dist.pl6

# So a CompUnit::Repository could use $dist.meta to access provides, resources, etc and let the Distribution
# itself deal with the relative paths so the CU::R can recieve the data directly and save/install it somewhere

# Distribution::Local
# git clone https://github.com/User/repo.git && cd repo && echo $this-file > dist.pl6
# perl6 dist.pl6 --path=. --dir                                        # same as above, but with a directory
# perl6 dist.pl6 --path=. --dir provides ModuleName lib/ModuleName.pm6 # ...
# perl6 test.pl6 --path=. --dir resources mylib                        # or direct access to "special paths" like resources, hooks, t, bin

# Distribution::Tar
# wget --no-check-certificate https://github.com/User/repo/archive/master.tar.gz && echo $this-file > dist.pl6
# perl6 dist.pl6 --path=master.tar.gz --tar                                        # view meta data from tar archive distribution
# perl6 dist.pl6 --path=master.tar.gz --tar provides ModuleName lib/ModuleName.pm6 # get data from tar archive for meta item
# perl6 test.pl6 --path=master.tar.gz --tar resources mylib                        # or access to "special paths" like resources, hooks, t, bin

# https://design.perl6.org/S22.html#Distribution
role DistributionS22 {
    # CU::R and installers access to meta data.
    # Distribution itself would just be `method meta meta { $.hash } }`
    method meta    { ... }

    # API access to meta items that represent a would be file
    method content { ... }

    # Not part of the spec. Really just verifies the entry exists for `.content`
    method at-key(*@keys) {
        my $wanted = @keys[*-1];
        my $resource   = +@keys == 1
            ?? $wanted
            !! @keys[0..*-2].reduce(-> $n1 is rw, $n2 {
                once $n1 = self.meta{$n1};
                $n1{$n2}
            });

        $resource ne 'resources'
            ??  $wanted eq $resource
                ?? $wanted
                !! die("Can't find requested meta file key {@keys[*-1]}")
            !! ($resource ~ $*SPEC.dir-sep ~ $wanted);
    }
}

# CompUnit::Repository::(FileSystem|Installer) could both use this
class Distribution::Local does DistributionS22 {
    has $.path;

    method new($path) { self.bless(:$path) }

    method meta { %(from-json($!path.IO.child('META6.json').slurp)) }

    method content(*@keys) {
        my $abspath = $.at-key(|@keys).IO.abspath;
        die "Can't find resource with path: {$abspath}" unless $abspath.IO.f;
        $abspath.IO.slurp
    }
}

# CompUnit::Repository::(FileSystem|Installer) could both use this
class Distribution::Tar is Distribution::Local does DistributionS22 {
    has %!meta;

    method meta {
        once {
            my $proc = run('tar', '--to-stdout', '--extract', '-zf', $.path, self!tar-path('META6.json'), :out, :bin);
            %!meta = %(from-json($proc.out.slurp-rest));
            $proc.out.close;
        }
        %!meta
    }

    method content(*@keys) {
        my $tar-path = self!tar-path($.at-key(|@keys));
        my $proc = run('tar', '--to-stdout', '--extract', '-zf', $.path, $tar-path, :out, :bin);
        my $io = $proc.out.slurp-rest;
        $proc.out.close;
        $io;
    }

    method !tar-path($path-part) {
        my $proc = run('tar', '--list', '-f', $.path, :out);
        my @extracted-paths <== grep *.defined <== $proc.out.lines;
        $proc.out.close;
        @extracted-paths[0] ~ $path-part;
    }
}

#| where --path=<dist directory containing META6json>
multi sub MAIN(*@keys, :$path! where *.IO.child('META6.json').e, Bool :$dir where *.so) {
    say "Distribution from: $path";
    my $dist-local = Distribution::Local.new($path);
    say @keys.elems ?? $dist-local.content(|@keys) !! $dist-local.meta;
}

#| where --path=<.tar.gz archive containing root/META6.json, like from github>
multi sub MAIN(*@keys, :$path! where *.ends-with('.tar.gz'), Bool :$tar where *.so) {
    say "Distribution from: $path";
    my $dist-tar = Distribution::Tar.new($path);
    say @keys.elems ?? $dist-tar.content(|@keys) !! $dist-tar.meta;
}