Defined (1)

The function is defined in the following location(s).

/wp-includes/theme.php  

function search_theme_directories( $force = false ) { 
    global $wp_theme_directories; 
    static $found_themes = null; 
 
    if ( empty( $wp_theme_directories ) ) 
        return false; 
 
    if ( ! $force && isset( $found_themes ) ) 
        return $found_themes; 
 
    $found_themes = array(); 
 
    $wp_theme_directories = (array) $wp_theme_directories; 
    $relative_theme_roots = array(); 
 
    // Set up maybe-relative, maybe-absolute array of theme directories. 
    // We always want to return absolute, but we need to cache relative 
    // to use in get_theme_root(). 
    foreach ( $wp_theme_directories as $theme_root ) { 
        if ( 0 === strpos( $theme_root, WP_CONTENT_DIR ) ) 
            $relative_theme_roots[ str_replace( WP_CONTENT_DIR, '', $theme_root ) ] = $theme_root; 
        else 
            $relative_theme_roots[ $theme_root ] = $theme_root; 
    } 
 
    /** 
     * Filters whether to get the cache of the registered theme directories. 
     * 
     * @since 3.4.0 
     * 
     * @param bool   $cache_expiration Whether to get the cache of the theme directories. Default false. 
     * @param string $cache_directory  Directory to be searched for the cache. 
     */ 
    if ( $cache_expiration = apply_filters( 'wp_cache_themes_persistently', false, 'search_theme_directories' ) ) { 
        $cached_roots = get_site_transient( 'theme_roots' ); 
        if ( is_array( $cached_roots ) ) { 
            foreach ( $cached_roots as $theme_dir => $theme_root ) { 
                // A cached theme root is no longer around, so skip it. 
                if ( ! isset( $relative_theme_roots[ $theme_root ] ) ) 
                    continue; 
                $found_themes[ $theme_dir ] = array( 
                    'theme_file' => $theme_dir . '/style.css',  
                    'theme_root' => $relative_theme_roots[ $theme_root ], // Convert relative to absolute. 
 ); 
            } 
            return $found_themes; 
        } 
        if ( ! is_int( $cache_expiration ) ) 
            $cache_expiration = 1800; // half hour 
    } else { 
        $cache_expiration = 1800; // half hour 
    } 
 
    /** Loop the registered theme directories and extract all themes */ 
    foreach ( $wp_theme_directories as $theme_root ) { 
 
        // Start with directories in the root of the current theme directory. 
        $dirs = @ scandir( $theme_root ); 
        if ( ! $dirs ) { 
            trigger_error( "$theme_root is not readable", E_USER_NOTICE ); 
            continue; 
        } 
        foreach ( $dirs as $dir ) { 
            if ( ! is_dir( $theme_root . '/' . $dir ) || $dir[0] == '.' || $dir == 'CVS' ) 
                continue; 
            if ( file_exists( $theme_root . '/' . $dir . '/style.css' ) ) { 
                // wp-content/themes/a-single-theme 
                // wp-content/themes is $theme_root, a-single-theme is $dir 
                $found_themes[ $dir ] = array( 
                    'theme_file' => $dir . '/style.css',  
                    'theme_root' => $theme_root,  
 ); 
            } else { 
                $found_theme = false; 
                // wp-content/themes/a-folder-of-themes/* 
                // wp-content/themes is $theme_root, a-folder-of-themes is $dir, then themes are $sub_dirs 
                $sub_dirs = @ scandir( $theme_root . '/' . $dir ); 
                if ( ! $sub_dirs ) { 
                    trigger_error( "$theme_root/$dir is not readable", E_USER_NOTICE ); 
                    continue; 
                } 
                foreach ( $sub_dirs as $sub_dir ) { 
                    if ( ! is_dir( $theme_root . '/' . $dir . '/' . $sub_dir ) || $dir[0] == '.' || $dir == 'CVS' ) 
                        continue; 
                    if ( ! file_exists( $theme_root . '/' . $dir . '/' . $sub_dir . '/style.css' ) ) 
                        continue; 
                    $found_themes[ $dir . '/' . $sub_dir ] = array( 
                        'theme_file' => $dir . '/' . $sub_dir . '/style.css',  
                        'theme_root' => $theme_root,  
 ); 
                    $found_theme = true; 
                } 
                // Never mind the above, it's just a theme missing a style.css. 
                // Return it; WP_Theme will catch the error. 
                if ( ! $found_theme ) 
                    $found_themes[ $dir ] = array( 
                        'theme_file' => $dir . '/style.css',  
                        'theme_root' => $theme_root,  
 ); 
            } 
        } 
    } 
 
    asort( $found_themes ); 
 
    $theme_roots = array(); 
    $relative_theme_roots = array_flip( $relative_theme_roots ); 
 
    foreach ( $found_themes as $theme_dir => $theme_data ) { 
        $theme_roots[ $theme_dir ] = $relative_theme_roots[ $theme_data['theme_root'] ]; // Convert absolute to relative. 
    } 
 
    if ( $theme_roots != get_site_transient( 'theme_roots' ) ) 
        set_site_transient( 'theme_roots', $theme_roots, $cache_expiration ); 
 
    return $found_themes; 
}