Fractal component loader plugin for Craft cms

FractalPlugin.php

<?php

namespace Craft;

class FractalPlugin extends BasePlugin
{

    public function init()
    {
        craft()->templates->getTwig()->setLoader(new FractalTemplateLoader());
    }

    public function getName()
    {
         return Craft::t('Fractal');
    }

    public function getVersion()
    {
        return '0.1.0';
    }

    public function getDeveloper()
    {
        return 'Clearleft';
    }

    public function getDeveloperUrl()
    {
        return 'http://clearleft.com';
    }

    public function hasCpSection()
    {
        return false;
    }

}

class FractalTemplateLoader implements \Twig_LoaderInterface
{
    // Public Methods
	// =========================================================================

	 /**
	 * Checks if a template exists.
	 *
	 * @param string $name
	  *
	 * @return bool
	 */
	public function exists($name)
	{
		return craft()->templates->doesTemplateExist($name);
	}

	/**
	 * Gets the source code of a template.
	 *
	 * @param  string $name The name of the template to load, or a StringTemplate object.
	 *
	 * @throws Exception
	 * @return string The template source code.
	 */
	public function getSource($name)
	{
		if (is_string($name))
		{
			$template = $this->_findTemplate($name);

			if (IOHelper::isReadable($template))
			{
				return IOHelper::getFileContents($template);
			}
			else
			{
				throw new Exception(Craft::t('Tried to read the template at {path}, but could not. Check the permissions.', array('path' => $template)));
			}
		}
		else
		{
			return $name->template;
		}
	}

	/**
	 * Gets the cache key to use for the cache for a given template.
	 *
	 * @param string $name The name of the template to load, or a StringTemplate object.
	 *
	 * @return string The cache key (the path to the template)
	 */
	public function getCacheKey($name)
	{
		if (is_string($name))
		{
			return $this->_findTemplate($name);
		}
		else
		{
			return $name->cacheKey;
		}
	}

	/**
	 * Returns whether the cached template is still up-to-date with the latest template.
	 *
	 * @param string $name The template name, or a StringTemplate object.
	 * @param int    $time The last modification time of the cached template
	 *
	 * @return bool
	 */
	public function isFresh($name, $time)
	{
		// If this is a CP request and a DB update is needed, force a recompile.
		if (craft()->request->isCpRequest() && craft()->updates->isCraftDbMigrationNeeded())
		{
			return false;
		}

		if (is_string($name))
		{
			$sourceModifiedTime = IOHelper::getLastTimeModified($this->_findTemplate($name));
			return $sourceModifiedTime && $sourceModifiedTime->getTimestamp() <= $time;
		}
		else
		{
			return false;
		}
	}

	// Private Methods
	// =========================================================================

	/**
	 * Returns the path to a given template, or throws a TemplateLoaderException.
	 *
	 * @param $name
	 *
	 * @throws TemplateLoaderException
	 * @return string $name
	 */

	private function _findTemplate($name)
	{
        if (strpos($name, '@') === 0)
        {
            $mappingPath = defined('FRACTAL_COMPONENTS_MAP') ? FRACTAL_COMPONENTS_MAP : CRAFT_BASE_PATH . '../components-map.json';
            if (IOHelper::isReadable($mappingPath))
            {
                $mappings = json_decode(IOHelper::getFileContents($mappingPath));
                if ($mappings->$name) {
                    if (strpos($mappings->$name, '/') !== 0) {
                        $template = realpath(CRAFT_BASE_PATH . '../') . '/' . $mappings->$name;
                    } else {
                        $template = $mappings->$name;
                    }
                }
            }
            else
            {
                throw new Exception(Craft::t('Could not read Fractal mappings file at %s.', array('path' => FRACTAL_COMPONENTS_MAP)));
            }
        }
        else
        {
            $template = craft()->templates->findTemplate($name);
        }

		if (!$template)
		{
			throw new TemplateLoaderException($name);
		}

		return $template;
	}
}

We have converted this into a Craft 3 plugin here - https://github.com/ournameismud/fractal