From: Peter Rabbitson <ribasushi@cpan.org>
Date: Mon, 27 Jan 2014 17:54:30 +0000 (+0100)
Subject: Factor out the symtable walker, no functional changes but much reshuffling
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=a42634cdbf7e969bb9133ff71d2bc2666003d53a;p=dbsrgits%2FDBIx-Class-Historic.git

Factor out the symtable walker, no functional changes but much reshuffling
---

diff --git a/t/lib/DBICTest/Util/LeakTracer.pm b/t/lib/DBICTest/Util/LeakTracer.pm
index 58790e4..48ec21d 100644
--- a/t/lib/DBICTest/Util/LeakTracer.pm
+++ b/t/lib/DBICTest/Util/LeakTracer.pm
@@ -109,18 +109,19 @@ sub visit_refs {
 
   my $visited_cnt = '0E0';
   for my $i (0 .. $#{$args->{refs}} ) {
-    next if isweak($args->{refs}[$i]);
 
-    my $r = $args->{refs}[$i];
+    next unless length ref $args->{refs}[$i]; # not-a-ref
 
-    next unless length ref $r;
+    my $addr = hrefaddr $args->{refs}[$i];
 
     # no diving into weakregistries
-    next if $reg_of_regs{hrefaddr $r};
-
-    next if $args->{seen_refs}{my $dec_addr = Scalar::Util::refaddr($r)}++;
+    next if $reg_of_regs{$addr};
 
+    next if $args->{seen_refs}{$addr}++;
     $visited_cnt++;
+
+    my $r = $args->{refs}[$i];
+
     $args->{action}->($r) or next;
 
     # This may end up being necessarry some day, but do not slow things
@@ -129,9 +130,10 @@ sub visit_refs {
     #  $visited_cnt += visit_refs({ %$args, refs => [ $t ] });
     #}
 
+    my $type = reftype $r;
+
     local $@;
     eval {
-      my $type = reftype $r;
       if ($type eq 'HASH') {
         $visited_cnt += visit_refs({ %$args, refs => [ map {
           ( !isweak($r->{$_}) ) ? $r->{$_} : ()
@@ -156,55 +158,62 @@ sub visit_refs {
   $visited_cnt;
 }
 
-sub assert_empty_weakregistry {
-  my ($weak_registry, $quiet) = @_;
-
-  # in case we hooked bless any extra object creation will wreak
-  # havoc during the assert phase
-  local *CORE::GLOBAL::bless;
-  *CORE::GLOBAL::bless = sub { CORE::bless( $_[0], (@_ > 1) ? $_[1] : caller() ) };
+sub visit_namespaces {
+  my $args = { (ref $_[0]) ? %{$_[0]} : @_ };
 
-  croak 'Expecting a registry hashref' unless ref $weak_registry eq 'HASH';
+  my $visited = 1;
 
-  defined $weak_registry->{$_}{weakref} or delete $weak_registry->{$_}
-    for keys %$weak_registry;
+  $args->{package} ||= '::';
+  $args->{package} = '::' if $args->{package} eq 'main';
 
-  return unless keys %$weak_registry;
+  if ( $args->{action}->($args->{package}) ) {
 
-  my $tb = eval { Test::Builder->new }
-    or croak "Calling assert_empty_weakregistry in $0 without a loaded Test::Builder makes no sense";
+    my $base = $args->{package};
+    $base = '' if $base eq '::';
 
-  for my $addr (keys %$weak_registry) {
-    $weak_registry->{$addr}{display_name} = join ' | ', (
-      sort
-        { length $a <=> length $b or $a cmp $b }
-        keys %{$weak_registry->{$addr}{slot_names}}
-    );
 
-    $tb->BAILOUT("!!!! WEAK REGISTRY SLOT $weak_registry->{$addr}{display_name} IS NOT A WEAKREF !!!!")
-      if defined $weak_registry->{$addr}{weakref} and ! isweak( $weak_registry->{$addr}{weakref} );
+    $visited += visit_namespaces({ %$args, package => $_ }) for map
+      { $_ =~ /(.+?)::$/ && "${base}::$1" }
+      grep
+        { $_ =~ /(?<!^main)::$/ }
+        do {  no strict 'refs'; keys %{ $base . '::'} }
   }
 
-  # compile a list of refs stored as globals (possibly even catching
-  # class data in the form of method closures), so we can skip them
-  # further on
-  my ($seen_refs, $classdata_refs) = ({}, undef);
+  return $visited;
+}
+
+# compiles a list of addresses stored as globals (possibly even catching
+# class data in the form of method closures), so we can skip them further on
+sub symtable_referenced_addresses {
+
+  my $refs_per_pkg;
+
+  my $dummy_addresslist;
+
+  my $seen_refs = {};
+  visit_namespaces(
+    action => sub {
 
-  # the walk is very expensive - if we are $quiet (running in an END block)
-  # we do not really need to be too thorough
-  unless ($quiet) {
-    my ($symwalker, $symcounts);
-    $symwalker = sub {
       no strict 'refs';
-      my $pkg = shift || '::';
 
-      # any non-weak globals are "clasdata" in all possible sense
-      #
+      my $pkg = shift;
+      $pkg = '' if $pkg eq '::';
+      $pkg .= '::';
+
       # the unless regex at the end skips some dangerous namespaces outright
       # (but does not prevent descent)
-      $symcounts->{$pkg} += visit_refs (
+      $refs_per_pkg->{$pkg} += visit_refs (
         seen_refs => $seen_refs,
-        action => sub { ++$classdata_refs->{hrefaddr $_[0]} },
+
+        # FIXME FIXME FIXME
+        # This is so damn odd - if we feed a constsub {1} (or in fact almost
+        # anything other than the actionsub below, any scalarref will show
+        # up as a leak, trapped by... something...
+        # Ideally we should be able to const this to sub{1} and just return
+        # $seen_refs (in fact it is identical to the dummy list at the end of
+        # a run here). Alas this doesn't seem to work, so punt for now...
+        action => sub { ++$dummy_addresslist->{ hrefaddr $_[0] } },
+
         refs => [ map { my $sym = $_;
           # *{"$pkg$sym"}{CODE} won't simply work - MRO-cached CVs are invisible there
           ( CV_TRACING ? Class::MethodCache::get_cv("${pkg}$sym") : () ),
@@ -212,31 +221,66 @@ sub assert_empty_weakregistry {
           ( defined *{"$pkg$sym"}{SCALAR} and length ref ${"$pkg$sym"} and ! isweak( ${"$pkg$sym"} ) )
             ? ${"$pkg$sym"} : ()
           ,
+
           ( map {
             ( defined *{"$pkg$sym"}{$_} and ! isweak(defined *{"$pkg$sym"}{$_}) )
               ? *{"$pkg$sym"}{$_}
               : ()
           } qw(HASH ARRAY IO GLOB) ),
+
         } keys %$pkg ],
       ) unless $pkg =~ /^ :: (?:
         DB | next | B | .+? ::::ISA (?: ::CACHE ) | Class::C3
       ) :: $/x;
+    }
+  );
 
-      $symwalker->("${pkg}$_") for grep { $_ =~ /(?<!^main)::$/ } keys %$pkg;
-    };
+#  use Devel::Dwarn;
+#  Ddie [ map
+#    { { $_ => $refs_per_pkg->{$_} } }
+#    sort
+#      {$refs_per_pkg->{$a} <=> $refs_per_pkg->{$b} }
+#      keys %$refs_per_pkg
+#  ];
+
+  $seen_refs;
+}
+
+sub assert_empty_weakregistry {
+  my ($weak_registry, $quiet) = @_;
+
+  # in case we hooked bless any extra object creation will wreak
+  # havoc during the assert phase
+  local *CORE::GLOBAL::bless;
+  *CORE::GLOBAL::bless = sub { CORE::bless( $_[0], (@_ > 1) ? $_[1] : caller() ) };
+
+  croak 'Expecting a registry hashref' unless ref $weak_registry eq 'HASH';
+
+  defined $weak_registry->{$_}{weakref} or delete $weak_registry->{$_}
+    for keys %$weak_registry;
+
+  return unless keys %$weak_registry;
 
-    $symwalker->();
+  my $tb = eval { Test::Builder->new }
+    or croak "Calling assert_empty_weakregistry in $0 without a loaded Test::Builder makes no sense";
 
-#    use Devel::Dwarn;
-#    Ddie [ map
-#      { { $_ => $symcounts->{$_} } }
-#      sort
-#        {$symcounts->{$a} <=> $symcounts->{$b} }
-#        keys %$symcounts
-#    ];
+  for my $addr (keys %$weak_registry) {
+    $weak_registry->{$addr}{display_name} = join ' | ', (
+      sort
+        { length $a <=> length $b or $a cmp $b }
+        keys %{$weak_registry->{$addr}{slot_names}}
+    );
+
+    $tb->BAILOUT("!!!! WEAK REGISTRY SLOT $weak_registry->{$addr}{display_name} IS NOT A WEAKREF !!!!")
+      if defined $weak_registry->{$addr}{weakref} and ! isweak( $weak_registry->{$addr}{weakref} );
+  }
+
+  # the walk is very expensive - if we are $quiet (running in an END block)
+  # we do not really need to be too thorough
+  unless ($quiet) {
+    delete $weak_registry->{$_} for keys %{ symtable_referenced_addresses() };
   }
 
-  delete $weak_registry->{$_} for keys %$classdata_refs;
 
   for my $addr (sort { $weak_registry->{$a}{display_name} cmp $weak_registry->{$b}{display_name} } keys %$weak_registry) {