Improve Drupal's performance by not executing block logic on page templates with no regions - Part 2

This is a follow up of an earlier post. You should read this one to understand this one fully: Improve Drupal's performance by not executing block logic on page templates with no regions.

As I told there in the final paragraph, it was possible to generalize this technique to work on multiple templates with a different combination of blocks. This is a general solution to solve this.

As you know, you can have multiple page templates in PHPTemplate by settings $vars['template_file'] in theme_page. We add this variable in _phptemplate_variables for the 'page' hook.

function _phptemplate_variables($hook, $vars) {
  if ($hook == 'page') {
		$vars['template_file'] = phptemplate_get_template();
    return $vars;
  }
  return array();
}

Note that we moved the logic for deciding which page template we use in a seperate function, which implementation is here. This is the only function you need to adjust to your context. The other code you can just copy-paste and reuse in your own templates.

function phptemplate_get_template() {
	static $active_template;
	
	if(isset($active_template)) {
		return $active_template;
	}

	if(drupal_is_front_page()) {
		$active_template = 'page-left';
	} else {
		$active_template = 'page';
	}
	
	return $active_template;
}

We also define a mapping to specify what regions are used on what templates.

function phptemplate_get_template_regions($region) {
	$map = array(
		'page' => array('content', 'left', 'right'),
		'page-left' => array('content', 'left'),
	);
	return $map[$region];
}

As told in the previous article, the core logic of the block was executed on demand of the block_list function. This function was called from the theme_blocks function.

We don't want to run the block_list function on regions that don't appear in our page template, so we put a wrapper function around the core function.

function phptemplate_block_list($region) {
	if(!in_array($region, phptemplate_get_template_regions(phptemplate_get_template()))) {
		return array();
	}
	
	return block_list($region);
}

And now we override theme_blocks to call this function:

function phptemplate_blocks($region) {
  $output = '';

  if ($list = phptemplate_block_list($region)) {
    foreach ($list as $key => $block) {
      // $key == <i>module</i>_<i>delta</i>
      $output .= theme('block', $block);
    }
  }

  // Add any content assigned to this region through drupal_set_content() calls.
  $output .= drupal_get_content($region);

  return $output;
}

And we're done!

To apply this to your own themes, just copy all these functions and change my implementation of phptemplate_get_template and phptemplate_get_template_regions to your situation. If you already have your own _phptemplate_variables, add my logic to yours.