Module::Dependency::Info(3)

NAME
Module::Dependency::Info - retrieve dependency information for scripts and modules

SYNOPSIS
        use Module::Dependency::Info;
        Module::Dependency::Info::setIndex( '/var/tmp/dependence/unified.dat' );

        # load the index (actually it's loaded automatically if needed so this is optional)
        Module::Dependency::Info::retrieveIndex();
        # or
        $refToEntireDatabase = Module::Dependency::Info::retrieveIndex();

        $listref = Module::Dependency::Info::allItems();
        $listref = Module::Dependency::Info::allScripts();

        # note the syntax here - the path of perl scripts, but the package name of modules.
        $dependencyInfo = Module::Dependency::Info::getItem( 'Foo::Bar' [, $forceReload ] );
        # and
        $dependencyInfo = Module::Dependency::Info::getItem( './blahblah.pl' [, $forceReload ] );

        $filename = Module::Dependency::Info::getFilename( 'Foo::Bar' [, $forceReload ] );
        $listref = Module::Dependency::Info::getChildren( $node [, $forceReload ] );
        $listref = Module::Dependency::Info::getParents( $node [, $forceReload ] );

        $value = Module::Dependency::Info::relationship( 'Foo::Bar', 'strict' );

        Module::Dependency::Info::dropIndex();

DESCRIPTION
This module is used to access the data structures created by Module::Dependency::Indexer OR a third-party application that creates databases of the correct format. Although you can get at the database structure itself you should use the accessor methods.

METHODS

setIndex( $filename );
    This tells the module where the database is. The default is $ENV{PERL_PMD_DB} or else /var/tmp/dependence/unified.dat

retrieveIndex();
    Loads the database into memory. You only have to do this once - after that it's there in RAM ready for use. This routine is called automatically if needed anyway. Incidentally it returns a reference to the entire data structure, but don't use it directly, use this...

$listref = Module::Dependency::Info::allItems();
    Returns a reference to an array of all the items in the currently loaded datafile. The order is whatever keys() gives us. The entries in the array are things like 'foo.pl' and 'Bar::Baz'.

$listref = Module::Dependency::Info::allScripts();
    Returns a reference ot an array of all the scripts in the currently loaded datafile. The order is whatever it is in the datafile.

$record = Module::Dependency::Info::getItem( $name [, $forceReload ] );
    Returns entire record for the thing you name, or undef if no such entry can be found (remember modules are referred to like 'Foo::Bar' whereas scripts like 'foo.pl'). Implicity loads the datafile from disk, using the current setting of the data location, if it isn't loaded. Pass in a 1 as the second argument if you want to force a reload - this may be relevant in long-lived perl processes like mod_perl, but only do it when you need to, like every 10 minutes or whatever makes sense for your application.

$filename = Module::Dependency::Info::getFilename( $node [, $forceReload ] );
    Gets the full filename for the package/script named, or undef if no record could be found.

$listref = Module::Dependency::Info::getChildren( $node [, $forceReload ] );
    Gets a list of all dependencies, i.e. packages that this item depends on, for the package/script named, or undef if no record could be found.

$listref = Module::Dependency::Info::getParents( $node [, $forceReload ] );
    Gets a list of all reverse dependencies, i.e. packages that depend upon this item, for the package/script named, or undef if no record could be found.

$value = Module::Dependency::Info::relationship( $itemName, $otherItem );
    Tells you whether, according to the current database, $itemName is related to $otherItem. $itemName is a module or script in the database (i.e. it's a file that has been indexed). Return values are:

    undef if $itemName is not in the database

    'NONE' if no link can be found (may be a false negative if links between the 2 items are not in the index)

    'PARENT' if the $otherItem depends upon $itemName

    'CHILD' if $itemName depends upon $otherItem

    'CIRCULAR' if $otherItem is both 'PARENT' and 'CHILD'.

dropIndex
    drops the current database - you generally have no need to do this unless you're trying to save memory. Usually all you need to do is setIndex followed by a retrieveIndex, get* or all* function.

DATA RECORDS
The database contains a list of all scripts (.pl and .plx files) encountered. We treat these as special because they form the 'top' of the dependency tree - they 'use' things, but they are not 'use'd themselves. It's just an array of all their nodenames (the filename, excluding the path to the file, e.g. 'foo.pl').

The main bit is a hash. The keys of the hash are one of two things: a) keys to module records are the name of the package, e.g. 'Foo::Bar'; b) keys to script records are the nodename of the file, e.g. 'foo.pl'.

A data records looks like the right-hand half of these:

        # lots of Data::Dumper output snipped
        'IFL::Beasts::Evol::RendererUtils' => {
                'filename' => '/home/system/cgi-bin/lib/IFL/Beasts/Evol/RendererUtils.pm',
                'package' => 'IFL::Beasts::Evol::RendererUtils',
                'depended_upon_by' => [
                        'IFL::Beasts::Evol::TextSkin',
                        'IFL::Beasts::Evol::HTMLSkin'
                ],
                'depends_on' => [
                        'lib',
                        'Exporter',
                        'Carp',
                        'IFL::Beasts::Evol::LanguageUtils',
                        'IFL::Beasts::Evol::MathUtils',
                        'EDUtemplate'
                ]
        },
        # lots of Data::Dumper output snipped

Or like this, for a script file:

        # lots of Data::Dumper output snipped
        'csv_validator.pl' => {
                'filename' => '/home/system/cgi-bin/education/user_reg/csv_validator.pl',
                'package' => 'csv_validator.pl',
                'depends_on' => [
                        'CGI',
                        'EDUprofile',
                        'LWP::Simple',
                        'File::Find'
                ]
        },
        # lots of Data::Dumper output snipped

But of course you should use the accessor methods to get at the information.

DEBUGGING
There is a TRACE stub function, and the module uses TRACE() to log activity. Override our TRACE with your own routine, e.g. one that prints to STDERR, to see these messages.

SEE ALSO
Module::Dependency and the README files.

VERSION
$Id: Info.pm 6643 2006-07-12 20:23:31Z timbo $