Code Modernization: Replace dirname( __FILE__ ) calls with __DIR__ magic constant.

This avoids the performance overhead of the function call every time `dirname( __FILE__ )` was used instead of `__DIR__`.

This commit also includes:

* Removing unnecessary parentheses from `include`/`require` statements. These are language constructs, not function calls.
* Replacing `include` statements for several files with `require_once`, for consistency:
 * `wp-admin/admin-header.php`
 * `wp-admin/admin-footer.php`
 * `wp-includes/version.php`

Props ayeshrajans, desrosj, valentinbora, jrf, joostdevalk, netweb.
Fixes #48082.

git-svn-id: https://develop.svn.wordpress.org/trunk@47198 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

src/_index.php

@@ -14,4 +14,4 @@
 define( 'WP_USE_THEMES', true );
 
 /** Loads the WordPress Environment and Template */
-require( dirname( __FILE__ ) . '/wp-blog-header.php' );
+require __DIR__ . '/wp-blog-header.php';

src/index.php

@@ -8,7 +8,7 @@
 
 /** Define ABSPATH as this file's directory */
 if ( ! defined( 'ABSPATH' ) ) {
-	define( 'ABSPATH', dirname( __FILE__ ) . '/' );
+	define( 'ABSPATH', __DIR__ . '/' );
 }
 
 if ( file_exists( ABSPATH . 'wp-includes/js/dist/edit-post.js' ) ) {
@@ -17,14 +17,14 @@
 }
 
 define( 'WPINC', 'wp-includes' );
-require_once( ABSPATH . WPINC . '/load.php' );
+require_once ABSPATH . WPINC . '/load.php';
 
 // Standardize $_SERVER variables across setups.
 wp_fix_server_vars();
 
-require_once( ABSPATH . WPINC . '/functions.php' );
+require_once ABSPATH . WPINC . '/functions.php';
 define( 'WP_CONTENT_DIR', ABSPATH . 'wp-content' );
-require_once( ABSPATH . WPINC . '/version.php' );
+require_once ABSPATH . WPINC . '/version.php';
 
 wp_check_php_mysql_versions();
 wp_load_translations_early();

src/js/_enqueues/vendor/tinymce/wp-tinymce.php

@@ -11,7 +11,7 @@
  */
 error_reporting( 0 );
 
-$basepath = dirname( __FILE__ );
+$basepath = __DIR__;
 
 function get_file( $path ) {
 

src/wp-activate.php

@@ -9,9 +9,9 @@
 define( 'WP_INSTALLING', true );
 
 /** Sets up the WordPress Environment. */
-require( dirname( __FILE__ ) . '/wp-load.php' );
+require __DIR__ . '/wp-load.php';
 
-require( dirname( __FILE__ ) . '/wp-blog-header.php' );
+require __DIR__ . '/wp-blog-header.php';
 
 if ( ! is_multisite() ) {
 	wp_redirect( wp_registration_url() );

src/wp-admin/_index.php

@@ -7,10 +7,10 @@
  */
 
 /** Load WordPress Bootstrap */
-require_once( dirname( __FILE__ ) . '/admin.php' );
+require_once __DIR__ . '/admin.php';
 
 /** Load WordPress dashboard API */
-require_once( ABSPATH . 'wp-admin/includes/dashboard.php' );
+require_once ABSPATH . 'wp-admin/includes/dashboard.php';
 
 wp_dashboard_setup();
 
@@ -108,7 +108,7 @@
 	'<p>' . __( '<a href="https://wordpress.org/support/">Support</a>' ) . '</p>'
 );
 
-include( ABSPATH . 'wp-admin/admin-header.php' );
+require_once ABSPATH . 'wp-admin/admin-header.php';
 ?>
 
 <div class="wrap">
@@ -153,4 +153,4 @@
 <?php
 wp_print_community_events_templates();
 
-require( ABSPATH . 'wp-admin/admin-footer.php' );
+require_once ABSPATH . 'wp-admin/admin-footer.php';

src/wp-admin/about.php

@@ -7,14 +7,14 @@
  */
 
 /** WordPress Administration Bootstrap */
-require_once( dirname( __FILE__ ) . '/admin.php' );
+require_once __DIR__ . '/admin.php';
 
 /* translators: Page title of the About WordPress page in the admin. */
 $title = _x( 'About', 'page title' );
 
 list( $display_version ) = explode( '-', get_bloginfo( 'version' ) );
 
-include( ABSPATH . 'wp-admin/admin-header.php' );
+require_once ABSPATH . 'wp-admin/admin-header.php';
 ?>
 	<div class="wrap about__container">
 
@@ -202,7 +202,7 @@
 	</div>
 <?php
 
-include( ABSPATH . 'wp-admin/admin-footer.php' );
+require_once ABSPATH . 'wp-admin/admin-footer.php';
 
 // These are strings we may use to describe maintenance/security releases, where we aim for no new strings.
 return;

src/wp-admin/admin-ajax.php

@@ -19,7 +19,7 @@
 }
 
 /** Load WordPress Bootstrap */
-require_once( dirname( dirname( __FILE__ ) ) . '/wp-load.php' );
+require_once dirname( __DIR__ ) . '/wp-load.php';
 
 /** Allow for cross-domain requests (from the front end). */
 send_origin_headers();
@@ -33,10 +33,10 @@
 }
 
 /** Load WordPress Administration APIs */
-require_once( ABSPATH . 'wp-admin/includes/admin.php' );
+require_once ABSPATH . 'wp-admin/includes/admin.php';
 
 /** Load Ajax Handlers for WordPress Core */
-require_once( ABSPATH . 'wp-admin/includes/ajax-actions.php' );
+require_once ABSPATH . 'wp-admin/includes/ajax-actions.php';
 
 send_nosniff_header();
 nocache_headers();

src/wp-admin/admin-functions.php

@@ -12,4 +12,4 @@
 _deprecated_file( basename( __FILE__ ), '2.5.0', 'wp-admin/includes/admin.php' );
 
 /** WordPress Administration API: Includes all Administration functions. */
-require_once( ABSPATH . 'wp-admin/includes/admin.php' );
+require_once ABSPATH . 'wp-admin/includes/admin.php';

src/wp-admin/admin-header.php

@@ -8,7 +8,7 @@
 
 header( 'Content-Type: ' . get_option( 'html_type' ) . '; charset=' . get_option( 'blog_charset' ) );
 if ( ! defined( 'WP_ADMIN' ) ) {
-	require_once( dirname( __FILE__ ) . '/admin.php' );
+	require_once __DIR__ . '/admin.php';
 }
 
 /**
@@ -233,7 +233,7 @@
 ?>
 
 <div id="wpwrap">
-<?php require( ABSPATH . 'wp-admin/menu-header.php' ); ?>
+<?php require ABSPATH . 'wp-admin/menu-header.php'; ?>
 <div id="wpcontent">
 
 <?php
@@ -289,5 +289,5 @@
 do_action( 'all_admin_notices' );
 
 if ( $parent_file == 'options-general.php' ) {
-	require( ABSPATH . 'wp-admin/options-head.php' );
+	require ABSPATH . 'wp-admin/options-head.php';
 }

src/wp-admin/admin-post.php

@@ -14,15 +14,15 @@
 }
 
 if ( defined( 'ABSPATH' ) ) {
-	require_once( ABSPATH . 'wp-load.php' );
+	require_once ABSPATH . 'wp-load.php';
 } else {
-	require_once( dirname( dirname( __FILE__ ) ) . '/wp-load.php' );
+	require_once dirname( __DIR__ ) . '/wp-load.php';
 }
 
 /** Allow for cross-domain requests (from the front end). */
 send_origin_headers();
 
-require_once( ABSPATH . 'wp-admin/includes/admin.php' );
+require_once ABSPATH . 'wp-admin/includes/admin.php';
 
 nocache_headers();