root/trunk/wp-includes/theme.php

<?php
/**
 * @package WordPress
 * @subpackage Themes
 * @since 0.0
 * Theme/template/stylesheet functions.
 */
function get_stylesheet() {
    return apply_filters('stylesheet', get_option('stylesheet'));
}

function get_stylesheet_directory() {
    $stylesheet = get_stylesheet();
    $stylesheet_dir = get_theme_root() . "/$stylesheet";
    return apply_filters('stylesheet_directory', $stylesheet_dir, $stylesheet);
}

function get_stylesheet_directory_uri() {
    $stylesheet = get_stylesheet();
    $stylesheet_dir_uri = get_theme_root_uri() . "/$stylesheet";
    return apply_filters('stylesheet_directory_uri', $stylesheet_dir_uri, $stylesheet);
}

function get_stylesheet_uri() {
    $stylesheet_dir_uri = get_stylesheet_directory_uri();
    $stylesheet_uri = $stylesheet_dir_uri . "/style.css";
    return apply_filters('stylesheet_uri', $stylesheet_uri, $stylesheet_dir_uri);
}

function get_locale_stylesheet_uri() {
    global $wp_locale;
    $stylesheet_dir_uri = get_stylesheet_directory_uri();
    $dir = get_stylesheet_directory();
    $locale = get_locale();
    if ( file_exists("$dir/$locale.css") )
        $stylesheet_uri = "$stylesheet_dir_uri/$locale.css";
    elseif ( !empty($wp_locale->text_direction) && file_exists("$dir/{$wp_locale->text_direction}.css") )
        $stylesheet_uri = "$stylesheet_dir_uri/{$wp_locale->text_direction}.css";
    else
        $stylesheet_uri = '';
    return apply_filters('locale_stylesheet_uri', $stylesheet_uri, $stylesheet_dir_uri);
}

function get_template() {
    return apply_filters('template', get_option('template'));
}

function get_template_directory() {
    $template = get_template();
    $template_dir = get_theme_root() . "/$template";
    return apply_filters('template_directory', $template_dir, $template);
}

function get_template_directory_uri() {
    $template = get_template();
    $template_dir_uri = get_theme_root_uri() . "/$template";
    return apply_filters('template_directory_uri', $template_dir_uri, $template);
}

function get_theme_data( $theme_file ) {
    $themes_allowed_tags = array(
        'a' => array(
            'href' => array(),'title' => array()
            ),
        'abbr' => array(
            'title' => array()
            ),
        'acronym' => array(
            'title' => array()
            ),
        'code' => array(),
        'em' => array(),
        'strong' => array()
    );

    $theme_data = implode( '', file( $theme_file ) );
    $theme_data = str_replace ( '\r', '\n', $theme_data );
    preg_match( '|Theme Name:(.*)$|mi', $theme_data, $theme_name );
    preg_match( '|Theme URI:(.*)$|mi', $theme_data, $theme_uri );
    preg_match( '|Description:(.*)$|mi', $theme_data, $description );

    if ( preg_match( '|Author URI:(.*)$|mi', $theme_data, $author_uri ) )
        $author_uri = clean_url( trim( $author_uri[1]) );
    else
        $author_uti = '';

    if ( preg_match( '|Template:(.*)$|mi', $theme_data, $template ) )
        $template = wp_kses( trim( $template[1] ), $themes_allowed_tags );
    else
        $template = '';

    if ( preg_match( '|Version:(.*)|i', $theme_data, $version ) )
        $version = wp_kses( trim( $version[1] ), $themes_allowed_tags );
    else
        $version = '';

    if ( preg_match('|Status:(.*)|i', $theme_data, $status) )
        $status = wp_kses( trim( $status[1] ), $themes_allowed_tags );
    else
        $status = 'publish';

    if ( preg_match('|Tags:(.*)|i', $theme_data, $tags) )
        $tags = array_map( 'trim', explode( ',', wp_kses( trim( $tags[1] ), array() ) ) );
    else
        $tags = array();

    $name = $theme = wp_kses( trim( $theme_name[1] ), $themes_allowed_tags );
    $theme_uri = clean_url( trim( $theme_uri[1] ) );
    $description = wptexturize( wp_kses( trim( $description[1] ), $themes_allowed_tags ) );

    if ( preg_match( '|Author:(.*)$|mi', $theme_data, $author_name ) ) {
        if ( empty( $author_uri ) ) {
            $author = wp_kses( trim( $author_name[1] ), $themes_allowed_tags );
        } else {
            $author = sprintf( '<a href="%1$s" title="%2$s">%3$s</a>', $author_uri, __( 'Visit author homepage' ), wp_kses( trim( $author_name[1] ), $themes_allowed_tags ) );
        }
    } else {
        $author = __('Anonymous');
    }

    return array( 'Name' => $name, 'Title' => $theme, 'URI' => $theme_uri, 'Description' => $description, 'Author' => $author, 'Version' => $version, 'Template' => $template, 'Status' => $status, 'Tags' => $tags );
}

function get_themes() {
    global $wp_themes, $wp_broken_themes;

    if ( isset($wp_themes) )
        return $wp_themes;

    $themes = array();
    $wp_broken_themes = array();
    $theme_loc = $theme_root = get_theme_root();
    if ( '/' != WP_CONTENT_DIR ) // don't want to replace all forward slashes, see Trac #4541
        $theme_loc = str_replace(WP_CONTENT_DIR, '', $theme_root);

    // Files in wp-content/themes directory and one subdir down
    $themes_dir = @ opendir($theme_root);
    if ( !$themes_dir )
        return false;

    while ( ($theme_dir = readdir($themes_dir)) !== false ) {
        if ( is_dir($theme_root . '/' . $theme_dir) && is_readable($theme_root . '/' . $theme_dir) ) {
            if ( $theme_dir{0} == '.' || $theme_dir == '..' || $theme_dir == 'CVS' )
                continue;
            $stylish_dir = @ opendir($theme_root . '/' . $theme_dir);
            $found_stylesheet = false;
            while ( ($theme_file = readdir($stylish_dir)) !== false ) {
                if ( $theme_file == 'style.css' ) {
                    $theme_files[] = $theme_dir . '/' . $theme_file;
                    $found_stylesheet = true;
                    break;
                }
            }
            @closedir($stylish_dir);
            if ( !$found_stylesheet ) { // look for themes in that dir
                $subdir = "$theme_root/$theme_dir";
                $subdir_name = $theme_dir;
                $theme_subdir = @ opendir( $subdir );
                while ( ($theme_dir = readdir($theme_subdir)) !== false ) {
                    if ( is_dir( $subdir . '/' . $theme_dir) && is_readable($subdir . '/' . $theme_dir) ) {
                        if ( $theme_dir{0} == '.' || $theme_dir == '..' || $theme_dir == 'CVS' )
                            continue;
                        $stylish_dir = @ opendir($subdir . '/' . $theme_dir);
                        $found_stylesheet = false;
                        while ( ($theme_file = readdir($stylish_dir)) !== false ) {
                            if ( $theme_file == 'style.css' ) {
                                $theme_files[] = $subdir_name . '/' . $theme_dir . '/' . $theme_file;
                                $found_stylesheet = true;
                                break;
                            }
                        }
                        @closedir($stylish_dir);
                    }
                }
                @closedir($theme_subdir);
                $wp_broken_themes[$theme_dir] = array('Name' => $theme_dir, 'Title' => $theme_dir, 'Description' => __('Stylesheet is missing.'));
            }
        }
    }
    if ( is_dir( $theme_dir ) )
        @closedir( $theme_dir );

    if ( !$themes_dir || !$theme_files )
        return $themes;

    sort($theme_files);

    foreach ( (array) $theme_files as $theme_file ) {
        if ( !is_readable("$theme_root/$theme_file") ) {
            $wp_broken_themes[$theme_file] = array('Name' => $theme_file, 'Title' => $theme_file, 'Description' => __('File not readable.'));
            continue;
        }

        $theme_data = get_theme_data("$theme_root/$theme_file");

        $name        = $theme_data['Name'];
        $title       = $theme_data['Title'];
        $description = wptexturize($theme_data['Description']);
        $version     = $theme_data['Version'];
        $author      = $theme_data['Author'];
        $template    = $theme_data['Template'];
        $stylesheet  = dirname($theme_file);

        $screenshot = false;
        foreach ( array('png', 'gif', 'jpg', 'jpeg') as $ext ) {
            if (file_exists("$theme_root/$stylesheet/screenshot.$ext")) {
                $screenshot = "screenshot.$ext";
                break;
            }
        }

        if ( empty($name) ) {
            $name = dirname($theme_file);
            $title = $name;
        }

        if ( empty($template) ) {
            if ( file_exists(dirname("$theme_root/$theme_file/index.php")) )
                $template = dirname($theme_file);
            else
                continue;
        }

        $template = trim($template);

        if ( !file_exists("$theme_root/$template/index.php") ) {
            $parent_dir = dirname(dirname($theme_file));
            if ( file_exists("$theme_root/$parent_dir/$template/index.php") ) {
                $template = "$parent_dir/$template";
            } else {
                $wp_broken_themes[$name] = array('Name' => $name, 'Title' => $title, 'Description' => __('Template is missing.'));
                continue;
            }
        }

        $stylesheet_files = array();
        $template_files = array();

        $stylesheet_dir = @ dir("$theme_root/$stylesheet");
        if ( $stylesheet_dir ) {
            while ( ($file = $stylesheet_dir->read()) !== false ) {
                if ( !preg_match('|^\.+$|', $file) ) {
                    if ( preg_match('|\.css$|', $file) )
                        $stylesheet_files[] = "$theme_loc/$stylesheet/$file";
                    elseif ( preg_match('|\.php$|', $file) )
                        $template_files[] = "$theme_loc/$stylesheet/$file";
                }
            }
        }

        $template_dir = @ dir("$theme_root/$template");
        if ( $template_dir ) {
            while(($file = $template_dir->read()) !== false) {
                if ( !preg_match('|^\.+$|', $file) && preg_match('|\.php$|', $file) )
                    $template_files[] = "$theme_loc/$template/$file";
            }
        }

        $template_dir = dirname($template_files[0]);
        $stylesheet_dir = dirname($stylesheet_files[0]);

        if ( empty($template_dir) )
            $template_dir = '/';
        if ( empty($stylesheet_dir) )
            $stylesheet_dir = '/';

        // Check for theme name collision.  This occurs if a theme is copied to
        // a new theme directory and the theme header is not updated.  Whichever
        // theme is first keeps the name.  Subsequent themes get a suffix applied.
        // The Default and Classic themes always trump their pretenders.
        if ( isset($themes[$name]) ) {
            if ( ('WordPress Default' == $name || 'WordPress Classic' == $name) &&
                     ('default' == $stylesheet || 'classic' == $stylesheet) ) {
                // If another theme has claimed to be one of our default themes, move
                // them aside.
                $suffix = $themes[$name]['Stylesheet'];
                $new_name = "$name/$suffix";
                $themes[$new_name] = $themes[$name];
                $themes[$new_name]['Name'] = $new_name;
            } else {
                $name = "$name/$stylesheet";
            }
        }

        $themes[$name] = array('Name' => $name, 'Title' => $title, 'Description' => $description, 'Author' => $author, 'Version' => $version, 'Template' => $template, 'Stylesheet' => $stylesheet, 'Template Files' => $template_files, 'Stylesheet Files' => $stylesheet_files, 'Template Dir' => $template_dir, 'Stylesheet Dir' => $stylesheet_dir, 'Status' => $theme_data['Status'], 'Screenshot' => $screenshot, 'Tags' => $theme_data['Tags']);
    }

    // Resolve theme dependencies.
    $theme_names = array_keys($themes);

    foreach ( (array) $theme_names as $theme_name ) {
        $themes[$theme_name]['Parent Theme'] = '';
        if ( $themes[$theme_name]['Stylesheet'] != $themes[$theme_name]['Template'] ) {
            foreach ( (array) $theme_names as $parent_theme_name ) {
                if ( ($themes[$parent_theme_name]['Stylesheet'] == $themes[$parent_theme_name]['Template']) && ($themes[$parent_theme_name]['Template'] == $themes[$theme_name]['Template']) ) {
                    $themes[$theme_name]['Parent Theme'] = $themes[$parent_theme_name]['Name'];
                    break;
                }
            }
        }
    }

    $wp_themes = $themes;

    return $themes;
}

function get_theme($theme) {
    $themes = get_themes();

    if ( array_key_exists($theme, $themes) )
        return $themes[$theme];

    return NULL;
}

function get_current_theme() {
    if ( $theme = get_option('current_theme') )
        return $theme;

    $themes = get_themes();
    $theme_names = array_keys($themes);
    $current_template = get_option('template');
    $current_stylesheet = get_option('stylesheet');
    $current_theme = 'WordPress Default';

    if ( $themes ) {
        foreach ( (array) $theme_names as $theme_name ) {
            if ( $themes[$theme_name]['Stylesheet'] == $current_stylesheet &&
                    $themes[$theme_name]['Template'] == $current_template ) {
                $current_theme = $themes[$theme_name]['Name'];
                break;
            }
        }
    }

    update_option('current_theme', $current_theme);

    return $current_theme;
}

function get_theme_root() {
    return apply_filters('theme_root', WP_CONTENT_DIR . "/themes");
}

function get_theme_root_uri() {
    return apply_filters('theme_root_uri', content_url('themes'), get_option('siteurl'));
}

function get_query_template($type) {
    $type = preg_replace( '|[^a-z0-9-]+|', '', $type );
    return apply_filters("{$type}_template", locate_template(array("{$type}.php")));
}

function get_404_template() {
    return get_query_template('404');
}

function get_archive_template() {
    return get_query_template('archive');
}

function get_author_template() {
    return get_query_template('author');
}

function get_category_template() {
    $template =locate_template(array("category-" . absint( get_query_var('cat') ) . '.php',"category.php"));
    return apply_filters('category_template', $template);
}

function get_tag_template() {
    $template = locate_template(array("tag-" . absint( get_query_var('tag') ) . '.php',"tag.php"));
    return apply_filters('tag_template', $template);
}

function get_taxonomy_template() {
    $taxonomy = get_query_var('taxonomy');
    $term = get_query_var('term');

    $templates = array();
    if ( $taxonomy && $term )
        $templates[] = "taxonomy-$taxonomy-$term.php";
    if ( $taxonomy )
        $templates[] = "taxonomy-$taxonomy.php";
    
    $templates[] = "taxonomy.php";

    $template = locate_template($templates);
    return apply_filters('taxonomy_template', $template);
}

function get_date_template() {
    return get_query_template('date');
}

function get_home_template() {
    $template = locate_template(array('home.php','index.php'));
    return apply_filters('home_template', $template);
}

function get_page_template() {
    global $wp_query;

    $id = (int) $wp_query->post->ID;
    $template = get_post_meta($id, '_wp_page_template', true);

    if ( 'default' == $template )
        $template = '';

    $templates = array();
    if ( !empty($template) && !validate_file($template) )
        $templates[] = $template;
    
    $templates[] = "page.php";

    return apply_filters('page_template', locate_template($templates));
}

function get_paged_template() {
    return get_query_template('paged');
}

function get_search_template() {
    return get_query_template('search');
}

function get_single_template() {
    return get_query_template('single');
}

function get_attachment_template() {
    global $posts;
    $type = explode('/', $posts[0]->post_mime_type);
    if ( $template = get_query_template($type[0]) )
        return $template;
    elseif ( $template = get_query_template($type[1]) )
        return $template;
    elseif ( $template = get_query_template("$type[0]_$type[1]") )
        return $template;
    else
        return get_query_template('attachment');
}

function get_comments_popup_template() {
    $template = locate_template(array("comments-popup.php"));
    if ('' == $template)
        $template = get_theme_root() . '/default/comments-popup.php';

    return apply_filters('comments_popup_template', $template);
}

/**
 * Returns the name of the highest priority template file that exists
 * 
 * Searches in the STYLESHEETPATH before TEMPLATEPATH so that themes which
 * inherit from a parent theme can just overload one file.
 * @since 2.7
 *
 * @param array $template_names Array of template files to search for in priority order
 * @param bool $load If true the template file will be loaded if it is found.
 * @return string The template filename if one is located.
 */
function locate_template($template_names, $load = false) {
    if (!is_array($template_names))
        return '';
    
    $located = '';
    foreach($template_names as $template_name) {
        if ( file_exists(STYLESHEETPATH . '/' . $template_name)) {
            $located = STYLESHEETPATH . '/' . $template_name;
            break;
        } else if ( file_exists(TEMPLATEPATH . '/' . $template_name) ) {
            $located = TEMPLATEPATH . '/' . $template_name;