template.pm

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    $self->_commit_to_file_cache();
  }
  $self->_commit_to_cache() if (($options->{cache}
                                and not $options->{shared_cache}
				and not $options->{file_cache}) or
                                ($options->{double_cache}) or
				($options->{double_file_cache}));
}

# Caching subroutines - they handle getting and validating cache
# records from either the in-memory or shared caches.

# handles the normal in memory cache
use vars qw( %CACHE );
sub _fetch_from_cache {
  my $self = shift;
  my $options = $self->{options};
  
  # return if there's no cache entry for this filename
  return unless exists($options->{filename});
  my $filepath = $self->_find_file($options->{filename});
  return unless (defined($filepath) and
                 exists $CACHE{$filepath});
  
  $options->{filepath} = $filepath;

  # validate the cache
  my $mtime = $self->_mtime($filepath);  
  if (defined $mtime) {
    # return if the mtime doesn't match the cache
    if (defined($CACHE{$filepath}{mtime}) and 
        ($mtime != $CACHE{$filepath}{mtime})) {
      $options->{cache_debug} and 
        print STDERR "CACHE MISS : $filepath : $mtime\n";
      return;
    }

    # if the template has includes, check each included file's mtime
    # and return if different
    if (exists($CACHE{$filepath}{included_mtimes})) {
      foreach my $filename (keys %{$CACHE{$filepath}{included_mtimes}}) {
        next unless 
          defined($CACHE{$filepath}{included_mtimes}{$filename});
        
        my $included_mtime = (stat($filename))[9];
        if ($included_mtime != $CACHE{$filepath}{included_mtimes}{$filename}) {
          $options->{cache_debug} and 
            print STDERR "### HTML::Template Cache Debug ### CACHE MISS : $filepath : INCLUDE $filename : $included_mtime\n";
          
          return;
        }
      }
    }
  }

  # got a cache hit!
  
  $options->{cache_debug} and print STDERR "### HTML::Template Cache Debug ### CACHE HIT : $filepath\n";
      
  $self->{param_map} = $CACHE{$filepath}{param_map};
  $self->{parse_stack} = $CACHE{$filepath}{parse_stack};
  exists($CACHE{$filepath}{included_mtimes}) and
    $self->{included_mtimes} = $CACHE{$filepath}{included_mtimes};

  # clear out values from param_map from last run
  $self->_normalize_options();
  $self->clear_params();
}

sub _commit_to_cache {
  my $self = shift;
  my $options = $self->{options};

  my $filepath = $options->{filepath};
  if (not defined $filepath) {
    $filepath = $self->_find_file($options->{filename});
    confess("HTML::Template->new() : Cannot open included file $options->{filename} : file not found.")
      unless defined($filepath);
    $options->{filepath} = $filepath;   
  }

  $options->{cache_debug} and print STDERR "### HTML::Template Cache Debug ### CACHE LOAD : $filepath\n";
    
  $options->{blind_cache} or
    $CACHE{$filepath}{mtime} = $self->_mtime($filepath);
  $CACHE{$filepath}{param_map} = $self->{param_map};
  $CACHE{$filepath}{parse_stack} = $self->{parse_stack};
  exists($self->{included_mtimes}) and
    $CACHE{$filepath}{included_mtimes} = $self->{included_mtimes};
}

# generates MD5 from filepath to determine filename for cache file
sub _get_cache_filename {
  my ($self, $filepath) = @_;

  # hash the filename ...
  my $hash = Digest::MD5->md5_hex($filepath);
  
  # ... and build a path out of it.  Using the first two charcters
  # gives us 255 buckets.  This means you can have 255,000 templates
  # in the cache before any one directory gets over a few thousand
  # files in it.  That's probably pretty good for this planet.  If not
  # then it should be configurable.
  if (wantarray) {
    return (substr($hash,0,2), substr($hash,2))
  } else {
    return File::Spec->join($self->{options}{file_cache_dir}, 
                            substr($hash,0,2), substr($hash,2));
  }
}

# handles the file cache
sub _fetch_from_file_cache {
  my $self = shift;
  my $options = $self->{options};
  return unless exists($options->{filename});
  
  # return if there's no cache entry for this filename
  my $filepath = $self->_find_file($options->{filename});
  return unless defined $filepath;
  my $cache_filename = $self->_get_cache_filename($filepath);
  return unless -e $cache_filename;
  
  eval {
    $self->{record} = Storable::lock_retrieve($cache_filename);
  };
  croak("HTML::Template::new() - Problem reading cache file $cache_filename (file_cache => 1) : $@")
    if $@;
  croak("HTML::Template::new() - Problem reading cache file $cache_filename (file_cache => 1) : $!") 
    unless defined $self->{record};

  ($self->{mtime}, 
   $self->{included_mtimes}, 
   $self->{param_map}, 
   $self->{parse_stack}) = @{$self->{record}};
  
  $options->{filepath} = $filepath;

  # validate the cache
  my $mtime = $self->_mtime($filepath);
  if (defined $mtime) {
    # return if the mtime doesn't match the cache
    if (defined($self->{mtime}) and 
        ($mtime != $self->{mtime})) {
      $options->{cache_debug} and 
        print STDERR "### HTML::Template Cache Debug ### FILE CACHE MISS : $filepath : $mtime\n";
      ($self->{mtime}, 
       $self->{included_mtimes}, 
       $self->{param_map}, 
       $self->{parse_stack}) = (undef, undef, undef, undef);
      return;
    }

    # if the template has includes, check each included file's mtime
    # and return if different
    if (exists($self->{included_mtimes})) {
      foreach my $filename (keys %{$self->{included_mtimes}}) {
        next unless 
          defined($self->{included_mtimes}{$filename});
        
        my $included_mtime = (stat($filename))[9];
        if ($included_mtime != $self->{included_mtimes}{$filename}) {
          $options->{cache_debug} and 
            print STDERR "### HTML::Template Cache Debug ### FILE CACHE MISS : $filepath : INCLUDE $filename : $included_mtime\n";
          ($self->{mtime}, 
           $self->{included_mtimes}, 
           $self->{param_map}, 
           $self->{parse_stack}) = (undef, undef, undef, undef);
          return;
        }
      }
    }
  }

  # got a cache hit!
  $options->{cache_debug} and print STDERR "### HTML::Template Cache Debug ### FILE CACHE HIT : $filepath\n";

  # clear out values from param_map from last run
  $self->_normalize_options();
  $self->clear_params();
}

sub _commit_to_file_cache {
  my $self = shift;
  my $options = $self->{options};

  my $filepath = $options->{filepath};
  if (not defined $filepath) {
    $filepath = $self->_find_file($options->{filename});
    confess("HTML::Template->new() : Cannot open included file $options->{filename} : file not found.")
      unless defined($filepath);
    $options->{filepath} = $filepath;   
  }

  my ($cache_dir, $cache_file) = $self->_get_cache_filename($filepath);  
  $cache_dir = File::Spec->join($options->{file_cache_dir}, $cache_dir);
  if (not -d $cache_dir) {
    if (not -d $options->{file_cache_dir}) {
      mkdir($options->{file_cache_dir},$options->{file_cache_dir_mode})
	or croak("HTML::Template->new() : can't mkdir $options->{file_cache_dir} (file_cache => 1): $!");
    }
    mkdir($cache_dir,$options->{file_cache_dir_mode})
      or croak("HTML::Template->new() : can't mkdir $cache_dir (file_cache => 1): $!");
  }

  $options->{cache_debug} and print STDERR "### HTML::Template Cache Debug ### FILE CACHE LOAD : $options->{filepath}\n";

  my $result;
  eval {
    $result = Storable::lock_store([ $self->{mtime},
                                     $self->{included_mtimes}, 
                                     $self->{param_map}, 
                                     $self->{parse_stack} ],
                                   scalar File::Spec->join($cache_dir, $cache_file)
                                  );
  };
  croak("HTML::Template::new() - Problem writing cache file $cache_dir/$cache_file (file_cache => 1) : $@")
    if $@;
  croak("HTML::Template::new() - Problem writing cache file $cache_dir/$cache_file (file_cache => 1) : $!")
    unless defined $result;
}

# Shared cache routines.
sub _fetch_from_shared_cache {
  my $self = shift;
  my $options = $self->{options};

  my $filepath = $self->_find_file($options->{filename});
  return unless defined $filepath;

  # fetch from the shared cache.
  $self->{record} = $self->{cache}{$filepath};
  
  ($self->{mtime}, 
   $self->{included_mtimes}, 
   $self->{param_map}, 
   $self->{parse_stack}) = @{$self->{record}}
     if defined($self->{record});
  
  $options->{cache_debug} and defined($self->{record}) and print STDERR "### HTML::Template Cache Debug ### CACHE HIT : $filepath\n";
  # clear out values from param_map from last run
  $self->_normalize_options(), $self->clear_params()
    if (defined($self->{record}));
  delete($self->{record});

  return $self;
}

sub _validate_shared_cache {
  my ($self, $filename, $record) = @_;
  my $options = $self->{options};

  $options->{shared_cache_debug} and print STDERR "### HTML::Template Cache Debug ### SHARED CACHE VALIDATE : $filename\n";

  return 1 if $options->{blind_cache};

  my ($c_mtime, $included_mtimes, $param_map, $parse_stack) = @$record;

  # if the modification time has changed return false
  my $mtime = $self->_mtime($filename);
  if (defined $mtime and defined $c_mtime
      and $mtime != $c_mtime) {
    $options->{cache_debug} and 
      print STDERR "### HTML::Template Cache Debug ### SHARED CACHE MISS : $filename : $mtime\n";
    return 0;
  }

  # if the template has includes, check each included file's mtime
  # and return false if different
  if (defined $mtime and defined $included_mtimes) {
    foreach my $fname (keys %$included_mtimes) {
      next unless defined($included_mtimes->{$fname});
      if ($included_mtimes->{$fname} != (stat($fname))[9]) {
        $options->{cache_debug} and 
          print STDERR "### HTML::Template Cache Debug ### SHARED CACHE MISS : $filename : INCLUDE $fname\n";
        return 0;
      }
    }
  }

  # all done - return true
  return 1;
}

sub _load_shared_cache {
  my ($self, $filename) = @_;
  my $options = $self->{options};
  my $cache = $self->{cache};
  
  $self->_init_template();
  $self->_parse();

  $options->{cache_debug} and print STDERR "### HTML::Template Cache Debug ### SHARED CACHE LOAD : $options->{filepath}\n";
  
  print STDERR "### HTML::Template Memory Debug ### END CACHE LOAD ", $self->{proc_mem}->size(), "\n"
    if $options->{memory_debug};

  return [ $self->{mtime},
           $self->{included_mtimes}, 
           $self->{param_map}, 
           $self->{parse_stack} ]; 
}

# utility function - given a filename performs documented search and
# returns a full path of undef if the file cannot be found.
sub _find_file {
  my ($self, $filename, $extra_path) = @_;
  my $options = $self->{options};
  my $filepath;

  # first check for a full path
  return File::Spec->canonpath($filename)
    if (File::Spec->file_name_is_absolute($filename) and (-e $filename));

  # try the extra_path if one was specified
  if (defined($extra_path)) {
    $extra_path->[$#{$extra_path}] = $filename;
    $filepath = File::Spec->canonpath(File::Spec->catfile(@$extra_path));
    return File::Spec->canonpath($filepath) if -e $filepath;
  }

  # try pre-prending HTML_Template_Root
  if (exists($ENV{HTML_TEMPLATE_ROOT})) {
    $filepath =  File::Spec->catfile($ENV{HTML_TEMPLATE_ROOT}, $filename);
    return File::Spec->canonpath($filepath) if -e $filepath;
  }

  # try "path" option list..
  foreach my $path (@{$options->{path}}) {
    $filepath = File::Spec->canonpath(File::Spec->catfile($path, $filename));
    return File::Spec->canonpath($filepath) if -e $filepath;
  }

  # try even a relative path from the current directory...
  return File::Spec->canonpath($filename) if -e $filename;
  
  return undef;
}

# utility function - computes the mtime for $filename
sub _mtime {
  my ($self, $filepath) = @_;
  my $options = $self->{options};
  
  return(undef) if ($options->{blind_cache});

  # make sure it still exists in the filesystem 
  (-r $filepath) or Carp::confess("HTML::Template : template file $filepath does not exist or is unreadable.");
  
  # get the modification time
  return (stat(_))[9];
}

# utility function - enforces new() options across LOOPs that have
# come from a cache.  Otherwise they would have stale options hashes.
sub _normalize_options {
  my $self = shift;
  my $options = $self->{options};

  my @pstacks = ($self->{parse_stack});
  while(@pstacks) {
    my $pstack = pop(@pstacks);
    foreach my $item (@$pstack) {
      next unless (ref($item) eq 'HTML::Template::LOOP');
      foreach my $template (values %{$item->[HTML::Template::LOOP::TEMPLATE_HASH]}) {
        # must be the same list as the call to _new_from_loop...
        $template->{options}{debug} = $options->{debug};
        $template->{options}{stack_debug} = $options->{stack_debug};
        $template->{options}{die_on_bad_params} = $options->{die_on_bad_params};
        $template->{options}{case_sensitive} = $options->{case_sensitive};