path: root/ext/Devel/PPPort/PPPort.pm

package Devel::PPPort;

=head1 NAME

Perl/Pollution/Portability

=head1 SYNOPSIS

    Devel::PPPort::WriteFile() ; # defaults to ./ppport.h
    Devel::PPPort::WriteFile('someheader.h') ;

=head1 DESCRIPTION

Perl has changed over time, gaining new features, new functions,
increasing its flexibility, and reducing the impact on the C namespace
environment (reduced pollution). The header file, typicaly C<ppport.h>,
written by this module attempts to bring some of the newer Perl
features to older versions of Perl, so that you can worry less about
keeping track of old releases, but users can still reap the benefit.
 
Why you should use C<ppport.h> in modern code: so that your code will work
with the widest range of Perl interpreters possible, without significant
additional work.

Why you should attempt older code to fully use C<ppport.h>: because
the reduced pollution of newer Perl versions is an important thing, so
important that the old polluting ways of original Perl modules will not be
supported very far into the future, and your module will almost certainly
break! By adapting to it now, you'll gained compatibility and a sense of
having done the electronic ecology some good.

How to use ppport.h: Don't direct the user to download C<Devel::PPPort>,
and don't make C<ppport.h> optional. Rather, just take the most recent
copy of C<ppport.h> that you can find (probably in C<Devel::PPPort>
on CPAN), copy it into your project, adjust your project to use it,
and distribute the header along with your module.

C<Devel::PPPort> contains a single function, called C<WriteFile>. It's
purpose is to write a 'C' header file that is used when writing XS
modules. The file contains a series of macros that allow XS modules to
be built using older versions of Perl.

This module is used by h2xs to write the file F<ppport.h>. 

=head2 WriteFile

C<WriteFile> takes a zero or one parameters. When called with one
parameter it expects to be passed a filename. When called with no
parameters, it defults to the filename C<./pport.h>.

The function returns TRUE if the file was written successfully. Otherwise
it returns FALSE.

=head1 ppport.h

The file written by this module, typically C<ppport.h>, provides access
to the following Perl API if not already available:

    DEFSV
    ERRSV
    INT2PTR(any,d)
    MY_CXT
    MY_CXT_INIT
    NOOP
    PERL_REVISION
    PERL_SUBVERSION
    PERL_UNUSED_DECL
    PERL_VERSION
    PL_Sv
    PL_compiling
    PL_copline
    PL_curcop
    PL_curstash
    PL_defgv
    PL_dirty
    PL_hints
    PL_na
    PL_perldb
    PL_rsfp_filters
    PL_rsfpv
    PL_stdingv
    PL_sv_no
    PL_sv_undef
    PL_sv_yes
    PTR2IV(d)
    SAVE_DEFSV
    START_MY_CXT
    _aMY_CXT
    _pMY_CXT
    aMY_CXT
    aMY_CXT_
    aTHX
    aTHX_
    boolSV(b)
    dMY_CXT	
    dMY_CXT_SV
    dNOOP
    dTHR
    gv_stashpvn(str,len,flags)
    newCONSTSUB(stash,name,sv)
    newRV_inc(sv)
    newRV_noinc(sv)
    newSVpvn(data,len)
    pMY_CXT
    pMY_CXT_
    pTHX
    pTHX_

=head1 AUTHOR

Version 1.x of Devel::PPPort was written by Kenneth Albanowski.

Version 2.x was ported to the Perl core by Paul Marquess.

=head1 SEE ALSO

See L<h2xs>.

=cut


package Devel::PPPort;

require Exporter;
require DynaLoader;
#use warnings;
use strict;
use vars qw( $VERSION @ISA @EXPORT @EXPORT_OK $data );

$VERSION = "2.0002";

@ISA = qw(Exporter DynaLoader);
@EXPORT =  qw();
# Other items we are prepared to export if requested
@EXPORT_OK = qw( );

bootstrap Devel::PPPort;

package Devel::PPPort;

{
    local $/ = undef;
    $data = <DATA> ;
    my $now = localtime;
    my $pkg = __PACKAGE__;
    $data =~ s/__VERSION__/$VERSION/g;
    $data =~ s/__DATE__/$now/g;
    $data =~ s/__PKG__/$pkg/g;
}

sub WriteFile
{
    my $file = shift || 'ppport.h' ;

    open F, ">$file" || return undef ;
    print F $data ;
    close F;

    return 1 ;
}

1;

__DATA__;

/* ppport.h -- Perl/Pollution/Portability Version __VERSION__ 
 *
 * Automatically Created by __PKG__ on __DATE__ 
 *
 * Do NOT edit this file directly! -- Edit PPPort.pm instead.
 *
 * Version 2.x, Copyright (C) 2001, Paul Marquess.
 * Version 1.x, Copyright (C) 1999, Kenneth Albanowski.
 * This code may be used and distributed under the same license as any
 * version of Perl.
 * 
 * This version of ppport.h is designed to support operation with Perl
 * installations back to 5.004, and has been tested up to 5.8.0.
 *
 * If this version of ppport.h is failing during the compilation of this
 * module, please check if a newer version of Devel::PPPort is available
 * on CPAN before sending a bug report.
 *
 * If you are using the latest version of Devel::PPPort and it is failing
 * during compilation of this module, please send a report to perlbug@perl.com
 *
 * Include all following information:
 *
 *  1. The complete output from running "perl -V"
 *
 *  2. This file.
 *
 *  3. The name & version of the module you were trying to build.
 *
 *  4. A full log of the build that failed.
 *
 *  5. Any other information that you think could be relevant.
 *
 *
 * For the latest version of this code, please retreive the Devel::PPPort
 * module from CPAN.
 * 
 */

/*
 * In order for a Perl extension module to be as portable as possible
 * across differing versions of Perl itself, certain steps need to be taken.
 * Including this header is the first major one, then using dTHR is all the
 * appropriate places and using a PL_ prefix to refer to global Perl
 * variables is the second.
 *
 */


/* If you use one of a few functions that were not present in earlier
 * versions of Perl, please add a define before the inclusion of ppport.h
 * for a static include, or use the GLOBAL request in a single module to
 * produce a global definition that can be referenced from the other
 * modules.
 * 
 * Function:            Static define:           Extern define:
 * newCONSTSUB()        NEED_newCONSTSUB         NEED_newCONSTSUB_GLOBAL
 *
 */
 

/* To verify whether ppport.h is needed for your module, and whether any
 * special defines should be used, ppport.h can be run through Perl to check
 * your source code. Simply say:
 * 
 * 	perl -x ppport.h *.c *.h *.xs foo/bar*.c [etc]
 * 
 * The result will be a list of patches suggesting changes that should at
 * least be acceptable, if not necessarily the most efficient solution, or a
 * fix for all possible problems. It won't catch where dTHR is needed, and
 * doesn't attempt to account for global macro or function definitions,
 * nested includes, typemaps, etc.
 * 
 * In order to test for the need of dTHR, please try your module under a
 * recent version of Perl that has threading compiled-in.
 *
 */ 


/*
#!/usr/bin/perl
@ARGV = ("*.xs") if !@ARGV;
%badmacros = %funcs = %macros = (); $replace = 0;
foreach (<DATA>) {
	$funcs{$1} = 1 if /Provide:\s+(\S+)/;
	$macros{$1} = 1 if /^#\s*define\s+([a-zA-Z0-9_]+)/;
	$replace = $1 if /Replace:\s+(\d+)/;
	$badmacros{$2}=$1 if $replace and /^#\s*define\s+([a-zA-Z0-9_]+).*?\s+([a-zA-Z0-9_]+)/;
	$badmacros{$1}=$2 if /Replace (\S+) with (\S+)/;
}
foreach $filename (map(glob($_),@ARGV)) {
	unless (open(IN, "<$filename")) {
		warn "Unable to read from $file: $!\n";
		next;
	}
	print "Scanning $filename...\n";
	$c = ""; while (<IN>) { $c .= $_; } close(IN);
	$need_include = 0; %add_func = (); $changes = 0;
	$has_include = ($c =~ /#.*include.*ppport/m);

	foreach $func (keys %funcs) {
		if ($c =~ /#.*define.*\bNEED_$func(_GLOBAL)?\b/m) {
			if ($c !~ /\b$func\b/m) {
				print "If $func isn't needed, you don't need to request it.\n" if
				$changes += ($c =~ s/^.*#.*define.*\bNEED_$func\b.*\n//m);
			} else {
				print "Uses $func\n";
				$need_include = 1;
			}
		} else {
			if ($c =~ /\b$func\b/m) {
				$add_func{$func} =1 ;
				print "Uses $func\n";
				$need_include = 1;
			}
		}
	}

	if (not $need_include) {
		foreach $macro (keys %macros) {
			if ($c =~ /\b$macro\b/m) {
				print "Uses $macro\n";
				$need_include = 1;
			}
		}
	}

	foreach $badmacro (keys %badmacros) {
		if ($c =~ /\b$badmacro\b/m) {
			$changes += ($c =~ s/\b$badmacro\b/$badmacros{$badmacro}/gm);
			print "Uses $badmacros{$badmacro} (instead of $badmacro)\n";
			$need_include = 1;
		}
	}
	
	if (scalar(keys %add_func) or $need_include != $has_include) {
		if (!$has_include) {
			$inc = join('',map("#define NEED_$_\n", sort keys %add_func)).
			       "#include \"ppport.h\"\n";
			$c = "$inc$c" unless $c =~ s/#.*include.*XSUB.*\n/$&$inc/m;
		} elsif (keys %add_func) {
			$inc = join('',map("#define NEED_$_\n", sort keys %add_func));
			$c = "$inc$c" unless $c =~ s/^.*#.*include.*ppport.*$/$inc$&/m;
		}
		if (!$need_include) {
			print "Doesn't seem to need ppport.h.\n";
			$c =~ s/^.*#.*include.*ppport.*\n//m;
		}
		$changes++;
	}
	
	if ($changes) {
		open(OUT,">/tmp/ppport.h.$$");
		print OUT $c;
		close(OUT);
		open(DIFF, "diff -u $filename /tmp/ppport.h.$$|");
		while (<DIFF>) { s!/tmp/ppport\.h\.$$!$filename.patched!; print STDOUT; }
		close(DIFF);
		unlink("/tmp/ppport.h.$$");
	} else {
		print "Looks OK\n";
	}
}
__DATA__
*/

#ifndef _P_P_PORTABILITY_H_
#define _P_P_PORTABILITY_H_

#ifndef PERL_REVISION
#   ifndef __PATCHLEVEL_H_INCLUDED__
#       include "patchlevel.h"
#   endif
#   ifndef PERL_REVISION
#	define PERL_REVISION	(5)
        /* Replace: 1 */
#       define PERL_VERSION	PATCHLEVEL
#       define PERL_SUBVERSION	SUBVERSION
        /* Replace PERL_PATCHLEVEL with PERL_VERSION */
        /* Replace: 0 */
#   endif
#endif

#define PERL_BCDVERSION ((PERL_REVISION * 0x1000000L) + (PERL_VERSION * 0x1000L) + PERL_SUBVERSION)

/* It is very unlikely that anyone will try to use this with Perl 6 
   (or greater), but who knows.
 */
#if PERL_REVISION != 5
#	error ppport.h only works with Perl version 5
#endif /* PERL_REVISION != 5 */

#ifndef ERRSV
#	define ERRSV perl_get_sv("@",FALSE)
#endif

#if (PERL_VERSION < 4) || ((PERL_VERSION == 4) && (PERL_SUBVERSION <= 5))
/* Replace: 1 */
#	define PL_Sv		Sv
#	define PL_compiling	compiling
#	define PL_copline	copline
#	define PL_curcop	curcop
#	define PL_curstash	curstash
#	define PL_defgv		defgv
#	define PL_dirty		dirty
#	define PL_dowarn	dowarn
#	define PL_hints		hints
#	define PL_na		na
#	define PL_perldb	perldb
#	define PL_rsfp_filters	rsfp_filters
#	define PL_rsfpv		rsfp
#	define PL_stdingv	stdingv
#	define PL_sv_no		sv_no
#	define PL_sv_undef	sv_undef
#	define PL_sv_yes	sv_yes
/* Replace: 0 */
#endif

#ifdef HASATTRIBUTE
#  if defined(__GNUC__) && defined(__cplusplus)
#    define PERL_UNUSED_DECL
#  else
#    define PERL_UNUSED_DECL __attribute__((unused))
#  endif
#else
#  define PERL_UNUSED_DECL
#endif

#ifndef dNOOP
#  define NOOP (void)0
#  define dNOOP extern int Perl___notused PERL_UNUSED_DECL
#endif

#ifndef dTHR
#  define dTHR          dNOOP
#endif

#ifndef dTHX
#  define dTHX          dNOOP
#  define dTHXa(x)      dNOOP
#  define dTHXoa(x)     dNOOP
#endif

#ifndef pTHX
#    define pTHX	void
#    define pTHX_
#    define aTHX
#    define aTHX_
#endif         

#ifndef PTR2IV
#    define PTR2IV(d)   (IV)(d)
#endif
 
#ifndef INT2PTR
#    define INT2PTR(any,d)      (any)(d)
#endif

#ifndef boolSV
#	define boolSV(b) ((b) ? &PL_sv_yes : &PL_sv_no)
#endif

#ifndef gv_stashpvn
#	define gv_stashpvn(str,len,flags) gv_stashpv(str,flags)
#endif

#ifndef newSVpvn
#	define newSVpvn(data,len) ((len) ? newSVpv ((data), (len)) : newSVpv ("", 0))
#endif

#ifndef newRV_inc
/* Replace: 1 */
#	define newRV_inc(sv) newRV(sv)
/* Replace: 0 */
#endif

/* DEFSV appears first in 5.004_56 */
#ifndef DEFSV
#  define DEFSV	GvSV(PL_defgv)
#endif

#ifndef SAVE_DEFSV
#    define SAVE_DEFSV SAVESPTR(GvSV(PL_defgv))
#endif

#ifndef newRV_noinc
#  ifdef __GNUC__
#    define newRV_noinc(sv)               \
      ({                                  \
          SV *nsv = (SV*)newRV(sv);       \
          SvREFCNT_dec(sv);               \
          nsv;                            \
      })
#  else
#    if defined(USE_THREADS)
static SV * newRV_noinc (SV * sv)
{
          SV *nsv = (SV*)newRV(sv);       
          SvREFCNT_dec(sv);               
          return nsv;                     
}
#    else
#      define newRV_noinc(sv)    \
        (PL_Sv=(SV*)newRV(sv), SvREFCNT_dec(sv), (SV*)PL_Sv)
#    endif
#  endif
#endif

/* Provide: newCONSTSUB */

/* newCONSTSUB from IO.xs is in the core starting with 5.004_63 */
#if (PERL_VERSION < 4) || ((PERL_VERSION == 4) && (PERL_SUBVERSION < 63))

#if defined(NEED_newCONSTSUB)
static
#else
extern void newCONSTSUB(HV * stash, char * name, SV *sv);
#endif

#if defined(NEED_newCONSTSUB) || defined(NEED_newCONSTSUB_GLOBAL)
void
newCONSTSUB(stash,name,sv)
HV *stash;
char *name;
SV *sv;
{
	U32 oldhints = PL_hints;
	HV *old_cop_stash = PL_curcop->cop_stash;
	HV *old_curstash = PL_curstash;
	line_t oldline = PL_curcop->cop_line;
	PL_curcop->cop_line = PL_copline;

	PL_hints &= ~HINT_BLOCK_SCOPE;
	if (stash)
		PL_curstash = PL_curcop->cop_stash = stash;

	newSUB(

#if (PERL_VERSION < 3) || ((PERL_VERSION == 3) && (PERL_SUBVERSION < 22))
     /* before 5.003_22 */
		start_subparse(),
#else
#  if (PERL_VERSION == 3) && (PERL_SUBVERSION == 22)
     /* 5.003_22 */
     		start_subparse(0),
#  else
     /* 5.003_23  onwards */
     		start_subparse(FALSE, 0),
#  endif
#endif

		newSVOP(OP_CONST, 0, newSVpv(name,0)),
		newSVOP(OP_CONST, 0, &PL_sv_no),   /* SvPV(&PL_sv_no) == "" -- GMB */
		newSTATEOP(0, Nullch, newSVOP(OP_CONST, 0, sv))
	);

	PL_hints = oldhints;
	PL_curcop->cop_stash = old_cop_stash;
	PL_curstash = old_curstash;
	PL_curcop->cop_line = oldline;
}
#endif

#endif /* newCONSTSUB */

#ifndef START_MY_CXT

/*
 * Boilerplate macros for initializing and accessing interpreter-local
 * data from C.  All statics in extensions should be reworked to use
 * this, if you want to make the extension thread-safe.  See ext/re/re.xs
 * for an example of the use of these macros.
 *
 * Code that uses these macros is responsible for the following:
 * 1. #define MY_CXT_KEY to a unique string, e.g. "DynaLoader_guts"
 * 2. Declare a typedef named my_cxt_t that is a structure that contains
 *    all the data that needs to be interpreter-local.
 * 3. Use the START_MY_CXT macro after the declaration of my_cxt_t.
 * 4. Use the MY_CXT_INIT macro such that it is called exactly once
 *    (typically put in the BOOT: section).
 * 5. Use the members of the my_cxt_t structure everywhere as
 *    MY_CXT.member.
 * 6. Use the dMY_CXT macro (a declaration) in all the functions that
 *    access MY_CXT.
 */

#if defined(MULTIPLICITY) || defined(PERL_OBJECT) || \
    defined(PERL_CAPI)    || defined(PERL_IMPLICIT_CONTEXT)

/* This must appear in all extensions that define a my_cxt_t structure,
 * right after the definition (i.e. at file scope).  The non-threads
 * case below uses it to declare the data as static. */
#define START_MY_CXT

#if (PERL_VERSION < 4 || (PERL_VERSION == 4 && PERL_SUBVERSION < 68 ))
/* Fetches the SV that keeps the per-interpreter data. */
#define dMY_CXT_SV \
	SV *my_cxt_sv = perl_get_sv(MY_CXT_KEY, FALSE)
#else /* >= perl5.004_68 */
#define dMY_CXT_SV \
	SV *my_cxt_sv = *hv_fetch(PL_modglobal, MY_CXT_KEY,		\
				  sizeof(MY_CXT_KEY)-1, TRUE)
#endif /* < perl5.004_68 */

/* This declaration should be used within all functions that use the
 * interpreter-local data. */
#define dMY_CXT	\
	dMY_CXT_SV;							\
	my_cxt_t *my_cxtp = INT2PTR(my_cxt_t*,SvUV(my_cxt_sv))

/* Creates and zeroes the per-interpreter data.
 * (We allocate my_cxtp in a Perl SV so that it will be released when
 * the interpreter goes away.) */
#define MY_CXT_INIT \
	dMY_CXT_SV;							\
	/* newSV() allocates one more than needed */			\
	my_cxt_t *my_cxtp = (my_cxt_t*)SvPVX(newSV(sizeof(my_cxt_t)-1));\
	Zero(my_cxtp, 1, my_cxt_t);					\
	sv_setuv(my_cxt_sv, PTR2UV(my_cxtp))

/* This macro must be used to access members of the my_cxt_t structure.
 * e.g. MYCXT.some_data */
#define MY_CXT		(*my_cxtp)

/* Judicious use of these macros can reduce the number of times dMY_CXT
 * is used.  Use is similar to pTHX, aTHX etc. */
#define pMY_CXT		my_cxt_t *my_cxtp
#define pMY_CXT_	pMY_CXT,
#define _pMY_CXT	,pMY_CXT
#define aMY_CXT		my_cxtp
#define aMY_CXT_	aMY_CXT,
#define _aMY_CXT	,aMY_CXT

#else /* single interpreter */


#define START_MY_CXT	static my_cxt_t my_cxt;
#define dMY_CXT_SV	dNOOP
#define dMY_CXT		dNOOP
#define MY_CXT_INIT	NOOP
#define MY_CXT		my_cxt

#define pMY_CXT		void
#define pMY_CXT_
#define _pMY_CXT
#define aMY_CXT
#define aMY_CXT_
#define _aMY_CXT

#endif 

#endif /* START_MY_CXT */

#endif /* _P_P_PORTABILITY_H_ */

/* End of File ppport.h */