5.8.5.
+
+
+=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) 1990-2011 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