WP_Theme::__construct( string $theme_dir, string $theme_root, WP_Theme|null $_child = null )

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$theme_dirstring

Directory of the theme within the theme_root.

$theme_rootstring

Theme root.

$_childWP_Theme|nulloptional

If this theme is a parent theme, the child may be passed for validation purposes.Default: null

Performance profile

How much work a call to WP_Theme::__construct() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Heavy

Reads or writes the filesystem via file_exists().

Scaling

Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions

92–206

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 601.

Plugin surface

1 hook

Third-party callbacks on 'wp_cache_themes_persistently' run inside this call, and their cost is not bounded by anything here.

Called by

5

5 places in core call this, so the cost is paid more often than your own code shows.

What it touches

• hookthird-party callbacksapply_filters()called directly
• cacheobject cachewp_cache_add_global_groups()called directly
• filesystemfilesystem accessfile_exists()called directly
• transienttransientget_site_transient()one call below WP_Theme::__construct()

Further down the call graph this can also reach option, serialize and query. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 72 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost WP_Theme::__construct() can have, taken from its control-flow graph on PHP 8.5.

This body has more branch combinations than are worth enumerating, so the table covers the outcomes found first rather than every one that exists.

Hooks and filters fired · 1

One hook fires while WP_Theme::__construct() runs, in this order:

1. 1
   apply_filters( wp_cache_themes_persistently )filterline 257 (+6 into the body)

   Filters whether to get the cache of the registered theme directories.

Uses · 16

• apply_filters()Calls the callback functions that have been added to a filter hook.
• wp_cache_add_global_groups()Adds a group or set of groups to the list of global groups.
• wp_cache_add_non_persistent_groups()Adds a group or set of groups to the list of non-persistent groups.
• __()Retrieves the translation of $text.
• esc_html()Escaping for HTML blocks.
• get_file_data()Retrieves metadata from a file.
• search_theme_directories()Searches all registered theme directories for complete and valid themes.
• wp_paused_themes()Get the instance for storing paused extensions.
• is_wp_error()Checks whether the given variable is a WordPress Error.
• WP_Theme::cache_get()Gets theme data from cache.
• WP_Error::__construct()Initializes the error.
• WP_Theme::cache_add()Adds theme data to cache.

Used by · 5

• WP_Theme::__construct()Constructor for WP_Theme.
• WP_Theme::cache_delete()Clears the cache for the theme.
• get_theme_data()Retrieve theme data from parsed theme file.
• wp_get_theme()Gets a WP_Theme object for a theme.
• wp_get_themes()Returns an array of WP_Theme objects based on the arguments.

Source code

View on Trac ↗View on GitHub ↗

251	public function __construct( $theme_dir, $theme_root, $_child = null ) {252		global $wp_theme_directories;253 254		// Initialize caching on first run.255		if ( ! isset( self::$persistently_cache ) ) {256			/** This action is documented in wp-includes/theme.php */257			self::$persistently_cache = apply_filters( 'wp_cache_themes_persistently', false, 'WP_Theme' );258			if ( self::$persistently_cache ) {259				wp_cache_add_global_groups( 'themes' );260				if ( is_int( self::$persistently_cache ) ) {261					self::$cache_expiration = self::$persistently_cache;262				}263			} else {264				wp_cache_add_non_persistent_groups( 'themes' );265			}266		}267 268		// Handle a numeric theme directory as a string.269		$theme_dir = (string) $theme_dir;270 271		$this->theme_root = $theme_root;272		$this->stylesheet = $theme_dir;273 274		// Correct a situation where the theme is 'some-directory/some-theme' but 'some-directory' was passed in as part of the theme root instead.275		if ( ! in_array( $theme_root, (array) $wp_theme_directories, true )276			&& in_array( dirname( $theme_root ), (array) $wp_theme_directories, true )277		) {278			$this->stylesheet = basename( $this->theme_root ) . '/' . $this->stylesheet;279			$this->theme_root = dirname( $theme_root );280		}281 282		$this->cache_hash = md5( $this->theme_root . '/' . $this->stylesheet );283		$theme_file       = $this->stylesheet . '/style.css';284 285		$cache = $this->cache_get( 'theme' );286 287		if ( is_array( $cache ) ) {288			foreach ( array( 'block_template_folders', 'block_theme', 'errors', 'headers', 'template' ) as $key ) {289				if ( isset( $cache[ $key ] ) ) {290					$this->$key = $cache[ $key ];291				}292			}293			if ( $this->errors ) {294				return;295			}296			if ( isset( $cache['theme_root_template'] ) ) {297				$theme_root_template = $cache['theme_root_template'];298			}299		} elseif ( ! file_exists( $this->theme_root . '/' . $theme_file ) ) {300			$this->headers['Name'] = $this->stylesheet;301			if ( ! file_exists( $this->theme_root . '/' . $this->stylesheet ) ) {302				$this->errors = new WP_Error(303					'theme_not_found',304					sprintf(305						/* translators: %s: Theme directory name. */306						__( 'The theme directory "%s" does not exist.' ),307						esc_html( $this->stylesheet )308					)309				);310			} else {311				$this->errors = new WP_Error( 'theme_no_stylesheet', __( 'Stylesheet is missing.' ) );312			}313			$this->template               = $this->stylesheet;314			$this->block_theme            = false;315			$this->block_template_folders = $this->default_template_folders;316			$this->cache_add(317				'theme',318				array(319					'block_template_folders' => $this->block_template_folders,320					'block_theme'            => $this->block_theme,321					'headers'                => $this->headers,322					'errors'                 => $this->errors,323					'stylesheet'             => $this->stylesheet,324					'template'               => $this->template,325				)326			);327			if ( ! file_exists( $this->theme_root ) ) { // Don't cache this one.328				$this->errors->add( 'theme_root_missing', __( '<strong>Error:</strong> The themes directory is either empty or does not exist. Please check your installation.' ) );329			}330			return;

Changelog

Introduced in 3.4.0. Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/class-wp-theme.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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