#This script is designed to run with Understand - CodeCheck
use base qw(Understand::Codecheck);
use strict;


use Codecheck::Libraries::InfoSiftr qw(resolveTypedefs);

use constant ERR1 => 'Violation: union used for "%1".';
use constant ERR2 => 'Violation: union "%1" is invalid.';

sub register_tr_text {
	my $check = shift;
	$check->add_tr_text(ERR1);
	$check->add_tr_text(ERR2);
}

sub name { '9-5-1 Unions shall not be used' }

sub description { '9-5-1 (Required) Unions shall not be used.' }

sub detailed_description { <<'END_DESC'
<p><b>Rationale</b><br>
The use of unions to access an object in different ways may result in the data being misinterpreted. 
Therefore, this rule prohibits the use of unions for any purpose.
<p>It is recognized nonetheless that there are situations in which the careful use of unions is desirable 
in	constructing	an	efficient	implementation.	In	such	situations,	deviations	to	this	rule	are	considered	
acceptable provided that all relevant implementation-defined behaviour is documented. This might 
be achieved in practice by referencing the implementation section of the compiler manuals from 
the design documentation.</p>
<b>Example</b><pre style="margin-top:0;padding-top:0;">
namespace NS1 
{ 
                 // Compliant - no union 
}
namespace NS2 
{ 
   union U1     // Non-compliant – union 
   { 
      int32_t   i; 
      float32_t j; 
   }; 
}</pre>
END_DESC
}

sub test_language {
	my $language = shift;
	return $language eq 'C++';
}

sub test_entity { 0 }

sub test_global { 1 }

sub define_options { }

sub check {
	my $check = shift;
   my %typelist;
  
	foreach my $file ($check->get_files) {
   my $type;
	
	foreach my $ref ($file->filerefs('define, declare', 'union', 0)) {
		$check->violation($ref->ent, $ref->file, $ref->line, $ref->column, ERR2, $ref->ent->longname);
	}
	
	foreach my $ref ($file->filerefs('define, declare', 'object, typedef', 0)) {
		if($typelist{$ref->ent->type}){
      $type = $typelist{$ref->ent->type};
     }
    else{
      $type = resolveTypedefs($ref->ent->type, $check->db);
      $typelist{$ref->ent->type} = $type;
    }
		next unless $type =~ m! \b union \b !x;
		
		$check->violation($ref->ent, $ref->file, $ref->line, $ref->column, ERR1, $ref->ent->longname);
	}
	}
	return;
}