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<?php
/**
 * WP_Theme Class
 *
 * @package WordPress
 * @subpackage Theme
 * @since 3.4.0
 */
#[AllowDynamicProperties]
final class WP_Theme implements ArrayAccess {

	/**
	 * Whether the theme has been marked as updateable.
	 *
	 * @since 4.4.0
	 * @var bool
	 *
	 * @see WP_MS_Themes_List_Table
	 */
	public $update = false;

	/**
	 * Headers for style.css files.
	 *
	 * @since 3.4.0
	 * @since 5.4.0 Added `Requires at least` and `Requires PHP` headers.
	 * @since 6.1.0 Added `Update URI` header.
	 * @var string[]
	 */
	private static $file_headers = array(
		'Name'        => 'Theme Name',
		'ThemeURI'    => 'Theme URI',
		'Description' => 'Description',
		'Author'      => 'Author',
		'AuthorURI'   => 'Author URI',
		'Version'     => 'Version',
		'Template'    => 'Template',
		'Status'      => 'Status',
		'Tags'        => 'Tags',
		'TextDomain'  => 'Text Domain',
		'DomainPath'  => 'Domain Path',
		'RequiresWP'  => 'Requires at least',
		'RequiresPHP' => 'Requires PHP',
		'UpdateURI'   => 'Update URI',
	);

	/**
	 * Default themes.
	 *
	 * @since 3.4.0
	 * @since 3.5.0 Added the Twenty Twelve theme.
	 * @since 3.6.0 Added the Twenty Thirteen theme.
	 * @since 3.8.0 Added the Twenty Fourteen theme.
	 * @since 4.1.0 Added the Twenty Fifteen theme.
	 * @since 4.4.0 Added the Twenty Sixteen theme.
	 * @since 4.7.0 Added the Twenty Seventeen theme.
	 * @since 5.0.0 Added the Twenty Nineteen theme.
	 * @since 5.3.0 Added the Twenty Twenty theme.
	 * @since 5.6.0 Added the Twenty Twenty-One theme.
	 * @since 5.9.0 Added the Twenty Twenty-Two theme.
	 * @since 6.1.0 Added the Twenty Twenty-Three theme.
	 * @since 6.4.0 Added the Twenty Twenty-Four theme.
	 * @since 6.7.0 Added the Twenty Twenty-Five theme.
	 * @var string[]
	 */
	private static $default_themes = array(
		'classic'           => 'WordPress Classic',
		'default'           => 'WordPress Default',
		'twentyten'         => 'Twenty Ten',
		'twentyeleven'      => 'Twenty Eleven',
		'twentytwelve'      => 'Twenty Twelve',
		'twentythirteen'    => 'Twenty Thirteen',
		'twentyfourteen'    => 'Twenty Fourteen',
		'twentyfifteen'     => 'Twenty Fifteen',
		'twentysixteen'     => 'Twenty Sixteen',
		'twentyseventeen'   => 'Twenty Seventeen',
		'twentynineteen'    => 'Twenty Nineteen',
		'twentytwenty'      => 'Twenty Twenty',
		'twentytwentyone'   => 'Twenty Twenty-One',
		'twentytwentytwo'   => 'Twenty Twenty-Two',
		'twentytwentythree' => 'Twenty Twenty-Three',
		'twentytwentyfour'  => 'Twenty Twenty-Four',
		'twentytwentyfive'  => 'Twenty Twenty-Five',
	);

	/**
	 * Renamed theme tags.
	 *
	 * @since 3.8.0
	 * @var string[]
	 */
	private static $tag_map = array(
		'fixed-width'    => 'fixed-layout',
		'flexible-width' => 'fluid-layout',
	);

	/**
	 * Absolute path to the theme root, usually wp-content/themes
	 *
	 * @since 3.4.0
	 * @var string
	 */
	private $theme_root;

	/**
	 * Header data from the theme's style.css file.
	 *
	 * @since 3.4.0
	 * @var array
	 */
	private $headers = array();

	/**
	 * Header data from the theme's style.css file after being sanitized.
	 *
	 * @since 3.4.0
	 * @var array
	 */
	private $headers_sanitized;

	/**
	 * Is this theme a block theme.
	 *
	 * @since 6.2.0
	 * @var bool
	 */
	private $block_theme;

	/**
	 * Header name from the theme's style.css after being translated.
	 *
	 * Cached due to sorting functions running over the translated name.
	 *
	 * @since 3.4.0
	 * @var string
	 */
	private $name_translated;

	/**
	 * Errors encountered when initializing the theme.
	 *
	 * @since 3.4.0
	 * @var WP_Error
	 */
	private $errors;

	/**
	 * The directory name of the theme's files, inside the theme root.
	 *
	 * In the case of a child theme, this is directory name of the child theme.
	 * Otherwise, 'stylesheet' is the same as 'template'.
	 *
	 * @since 3.4.0
	 * @var string
	 */
	private $stylesheet;

	/**
	 * The directory name of the theme's files, inside the theme root.
	 *
	 * In the case of a child theme, this is the directory name of the parent theme.
	 * Otherwise, 'template' is the same as 'stylesheet'.
	 *
	 * @since 3.4.0
	 * @var string
	 */
	private $template;

	/**
	 * A reference to the parent theme, in the case of a child theme.
	 *
	 * @since 3.4.0
	 * @var WP_Theme
	 */
	private $parent;

	/**
	 * URL to the theme root, usually an absolute URL to wp-content/themes
	 *
	 * @since 3.4.0
	 * @var string
	 */
	private $theme_root_uri;

	/**
	 * Flag for whether the theme's textdomain is loaded.
	 *
	 * @since 3.4.0
	 * @var bool
	 */
	private $textdomain_loaded;

	/**
	 * Stores an md5 hash of the theme root, to function as the cache key.
	 *
	 * @since 3.4.0
	 * @var string
	 */
	private $cache_hash;

	/**
	 * Block template folders.
	 *
	 * @since 6.4.0
	 * @var string[]
	 */
	private $block_template_folders;

	/**
	 * Default values for template folders.
	 *
	 * @since 6.4.0
	 * @var string[]
	 */
	private $default_template_folders = array(
		'wp_template'      => 'templates',
		'wp_template_part' => 'parts',
	);

	/**
	 * Flag for whether the themes cache bucket should be persistently cached.
	 *
	 * Default is false. Can be set with the {@see 'wp_cache_themes_persistently'} filter.
	 *
	 * @since 3.4.0
	 * @var bool
	 */
	private static $persistently_cache;

	/**
	 * Expiration time for the themes cache bucket.
	 *
	 * By default the bucket is not cached, so this value is useless.
	 *
	 * @since 3.4.0
	 * @var bool
	 */
	private static $cache_expiration = 1800;

	/**
	 * Constructor for WP_Theme.
	 *
	 * @since 3.4.0
	 *
	 * @global array $wp_theme_directories
	 *
	 * @param string        $theme_dir  Directory of the theme within the theme_root.
	 * @param string        $theme_root Theme root.
	 * @param WP_Theme|null $_child If this theme is a parent theme, the child may be passed for validation purposes.
	 */
	public function __construct( $theme_dir, $theme_root, $_child = null ) {
		global $wp_theme_directories;

		// Initialize caching on first run.
		if ( ! isset( self::$persistently_cache ) ) {
			/** This action is documented in wp-includes/theme.php */
			self::$persistently_cache = apply_filters( 'wp_cache_themes_persistently', false, 'WP_Theme' );
			if ( self::$persistently_cache ) {
				wp_cache_add_global_groups( 'themes' );
				if ( is_int( self::$persistently_cache ) ) {
					self::$cache_expiration = self::$persistently_cache;
				}
			} else {
				wp_cache_add_non_persistent_groups( 'themes' );
			}
		}

		// Handle a numeric theme directory as a string.
		$theme_dir = (string) $theme_dir;

		$this->theme_root = $theme_root;
		$this->stylesheet = $theme_dir;

		// Correct a situation where the theme is 'some-directory/some-theme' but 'some-directory' was passed in as part of the theme root instead.
		if ( ! in_array( $theme_root, (array) $wp_theme_directories, true )
			&& in_array( dirname( $theme_root ), (array) $wp_theme_directories, true )
		) {
			$this->stylesheet = basename( $this->theme_root ) . '/' . $this->stylesheet;
			$this->theme_root = dirname( $theme_root );
		}

		$this->cache_hash = md5( $this->theme_root . '/' . $this->stylesheet );
		$theme_file       = $this->stylesheet . '/style.css';

		$cache = $this->cache_get( 'theme' );

		if ( is_array( $cache ) ) {
			foreach ( array( 'block_template_folders', 'block_theme', 'errors', 'headers', 'template' ) as $key ) {
				if ( isset( $cache[ $key ] ) ) {
					$this->$key = $cache[ $key ];
				}
			}
			if ( $this->errors ) {
				return;
			}
			if ( isset( $cache['theme_root_template'] ) ) {
				$theme_root_template = $cache['theme_root_template'];
			}
		} elseif ( ! file_exists( $this->theme_root . '/' . $theme_file ) ) {
			$this->headers['Name'] = $this->stylesheet;
			if ( ! file_exists( $this->theme_root . '/' . $this->stylesheet ) ) {
				$this->errors = new WP_Error(
					'theme_not_found',
					sprintf(
						/* translators: %s: Theme directory name. */
						__( 'The theme directory "%s" does not exist.' ),
						esc_html( $this->stylesheet )
					)
				);
			} else {
				$this->errors = new WP_Error( 'theme_no_stylesheet', __( 'Stylesheet is missing.' ) );
			}
			$this->template               = $this->stylesheet;
			$this->block_theme            = false;
			$this->block_template_folders = $this->default_template_folders;
			$this->cache_add(
				'theme',
				array(
					'block_template_folders' => $this->block_template_folders,
					'block_theme'            => $this->block_theme,
					'headers'                => $this->headers,
					'errors'                 => $this->errors,
					'stylesheet'             => $this->stylesheet,
					'template'               => $this->template,
				)
			);
			if ( ! file_exists( $this->theme_root ) ) { // Don't cache this one.
				$this->errors->add( 'theme_root_missing', __( '<strong>Error:</strong> The themes directory is either empty or does not exist. Please check your installation.' ) );
			}
			return;
		} elseif ( ! is_readable( $this->theme_root . '/' . $theme_file ) ) {
			$this->headers['Name']        = $this->stylesheet;
			$this->errors                 = new WP_Error( 'theme_stylesheet_not_readable', __( 'Stylesheet is not readable.' ) );
			$this->template               = $this->stylesheet;
			$this->block_theme            = false;
			$this->block_template_folders = $this->default_template_folders;
			$this->cache_add(
				'theme',
				array(
					'block_template_folders' => $this->block_template_folders,
					'block_theme'            => $this->block_theme,
					'headers'                => $this->headers,
					'errors'                 => $this->errors,
					'stylesheet'             => $this->stylesheet,
					'template'               => $this->template,
				)
			);
			return;
		} else {
			$this->headers = get_file_data( $this->theme_root . '/' . $theme_file, self::$file_headers, 'theme' );
			/*
			 * Default themes always trump their pretenders.
			 * Properly identify default themes that are inside a directory within wp-content/themes.
			 */
			$default_theme_slug = array_search( $this->headers['Name'], self::$default_themes, true );
			if ( $default_theme_slug ) {
				if ( basename( $this->stylesheet ) !== $default_theme_slug ) {
					$this->headers['Name'] .= '/' . $this->stylesheet;
				}
			}
		}

		if ( ! $this->template && $this->stylesheet === $this->headers['Template'] ) {
			$this->errors = new WP_Error(
				'theme_child_invalid',
				sprintf(
					/* translators: %s: Template. */
					__( 'The theme defines itself as its parent theme. Please check the %s header.' ),
					'<code>Template</code>'
				)
			);
			$this->cache_add(
				'theme',
				array(
					'block_template_folders' => $this->get_block_template_folders(),
					'block_theme'            => $this->is_block_theme(),
					'headers'                => $this->headers,
					'errors'                 => $this->errors,
					'stylesheet'             => $this->stylesheet,
				)
			);

			return;
		}

		// (If template is set from cache [and there are no errors], we know it's good.)
		if ( ! $this->template ) {
			$this->template = $this->headers['Template'];
		}

		if ( ! $this->template ) {
			$this->template = $this->stylesheet;
			$theme_path     = $this->theme_root . '/' . $this->stylesheet;

			if ( ! $this->is_block_theme() && ! file_exists( $theme_path . '/index.php' ) ) {
				$error_message = sprintf(
					/* translators: 1: templates/index.html, 2: index.php, 3: Documentation URL, 4: Template, 5: style.css */
					__( 'Template is missing. Standalone themes need to have a %1$s or %2$s template file. <a href="%3$s">Child themes</a> need to have a %4$s header in the %5$s stylesheet.' ),
					'<code>templates/index.html</code>',
					'<code>index.php</code>',
					__( 'https://developer.wordpress.org/themes/advanced-topics/child-themes/' ),
					'<code>Template</code>',
					'<code>style.css</code>'
				);
				$this->errors = new WP_Error( 'theme_no_index', $error_message );
				$this->cache_add(
					'theme',
					array(
						'block_template_folders' => $this->get_block_template_folders(),
						'block_theme'            => $this->block_theme,
						'headers'                => $this->headers,
						'errors'                 => $this->errors,
						'stylesheet'             => $this->stylesheet,
						'template'               => $this->template,
					)
				);
				return;
			}
		}

		// If we got our data from cache, we can assume that 'template' is pointing to the right place.
		if ( ! is_array( $cache )
			&& $this->template !== $this->stylesheet
			&& ! file_exists( $this->theme_root . '/' . $this->template . '/index.php' )
		) {
			/*
			 * If we're in a directory of themes inside /themes, look for the parent nearby.
			 * wp-content/themes/directory-of-themes/*
			 */
			$parent_dir  = dirname( $this->stylesheet );
			$directories = search_theme_directories();

			if ( '.' !== $parent_dir
				&& file_exists( $this->theme_root . '/' . $parent_dir . '/' . $this->template . '/index.php' )
			) {
				$this->template = $parent_dir . '/' . $this->template;
			} elseif ( $directories && isset( $directories[ $this->template ] ) ) {
				/*
				 * Look for the template in the search_theme_directories() results, in case it is in another theme root.
				 * We don't look into directories of themes, just the theme root.
				 */
				$theme_root_template = $directories[ $this->template ]['theme_root'];
			} else {
				// Parent theme is missing.
				$this->errors = new WP_Error(
					'theme_no_parent',
					sprintf(
						/* translators: %s: Theme directory name. */
						__( 'The parent theme is missing. Please install the "%s" parent theme.' ),
						esc_html( $this->template )
					)
				);
				$this->cache_add(
					'theme',
					array(
						'block_template_folders' => $this->get_block_template_folders(),
						'block_theme'            => $this->is_block_theme(),
						'headers'                => $this->headers,
						'errors'                 => $this->errors,
						'stylesheet'             => $this->stylesheet,
						'template'               => $this->template,
					)
				);
				$this->parent = new WP_Theme( $this->template, $this->theme_root, $this );
				return;
			}
		}

		// Set the parent, if we're a child theme.
		if ( $this->template !== $this->stylesheet ) {
			// If we are a parent, then there is a problem. Only two generations allowed! Cancel things out.
			if ( $_child instanceof WP_Theme && $_child->template === $this->stylesheet ) {
				$_child->parent = null;
				$_child->errors = new WP_Error(
					'theme_parent_invalid',
					sprintf(
						/* translators: %s: Theme directory name. */
						__( 'The "%s" theme is not a valid parent theme.' ),
						esc_html( $_child->template )
					)
				);
				$_child->cache_add(
					'theme',
					array(
						'block_template_folders' => $_child->get_block_template_folders(),
						'block_theme'            => $_child->is_block_theme(),
						'headers'                => $_child->headers,
						'errors'                 => $_child->errors,
						'stylesheet'             => $_child->stylesheet,
						'template'               => $_child->template,
					)
				);
				// The two themes actually reference each other with the Template header.
				if ( $_child->stylesheet === $this->template ) {
					$this->errors = new WP_Error(
						'theme_parent_invalid',
						sprintf(
							/* translators: %s: Theme directory name. */
							__( 'The "%s" theme is not a valid parent theme.' ),
							esc_html( $this->template )
						)
					);
					$this->cache_add(
						'theme',
						array(
							'block_template_folders' => $this->get_block_template_folders(),
							'block_theme'            => $this->is_block_theme(),
							'headers'                => $this->headers,
							'errors'                 => $this->errors,
							'stylesheet'             => $this->stylesheet,
							'template'               => $this->template,
						)
					);
				}
				return;
			}
			// Set the parent. Pass the current instance so we can do the checks above and assess errors.
			$this->parent = new WP_Theme( $this->template, isset( $theme_root_template ) ? $theme_root_template : $this->theme_root, $this );
		}

		if ( wp_paused_themes()->get( $this->stylesheet ) && ( ! is_wp_error( $this->errors ) || ! isset( $this->errors->errors['theme_paused'] ) ) ) {
			$this->errors = new WP_Error( 'theme_paused', __( 'This theme failed to load properly and was paused within the admin backend.' ) );
		}

		// We're good. If we didn't retrieve from cache, set it.
		if ( ! is_array( $cache ) ) {
			$cache = array(
				'block_theme'            => $this->is_block_theme(),
				'block_template_folders' => $this->get_block_template_folders(),
				'headers'                => $this->headers,
				'errors'                 => $this->errors,
				'stylesheet'             => $this->stylesheet,
				'template'               => $this->template,
			);
			// If the parent theme is in another root, we'll want to cache this. Avoids an entire branch of filesystem calls above.
			if ( isset( $theme_root_template ) ) {
				$cache['theme_root_template'] = $theme_root_template;
			}
			$this->cache_add( 'theme', $cache );
		}
	}

	/**
	 * When converting the object to a string, the theme name is returned.
	 *
	 * @since 3.4.0
	 *
	 * @return string Theme name, ready for display (translated)
	 */
	public function __toString() {
		return (string) $this->display( 'Name' );
	}

	/**
	 * __isset() magic method for properties formerly returned by current_theme_info()
	 *
	 * @since 3.4.0
	 *
	 * @param string $offset Property to check if set.
	 * @return bool Whether the given property is set.
	 */
	public function __isset( $offset ) {
		static $properties = array(
			'name',
			'title',
			'version',
			'parent_theme',
			'template_dir',
			'stylesheet_dir',
			'template',
			'stylesheet',
			'screenshot',
			'description',
			'author',
			'tags',
			'theme_root',
			'theme_root_uri',
		);

		return in_array( $offset, $properties, true );
	}

	/**
	 * __get() magic method for properties formerly returned by current_theme_info()
	 *
	 * @since 3.4.0
	 *
	 * @param string $offset Property to get.
	 * @return mixed Property value.
	 */
	public function __get( $offset ) {
		switch ( $offset ) {
			case 'name':
			case 'title':
				return $this->get( 'Name' );
			case 'version':
				return $this->get( 'Version' );
			case 'parent_theme':
				return $this->parent() ? $this->parent()->get( 'Name' ) : '';
			case 'template_dir':
				return $this->get_template_directory();
			case 'stylesheet_dir':
				return $this->get_stylesheet_directory();
			case 'template':
				return $this->get_template();
			case 'stylesheet':
				return $this->get_stylesheet();
			case 'screenshot':
				return $this->get_screenshot( 'relative' );
			// 'author' and 'description' did not previously return translated data.
			case 'description':
				return $this->display( 'Description' );
			case 'author':
				return $this->display( 'Author' );
			case 'tags':
				return $this->get( 'Tags' );
			case 'theme_root':
				return $this->get_theme_root();
			case 'theme_root_uri':
				return $this->get_theme_root_uri();
			// For cases where the array was converted to an object.
			default:
				return $this->offsetGet( $offset );
		}
	}

	/**
	 * Method to implement ArrayAccess for keys formerly returned by get_themes()
	 *
	 * @since 3.4.0
	 *
	 * @param mixed $offset
	 * @param mixed $value
	 */
	#[ReturnTypeWillChange]
	public function offsetSet( $offset, $value ) {}

	/**
	 * Method to implement ArrayAccess for keys formerly returned by get_themes()
	 *
	 * @since 3.4.0
	 *
	 * @param mixed $offset
	 */
	#[ReturnTypeWillChange]
	public function offsetUnset( $offset ) {}

	/**
	 * Method to implement ArrayAccess for keys formerly returned by get_themes()
	 *
	 * @since 3.4.0
	 *
	 * @param mixed $offset
	 * @return bool
	 */
	#[ReturnTypeWillChange]
	public function offsetExists( $offset ) {
		static $keys = array(
			'Name',
			'Version',
			'Status',
			'Title',
			'Author',
			'Author Name',
			'Author URI',
			'Description',
			'Template',
			'Stylesheet',
			'Template Files',
			'Stylesheet Files',
			'Template Dir',
			'Stylesheet Dir',
			'Screenshot',
			'Tags',
			'Theme Root',
			'Theme Root URI',
			'Parent Theme',
		);

		return in_array( $offset, $keys, true );
	}

	/**
	 * Method to implement ArrayAccess for keys formerly returned by get_themes().
	 *
	 * Author, Author Name, Author URI, and Description did not previously return
	 * translated data. We are doing so now as it is safe to do. However, as
	 * Name and Title could have been used as the key for get_themes(), both remain
	 * untranslated for back compatibility. This means that ['Name'] is not ideal,
	 * and care should be taken to use `$theme::display( 'Name' )` to get a properly
	 * translated header.
	 *
	 * @since 3.4.0
	 *
	 * @param mixed $offset
	 * @return mixed
	 */
	#[ReturnTypeWillChange]
	public function offsetGet( $offset ) {
		switch ( $offset ) {
			case 'Name':
			case 'Title':
				/*
				 * See note above about using translated data. get() is not ideal.
				 * It is only for backward compatibility. Use display().
				 */
				return $this->get( 'Name' );
			case 'Author':
				return $this->display( 'Author' );
			case 'Author Name':
				return $this->display( 'Author', false );
			case 'Author URI':
				return $this->display( 'AuthorURI' );
			case 'Description':
				return $this->display( 'Description' );
			case 'Version':
			case 'Status':
				return $this->get( $offset );
			case 'Template':
				return $this->get_template();
			case 'Stylesheet':
				return $this->get_stylesheet();
			case 'Template Files':
				return $this->get_files( 'php', 1, true );
			case 'Stylesheet Files':
				return $this->get_files( 'css', 0, false );
			case 'Template Dir':
				return $this->get_template_directory();
			case 'Stylesheet Dir':
				return $this->get_stylesheet_directory();
			case 'Screenshot':
				return $this->get_screenshot( 'relative' );
			case 'Tags':
				return $this->get( 'Tags' );
			case 'Theme Root':
				return $this->get_theme_root();
			case 'Theme Root URI':
				return $this->get_theme_root_uri();
			case 'Parent Theme':
				return $this->parent() ? $this->parent()->get( 'Name' ) : '';
			default:
				return null;
		}
	}

	/**
	 * Returns errors property.
	 *
	 * @since 3.4.0
	 *
	 * @return WP_Error|false WP_Error if there are errors, or false.
	 */
	public function errors() {
		return is_wp_error( $this->errors ) ? $this->errors : false;
	}

	/**
	 * Determines whether the theme exists.
	 *
	 * A theme with errors exists. A theme with the error of 'theme_not_found',
	 * meaning that the theme's directory was not found, does not exist.
	 *
	 * @since 3.4.0
	 *
	 * @return bool Whether the theme exists.
	 */
	public function exists() {
		return ! ( $this->errors() && in_array( 'theme_not_found', $this->errors()->get_error_codes(), true ) );
	}

	/**
	 * Returns reference to the parent theme.
	 *
	 * @since 3.4.0
	 *
	 * @return WP_Theme|false Parent theme, or false if the active theme is not a child theme.
	 */
	public function parent() {
		return isset( $this->parent ) ? $this->parent : false;
	}

	/**
	 * Perform reinitialization tasks.
	 *
	 * Prevents a callback from being injected during unserialization of an object.
	 */
	public function __wakeup() {
		if ( $this->parent && ! $this->parent instanceof self ) {
			throw new UnexpectedValueException();
		}
		if ( $this->headers && ! is_array( $this->headers ) ) {
			throw new UnexpectedValueException();
		}
		foreach ( $this->headers as $value ) {
			if ( ! is_string( $value ) ) {
				throw new UnexpectedValueException();
			}
		}
		$this->headers_sanitized = array();
	}

	/**
	 * Adds theme data to cache.
	 *
	 * Cache entries keyed by the theme and the type of data.
	 *
	 * @since 3.4.0
	 *
	 * @param string       $key  Type of data to store (theme, screenshot, headers, post_templates)
	 * @param array|string $data Data to store
	 * @return bool Return value from wp_cache_add()
	 */
	private function cache_add( $key, $data ) {
		return wp_cache_add( $key . '-' . $this->cache_hash, $data, 'themes', self::$cache_expiration );
	}

	/**
	 * Gets theme data from cache.
	 *
	 * Cache entries are keyed by the theme and the type of data.
	 *
	 * @since 3.4.0
	 *
	 * @param string $key Type of data to retrieve (theme, screenshot, headers, post_templates)
	 * @return mixed Retrieved data
	 */
	private function cache_get( $key ) {
		return wp_cache_get( $key . '-' . $this->cache_hash, 'themes' );
	}

	/**
	 * Clears the cache