Wordpress 3.0.6-scripts
[autoinstalls/wordpress.git] / wp-includes / theme.php
index 9d56a6403d0f8a801276a49c8ef9360f3a509c94..10195c81b4ea48a0ee839ebb5c3b1232c93b913a 100644 (file)
@@ -6,6 +6,17 @@
  * @subpackage Template
  */
 
+/**
+ * Whether a child theme is in use.
+ *
+ * @since 3.0.0
+ *
+ * @return bool true if a child theme is in use, false otherwise.
+ **/
+function is_child_theme() {
+       return ( TEMPLATEPATH !== STYLESHEETPATH );
+}
+
 /**
  * Retrieve name of the current stylesheet.
  *
@@ -34,8 +45,10 @@ function get_stylesheet() {
  */
 function get_stylesheet_directory() {
        $stylesheet = get_stylesheet();
-       $stylesheet_dir = get_theme_root() . "/$stylesheet";
-       return apply_filters('stylesheet_directory', $stylesheet_dir, $stylesheet);
+       $theme_root = get_theme_root( $stylesheet );
+       $stylesheet_dir = "$theme_root/$stylesheet";
+
+       return apply_filters( 'stylesheet_directory', $stylesheet_dir, $stylesheet, $theme_root );
 }
 
 /**
@@ -47,8 +60,10 @@ function get_stylesheet_directory() {
  */
 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);
+       $theme_root_uri = get_theme_root_uri( $stylesheet );
+       $stylesheet_dir_uri = "$theme_root_uri/$stylesheet";
+
+       return apply_filters( 'stylesheet_directory_uri', $stylesheet_dir_uri, $stylesheet, $theme_root_uri );
 }
 
 /**
@@ -123,8 +138,10 @@ function get_template() {
  */
 function get_template_directory() {
        $template = get_template();
-       $template_dir = get_theme_root() . "/$template";
-       return apply_filters('template_directory', $template_dir, $template);
+       $theme_root = get_theme_root( $template );
+       $template_dir = "$theme_root/$template";
+
+       return apply_filters( 'template_directory', $template_dir, $template, $theme_root );
 }
 
 /**
@@ -137,8 +154,10 @@ function get_template_directory() {
  */
 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);
+       $theme_root_uri = get_theme_root_uri( $template );
+       $template_dir_uri = "$theme_root_uri/$template";
+
+       return apply_filters( 'template_directory_uri', $template_dir_uri, $template, $theme_root_uri );
 }
 
 /**
@@ -162,6 +181,18 @@ function get_template_directory_uri() {
  * @return array Theme data.
  */
 function get_theme_data( $theme_file ) {
+       $default_headers = array(
+               'Name' => 'Theme Name',
+               'URI' => 'Theme URI',
+               'Description' => 'Description',
+               'Author' => 'Author',
+               'AuthorURI' => 'Author URI',
+               'Version' => 'Version',
+               'Template' => 'Template',
+               'Status' => 'Status',
+               'Tags' => 'Tags'
+               );
+
        $themes_allowed_tags = array(
                'a' => array(
                        'href' => array(),'title' => array()
@@ -177,59 +208,42 @@ function get_theme_data( $theme_file ) {
                'strong' => array()
        );
 
-       $theme_data = implode( '', file( $theme_file ) );
-       $theme_data = str_replace ( '\r', '\n', $theme_data );
-       if ( preg_match( '|Theme Name:(.*)$|mi', $theme_data, $theme_name ) )
-               $name = $theme = wp_kses( _cleanup_header_comment($theme_name[1]), $themes_allowed_tags );
-       else
-               $name = $theme = '';
+       $theme_data = get_file_data( $theme_file, $default_headers, 'theme' );
 
-       if ( preg_match( '|Theme URI:(.*)$|mi', $theme_data, $theme_uri ) )
-               $theme_uri = esc_url( _cleanup_header_comment($theme_uri[1]) );
-       else
-               $theme_uri = '';
+       $theme_data['Name'] = $theme_data['Title'] = wp_kses( $theme_data['Name'], $themes_allowed_tags );
 
-       if ( preg_match( '|Description:(.*)$|mi', $theme_data, $description ) )
-               $description = wptexturize( wp_kses( _cleanup_header_comment($description[1]), $themes_allowed_tags ) );
-       else
-               $description = '';
+       $theme_data['URI'] = esc_url( $theme_data['URI'] );
 
-       if ( preg_match( '|Author URI:(.*)$|mi', $theme_data, $author_uri ) )
-               $author_uri = esc_url( _cleanup_header_comment($author_uri[1]) );
-       else
-               $author_uri = '';
+       $theme_data['Description'] = wptexturize( wp_kses( $theme_data['Description'], $themes_allowed_tags ) );
 
-       if ( preg_match( '|Template:(.*)$|mi', $theme_data, $template ) )
-               $template = wp_kses( _cleanup_header_comment($template[1]), $themes_allowed_tags );
-       else
-               $template = '';
+       $theme_data['AuthorURI'] = esc_url( $theme_data['AuthorURI'] );
 
-       if ( preg_match( '|Version:(.*)|i', $theme_data, $version ) )
-               $version = wp_kses( _cleanup_header_comment($version[1]), $themes_allowed_tags );
-       else
-               $version = '';
+       $theme_data['Template'] = wp_kses( $theme_data['Template'], $themes_allowed_tags );
 
-       if ( preg_match('|Status:(.*)|i', $theme_data, $status) )
-               $status = wp_kses( _cleanup_header_comment($status[1]), $themes_allowed_tags );
+       $theme_data['Version'] = wp_kses( $theme_data['Version'], $themes_allowed_tags );
+
+       if ( $theme_data['Status'] == '' )
+               $theme_data['Status'] = 'publish';
        else
-               $status = 'publish';
+               $theme_data['Status'] = wp_kses( $theme_data['Status'], $themes_allowed_tags );
 
-       if ( preg_match('|Tags:(.*)|i', $theme_data, $tags) )
-               $tags = array_map( 'trim', explode( ',', wp_kses( _cleanup_header_comment($tags[1]), array() ) ) );
+       if ( $theme_data['Tags'] == '' )
+               $theme_data['Tags'] = array();
        else
-               $tags = array();
+               $theme_data['Tags'] = array_map( 'trim', explode( ',', wp_kses( $theme_data['Tags'], array() ) ) );
 
-       if ( preg_match( '|Author:(.*)$|mi', $theme_data, $author_name ) ) {
-               if ( empty( $author_uri ) ) {
-                       $author = wp_kses( _cleanup_header_comment($author_name[1]), $themes_allowed_tags );
+       if ( $theme_data['Author'] == '' ) {
+               $theme_data['Author'] = $theme_data['AuthorName'] = __('Anonymous');
+       } else {
+               $theme_data['AuthorName'] = wp_kses( $theme_data['Author'], $themes_allowed_tags );
+               if ( empty( $theme_data['AuthorURI'] ) ) {
+                       $theme_data['Author'] = $theme_data['AuthorName'];
                } else {
-                       $author = sprintf( '<a href="%1$s" title="%2$s">%3$s</a>', $author_uri, __( 'Visit author homepage' ), wp_kses( _cleanup_header_comment($author_name[1]), $themes_allowed_tags ) );
+                       $theme_data['Author'] = sprintf( '<a href="%1$s" title="%2$s">%3$s</a>', $theme_data['AuthorURI'], __( 'Visit author homepage' ), $theme_data['AuthorName'] );
                }
-       } else {
-               $author = __('Anonymous');
        }
 
-       return array( 'Name' => $name, 'Title' => $theme, 'URI' => $theme_uri, 'Description' => $description, 'Author' => $author, 'Version' => $version, 'Template' => $template, 'Status' => $status, 'Tags' => $tags );
+       return $theme_data;
 }
 
 /**
@@ -253,65 +267,20 @@ function get_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);
+       /* Register the default root as a theme directory */
+       register_theme_directory( get_theme_root() );
 
-       // Files in wp-content/themes directory and one subdir down
-       $themes_dir = @ opendir($theme_root);
-       if ( !$themes_dir )
+       if ( !$theme_files = search_theme_directories() )
                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;
+       asort( $theme_files );
 
-       sort($theme_files);
+       $wp_themes = array();
 
        foreach ( (array) $theme_files as $theme_file ) {
+               $theme_root = $theme_file['theme_root'];
+               $theme_file = $theme_file['theme_file'];
+
                if ( !is_readable("$theme_root/$theme_file") ) {
                        $wp_broken_themes[$theme_file] = array('Name' => $theme_file, 'Title' => $theme_file, 'Description' => __('File not readable.'));
                        continue;
@@ -340,23 +309,40 @@ function get_themes() {
                        $title = $name;
                }
 
+               $parent_template = $template;
+
                if ( empty($template) ) {
-                       if ( file_exists(dirname("$theme_root/$theme_file/index.php")) )
-                               $template = dirname($theme_file);
+                       if ( file_exists("$theme_root/$stylesheet/index.php") )
+                               $template = $stylesheet;
                        else
                                continue;
                }
 
-               $template = trim($template);
+               $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";
+                               $template_directory = "$theme_root/$template";
                        } else {
-                               $wp_broken_themes[$name] = array('Name' => $name, 'Title' => $title, 'Description' => __('Template is missing.'));
-                               continue;
+                               /**
+                                * The parent theme doesn't exist in the current theme's folder or sub folder
+                                * so lets use the theme root for the parent template.
+                                */
+                               if ( isset($theme_files[$template]) && file_exists( $theme_files[$template]['theme_root'] . "/$template/index.php" ) ) {
+                                       $template_directory = $theme_files[$template]['theme_root'] . "/$template";
+                               } else {
+                                       if ( empty( $parent_template) )
+                                               $wp_broken_themes[$name] = array('Name' => $name, 'Title' => $title, 'Description' => __('Template is missing.'), 'error' => 'no_template');
+                                       else
+                                               $wp_broken_themes[$name] = array('Name' => $name, 'Title' => $title, 'Description' => sprintf( __('The parent theme is missing. Please install the "%s" parent theme.'),  $parent_template ), 'error' => 'no_parent', 'parent' => $parent_template );
+                                       continue;
+                               }
+
                        }
+               } else {
+                       $template_directory = trim( $theme_root . '/' . $template );
                }
 
                $stylesheet_files = array();
@@ -367,28 +353,30 @@ function get_themes() {
                        while ( ($file = $stylesheet_dir->read()) !== false ) {
                                if ( !preg_match('|^\.+$|', $file) ) {
                                        if ( preg_match('|\.css$|', $file) )
-                                               $stylesheet_files[] = "$theme_loc/$stylesheet/$file";
+                                               $stylesheet_files[] = "$theme_root/$stylesheet/$file";
                                        elseif ( preg_match('|\.php$|', $file) )
-                                               $template_files[] = "$theme_loc/$stylesheet/$file";
+                                               $template_files[] = "$theme_root/$stylesheet/$file";
                                }
                        }
                        @ $stylesheet_dir->close();
                }
 
-               $template_dir = @ dir("$theme_root/$template");
+               $template_dir = @ dir("$template_directory");
                if ( $template_dir ) {
                        while ( ($file = $template_dir->read()) !== false ) {
                                if ( preg_match('|^\.+$|', $file) )
                                        continue;
                                if ( preg_match('|\.php$|', $file) ) {
-                                       $template_files[] = "$theme_loc/$template/$file";
-                               } elseif ( is_dir("$theme_root/$template/$file") ) {
-                                       $template_subdir = @ dir("$theme_root/$template/$file");
+                                       $template_files[] = "$template_directory/$file";
+                               } elseif ( is_dir("$template_directory/$file") ) {
+                                       $template_subdir = @ dir("$template_directory/$file");
+                                       if ( !$template_subdir )
+                                               continue;
                                        while ( ($subfile = $template_subdir->read()) !== false ) {
                                                if ( preg_match('|^\.+$|', $subfile) )
                                                        continue;
                                                if ( preg_match('|\.php$|', $subfile) )
-                                                       $template_files[] = "$theme_loc/$template/$file/$subfile";
+                                                       $template_files[] = "$template_directory/$file/$subfile";
                                        }
                                        @ $template_subdir->close();
                                }
@@ -396,6 +384,10 @@ function get_themes() {
                        @ $template_dir->close();
                }
 
+               //Make unique and remove duplicates when stylesheet and template are the same i.e. most themes
+               $template_files = array_unique($template_files);
+               $stylesheet_files = array_unique($stylesheet_files);
+
                $template_dir = dirname($template_files[0]);
                $stylesheet_dir = dirname($stylesheet_files[0]);
 
@@ -408,41 +400,81 @@ function get_themes() {
                // 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 ( isset($wp_themes[$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'];
+                               $suffix = $wp_themes[$name]['Stylesheet'];
                                $new_name = "$name/$suffix";
-                               $themes[$new_name] = $themes[$name];
-                               $themes[$new_name]['Name'] = $new_name;
+                               $wp_themes[$new_name] = $wp_themes[$name];
+                               $wp_themes[$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']);
+               $theme_roots[$stylesheet] = str_replace( WP_CONTENT_DIR, '', $theme_root );
+               $wp_themes[$name] = array(
+                       'Name' => $name,
+                       'Title' => $title,
+                       'Description' => $description,
+                       'Author' => $author,
+                       'Author Name' => $theme_data['AuthorName'],
+                       'Author URI' => $theme_data['AuthorURI'],
+                       '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'],
+                       'Theme Root' => $theme_root,
+                       'Theme Root URI' => str_replace( WP_CONTENT_DIR, content_url(), $theme_root ),
+               );
        }
 
-       // Resolve theme dependencies.
-       $theme_names = array_keys($themes);
+       unset($theme_files);
 
+       /* Store theme roots in the DB */
+       if ( get_site_transient( 'theme_roots' ) != $theme_roots )
+               set_site_transient( 'theme_roots', $theme_roots, 7200 ); // cache for two hours
+       unset($theme_roots);
+
+       /* Resolve theme dependencies. */
+       $theme_names = array_keys( $wp_themes );
        foreach ( (array) $theme_names as $theme_name ) {
-               $themes[$theme_name]['Parent Theme'] = '';
-               if ( $themes[$theme_name]['Stylesheet'] != $themes[$theme_name]['Template'] ) {
+               $wp_themes[$theme_name]['Parent Theme'] = '';
+               if ( $wp_themes[$theme_name]['Stylesheet'] != $wp_themes[$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'];
+                               if ( ($wp_themes[$parent_theme_name]['Stylesheet'] == $wp_themes[$parent_theme_name]['Template']) && ($wp_themes[$parent_theme_name]['Template'] == $wp_themes[$theme_name]['Template']) ) {
+                                       $wp_themes[$theme_name]['Parent Theme'] = $wp_themes[$parent_theme_name]['Name'];
                                        break;
                                }
                        }
                }
        }
 
-       $wp_themes = $themes;
+       return $wp_themes;
+}
 
-       return $themes;
+/**
+ * Retrieve theme roots.
+ *
+ * @since 2.9.0
+ *
+ * @return array Theme roots
+ */
+function get_theme_roots() {
+       $theme_roots = get_site_transient( 'theme_roots' );
+       if ( false === $theme_roots ) {
+               get_themes();
+               $theme_roots = get_site_transient( 'theme_roots' ); // this is set in get_theme()
+       }
+       return $theme_roots;
 }
 
 /**
@@ -498,18 +530,139 @@ function get_current_theme() {
        return $current_theme;
 }
 
+/**
+ * Register a directory that contains themes.
+ *
+ * @since 2.9.0
+ *
+ * @param string $directory Either the full filesystem path to a theme folder or a folder within WP_CONTENT_DIR
+ * @return bool
+ */
+function register_theme_directory( $directory) {
+       global $wp_theme_directories;
+
+       /* If this folder does not exist, return and do not register */
+       if ( !file_exists( $directory ) )
+                       /* Try prepending as the theme directory could be relative to the content directory */
+               $registered_directory = WP_CONTENT_DIR . '/' . $directory;
+       else
+               $registered_directory = $directory;
+
+       /* If this folder does not exist, return and do not register */
+       if ( !file_exists( $registered_directory ) )
+               return false;
+
+       $wp_theme_directories[] = $registered_directory;
+
+       return true;
+}
+
+/**
+ * Search all registered theme directories for complete and valid themes.
+ *
+ * @since 2.9.0
+ *
+ * @return array Valid themes found
+ */
+function search_theme_directories() {
+       global $wp_theme_directories, $wp_broken_themes;
+       if ( empty( $wp_theme_directories ) )
+               return false;
+
+       $theme_files = array();
+       $wp_broken_themes = array();
+
+       /* Loop the registered theme directories and extract all themes */
+       foreach ( (array) $wp_theme_directories as $theme_root ) {
+               $theme_loc = $theme_root;
+
+               /* We don't want to replace all forward slashes, see Trac #4541 */
+               if ( '/' != WP_CONTENT_DIR )
+                       $theme_loc = str_replace(WP_CONTENT_DIR, '', $theme_root);
+
+               /* Files in the root of the current theme 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 == '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] = array( 'theme_file' => $theme_dir . '/' . $theme_file, 'theme_root' => $theme_root );
+                                               $found_stylesheet = true;
+                                               break;
+                                       }
+                               }
+                               @closedir($stylish_dir);
+
+                               if ( !$found_stylesheet ) { // look for themes in that dir
+                                       $subdir = "$theme_root/$theme_dir";
+                                       $subdir_name = $theme_dir;
+                                       $theme_subdirs = @opendir( $subdir );
+
+                                       $found_subdir_themes = false;
+                                       while ( ($theme_subdir = readdir($theme_subdirs)) !== false ) {
+                                               if ( is_dir( $subdir . '/' . $theme_subdir) && is_readable($subdir . '/' . $theme_subdir) ) {
+                                                       if ( $theme_subdir{0} == '.' || $theme_subdir == 'CVS' )
+                                                               continue;
+
+                                                       $stylish_dir = @opendir($subdir . '/' . $theme_subdir);
+                                                       $found_stylesheet = false;
+
+                                                       while ( ($theme_file = readdir($stylish_dir)) !== false ) {
+                                                               if ( $theme_file == 'style.css' ) {
+                                                                       $theme_files["$theme_dir/$theme_subdir"] = array( 'theme_file' => $subdir_name . '/' . $theme_subdir . '/' . $theme_file, 'theme_root' => $theme_root );
+                                                                       $found_stylesheet = true;
+                                                                       $found_subdir_themes = true;
+                                                                       break;
+                                                               }
+                                                       }
+                                                       @closedir($stylish_dir);
+                                               }
+                                       }
+                                       @closedir($theme_subdirs);
+                                       if ( !$found_subdir_themes )
+                                               $wp_broken_themes[$theme_dir] = array('Name' => $theme_dir, 'Title' => $theme_dir, 'Description' => __('Stylesheet is missing.'));
+                               }
+                       }
+               }
+               @closedir( $themes_dir );
+       }
+       return $theme_files;
+}
+
 /**
  * Retrieve path to themes directory.
  *
  * Does not have trailing slash.
  *
  * @since 1.5.0
+ * @param $stylesheet_or_template The stylesheet or template name of the theme
  * @uses apply_filters() Calls 'theme_root' filter on path.
  *
  * @return string Theme path.
  */
-function get_theme_root() {
-       return apply_filters('theme_root', WP_CONTENT_DIR . "/themes");
+function get_theme_root( $stylesheet_or_template = false ) {
+       if ($stylesheet_or_template) {
+               $theme_roots = get_theme_roots();
+
+               if ( ! empty( $theme_roots[$stylesheet_or_template] ) )
+                       $theme_root = WP_CONTENT_DIR . $theme_roots[$stylesheet_or_template];
+               else
+                       $theme_root = WP_CONTENT_DIR . '/themes';
+       } else {
+               $theme_root = WP_CONTENT_DIR . '/themes';
+       }
+
+       return apply_filters( 'theme_root', $theme_root );
 }
 
 /**
@@ -518,11 +671,19 @@ function get_theme_root() {
  * Does not have trailing slash.
  *
  * @since 1.5.0
+ * @param $stylesheet_or_template The stylesheet or template name of the theme
  *
  * @return string Themes URI.
  */
-function get_theme_root_uri() {
-       return apply_filters('theme_root_uri', content_url('themes'), get_option('siteurl'));
+function get_theme_root_uri( $stylesheet_or_template = false ) {
+       $theme_roots = get_theme_roots();
+
+       if ( isset( $theme_roots[$stylesheet_or_template] ) && $theme_roots[$stylesheet_or_template] )
+               $theme_root_uri = content_url( $theme_roots[$stylesheet_or_template] );
+       else
+               $theme_root_uri = content_url( 'themes' );
+
+       return apply_filters( 'theme_root_uri', $theme_root_uri, get_option('siteurl'), $stylesheet_or_template );
 }
 
 /**
@@ -554,6 +715,17 @@ function get_query_template($type) {
        return apply_filters("{$type}_template", locate_template(array("{$type}.php")));
 }
 
+/**
+ * Retrieve path of index template in current or parent template.
+ *
+ * @since 3.0.0
+ *
+ * @return string
+ */
+function get_index_template() {
+       return get_query_template('index');
+}
+
 /**
  * Retrieve path of 404 template in current or parent template.
  *
@@ -584,15 +756,28 @@ function get_archive_template() {
  * @return string
  */
 function get_author_template() {
-       return get_query_template('author');
+       $author_id = absint( get_query_var( 'author' ) );
+       $author = get_user_by( 'id', $author_id );
+       $author = $author->user_nicename;
+
+       $templates = array();
+
+       if ( $author )
+               $templates[] = "author-{$author}.php";
+       if ( $author_id )
+               $templates[] = "author-{$author_id}.php";
+       $templates[] = 'author.php';
+
+       $template = locate_template( $templates );
+       return apply_filters( 'author_template', $template );
 }
 
 /**
  * Retrieve path of category template in current or parent template.
  *
- * Works by retrieving the current category ID, for example 'category-1.php' and
- * will fallback to category.php template, if the ID category file doesn't
- * exist.
+ * Works by first retrieving the current slug for example 'category-default.php' and then
+ * trying category ID, for example 'category-1.php' and will finally fallback to category.php
+ * template, if those files don't exist.
  *
  * @since 1.5.0
  * @uses apply_filters() Calls 'category_template' on file path of category template.
@@ -600,15 +785,27 @@ function get_author_template() {
  * @return string
  */
 function get_category_template() {
-       $template = locate_template(array("category-" . absint( get_query_var('cat') ) . '.php', 'category.php'));
+       $cat_ID = absint( get_query_var('cat') );
+       $category = get_category( $cat_ID );
+
+       $templates = array();
+
+       if ( !is_wp_error($category) )
+               $templates[] = "category-{$category->slug}.php";
+
+       $templates[] = "category-$cat_ID.php";
+       $templates[] = "category.php";
+
+       $template = locate_template($templates);
        return apply_filters('category_template', $template);
 }
 
 /**
  * Retrieve path of tag template in current or parent template.
  *
- * Works by retrieving the current tag name, for example 'tag-wordpress.php' and will
- * fallback to tag.php template, if the name tag file doesn't exist.
+ * Works by first retrieving the current tag name, for example 'tag-wordpress.php' and then
+ * trying tag ID, for example 'tag-1.php' and will finally fallback to tag.php
+ * template, if those files don't exist.
  *
  * @since 2.3.0
  * @uses apply_filters() Calls 'tag_template' on file path of tag template.
@@ -616,7 +813,18 @@ function get_category_template() {
  * @return string
  */
 function get_tag_template() {
-       $template = locate_template(array("tag-" . get_query_var('tag') . '.php', 'tag.php'));
+       $tag_id = absint( get_query_var('tag_id') );
+       $tag_name = get_query_var('tag');
+
+       $templates = array();
+
+       if ( $tag_name )
+               $templates[] = "tag-$tag_name.php";
+       if ( $tag_id )
+               $templates[] = "tag-$tag_id.php";
+       $templates[] = "tag.php";
+
+       $template = locate_template($templates);
        return apply_filters('tag_template', $template);
 }
 
@@ -667,6 +875,8 @@ function get_date_template() {
 /**
  * Retrieve path of home template in current or parent template.
  *
+ * This is the template used for the page containing the blog posts
+ *
  * Attempts to locate 'home.php' first before falling back to 'index.php'.
  *
  * @since 1.5.0
@@ -679,12 +889,26 @@ function get_home_template() {
        return apply_filters('home_template', $template);
 }
 
+/**
+ * Retrieve path of front-page template in current or parent template.
+ *
+ * Looks for 'front-page.php'.
+ *
+ * @since 3.0.0
+ * @uses apply_filters() Calls 'front_page_template' on file path of template.
+ *
+ * @return string
+ */
+function get_front_page_template() {
+       return apply_filters( 'front_page_template', locate_template( array('front-page.php') ) );
+}
+
 /**
  * Retrieve path of page template in current or parent template.
  *
- * First attempt is to look for the file in the '_wp_page_template' page meta
- * data. The second attempt, if the first has a file and is not empty, is to
- * look for 'page.php'.
+ * Will first look for the specifically assigned page template
+ * The will search for 'page-{slug}.php' followed by 'page-id.php'
+ * and finally 'page.php'
  *
  * @since 1.5.0
  *
@@ -693,8 +917,15 @@ function get_home_template() {
 function get_page_template() {
        global $wp_query;
 
-       $id = (int) $wp_query->post->ID;
+       $id = (int) $wp_query->get_queried_object_id();
        $template = get_post_meta($id, '_wp_page_template', true);
+       $pagename = get_query_var('pagename');
+
+       if ( !$pagename && $id > 0 ) {
+               // If a static page is set as the front page, $pagename will not be set. Retrieve it from the queried object
+               $post = $wp_query->get_queried_object();
+               $pagename = $post->post_name;
+       }
 
        if ( 'default' == $template )
                $template = '';
@@ -702,7 +933,10 @@ function get_page_template() {
        $templates = array();
        if ( !empty($template) && !validate_file($template) )
                $templates[] = $template;
-
+       if ( $pagename )
+               $templates[] = "page-$pagename.php";
+       if ( $id )
+               $templates[] = "page-$id.php";
        $templates[] = "page.php";
 
        return apply_filters('page_template', locate_template($templates));
@@ -738,7 +972,11 @@ function get_search_template() {
  * @return string
  */
 function get_single_template() {
-       return get_query_template('single');
+       global $wp_query;
+
+       $object = $wp_query->get_queried_object();
+       $templates = array('single-' . $object->post_type . '.php', 'single.php');
+       return apply_filters('single_template', locate_template($templates));
 }
 
 /**
@@ -773,9 +1011,7 @@ function get_attachment_template() {
  * Retrieve path of comment popup template in current or parent template.
  *
  * Checks for comment popup template in current template, if it exists or in the
- * parent template. If it doesn't exist, then it retrieves the comment-popup.php
- * file from the default theme. The default theme must then exist for it to
- * work.
+ * parent template.
  *
  * @since 1.5.0
  * @uses apply_filters() Calls 'comments_popup_template' filter on path.
@@ -784,8 +1020,10 @@ function get_attachment_template() {
  */
 function get_comments_popup_template() {
        $template = locate_template(array("comments-popup.php"));
+
+       // Backward compat code will be removed in a future release
        if ('' == $template)
-               $template = get_theme_root() . '/default/comments-popup.php';
+               $template = ABSPATH . WPINC . '/theme-compat/comments-popup.php';
 
        return apply_filters('comments_popup_template', $template);
 }
@@ -800,14 +1038,17 @@ function get_comments_popup_template() {
  *
  * @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.
+ * @param bool $require_once Whether to require_once or require. Default true. Has no effect if $load is false.
  * @return string The template filename if one is located.
  */
-function locate_template($template_names, $load = false) {
-       if (!is_array($template_names))
+function locate_template($template_names, $load = false, $require_once = true ) {
+       if ( !is_array($template_names) )
                return '';
 
        $located = '';
-       foreach($template_names as $template_name) {
+       foreach ( $template_names as $template_name ) {
+               if ( !$template_name )
+                       continue;
                if ( file_exists(STYLESHEETPATH . '/' . $template_name)) {
                        $located = STYLESHEETPATH . '/' . $template_name;
                        break;
@@ -817,14 +1058,14 @@ function locate_template($template_names, $load = false) {
                }
        }
 
-       if ($load && '' != $located)
-               load_template($located);
+       if ( $load && '' != $located )
+               load_template( $located, $require_once );
 
        return $located;
 }
 
 /**
- * Require once the template file with WordPress environment.
+ * Require the template file with WordPress environment.
  *
  * The globals are set up for the template file to ensure that the WordPress
  * environment is available from within the function. The query variables are
@@ -833,14 +1074,18 @@ function locate_template($template_names, $load = false) {
  * @since 1.5.0
  *
  * @param string $_template_file Path to template file.
+ * @param bool $require_once Whether to require_once or require. Default true.
  */
-function load_template($_template_file) {
+function load_template( $_template_file, $require_once = true ) {
        global $posts, $post, $wp_did_header, $wp_did_template_redirect, $wp_query, $wp_rewrite, $wpdb, $wp_version, $wp, $id, $comment, $user_ID;
 
-       if ( is_array($wp_query->query_vars) )
-               extract($wp_query->query_vars, EXTR_SKIP);
+       if ( is_array( $wp_query->query_vars ) )
+               extract( $wp_query->query_vars, EXTR_SKIP );
 
-       require_once($_template_file);
+       if ( $require_once )
+               require_once( $_template_file );
+       else
+               require( $_template_file );
 }
 
 /**
@@ -861,7 +1106,7 @@ function locale_stylesheet() {
  * Will only preform task if the user has permissions and template and preview
  * query variables exist.
  *
- * @since 2.5.0
+ * @since 2.6.0
  */
 function preview_theme() {
        if ( ! (isset($_GET['template']) && isset($_GET['preview'])) )
@@ -875,26 +1120,50 @@ function preview_theme() {
        if ( validate_file($_GET['template']) )
                return;
 
-       add_filter( 'template', create_function('', "return '{$_GET['template']}';") );
+       add_filter( 'template', '_preview_theme_template_filter' );
 
        if ( isset($_GET['stylesheet']) ) {
                $_GET['stylesheet'] = preg_replace('|[^a-z0-9_./-]|i', '', $_GET['stylesheet']);
                if ( validate_file($_GET['stylesheet']) )
                        return;
-               add_filter( 'stylesheet', create_function('', "return '{$_GET['stylesheet']}';") );
+               add_filter( 'stylesheet', '_preview_theme_stylesheet_filter' );
        }
 
        // Prevent theme mods to current theme being used on theme being previewed
-       add_filter( 'pre_option_mods_' . get_current_theme(), create_function( '', "return array();" ) );
+       add_filter( 'pre_option_mods_' . get_current_theme(), '__return_empty_array' );
 
        ob_start( 'preview_theme_ob_filter' );
 }
 add_action('setup_theme', 'preview_theme');
 
+/**
+ * Private function to modify the current template when previewing a theme
+ *
+ * @since 2.9.0
+ * @access private
+ *
+ * @return string
+ */
+function _preview_theme_template_filter() {
+       return isset($_GET['template']) ? $_GET['template'] : '';
+}
+
+/**
+ * Private function to modify the current stylesheet when previewing a theme
+ *
+ * @since 2.9.0
+ * @access private
+ *
+ * @return string
+ */
+function _preview_theme_stylesheet_filter() {
+       return isset($_GET['stylesheet']) ? $_GET['stylesheet'] : '';
+}
+
 /**
  * Callback function for ob_start() to capture all links in the theme.
  *
- * @since unknown
+ * @since 2.6.0
  * @access private
  *
  * @param string $content
@@ -909,7 +1178,7 @@ function preview_theme_ob_filter( $content ) {
  *
  * Callback function for preg_replace_callback() to accept and filter matches.
  *
- * @since unknown
+ * @since 2.6.0
  * @access private
  *
  * @param array $matches
@@ -921,7 +1190,7 @@ function preview_theme_ob_filter_callback( $matches ) {
        if (
                ( false !== strpos($matches[3], '/wp-admin/') )
        ||
-               ( false !== strpos($matches[3], '://') && 0 !== strpos($matches[3], get_option('home')) )
+               ( false !== strpos( $matches[3], '://' ) && 0 !== strpos( $matches[3], home_url() ) )
        ||
                ( false !== strpos($matches[3], '/feed/') )
        ||
@@ -955,13 +1224,13 @@ function switch_theme($template, $stylesheet) {
 /**
  * Checks that current theme files 'index.php' and 'style.css' exists.
  *
- * Does not check the 'default' theme. The 'default' theme should always exist
- * or should have another theme renamed to that template name and directory
- * path. Will switch theme to default if current theme does not validate.
+ * Does not check the default theme, which is the fallback and should always exist.
+ * Will switch theme to the fallback theme if current theme does not validate.
  * You can use the 'validate_current_theme' filter to return FALSE to
  * disable this functionality.
  *
  * @since 1.5.0
+ * @see WP_DEFAULT_THEME
  *
  * @return bool
  */
@@ -970,13 +1239,13 @@ function validate_current_theme() {
        if ( defined('WP_INSTALLING') || !apply_filters( 'validate_current_theme', true ) )
                return true;
 
-       if ( get_template() != 'default' && !file_exists(get_template_directory() . '/index.php') ) {
-               switch_theme('default', 'default');
+       if ( get_template() != WP_DEFAULT_THEME && !file_exists(get_template_directory() . '/index.php') ) {
+               switch_theme( WP_DEFAULT_THEME, WP_DEFAULT_THEME );
                return false;
        }
 
-       if ( get_stylesheet() != 'default' && !file_exists(get_template_directory() . '/style.css') ) {
-               switch_theme('default', 'default');
+       if ( get_stylesheet() != WP_DEFAULT_THEME && !file_exists(get_template_directory() . '/style.css') ) {
+               switch_theme( WP_DEFAULT_THEME, WP_DEFAULT_THEME );
                return false;
        }
 
@@ -1001,7 +1270,7 @@ function validate_current_theme() {
 function get_theme_mod($name, $default = false) {
        $theme = get_current_theme();
 
-       $mods = get_option("mods_$theme");
+       $mods = get_option( "mods_$theme" );
 
        if ( isset($mods[$name]) )
                return apply_filters( "theme_mod_$name", $mods[$name] );
@@ -1076,7 +1345,9 @@ function remove_theme_mods() {
  * @return string
  */
 function get_header_textcolor() {
-       return get_theme_mod('header_textcolor', HEADER_TEXTCOLOR);
+       $default = defined('HEADER_TEXTCOLOR') ? HEADER_TEXTCOLOR : '';
+
+       return get_theme_mod('header_textcolor', $default);
 }
 
 /**
@@ -1097,7 +1368,9 @@ function header_textcolor() {
  * @return string
  */
 function get_header_image() {
-       return get_theme_mod('header_image', HEADER_IMAGE);
+       $default = defined('HEADER_IMAGE') ? HEADER_IMAGE : '';
+
+       return get_theme_mod('header_image', $default);
 }
 
 /**
@@ -1121,17 +1394,324 @@ function header_image() {
  * @uses Custom_Image_Header Sets up for $admin_header_callback for administration panel display.
  *
  * @param callback $header_callback Call on 'wp_head' action.
- * @param callback $admin_header_callback Call on administration panels.
+ * @param callback $admin_header_callback Call on custom header administration screen.
+ * @param callback $admin_image_div_callback Output a custom header image div on the custom header administration screen. Optional.
  */
-function add_custom_image_header($header_callback, $admin_header_callback) {
+function add_custom_image_header($header_callback, $admin_header_callback, $admin_image_div_callback = '') {
        if ( ! empty($header_callback) )
                add_action('wp_head', $header_callback);
 
+       add_theme_support( 'custom-header' );
+
        if ( ! is_admin() )
                return;
        require_once(ABSPATH . 'wp-admin/custom-header.php');
-       $GLOBALS['custom_image_header'] =& new Custom_Image_Header($admin_header_callback);
+       $GLOBALS['custom_image_header'] =& new Custom_Image_Header($admin_header_callback, $admin_image_div_callback);
        add_action('admin_menu', array(&$GLOBALS['custom_image_header'], 'init'));
 }
 
+/**
+ * Register a selection of default headers to be displayed by the custom header admin UI.
+ *
+ * @since 3.0.0
+ *
+ * @param array $headers Array of headers keyed by a string id. The ids point to arrays containing 'url', 'thumbnail_url', and 'description' keys.
+ */
+function register_default_headers( $headers ) {
+       global $_wp_default_headers;
+
+       $_wp_default_headers = array_merge( (array) $_wp_default_headers, (array) $headers );
+}
+
+/**
+ * Unregister default headers.
+ *
+ * This function must be called after register_default_headers() has already added the
+ * header you want to remove.
+ *
+ * @see register_default_headers()
+ * @since 3.0.0
+ *
+ * @param string|array The header string id (key of array) to remove, or an array thereof.
+ * @return True on success, false on failure.
+ */
+function unregister_default_headers( $header ) {
+       global $_wp_default_headers;
+       if ( is_array( $header ) ) {
+               array_map( 'unregister_default_headers', $header );
+       } elseif ( isset( $_wp_default_headers[ $header ] ) ) {
+               unset( $_wp_default_headers[ $header ] );
+               return true;
+       } else {
+               return false;
+       }
+}
+
+/**
+ * Retrieve background image for custom background.
+ *
+ * @since 3.0.0
+ *
+ * @return string
+ */
+function get_background_image() {
+       $default = defined('BACKGROUND_IMAGE') ? BACKGROUND_IMAGE : '';
+
+       return get_theme_mod('background_image', $default);
+}
+
+/**
+ * Display background image path.
+ *
+ * @since 3.0.0
+ */
+function background_image() {
+       echo get_background_image();
+}
+
+/**
+ * Retrieve value for custom background color.
+ *
+ * @since 3.0.0
+ * @uses BACKGROUND_COLOR
+ *
+ * @return string
+ */
+function get_background_color() {
+       $default = defined('BACKGROUND_COLOR') ? BACKGROUND_COLOR : '';
+
+       return get_theme_mod('background_color', $default);
+}
+
+/**
+ * Display background color value.
+ *
+ * @since 3.0.0
+ */
+function background_color() {
+       echo get_background_color();
+}
+
+/**
+ * Add callbacks for background image display.
+ *
+ * The parameter $header_callback callback will be required to display the
+ * content for the 'wp_head' action. The parameter $admin_header_callback
+ * callback will be added to Custom_Background class and that will be added
+ * to the 'admin_menu' action.
+ *
+ * @since 3.0.0
+ * @uses Custom_Background Sets up for $admin_header_callback for administration panel display.
+ *
+ * @param callback $header_callback Call on 'wp_head' action.
+ * @param callback $admin_header_callback Call on custom background administration screen.
+ * @param callback $admin_image_div_callback Output a custom background image div on the custom background administration screen. Optional.
+ */
+function add_custom_background($header_callback = '', $admin_header_callback = '', $admin_image_div_callback = '') {
+       if ( isset($GLOBALS['custom_background']) )
+               return;
+
+       if ( empty($header_callback) )
+               $header_callback = '_custom_background_cb';
+
+       add_action('wp_head', $header_callback);
+
+       add_theme_support( 'custom-background' );
+
+       if ( ! is_admin() )
+               return;
+       require_once(ABSPATH . 'wp-admin/custom-background.php');
+       $GLOBALS['custom_background'] =& new Custom_Background($admin_header_callback, $admin_image_div_callback);
+       add_action('admin_menu', array(&$GLOBALS['custom_background'], 'init'));
+}
+
+/**
+ * Default custom background callback.
+ *
+ * @since 3.0.0
+ * @see add_custom_background()
+ * @access protected
+ */
+function _custom_background_cb() {
+       $background = get_background_image();
+       $color = get_background_color();
+       if ( ! $background && ! $color )
+               return;
+
+       $style = $color ? "background-color: #$color;" : '';
+
+       if ( $background ) {
+               $image = " background-image: url('$background');";
+
+               $repeat = get_theme_mod( 'background_repeat', 'repeat' );
+               if ( ! in_array( $repeat, array( 'no-repeat', 'repeat-x', 'repeat-y', 'repeat' ) ) )
+                       $repeat = 'repeat';
+               $repeat = " background-repeat: $repeat;";
+
+               $position = get_theme_mod( 'background_position_x', 'left' );
+               if ( ! in_array( $position, array( 'center', 'right', 'left' ) ) )
+                       $position = 'left';
+               $position = " background-position: top $position;";
+
+               $attachment = get_theme_mod( 'background_attachment', 'scroll' );
+               if ( ! in_array( $attachment, array( 'fixed', 'scroll' ) ) )
+                       $attachment = 'scroll';
+               $attachment = " background-attachment: $attachment;";
+
+               $style .= $image . $repeat . $position . $attachment;
+       }
+?>
+<style type="text/css">
+body { <?php echo trim( $style ); ?> }
+</style>
+<?php
+}
+
+/**
+ * Add callback for custom TinyMCE editor stylesheets.
+ *
+ * The parameter $stylesheet is the name of the stylesheet, relative to
+ * the theme root. It also accepts an array of stylesheets.
+ * It is optional and defaults to 'editor-style.css'.
+ *
+ * @since 3.0.0
+ *
+ * @param mixed $stylesheet Optional. Stylesheet name or array thereof, relative to theme root.
+ *     Defaults to 'editor-style.css'
+ */
+function add_editor_style( $stylesheet = 'editor-style.css' ) {
+
+       add_theme_support( 'editor-style' );
+
+       if ( ! is_admin() )
+               return;
+
+       global $editor_styles;
+       $editor_styles = (array) $editor_styles;
+       $stylesheet    = (array) $stylesheet;
+       if ( is_rtl() ) {
+               $rtl_stylesheet = str_replace('.css', '-rtl.css', $stylesheet[0]);
+               $stylesheet[] = $rtl_stylesheet;
+       }
+
+       $editor_styles = array_merge( $editor_styles, $stylesheet );
+}
+
+/**
+ * Allows a theme to register its support of a certain feature
+ *
+ * Must be called in the theme's functions.php file to work.
+ * If attached to a hook, it must be after_setup_theme.
+ * The init hook may be too late for some features.
+ *
+ * @since 2.9.0
+ * @param string $feature the feature being added
+ */
+function add_theme_support( $feature ) {
+       global $_wp_theme_features;
+
+       if ( func_num_args() == 1 )
+               $_wp_theme_features[$feature] = true;
+       else
+               $_wp_theme_features[$feature] = array_slice( func_get_args(), 1 );
+}
+
+/**
+ * Allows a theme to de-register its support of a certain feature
+ *
+ * Should be called in the theme's functions.php file. Generally would
+ * be used for child themes to override support from the parent theme.
+ *
+ * @since 3.0.0
+ * @see add_theme_support()
+ * @param string $feature the feature being added
+ * @return bool Whether feature was removed.
+ */
+function remove_theme_support( $feature ) {
+       // Blacklist: for internal registrations not used directly by themes.
+       if ( in_array( $feature, array( 'custom-background', 'custom-header', 'editor-style', 'widgets', 'menus' ) ) )
+               return false;
+
+       global $_wp_theme_features;
+
+       if ( ! isset( $_wp_theme_features[$feature] ) )
+               return false;
+       unset( $_wp_theme_features[$feature] );
+       return true;
+}
+
+/**
+ * Checks a theme's support for a given feature
+ *
+ * @since 2.9.0
+ * @param string $feature the feature being checked
+ * @return boolean
+ */
+function current_theme_supports( $feature ) {
+       global $_wp_theme_features;
+
+       if ( !isset( $_wp_theme_features[$feature] ) )
+               return false;
+
+       // If no args passed then no extra checks need be performed
+       if ( func_num_args() <= 1 )
+               return true;
+
+       $args = array_slice( func_get_args(), 1 );
+
+       // @todo Allow pluggable arg checking
+       switch ( $feature ) {
+               case 'post-thumbnails':
+                       // post-thumbnails can be registered for only certain content/post types by passing
+                       // an array of types to add_theme_support().  If no array was passed, then
+                       // any type is accepted
+                       if ( true === $_wp_theme_features[$feature] )  // Registered for all types
+                               return true;
+                       $content_type = $args[0];
+                       if ( in_array($content_type, $_wp_theme_features[$feature][0]) )
+                               return true;
+                       else
+                               return false;
+                       break;
+       }
+
+       return true;
+}
+
+/**
+ * Checks a theme's support for a given feature before loading the functions which implement it.
+ *
+ * @since 2.9.0
+ * @param string $feature the feature being checked
+ * @param string $include the file containing the functions that implement the feature
+ */
+function require_if_theme_supports( $feature, $include) {
+       if ( current_theme_supports( $feature ) )
+               require ( $include );
+}
+
+/**
+ * Checks an attachment being deleted to see if it's a header or background image.
+ *
+ * If true it removes the theme modification which would be pointing at the deleted
+ * attachment
+ *
+ * @access private
+ * @since 3.0.0
+ * @param int $id the attachment id
+ */
+function _delete_attachment_theme_mod( $id ) {
+       $attachment_image = wp_get_attachment_url( $id );
+       $header_image = get_header_image();
+       $background_image = get_background_image();
+
+       if ( $header_image && $header_image == $attachment_image )
+               remove_theme_mod( 'header_image' );
+
+       if ( $background_image && $background_image == $attachment_image )
+               remove_theme_mod( 'background_image' );
+}
+
+add_action( 'delete_attachment', '_delete_attachment_theme_mod' );
+
 ?>