package DBIx::Custom::Class::Inspector;

=pod

=head1 NAME

DBIx::Custom::Class::Inspector - Internal use (Same as Class::Inspector)

=head1 SYNOPSIS

  use Class::Inspector;

  # Is a class installed and/or loaded

  Class::Inspector->installed( 'Foo::Class' );

  Class::Inspector->loaded( 'Foo::Class' );

  # Filename related information

  Class::Inspector->filename( 'Foo::Class' );

  Class::Inspector->resolved_filename( 'Foo::Class' );

  # Get subroutine related information

  Class::Inspector->functions( 'Foo::Class' );

  Class::Inspector->function_refs( 'Foo::Class' );

  Class::Inspector->function_exists( 'Foo::Class', 'bar' );

  Class::Inspector->methods( 'Foo::Class', 'full', 'public' );

  # Find all loaded subclasses or something

  Class::Inspector->subclasses( 'Foo::Class' );

=head1 DESCRIPTION

Class::Inspector allows you to get information about a loaded class. Most or

all of this information can be found in other ways, but they aren't always

very friendly, and usually involve a relatively high level of Perl wizardry,

or strange and unusual looking code. Class::Inspector attempts to provide 

an easier, more friendly interface to this information.

=head1 METHODS

=cut

use 5.006;

# We don't want to use strict refs anywhere in this module, since we do a

# lot of things in here that aren't strict refs friendly.

use strict qw{vars subs};

use warnings;

use File::Spec ();

# Globals

use vars qw{$VERSION $RE_IDENTIFIER $RE_CLASS $UNIX};

BEGIN {

	$VERSION = '1.25';

	# If Unicode is available, enable it so that the

	# pattern matches below match unicode method names.

	# We can safely ignore any failure here.

	SCOPE: {

		local $@;

		eval "require utf8; utf8->import";

	}

	# Predefine some regexs

	$RE_IDENTIFIER = qr/\A[^\W\d]\w*\z/s;

	$RE_CLASS      = qr/\A[^\W\d]\w*(?:(?:\'|::)\w+)*\z/s;

	# Are we on something Unix-like?

	$UNIX  = !! ( $File::Spec::ISA[0] eq 'File::Spec::Unix'  );

}

#####################################################################

# Basic Methods

=pod

=head2 installed $class

The C<installed> static method tries to determine if a class is installed

on the machine, or at least available to Perl. It does this by wrapping

around C<resolved_filename>.

Returns true if installed/available, false if the class is not installed,

or C<undef> if the class name is invalid.

=cut

sub installed {

	my $class = shift;

	!! ($class->loaded_filename($_[0]) or $class->resolved_filename($_[0]));

}

=pod

=head2 loaded $class

The C<loaded> static method tries to determine if a class is loaded by

looking for symbol table entries.

This method it uses to determine this will work even if the class does not

have its own file, but is contained inside a single file with multiple

classes in it. Even in the case of some sort of run-time loading class

being used, these typically leave some trace in the symbol table, so an

L<Autoload> or L<Class::Autouse>-based class should correctly appear

loaded.

Returns true if the class is loaded, false if not, or C<undef> if the

class name is invalid.

=cut

sub loaded {

	my $class = shift;

	my $name  = $class->_class(shift) or return undef;

	$class->_loaded($name);

}

sub _loaded {

	my $class = shift;

	my $name  = shift;

	# Handle by far the two most common cases

	# This is very fast and handles 99% of cases.

	return 1 if defined ${"${name}::VERSION"};

	return 1 if defined @{"${name}::ISA"};

	# Are there any symbol table entries other than other namespaces

	foreach ( keys %{"${name}::"} ) {

		next if substr($_, -2, 2) eq '::';

		return 1 if defined &{"${name}::$_"};

	}

	# No functions, and it doesn't have a version, and isn't anything.

	# As an absolute last resort, check for an entry in %INC

	my $filename = $class->_inc_filename($name);

	return 1 if defined $INC{$filename};

	'';

}

=pod

=head2 filename $class

For a given class, returns the base filename for the class. This will NOT

be a fully resolved filename, just the part of the filename BELOW the

C<@INC> entry.

  print Class->filename( 'Foo::Bar' );

  > Foo/Bar.pm

This filename will be returned with the right seperator for the local

platform, and should work on all platforms.

Returns the filename on success or C<undef> if the class name is invalid.

=cut

sub filename {

	my $class = shift;

	my $name  = $class->_class(shift) or return undef;

	File::Spec->catfile( split /(?:\'|::)/, $name ) . '.pm';

}

=pod

=head2 resolved_filename $class, @try_first

For a given class, the C<resolved_filename> static method returns the fully

resolved filename for a class. That is, the file that the class would be

loaded from.

This is not nescesarily the file that the class WAS loaded from, as the

value returned is determined each time it runs, and the C<@INC> include

path may change.

To get the actual file for a loaded class, see the C<loaded_filename>

method.

Returns the filename for the class, or C<undef> if the class name is

invalid.

=cut

sub resolved_filename {

	my $class     = shift;

	my $filename  = $class->_inc_filename(shift) or return undef;

	my @try_first = @_;

	# Look through the @INC path to find the file

	foreach ( @try_first, @INC ) {

		my $full = "$_/$filename";

		next unless -e $full;

		return $UNIX ? $full : $class->_inc_to_local($full);

	}

	# File not found

	'';

}

=pod

=head2 loaded_filename $class

For a given loaded class, the C<loaded_filename> static method determines

(via the C<%INC> hash) the name of the file that it was originally loaded

from.

Returns a resolved file path, or false if the class did not have it's own

file.

=cut

sub loaded_filename {

	my $class    = shift;

	my $filename = $class->_inc_filename(shift);

	$UNIX ? $INC{$filename} : $class->_inc_to_local($INC{$filename});

}

#####################################################################

# Sub Related Methods

=pod

=head2 functions $class

For a loaded class, the C<functions> static method returns a list of the

names of all the functions in the classes immediate namespace.

Note that this is not the METHODS of the class, just the functions.

Returns a reference to an array of the function names on success, or C<undef>

if the class name is invalid or the class is not loaded.

=cut

sub functions {

	my $class = shift;

	my $name  = $class->_class(shift) or return undef;

	return undef unless $class->loaded( $name );

	# Get all the CODE symbol table entries

	my @functions = sort grep { /$RE_IDENTIFIER/o }

		grep { defined &{"${name}::$_"} }

		keys %{"${name}::"};

	\@functions;

}

=pod

=head2 function_refs $class

For a loaded class, the C<function_refs> static method returns references to

all the functions in the classes immediate namespace.

Note that this is not the METHODS of the class, just the functions.

Returns a reference to an array of C<CODE> refs of the functions on

success, or C<undef> if the class is not loaded.

=cut

sub function_refs {

	my $class = shift;

	my $name  = $class->_class(shift) or return undef;

	return undef unless $class->loaded( $name );

	# Get all the CODE symbol table entries, but return

	# the actual CODE refs this time.

	my @functions = map { \&{"${name}::$_"} }

		sort grep { /$RE_IDENTIFIER/o }

		grep { defined &{"${name}::$_"} }

		keys %{"${name}::"};

	\@functions;

}

=pod

=head2 function_exists $class, $function

Given a class and function name the C<function_exists> static method will

check to see if the function exists in the class.

Note that this is as a function, not as a method. To see if a method

exists for a class, use the C<can> method for any class or object.

Returns true if the function exists, false if not, or C<undef> if the

class or function name are invalid, or the class is not loaded.

=cut

sub function_exists {

	my $class    = shift;

	my $name     = $class->_class( shift ) or return undef;

	my $function = shift or return undef;

	# Only works if the class is loaded

	return undef unless $class->loaded( $name );

	# Does the GLOB exist and its CODE part exist

	defined &{"${name}::$function"};

}

=pod

=head2 methods $class, @options

For a given class name, the C<methods> static method will returns ALL

the methods available to that class. This includes all methods available

from every class up the class' C<@ISA> tree.

Returns a reference to an array of the names of all the available methods

on success, or C<undef> if the class name is invalid or the class is not

loaded.

A number of options are available to the C<methods> method that will alter

the results returned. These should be listed after the class name, in any

order.

  # Only get public methods

  my $method = Class::Inspector->methods( 'My::Class', 'public' );

=over 4

=item public

The C<public> option will return only 'public' methods, as defined by the Perl

convention of prepending an underscore to any 'private' methods. The C<public> 

option will effectively remove any methods that start with an underscore.

=item private

The C<private> options will return only 'private' methods, as defined by the

Perl convention of prepending an underscore to an private methods. The

C<private> option will effectively remove an method that do not start with an

underscore.

B<Note: The C<public> and C<private> options are mutually exclusive>

=item full

C<methods> normally returns just the method name. Supplying the C<full> option

will cause the methods to be returned as the full names. That is, instead of

returning C<[ 'method1', 'method2', 'method3' ]>, you would instead get

C<[ 'Class::method1', 'AnotherClass::method2', 'Class::method3' ]>.

=item expanded

The C<expanded> option will cause a lot more information about method to be 

returned. Instead of just the method name, you will instead get an array

reference containing the method name as a single combined name, ala C<full>,

the seperate class and method, and a CODE ref to the actual function ( if

available ). Please note that the function reference is not guarenteed to 

be available. C<Class::Inspector> is intended at some later time, work 

with modules that have some some of common run-time loader in place ( e.g

C<Autoloader> or C<Class::Autouse> for example.

The response from C<methods( 'Class', 'expanded' )> would look something like

the following.

  [

    [ 'Class::method1',   'Class',   'method1', \&Class::method1   ],

    [ 'Another::method2', 'Another', 'method2', \&Another::method2 ],

    [ 'Foo::bar',         'Foo',     'bar',     \&Foo::bar         ],

  ]

=back

=cut

sub methods {

	my $class     = shift;

	my $name      = $class->_class( shift ) or return undef;

	my @arguments = map { lc $_ } @_;

	# Process the arguments to determine the options

	my %options = ();

	foreach ( @arguments ) {

		if ( $_ eq 'public' ) {

			# Only get public methods

			return undef if $options{private};

			$options{public} = 1;

		} elsif ( $_ eq 'private' ) {

			# Only get private methods

			return undef if $options{public};

			$options{private} = 1;

		} elsif ( $_ eq 'full' ) {

			# Return the full method name

			return undef if $options{expanded};

			$options{full} = 1;

		} elsif ( $_ eq 'expanded' ) {

			# Returns class, method and function ref

			return undef if $options{full};

			$options{expanded} = 1;

		} else {

			# Unknown or unsupported options

			return undef;

		}

	}

	# Only works if the class is loaded

	return undef unless $class->loaded( $name );

	# Get the super path ( not including UNIVERSAL )

	# Rather than using Class::ISA, we'll use an inlined version

	# that implements the same basic algorithm.

	my @path  = ();

	my @queue = ( $name );

	my %seen  = ( $name => 1 );

	while ( my $cl = shift @queue ) {

		push @path, $cl;

		unshift @queue, grep { ! $seen{$_}++ }

			map { s/^::/main::/; s/\'/::/g; $_ }

			( @{"${cl}::ISA"} );

	}

	# Find and merge the function names across the entire super path.

	# Sort alphabetically and return.

	my %methods = ();

	foreach my $namespace ( @path ) {

		my @functions = grep { ! $methods{$_} }

			grep { /$RE_IDENTIFIER/o }

			grep { defined &{"${namespace}::$_"} } 

			keys %{"${namespace}::"};

		foreach ( @functions ) {

			$methods{$_} = $namespace;

		}

	}

	# Filter to public or private methods if needed

	my @methodlist = sort keys %methods;

	@methodlist = grep { ! /^\_/ } @methodlist if $options{public};

	@methodlist = grep {   /^\_/ } @methodlist if $options{private};

	# Return in the correct format

	@methodlist = map { "$methods{$_}::$_" } @methodlist if $options{full};

	@methodlist = map { 

		[ "$methods{$_}::$_", $methods{$_}, $_, \&{"$methods{$_}::$_"} ] 

		} @methodlist if $options{expanded};

	\@methodlist;

}

#####################################################################

# Search Methods

=pod

=head2 subclasses $class

The C<subclasses> static method will search then entire namespace (and thus

B<all> currently loaded classes) to find all classes that are subclasses

of the class provided as a the parameter.

The actual test will be done by calling C<isa> on the class as a static

method. (i.e. C<My::Class-E<gt>isa($class)>.

Returns a reference to a list of the loaded classes that match the class

provided, or false is none match, or C<undef> if the class name provided

is invalid.

=cut

sub subclasses {

	my $class = shift;

	my $name  = $class->_class( shift ) or return undef;

	# Prepare the search queue

	my @found = ();

	my @queue = grep { $_ ne 'main' } $class->_subnames('');

	while ( @queue ) {

		my $c = shift(@queue); # c for class

		if ( $class->_loaded($c) ) {

			# At least one person has managed to misengineer

			# a situation in which ->isa could die, even if the

			# class is real. Trap these cases and just skip

			# over that (bizarre) class. That would at limit

			# problems with finding subclasses to only the

			# modules that have broken ->isa implementation.

			local $@;

			eval {

				if ( $c->isa($name) ) {

					# Add to the found list, but don't add the class itself

					push @found, $c unless $c eq $name;

				}

			};

		}

		# Add any child namespaces to the head of the queue.

		# This keeps the queue length shorted, and allows us

		# not to have to do another sort at the end.

		unshift @queue, map { "${c}::$_" } $class->_subnames($c);

	}

	@found ? \@found : '';

}

sub _subnames {

	my ($class, $name) = @_;

	return sort

		grep {

			substr($_, -2, 2, '') eq '::'

			and

			/$RE_IDENTIFIER/o

		}

		keys %{"${name}::"};

}

#####################################################################

# Children Related Methods

# These can go undocumented for now, until I decide if its best to

# just search the children in namespace only, or if I should do it via

# the file system.

# Find all the loaded classes below us

sub children {

	my $class = shift;

	my $name  = $class->_class(shift) or return ();

	# Find all the Foo:: elements in our symbol table

	no strict 'refs';

	map { "${name}::$_" } sort grep { s/::$// } keys %{"${name}::"};

}

# As above, but recursively

sub recursive_children {

	my $class    = shift;

	my $name     = $class->_class(shift) or return ();

	my @children = ( $name );

	# Do the search using a nicer, more memory efficient 

	# variant of actual recursion.

	my $i = 0;

	no strict 'refs';

	while ( my $namespace = $children[$i++] ) {

		push @children, map { "${namespace}::$_" }

			grep { ! /^::/ } # Ignore things like ::ISA::CACHE::

			grep { s/::$// }

			keys %{"${namespace}::"};

	}

	sort @children;

}

#####################################################################

# Private Methods

# Checks and expands ( if needed ) a class name

sub _class {

	my $class = shift;

	my $name  = shift or return '';

	# Handle main shorthand

	return 'main' if $name eq '::';

	$name =~ s/\A::/main::/;

	# Check the class name is valid

	$name =~ /$RE_CLASS/o ? $name : '';

}

# Create a INC-specific filename, which always uses '/'

# regardless of platform.

sub _inc_filename {

	my $class = shift;

	my $name  = $class->_class(shift) or return undef;

	join( '/', split /(?:\'|::)/, $name ) . '.pm';

}

# Convert INC-specific file name to local file name

sub _inc_to_local {

	# Shortcut in the Unix case

	return $_[1] if $UNIX;

	# On other places, we have to deal with an unusual path that might look

	# like C:/foo/bar.pm which doesn't fit ANY normal pattern.

	# Putting it through splitpath/dir and back again seems to normalise

	# it to a reasonable amount.

	my $class              = shift;

	my $inc_name           = shift or return undef;

	my ($vol, $dir, $file) = File::Spec->splitpath( $inc_name );

	$dir = File::Spec->catdir( File::Spec->splitdir( $dir || "" ) );

	File::Spec->catpath( $vol, $dir, $file || "" );

}

1;

=pod

=head1 SUPPORT

Bugs should be reported via the CPAN bug tracker

L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Class-Inspector>

For other issues, or commercial enhancement or support, contact the author.

=head1 AUTHOR

Adam Kennedy E<lt>adamk@cpan.orgE<gt>

=head1 SEE ALSO

L<http://ali.as/>, L<Class::Handle>

=head1 COPYRIGHT

Copyright 2002 - 2011 Adam Kennedy.

This program is free software; you can redistribute

it and/or modify it under the same terms as Perl itself.

The full text of the license can be found in the

LICENSE file included with this module.

=cut