map_meta_cap()

map_meta_cap( string $cap, int $user_id, mixed $args ): string[]

function map_meta_cap( $cap, $user_id, ...$args ) {
	$caps = array();

	switch ( $cap ) {
		case 'remove_user':
			// In multisite the user must be a super admin to remove themselves.
			if ( isset( $args[0] ) && $user_id === (int) $args[0] && ! is_super_admin( $user_id ) ) {
				$caps[] = 'do_not_allow';
			} else {
				$caps[] = 'remove_users';
			}
			break;
		case 'promote_user':
		case 'add_users':
			$caps[] = 'promote_users';
			break;
		case 'edit_user':
		case 'edit_users':
			// Non-existent users can't edit users, not even themselves.
			if ( $user_id < 1 ) {
				$caps[] = 'do_not_allow';
				break;
			}

			// Allow user to edit themselves.
			if ( 'edit_user' === $cap && isset( $args[0] ) && $user_id === (int) $args[0] ) {
				break;
			}

			// 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'; // edit_user maps to edit_users.
			}
			break;
		case 'delete_post':
		case 'delete_page':
			if ( ! isset( $args[0] ) ) {
				if ( 'delete_post' === $cap ) {
					/* translators: %s: Capability name. */
					$message = __( 'When checking for the %s capability, you must always check it against a specific post.' );
				} else {
					/* translators: %s: Capability name. */
					$message = __( 'When checking for the %s capability, you must always check it against a specific page.' );
				}

				_doing_it_wrong(
					__FUNCTION__,
					sprintf( $message, '<code>' . $cap . '</code>' ),
					'6.1.0'
				);

				$caps[] = 'do_not_allow';
				break;
			}

			$post = get_post( $args[0] );
			if ( ! $post ) {
				$caps[] = 'do_not_allow';
				break;
			}

			if ( 'revision' === $post->post_type ) {
				$caps[] = 'do_not_allow';
				break;
			}

			if ( (int) get_option( 'page_for_posts' ) === $post->ID
				|| (int) get_option( 'page_on_front' ) === $post->ID
			) {
				$caps[] = 'manage_options';
				break;
			}

			$post_type = get_post_type_object( $post->post_type );
			if ( ! $post_type ) {
				/* translators: 1: Post type, 2: Capability name. */
				$message = __( 'The post type %1$s is not registered, so it may not be reliable to check the capability %2$s against a post of that type.' );

				_doing_it_wrong(
					__FUNCTION__,
					sprintf(
						$message,
						'<code>' . $post->post_type . '</code>',
						'<code>' . $cap . '</code>'
					),
					'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 ( 'delete_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 === (int) $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 ) {
					$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[] = $post_type->cap->delete_posts;
				}
			} else {
				// The user is trying to edit someone else's post.
				$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;
				}
			}

			/*
			 * Setting the privacy policy page requires `manage_privacy_options`,
			 * so deleting it should require that too.
			 */
			if ( (int) get_option( 'wp_page_for_privacy_policy' ) === $post->ID ) {
				$caps = array_merge( $caps, map_meta_cap( 'manage_privacy_options', $user_id ) );
			}

			break;
		/*
		 * edit_post breaks down to edit_posts, edit_published_posts, or
		 * edit_others_posts.
		 */
		case 'edit_post':
		case 'edit_page':
			if ( ! isset( $args[0] ) ) {
				if ( 'edit_post' === $cap ) {
					/* translators: %s: Capability name. */
					$message = __( 'When checking for the %s capability, you must always check it against a specific post.' );
				} else {
					/* translators: %s: Capability name. */
					$message = __( 'When checking for the %s capability, you must always check it against a specific page.' );
				}

				_doing_it_wrong(
					__FUNCTION__,
					sprintf( $message, '<code>' . $cap . '</code>' ),
					'6.1.0'
				);

				$caps[] = 'do_not_allow';
				break;
			}

			$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. */
				$message = __( 'The post type %1$s is not registered, so it may not be reliable to check the capability %2$s against a post of that type.' );

				_doing_it_wrong(
					__FUNCTION__,
					sprintf(
						$message,
						'<code>' . $post->post_type . '</code>',
						'<code>' . $cap . '</code>'
					),
					'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 ( '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 === (int) $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 ) {
					$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[] = $post_type->cap->edit_posts;
				}
			} else {
				// The user is trying to edit someone else's post.
				$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;
				}
			}

			/*
			 * Setting the privacy policy page requires `manage_privacy_options`,
			 * so editing it should require that too.
			 */
			if ( (int) get_option( 'wp_page_for_privacy_policy' ) === $post->ID ) {
				$caps = array_merge( $caps, map_meta_cap( 'manage_privacy_options', $user_id ) );
			}

			break;
		case 'read_post':
		case 'read_page':
			if ( ! isset( $args[0] ) ) {
				if ( 'read_post' === $cap ) {
					/* translators: %s: Capability name. */
					$message = __( 'When checking for the %s capability, you must always check it against a specific post.' );
				} else {
					/* translators: %s: Capability name. */
					$message = __( 'When checking for the %s capability, you must always check it against a specific page.' );
				}

				_doing_it_wrong(
					__FUNCTION__,
					sprintf( $message, '<code>' . $cap . '</code>' ),
					'6.1.0'
				);

				$caps[] = 'do_not_allow';
				break;
			}

			$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. */
				$message = __( 'The post type %1$s is not registered, so it may not be reliable to check the capability %2$s against a post of that type.' );

				_doing_it_wrong(
					__FUNCTION__,
					sprintf(
						$message,
						'<code>' . $post->post_type . '</code>',
						'<code>' . $cap . '</code>'
					),
					'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( get_post_status( $post ) );
			if ( ! $status_obj ) {
				/* translators: 1: Post status, 2: Capability name. */
				$message = __( 'The post status %1$s is not registered, so it may not be reliable to check the capability %2$s against a post with that status.' );

				_doing_it_wrong(
					__FUNCTION__,
					sprintf(
						$message,
						'<code>' . get_post_status( $post ) . '</code>',
						'<code>' . $cap . '</code>'
					),
					'5.4.0'
				);

				$caps[] = 'edit_others_posts';
				break;
			}

			if ( $status_obj->public ) {
				$caps[] = $post_type->cap->read;
				break;
			}

			if ( $post->post_author && $user_id === (int) $post->post_author ) {
				$caps[] = $post_type->cap->read;
			} elseif ( $status_obj->private ) {
				$caps[] = $post_type->cap->read_private_posts;
			} else {
				$caps = map_meta_cap( 'edit_post', $user_id, $post->ID );
			}
			break;
		case 'publish_post':
			if ( ! isset( $args[0] ) ) {
				/* translators: %s: Capability name. */
				$message = __( 'When checking for the %s capability, you must always check it against a specific post.' );

				_doing_it_wrong(
					__FUNCTION__,
					sprintf( $message, '<code>' . $cap . '</code>' ),
					'6.1.0'
				);

				$caps[] = 'do_not_allow';
				break;
			}

			$post = get_post( $args[0] );
			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. */
				$message = __( 'The post type %1$s is not registered, so it may not be reliable to check the capability %2$s against a post of that type.' );

				_doing_it_wrong(
					__FUNCTION__,
					sprintf(
						$message,
						'<code>' . $post->post_type . '</code>',
						'<code>' . $cap . '</code>'
					),
					'4.4.0'
				);

				$caps[] = 'edit_others_posts';
				break;
			}

			$caps[] = $post_type->cap->publish_posts;
			break;
		case 'edit_post_meta':
		case 'delete_post_meta':
		case 'add_post_meta':
		case 'edit_comment_meta':
		case 'delete_comment_meta':
		case 'add_comment_meta':
		case 'edit_term_meta':
		case 'delete_term_meta':
		case 'add_term_meta':
		case 'edit_user_meta':
		case 'delete_user_meta':
		case 'add_user_meta':
			$object_type = explode( '_', $cap )[1];

			if ( ! isset( $args[0] ) ) {
				if ( 'post' === $object_type ) {
					/* translators: %s: Capability name. */
					$message = __( 'When checking for the %s capability, you must always check it against a specific post.' );
				} elseif ( 'comment' === $object_type ) {
					/* translators: %s: Capability name. */
					$message = __( 'When checking for the %s capability, you must always check it against a specific comment.' );
				} elseif ( 'term' === $object_type ) {
					/* translators: %s: Capability name. */
					$message = __( 'When checking for the %s capability, you must always check it against a specific term.' );
				} else {
					/* translators: %s: Capability name. */
					$message = __( 'When checking for the %s capability, you must always check it against a specific user.' );
				}

				_doing_it_wrong(
					__FUNCTION__,
					sprintf( $message, '<code>' . $cap . '</code>' ),
					'6.1.0'
				);

				$caps[] = 'do_not_allow';
				break;
			}

			$object_id = (int) $args[0];

			$object_subtype = get_object_subtype( $object_type, $object_id );

			if ( empty( $object_subtype ) ) {
				$caps[] = 'do_not_allow';
				break;
			}

			$caps = map_meta_cap( "edit_{$object_type}", $user_id, $object_id );

			$meta_key = $args[1] ?? false;

			if ( $meta_key ) {
				$allowed = ! is_protected_meta( $meta_key, $object_type );

				if ( has_filter( "auth_{$object_type}_meta_{$meta_key}_for_{$object_subtype}" ) ) {

					/**
					 * Filters whether the user is allowed to edit a specific meta key of a specific object type and subtype.
					 *
					 * The dynamic portions of the hook name, `$object_type`, `$meta_key`,
					 * and `$object_subtype`, refer to the metadata object type (comment, post, term or user),
					 * the meta key value, and the object subtype respectively.
					 *
					 * @since 4.9.8
					 *
					 * @param bool     $allowed   Whether the user can add the object meta. Default false.
					 * @param string   $meta_key  The meta key.
					 * @param int      $object_id Object ID.
					 * @param int      $user_id   User ID.
					 * @param string   $cap       Capability name.
					 * @param string[] $caps      Array of the user's capabilities.
					 */
					$allowed = apply_filters( "auth_{$object_type}_meta_{$meta_key}_for_{$object_subtype}", $allowed, $meta_key, $object_id, $user_id, $cap, $caps );
				} else {

					/**
					 * Filters whether the user is allowed to edit a specific meta key of a specific object type.
					 *
					 * Return true to have the mapped meta caps from `edit_{$object_type}` apply.
					 *
					 * The dynamic portion of the hook name, `$object_type` refers to the object type being filtered.
					 * The dynamic portion of the hook name, `$meta_key`, refers to the meta key passed to map_meta_cap().
					 *
					 * @since 3.3.0 As `auth_post_meta_{$meta_key}`.
					 * @since 4.6.0
					 *
					 * @param bool     $allowed   Whether the user can add the object meta. Default false.
					 * @param string   $meta_key  The meta key.
					 * @param int      $object_id Object ID.
					 * @param int      $user_id   User ID.
					 * @param string   $cap       Capability name.
					 * @param string[] $caps      Array of the user's capabilities.
					 */
					$allowed = apply_filters( "auth_{$object_type}_meta_{$meta_key}", $allowed, $meta_key, $object_id, $user_id, $cap, $caps );
				}

				/**
				 * Filters whether the user is allowed to edit meta for specific object types/subtypes.
				 *
				 * Return true to have the mapped meta caps from `edit_{$object_type}` apply.
				 *
				 * The dynamic portion of the hook name, `$object_type` refers to the object type being filtered.
				 * The dynamic portion of the hook name, `$object_subtype` refers to the object subtype being filtered.
				 * The dynamic portion of the hook name, `$meta_key`, refers to the meta key passed to map_meta_cap().
				 *
				 * @since 4.6.0 As `auth_post_{$post_type}_meta_{$meta_key}`.
				 * @since 4.7.0 Renamed from `auth_post_{$post_type}_meta_{$meta_key}` to
				 *              `auth_{$object_type}_{$object_subtype}_meta_{$meta_key}`.
				 * @deprecated 4.9.8 Use 'auth_{$object_type_meta_{$meta_key}_for_{$object_subtype}'} instead.
				 *
				 * @param bool     $allowed   Whether the user can add the object meta. Default false.
				 * @param string   $meta_key  The meta key.
				 * @param int      $object_id Object ID.
				 * @param int      $user_id   User ID.
				 * @param string   $cap       Capability name.
				 * @param string[] $caps      Array of the user's capabilities.
				 */
				$allowed = apply_filters_deprecated(
					"auth_{$object_type}_{$object_subtype}_meta_{$meta_key}",
					array( $allowed, $meta_key, $object_id, $user_id, $cap, $caps ),
					'4.9.8',
					"auth_{$object_type}_meta_{$meta_key}_for_{$object_subtype}"
				);

				if ( ! $allowed ) {
					$caps[] = $cap;
				}
			}
			break;
		case 'edit_comment':
			if ( ! isset( $args[0] ) ) {
				/* translators: %s: Capability name. */
				$message = __( 'When checking for the %s capability, you must always check it against a specific comment.' );

				_doing_it_wrong(
					__FUNCTION__,
					sprintf( $message, '<code>' . $cap . '</code>' ),
					'6.1.0'
				);

				$caps[] = 'do_not_allow';
				break;
			}

			$comment = get_comment( $args[0] );
			if ( ! $comment ) {
				$caps[] = 'do_not_allow';
				break;
			}

			$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 ) ) ) {
				$caps[] = $cap;
			} else {
				$caps[] = 'do_not_allow';
			}
			break;
		case 'edit_css':
		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[] = 'unfiltered_html';
			}
			break;
		case 'edit_files':
		case 'edit_plugins':
		case 'edit_themes':
			// Disallow the file editors.
			if ( defined( 'DISALLOW_FILE_EDIT' ) && DISALLOW_FILE_EDIT ) {
				$caps[] = 'do_not_allow';
			} elseif ( ! wp_is_file_mod_allowed( 'capability_edit_themes' ) ) {
				$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 updates core, plugin, or theme files.
			 * Files in uploads are excepted.
			 */
			if ( ! wp_is_file_mod_allowed( 'capability_update_core' ) ) {
				$caps[] = 'do_not_allow';
			} elseif ( is_multisite() && ! is_super_admin( $user_id ) ) {
				$caps[] = 'do_not_allow';
			} elseif ( 'upload_themes' === $cap ) {
				$caps[] = 'install_themes';
			} elseif ( 'upload_plugins' === $cap ) {
				$caps[] = 'install_plugins';
			} else {
				$caps[] = $cap;
			}
			break;
		case 'install_languages':
		case 'update_languages':
			if ( ! wp_is_file_mod_allowed( 'can_install_language_pack' ) ) {
				$caps[] = 'do_not_allow';
			} elseif ( is_multisite() && ! is_super_admin( $user_id ) ) {
				$caps[] = 'do_not_allow';
			} else {
				$caps[] = 'install_languages';
			}
			break;
		case 'activate_plugins':
		case 'deactivate_plugins':
		case 'activate_plugin':
		case 'deactivate_plugin':
			$caps[] = 'activate_plugins';
			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 'resume_plugin':
			$caps[] = 'resume_plugins';
			break;
		case 'resume_theme':
			$caps[] = 'resume_themes';
			break;
		case 'delete_user':
		case 'delete_users':
			// If multisite only super admins can delete users.
			if ( is_multisite() &&