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=head1 NAME

XS::Install - ExtUtils::MakeMaker based module installer for XS modules.

=head1 DESCRIPTION

To high-level overview please read L<Shared XS modules manifesto|XS::Manifesto>.

XS::Install (formerly known as L<Panda::Install>) makes it much easier to write MakeMaker's makefiles especially for XS modules.
It provides dependecies support between XS modules, so that one could easily use header files, code, compilation
options, ...etc of another. XS::Install also lets you put source files in subdirectories any level deep
(MakeMaker doesn't handle that) and easily compile-in external C libraries.

The params for XS::Install are compatible with MakeMaker with some additions.

Also it greatly extends typemap functionality and adds C-like XS synopsis.

=head1 SYNOPSIS

    # Makefile.PL
    use XS::Install;
    
    write_makefile(
        NAME    => 'My::XS',
        INC     => '-Isrc -I/usr/local/libevent/include',
        LIBS    => '-levent',
        SRC     => 'src', # all source files (code,header,xs) under 'src' are included in build
        C       => 'src2/foo.cc src2/bar.cc src3/baz/*.c', # plus src2/foo.cc, src2/bar.cc, and first-level c files in src3/baz/
        CPLUS   => 11,
        PAYLOAD => {
            # implements File::ShareDir functionality
            'data.txt'   => '/data.txt',
            'list.txt'   => '/',
            'abc.dat'    => '/mydir/bca.dat',
            'payloaddir' => '/',
        },
        BIN_DEPS  => ['XS::Module1', 'XS::Module2'],
        BIN_SHARE => {
            # modules that depend on My::XS will compile with this INC, LIBS, etc set.
            TYPEMAPS    => {'typemap1.map' => '/typemap.map'},
            INC         => '-I/usr/local/libevent/include', 
            INCLUDE     => {'src' => '/'},
            LIBS        => '-levent',
            DEFINE      => '-DHELLO_FROM_MYXS',
            CCFLAGS     => 'something',
        },
        postamble => 'mytarget: blah-blah; echo "hello"',
        CLIB => [{
            DIR    => 'libuv',
            FILE   => 'libuv.a',
            TARGET => 'libuv.a',
            FLAGS  => 'CFLAGS="-fPIC -O2"',
        }],
    );
    
=head1 LOADING XS MODULE SYNOPSIS

    package MyXSModule;
    use XS::Loader;
    
    our $VERSION = '1.0.0';
    XS::Loader::load(); # same as XS::Loader::load('MyXSModule', $VERSION, 0x01);
    
see L<XS::Loader>
    
=head1 C-LIKE XS SYNOPSIS

    #include <xs.h>

    char* my_xs_sub (SV* sv) { // CODE
        if (badsv(sv)) XSRETURN_UNDEF;
        RETVAL = process(sv);
    }
    
    void other_xs_sub (SV* sv) : ALIAS(other_name=1, yet_another=2) { // PPCODE
        xPUSHi(1);
        xPUSHi(2);
    }
    
=head1 GETTING PAYLOAD SYNOPSIS

    my $payload_dir = XS::Install::Payload::payload_dir('My::Module');
    
see L<XS::Install::Payload>

=head1 FUNCTIONS

=head4 write_makefile(%params)

Writes makefile

=head4 not_available($msg)

If called, Makefile.PL will die with your C<$msg> the way that CPAN testers will mark it as NA (not available) instead of UNKNOWN.

=head2 PARAMETERS

Only differences from MakeMaker params are listed.

=over 2

=item ALL_FROM [default: NAME]

Sets C<ABSTRACT_FROM> and C<VERSION_FROM> to value of C<ALL_FROM>.

=item VERSION_FROM [default: lib/Your/Package.pm]

If you don't specify C<VERSION_FROM>, the default is your main package file

=item ABSTRACT_FROM [default: lib/Your/Package.pod or lib/Your/Package.pm]

If you don't specify C<ABSTRACT_FROM>, the default is your main package pod file if it exists, otherwise main package file

=item XS [*.xs]

Sets source files for xsubpp. If you define this param, defaults are aborted.

    XS => 'myxs/*.xs'
    XS => 'file1.xs folder/file2.xs folder2/*.xs'
    XS => ['file1.xs', 'folder/file2.xs folder2/*.xs']

=item C [*.c, *.cc, *.cxx, *.cpp, <xsubpp's output files>]

Sets source files to compile. If you define this param, defaults are aborted, however C files created by xsubpp are
still included.

Usage: see "XS".

=item H [*.h *.hh *.hxx *.hpp]

Sets header files for makefile's dependencies (forces module to recompile if any of these changes). Useful during development.
If you define this param, defaults are aborted.

Usage: see "XS".

=item SRC

Scans specified folder(s), finds all XS, C and H files and includes them in build. No matter whether you define XS/C/H
parameters or not, SRCs are always added to them.

    SRC => 'src'
    SRC => 'src src2 src3',
    SRC => ['src src2', 'src3'],
    
=item CPLUS

If true, will use c++ to build current extension. Additionally, if > 1, will set -std=c++<CPLUS>
With this flag set, wraps every XSUB function into try-catch block, catching C++ exceptions and rethrowing it as perl exceptions.
Additionally, the default extension for XS files output becomes C<.cc> instead of C<.c>

=item OPTIMIZE [-O2]

Default is C<-O2>.
    
=item postamble

Passed unchanged to Makefile. Can be HASHREF for your convenience, in which case keys are ignored, values are concatenated
in undefined order. If it is important to keep the order, ARRAYREF can be supplied.

    postamble => 'sayhello: ; echo "hello"'
    postamble => {
        memd_dep   => 'linkext:: libmemd/libmemd.a; cd libmemd && $(MAKE) static',
        memd_clean => 'clean:: ; cd libmemd && $(MAKE) clean',
    }
    postamble => [
        'linkext:: libmemd/libmemd.a; cd libmemd && $(MAKE) static',
        'clean:: ; cd libmemd && $(MAKE) clean',
    ]

=item PARSE_XS

	PARSE_XS => 'XS::Framework::ParseXS'

Allows to inject custom ParseXS-plugin into xsubpp. As the module use on-the-fly patching of L<ExtUtils::ParseXS>
there is no sense of documenting it's internals, please, read the sources. Among the sources of L<XS::Framework>
you can find and example.

=item test/SRC

=item test/RECURSIVE_TEST_FILES

Sometimes XS-extension itself is written in C/C++, while XS/XSI files are only a thin perl-wrapper layer. In that
cases it is desirable to test C/C++ code independently, but using perl-testing infrastructure. C<XS::Install> 
does the trick: it compiles C/C++  test sources into additional XS-extension, and you should load it in perl
C<t>-files (see L<XS::Loader>).

The compiled test XS-extension is B<not> installed, and availale only during testing phase

    test     => {
        SRC                  => 't',
        RECURSIVE_TEST_FILES => 1,
    },

You still have to provide XS-file for the test extension. If you like to omit it and fond of 
L<Catch2|https://github.com/catchorg/Catch2> C++ module, then, please, familiarize yourself with L<Test::Catch>
module, which already provides all needed glue. To let C++ test work, there will be need:

	# t/some-file.t
	XS::Loader::load_noboot('MyTest');
	Test::Catch::run('[tag]');

	# t/some-file.cc
	#include <catch2/catch.hpp>
	TEST_CASE("description", "[tag]") {
		...
	}
	
=item test/CCFLAGS

Concatenated with C<CCFLAGS>, used when compiling test files.

=item test/OPTIMIZE

Concatenated with C<OPTIMIZE>, used when compiling test files. Default to <-O0> to decrease tests compilation time (performance of running
tests are usually affected by C<-O0> not really much).

=item MIN_PERL_VERSION [5.10.0]

Is set to 5.10.0 if you don't provide it.

=item PAYLOAD

Implements L<File::ShareDir> functionality. Specified files are installed together with module and can later be accessed
at runtime by the module itself or by other modules (via L<XS::Install::Payload>'s payload_dir()).

Value is a HASHREF where key is a file or directory path relative to module's dist dir and value is relative to payload's
installation dir. If key is a directory then all content of that directory is installed to the destination path. If value
is not specified (undef, '') then dest path is the same as source path.

Examples (given that $payload is a directory where payload is installed and $dist is a module's dist dir):

    'file.txt' => ''       # $dist/file.txt => $payload/file.txt
    'file.txt' => 'a.txt'  # $dist/file.txt => $payload/a.txt
    'mydir'    => '',      # $dist/mydir    => $payload/mydir
    'mydir'    => 'a/b/c', # $dist/mydir/*  => $payload/a/b/c/*
    'mydir'    => '/',     # $dist/mydir/*  => $payload/*

=item PKG_CONFIG

List of system packages current module depends on. They will be searched via L<PkgConfig> and their C<inc>, C<cflags> and C<ldflags> will be automatically added
to makefile. Also if your module has BIN_SHARE section then all packages in PKG_CONFIG goes to BIN_SHARE/PKG_CONFIG unless package name is prefixed
with '-' (minus).

Examples:

    PKG_CONFIG => 'openssl'
    PKG_CONFIG => ['libzip', '-libcap']

=item BIN_DEPS

List of modules current module binary depends on. That means all that those modules specified in BIN_SHARE section will be applied
while building current module. It also adds those modules to CONFIGURE_REQUIRES and PREREQ_PM sections.

Also if your module has BIN_SHARE section then all modules in BIN_DEPS goes to BIN_SHARE/PASSTHROUGH unless module name is prefixed
with '-' (minus).

Examples:

    BIN_DEPS => 'Module1'
    BIN_DEPS => ['Module1', '-Module2']

=item BIN_SHARE

In this section you put values that you want to be applied to any module which specified your module as a dependency.

=item BIN_SHARE/TYPEMAPS

Installs specified typemaps and also adds it to the list of typemaps when building descendant modules.

Receives HASHREF, format is the same as for PAYLOAD, the only difference is that it scans folders for *.map files only.

=item BIN_SHARE/INC

Adds include file dirs to INC when building descendant modules.

=item BIN_SHARE/INCLUDE

Installs specified include files/dirs into module's installation include directory and adds that directory to INC
when building descendant modules.

Receives HASHREF, format is the same as for PAYLOAD, the only difference is that it scans folders for header files only.

=item BIN_SHARE/LIBS

Added to LIBS when building descendant modules.

=item BIN_SHARE/DEFINE

Added to DEFINE when building descendant modules.

=item BIN_SHARE/CCFLAGS

Added to CCFLAGS when building descendant modules.

=item BIN_SHARE/XSOPT

Added to XSOPT when building descendant modules.

=item BIN_SHARE/PASSTHROUGH

Merge 'BIN_SHARE' of this module with 'BIN_SHARE' of specified modules. Everything gets concatenated (strings, arrays, etc) while merging.
You don't need to manually manage this setting as it's managed automatically (see BIN_DEPS section).

=item BIN_SHARE/CPLUS

If set to true, will use c++ when building descendant modules. If > 1, then will use this version -std=c++<CPLUS> for building descendant modules
(however if a descendant module sets its own CPLUS version then the highest version will be in use). Propagates all behaviour of C<CPLUS> for
descendant modules.

=item BIN_SHARE/PKG_CONFIG

All dependant modules will automatically get C<inc>, C<cflags> and C<ldflags> of these system packages

=item CLIB

List of external C libraries that need to be built and compiled into the extension.

=item CLIB/DIR

Directory where external library is. Makefile must present in that directory!

=item CLIB/FILE

Static library file which is built by the library (relative to CLIB/DIR).

=item CLIB/TARGET

Name of the target for Makefile to built static library.

=item CLIB/FLAGS

Flags to build external library with.

=back

=head1 C-LIKE XS

If you're using XS::Install then all of your XS files support C-like XS. It means that code
    
    char* my_xs_sub (SV* sv) { // CODE
        if (badsv(sv)) XSRETURN_UNDEF;
        RETVAL = process(sv);
    }
    
    void other_xs_sub (SV* sv) : ALIAS(other_name=1, yet_another=2) { // PPCODE
        xPUSHi(1);
        xPUSHi(2);
    }
        
is replaced with code

    char*
    my_xs_sub (SV* sv)
    CODE:
        if (badsv(sv)) XSRETURN_UNDEF;
        RETVAL = process(sv);
    OUTPUT:
        RETVAL
    
    void
    other_xs_sub (SV* sv)
    ALIAS:
        other_name=1
        yet_another=2
    PPCODE:
        xPUSHi(1);
        xPUSHi(2);
    
Note that writing

    int myfunc (int a)
    
    int myfunc (int a): ALIAS(other_name=1)

will result in default ParseXS behaviour (calling C function myfunc(a) and returning its result). That's because it has no body.

However this function has a body (empty) and therefore prevents default behaviour

    int myfunc (int a) {}
    
It is possible to have split C<BOOT> section across multiple xs/xsi source. The
special macros-like keywords are available in .xs/.xsi files: C<__MODULE__> and C<__PACKAGE__>,
they will be replaced with corresponding string literals of the most recently parsed XS header.
Here is an example:

	# module.xs
	MODULE = My::Module                PACKAGE = My::Module

	INCLUDE: my-package1.xsi

	INCLUDE: my-package2.xsi

	# my-package1.xsi
	MODULE = My::Module                PACKAGE = My::Module::Package1

	BOOT {
		hello(__PACKAGE__);
	}

	# my-package2.xsi
	MODULE = My::Module                PACKAGE = My::Module::Package2

	BOOT {
		world(__PACKAGE__);
	}

Will be merged into:

	BOOT {
		hello("My::Module::Package1");
		world("My::Module::Package2");
	}

    
=head1 ENVIRONMENT VARIABLES

=over

=item CC

=item COMPILER

Allows to redefine the compiler in C<CC> setting.

=back

=head1 AUTHOR

Pronin Oleg <syber@crazypanda.ru>, Crazy Panda LTD

=head1 LICENSE

You may distribute this code under the same terms as Perl itself.

=cut