Faster File::Compare

[p5sagit/p5-mst-13.2.git] / lib / AutoLoader.pm

diff --git a/lib/AutoLoader.pm b/lib/AutoLoader.pm
index e24e139..be6429e 100644 (file)
--- a/lib/AutoLoader.pm
+++ b/lib/AutoLoader.pm
@@ -11,7 +11,7 @@ AutoLoader - load functions only on demand
     package FOOBAR;
     use Exporter;
     use AutoLoader;
-    @ISA = (Exporter, AutoLoader);
+    @ISA = qw(Exporter AutoLoader);
 
 =head1 DESCRIPTION
 
@@ -35,6 +35,31 @@ F</usr/local/lib/perl5/POSIX.pm>. The autoloader will look for perl
 subroutines for this package in F</usr/local/lib/perl5/auto/POSIX/*.al>.
 The C<.al> file is named using the subroutine name, sans package.
 
+=head2 Loading Stubs
+
+The B<AutoLoader> module provide a special import() method that will
+load the stubs (from F<autosplit.ix> file) of the calling module.
+These stubs are needed to make inheritance work correctly for class
+modules.
+
+Modules that inherit from B<AutoLoader> should always ensure that they
+override the AutoLoader->import() method.  If the module inherit from
+B<Exporter> like shown in the I<synopis> section this is already taken
+care of.  For class methods an empty import() would do nicely:
+
+  package MyClass;
+  use AutoLoader;        # load stubs
+  @ISA=qw(AutoLoader);
+  sub import {}          # hide AutoLoader::import
+
+You can also set up autoloading by importing the AUTOLOAD function
+instead of inheriting from B<AutoLoader>:
+
+  package MyClass;
+  use AutoLoader;        # load stubs
+  *AUTOLOAD = \&AutoLoader::AUTOLOAD;
+
+
 =head2 Package Lexicals
 
 Package lexicals declared with C<my> in the main block of a package using
@@ -60,7 +85,8 @@ can also handle multiple packages in a file.
 
 B<AutoLoader> only reads code as it is requested, and in many cases should be
 faster, but requires a machanism like B<AutoSplit> be used to create the
-individual files.
+individual files.  The B<ExtUtils::MakeMaker> will invoke B<AutoSplit>
+automatically if the B<AutoLoader> is used in a module source file.
 
 =head1 CAVEAT
 
@@ -72,27 +98,43 @@ conflicts when used to split a module.
 =cut
 
 AUTOLOAD {
-    my $name = "auto/$AUTOLOAD.al";
-    $name =~ s#::#/#g;
+    my $name;
+    # Braces used to preserve $1 et al.
+    {
+     my ($pkg,$func) = $AUTOLOAD =~ /(.*)::([^:]+)$/;
+     $pkg =~ s#::#/#g;
+     if (defined($name=$INC{"$pkg.pm"}))
+      {
+       $name =~ s#^(.*)$pkg\.pm$#$1auto/$pkg/$func.al#;
+       $name = undef unless (-r $name); 
+      }
+     unless (defined $name)
+      {
+       $name = "auto/$AUTOLOAD.al";
+       $name =~ s#::#/#g;
+      }
+    }
+    my $save = $@;
     eval {require $name};
     if ($@) {
-       # The load might just have failed because the filename was too
-       # long for some old SVR3 systems which treat long names as errors.
-       # If we can succesfully truncate a long name then it's worth a go.
-       # There is a slight risk that we could pick up the wrong file here
-       # but autosplit should have warned about that when splitting.
-       if ($name =~ s/(\w{12,})\.al$/substr($1,0,11).".al"/e){
-           eval {require $name};
-       }
-       elsif ($AUTOLOAD =~ /::DESTROY$/) {
-           # eval "sub $AUTOLOAD {}";
+       if (substr($AUTOLOAD,-9) eq '::DESTROY') {
            *$AUTOLOAD = sub {};
-       }
-       if ($@){
-           $@ =~ s/ at .*\n//;
-           croak $@;
+       } else {
+           # The load might just have failed because the filename was too
+           # long for some old SVR3 systems which treat long names as errors.
+           # If we can succesfully truncate a long name then it's worth a go.
+           # There is a slight risk that we could pick up the wrong file here
+           # but autosplit should have warned about that when splitting.
+           if ($name =~ s/(\w{12,})\.al$/substr($1,0,11).".al"/e){
+               eval {require $name};
+           }
+           if ($@){
+               $@ =~ s/ at .*\n//;
+               croak $@;
+           }
        }
     }
+    $@ = $save;
     $DB::sub = $AUTOLOAD;      # Now debugger know where we are.
     goto &$AUTOLOAD;
 }