WordPress 4.5
[autoinstalls/wordpress.git] / wp-includes / capabilities.php
index 3773b4a8577a3388970f0ed22cc645b04430e281..9ed3447e6c83a9aaeb4bdea4bddd81bc4911a2aa 100644 (file)
 <?php
 /**
- * WordPress Roles and Capabilities.
+ * Core User Role & Capabilities API
  *
  * @package WordPress
- * @subpackage User
+ * @subpackage Users
  */
 
-/**
- * WordPress User Roles.
- *
- * The role option is simple, the structure is organized by role name that store
- * the name in value of the 'name' key. The capabilities are stored as an array
- * in the value of the 'capability' key.
- *
- * <code>
- * array (
- *             'rolename' => array (
- *                     'name' => 'rolename',
- *                     'capabilities' => array()
- *             )
- * )
- * </code>
- *
- * @since 2.0.0
- * @package WordPress
- * @subpackage User
- */
-class WP_Roles {
-       /**
-        * List of roles and capabilities.
-        *
-        * @since 2.0.0
-        * @access public
-        * @var array
-        */
-       var $roles;
-
-       /**
-        * List of the role objects.
-        *
-        * @since 2.0.0
-        * @access public
-        * @var array
-        */
-       var $role_objects = array();
-
-       /**
-        * List of role names.
-        *
-        * @since 2.0.0
-        * @access public
-        * @var array
-        */
-       var $role_names = array();
-
-       /**
-        * Option name for storing role list.
-        *
-        * @since 2.0.0
-        * @access public
-        * @var string
-        */
-       var $role_key;
-
-       /**
-        * Whether to use the database for retrieval and storage.
-        *
-        * @since 2.1.0
-        * @access public
-        * @var bool
-        */
-       var $use_db = true;
-
-       /**
-        * PHP4 Constructor - Call {@link WP_Roles::_init()} method.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @return WP_Roles
-        */
-       function WP_Roles() {
-               $this->_init();
-       }
-
-       /**
-        * Set up the object properties.
-        *
-        * The role key is set to the current prefix for the $wpdb object with
-        * 'user_roles' appended. If the $wp_user_roles global is set, then it will
-        * be used and the role option will not be updated or used.
-        *
-        * @since 2.1.0
-        * @access protected
-        * @uses $wpdb Used to get the database prefix.
-        * @global array $wp_user_roles Used to set the 'roles' property value.
-        */
-       function _init () {
-               global $wpdb, $wp_user_roles;
-               $this->role_key = $wpdb->prefix . 'user_roles';
-               if ( ! empty( $wp_user_roles ) ) {
-                       $this->roles = $wp_user_roles;
-                       $this->use_db = false;
-               } else {
-                       $this->roles = get_option( $this->role_key );
-               }
-
-               if ( empty( $this->roles ) )
-                       return;
-
-               $this->role_objects = array();
-               $this->role_names =  array();
-               foreach ( (array) $this->roles as $role => $data ) {
-                       $this->role_objects[$role] = new WP_Role( $role, $this->roles[$role]['capabilities'] );
-                       $this->role_names[$role] = $this->roles[$role]['name'];
-               }
-       }
-
-       /**
-        * Add role name with capabilities to list.
-        *
-        * Updates the list of roles, if the role doesn't already exist.
-        *
-        * The capabilities are defined in the following format `array( 'read' => true );`
-        * To explicitly deny a role a capability you set the value for that capability to false.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @param string $role Role name.
-        * @param string $display_name Role display name.
-        * @param array $capabilities List of role capabilities in the above format.
-        * @return null|WP_Role WP_Role object if role is added, null if already exists.
-        */
-       function add_role( $role, $display_name, $capabilities = array() ) {
-               if ( isset( $this->roles[$role] ) )
-                       return;
-
-               $this->roles[$role] = array(
-                       'name' => $display_name,
-                       'capabilities' => $capabilities
-                       );
-               if ( $this->use_db )
-                       update_option( $this->role_key, $this->roles );
-               $this->role_objects[$role] = new WP_Role( $role, $capabilities );
-               $this->role_names[$role] = $display_name;
-               return $this->role_objects[$role];
-       }
-
-       /**
-        * Remove role by name.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @param string $role Role name.
-        */
-       function remove_role( $role ) {
-               if ( ! isset( $this->role_objects[$role] ) )
-                       return;
-
-               unset( $this->role_objects[$role] );
-               unset( $this->role_names[$role] );
-               unset( $this->roles[$role] );
-
-               if ( $this->use_db )
-                       update_option( $this->role_key, $this->roles );
-       }
-
-       /**
-        * Add capability to role.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @param string $role Role name.
-        * @param string $cap Capability name.
-        * @param bool $grant Optional, default is true. Whether role is capable of performing capability.
-        */
-       function add_cap( $role, $cap, $grant = true ) {
-               $this->roles[$role]['capabilities'][$cap] = $grant;
-               if ( $this->use_db )
-                       update_option( $this->role_key, $this->roles );
-       }
-
-       /**
-        * Remove capability from role.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @param string $role Role name.
-        * @param string $cap Capability name.
-        */
-       function remove_cap( $role, $cap ) {
-               unset( $this->roles[$role]['capabilities'][$cap] );
-               if ( $this->use_db )
-                       update_option( $this->role_key, $this->roles );
-       }
-
-       /**
-        * Retrieve role object by name.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @param string $role Role name.
-        * @return object|null Null, if role does not exist. WP_Role object, if found.
-        */
-       function &get_role( $role ) {
-               if ( isset( $this->role_objects[$role] ) )
-                       return $this->role_objects[$role];
-               else
-                       return null;
-       }
-
-       /**
-        * Retrieve list of role names.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @return array List of role names.
-        */
-       function get_names() {
-               return $this->role_names;
-       }
-
-       /**
-        * Whether role name is currently in the list of available roles.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @param string $role Role name to look up.
-        * @return bool
-        */
-       function is_role( $role )
-       {
-               return isset( $this->role_names[$role] );
-       }
-}
-
-/**
- * WordPress Role class.
- *
- * @since 2.0.0
- * @package WordPress
- * @subpackage User
- */
-class WP_Role {
-       /**
-        * Role name.
-        *
-        * @since 2.0.0
-        * @access public
-        * @var string
-        */
-       var $name;
-
-       /**
-        * List of capabilities the role contains.
-        *
-        * @since 2.0.0
-        * @access public
-        * @var array
-        */
-       var $capabilities;
-
-       /**
-        * PHP4 Constructor - Set up object properties.
-        *
-        * The list of capabilities, must have the key as the name of the capability
-        * and the value a boolean of whether it is granted to the role.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @param string $role Role name.
-        * @param array $capabilities List of capabilities.
-        * @return WP_Role
-        */
-       function WP_Role( $role, $capabilities ) {
-               $this->name = $role;
-               $this->capabilities = $capabilities;
-       }
-
-       /**
-        * Assign role a capability.
-        *
-        * @see WP_Roles::add_cap() Method uses implementation for role.
-        * @since 2.0.0
-        * @access public
-        *
-        * @param string $cap Capability name.
-        * @param bool $grant Whether role has capability privilege.
-        */
-       function add_cap( $cap, $grant = true ) {
-               global $wp_roles;
-
-               if ( ! isset( $wp_roles ) )
-                       $wp_roles = new WP_Roles();
-
-               $this->capabilities[$cap] = $grant;
-               $wp_roles->add_cap( $this->name, $cap, $grant );
-       }
-
-       /**
-        * Remove capability from role.
-        *
-        * This is a container for {@link WP_Roles::remove_cap()} to remove the
-        * capability from the role. That is to say, that {@link
-        * WP_Roles::remove_cap()} implements the functionality, but it also makes
-        * sense to use this class, because you don't need to enter the role name.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @param string $cap Capability name.
-        */
-       function remove_cap( $cap ) {
-               global $wp_roles;
-
-               if ( ! isset( $wp_roles ) )
-                       $wp_roles = new WP_Roles();
-
-               unset( $this->capabilities[$cap] );
-               $wp_roles->remove_cap( $this->name, $cap );
-       }
-
-       /**
-        * Whether role has capability.
-        *
-        * The capabilities is passed through the 'role_has_cap' filter. The first
-        * parameter for the hook is the list of capabilities the class has
-        * assigned. The second parameter is the capability name to look for. The
-        * third and final parameter for the hook is the role name.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @param string $cap Capability name.
-        * @return bool True, if user has capability. False, if doesn't have capability.
-        */
-       function has_cap( $cap ) {
-               $capabilities = apply_filters( 'role_has_cap', $this->capabilities, $cap, $this->name );
-               if ( !empty( $capabilities[$cap] ) )
-                       return $capabilities[$cap];
-               else
-                       return false;
-       }
-
-}
-
-/**
- * WordPress User class.
- *
- * @since 2.0.0
- * @package WordPress
- * @subpackage User
- */
-class WP_User {
-       /**
-        * User data container.
-        *
-        * This will be set as properties of the object.
-        *
-        * @since 2.0.0
-        * @access private
-        * @var array
-        */
-       var $data;
-
-       /**
-        * The user's ID.
-        *
-        * @since 2.1.0
-        * @access public
-        * @var int
-        */
-       var $ID = 0;
-
-       /**
-        * The deprecated user's ID.
-        *
-        * @since 2.0.0
-        * @access public
-        * @deprecated Use WP_User::$ID
-        * @see WP_User::$ID
-        * @var int
-        */
-       var $id = 0;
-
-       /**
-        * The individual capabilities the user has been given.
-        *
-        * @since 2.0.0
-        * @access public
-        * @var array
-        */
-       var $caps = array();
-
-       /**
-        * User metadata option name.
-        *
-        * @since 2.0.0
-        * @access public
-        * @var string
-        */
-       var $cap_key;
-
-       /**
-        * The roles the user is part of.
-        *
-        * @since 2.0.0
-        * @access public
-        * @var array
-        */
-       var $roles = array();
-
-       /**
-        * All capabilities the user has, including individual and role based.
-        *
-        * @since 2.0.0
-        * @access public
-        * @var array
-        */
-       var $allcaps = array();
-
-       /**
-        * First name of the user.
-        *
-        * Created to prevent notices.
-        *
-        * @since 2.7.0
-        * @access public
-        * @var string
-        */
-       var $first_name = '';
-
-       /**
-        * Last name of the user.
-        *
-        * Created to prevent notices.
-        *
-        * @since 2.7.0
-        * @access public
-        * @var string
-        */
-       var $last_name = '';
-
-       /**
-        * The filter context applied to user data fields.
-        *
-        * @since 2.9.0
-        * @access private
-        * @var string
-        */
-       var $filter = null;
-
-       /**
-        * PHP4 Constructor - Sets up the object properties.
-        *
-        * Retrieves the userdata and then assigns all of the data keys to direct
-        * properties of the object. Calls {@link WP_User::_init_caps()} after
-        * setting up the object's user data properties.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @param int|string $id User's ID or username
-        * @param int $name Optional. User's username
-        * @return WP_User
-        */
-       function WP_User( $id, $name = '' ) {
-
-               if ( empty( $id ) && empty( $name ) )
-                       return;
-
-               if ( ! is_numeric( $id ) ) {
-                       $name = $id;
-                       $id = 0;
-               }
-
-               if ( ! empty( $id ) )
-                       $this->data = get_userdata( $id );
-               else
-                       $this->data = get_userdatabylogin( $name );
-
-               if ( empty( $this->data->ID ) )
-                       return;
-
-               foreach ( get_object_vars( $this->data ) as $key => $value ) {
-                       $this->{$key} = $value;
-               }
-
-               $this->id = $this->ID;
-               $this->_init_caps();
-       }
-
-       /**
-        * Set up capability object properties.
-        *
-        * Will set the value for the 'cap_key' property to current database table
-        * prefix, followed by 'capabilities'. Will then check to see if the
-        * property matching the 'cap_key' exists and is an array. If so, it will be
-        * used.
-        *
-        * @since 2.1.0
-        *
-        * @param string $cap_key Optional capability key
-        * @access protected
-        */
-       function _init_caps( $cap_key = '' ) {
-               global $wpdb;
-               if ( empty($cap_key) )
-                       $this->cap_key = $wpdb->prefix . 'capabilities';
-               else
-                       $this->cap_key = $cap_key;
-               $this->caps = &$this->{$this->cap_key};
-               if ( ! is_array( $this->caps ) )
-                       $this->caps = array();
-               $this->get_role_caps();
-       }
-
-       /**
-        * Retrieve all of the role capabilities and merge with individual capabilities.
-        *
-        * All of the capabilities of the roles the user belongs to are merged with
-        * the users individual roles. This also means that the user can be denied
-        * specific roles that their role might have, but the specific user isn't
-        * granted permission to.
-        *
-        * @since 2.0.0
-        * @uses $wp_roles
-        * @access public
-        */
-       function get_role_caps() {
-               global $wp_roles;
-
-               if ( ! isset( $wp_roles ) )
-                       $wp_roles = new WP_Roles();
-
-               //Filter out caps that are not role names and assign to $this->roles
-               if ( is_array( $this->caps ) )
-                       $this->roles = array_filter( array_keys( $this->caps ), array( &$wp_roles, 'is_role' ) );
-
-               //Build $allcaps from role caps, overlay user's $caps
-               $this->allcaps = array();
-               foreach ( (array) $this->roles as $role ) {
-                       $the_role =& $wp_roles->get_role( $role );
-                       $this->allcaps = array_merge( (array) $this->allcaps, (array) $the_role->capabilities );
-               }
-               $this->allcaps = array_merge( (array) $this->allcaps, (array) $this->caps );
-       }
-
-       /**
-        * Add role to user.
-        *
-        * Updates the user's meta data option with capabilities and roles.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @param string $role Role name.
-        */
-       function add_role( $role ) {
-               $this->caps[$role] = true;
-               update_user_meta( $this->ID, $this->cap_key, $this->caps );
-               $this->get_role_caps();
-               $this->update_user_level_from_caps();
-       }
-
-       /**
-        * Remove role from user.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @param string $role Role name.
-        */
-       function remove_role( $role ) {
-               if ( !in_array($role, $this->roles) )
-                       return;
-               unset( $this->caps[$role] );
-               update_user_meta( $this->ID, $this->cap_key, $this->caps );
-               $this->get_role_caps();
-               $this->update_user_level_from_caps();
-       }
-
-       /**
-        * Set the role of the user.
-        *
-        * This will remove the previous roles of the user and assign the user the
-        * new one. You can set the role to an empty string and it will remove all
-        * of the roles from the user.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @param string $role Role name.
-        */
-       function set_role( $role ) {
-               foreach ( (array) $this->roles as $oldrole )
-                       unset( $this->caps[$oldrole] );
-               if ( !empty( $role ) ) {
-                       $this->caps[$role] = true;
-                       $this->roles = array( $role => true );
-               } else {
-                       $this->roles = false;
-               }
-               update_user_meta( $this->ID, $this->cap_key, $this->caps );
-               $this->get_role_caps();
-               $this->update_user_level_from_caps();
-               do_action( 'set_user_role', $this->ID, $role );
-       }
-
-       /**
-        * Choose the maximum level the user has.
-        *
-        * Will compare the level from the $item parameter against the $max
-        * parameter. If the item is incorrect, then just the $max parameter value
-        * will be returned.
-        *
-        * Used to get the max level based on the capabilities the user has. This
-        * is also based on roles, so if the user is assigned the Administrator role
-        * then the capability 'level_10' will exist and the user will get that
-        * value.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @param int $max Max level of user.
-        * @param string $item Level capability name.
-        * @return int Max Level.
-        */
-       function level_reduction( $max, $item ) {
-               if ( preg_match( '/^level_(10|[0-9])$/i', $item, $matches ) ) {
-                       $level = intval( $matches[1] );
-                       return max( $max, $level );
-               } else {
-                       return $max;
-               }
-       }
-
-       /**
-        * Update the maximum user level for the user.
-        *
-        * Updates the 'user_level' user metadata (includes prefix that is the
-        * database table prefix) with the maximum user level. Gets the value from
-        * the all of the capabilities that the user has.
-        *
-        * @since 2.0.0
-        * @access public
-        */
-       function update_user_level_from_caps() {
-               global $wpdb;
-               $this->user_level = array_reduce( array_keys( $this->allcaps ), array( &$this, 'level_reduction' ), 0 );
-               update_user_meta( $this->ID, $wpdb->prefix . 'user_level', $this->user_level );
-       }
-
-       /**
-        * Add capability and grant or deny access to capability.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @param string $cap Capability name.
-        * @param bool $grant Whether to grant capability to user.
-        */
-       function add_cap( $cap, $grant = true ) {
-               $this->caps[$cap] = $grant;
-               update_user_meta( $this->ID, $this->cap_key, $this->caps );
-       }
-
-       /**
-        * Remove capability from user.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @param string $cap Capability name.
-        */
-       function remove_cap( $cap ) {
-               if ( empty( $this->caps[$cap] ) )
-                       return;
-               unset( $this->caps[$cap] );
-               update_user_meta( $this->ID, $this->cap_key, $this->caps );
-       }
-
-       /**
-        * Remove all of the capabilities of the user.
-        *
-        * @since 2.1.0
-        * @access public
-        */
-       function remove_all_caps() {
-               global $wpdb;
-               $this->caps = array();
-               delete_user_meta( $this->ID, $this->cap_key );
-               delete_user_meta( $this->ID, $wpdb->prefix . 'user_level' );
-               $this->get_role_caps();
-       }
-
-       /**
-        * Whether user has capability or role name.
-        *
-        * This is useful for looking up whether the user has a specific role
-        * assigned to the user. The second optional parameter can also be used to
-        * check for capabilities against a specfic post.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @param string|int $cap Capability or role name to search.
-        * @param int $post_id Optional. Post ID to check capability against specific post.
-        * @return bool True, if user has capability; false, if user does not have capability.
-        */
-       function has_cap( $cap ) {
-               if ( is_numeric( $cap ) ) {
-                       _deprecated_argument( __FUNCTION__, '2.0', __('Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead.') );
-                       $cap = $this->translate_level_to_cap( $cap );
-               }
-
-               $args = array_slice( func_get_args(), 1 );
-               $args = array_merge( array( $cap, $this->ID ), $args );
-               $caps = call_user_func_array( 'map_meta_cap', $args );
-
-               // Multisite super admin has all caps by definition, Unless specifically denied.
-               if ( is_multisite() && is_super_admin( $this->ID ) ) {
-                       if ( in_array('do_not_allow', $caps) )
-                               return false;
-                       return true;
-               }
-
-               // Must have ALL requested caps
-               $capabilities = apply_filters( 'user_has_cap', $this->allcaps, $caps, $args );
-               foreach ( (array) $caps as $cap ) {
-                       //echo "Checking cap $cap<br />";
-                       if ( empty( $capabilities[$cap] ) || !$capabilities[$cap] )
-                               return false;
-               }
-
-               return true;
-       }
-
-       /**
-        * Convert numeric level to level capability name.
-        *
-        * Prepends 'level_' to level number.
-        *
-        * @since 2.0.0
-        * @access public
-        *
-        * @param int $level Level number, 1 to 10.
-        * @return string
-        */
-       function translate_level_to_cap( $level ) {
-               return 'level_' . $level;
-       }
-
-       /**
-        * Set the blog to operate on. Defaults to the current blog.
-        *
-        * @since 3.0.0
-        *
-        * @param int $blog_id Optional Blog ID, defaults to current blog.
-        */
-       function for_blog( $blog_id = '' ) {
-               global $wpdb;
-               if ( ! empty( $blog_id ) )
-                       $cap_key = $wpdb->get_blog_prefix( $blog_id ) . 'capabilities';
-               else
-                       $cap_key = '';
-               $this->_init_caps( $cap_key );
-       }
-}
-
 /**
  * Map meta capabilities to primitive capabilities.
  *
@@ -787,8 +16,14 @@ class WP_User {
  *
  * @since 2.0.0
  *
- * @param string $cap Capability name.
- * @param int $user_id User ID.
+ * @global array $post_type_meta_caps Used to get post type meta capabilities.
+ *
+ * @param string $cap       Capability name.
+ * @param int    $user_id   User ID.
+ * @param int    $object_id Optional. ID of the specific object to check against if `$cap` is a "meta" cap.
+ *                          "Meta" capabilities, e.g. 'edit_post', 'edit_user', etc., are capabilities used
+ *                          by map_meta_cap() to map to other "primitive" capabilities, e.g. 'edit_posts',
+ *                          'edit_others_posts', etc. The parameter is accessed via func_get_args().
  * @return array Actual capabilities for meta capability.
  */
 function map_meta_cap( $cap, $user_id ) {
@@ -799,196 +34,260 @@ function map_meta_cap( $cap, $user_id ) {
        case 'remove_user':
                $caps[] = 'remove_users';
                break;
-       case 'delete_user':
-               $caps[] = 'delete_users';
-               break;
        case 'promote_user':
+       case 'add_users':
                $caps[] = 'promote_users';
                break;
        case 'edit_user':
+       case 'edit_users':
                // Allow user to edit itself
-               if ( isset( $args[0] ) && $user_id == $args[0] )
+               if ( 'edit_user' == $cap && isset( $args[0] ) && $user_id == $args[0] )
                        break;
-               // Fall through
-       case 'edit_users':
-               // If multisite these caps are allowed only for super admins.
-               if ( is_multisite() && !is_super_admin( $user_id ) )
+
+               // In multisite the user must have manage_network_users caps. If editing a super admin, the user must be a super admin.
+               if ( is_multisite() && ( ( ! is_super_admin( $user_id ) && 'edit_user' === $cap && is_super_admin( $args[0] ) ) || ! user_can( $user_id, 'manage_network_users' ) ) ) {
                        $caps[] = 'do_not_allow';
-               else
-                       $caps[] = 'edit_users'; // Explicit due to primitive fall through
+               } else {
+                       $caps[] = 'edit_users'; // edit_user maps to edit_users.
+               }
                break;
        case 'delete_post':
-               $author_data = get_userdata( $user_id );
-               //echo "post ID: {$args[0]}<br />";
+       case 'delete_page':
                $post = get_post( $args[0] );
+               if ( ! $post ) {
+                       $caps[] = 'do_not_allow';
+                       break;
+               }
+
+               if ( 'revision' == $post->post_type ) {
+                       $post = get_post( $post->post_parent );
+                       if ( ! $post ) {
+                               $caps[] = 'do_not_allow';
+                               break;
+                       }
+               }
+
                $post_type = get_post_type_object( $post->post_type );
-               if ( $post_type && 'post' != $post_type->capability_type ) {
-                       $args = array_merge( array( $post_type->cap->delete_post, $user_id ), $args );
-                       return call_user_func_array( 'map_meta_cap', $args );
+               if ( ! $post_type ) {
+                       /* translators: 1: post type, 2: capability name */
+                       _doing_it_wrong( __FUNCTION__, sprintf( __( 'The post type %1$s is not registered, so it may not be reliable to check the capability "%2$s" against a post of that type.' ), $post->post_type, $cap ), '4.4.0' );
+                       $caps[] = 'edit_others_posts';
+                       break;
                }
 
-               if ( '' != $post->post_author ) {
-                       $post_author_data = get_userdata( $post->post_author );
-               } else {
-                       //No author set yet so default to current user for cap checks
-                       $post_author_data = $author_data;
+               if ( ! $post_type->map_meta_cap ) {
+                       $caps[] = $post_type->cap->$cap;
+                       // Prior to 3.1 we would re-call map_meta_cap here.
+                       if ( 'delete_post' == $cap )
+                               $cap = $post_type->cap->$cap;
+                       break;
                }
 
-               // If the user is the author...
-               if ( is_object( $post_author_data ) && $user_id == $post_author_data->ID ) {
-                       // If the post is published...
-                       if ( 'publish' == $post->post_status ) {
-                               $caps[] = 'delete_published_posts';
+               // If the post author is set and the user is the author...
+               if ( $post->post_author && $user_id == $post->post_author ) {
+                       // If the post is published or scheduled...
+                       if ( in_array( $post->post_status, array( 'publish', 'future' ), true ) ) {
+                               $caps[] = $post_type->cap->delete_published_posts;
                        } elseif ( 'trash' == $post->post_status ) {
-                               if ('publish' == get_post_meta($post->ID, '_wp_trash_meta_status', true) )
-                                       $caps[] = 'delete_published_posts';
+                               $status = get_post_meta( $post->ID, '_wp_trash_meta_status', true );
+                               if ( in_array( $status, array( 'publish', 'future' ), true ) ) {
+                                       $caps[] = $post_type->cap->delete_published_posts;
+                               } else {
+                                       $caps[] = $post_type->cap->delete_posts;
+                               }
                        } else {
                                // If the post is draft...
-                               $caps[] = 'delete_posts';
+                               $caps[] = $post_type->cap->delete_posts;
                        }
                } else {
                        // The user is trying to edit someone else's post.
-                       $caps[] = 'delete_others_posts';
-                       // The post is published, extra cap required.
-                       if ( 'publish' == $post->post_status )
-                               $caps[] = 'delete_published_posts';
-                       elseif ( 'private' == $post->post_status )
-                               $caps[] = 'delete_private_posts';
-               }
-               break;
-       case 'delete_page':
-               $author_data = get_userdata( $user_id );
-               //echo "post ID: {$args[0]}<br />";
-               $page = get_page( $args[0] );
-               $page_author_data = get_userdata( $page->post_author );
-               //echo "current user id : $user_id, page author id: " . $page_author_data->ID . "<br />";
-               // If the user is the author...
-
-               if ('' != $page->post_author) {
-                       $page_author_data = get_userdata( $page->post_author );
-               } else {
-                       //No author set yet so default to current user for cap checks
-                       $page_author_data = $author_data;
-               }
-
-               if ( is_object( $page_author_data ) && $user_id == $page_author_data->ID ) {
-                       // If the page is published...
-                       if ( $page->post_status == 'publish' ) {
-                               $caps[] = 'delete_published_pages';
-                       } elseif ( 'trash' == $page->post_status ) {
-                               if ('publish' == get_post_meta($page->ID, '_wp_trash_meta_status', true) )
-                                       $caps[] = 'delete_published_pages';
-                       } else {
-                               // If the page is draft...
-                               $caps[] = 'delete_pages';
+                       $caps[] = $post_type->cap->delete_others_posts;
+                       // The post is published or scheduled, extra cap required.
+                       if ( in_array( $post->post_status, array( 'publish', 'future' ), true ) ) {
+                               $caps[] = $post_type->cap->delete_published_posts;
+                       } elseif ( 'private' == $post->post_status ) {
+                               $caps[] = $post_type->cap->delete_private_posts;
                        }
-               } else {
-                       // The user is trying to edit someone else's page.
-                       $caps[] = 'delete_others_pages';
-                       // The page is published, extra cap required.
-                       if ( $page->post_status == 'publish' )
-                               $caps[] = 'delete_published_pages';
-                       elseif ( $page->post_status == 'private' )
-                               $caps[] = 'delete_private_pages';
                }
                break;
                // edit_post breaks down to edit_posts, edit_published_posts, or
                // edit_others_posts
        case 'edit_post':
-               $author_data = get_userdata( $user_id );
-               //echo "post ID: {$args[0]}<br />";
+       case 'edit_page':
                $post = get_post( $args[0] );
+               if ( ! $post ) {
+                       $caps[] = 'do_not_allow';
+                       break;
+               }
+
+               if ( 'revision' == $post->post_type ) {
+                       $post = get_post( $post->post_parent );
+                       if ( ! $post ) {
+                               $caps[] = 'do_not_allow';
+                               break;
+                       }
+               }
+
                $post_type = get_post_type_object( $post->post_type );
-               if ( $post_type && 'post' != $post_type->capability_type ) {
-                       $args = array_merge( array( $post_type->cap->edit_post, $user_id ), $args );
-                       return call_user_func_array( 'map_meta_cap', $args );
+               if ( ! $post_type ) {
+                       /* translators: 1: post type, 2: capability name */
+                       _doing_it_wrong( __FUNCTION__, sprintf( __( 'The post type %1$s is not registered, so it may not be reliable to check the capability "%2$s" against a post of that type.' ), $post->post_type, $cap ), '4.4.0' );
+                       $caps[] = 'edit_others_posts';
+                       break;
                }
-               $post_author_data = get_userdata( $post->post_author );
-               //echo "current user id : $user_id, post author id: " . $post_author_data->ID . "<br />";
-               // If the user is the author...
-               if ( is_object( $post_author_data ) && $user_id == $post_author_data->ID ) {
-                       // If the post is published...
-                       if ( 'publish' == $post->post_status ) {
-                               $caps[] = 'edit_published_posts';
+
+               if ( ! $post_type->map_meta_cap ) {
+                       $caps[] = $post_type->cap->$cap;
+                       // Prior to 3.1 we would re-call map_meta_cap here.
+                       if ( 'edit_post' == $cap )
+                               $cap = $post_type->cap->$cap;
+                       break;
+               }
+
+               // If the post author is set and the user is the author...
+               if ( $post->post_author && $user_id == $post->post_author ) {
+                       // If the post is published or scheduled...
+                       if ( in_array( $post->post_status, array( 'publish', 'future' ), true ) ) {
+                               $caps[] = $post_type->cap->edit_published_posts;
                        } elseif ( 'trash' == $post->post_status ) {
-                               if ('publish' == get_post_meta($post->ID, '_wp_trash_meta_status', true) )
-                                       $caps[] = 'edit_published_posts';
+                               $status = get_post_meta( $post->ID, '_wp_trash_meta_status', true );
+                               if ( in_array( $status, array( 'publish', 'future' ), true ) ) {
+                                       $caps[] = $post_type->cap->edit_published_posts;
+                               } else {
+                                       $caps[] = $post_type->cap->edit_posts;
+                               }
                        } else {
                                // If the post is draft...
-                               $caps[] = 'edit_posts';
+                               $caps[] = $post_type->cap->edit_posts;
                        }
                } else {
                        // The user is trying to edit someone else's post.
-                       $caps[] = 'edit_others_posts';
-                       // The post is published, extra cap required.
-                       if ( 'publish' == $post->post_status )
-                               $caps[] = 'edit_published_posts';
-                       elseif ( 'private' == $post->post_status )
-                               $caps[] = 'edit_private_posts';
+                       $caps[] = $post_type->cap->edit_others_posts;
+                       // The post is published or scheduled, extra cap required.
+                       if ( in_array( $post->post_status, array( 'publish', 'future' ), true ) ) {
+                               $caps[] = $post_type->cap->edit_published_posts;
+                       } elseif ( 'private' == $post->post_status ) {
+                               $caps[] = $post_type->cap->edit_private_posts;
+                       }
                }
                break;
-       case 'edit_page':
-               $author_data = get_userdata( $user_id );
-               //echo "post ID: {$args[0]}<br />";
-               $page = get_page( $args[0] );
-               $page_author_data = get_userdata( $page->post_author );
-               //echo "current user id : $user_id, page author id: " . $page_author_data->ID . "<br />";
-               // If the user is the author...
-               if ( is_object( $page_author_data ) && $user_id == $page_author_data->ID ) {
-                       // If the page is published...
-                       if ( 'publish' == $page->post_status ) {
-                               $caps[] = 'edit_published_pages';
-                       } elseif ( 'trash' == $page->post_status ) {
-                               if ('publish' == get_post_meta($page->ID, '_wp_trash_meta_status', true) )
-                                       $caps[] = 'edit_published_pages';
-                       } else {
-                               // If the page is draft...
-                               $caps[] = 'edit_pages';
+       case 'read_post':
+       case 'read_page':
+               $post = get_post( $args[0] );
+               if ( ! $post ) {
+                       $caps[] = 'do_not_allow';
+                       break;
+               }
+
+               if ( 'revision' == $post->post_type ) {
+                       $post = get_post( $post->post_parent );
+                       if ( ! $post ) {
+                               $caps[] = 'do_not_allow';
+                               break;
                        }
+               }
+
+               $post_type = get_post_type_object( $post->post_type );
+               if ( ! $post_type ) {
+                       /* translators: 1: post type, 2: capability name */
+                       _doing_it_wrong( __FUNCTION__, sprintf( __( 'The post type %1$s is not registered, so it may not be reliable to check the capability "%2$s" against a post of that type.' ), $post->post_type, $cap ), '4.4.0' );
+                       $caps[] = 'edit_others_posts';
+                       break;
+               }
+
+               if ( ! $post_type->map_meta_cap ) {
+                       $caps[] = $post_type->cap->$cap;
+                       // Prior to 3.1 we would re-call map_meta_cap here.
+                       if ( 'read_post' == $cap )
+                               $cap = $post_type->cap->$cap;
+                       break;
+               }
+
+               $status_obj = get_post_status_object( $post->post_status );
+               if ( $status_obj->public ) {
+                       $caps[] = $post_type->cap->read;
+                       break;
+               }
+
+               if ( $post->post_author && $user_id == $post->post_author ) {
+                       $caps[] = $post_type->cap->read;
+               } elseif ( $status_obj->private ) {
+                       $caps[] = $post_type->cap->read_private_posts;
                } else {
-                       // The user is trying to edit someone else's page.
-                       $caps[] = 'edit_others_pages';
-                       // The page is published, extra cap required.
-                       if ( 'publish' == $page->post_status )
-                               $caps[] = 'edit_published_pages';
-                       elseif ( 'private' == $page->post_status )
-                               $caps[] = 'edit_private_pages';
+                       $caps = map_meta_cap( 'edit_post', $user_id, $post->ID );
                }
                break;
-       case 'read_post':
+       case 'publish_post':
                $post = get_post( $args[0] );
-               $post_type = get_post_type_object( $post->post_type );
-               if ( $post_type && 'post' != $post_type->capability_type ) {
-                       $args = array_merge( array( $post_type->cap->read_post, $user_id ), $args );
-                       return call_user_func_array( 'map_meta_cap', $args );
+               if ( ! $post ) {
+                       $caps[] = 'do_not_allow';
+                       break;
                }
 
-               if ( 'private' != $post->post_status ) {
-                       $caps[] = 'read';
+               $post_type = get_post_type_object( $post->post_type );
+               if ( ! $post_type ) {
+                       /* translators: 1: post type, 2: capability name */
+                       _doing_it_wrong( __FUNCTION__, sprintf( __( 'The post type %1$s is not registered, so it may not be reliable to check the capability "%2$s" against a post of that type.' ), $post->post_type, $cap ), '4.4.0' );
+                       $caps[] = 'edit_others_posts';
                        break;
                }
 
-               $author_data = get_userdata( $user_id );
-               $post_author_data = get_userdata( $post->post_author );
-               if ( is_object( $post_author_data ) && $user_id == $post_author_data->ID )
-                       $caps[] = 'read';
-               else
-                       $caps[] = 'read_private_posts';
+               $caps[] = $post_type->cap->publish_posts;
                break;
-       case 'read_page':
-               $page = get_page( $args[0] );
+       case 'edit_post_meta':
+       case 'delete_post_meta':
+       case 'add_post_meta':
+               $post = get_post( $args[0] );
+               if ( ! $post ) {
+                       $caps[] = 'do_not_allow';
+                       break;
+               }
 
-               if ( 'private' != $page->post_status ) {
-                       $caps[] = 'read';
+               $caps = map_meta_cap( 'edit_post', $user_id, $post->ID );
+
+               $meta_key = isset( $args[ 1 ] ) ? $args[ 1 ] : false;
+
+               if ( $meta_key && has_filter( "auth_post_meta_{$meta_key}" ) ) {
+                       /**
+                        * Filter whether the user is allowed to add post meta to a post.
+                        *
+                        * The dynamic portion of the hook name, `$meta_key`, refers to the
+                        * meta key passed to {@see map_meta_cap()}.
+                        *
+                        * @since 3.3.0
+                        *
+                        * @param bool   $allowed  Whether the user can add the post meta. Default false.
+                        * @param string $meta_key The meta key.
+                        * @param int    $post_id  Post ID.
+                        * @param int    $user_id  User ID.
+                        * @param string $cap      Capability name.
+                        * @param array  $caps     User capabilities.
+                        */
+                       $allowed = apply_filters( "auth_post_meta_{$meta_key}", false, $meta_key, $post->ID, $user_id, $cap, $caps );
+                       if ( ! $allowed )
+                               $caps[] = $cap;
+               } elseif ( $meta_key && is_protected_meta( $meta_key, 'post' ) ) {
+                       $caps[] = $cap;
+               }
+               break;
+       case 'edit_comment':
+               $comment = get_comment( $args[0] );
+               if ( ! $comment ) {
+                       $caps[] = 'do_not_allow';
                        break;
                }
 
-               $author_data = get_userdata( $user_id );
-               $page_author_data = get_userdata( $page->post_author );
-               if ( is_object( $page_author_data ) && $user_id == $page_author_data->ID )
-                       $caps[] = 'read';
-               else
-                       $caps[] = 'read_private_pages';
+               $post = get_post( $comment->comment_post_ID );
+
+               /*
+                * If the post doesn't exist, we have an orphaned comment.
+                * Fall back to the edit_posts capability, instead.
+                */
+               if ( $post ) {
+                       $caps = map_meta_cap( 'edit_post', $user_id, $post->ID );
+               } else {
+                       $caps = map_meta_cap( 'edit_posts', $user_id );
+               }
                break;
        case 'unfiltered_upload':
                if ( defined('ALLOW_UNFILTERED_UPLOADS') && ALLOW_UNFILTERED_UPLOADS && ( !is_multisite() || is_super_admin( $user_id ) )  )
@@ -996,64 +295,134 @@ function map_meta_cap( $cap, $user_id ) {
                else
                        $caps[] = 'do_not_allow';
                break;
+       case 'unfiltered_html' :
+               // Disallow unfiltered_html for all users, even admins and super admins.
+               if ( defined( 'DISALLOW_UNFILTERED_HTML' ) && DISALLOW_UNFILTERED_HTML )
+                       $caps[] = 'do_not_allow';
+               elseif ( is_multisite() && ! is_super_admin( $user_id ) )
+                       $caps[] = 'do_not_allow';
+               else
+                       $caps[] = $cap;
+               break;
        case 'edit_files':
        case 'edit_plugins':
        case 'edit_themes':
-               if ( defined('DISALLOW_FILE_EDIT') && DISALLOW_FILE_EDIT ) {
+               // Disallow the file editors.
+               if ( defined( 'DISALLOW_FILE_EDIT' ) && DISALLOW_FILE_EDIT )
                        $caps[] = 'do_not_allow';
-                       break;
-               }
-               // Fall through if not DISALLOW_FILE_EDIT.
+               elseif ( defined( 'DISALLOW_FILE_MODS' ) && DISALLOW_FILE_MODS )
+                       $caps[] = 'do_not_allow';
+               elseif ( is_multisite() && ! is_super_admin( $user_id ) )
+                       $caps[] = 'do_not_allow';
+               else
+                       $caps[] = $cap;
+               break;
        case 'update_plugins':
        case 'delete_plugins':
        case 'install_plugins':
+       case 'upload_plugins':
        case 'update_themes':
        case 'delete_themes':
        case 'install_themes':
+       case 'upload_themes':
        case 'update_core':
-               // Disallow anything that creates, deletes, or edits core, plugin, or theme files.
+               // Disallow anything that creates, deletes, or updates core, plugin, or theme files.
                // Files in uploads are excepted.
-               if ( defined('DISALLOW_FILE_MODS') && DISALLOW_FILE_MODS ) {
+               if ( defined( 'DISALLOW_FILE_MODS' ) && DISALLOW_FILE_MODS ) {
                        $caps[] = 'do_not_allow';
-                       break;
-               }
-               // Fall through if not DISALLOW_FILE_MODS.
-       case 'unfiltered_html':
-               // Disallow unfiltered_html for all users, even admins and super admins.
-               if ( defined('DISALLOW_UNFILTERED_HTML') && DISALLOW_UNFILTERED_HTML ) {
+               } elseif ( is_multisite() && ! is_super_admin( $user_id ) ) {
                        $caps[] = 'do_not_allow';
-                       break;
+               } elseif ( 'upload_themes' === $cap ) {
+                       $caps[] = 'install_themes';
+               } elseif ( 'upload_plugins' === $cap ) {
+                       $caps[] = 'install_plugins';
+               } else {
+                       $caps[] = $cap;
                }
-               // Fall through if not DISALLOW_UNFILTERED_HTML
+               break;
+       case 'activate_plugins':
+               $caps[] = $cap;
+               if ( is_multisite() ) {
+                       // update_, install_, and delete_ are handled above with is_super_admin().
+                       $menu_perms = get_site_option( 'menu_items', array() );
+                       if ( empty( $menu_perms['plugins'] ) )
+                               $caps[] = 'manage_network_plugins';
+               }
+               break;
        case 'delete_user':
        case 'delete_users':
-               // If multisite these caps are allowed only for super admins.
-               if ( is_multisite() && !is_super_admin( $user_id ) )
+               // If multisite only super admins can delete users.
+               if ( is_multisite() && ! is_super_admin( $user_id ) )
                        $caps[] = 'do_not_allow';
                else
-                       $caps[] = $cap;
+                       $caps[] = 'delete_users'; // delete_user maps to delete_users.
                break;
        case 'create_users':
-               if ( is_multisite() && !get_site_option( 'add_new_users' ) )
-                       $caps[] = 'do_not_allow';
+               if ( !is_multisite() )
+                       $caps[] = $cap;
+               elseif ( is_super_admin( $user_id ) || get_site_option( 'add_new_users' ) )
+                       $caps[] = $cap;
                else
+                       $caps[] = 'do_not_allow';
+               break;
+       case 'manage_links' :
+               if ( get_option( 'link_manager_enabled' ) )
                        $caps[] = $cap;
+               else
+                       $caps[] = 'do_not_allow';
+               break;
+       case 'customize' :
+               $caps[] = 'edit_theme_options';
+               break;
+       case 'delete_site':
+               $caps[] = 'manage_options';
                break;
        default:
+               // Handle meta capabilities for custom post types.
+               global $post_type_meta_caps;
+               if ( isset( $post_type_meta_caps[ $cap ] ) ) {
+                       $args = array_merge( array( $post_type_meta_caps[ $cap ], $user_id ), $args );
+                       return call_user_func_array( 'map_meta_cap', $args );
+               }
+
                // If no meta caps match, return the original cap.
                $caps[] = $cap;
        }
 
-       return apply_filters('map_meta_cap', $caps, $cap, $user_id, $args);
+       /**
+        * Filter a user's capabilities depending on specific context and/or privilege.
+        *
+        * @since 2.8.0
+        *
+        * @param array  $caps    Returns the user's actual capabilities.
+        * @param string $cap     Capability name.
+        * @param int    $user_id The user ID.
+        * @param array  $args    Adds the context to the cap. Typically the object ID.
+        */
+       return apply_filters( 'map_meta_cap', $caps, $cap, $user_id, $args );
 }
 
 /**
- * Whether current user has capability or role.
+ * Whether the current user has a specific capability.
+ *
+ * While checking against particular roles in place of a capability is supported
+ * in part, this practice is discouraged as it may produce unreliable results.
+ *
+ * Note: Will always return true if the current user is a super admin, unless specifically denied.
  *
  * @since 2.0.0
  *
- * @param string $capability Capability or role name.
- * @return bool
+ * @see WP_User::has_cap()
+ * @see map_meta_cap()
+ *
+ * @param string $capability Capability name.
+ * @param int    $object_id  Optional. ID of the specific object to check against if `$capability` is a "meta" cap.
+ *                           "Meta" capabilities, e.g. 'edit_post', 'edit_user', etc., are capabilities used
+ *                           by map_meta_cap() to map to other "primitive" capabilities, e.g. 'edit_posts',
+ *                           'edit_others_posts', etc. Accessed via func_get_args() and passed to WP_User::has_cap(),
+ *                           then map_meta_cap().
+ * @return bool Whether the current user has the given capability. If `$capability` is a meta cap and `$object_id` is
+ *              passed, whether the current user has the given meta capability for the given object.
  */
 function current_user_can( $capability ) {
        $current_user = wp_get_current_user();
@@ -1064,37 +433,40 @@ function current_user_can( $capability ) {
        $args = array_slice( func_get_args(), 1 );
        $args = array_merge( array( $capability ), $args );
 
-       return call_user_func_array( array( &$current_user, 'has_cap' ), $args );
+       return call_user_func_array( array( $current_user, 'has_cap' ), $args );
 }
 
 /**
- * Whether current user has a capability or role for a given blog.
+ * Whether current user has a capability or role for a given site.
  *
  * @since 3.0.0
  *
- * @param int $blog_id Blog ID
+ * @param int    $blog_id    Site ID.
  * @param string $capability Capability or role name.
  * @return bool
  */
 function current_user_can_for_blog( $blog_id, $capability ) {
-       $current_user = wp_get_current_user();
+       $switched = is_multisite() ? switch_to_blog( $blog_id ) : false;
 
-    if ( is_multisite() && is_super_admin() )
-               return true;
+       $current_user = wp_get_current_user();
 
-       if ( empty( $current_user ) )
+       if ( empty( $current_user ) ) {
+               if ( $switched ) {
+                       restore_current_blog();
+               }
                return false;
-
-       // Create new object to avoid stomping the global current_user.
-       $user = new WP_User( $current_user->id) ;
-
-       // Set the blog id.  @todo add blog id arg to WP_User constructor?
-       $user->for_blog( $blog_id );
+       }
 
        $args = array_slice( func_get_args(), 2 );
        $args = array_merge( array( $capability ), $args );
 
-       return call_user_func_array( array( &$user, 'has_cap' ), $args );
+       $can = call_user_func_array( array( $current_user, 'has_cap' ), $args );
+
+       if ( $switched ) {
+               restore_current_blog();
+       }
+
+       return $can;
 }
 
 /**
@@ -1110,71 +482,95 @@ function author_can( $post, $capability ) {
        if ( !$post = get_post($post) )
                return false;
 
-       $author = new WP_User( $post->post_author );
+       $author = get_userdata( $post->post_author );
 
-       if ( empty( $author->ID ) )
+       if ( ! $author )
                return false;
 
        $args = array_slice( func_get_args(), 2 );
        $args = array_merge( array( $capability ), $args );
 
-       return call_user_func_array( array( &$author, 'has_cap' ), $args );
+       return call_user_func_array( array( $author, 'has_cap' ), $args );
 }
 
 /**
- * Retrieve role object.
+ * Whether a particular user has capability or role.
  *
- * @see WP_Roles::get_role() Uses method to retrieve role object.
- * @since 2.0.0
+ * @since 3.1.0
  *
- * @param string $role Role name.
- * @return object
+ * @param int|object $user User ID or object.
+ * @param string $capability Capability or role name.
+ * @return bool
  */
-function get_role( $role ) {
+function user_can( $user, $capability ) {
+       if ( ! is_object( $user ) )
+               $user = get_userdata( $user );
+
+       if ( ! $user || ! $user->exists() )
+               return false;
+
+       $args = array_slice( func_get_args(), 2 );
+       $args = array_merge( array( $capability ), $args );
+
+       return call_user_func_array( array( $user, 'has_cap' ), $args );
+}
+
+/**
+ * Retrieves the global WP_Roles instance and instantiates it if necessary.
+ *
+ * @since 4.3.0
+ *
+ * @global WP_Roles $wp_roles WP_Roles global instance.
+ *
+ * @return WP_Roles WP_Roles global instance if not already instantiated.
+ */
+function wp_roles() {
        global $wp_roles;
 
-       if ( ! isset( $wp_roles ) )
+       if ( ! isset( $wp_roles ) ) {
                $wp_roles = new WP_Roles();
+       }
+       return $wp_roles;
+}
 
-       return $wp_roles->get_role( $role );
+/**
+ * Retrieve role object.
+ *
+ * @since 2.0.0
+ *
+ * @param string $role Role name.
+ * @return WP_Role|null WP_Role object if found, null if the role does not exist.
+ */
+function get_role( $role ) {
+       return wp_roles()->get_role( $role );
 }
 
 /**
  * Add role, if it does not exist.
  *
- * @see WP_Roles::add_role() Uses method to add role.
  * @since 2.0.0
  *
  * @param string $role Role name.
  * @param string $display_name Display name for role.
- * @param array $capabilities List of capabilities.
- * @return null|WP_Role WP_Role object if role is added, null if already exists.
+ * @param array $capabilities List of capabilities, e.g. array( 'edit_posts' => true, 'delete_posts' => false );
+ * @return WP_Role|null WP_Role object if role is added, null if already exists.
  */
 function add_role( $role, $display_name, $capabilities = array() ) {
-       global $wp_roles;
-
-       if ( ! isset( $wp_roles ) )
-               $wp_roles = new WP_Roles();
-
-       return $wp_roles->add_role( $role, $display_name, $capabilities );
+       if ( empty( $role ) ) {
+               return;
+       }
+       return wp_roles()->add_role( $role, $display_name, $capabilities );
 }
 
 /**
  * Remove role, if it exists.
  *
- * @see WP_Roles::remove_role() Uses method to remove role.
  * @since 2.0.0
  *
  * @param string $role Role name.
- * @return null
  */
 function remove_role( $role ) {
-       global $wp_roles;
-
-       if ( ! isset( $wp_roles ) )
-               $wp_roles = new WP_Roles();
-
-       return $wp_roles->remove_role( $role );
+       wp_roles()->remove_role( $role );
 }
 
 /**
@@ -1182,7 +578,7 @@ function remove_role( $role ) {
  *
  * @since 3.0.0
  *
- * @uses $super_admins Super admins global variable, if set.
+ * @global array $super_admins
  *
  * @return array List of super admin logins
  */
@@ -1204,16 +600,14 @@ function get_super_admins() {
  * @return bool True if the user is a site admin.
  */
 function is_super_admin( $user_id = false ) {
-       if ( ! $user_id ) {
-               $current_user = wp_get_current_user();
-               $user_id = ! empty($current_user) ? $current_user->id : 0;
-       }
+       if ( ! $user_id || $user_id == get_current_user_id() )
+               $user = wp_get_current_user();
+       else
+               $user = get_userdata( $user_id );
 
-       if ( ! $user_id )
+       if ( ! $user || ! $user->exists() )
                return false;
 
-       $user = new WP_User($user_id);
-
        if ( is_multisite() ) {
                $super_admins = get_super_admins();
                if ( is_array( $super_admins ) && in_array( $user->user_login, $super_admins ) )
@@ -1225,5 +619,3 @@ function is_super_admin( $user_id = false ) {
 
        return false;
 }
-
-?>