Alien-Build

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lib/Alien/Base.pm  view on Meta::CPAN

package Alien::Base;

use strict;
use warnings;
use 5.008004;
use Carp;
use Path::Tiny ();
use Scalar::Util qw/blessed/;
use Capture::Tiny 0.17 qw/capture_stdout/;
use Text::ParseWords qw/shellwords/;
use Alien::Util;

# ABSTRACT: Base classes for Alien:: modules
our $VERSION = '2.84'; # VERSION


sub import {
  my $class = shift;

  return if $class eq __PACKAGE__;

  return if $class->runtime_prop;

  return if $class->install_type('system');

  require DynaLoader;

  # Sanity check in order to ensure that dist_dir can be found.
  # This will throw an exception otherwise.
  $class->dist_dir;

  # get a reference to %Alien::MyLibrary::AlienLoaded
  # which contains names of already loaded libraries
  # this logic may be replaced by investigating the DynaLoader arrays
  my $loaded = do {
    no strict 'refs';
    no warnings 'once';
    \%{ $class . "::AlienLoaded" };
  };

  my @libs = $class->split_flags( $class->libs );

  my @L = grep { s/^-L// } map { "$_" } @libs;  ## no critic (ControlStructures::ProhibitMutatingListFunctions)
  my @l = grep { /^-l/ } @libs;

  unshift @DynaLoader::dl_library_path, @L;

  my @libpaths;
  foreach my $l (@l) {
    next if $loaded->{$l};

    my $path = DynaLoader::dl_findfile( $l );
    unless ($path) {
      carp "Could not resolve $l";
      next;
    }

    push @libpaths, $path;
    $loaded->{$l} = $path;
  }

  push @DynaLoader::dl_resolve_using, @libpaths;

  my @librefs = map { DynaLoader::dl_load_file( $_, 0x01 ) } grep !/\.(a|lib)$/, @libpaths;
  push @DynaLoader::dl_librefs, @librefs;

}


sub _dist_dir ($)
{
  my($dist_name) = @_;

  my @pm = split /-/, $dist_name;
  $pm[-1] .= ".pm";

  foreach my $inc (@INC)
  {
    my $pm = Path::Tiny->new($inc, @pm);
    if(-f $pm)
    {
      my $share = Path::Tiny->new($inc, qw( auto share dist ), $dist_name );
      if(-d $share)
      {
        return $share->absolute->stringify;
      }
      last;
    }
  }
  Carp::croak("unable to find dist share directory for $dist_name");
}

sub dist_dir {
  my $class = shift;

  my $dist = blessed $class || $class;
  $dist =~ s/::/-/g;

  my $dist_dir =
    $class->config('finished_installing')
      ? _dist_dir $dist
      : $class->config('working_directory');

  croak "Failed to find share dir for dist '$dist'"
    unless defined $dist_dir && -d $dist_dir;

  return $dist_dir;
}


sub new { return bless {}, $_[0] }

sub _flags
{
  my($class, $key) = @_;

  my $config = $class->runtime_prop;
  my $flags = $config->{$key};

  my $prefix = $config->{prefix};
  $prefix =~ s{\\}{/}g if $^O =~ /^(MSWin32|msys)$/;
  my $distdir = $config->{distdir};
  $distdir =~ s{\\}{/}g if $^O =~ /^(MSWin32|msys)$/;

  if(defined $flags && $prefix ne $distdir)
  {
    $flags = join ' ', map {
      my $flag = $_;
      $flag =~ s/^(-I|-L|-LIBPATH:)?\Q$prefix\E/$1$distdir/;
      $flag =~ s/(\s)/\\$1/g;
      $flag;
    } $class->split_flags($flags);
  }

  $flags;
}


sub cflags {
  my $class = shift;
  return $class->runtime_prop ? $class->_flags('cflags') : $class->_pkgconfig_keyword('Cflags');
}


sub cflags_static {
  my $class = shift;
  return $class->runtime_prop ? $class->_flags('cflags_static') : $class->_pkgconfig_keyword('Cflags', 'static');
}


sub libs {
  my $class = shift;
  return $class->runtime_prop ? $class->_flags('libs') : $class->_pkgconfig_keyword('Libs');
}


sub libs_static {
  my $class = shift;
  return $class->runtime_prop ? $class->_flags('libs_static') : $class->_pkgconfig_keyword('Libs', 'static');
}


sub version {
  my $self = shift;
  return $self->runtime_prop
    ? $self->runtime_prop->{version}
    : do {
      my $version = $self->config('version');
      chomp $version;
      $version;
    };
}


sub atleast_version {
  my $self = shift;
  my ($wantver) = @_;

  defined(my $version = $self->version) or
    croak "$self has no defined ->version";

  return $self->version_cmp($version, $wantver) >= 0;
}

sub exact_version {
  my $self = shift;
  my ($wantver) = @_;

  defined(my $version = $self->version) or
    croak "$self has no defined ->version";

  return $self->version_cmp($version, $wantver) == 0;
}

sub max_version {
  my $self = shift;
  my ($wantver) = @_;

  defined(my $version = $self->version) or
    croak "$self has no defined ->version";

  return $self->version_cmp($version, $wantver) <= 0;
}


sub version_cmp {
  shift;
  goto &Alien::Util::version_cmp;
}


sub install_type {
  my $self = shift;
  my $type = $self->config('install_type');
  return @_ ? $type eq $_[0] : $type;
}



sub is_system_install
{
  my($self) = @_;
  $self->install_type('system');
}


sub is_share_install
{
  my($self) = @_;
  $self->install_type('share');
}


sub _pkgconfig_keyword {
  my $self = shift;
  my $keyword = shift;
  my $static = shift;

  # use pkg-config if installed system-wide
  if ($self->install_type('system')) {
    my $name = $self->config('name');
    require Alien::Base::PkgConfig;
    my $command = Alien::Base::PkgConfig->pkg_config_command . " @{[ $static ? '--static' : '' ]} --\L$keyword\E $name";

    $! = 0;
    chomp ( my $pcdata = capture_stdout { system( $command ) } );

    # if pkg-config fails for whatever reason, then we try to
    # fallback on alien_provides_*
    $pcdata = '' if $! || $?;

    $pcdata =~ s/\s*$//;

    if($self->config('system_provides')) {
      if(my $system_provides = $self->config('system_provides')->{$keyword}) {
        $pcdata = length $pcdata ? "$pcdata $system_provides" : $system_provides;
      }
    }

    return $pcdata;
  }

  # use parsed info from build .pc file
  my $dist_dir = $self->dist_dir;
  my @pc = $self->_pkgconfig(@_);
  my @strings =
    grep defined,
    map { $_->keyword($keyword,
      #{ pcfiledir => $dist_dir }
    ) }
    @pc;

  if(defined $self->config('original_prefix') && $self->config('original_prefix') ne $self->dist_dir)
  {
    my $dist_dir = $self->dist_dir;
    $dist_dir =~ s{\\}{/}g if $^O eq 'MSWin32';
    my $old = quotemeta $self->config('original_prefix');
    @strings = map {
      my $flag = $_;
      $flag =~ s{^(-I|-L|-LIBPATH:)?($old)}{$1.$dist_dir}e;
      $flag =~ s/(\s)/\\$1/g;
      $flag;
    } map { $self->split_flags($_) } @strings;
  }

  return join( ' ', @strings );
}

sub _pkgconfig {
  my $self = shift;
  my %all = %{ $self->config('pkgconfig') };

  # merge in found pc files
  require File::Find;
  my $wanted = sub {
    return if ( -d or not /\.pc$/ );
    require Alien::Base::PkgConfig;
    my $pkg = Alien::Base::PkgConfig->new($_);
    $all{$pkg->{package}} = $pkg;
  };
  File::Find::find( $wanted, $self->dist_dir );

  croak "No Alien::Base::PkgConfig objects are stored!"
    unless keys %all;

  # Run through all pkgconfig objects and ensure that their modules are loaded:
  for my $pkg_obj (values %all) {
    my $perl_module_name = blessed $pkg_obj;
    my $pm = "$perl_module_name.pm";
    $pm =~ s/::/\//g;
    eval { require $pm };
  }

  return @all{@_} if @_;

  my $manual = delete $all{_manual};

  if (keys %all) {
    return values %all;
  } else {
    return $manual;
  }
}


# helper method to call Alien::MyLib::ConfigData->config(@_)
sub config {
  my $class = shift;
  $class = blessed $class || $class;

  if(my $ab_config = $class->runtime_prop)
  {
    my $key = shift;
    return $ab_config->{legacy}->{$key};
  }

  my $config = $class . '::ConfigData';
  my $pm = "$class/ConfigData.pm";
  $pm =~ s{::}{/}g;
  eval { require $pm };

  if($@)
  {
    warn "Cannot find either a share directory or a ConfigData module for $class.\n";
    my $pm = "$class.pm";
    $pm =~ s{::}{/}g;
    warn "($class loaded from $INC{$pm})\n" if $INC{$pm};
    warn "Please see https://metacpan.org/pod/distribution/Alien-Build/lib/Alien/Build/Manual/FAQ.pod#Cannot-find-either-a-share-directory-or-a-ConfigData-module\n";
    die $@;
  }

  return $config->config(@_);
}

# helper method to split flags based on the OS
sub split_flags {
  my ($class, $line) = @_;
  if( $^O eq 'MSWin32' ) {
    $class->split_flags_windows($line);
  } else {
    # $os eq 'Unix'
    $class->split_flags_unix($line);
  }
}

sub split_flags_unix {
  my ($class, $line) = @_;
  shellwords($line);
}

sub split_flags_windows {
  # NOTE a better approach would be to write a function that understands cmd.exe metacharacters.
  my ($class, $line) = @_;

  # Double the backslashes so that when they are unescaped by shellwords(),
  # they become a single backslash. This should be fine on Windows since
  # backslashes are not used to escape metacharacters in cmd.exe.
  $line =~ s,\\,\\\\,g;
  shellwords($line);
}


sub dynamic_libs {
  my ($class) = @_;

  require FFI::CheckLib;

  my @find_lib_flags;

  if($class->install_type('system')) {

    if(my $prop = $class->runtime_prop)
    {
      if($prop->{ffi_checklib}->{system})
      {
        push @find_lib_flags, @{ $prop->{ffi_checklib}->{system} };
      }
      return FFI::CheckLib::find_lib( lib => $prop->{ffi_name}, @find_lib_flags )
        if defined $prop->{ffi_name};
    }

    my $name = $class->config('ffi_name');
    unless(defined $name)
    {
      $name = $class->config('name');
      $name = '' unless defined $name;
      # strip leading lib from things like libarchive or libffi
      $name =~ s/^lib//;
      # strip trailing version numbers
      $name =~ s/-[0-9\.]+$//;
    }

    my @libpath;
    if(defined $class->libs)
    {
      foreach my $flag ($class->split_flags($class->libs))
      {
        if($flag =~ /^-L(.*)$/)
        {
          push @libpath, $1;
        }
      }
    }

    return FFI::CheckLib::find_lib(lib => $name, libpath => \@libpath, @find_lib_flags );

  } else {

    my $dir = $class->dist_dir;
    my $dynamic = Path::Tiny->new($class->dist_dir, 'dynamic');

    if(my $prop = $class->runtime_prop)
    {
      if($prop->{ffi_checklib}->{share})
      {
        push @find_lib_flags, @{ $prop->{ffi_checklib}->{share_flags} };
      }
    }

    if(-d $dynamic)
    {
      return FFI::CheckLib::find_lib(
        lib        => '*',
        libpath    => "$dynamic",
        systempath => [],
      );
    }

    return FFI::CheckLib::find_lib(
      lib        => '*',
      libpath    => $dir,
      systempath => [],
      recursive  => 1,
    );
  }
}


sub bin_dir {
  my ($class) = @_;
  if($class->install_type('system'))
  {
    my $prop = $class->runtime_prop;
    return () unless defined $prop;
    return () unless defined $prop->{system_bin_dir};
    return ref $prop->{system_bin_dir} ? @{ $prop->{system_bin_dir} } : ($prop->{system_bin_dir});
  }
  else
  {
    my $dir = Path::Tiny->new($class->dist_dir, 'bin');
    return -d $dir ? ("$dir") : ();
  }
}



sub dynamic_dir {
  my ($class) = @_;
  if($class->install_type('system'))
  {
    return ();
  }
  else
  {
    my $dir = Path::Tiny->new($class->dist_dir, 'dynamic');
    return -d $dir ? ("$dir") : ();
  }
}


sub alien_helper {
  {};
}


sub inline_auto_include {
  my ($class) = @_;
  $class->runtime_prop->{inline_auto_include} || $class->config('inline_auto_include') || []
}

sub Inline {
  my ($class, $language) = @_;
  return unless defined $language;
  return if $language !~ /^(C|CPP)$/;
  my $config = {
    # INC should arguably be for -I flags only, but
    # this improves compat with ExtUtils::Depends.
    # see gh#107, gh#108
    INC          => $class->cflags,
    LIBS         => $class->libs,
  };

  if (@{ $class->inline_auto_include } > 0) {
    $config->{AUTO_INCLUDE} = join "\n", map { "#include \"$_\"" } @{ $class->inline_auto_include };
  }

  $config;
}


{
  my %alien_build_config_cache;

  sub runtime_prop
  {
    my($class) = @_;

    if(ref($class))
    {
      # called as an instance method.
      my $self = $class;
      $class = ref $self;
      return $self->{_alt}->{runtime_prop} if defined $self->{_alt};
    }

    return $alien_build_config_cache{$class} if
      exists $alien_build_config_cache{$class};

    $alien_build_config_cache{$class} ||= do {
      my $dist = ref $class ? ref $class : $class;
      $dist =~ s/::/-/g;
      my $dist_dir = eval { _dist_dir $dist };
      return if $@;
      my $alien_json = Path::Tiny->new($dist_dir, '_alien', 'alien.json');
      return unless -r $alien_json;
      my $json = $alien_json->slurp;
      require JSON::PP;
      my $config = JSON::PP::decode_json($json);
      $config->{distdir} = $dist_dir;
      $config;
    };
  }
}


sub alt
{
  my($old, $name) = @_;
  my $new = ref $old ? (ref $old)->new : $old->new;

  my $orig;

  if(ref($old) && defined $old->{_alt})
  { $orig = $old->{_alt}->{orig} }
  else
  { $orig = $old->runtime_prop }

  require Storable;
  my $runtime_prop = Storable::dclone($orig);

lib/Alien/Base.pm  view on Meta::CPAN

=item L<Alien::Build::Manual::AlienUser>

For users of an C<Alien::libfoo> that is implemented using L<Alien::Base>.
(The developer of C<Alien::libfoo> I<should> provide the documentation
necessary, but if not, this is the place to start).

=item L<Alien::Build::Manual::AlienAuthor>

If you are writing your own L<Alien> based on L<Alien::Build> and L<Alien::Base>.

=item L<Alien::Build::Manual::FAQ>

If you have a common question that has already been answered, like
"How do I use L<alienfile> with some build system".

=item L<Alien::Build::Manual::PluginAuthor>

This is for the brave souls who want to write plugins that will work with
L<Alien::Build> + L<alienfile>.

=back

Before using an L<Alien::Base> based L<Alien> directly, please consider the following advice:

If you are wanting to use an L<Alien::Base> based L<Alien> with an XS module using L<ExtUtils::MakeMaker> or L<Module::Build>, it is highly
recommended that you use L<Alien::Base::Wrapper>, rather than using the L<Alien> directly, because it handles a number of sharp edges and avoids
pitfalls common when trying to use an L<Alien> directly with L<ExtUtils::MakeMaker>.

In the same vein, if you are wanting to use an L<Alien::Base> based L<Alien> with an XS module using L<Dist::Zilla> it is highly recommended
that you use L<Dist::Zilla::Plugin::AlienBase::Wrapper> for the same reasons.

As of version 0.28, L<FFI::CheckLib> has a good interface for working with L<Alien::Base> based L<Alien>s in fallback mode, which is
recommended.

You should typically only be using an L<Alien::Base> based L<Alien> directly, if you need to integrate it with some other system, or if it
is a tool based L<Alien> that you don't need to link.

The above synopsis and linked manual documents will lead you down the right path, but it is worth knowing before you read further in this
document.

=head1 METHODS

In the example snippets here, C<Alien::MyLibrary> represents any
subclass of L<Alien::Base>.

=head2 dist_dir

 my $dir = Alien::MyLibrary->dist_dir;

Returns the directory that contains the install root for
the packaged software, if it was built from install (i.e., if
C<install_type> is C<share>).

=head2 new

 my $alien = Alien::MyLibrary->new;

Creates an instance of an L<Alien::Base> object.  This is typically
unnecessary.

=head2 cflags

 my $cflags = Alien::MyLibrary->cflags;
 
 use Text::ParseWords qw( shellwords );
 my @cflags = shellwords( Alien::MyLibrary->cflags );

Returns the C compiler flags necessary to compile an XS
module using the alien software.  If you need this in list
form (for example if you are calling system with a list
argument) you can pass this value into C<shellwords> from
the Perl core L<Text::ParseWords> module.

=head2 cflags_static

 my $cflags = Alien::MyLibrary->cflags_static;

Same as C<cflags> above, but gets the static compiler flags,
if they are different.

=head2 libs

 my $libs = Alien::MyLibrary->libs;
 
 use Text::ParseWords qw( shellwords );
 my @cflags = shellwords( Alien::MyLibrary->libs );

Returns the library linker flags necessary to link an XS
module against the alien software.  If you need this in list
form (for example if you are calling system with a list
argument) you can pass this value into C<shellwords> from
the Perl core L<Text::ParseWords> module.

=head2 libs_static

 my $libs = Alien::MyLibrary->libs_static;

Same as C<libs> above, but gets the static linker flags,
if they are different.

=head2 version

 my $version = Alien::MyLibrary->version;

Returns the version of the alienized library or tool that was
determined at install time.

=head2 atleast_version

=head2 exact_version

=head2 max_version

 my $ok = Alien::MyLibrary->atleast_version($wanted_version);
 my $ok = Alien::MyLibrary->exact_version($wanted_version);
 my $ok = Alien::MyLibrary->max_version($wanted_version);

Returns true if the version of the alienized library or tool is at least,
exactly, or at most the version specified, respectively.

=head2 version_cmp

  $cmp = Alien::MyLibrary->version_cmp($x, $y)

Comparison method used by L</atleast_version>, L</exact_version> and
L</max_version>. May be useful to implement custom comparisons, or for
subclasses to overload to get different version comparison semantics than the
default rules, for packages that have some other rules than the F<pkg-config>
behaviour.

Should return a number less than, equal to, or greater than zero; similar in
behaviour to the C<< <=> >> and C<cmp> operators.

=head2 install_type

 my $install_type = Alien::MyLibrary->install_type;
 my $bool = Alien::MyLibrary->install_type($install_type);

Returns the install type that was used when C<Alien::MyLibrary> was
installed.  

If a type is provided (the second form in the synopsis)
returns true if the actual install type matches.  
For this use case it is recommended to use C<is_system_install> 
or C<is_share_install> instead as these are less prone to 
typographical errors.

Types include:

=over 4

=item system

The library was provided by the operating system

=item share

The library was not available when C<Alien::MyLibrary> was installed, so

lib/Alien/Base.pm  view on Meta::CPAN

     'sh configure --prefix=%{alien.install.prefix}',
     '%{gmake}',
     '%{gmake} install',
   ];
 };
 
 ...

=head2 inline_auto_include

 my(@headers) = Alien::MyLibrary->inline_auto_include;

List of header files to automatically include in inline C and C++
code when using L<Inline::C> or L<Inline::CPP>.  This is provided
as a public interface primarily so that it can be overridden at run
time.  This can also be specified in your C<Build.PL> with
L<Alien::Base::ModuleBuild> using the C<alien_inline_auto_include>
property.

=head2 runtime_prop

 my $hashref = Alien::MyLibrary->runtime_prop;

Returns a hash reference of the runtime properties computed by L<Alien::Build> during its
install process.  If the L<Alien::Base> based L<Alien> was not built using L<Alien::Build>,
then this will return undef.

=head2 alt

 my $new_alien = Alien::MyLibrary->alt($alt_name);
 my $new_alien = $old_alien->alt($alt_name);

Returns an L<Alien::Base> instance with the alternate configuration.

Some packages come with multiple libraries, and multiple C<.pc> files to
use with them.  This method can be used with C<pkg-config> plugins to
access different configurations.  (It could also be used with non-pkg-config
based packages too, though there are not as of this writing any build
time plugins that take advantage of this feature).

From your L<alienfile>

 use alienfile;
 
 plugin 'PkgConfig' => (
   pkg_name => [ 'libfoo', 'libbar', ],
 );

Then in your base class works like normal:

 package Alien::MyLibrary;
 
 use parent qw( Alien::Base );
 
 1;

Then you can use it:

 use Alien::MyLibrary;
 
 my $cflags = Alien::MyLibrary->alt('foo1')->cflags;
 my $libs   = Alien::MyLibrary->alt('foo1')->libs;

=head2 alt_names

 my @alt_names = Alien::MyLibrary->alt_names

Returns the list of all available alternative configuration names.

=head2 alt_exists

 my $bool = Alien::MyLibrary->alt_exists($alt_name)

Returns true if the given alternative configuration exists.

=head1 SUPPORT AND CONTRIBUTING

First check the L<Alien::Build::Manual::FAQ> for questions that have already been answered.

IRC: #native on irc.perl.org

L<(click for instant chatroom login)|http://chat.mibbit.com/#native@irc.perl.org>

If you find a bug, please report it on the projects issue tracker on GitHub:

=over 4

=item L<https://github.com/PerlAlien/Alien-Build/issues>

=back

Development is discussed on the projects google groups.  This is also
a reasonable place to post a question if you don't want to open an issue
in GitHub.

=over 4

=item L<https://groups.google.com/forum/#!forum/perl5-alien>

=back

If you have implemented a new feature or fixed a bug, please open a pull
request.

=over 4

=item L<https://github.com/PerlAlien/Alien-Build/pulls>

=back

=head1 SEE ALSO

=over

=item *

L<Alien::Build>

=item *

L<alienfile>