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+package TAP::Parser::IteratorFactory;
+
+use strict;
+use vars qw($VERSION @ISA);
+
+use TAP::Object ();
+
+use Carp qw( confess );
+use File::Basename qw( fileparse );
+
+@ISA = qw(TAP::Object);
+
+use constant handlers => [];
+
+=head1 NAME
+
+TAP::Parser::IteratorFactory - Figures out which SourceHandler objects to use for a given Source
+
+=head1 VERSION
+
+Version 3.20
+
+=cut
+
+$VERSION = '3.20';
+
+=head1 SYNOPSIS
+
+ use TAP::Parser::IteratorFactory;
+ my $factory = TAP::Parser::IteratorFactory->new({ %config });
+ my $iterator = $factory->make_iterator( $filename );
+
+=head1 DESCRIPTION
+
+This is a factory class that takes a L<TAP::Parser::Source> and runs it through all the
+registered L<TAP::Parser::SourceHandler>s to see which one should handle the source.
+
+If you're a plugin author, you'll be interested in how to L</register_handler>s,
+how L</detect_source> works.
+
+=head1 METHODS
+
+=head2 Class Methods
+
+=head3 C<new>
+
+Creates a new factory class:
+
+ my $sf = TAP::Parser::IteratorFactory->new( $config );
+
+C<$config> is optional. If given, sets L</config> and calls L</load_handlers>.
+
+=cut
+
+sub _initialize {
+ my ( $self, $config ) = @_;
+ $self->config( $config || {} )->load_handlers;
+ return $self;
+}
+
+=head3 C<register_handler>
+
+Registers a new L<TAP::Parser::SourceHandler> with this factory.
+
+ __PACKAGE__->register_handler( $handler_class );
+
+=head3 C<handlers>
+
+List of handlers that have been registered.
+
+=cut
+
+sub register_handler {
+ my ( $class, $dclass ) = @_;
+
+ confess("$dclass must implement can_handle & make_iterator methods!")
+ unless UNIVERSAL::can( $dclass, 'can_handle' )
+ && UNIVERSAL::can( $dclass, 'make_iterator' );
+
+ my $handlers = $class->handlers;
+ push @{$handlers}, $dclass
+ unless grep { $_ eq $dclass } @{$handlers};
+
+ return $class;
+}
+
+##############################################################################
+
+=head2 Instance Methods
+
+=head3 C<config>
+
+ my $cfg = $sf->config;
+ $sf->config({ Perl => { %config } });
+
+Chaining getter/setter for the configuration of the available source handlers.
+This is a hashref keyed on handler class whose values contain config to be passed
+onto the handlers during detection & creation. Class names may be fully qualified
+or abbreviated, eg:
+
+ # these are equivalent
+ $sf->config({ 'TAP::Parser::SourceHandler::Perl' => { %config } });
+ $sf->config({ 'Perl' => { %config } });
+
+=cut
+
+sub config {
+ my $self = shift;
+ return $self->{config} unless @_;
+ unless ( 'HASH' eq ref $_[0] ) {
+ $self->_croak('Argument to &config must be a hash reference');
+ }
+ $self->{config} = shift;
+ return $self;
+}
+
+sub _last_handler {
+ my $self = shift;
+ return $self->{last_handler} unless @_;
+ $self->{last_handler} = shift;
+ return $self;
+}
+
+sub _testing {
+ my $self = shift;
+ return $self->{testing} unless @_;
+ $self->{testing} = shift;
+ return $self;
+}
+
+##############################################################################
+
+=head3 C<load_handlers>
+
+ $sf->load_handlers;
+
+Loads the handler classes defined in L</config>. For example, given a config:
+
+ $sf->config({
+ MySourceHandler => { some => 'config' },
+ });
+
+C<load_handlers> will attempt to load the C<MySourceHandler> class by looking in
+C<@INC> for it in this order:
+
+ TAP::Parser::SourceHandler::MySourceHandler
+ MySourceHandler
+
+C<croak>s on error.
+
+=cut
+
+sub load_handlers {
+ my ($self) = @_;
+ for my $handler ( keys %{ $self->config } ) {
+ my $sclass = $self->_load_handler($handler);
+
+ # TODO: store which class we loaded anywhere?
+ }
+ return $self;
+}
+
+sub _load_handler {
+ my ( $self, $handler ) = @_;
+
+ my @errors;
+ for my $dclass ( "TAP::Parser::SourceHandler::$handler", $handler ) {
+ return $dclass
+ if UNIVERSAL::can( $dclass, 'can_handle' )
+ && UNIVERSAL::can( $dclass, 'make_iterator' );
+
+ eval "use $dclass";
+ if ( my $e = $@ ) {
+ push @errors, $e;
+ next;
+ }
+
+ return $dclass
+ if UNIVERSAL::can( $dclass, 'can_handle' )
+ && UNIVERSAL::can( $dclass, 'make_iterator' );
+ push @errors,
+ "handler '$dclass' does not implement can_handle & make_iterator";
+ }
+
+ $self->_croak(
+ "Cannot load handler '$handler': " . join( "\n", @errors ) );
+}
+
+##############################################################################
+
+=head3 C<make_iterator>
+
+ my $iterator = $src_factory->make_iterator( $source );
+
+Given a L<TAP::Parser::Source>, finds the most suitable L<TAP::Parser::SourceHandler>
+to use to create a L<TAP::Parser::Iterator> (see L</detect_source>). Dies on error.
+
+=cut
+
+sub make_iterator {
+ my ( $self, $source ) = @_;
+
+ $self->_croak('no raw source defined!') unless defined $source->raw;
+
+ $source->config( $self->config )->assemble_meta;
+
+ # is the raw source already an object?
+ return $source->raw
+ if ( $source->meta->{is_object}
+ && UNIVERSAL::isa( $source->raw, 'TAP::Parser::SourceHandler' ) );
+
+ # figure out what kind of source it is
+ my $sd_class = $self->detect_source($source);
+ $self->_last_handler($sd_class);
+
+ return if $self->_testing;
+
+ # create it
+ my $iterator = $sd_class->make_iterator($source);
+
+ return $iterator;
+}
+
+=head3 C<detect_source>
+
+Given a L<TAP::Parser::Source>, detects what kind of source it is and
+returns I<one> L<TAP::Parser::SourceHandler> (the most confident one). Dies
+on error.
+
+The detection algorithm works something like this:
+
+ for (@registered_handlers) {
+ # ask them how confident they are about handling this source
+ $confidence{$handler} = $handler->can_handle( $source )
+ }
+ # choose the most confident handler
+
+Ties are handled by choosing the first handler.
+
+=cut
+
+sub detect_source {
+ my ( $self, $source ) = @_;
+
+ confess('no raw source ref defined!') unless defined $source->raw;
+
+ # find a list of handlers that can handle this source:
+ my %handlers;
+ for my $dclass ( @{ $self->handlers } ) {
+ my $confidence = $dclass->can_handle($source);
+
+ # warn "handler: $dclass: $confidence\n";
+ $handlers{$dclass} = $confidence if $confidence;
+ }
+
+ if ( !%handlers ) {
+
+ # use Data::Dump qw( pp );
+ # warn pp( $meta );
+
+ # error: can't detect source
+ my $raw_source_short = substr( ${ $source->raw }, 0, 50 );
+ confess("Cannot detect source of '$raw_source_short'!");
+ return;
+ }
+
+ # if multiple handlers can handle it, choose the most confident one
+ my @handlers = (
+ map {$_}
+ sort { $handlers{$a} cmp $handlers{$b} }
+ keys %handlers
+ );
+
+ # this is really useful for debugging handlers:
+ if ( $ENV{TAP_HARNESS_SOURCE_FACTORY_VOTES} ) {
+ warn(
+ "votes: ",
+ join( ', ', map {"$_: $handlers{$_}"} @handlers ),
+ "\n"
+ );
+ }
+
+ # return 1st
+ return pop @handlers;
+}
+
+1;
+
+__END__
+
+=head1 SUBCLASSING
+
+Please see L<TAP::Parser/SUBCLASSING> for a subclassing overview.
+
+=head2 Example
+
+If we've done things right, you'll probably want to write a new source,
+rather than sub-classing this (see L<TAP::Parser::SourceHandler> for that).
+
+But in case you find the need to...
+
+ package MyIteratorFactory;
+
+ use strict;
+ use vars '@ISA';
+
+ use TAP::Parser::IteratorFactory;
+
+ @ISA = qw( TAP::Parser::IteratorFactory );
+
+ # override source detection algorithm
+ sub detect_source {
+ my ($self, $raw_source_ref, $meta) = @_;
+ # do detective work, using $meta and whatever else...
+ }
+
+ 1;
+
+=head1 AUTHORS
+
+Steve Purkis
+
+=head1 ATTRIBUTION
+
+Originally ripped off from L<Test::Harness>.
+
+Moved out of L<TAP::Parser> & converted to a factory class to support
+extensible TAP source detective work by Steve Purkis.
+
+=head1 SEE ALSO
+
+L<TAP::Object>,
+L<TAP::Parser>,
+L<TAP::Parser::SourceHandler>,
+L<TAP::Parser::SourceHandler::File>,
+L<TAP::Parser::SourceHandler::Perl>,
+L<TAP::Parser::SourceHandler::RawTAP>,
+L<TAP::Parser::SourceHandler::Handle>,
+L<TAP::Parser::SourceHandler::Executable>
+
+=cut
+