RulePool.php

<?php
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */

namespace Magento\Framework\View\Design\Fallback;

use Magento\Framework\App\Filesystem\DirectoryList;
use Magento\Framework\View\Design\Fallback\Rule\Composite;
use Magento\Framework\View\Design\Fallback\Rule\RuleInterface;

/**
 * Fallback Factory
 *
 * Factory that produces all sorts of fallback rules
 */
class RulePool
{
    /**#@+
     * Supported types of fallback rules
     */
    const TYPE_FILE = 'file';
    const TYPE_LOCALE_FILE = 'locale';
    const TYPE_TEMPLATE_FILE = 'template';
    const TYPE_STATIC_FILE = 'static';
    const TYPE_EMAIL_TEMPLATE = 'email';
    /**#@-*/

    /**#@-*/
    protected $filesystem;

    /**
     * Rules
     *
     * @var array
     */
    private $rules = [];

    /**
     * Factory for simple rule
     *
     * @var \Magento\Framework\View\Design\Fallback\Rule\SimpleFactory
     */
    private $simpleFactory;

    /**
     * Factory for theme rule
     *
     * @var Rule\ThemeFactory
     */
    private $themeFactory;

    /**
     * Factory for modular switcher
     *
     * @var Rule\ModularSwitchFactory
     */
    private $modularSwitchFactory;

    /**
     * Factory for module rule
     *
     * @var Rule\ModuleFactory
     */
    private $moduleFactory;

    /**
     * Constructor
     *
     * @param \Magento\Framework\Filesystem $filesystem
     * @param Rule\SimpleFactory $simpleFactory
     * @param Rule\ThemeFactory $themeFactory
     * @param Rule\ModuleFactory $moduleFactory
     * @param Rule\ModularSwitchFactory $modularSwitchFactory
     */
    public function __construct(
        \Magento\Framework\Filesystem $filesystem,
        Rule\SimpleFactory $simpleFactory,
        Rule\ThemeFactory $themeFactory,
        Rule\ModuleFactory $moduleFactory,
        Rule\ModularSwitchFactory $modularSwitchFactory
    ) {
        $this->filesystem = $filesystem;
        $this->simpleFactory = $simpleFactory;
        $this->themeFactory = $themeFactory;
        $this->moduleFactory = $moduleFactory;
        $this->modularSwitchFactory = $modularSwitchFactory;
    }

    /**
     * Retrieve newly created fallback rule for locale files, such as CSV translation maps
     *
     * @return RuleInterface
     */
    protected function createLocaleFileRule()
    {
        return $this->themeFactory->create(
            ['rule' => $this->simpleFactory->create(['pattern' => "<theme_dir>"])]
        );
    }

    /**
     * Retrieve newly created fallback rule for template files
     *
     * @return RuleInterface
     */
    protected function createTemplateFileRule()
    {
        return $this->modularSwitchFactory->create(
            ['ruleNonModular' =>
            $this->themeFactory->create(
                ['rule' => $this->simpleFactory->create(['pattern' => "<theme_dir>/templates"])]
            ),
            'ruleModular' => new Composite(
                [
                    $this->themeFactory->create(
                        ['rule' => $this->simpleFactory->create(['pattern' => "<theme_dir>/<module_name>/templates"])]
                    ),
                    $this->moduleFactory->create(
                        ['rule' => $this->simpleFactory->create(['pattern' => "<module_dir>/view/<area>/templates"])]
                    ),
                    $this->moduleFactory->create(
                        ['rule' => $this->simpleFactory->create(['pattern' => "<module_dir>/view/base/templates"])]
                    ),
                ]
            )]
        );
    }

    /**
     * Retrieve newly created fallback rule for dynamic view files
     *
     * @return RuleInterface
     */
    protected function createFileRule()
    {
        return $this->modularSwitchFactory->create(
            ['ruleNonModular' => $this->themeFactory->create(
                ['rule' => $this->simpleFactory->create(['pattern' => "<theme_dir>"])]
            ),
            'ruleModular' => new Composite(
                [
                    $this->themeFactory->create(
                        ['rule' => $this->simpleFactory->create(['pattern' => "<theme_dir>/<module_name>"])]
                    ),
                    $this->moduleFactory->create(
                        ['rule' => $this->simpleFactory->create(['pattern' => "<module_dir>/view/<area>"])]
                    ),
                    $this->moduleFactory->create(
                        ['rule' => $this->simpleFactory->create(['pattern' => "<module_dir>/view/base"])]
                    ),
                ]
            )]
        );
    }

    /**
     * Retrieve newly created fallback rule for static view files, such as CSS, JavaScript, images, etc.
     *
     * @return RuleInterface
     */
    protected function createViewFileRule()
    {
        $libDir = rtrim($this->filesystem->getDirectoryRead(DirectoryList::LIB_WEB)->getAbsolutePath(), '/');
        return $this->modularSwitchFactory->create(
            ['ruleNonModular' => new Composite(
                [
                    $this->themeFactory->create(
                        ['rule' =>
                        new Composite(
                            [
                                $this->simpleFactory
                                    ->create([
                                        'pattern' => "<theme_dir>/web/i18n/<locale>",
                                        'optionalParams' => ['locale']
                                    ]),
                                $this->simpleFactory
                                    ->create(['pattern' => "<theme_dir>/web"]),
                                $this->simpleFactory
                                    ->create([
                                        'pattern' => "<theme_pubstatic_dir>",
                                        'optionalParams' => ['theme_pubstatic_dir']
                                    ]),
                            ]
                        )]
                    ),
                    $this->simpleFactory->create(['pattern' => $libDir]),
                ]
            ),
            'ruleModular' => new Composite(
                [
                    $this->themeFactory->create(
                        ['rule' =>
                        new Composite(
                            [
                                $this->simpleFactory->create(
                                    [
                                        'pattern' => "<theme_dir>/<module_name>/web/i18n/<locale>",
                                        'optionalParams' => ['locale'],
                                    ]
                                ),
                                $this->simpleFactory->create(
                                    ['pattern' => "<theme_dir>/<module_name>/web"]
                                ),
                            ]
                        )]
                    ),
                    $this->moduleFactory->create(
                        ['rule' => $this->simpleFactory->create(
                            [
                                'pattern' => "<module_dir>/view/<area>/web/i18n/<locale>",
                                'optionalParams' => ['locale']
                            ]
                        )]
                    ),
                    $this->moduleFactory->create(
                        ['rule' => $this->simpleFactory->create(
                            [
                                'pattern' => "<module_dir>/view/base/web/i18n/<locale>",
                                'optionalParams' => ['locale']
                            ]
                        )]
                    ),
                    $this->moduleFactory->create(
                        ['rule' => $this->simpleFactory->create(['pattern' => "<module_dir>/view/<area>/web"])]
                    ),
                    $this->moduleFactory->create(
                        ['rule' => $this->simpleFactory->create(['pattern' => "<module_dir>/view/base/web"])]
                    ),
                ]
            )]
        );
    }

    /**
     * Retrieve newly created fallback rule for email templates.
     *
     * Emails are only loaded in a modular context, so a non-modular rule is not specified.
     *
     * @return RuleInterface
     */
    protected function createEmailTemplateFileRule()
    {
        return new Composite(
            [
                $this->themeFactory->create(
                    ['rule' =>
                    $this->simpleFactory->create(
                        ['pattern' => "<theme_dir>/<module_name>/email"]
                    )]
                ),
                $this->moduleFactory->create(
                    ['rule' => $this->simpleFactory->create(['pattern' => "<module_dir>/view/<area>/email"])]
                ),
            ]
        );
    }

    /**
     * Get rule by type
     *
     * @param string $type
     * @return RuleInterface
     * @throws \InvalidArgumentException
     */
    public function getRule($type)
    {
        if (isset($this->rules[$type])) {
            return $this->rules[$type];
        }
        switch ($type) {
            case self::TYPE_FILE:
                $rule = $this->createFileRule();
                break;
            case self::TYPE_LOCALE_FILE:
                $rule = $this->createLocaleFileRule();
                break;
            case self::TYPE_TEMPLATE_FILE:
                $rule = $this->createTemplateFileRule();
                break;
            case self::TYPE_STATIC_FILE:
                $rule = $this->createViewFileRule();
                break;
            case self::TYPE_EMAIL_TEMPLATE:
                $rule = $this->createEmailTemplateFileRule();
                break;
            default:
                throw new \InvalidArgumentException("Fallback rule '$type' is not supported");
        }
        $this->rules[$type] = $rule;
        return $this->rules[$type];
    }
}