Changelogging

[gitmo/Mouse.git] / lib / Mouse / Util.pm

diff --git a/lib/Mouse/Util.pm b/lib/Mouse/Util.pm
index 25de2ab..bcb865e 100644 (file)
--- a/lib/Mouse/Util.pm
+++ b/lib/Mouse/Util.pm
@@ -6,9 +6,12 @@ use Carp qw(confess);
 use B ();
 
 our @EXPORT_OK = qw(
+    load_class
+    is_class_loaded
     get_linear_isa
     apply_all_roles
     get_code_info
+    not_supported
 );
 our %EXPORT_TAGS = (
     all  => \@EXPORT_OK,
@@ -52,8 +55,9 @@ BEGIN {
         }
     }
 
-    no strict 'refs';
-    *{ __PACKAGE__ . '::get_linear_isa'} = $impl;
+
+    no warnings 'once';
+    *get_linear_isa = $impl;
 }
 
 { # taken from Sub::Identify
@@ -100,12 +104,11 @@ BEGIN {
 }
 
 # taken from Class/MOP.pm
-sub _is_valid_class_name {
+sub is_valid_class_name {
     my $class = shift;
 
     return 0 if ref($class);
     return 0 unless defined($class);
-    return 0 unless length($class);
 
     return 1 if $class =~ /^\w+(?:::\w+)*$/;
 
@@ -120,11 +123,6 @@ sub load_first_existing_class {
     my $found;
     my %exceptions;
     for my $class (@classes) {
-        unless ( _is_valid_class_name($class) ) {
-            my $display = defined($class) ? $class : 'undef';
-            confess "Invalid class name ($display)";
-        }
-
         my $e = _try_load_one_class($class);
 
         if ($e) {
@@ -150,7 +148,12 @@ sub load_first_existing_class {
 sub _try_load_one_class {
     my $class = shift;
 
-    return if Mouse::is_class_loaded($class);
+    unless ( is_valid_class_name($class) ) {
+        my $display = defined($class) ? $class : 'undef';
+        confess "Invalid class name ($display)";
+    }
+
+    return if is_class_loaded($class);
 
     my $file = $class . '.pm';
     $file =~ s{::}{/}g;
@@ -162,6 +165,50 @@ sub _try_load_one_class {
     };
 }
 
+
+sub load_class {
+    my $class = shift;
+    my $e = _try_load_one_class($class);
+    confess "Could not load class ($class) because : $e" if $e;
+
+    return 1;
+}
+
+my %is_class_loaded_cache;
+sub is_class_loaded {
+    my $class = shift;
+
+    return 0 if ref($class) || !defined($class) || !length($class);
+
+    return 1 if $is_class_loaded_cache{$class};
+
+    # walk the symbol table tree to avoid autovififying
+    # \*{${main::}{"Foo::"}} == \*main::Foo::
+
+    my $pack = \%::;
+    foreach my $part (split('::', $class)) {
+        my $entry = \$pack->{$part . '::'};
+        return 0 if ref($entry) ne 'GLOB';
+        $pack = *{$entry}{HASH} or return 0;
+    }
+
+    # check for $VERSION or @ISA
+    return ++$is_class_loaded_cache{$class} if exists $pack->{VERSION}
+             && defined *{$pack->{VERSION}}{SCALAR} && defined ${ $pack->{VERSION} };
+    return ++$is_class_loaded_cache{$class} if exists $pack->{ISA}
+             && defined *{$pack->{ISA}}{ARRAY} && @{ $pack->{ISA} } != 0;
+
+    # check for any method
+    foreach my $name( keys %{$pack} ) {
+        my $entry = \$pack->{$name};
+        return ++$is_class_loaded_cache{$class} if ref($entry) ne 'GLOB' || defined *{$entry}{CODE};
+    }
+
+    # fail
+    return 0;
+}
+
+
 sub apply_all_roles {
     my $meta = Mouse::Meta::Class->initialize(shift);
 
@@ -175,18 +222,12 @@ sub apply_all_roles {
         } else {
             push @roles, [ $_[$i] => {} ];
         }
+        my $role_name = $roles[-1][0];
+        load_class($role_name);
+        ( $role_name->can('meta') && $role_name->meta->isa('Mouse::Meta::Role') )
+            || $meta->throw_error("You can only consume roles, $role_name(".$role_name->meta.") is not a Mouse role");
     }
 
-    foreach my $role_spec (@roles) {
-        Mouse::load_class( $role_spec->[0] );
-    }
-
-    ( $_->[0]->can('meta') && $_->[0]->meta->isa('Mouse::Meta::Role') )
-        || confess("You can only consume roles, "
-        . $_->[0]
-        . " is not a Moose role")
-        foreach @roles;
-
     if ( scalar @roles == 1 ) {
         my ( $role, $params ) = @{ $roles[0] };
         $role->meta->apply( $meta, ( defined $params ? %$params : () ) );
@@ -197,6 +238,15 @@ sub apply_all_roles {
     return;
 }
 
+sub not_supported{
+    my($feature) = @_;
+
+    $feature ||= ( caller(1) )[3]; # subroutine name
+
+    local $Carp::CarpLevel = $Carp::CarpLevel + 2;
+    Carp::croak("Mouse does not currently support $feature");
+}
+
 1;
 
 __END__