Item14152: First class replacement implementation.

Implemented with Moo::Role create_class_with_roles. Foswiki::Config has
been choosen as the first victim.  An example extension class
Foswiki::Extension::Sample::Class overrides its assignGLOB() method and
instead of aliasing %Foswiki::cfg into $Foswiki::app->cfg->data it ties the
global.

This implementation is only an example. The module will later be deleted
from the repository. The real implementation would make sense if we decide
to move the config into a database, for example. In this case direct
references to Foswiki::Config data attribute must be replaced with calls to
get/set/delete/etc. method calls.

core/lib/Foswiki/App.pm

@@ -23,6 +23,7 @@ use Storable qw(dclone);
 # shortcut functions. Must be replaced with something more reasonable.
 use CGI ();
 use Compress::Zlib;
+use Foswiki::Extensions;
 use Foswiki::Engine;
 use Foswiki::Templates;
 use Foswiki::Exception;
@@ -77,6 +78,7 @@ has cache => (
 );
 
 =begin TML
+
 ---++ ObjectAttribute cfg
 
 This attribute stores application configuration object - a =Foswiki::Config=
@@ -610,7 +612,7 @@ sub create {
     my $this  = shift;
     my $class = shift;
 
-    $class = ref($class) if ref($class);
+    $class = $this->extensions->mapClass($class);
 
     Foswiki::load_class($class);
 
@@ -1542,7 +1544,9 @@ sub _prepareUser {
 
 sub _prepareExtensions {
     my $this = shift;
-    return $this->create('Foswiki::Extensions');
+
+    # Don't use create() here because the latter depends on extensions.
+    return Foswiki::Extensions->new( app => $this );
 }
 
 # If the X-Foswiki-Tickle header is present, this request is an attempt to
@@ -2241,7 +2245,7 @@ sub eachMembership {
 
 =begin TML
 
----+++ eachGroupMember($group) -> $iterator
+---+++ ObjectMethod eachGroupMember($group) -> $iterator
 Get an iterator over all the members of the named group. Returns undef if
 $group is not a valid group.  Nested groups are expanded unless the
 expand option is set to false.
@@ -2282,7 +2286,7 @@ sub eachGroupMember {
 
 =begin TML
 
----+++ addUserToGroup( $id, $group, $create ) -> $boolean
+---+++ ObjectMethod addUserToGroup( $id, $group, $create ) -> $boolean
 
    * $id can be a login name or a WikiName
 
@@ -2304,7 +2308,7 @@ sub addUserToGroup {
 
 =begin TML
 
----+++ removeUserFromGroup( $group, $id ) -> $boolean
+---+++ ObjectMethod removeUserFromGroup( $group, $id ) -> $boolean
 
    * $id can be a login name or a WikiName
 

core/lib/Foswiki/Extension/Empty.pm

@@ -1,3 +1,5 @@
+# See bottom of file for license and copyright information
+
 package Foswiki::Extension::Empty;
 
 use Foswiki::Class qw(extension);
@@ -11,3 +13,21 @@ extAfter qw(Sample);
 extBefore qw(Test1 Foswiki::Extension::Test2);
 
 1;
+__END__
+Foswiki - The Free and Open Source Wiki, http://foswiki.org/
+
+Copyright (C) 2016 Foswiki Contributors. Foswiki Contributors
+are listed in the AUTHORS file in the root of this distribution.
+NOTE: Please extend that file, not this notice.
+
+This program is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; either version 2
+of the License, or (at your option) any later version. For
+more details read LICENSE in the root of this distribution.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+As per the GPL, removal of this notice is prohibited.

core/lib/Foswiki/Extension/Sample.pm

@@ -1,3 +1,4 @@
+# See bottom of file for license and copyright information
 
 package Foswiki::Extension::Sample;
 
@@ -11,8 +12,26 @@ plugBefore 'Foswiki::Exception::transmute' => sub {
 
 };
 
-extClass 'Foswiki::Logger', 'Foswiki::Extension::Sample::Logger';
+extClass 'Foswiki::Config', 'Foswiki::Extension::Sample::Config';
 
 extBefore qw(Empty);
 
 1;
+__END__
+Foswiki - The Free and Open Source Wiki, http://foswiki.org/
+
+Copyright (C) 2016 Foswiki Contributors. Foswiki Contributors
+are listed in the AUTHORS file in the root of this distribution.
+NOTE: Please extend that file, not this notice.
+
+This program is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; either version 2
+of the License, or (at your option) any later version. For
+more details read LICENSE in the root of this distribution.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+As per the GPL, removal of this notice is prohibited.

core/lib/Foswiki/Extension/Sample/Config.pm

@@ -0,0 +1,116 @@
+# See bottom of file for license and copyright information
+
+package Foswiki::Extension::Sample::TiedConfig;
+use Assert;
+
+sub TIEHASH {
+    my $class = shift;
+    my ($cfgObject) = @_;
+
+    my $thisHash = { cfg => $cfgObject, };
+
+    return bless $thisHash, $class;
+}
+
+sub FETCH {
+    my ( $this, $key ) = @_;
+    ASSERT( defined $this->{cfg} ) if DEBUG;
+    $this->trace("FETCH{$key}");
+    return $this->{cfg}->data->{$key};
+}
+
+sub STORE {
+    my ( $this, $key, $value ) = @_;
+    ASSERT( defined $this->{cfg} ) if DEBUG;
+    $this->trace("STORE{$key}");
+    $this->{cfg}->data->{$key} = $value;
+}
+
+sub DELETE {
+    my ( $this, $key ) = @_;
+    ASSERT( defined $this->{cfg} ) if DEBUG;
+    $this->trace("DELETE{$key}");
+    delete $this->{cfg}->data->{$key};
+}
+
+sub CLEAR {
+    my ($this) = @_;
+    ASSERT( defined $this->{cfg} ) if DEBUG;
+    $this->{cfg}->clear_data;
+}
+
+sub EXISTS {
+    my ( $this, $key ) = @_;
+    ASSERT( defined $this->{cfg} ) if DEBUG;
+    return exists $this->{cfg}->data->{$key};
+}
+
+sub FIRSTKEY {
+    my ($this) = @_;
+    ASSERT( defined $this->{cfg} ) if DEBUG;
+    my $_ignore = keys %{ $this->{cfg}->data };
+    return each %{ $this->{cfg}->data };
+}
+
+sub NEXTKEY {
+    my ($this) = @_;
+    ASSERT( defined $this->{cfg} ) if DEBUG;
+    return each %{ $this->{cfg}->data };
+}
+
+sub SCALAR {
+    my ($this) = @_;
+    ASSERT( defined $this->{cfg} ) if DEBUG;
+    return scalar %{ $this->{cfg}->data };
+}
+
+sub UNTIE {
+    my ($this) = @_;
+
+    undef $this->{cfg};
+}
+
+sub setTrace {
+    my $this = shift;
+    $this->{_trace} = shift;
+}
+
+sub trace {
+    my $this = shift;
+    if ( $this->{_trace} ) {
+        say STDERR @_;
+    }
+}
+
+package Foswiki::Extension::Sample::Config;
+
+use Moo::Role;
+
+around assignGLOB => sub {
+    my $orig = shift;
+    my $this = shift;
+
+    say STDERR "This is a replacement assignGLOB method.";
+
+    tie %Foswiki::cfg, 'Foswiki::Extension::Sample::TiedConfig', $this;
+};
+
+1;
+__END__
+Foswiki - The Free and Open Source Wiki, http://foswiki.org/
+
+Copyright (C) 2016 Foswiki Contributors. Foswiki Contributors
+are listed in the AUTHORS file in the root of this distribution.
+NOTE: Please extend that file, not this notice.
+
+This program is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; either version 2
+of the License, or (at your option) any later version. For
+more details read LICENSE in the root of this distribution.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+As per the GPL, removal of this notice is prohibited.

core/lib/Foswiki/Extensions.pm

@@ -133,10 +133,11 @@ sub BUILD {
     say STDERR "Initializing extensions" if DEBUG;
 
     $this->load_extensions;
-    $this->registeredClasses;
 
-    say STDERR "Ext sub classes: ", Dumper( \%extSubClasses );
-    say STDERR "Ext deps: ",        Dumper( \%extDeps );
+    #$this->registeredClasses;
+    #
+    #say STDERR "Ext sub classes: ", Dumper( \%extSubClasses );
+    #say STDERR "Ext deps: ",        Dumper( \%extDeps );
 }
 
 sub normalizeExtName {
@@ -391,9 +392,28 @@ sub disableExtension {
 
 =begin TML
 
----++ ObjectMethod listDisabledExtensions => @list
+---++ ObjectMethod mapClass($class) => $replacement
 
-Returns a list of extensions disabled for this installation or host.
+Maps a core class name into replacement class name.
+
+=cut
+
+sub mapClass {
+    my $this = shift;
+    my ($class) = @_;
+
+    $class = ref($class) || $class;
+
+    my $replClass = $this->registeredClasses->{$class};
+    return $replClass || $class;
+}
+
+=begin TML
+
+---++ ObjectMethod prepareDisabledExtensions => \%disabled
+
+Returns extensions disabled for this installation or host. %disabled hash keys
+are extension names, values are text reasons for disabling the extension.
 
 =cut
 
@@ -462,15 +482,33 @@ sub prepareRegisteredClasses {
         }
     }
 
-    foreach my $extName ( @{ $this->orderedList } ) {
+    # Build inheritance order. Use reverse to conform with the way overriden
+    # methods are getting called.
+    my %inheritance;
+    foreach my $extName ( reverse @{ $this->orderedList } ) {
         foreach my $coreClass ( keys %{ $ext2class{$extName} } ) {
-            push @{ $classMap{$coreClass} }, $ext2class{$extName}{$coreClass};
+            push @{ $inheritance{$coreClass} },
+              $ext2class{$extName}{$coreClass};
         }
     }
 
+    # Build actual replacement classes.
+    foreach my $coreClass ( keys %inheritance ) {
+        ( my $crypticName = $coreClass ) =~ s/::/__/;
+        $classMap{$coreClass} =
+          Moo::Role->create_class_with_roles( $coreClass,
+            @{ $inheritance{$coreClass} } );
+    }
+
     return \%classMap;
 }
 
+=begin TML
+
+---++ Static methods
+
+=cut
+
 sub registerSubClass {
     my ( $extModule, $class, $subClass ) = @_;
 
@@ -500,6 +538,18 @@ sub isRegistered {
     return $registeredModules{$extModule} // 0;
 }
 
+sub genClassName {
+    my ($nameTmpl) = @_;
+
+    state $seqNum = 0;
+
+    my $nameFmt = $nameTmpl // 'Foswiki::Class::_AutoXXXXX';
+
+    $nameFmt =~ s/(X{3,})/"%0" . length($1) . "d"/e;
+
+    return sprintf( $nameFmt, $seqNum );
+}
+
 1;
 __END__
 Foswiki - The Free and Open Source Wiki, http://foswiki.org/

core/lib/Foswiki/Logger/Compatibility.pm

@@ -16,8 +16,7 @@ BEGIN {
 
 # Internal class for Logfile iterators.
 # So we don't break encapsulation of file handles.  Open / Close in same file.
-use Moo;
-use namespace::clean;
+use Foswiki::Class;
 extends qw(Foswiki::Iterator::EventIterator);
 
 has logLocked => (

core/lib/Foswiki/Logger/PlainFile.pm

@@ -15,8 +15,7 @@ BEGIN {
 
 # Internal class for Logfile iterators.
 # So we don't break encapsulation of file handles.  Open / Close in same file.
-use Moo;
-use namespace::clean;
+use Foswiki::Class;
 extends qw(Foswiki::Iterator::EventIterator);
 
 has handle => ( is => 'rw', );