# Copyright 2004-2025, Paul Johnson (paul@pjcj.net)

# This software is free.  It is licensed under the same terms as Perl itself.

# The latest version of this software should be available from my homepage:
# https://pjcj.net

package Devel::Cover::DB::Structure;

use strict;
use warnings;

use Carp;
use Digest::MD5;

use Devel::Cover::DB;
use Devel::Cover::DB::IO;
use Devel::Cover::Dumper;

# For comprehensive debug logging.
use constant DEBUG => 0;

our $VERSION = '1.51'; # VERSION
our $AUTOLOAD;

sub new {
  my $class = shift;
  my $self  = {@_};
  bless $self, $class
}

sub DESTROY { }

sub AUTOLOAD {
  my $self = $_[0];
  my $func = $AUTOLOAD;
  $func =~ s/.*:://;
  my ($function, $criterion) = $func =~ /^(add|get)_(.*)/;
  croak "Undefined subroutine $func called"
    unless $criterion && grep $_ eq $criterion, @Devel::Cover::DB::Criteria,
    qw( sub_name file line );
  no strict "refs";
  if ($function eq "get") {
    my $c = $criterion eq "time" ? "statement" : $criterion;
    if (grep $_ eq $c, qw( sub_name file line )) {
      *$func = sub { shift->{$c} };
    } else {
      *$func = sub {
        my $self   = shift;
        my $digest = shift;
        # print STDERR "file: $digest, condition: $c\n";
        for my $fval (values %{ $self->{f} }) {
          return $fval->{$c} if $fval->{digest} eq $digest;
        }
        return
      }
    }
  } else {
    *$func = sub {
      my $self = shift;
      my $file = shift;
      push @{ $self->{f}{$file}{$criterion} }, @_;
    };
  }
  goto &$func
}

sub debuglog {
  my $self = shift;
  my $dir  = "$self->{base}/debuglog";
  unless (mkdir $dir) {
    confess "Can't mkdir $dir: $!" unless -d $dir;
  }

  local $\;
  # One log file per process, as we're potentially dumping out large amounts,
  # and might exceed the atomic write size of the OS
  open my $fh, '>>', "$dir/$$" or confess "Can't open $dir/$$: $!";
  print $fh "----------------" . gmtime() . "----------------\n";
  print $fh ref $_ ? Dumper($_) : $_;
  print $fh "\n";
  close $fh or confess "Can't close $dir/$$: $!";
}

sub add_criteria {
  my $self = shift;
  @{ $self->{criteria} }{@_} = ();
  $self
}

sub criteria {
  my $self = shift;
  keys %{ $self->{criteria} }
}

sub set_subroutine {
  my $self = shift;
  my ($sub_name, $file, $line, $scount)
    = @{$self}{qw( sub_name file line scount )} = @_;

  # When new code is added at runtime, via a string eval in some guise, we
  # need information about where structure information for the subroutine
  # is.  This information is stored in $self->{f}{$file}{start} keyed on the
  # filename, line number, subroutine name and the count, the count being
  # for when there are multiple subroutines of the same name on the same
  # line (such subroutines generally being called BEGIN).

  # print STDERR "set_subroutine start $file:$line $sub_name($scount) ",
  # Dumper $self->{f}{$file}{start};
  $self->{additional} = 0;
  if ($self->reuse($file)) {
    # reusing a structure
    if (exists $self->{f}{$file}{start}{$line}{$sub_name}[$scount]) {
      # sub already exists - normal case
      # print STDERR "reuse $file:$line:$sub_name\n";
      $self->{count}{$_}{$file}
        = $self->{f}{$file}{start}{$line}{$sub_name}[$scount]{$_}
        for $self->criteria;
    } else {
      # sub doesn't exist, for example a conditional C<eval "use M">
      $self->{additional} = 1;
      if (exists $self->{additional_count}{ ($self->criteria)[0] }{$file}) {
        # already had such a sub in module
        # print STDERR "reuse additional $file:$line:$sub_name\n";
        $self->{count}{$_}{$file}
          = $self->{f}{$file}{start}{$line}{$sub_name}[$scount]{$_}
          = ($self->add_count($_))[0]
          for $self->criteria;
      } else {
        # first such a sub in module
        # print STDERR "reuse first $file:$line:$sub_name\n";
        $self->{count}{$_}{$file} = $self->{additional_count}{$_}{$file}
          = $self->{f}{$file}{start}{$line}{$sub_name}[$scount]{$_}
          = $self->{f}{$file}{start}{-1}{"__COVER__"}[$scount]{$_}
          for $self->criteria;
      }
    }
  } else {
    # first time sub seen in new structure
    # print STDERR "new $file:$line:$sub_name\n";
    $self->{count}{$_}{$file}
      = $self->{f}{$file}{start}{$line}{$sub_name}[$scount]{$_}
      = $self->get_count($file, $_)
      for $self->criteria;
  }
  # print STDERR "set_subroutine start $file:$line $sub_name($scount) ",
  # Dumper $self->{f}{$file}{start};
}

sub store_counts {
  my $self = shift;
  my ($file) = @_;
  $self->{count}{$_}{$file} = $self->{f}{$file}{start}{-1}{__COVER__}[0]{$_}
    = $self->get_count($file, $_)
    for $self->criteria;
  # print STDERR "store_counts: ", Dumper $self->{f}{$file}{start};
}

sub reuse {
  my $self = shift;
  my ($file) = @_;
  exists $self->{f}{$file}{start}{-1}{"__COVER__"}
  # TODO - exists $self->{f}{$file}{start}{-1}
}

sub set_file {
  my $self = shift;
  my ($file) = @_;
  $self->{file} = $file;
  my $digest = $self->digest($file);
  if ($digest) {
    # print STDERR "Adding $digest for $file\n";
    $self->{f}{$file}{digest} = $digest;
    push @{ $self->{digests}{$digest} }, $file;
  }
  $digest
}

sub digest {
  my $self = shift;
  my ($file) = @_;

  # print STDERR "Opening $file for MD5 digest\n";

  my $digest;
  if (open my $fh, "<", $file) {
    binmode $fh;
    $digest = Digest::MD5->new->addfile($fh)->hexdigest;
  } else {
    print STDERR "Devel::Cover: Warning: can't open $file "
      . "for MD5 digest: $!\n"
      unless lc $file eq "-e"
      or $Devel::Cover::Silent
      or $file =~ $Devel::Cover::DB::Ignore_filenames;
    # require "Cwd"; print STDERR Carp::longmess("in " . Cwd::cwd());
  }
  $digest
}

sub get_count {
  my $self = shift;
  my ($file, $criterion) = @_;
  $self->{count}{$criterion}{$file}
}

sub add_count {
  my $self = shift;
  # warn Carp::longmess("undefined file") unless defined $self->{file};
  return unless defined $self->{file};  # can happen during self_cover
  my ($criterion) = @_;
  $self->{additional_count}{$criterion}{ $self->{file} }++
    if $self->{additional};
  (
    $self->{count}{$criterion}{ $self->{file} }++,
    !$self->reuse($self->{file}) || $self->{additional},
  )
}

sub delete_file {
  my $self = shift;
  my ($file) = @_;
  delete $self->{f}{$file};
}

# TODO - concurrent runs updating structure?

sub write {
  my $self = shift;
  my ($dir) = @_;
  # print STDERR Dumper $self;
  $dir .= "/structure";
  unless (mkdir $dir) {
    confess "Can't mkdir $dir: $!" unless -d $dir;
  }
  chmod 0777, $dir if $self->{loose_perms};
  for my $file (sort keys %{ $self->{f} }) {
    $self->{f}{$file}{file} = $file;
    my $digest = $self->{f}{$file}{digest};
    $digest = $1 if defined $digest && $digest =~ /(.*)/;  # ie tainting
    unless ($digest) {
      print STDERR "Can't find digest for $file"
        unless $Devel::Cover::Silent
        || $file =~ $Devel::Cover::DB::Ignore_filenames
        || ($Devel::Cover::Self_cover && $file =~ q|/Devel/Cover[./]|);
      next;
    }
    my $df_final = "$dir/$digest";
    my $df_temp  = "$dir/.$digest.$$";
    # TODO - determine if Structure has changed to save writing it
    # my $f = $df; my $n = 1; $df = $f . "." . $n++ while -e $df;
    my $io = Devel::Cover::DB::IO->new;
    $io->write($self->{f}{$file}, $df_temp);  # unless -e $df;
    unless (rename $df_temp, $df_final) {
      unless ($Devel::Cover::Silent) {
        if (-e $df_final) {
          print STDERR "Can't rename $df_temp to $df_final "
            . "(which exists): $!";
          $self->debuglog(
            "Can't rename $df_temp to $df_final " . "(which exists): $!")
            if DEBUG;
        } else {
          print STDERR "Can't rename $df_temp to $df_final: $!";
          $self->debuglog("Can't rename $df_temp to $df_final: $!") if DEBUG;
        }
      }
      unless (unlink $df_temp) {
        print STDERR "Can't remove $df_temp after failed rename: $!"
          unless $Devel::Cover::Silent;
        $self->debuglog("Can't remove $df_temp after failed rename: $!")
          if DEBUG;
      }
    }
  }
}

sub read {

  my $self     = shift;
  my ($digest) = @_;
  my $file     = "$self->{base}/structure/$digest";
  my $io       = Devel::Cover::DB::IO->new;
  my $s        = eval { $io->read($file) };

  if ($@ or !$s) {
    $self->debuglog("read retrieve $file failed: $@") if DEBUG;
    die $@;
  }
  if (DEBUG) {
    foreach my $key (qw(file digest)) {
      if (!defined $s->{$key}) {
        $self->debuglog("retrieve $file had no $key entry. Got:\n", $s);
      }
    }
  }
  my $d = $self->digest($s->{file});
  # print STDERR "reading $digest from $file: ", Dumper $s;
  if (!$d) {
    # No digest implies that we can't read the file. Likely this is because
    # it's stored with a relative path. In which case, it's not valid to
    # assume that the file has been changed, and hence that we need to
    # "update" the structure database on disk.
  } elsif ($d eq $s->{digest}) {
    $self->{f}{ $s->{file} } = $s;
  } else {
    print STDERR "Devel::Cover: Deleting old coverage ",
      "for changed file $s->{file}\n";
    if (unlink $file) {
      $self->debuglog(
        "Deleting old coverage $file for changed "
          . "$s->{file} $s->{digest} vs $d. Got:\n",
        $s, "Have:\n", $self->{f}{$file}
      ) if DEBUG;
    } else {
      print STDERR "Devel::Cover: can't delete $file: $!\n";
      $self->debuglog(
        "Failed to delete coverage $file for changed "
          . "$s->{file} ($!) $s->{digest} vs $d. Got:\n",
        $s, "Have:\n", $self->{f}{$file}
      ) if DEBUG;
    }
  }
  $self
}

sub read_all {
  my ($self) = @_;
  my $dir = $self->{base};
  $dir .= "/structure";
  opendir D, $dir or return;
  for my $d (sort grep $_ !~ /\./, readdir D) {
    $d = $1 if $d =~ /(.*)/;  # Die tainting
    $self->read($d);
  }
  closedir D or die "Can't closedir $dir: $!";
  $self
}

sub merge {
  my $self = shift;
  my ($from) = @_;
  Devel::Cover::DB::_merge_hash($self->{f}, $from->{f}, "noadd");
}

1

__END__

=head1 NAME

Devel::Cover::DB::Structure - Internal: abstract structure of a source file

=head1 VERSION

version 1.51

=head1 SYNOPSIS

 use Devel::Cover::DB::Structure;

=head1 DESCRIPTION

=head1 SEE ALSO

 Devel::Cover
 Devel::Cover::DB

=head1 METHODS

=head1 BUGS

Huh?

=head1 LICENCE

Copyright 2004-2025, Paul Johnson (paul@pjcj.net)

This software is free.  It is licensed under the same terms as Perl itself.

The latest version of this software should be available from my homepage:
https://pjcj.net

=cut
