make perlbrew installl able to accept an URL to skaji/relocatable-p…

…erl tarball.

It should be able to accept URLs found on this page:

    https://github.com/skaji/relocatable-perl/releases

For example:

    perlbrew install https://github.com/skaji/relocatable-perl/releases/download/5.40.0.0/perl-linux-amd64.tar.gz

Or, with `--as` parameter:

    perlbrew install https://github.com/skaji/relocatable-perl/releases/download/5.40.0.0/perl-linux-amd64.tar.gz --as perl-5.40

Currently this only download + extract the tarball, then move its
content to the installation dir, without checking whether os/arch
actually matches current environment.

lib/App/perlbrew.pm

@@ -21,10 +21,10 @@ BEGIN {
 use Getopt::Long ();
 use CPAN::Perl::Releases ();
 use JSON::PP qw( decode_json );
-use File::Copy qw( copy );
+use File::Copy qw( copy move );
 use Capture::Tiny ();
 
-use App::Perlbrew::Util qw( files_are_the_same uniq find_similar_tokens );
+use App::Perlbrew::Util qw( files_are_the_same uniq find_similar_tokens looks_like_url_of_skaji_relocatable_perl );
 use App::Perlbrew::Path ();
 use App::Perlbrew::Path::Root ();
 use App::Perlbrew::HTTP qw( http_download http_get );
@@ -1227,6 +1227,10 @@ sub run_command_install {
         exit(-1);
     }
 
+    if ( my $detail = looks_like_url_of_skaji_relocatable_perl($dist) ) {
+        return $self->do_install_skaji_relocatable_perl($detail);
+    }
+
     $self->{dist_name} = $dist;    # for help msg generation, set to non
                                    # normalized name
 
@@ -1630,6 +1634,64 @@ INSTALL
     return;
 }
 
+sub do_install_skaji_relocatable_perl {
+    my ($self, $detail) = @_;
+
+    my $installation_name = $self->{as} || ("skaji-relocatable-perl-" . $detail->{version});
+    my $installation_path = $self->root->perls->child($installation_name);
+
+    die "ERROR: Installation target \"${installation_name}\" already exists\n"
+        if $installation_path->exists;
+
+    my $path = $self->root->dists
+        ->child("skaji-relocatable-perl")
+        ->child($detail->{version})
+        ->mkpath()
+        ->child($detail->{original_filename});
+
+    if (-f $path) {
+        print "Re-using the downloaded $path\n";
+    } else {
+        my $url = $detail->{url};
+        print "Downloading $url as $path\n";
+        my $error = http_download( $detail->{url}, $path );
+        if ($error) {
+            die "Failed to download from $url\nError: $error";
+        }
+    }
+
+    my $extracted_path = $self->do_extract_skaji_relocatable_perl_tarball($detail, $path);
+
+    move $extracted_path, $installation_path;
+
+    print "$installation_name is installed at $installation_path.\n";
+
+    print "$installation_name is successfully installed.\n";
+}
+
+sub do_extract_skaji_relocatable_perl_tarball {
+    my ($self, $detail, $tarball_path) = @_;
+
+    my $workdir = $self->builddir
+        ->child("skaji-relocatable-perl")
+        ->child($detail->{version});
+
+    $workdir->rmpath()
+        if $workdir->exists();
+
+    $workdir->mkpath();
+
+    my $tarx = "tar xzf";
+    my $extract_command = "cd $workdir; $tarx $tarball_path";
+
+    system($extract_command) == 0
+        or die "Failed to extract $tarball_path";
+
+    my ($extracted_path) = $workdir->children;
+
+    return $extracted_path;
+}
+
 sub do_install_program_from_url {
     my ( $self, $url, $program_name, $body_filter ) = @_;