#line 1
package Module::Install;

# For any maintainers:
# The load order for Module::Install is a bit magic.
# It goes something like this...
#
# IF ( host has Module::Install installed, creating author mode ) {
#     1. Makefile.PL calls "use inc::Module::Install"
#     2. $INC{inc/Module/Install.pm} set to installed version of inc::Module::Install
#     3. The installed version of inc::Module::Install loads
#     4. inc::Module::Install calls "require Module::Install"
#     5. The ./inc/ version of Module::Install loads
# } ELSE {
#     1. Makefile.PL calls "use inc::Module::Install"
#     2. $INC{inc/Module/Install.pm} set to ./inc/ version of Module::Install
#     3. The ./inc/ version of Module::Install loads
# }

BEGIN {
	require 5.004;
}
use strict 'vars';

use vars qw{$VERSION};
BEGIN {
	# All Module::Install core packages now require synchronised versions.
	# This will be used to ensure we don't accidentally load old or
	# different versions of modules.
	# This is not enforced yet, but will be some time in the next few
	# releases once we can make sure it won't clash with custom
	# Module::Install extensions.
	$VERSION = '0.70';
}





# Whether or not inc::Module::Install is actually loaded, the
# $INC{inc/Module/Install.pm} is what will still get set as long as
# the caller loaded module this in the documented manner.
# If not set, the caller may NOT have loaded the bundled version, and thus
# they may not have a MI version that works with the Makefile.PL. This would
# result in false errors or unexpected behaviour. And we don't want that.
my $file = join( '/', 'inc', split /::/, __PACKAGE__ ) . '.pm';
unless ( $INC{$file} ) { die <<"END_DIE" }

Please invoke ${\__PACKAGE__} with:

	use inc::${\__PACKAGE__};

not:

	use ${\__PACKAGE__};

END_DIE





# If the script that is loading Module::Install is from the future,
# then make will detect this and cause it to re-run over and over
# again. This is bad. Rather than taking action to touch it (which
# is unreliable on some platforms and requires write permissions)
# for now we should catch this and refuse to run.
if ( -f $0 and (stat($0))[9] > time ) { die <<"END_DIE" }

Your installer $0 has a modification time in the future.

This is known to create infinite loops in make.

Please correct this, then run $0 again.

END_DIE





# Build.PL was formerly supported, but no longer is due to excessive
# difficulty in implementing every single feature twice.
if ( $0 =~ /Build.PL$/i or -f 'Build.PL' ) { die <<"END_DIE" }

Module::Install no longer supports Build.PL.

It was impossible to maintain duel backends, and has been deprecated.

Please remove all Build.PL files and only use the Makefile.PL installer.

END_DIE





use Cwd        ();
use File::Find ();
use File::Path ();
use FindBin;

*inc::Module::Install::VERSION = *VERSION;
@inc::Module::Install::ISA     = __PACKAGE__;

sub autoload {
	my $self = shift;
	my $who  = $self->_caller;
	my $cwd  = Cwd::cwd();
	my $sym  = "${who}::AUTOLOAD";
	$sym->{$cwd} = sub {
		my $pwd = Cwd::cwd();
		if ( my $code = $sym->{$pwd} ) {
			# delegate back to parent dirs
			goto &$code unless $cwd eq $pwd;
		}
		$$sym =~ /([^:]+)$/ or die "Cannot autoload $who - $sym";
		unshift @_, ( $self, $1 );
		goto &{$self->can('call')} unless uc($1) eq $1;
	};
}

sub import {
	my $class = shift;
	my $self  = $class->new(@_);
	my $who   = $self->_caller;

	unless ( -f $self->{file} ) {
		require "$self->{path}/$self->{dispatch}.pm";
		File::Path::mkpath("$self->{prefix}/$self->{author}");
		$self->{admin} = "$self->{name}::$self->{dispatch}"->new( _top => $self );
		$self->{admin}->init;
		@_ = ($class, _self => $self);
		goto &{"$self->{name}::import"};
	}

	*{"${who}::AUTOLOAD"} = $self->autoload;
	$self->preload;

	# Unregister loader and worker packages so subdirs can use them again
	delete $INC{"$self->{file}"};
	delete $INC{"$self->{path}.pm"};

	return 1;
}

sub preload {
	my ($self) = @_;

	unless ( $self->{extensions} ) {
		$self->load_extensions(
			"$self->{prefix}/$self->{path}", $self
		);
	}

	my @exts = @{$self->{extensions}};
	unless ( @exts ) {
		my $admin = $self->{admin};
		@exts = $admin->load_all_extensions;
	}

	my %seen;
	foreach my $obj ( @exts ) {
		while (my ($method, $glob) = each %{ref($obj) . '::'}) {
			next unless $obj->can($method);
			next if $method =~ /^_/;
			next if $method eq uc($method);
			$seen{$method}++;
		}
	}

	my $who = $self->_caller;
	foreach my $name ( sort keys %seen ) {
		*{"${who}::$name"} = sub {
			${"${who}::AUTOLOAD"} = "${who}::$name";
			goto &{"${who}::AUTOLOAD"};
		};
	}
}

sub new {
	my ($class, %args) = @_;

	# ignore the prefix on extension modules built from top level.
	my $base_path = Cwd::abs_path($FindBin::Bin);
	unless ( Cwd::abs_path(Cwd::cwd()) eq $base_path ) {
		delete $args{prefix};
	}

	return $args{_self} if $args{_self};

	$args{dispatch} ||= 'Admin';
	$args{prefix}   ||= 'inc';
	$args{author}   ||= ($^O eq 'VMS' ? '_author' : '.author');
	$args{bundle}   ||= 'inc/BUNDLES';
	$args{base}     ||= $base_path;
	$class =~ s/^\Q$args{prefix}\E:://;
	$args{name}     ||= $class;
	$args{version}  ||= $class->VERSION;
	unless ( $args{path} ) {
		$args{path}  = $args{name};
		$args{path}  =~ s!::!/!g;
	}
	$args{file}     ||= "$args{base}/$args{prefix}/$args{path}.pm";

	bless( \%args, $class );
}

sub call {
	my ($self, $method) = @_;
	my $obj = $self->load($method) or return;
        splice(@_, 0, 2, $obj);
	goto &{$obj->can($method)};
}

sub load {
	my ($self, $method) = @_;

	$self->load_extensions(
		"$self->{prefix}/$self->{path}", $self
	) unless $self->{extensions};

	foreach my $obj (@{$self->{extensions}}) {
		return $obj if $obj->can($method);
	}

	my $admin = $self->{admin} or die <<"END_DIE";
The '$method' method does not exist in the '$self->{prefix}' path!
Please remove the '$self->{prefix}' directory and run $0 again to load it.
END_DIE

	my $obj = $admin->load($method, 1);
	push @{$self->{extensions}}, $obj;

	$obj;
}

sub load_extensions {
	my ($self, $path, $top) = @_;

	unless ( grep { lc $_ eq lc $self->{prefix} } @INC ) {
		unshift @INC, $self->{prefix};
	}

	foreach my $rv ( $self->find_extensions($path) ) {
		my ($file, $pkg) = @{$rv};
		next if $self->{pathnames}{$pkg};

		local $@;
		my $new = eval { require $file; $pkg->can('new') };
		unless ( $new ) {
			warn $@ if $@;
			next;
		}
		$self->{pathnames}{$pkg} = delete $INC{$file};
		push @{$self->{extensions}}, &{$new}($pkg, _top => $top );
	}

	$self->{extensions} ||= [];
}

sub find_extensions {
	my ($self, $path) = @_;

	my @found;
	File::Find::find( sub {
		my $file = $File::Find::name;
		return unless $file =~ m!^\Q$path\E/(.+)\.pm\Z!is;
		my $subpath = $1;
		return if lc($subpath) eq lc($self->{dispatch});

		$file = "$self->{path}/$subpath.pm";
		my $pkg = "$self->{name}::$subpath";
		$pkg =~ s!/!::!g;

		# If we have a mixed-case package name, assume case has been preserved
		# correctly.  Otherwise, root through the file to locate the case-preserved
		# version of the package name.
		if ( $subpath eq lc($subpath) || $subpath eq uc($subpath) ) {
			open PKGFILE, "<$subpath.pm" or die "find_extensions: Can't open $subpath.pm: $!";
			my $in_pod = 0;
			while ( <PKGFILE> ) {
				$in_pod = 1 if /^=\w/;
				$in_pod = 0 if /^=cut/;
				next if ($in_pod || /^=cut/);  # skip pod text
				next if /^\s*#/;               # and comments
				if ( m/^\s*package\s+($pkg)\s*;/i ) {
					$pkg = $1;
					last;
				}
			}
			close PKGFILE;
		}

		push @found, [ $file, $pkg ];
	}, $path ) if -d $path;

	@found;
}

sub _caller {
	my $depth = 0;
	my $call  = caller($depth);
	while ( $call eq __PACKAGE__ ) {
		$depth++;
		$call = caller($depth);
	}
	return $call;
}

1;

# Copyright 2008 Adam Kennedy.
