package Test::Valgrind::Suppressions;

use strict;
use warnings;

=head1 NAME

Test::Valgrind::Suppressions - Generate suppressions for given tool and command.

=head1 VERSION

Version 1.19

=cut

our $VERSION = '1.19';

=head1 DESCRIPTION

This module is an helper for generating suppressions.

=cut

use base qw<Test::Valgrind::Carp>;

=head1 METHODS

=head2 C<generate>

    Test::Valgrind::Suppressions->generate(
     tool    => $tool,
     command => $command,
     target  => $target,
    );

Generates suppressions for the command C<< $command->new_trainer >> and the tool C<< $tool->new_trainer >>, and writes them in the file specified by C<$target>.
The action used behind the scenes is L<Test::Valgrind::Action::Suppressions>.

Returns the status code.

=cut

sub generate {
 my $self = shift;

 my %args = @_;

 my $cmd = delete $args{command};
 unless (ref $cmd) {
  require Test::Valgrind::Command;
  $cmd = Test::Valgrind::Command->new(
   command => $cmd,
   args    => [ ],
  );
 }
 $cmd = $cmd->new_trainer;
 return unless defined $cmd;

 my $tool = delete $args{tool};
 unless (ref $tool) {
  require Test::Valgrind::Tool;
  $tool = Test::Valgrind::Tool->new(tool => $tool);
 }
 $tool = $tool->new_trainer;
 return unless defined $tool;

 my $target = delete $args{target};
 $self->_croak('Invalid target') unless $target and not ref $target;

 require Test::Valgrind::Action;
 my $action = Test::Valgrind::Action->new(
  action => 'Suppressions',
  target => $target,
  name   => 'PerlSuppression',
 );

 require Test::Valgrind::Session;
 my $sess = Test::Valgrind::Session->new(
  min_version => $tool->requires_version,
 );

 eval {
  $sess->run(
   command => $cmd,
   tool    => $tool,
   action  => $action,
  );
 };
 $self->_croak($@) if $@;

 my $status = $sess->status;
 $status = 255 unless defined $status;

 return $status;
}

=head2 C<maybe_generalize>

    my $mangled_suppression = Test::Valgrind::Suppressions->maybe_generalize(
     $session,
     $suppression,
    );

Removes all wildcard frames at the end of the suppression.
It also replaces sequences of wildcard frames by C<'...'> when C<valgrind> C<3.4.0> or higher is used.
Returns the mangled suppression.

=cut

sub maybe_generalize {
 shift;

 my ($sess, $supp) = @_;

 1 while $supp =~ s/[^\r\n]*:\s*\*\s*$//;

 # With valgrind 3.4.0, we can replace unknown series of frames by '...'
 my $can_ellipsis = $sess->version >= '3.4.0';

 my $did_length_check;

 ELLIPSIS: {
  if ($can_ellipsis) {
   $supp .= "...\n";
   $supp =~ s/(?:^\s*(?:\.{3}|\*:\S*|obj:\*)\s*(?:\n|\z))+/...\n/mg;
  }

  last if $did_length_check++;

  my $frames_count =()= $supp =~ m/^(?:(?:obj|fun|\*):|\.{3}\s*$)/mg;
  if ($frames_count > 24) {
   # Keep only 24 frames, and even sacrifice one more if we can do ellipsis.
   my $last = $can_ellipsis ? 23 : 24;
   my $len  = length $supp;
   $supp    =~ m/^(?:(?:obj|fun|\*):\S*|\.{3})\s*\n/mg for 1 .. $last;
   my $p    = pos $supp;
   substr $supp, $p, $len - $p, '';
   redo ELLIPSIS if $can_ellipsis;
  }
 }

 $supp;
}

=head2 C<maybe_z_demangle>

    my $demangled_symbol = Test::Valgrind::Suppressions->maybe_z_demangle(
     $symbol,
    );

If C<$symbol> is Z-encoded as described in C<valgrind>'s F<include/pub_tool_redir.h>, extract and decode its function name part.
Otherwise, C<$symbol> is returned as is.

This routine follows C<valgrind>'s F<coregrind/m_demangle/demangle.c:maybe_Z_demangle>.

=cut

my %z_escapes = (
 a => '*',
 c => ':',
 d => '.',
 h => '-',
 p => '+',
 s => ' ',
 u => '_',
 A => '@',
 D => '$',
 L => '(',
 R => ')',
 Z => 'Z',
);

sub maybe_z_demangle {
 my ($self, $sym) = @_;

 $sym =~ s/^_vg[rwn]Z([ZU])_// or return $sym;

 my $fn_is_encoded = $1 eq 'Z';

 $sym =~ /^VG_Z_/ and $self->_croak('Symbol with a "VG_Z_" prefix is invalid');
 $sym =~ s/^[^_]*_//
                   or $self->_croak('Symbol doesn\'t contain a function name');

 if ($fn_is_encoded) {
  $sym =~ s/Z(.)/
   my $c = $z_escapes{$1};
   $self->_croak('Invalid escape sequence') unless defined $c;
   $c;
  /ge;
 }

 $self->_croak('Empty symbol') unless length $sym;

 return $sym;
}

=head1 SEE ALSO

L<Test::Valgrind>, L<Test::Valgrind::Command>, L<Test::Valgrind::Tool>, L<Test::Valgrind::Action::Suppressions>.

=head1 AUTHOR

Vincent Pit, C<< <perl at profvince.com> >>, L<http://www.profvince.com>.

You can contact me by mail or on C<irc.perl.org> (vincent).

=head1 BUGS

Please report any bugs or feature requests to C<bug-test-valgrind-suppressions at rt.cpan.org>, or through the web interface at L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Test-Valgrind>.
I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

=head1 SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc Test::Valgrind::Suppressions

=head1 COPYRIGHT & LICENSE

Copyright 2008,2009,2010,2011,2013,2015,2016 Vincent Pit, all rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

=cut

1; # End of Test::Valgrind::Suppressions
